# US 10,501,000 B2 · Transportation vehicle

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- Number: US 10,501,000 B2
- Document ID: US10501000B2
- Status: Granted
- Kind: B2
- Application number: 16/081,245
- Filed: 2017-06-01
- Published: 2019-01-10
- Granted: 2019-12-10
- Earliest claimed: 2016-09-16
- Assignees: Hitachi Construction Machinery Co., Ltd.
- Applicants: Hitachi Construction Machinery Co., Ltd.
- Inventors: Yudai Itai
- Web page: https://patentgrep.com/patent/US10501000B2

## CPC

- B60P 1/16: actuated by fluid-operated mechanisms
- B60P 1/045: {Levelling or stabilising systems for tippers (suspensions with levelling or stabilising means for vehicles in general B60G17/00, B60G21/00, using ground-engaging vehicle fittings B60S9/00)}
- F15B 11/20: controlling several interacting or sequentially-operating members
- B60P 1/162: {the hydraulic system itself}
- F15B 11/08: with only one servomotor
- F15B 13/04: for use with a single servomotor
- F15B 13/0401: {Valve members; Fluid interconnections therefor}
- F15B 2211/30565: having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
- F15B 2211/3127: Floating position connecting the working ports and the return line
- F15B 2211/413: the positions being continuously variable, e.g. as realised by proportional valves
- F15B 2211/6336: representing a state of the output member, e.g. position, speed or acceleration
- F15B 2211/6654: Flow rate control
- F15B 2211/7053: Double-acting output members
- F15B 2211/7107: the output members being mechanically linked
- F15B 2211/7128: the chambers being connected in parallel
- F15B 2211/761: Control of a negative load, i.e. of a load generating hydraulic energy
- F15B 2211/781: one or more output members having priority
- B60P: VEHICLES ADAPTED FOR LOAD TRANSPORTATION OR TO TRANSPORT, TO CARRY, OR TO COMPRISE SPECIAL LOADS OR OBJECTS (vehicles with special provisions for transporting patients or disabled persons, or their personal conveyances A61G3/00)
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

A haulage vehicle includes a vessel 3, hoist cylinders 10, a control valve device 16 that controls a supply or discharge of pressurized oil to or from the hoist cylinders 10, a controller 35, and a tilt angle detector 31 that detects a tilt angle of the vessel 3. The controller 35 compares a down assist performing angle, which is a tilt angle preset to determine whether negative pressure control processing needs to be performed for offsetting a force applied in a direction that would cause the hoist cylinders 10 to extend, with the detected tilt angle and, if the detected tilt angle is determined to be equal to or greater than the down assist performing angle, outputs a control valve signal to the control valve device 16 so that the valve is opened to forcibly discharge pressurized oil from the hoist cylinders 10.

## Claims

### Claim 1

A haulage vehicle including a vehicle frame that travels by wheels, a vessel that is mounted tiltably on the vehicle frame and is to be loaded with a payload as an object to be hauled, hoist cylinders that are disposed telescopically between the vessel and the vehicle frame and extends to tilt the vessel with respect to the vehicle frame when ejecting the payload from the vessel, a hydraulic power source that produces pressurized oil to be supplied to the hoist cylinders, a control valve device that is arranged between the hydraulic power source and the hoist cylinders and opens or closes a valve for supplying or discharging the pressurized oil to or from the hoist cylinders, a controller that performs open or closure control on the control valve device, and a tilt angle detector that detects a tilt angle of the vessel with respect to the vehicle frame, wherein:
the controller comprises a down assist control section configured to compare a down assist performing angle, which is a tilt angle preset to determine whether negative pressure control processing needs to be performed for offsetting a force applied in a direction that would cause the hoist cylinders to extend, with the detected tilt angle and, if the detected tilt angle is determined to be equal to or greater than the down assist performing angle, to output a control valve signal to the control valve device so that the valve is opened to forcibly discharge pressurized oil from the hoist cylinders.

### Claim 2 (depends on 1)

The haulage vehicle according to claim 1, further comprising:
a weight detector that detects a weight of the payload loaded on the vessel,
wherein the control valve signal that the down assist control section of the controller outputs commands a degree of opening of the valve, which corresponds to a percentage of the weight of the payload as detected by the weight detector to an allowable weight for payloads to be loaded on the vessel.

### Claim 3 (depends on 1)

The haulage vehicle according to claim 1, further comprising:
a speed detector that detects a travel speed of the haulage vehicle,
wherein the controller is configured to output the control valve signal if the travel speed detected by the speed detector is equal to or greater than a speed threshold preset to determine a stationary state of the haulage vehicle and the tilt angle of the vessel is equal to or greater than the down assist performing angle.