Electric Rack and Pinion Tailgate Actuation for Refuse Vehicles
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Solution Overview
Problem
Hydraulic tailgate actuators in refuse vehicles are prone to leakage, expensive, difficult to service, and fail more frequently in cold temperatures, necessitating a more reliable and energy-efficient alternative.
Innovation Solution
An electrically actuated rack and pinion or worm gear tailgate actuation system that rotates the tailgate between closed and open positions, with an integrated locking mechanism using the same electric actuator, eliminating the need for hydraulic systems and reducing energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuators are used to open and close the tailgate, then the tailgate can be actuated with sufficient force, but the system becomes prone to leakage, expensive, difficult to service, and fails more frequently in cold temperatures
Solution Approach 1:
The patent replaces the hydraulic actuation system with an electric motor directly driving a rack and pinion mechanism. This substitution eliminates hydraulic fluid, pumps, and associated components that cause leakage and reliability issues, while maintaining the sufficient force needed to actuate the tailgate through the mechanical advantage of the gear system.
Solution Approach 2:
The invention extracts and removes the hydraulic system components (hydraulic fluid, pumps, reservoirs, filters) from the tailgate actuation mechanism, retaining only the essential mechanical elements (motor, rack, pinion, brake) needed to perform the actuation function. This extraction eliminates the source of leakage and service difficulties.
2Force
If hydraulic actuators are used for tailgate operation, then adequate force can be applied, but the system becomes expensive and difficult to service
Solution Approach 1:
The patent replaces the complex hydraulic system with a simpler electric motor and rack and pinion mechanism. This mechanical substitution maintains adequate actuation force while dramatically improving serviceability, as electric motors and mechanical gears are standard components that are easier to diagnose, access, and replace compared to hydraulic systems with numerous seals, hoses, and fluid components.
3Ease of operation
If hydraulic systems are used for tailgate actuation, then the tailgate can be opened and closed, but the system is more prone to failure in cold temperatures
Solution Approach 1:
The invention replaces the hydraulic system with an electric motor that operates independently of temperature conditions. The rack and pinion mechanism provides direct mechanical transmission that functions reliably in cold temperatures, eliminating the fluid viscosity and component contraction issues that plague hydraulic systems in cold environments.
4Reliability
If separate locking mechanisms are added to secure the tailgate, then the locking function is improved, but the device complexity increases
Solution Approach 1:
The patent merges the locking function into the existing rack and pinion actuation mechanism by using the brake assembly to engage a locking pin with the tailgate. This integration provides reliable locking without adding a completely separate locking system, as the same motor and mechanical components serve both actuation and locking functions through coordinated operation.
Solution Approach 2:
The electric motor and rack and pinion mechanism serve multiple functions: actuating the tailgate open and closed, and through the brake-assisted locking pin, securing the tailgate in the closed position. This multi-functionality reduces overall system complexity by eliminating the need for entirely separate actuation and locking systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The all-electric tailgate actuation system enhances reliability, energy efficiency, and reduces the need for secondary locking mechanisms, addressing the limitations of hydraulic systems while improving performance in cold temperatures.
Implementation Method 1
an electrically actuated, rack and pinion tailgate actuation system... Rotation of the pinion rotates the arcuate rack to open and close the tailgate
Implementation Method 2
the tailgate actuation system includes a worm gear, for example, coaxial with the tailgate hinge and a worm drive engaged with the worm gear. Rotation of the worm drive rotates the worm gear segment to open and close the tailgate
Implementation Method 3
a brake assembly configured to apply a braking force to the output shaft of the electric motor
Data Source
AI summary
A refuse vehicle body includes an electrically actuated, rack and pinion tailgate actuation system. A tailgate is rotationally coupled to the body and configured to rotate between closed and open positions. The tailgate actuation system may be supported by the body and/or tailgate and is configured rotate the tailgate between the closed and open position. The tailgate actuation system may further optionally include a locking mechanism configured to lock and unlock the tailgate in the closed position using the same electrically powered rotary actuator that opens and closes the tailgate.