The Influence And Discussion Of Brake Fluid On Loader Braking Performance (1)

I. Introduction

In recent years, loader brake system failures have become an increasing trend, especially brake failure, brake system temperature rise, oil leakage from the brake pump vent, and a series of other problems. At present, almost all domestic loader service brake systems use pneumatic brake systems. Top oil caliper disc brake, the selection of brake components is generally the same as that of automobiles. There are many factors that cause the failure of the loader’s braking system, such as damage to the braking components leading to braking failure. In recent years, loader braking systems have become the main factor in the upward trend. The author believes that the decline in the quality of brake fluid and brake pads is also an influencing factor. The following is a brief introduction to the effect of brake fluid on the braking performance of wheel loaders.

2. Loader performance requirements for brake fluid

(1) Good viscosity-temperature and low-temperature properties

Loaders often work in harsh working environments such as mountains and mines, so the working mode of the loader requires the loader to frequently move forward and backward in each working cycle, and the brake pads are in the braking state for a long time, so during the braking process, Due to frictional heating, the friction plate temperature can reach as high as 250°C. Part of its heat is transferred to the brake fluid, causing its working temperature to reach 70℃~90℃. When frequent braking is required in mountainous and other environments, its working temperature can reach 110℃, sometimes as high as 150℃, and in the Northeast in winter The brake fluid temperature in areas such as China and northwest China can be as low as -40°C, so the brake fluid is required to have good viscosity-temperature properties and low-temperature flow properties. Suitable high temperature viscosity, low freezing point and low temperature viscosity.

(2) Proper lubricity

In order to keep the brake cylinder and rubber bowl sliding well, the brake fluid is required to have appropriate lubricity.

(3) Ensure safe and reliable braking without air resistance

Frequent braking when the loader is driving generates a large amount of frictional heat, which increases the temperature of the braking system. If brake fluid with a low boiling point and easy evaporation is used, local braking will occur due to the evaporation of the brake fluid at high temperatures. The pipelines of the braking system are filled with steam, causing air resistance and causing brake failure. Therefore, brake fluid is required to have a higher boiling point and lower evaporability to avoid reducing air lock.

(4) Better corrosion resistance

Brake fluid should have good corrosion resistance on various metal parts of the brake.

(5) Good chemical stability

Brake fluid is used under high humidity for a long time, so it is required that the brake fluid does not undergo thermal decomposition and overlap, which will increase the viscosity of the oil, and is not allowed to generate sludge deposits.

(6) Good adaptability to rubber

There are many rubber seals and cups in the brake system to keep the brake system completely sealed. Therefore, the brake fluid should have good adaptability to the rubber seal to prevent the rubber seals and cups from being insulated due to oil insufficiency. Compatibility leads to expansion and reduced mechanical strength.