HydraForce | G3
Ride Control Is No Longer Optional

Compact wheel loaders, skid-steer loaders, and backhoe loaders may not be the biggest machines on the construction site, but they are often do most of the work. Due to their size, these machines can get into places and do things other construction machines cannot. For compact loaders, the lack of wheel suspension presents a challenge. Driving across a jobsite with a large elevated load, it can be difficult to keep from losing the cargo.

For small and mid-size loaders, the rough ride comes with the territory. We rely on the operator to adjust working habits to accommodate machine performance. This means working more slowly and deliberately, limiting tight turns, extending braking distances, and avoiding difficult terrain. This is a drag on productivity.

Cushioning the movement of the boom while traveling over difficult terrain is key to load stability and vehicle safety. An effective boom suspension system can act to prevent loss and shifting of the load, and a vehicle with a controlled load is easier to maneuver and safer to operate.

Keep your load in the bucket with HydraForce Pressure-balanced Boom Suspension

  • Keep the load in the bucket
  • Increase operator comfort
  • Increase working efficiency
  • Reduce wear on vehicle components
  • Increase travel speeds
  • Decrease braking distances
  • Adapt easily to any system
  • Standardized hardware available for proving

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Pressure-balacnced Suspension


Get More Information
Click the links below to explore technical and sales literature on HydraForce Pressure-balanced Boom Suspension:

Download The PbS Bulletin

Download The PbS Brochure

HPB08-E40 Catalog Page

View PbS Proving Manifold Catalog Page
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Balancing The Pressure
Testing Manifold
  • While most loaders do not employ wheel suspension, the larger and more sophisticated machines are often equipped with some form of accumulator-based boom suspension. This system provides damping of the material load through exchange of fluid with a gas-charged accumulator. The compressible gas is able to absorb shock loads and has an overall decoupling effect that allows the vehicle chassis to ride over rough terrain while the boom is able to “float.” Without this cushioning, bumps are transmitted to the load and the jarring motion can not only cause loss of material, but the flexing of boom and chassis components can set off unwanted oscillations.

    For machines that do feature boom suspension, the challenges are many:
    • Cost of additional components
    • Engaging the suspension during travel and disengaging for grading tasks
    • Adapting the suspension to changing loads
    • Load movement as suspension engages
    • Load movement due to accumulator discharge
    Current Suspension Systems
    Many of the systems available today are simply adjunctive, that is to say: they piggy-back onto the existing boom circuit as an afterthought. These suspension systems lack a pump connection and can only charge while the operator is raising the boom. Accumulator charge is critical to suspension performance. The appropriate charge is always equal to the cylinder pressure. Too high or too low a charge can cause a noticeable load movement as the accumulator rebalances when the system is activated, or

    when digging/dragging. Without a pump connection, these systems are unable to match the load in all operating conditions.

    Finally, valves used to set and maintain the accumulator pressure will all suffer from some amount of leakage. Without a source of makeup flow, this ultimately leads to a creeping load, causing the operator to compensate by adjusting boom elevation.
  • The HPB08-E40
    At the heart of the system is the patent-pending HPB08 E40 pressure-balanced accumulator charging valve. This valve is an externally piloted pressure reducing/relieving valve designed to regulate accumulator charge. With connections to pump and tank it is able to match pressure in the regulated port to pressure in the pilot port, even when the boom cylinder is disengaged from the accumulator.

    The primary difference of this system is that, through the use of a pump connection, it is able to maintain the accumulator charge without borrowing oil from the boom cylinder. This means the boom doesn’t drop during travel, or jerk suddenly when the system is activated, and operators won’t experience mushy performance when digging into a pile of material. It simply performs the way the operator expects.
    • Pressure-balanced accumulator charging
    • Load does not move when system is activated
    • Leakdown protection
    • Charges using pump flow / discharges to reservoir
    • Two solenoid enable valves
    • Quick system tuning

  • Operation
    The manifold has connections for pump, tank, accumulator, boom cylinder rod, and boom cylinder base. Solenoid valves enable suspension operation by connecting the cylinder base to the accumulator and the cylinder rod to the tank. The pressure-balanced accumulator charging valve regulates pressure in the accumulator based on a pilot signal from the boom cylinder base. This pilot connection allows accumulator load-balancing even when the suspension is disengaged.
    HydraForce engineers developed this system to fit a broad range of vehicles and boom configurations. Knowing that although the primary suspension issue is the same for all booms, the differences in vehicle dynamics, hydraulics, and boom geometry require a flexible and adaptable solution. During development, the system was tested on a variety of compact loaders. HydraForce was able to see marked performance improvement in load balancing and leakdown during travel. The ability to observe and document actual machine performance in our Innovation and Technology Center gives HydraForce a distinct advantage in developing components and systems that solve real world problems.
    Any of the orifices in the system can be changed to tune performance. The system allows control of the following performance characteristics:
    • Accumulator charge/discharge rate
    • Pilot circuit damping
    • Cylinder rod-end metering

  • Two Wheel Drive
    This pre-designed manifold is available for proving two-wheel drive systems or systems with two series motors. You can easily add to a test vehicle with a few basic plumbing connections. Built for operation with two hydraulic motors in series, one HTD10-40 provides torque control, an adjustable HFR10-32A limits slip in extreme low traction conditions, while four check valves allow bi-directional operation.
    Four Wheel Drive
    This pre-designed manifold is available for proving four-wheel drive systems. You can easily add to a test vehicle with a few basic plumbing connections. Built for operation with four wheel cross-over drive configurations (FR-RL/FL-RR), two HTD10-40s provide torque control, one for each parallel section, two adjustable HFR10-32As limit slip in extreme low traction conditions, while four check valves allow bi-directional operation.