Self-propelled construction machine

Patent metadata

Field	Value
Publication number	US-11519140-B2
Application number	US-202117211117-A
Country	US
Kind code	B2
Filing date	Mar 24, 2021
Priority date	Apr 3, 2020
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A road milling machine includes a machine frame, at least three travelling devices, a milling drum, and at least one hydraulic drive system. The hydraulic drive system includes at least one hydraulic pump, at least one hydraulic fixed displacement motor for driving at least one driven travelling device, and one each hydraulic variable displacement motor for driving the remaining travelling devices. A first gearbox is arranged between the fixed displacement hydraulic motor and its associated travelling device. One each second gearbox is arranged between each of the hydraulic variable displacement motors and their associated travelling devices. The transmission ratio of the first gearbox is lower than the transmission ratios of the second gearboxes and/or the displacement volume of the fixed displacement motor is smaller than the maximum displacement volume of the variable displacement motors.

First claim

The invention claimed is:

1. A self-propelled construction machine, comprising:
a machine frame;
at least first, second and third traveling devices configured to support the machine frame from a ground surface;
at least one working device supported from the machine frame for working the ground surface;
at least one hydraulic drive system configured to drive at least the first and second traveling devices, the hydraulic drive system including:
at least one hydraulic pump;
a hydraulic fixed displacement motor for driving the first traveling device;
a hydraulic variable displacement motor for driving the second traveling device;
a first gearbox arranged between the hydraulic fixed displacement motor and the first traveling device;
a second gearbox arranged between the hydraulic variable displacement motor and the second traveling device;
wherein:
(a) a transmission ratio of the first gearbox is lower than a transmission ratio of the second gearbox; and/or
(b) a displacement volume of the hydraulic fixed displacement motor is smaller than a maximum displacement volume of the hydraulic variable displacement motor.

2. The self-propelled construction machine of claim 1 , wherein:
both elements (a) and (b) are present.

3. The self-propelled construction machine of claim 1 , wherein:
element (a) is present, but element (b) is not present.

4. The self-propelled construction machine of claim 1 , wherein:
element (b) is present, but element (a) is not present.

5. The self-propelled construction machine of claim 1 , wherein:
element (a) is present and the transmission ratio of the first gearbox is at least 15% lower than the transmission ratio of the second gearbox.

6. The self-propelled construction machine of claim 1 , wherein:
element (a) is present and the transmission ratio of the first gearbox is at least 20% lower than the transmission ratio of the second gearbox.

7. The self-propelled construction machine of claim 1 , wherein:
element (a) is present and the transmission ratio of the first gearbox is 15% to 50% lower than the transmission ratio of the second gearbox.

8. The self-propelled construction machine of claim 1 , wherein:
element (a) is present and the transmission ratio of the first gearbox is 20% to 30% lower than the transmission ratio of the second gearbox.

9. The self-propelled construction machine of claim 1 , wherein:
element (b) is present and the displacement volume of the hydraulic fixed displacement motor is at least 15% smaller than the maximum displacement volume of the hydraulic variable displacement motor.

10. The self-propelled construction machine of claim 1 , wherein:
element (b) is present and the displacement volume of the hydraulic fixed displacement motor is at least 20% smaller than the maximum displacement volume of the hydraulic variable displacement motor.

11. The self-propelled construction machine of claim 1 , wherein:
element (b) is present and the displacement volume of the hydraulic fixed displacement motor is 15% to 50% smaller than the maximum displacement volume of the hydraulic variable displacement motor.

12. The self-propelled construction machine of claim 1 , wherein:
element (b) is present and the displacement volume of the hydraulic fixed displacement motor is 20% to 30% smaller than the maximum displacement volume of the hydraulic variable displacement motor.

13. The self-propelled construction machine of claim 1 , wherein:
at least one of the first and second gearboxes is a planetary gearbox.

14. The self-propelled construction machine of claim 1 , wherein:
the hydraulic drive system further includes a hydraulic flow divider configured to divide a hydraulic volumetric flow rate into partial volumetric flow rates, wherein a first partial volumetric flow rate drives the hydraulic fixed displacement motor and a second partial volumetric flow rate drives the hydraulic variable displacement motor.

15. The self-propelled construction machine of claim 1 , wherein:
the hydraulic drive system further includes a controllable valve disposed in a supply line associated with the hydraulic fixed displacement motor.

16. The self-propelled construction machine of claim 15 , wherein:
the controllable valve is a throttle valve or a volumetric flow rate control valve.

17. The self-propelled construction machine of claim 1 , further comprising:
a fourth traveling device; and
wherein each of the first, second, third and fourth traveling devices is driven by the hydraulic drive system.

18. The self-propelled construction machine of claim 1 , wherein:
the first traveling device is a pivotable traveling device configured to be pivotable relative to the machine frame about at least one vertical pivoting axis between a pivoted-in position and at least one pivoted-out position.

19. The self-propelled construction machine of claim 1 , wherein:
the hydraulic variable displacement motor is a hydraulic axial piston motor.

20. The self-propelled construction machine of claim 1 , wherein:
the hydraulic pump is a hydraulic axial piston pump.

21. The self-propelled construction machine of claim 1 , wherein:
the hydraulic fixed displacement motor is a non-adjustable axial piston motor.

22. A method for working a ground surface using a self-propelled construction machine, the construction machine including:
a machine frame;
at least first, second and third traveling devices configured to support the machine frame from the ground surface;
at least one working device supported from the machine frame for working the ground surface;
at least one hydraulic drive system configured to drive at least the first and second traveling devices, the hydraulic drive system including:
at least one hydraulic pump;
a hydraulic fixed displacement motor for driving the first traveling device;
a hydraulic variable displacement motor for driving the second traveling device;
a first gearbox arranged between the hydraulic fixed displacement motor and the first traveling device;
a second gearbox arranged between the hydraulic variable displacement motor and the second traveling device;

wherein the method comprises:
(a) operating the first gearbox at a transmission ratio lower than a transmission ratio of the second gearbox; and/or
(b) operating the hydraulic fixed displacement motor at a displacement volume smaller than a maximum displacement volume of the hydraulic variable displacement motor.

23. The method of claim 22 , wherein:
the method includes step (a) and the transmission ratio of the first gearbox is at least 15% lower that the transmission ratio of the second gearbox.

24. The method of claim 22 , wherein:
the method includes step (a) and the transmission ratio of the first gearbox is at least 20% lower that the transmission ratio of the second gearbox.

25. The method of claim 22 , wherein:
the method includes step (b) and the displacement volume of the hydraulic fixed displacement motor is at least 15% lower than the maximum displacement volume of the hydraulic variable displacement motor.

26. The method of claim 22 , wherein:
the method includes step (b) and the displacement volume of the hydraulic fixed displacement motor is at least 20% lower than the maximum displacement volume of the hydraulic variable displacement motor.

27. The method of claim 22 , further comprising:
pivot

Assignees

• Wirtgen Gmbh

Inventors

• Berning Christian
• Drumm Sebastian

Classifications

• E01C19/004

  Devices for guiding or controlling the machines along a predetermined path (for graders or bulldozers E02F3/841; for other soil-shifting machines E02F9/2045) · CPC title

• E01C23/088 Primary

  Rotary tools, e.g. milling drums {(for forming recesses to receive marking materials E01C23/0946)} · CPC title

• B60Y2200/41

  Construction vehicles, e.g. graders, excavators · CPC title

• B28D1/18

  by milling, e.g. channelling by means of milling tools · CPC title

• F16H2047/025

  the fluid gearing comprising a plurality of pumps or motors · CPC title