SUSPENSION SYSTEM

Abstract

A suspension system includes a hydraulic cylinder having a piston chamber in which a piston moves and a rod chamber in which a rod moves. The hydraulic cylinder operably moves between a retraction and an extension. The system also includes a throttle valve, a branching, and a hydraulic reservoir fluidly coupled to the hydraulic cylinder. A fluid flow from the piston chamber is divided at the branching into a first fluid flow portion and a second fluid flow portion. The first fluid flow portion flows to the rod chamber of the hydraulic cylinder, and the second fluid flow portion flows through the throttle valve to the hydraulic reservoir.

Claims

1. A suspension system, comprising: a hydraulic cylinder including a piston chamber in which a piston moves and a rod chamber in which a rod moves, the hydraulic cylinder operably movable between a retraction and an extension; a throttle valve and a branching; a hydraulic reservoir fluidly coupled to the hydraulic cylinder; wherein, a fluid flow from the piston chamber is divided at the branching into a first fluid flow portion and a second fluid flow portion; wherein, the first fluid flow portion flows to the rod chamber of the hydraulic cylinder, and the second fluid flow portion flows through the throttle valve to the hydraulic reservoir.

2. The suspension system of claim 1, wherein, during extension, the fluid flow flows from the rod chamber through the throttle valve.

3. The suspension system of claim 1, further comprising a backflow preventer configured to open during retraction and close during extension, the backflow preventer being disposed in a fluid path between the piston chamber and the throttle valve.

4. The suspension system of claim 1, further comprising a backflow preventer configured to close during retraction and open during extension, the backflow preventer being disposed in a fluid path between the piston chamber and the hydraulic reservoir.

5. The suspension system of claim 1, wherein the rod disposed in the rod chamber comprises the same cross section as a ring-shaped area formed around the rod of the piston.

6. The suspension system of claim 1, wherein the second fluid flow portion flows through the throttle valve during retraction and extension

7. The suspension system of claim 1 wherein the first fluid flow portion and the second fluid flow portion are equal in size.

8. The suspension system of claim 1, wherein a speed of travel of the piston is the same during retraction and extension.

9. The suspension system of claim 1, wherein the hydraulic cylinder is connected to at least one additional hydraulic cylinder via a cross connection.

10. The suspension system of claim 1, wherein the first and second fluid flow portions are divided into equal amounts during retraction, so that the first fluid flow portion is the same as the second fluid flow portion that flows through the throttle to the hydraulic reservoir.

11. A suspension method for a cab of a machine, comprising: providing a hydraulic cylinder having a piston chamber in which a piston moves and a rod chamber in which a rod moves, a throttle valve, a branching, and a hydraulic reservoir fluidly coupled to the hydraulic cylinder; providing a flow of fluid from the piston chamber; dividing the flow of fluid into a first portion and a second portion; flowing the first portion of fluid directly to the rod chamber; and flowing the second portion of fluid through the throttle valve to the hydraulic reservoir.

12. The suspension method of claim 11, further comprising extending the hydraulic cylinder such that the flow of fluid passes through the throttle valve.

13. The suspension method of claim 11, further comprising: moving the hydraulic cylinder in an extension or retraction movement; directing the flow of fluid through the throttle valve during either the extension or retraction movement.

14. The suspension method of claim 13, further comprising providing a throttle such that the flow of fluid passes through the throttle valve and the throttle.

15. The suspension method of claim 13, wherein the moving step comprises moving the hydraulic cylinder in the retraction and extension movement at the same speed of travel.

16. The suspension method of claim 15, further comprising flowing the first portion and the second portion of fluid in equal amounts through the throttle valve.

16. The suspension method of claim 13, wherein during the retraction movement, the first portion and the second portion of fluid flows through the throttle valve.

17. The suspension method of claim 11, wherein the dividing step comprises dividing the first portion and the second portion of fluid into equal amounts during a retraction of the hydraulic cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above-mentioned aspects of the present disclosure and the manner of obtaining them will become more apparent and the disclosure itself will be better understood by reference to the following description of the embodiments of the disclosure, taken in conjunction with the accompanying drawing, wherein:

[0028] FIG. 1 shows a schematic representation of a cab suspension of a tractor in a side view,

[0029] FIG. 2 shows a schematic representation of a cab suspension of a tractor seen from the rear,

[0030] FIG. 3 shows a perspective view of a cab suspension,

[0031] FIG. 4 shows a suspension system with a hydraulic cylinder during retraction,

[0032] FIG. 5 shows a suspension system with a hydraulic cylinder during extension,

[0033] FIG. 6 shows a ratio of a rod cross section to a ring-shaped area on the piston rod side,

[0034] FIG. 7 shows a suspension system with two hydraulic cylinders in cross connection,

[0035] FIG. 8 shows a simplified representation of the cross connection during retraction, and

[0036] FIG. 9 shows a simplified representation of the cross connection during extension.

