Hydro-pneumatic driven axle suspension
First Claim
1. A hydro-pneumatic suspension system for a front axle of a vehicle, having a pair of hydraulic cylinders, coupled between a chassis of the vehicle and an axle body, each cylinder having a rod end chamber and a piston end chamber, each rod end chamber being connected to a rod end accumulator and to a valve circuit fed by a hydraulic pump, the valve circuit controlling a position of the chassis relative to the axle body, and controlling fluid pressure in the accumulator as a function of load on the axle body, the improvement wherein:
- the suspension system include components which are designed to resiliently suspend the chassis under all loads expected to be applied to the axle body;
a position sensor senses a position of the chassis relative to the axle and generates a position signal representative thereof;
the valve circuit maintains a pressure in the accumulator sufficient to resiliently suspend the axle body under all load and operating conditions, the valve circuit comprising a pair of electromagnetically controlled level control valves, each level control valve having a first port communicated with the hydraulic pump and a second port communicated with a reservoir, one of the level control valves having a third port communicated with the rod end chamber via a first pilot controlled check valve, the other level control valve having a third port communicated with the piston end chamber via a second pilot controlled check valve, each check valve preventing fluid backflow out of the corresponding rod end chamber and piston end chamber; and
a control unit controls the valve circuit as a function of the position signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A hydro-pneumatic axle spring suspension system for the driven axle of an agricultural utility vehicle, in particular for the front axle of an agricultural tractor, is described, which contains at least one hydraulic cylinder arranged between the vehicle chassis and axle body. The rod end chamber and the piston end chamber of the hydraulic cylinder are each connected with at least one accumulator. Furthermore a valve circuit supplied by a hydraulic pump is provided for the control of the level, which controls the pressure of the accumulators as a function of the load on the axle body.
To improve the operating and spring characteristics of the utility vehicle it is proposed that the mechanical and hydraulic components be designed for a spring suspension under maximum load of the axle body. The valve circuit is configured and controlled in such a way that in the accumulators an adequate pressure is constantly maintained in order to make possible a spring suspension of the axle body under all load and operating conditions of the vehicle.
67 Citations
22 Claims
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1. A hydro-pneumatic suspension system for a front axle of a vehicle, having a pair of hydraulic cylinders, coupled between a chassis of the vehicle and an axle body, each cylinder having a rod end chamber and a piston end chamber, each rod end chamber being connected to a rod end accumulator and to a valve circuit fed by a hydraulic pump, the valve circuit controlling a position of the chassis relative to the axle body, and controlling fluid pressure in the accumulator as a function of load on the axle body, the improvement wherein:
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the suspension system include components which are designed to resiliently suspend the chassis under all loads expected to be applied to the axle body; a position sensor senses a position of the chassis relative to the axle and generates a position signal representative thereof; the valve circuit maintains a pressure in the accumulator sufficient to resiliently suspend the axle body under all load and operating conditions, the valve circuit comprising a pair of electromagnetically controlled level control valves, each level control valve having a first port communicated with the hydraulic pump and a second port communicated with a reservoir, one of the level control valves having a third port communicated with the rod end chamber via a first pilot controlled check valve, the other level control valve having a third port communicated with the piston end chamber via a second pilot controlled check valve, each check valve preventing fluid backflow out of the corresponding rod end chamber and piston end chamber; and a control unit controls the valve circuit as a function of the position signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A hydro-pneumatic suspension system for a front axle of a vehicle, having a pair of hydraulic cylinders, coupled between a chassis of the vehicle and an axle body, each cylinder having a rod end chamber and a piston end chamber, each rod end chamber being connected to a rod end accumulator and to a valve circuit fed by a hydraulic pump, the valve circuit controlling a position of the chassis relative to the axle body, and controlling fluid pressure in the accumulator as a function of load on the axle body, the improvement wherein:
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the suspension system include components which are designed to resiliently suspend the chassis under all loads expected to be applied to the axle body; each piston end chamber is oriented upward and each cylinder having a piston rod which is connected to the axle body, the piston end chambers are directly connected with each other and with a pair of piston end accumulators connected in parallel, and the rod end chambers are directly connected with each other and with the rod end accumulator, the piston end accumulators have a total volume which is at least twice as large as a volume of the rod end accumulator; and the valve circuit maintains a pressure in the accumulators sufficient to resiliently suspend the axle body under all load and operating conditions. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A hydro-pneumatic suspension system for a front axle of a vehicle, having a pair of hydraulic cylinders, coupled between a chassis of the vehicle and an axle body, each cylinder having a rod end chamber and a piston end chamber, each rod end chamber being connected to a rod end accumulator, each piston end chamber being connected to a piston end accumulator, said chambers and accumulators being connected to a valve circuit fed by a hydraulic pump, the valve circuit controlling a position of the chassis relative to the axle body, and controlling fluid pressure in the accumulators as a function of load on the axle body, the improvement wherein:
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the suspension system includes components which are designed to resiliently suspend the chassis under all expected loads on the axle body; and the valve circuit maintains a pressure in the accumulators sufficient to resiliently suspend the axle body under all load and operating conditions, the valve circuit maintaining fluid communication between the rod end chamber and the piston end chamber and the corresponding accumulator under all operation conditions. - View Dependent Claims (22)
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Specification