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Hydraulic Case Studies


Hydraulic brake valve enhances mobile equipment

The Problem:
Because of the size of much of today's mobile equipment, hydraulic service brakes are a necessity.

           

 

Its Solution:
A new brake valve was developed to perform two consecutive functions on mobile equipment driven by hydrostatic transmissions (HST): first to destroke the HST, and then to apply the vehicle service brakes. (Some equipment operators describe this logical combination of functions as inching.) Obviously, less braking effort is needed when the transmission is not driving.

Depending on the equipment design, the brake system may have a dedicated pump or it may be tapped into the main hydraulic system. Typically, an accumulator and charge valve ensure that pressure is available to operate the brakes. Inside the brake housing, two spools are mechanically linked to stroke simultaneously. When the operator depresses the brake pedal, the 2-position proportional spool connected to the HST swashplate control modulates that line to tank, and the pump de-strokes. With the HST in neutral, a pilot system between the spools allows the 3-position proportional spool to move independently, to apply the brakes and slow the vehicle. When the brake pedal lets the valve destroke, the brakes release, and the HST re-engages.

Related Applications:
Any application in which brake components need to interface and interact with other systems on the equipment.

How Hydraulics Improved this Application:

  • Activated by push-rod force
  • Used with mineral-based hydraulic oils
  • Custom sizing
  • Compact

This application was developed by MICO, Incorporated. To visit the MICO web site, click here.