DETAILED DESCRIPTION

[0037] FIG. 1 shows a schematic representation of a tractor with a cab suspension. Looking in the direction of travel, the cab 1 is supported at its forward side via a bearing 2 and at its rear side via hydraulic cylinders 3. The hydraulic cylinders 3 are connected to a hydraulic reservoir 4. A throttle 5 is disposed in a fluid path between the hydraulic cylinder 3 and the hydraulic reservoir 4. The hydraulic cylinder 3 ensures a suspension of vertical movements of the cab 1.

[0038] FIG. 2 shows a schematic view of the tractor from the rear. Here, the cab 1 of the tractor is suspended via two hydraulic cylinders 3.

[0039] FIG. 3 shows a perspective view of the cab suspension. The front support 2 includes two elastic elements 6 which are made as rubber pads in this example. The elastic elements 6 connect a frame 7 of the cab to the chassis 8 of the vehicle.

[0040] The elastic elements 6 provide for an uncoupling of the movements of the chassis 8 from the frame 7 of the cab 1. At the rear, the frame 7 of the cab 1 is uncoupled in its movements from chassis 8 via the hydraulic cylinders 3. The cab suspension includes a positioning system 9. The positioning system 9 brings the cab into an initial resting position in each case according to load. The positioning system 9 can bring the cab into an appropriate starting position in each case according to the weight of the driver, so that the same starting position of the suspension system is always produced without regard to the actual weight of the driver. For this, the positioning system 9 has appropriate sensors to appropriately adjust the position of the hydraulic cylinders 3.

[0041] The positioning system 9 is a part of the cab suspension. The positioning system 9 may be any conventional positioning system known in the art.

[0042] FIG. 4 shows a hydraulic cylinder 3 of the suspension system during retraction. During retraction, the piston 10 of the hydraulic cylinder 3 moves downward. The hydraulic cylinder 3 includes a rod chamber 11 and a piston chamber 12.

[0043] During retraction, a fluid flow 13 is generated from the piston chamber 12 of the hydraulic cylinder 3 by the downward movement of the piston 10 by a specific travel. The fluid flow 13 flows through a backflow preventer 14, which opens during retraction. At a branching 15 the fluid flow 13 divides into a partial flow 16, which flows into the rod chamber 11 of the hydraulic cylinder 3, and a partial flow 17, which flows through the throttle 18 of a throttle valve 19 to the hydraulic reservoir 4. The throttle valve 19 includes a drive 20, which is made as an electromagnetic actuator in the illustrated embodiment. The throttle valve 19 includes ports for the corresponding flow paths. The throttle valve 19, which is completely closed in the neutral position (for the most part without flow) or has a pre-settable throttling initial opening cross section, releases an increasingly larger fluid cross section in proportion to the adjustment path. There is also the possibility that the throttle valve 19 is completely open in the neutral position (as a rule, without flow) and then is proportionally closed over the adjustment path. The drive 20 includes a return spring, which is not shown. The throttle valve 19 can be returned to its initial position via the return spring.

[0044] The hydraulic reservoir 4 is formed by a membrane reservoir in the illustrated embodiment. Here, the hydraulic reservoir 4 has a separating membrane 21, which separates a gas side 22 from a fluid side 23. The hydraulic reservoir 4 can be preloaded on the gas side 22 in dependence on the fluid pressure and forms an energy reservoir for the stored hydraulic energy.

[0045] The suspension system includes an additional backflow preventer 24, which is closed during retraction and thus prevents a fluid flow from the piston chamber 12 of the hydraulic cylinder 3 directly to the hydraulic reservoir 4. The backflow preventer 24 thus ensures that no bypass flow takes place, so that the fluid flow from the piston chamber 12 of the hydraulic cylinder 3 is sent to the hydraulic reservoir 4 via the throttle 18 of the throttle valve 19.

[0046] FIG. 5 shows the suspension system during extension. The piston 10 moves upward as shown by the arrow and a fluid volume is forced out of the rod chamber 11 of the hydraulic cylinder 3, the volume corresponding to the travel of the piston times the ring-shaped surface area 25 that is formed around the cross-sectional surface area 26 of the rod. The two surfaces 25 and 26 are shown in FIG. 6.

[0047] During the extension shown in FIG. 5, a fluid flow 27 is generated from the rod chamber 11 of the hydraulic cylinder 3. The backflow preventer 14 is closed during extension and prevents a flow to the piston chamber 12 of the hydraulic cylinder 3. The fluid flow 27 from the rod chamber 11 of the hydraulic cylinder 3 flows entirely through the throttle 18 of the throttle valve 19. At a branching, an additional fluid flow 28 from the hydraulic reservoir 4 is added to the fluid flow 27. A fluid flow 29, which is composed of the fluid flow 27 from the rod chamber and the added fluid flow 28 from the hydraulic reservoir 4, flows through the backflow preventer 24 to the piston chamber 12 of the hydraulic cylinder 3. The backflow preventer 24 is open during extension.

[0048] FIG. 7 shows a suspension system with two hydraulic cylinders 3, which are connected by a cross connection. The mode of operation of the cross connection is shown in FIGS. 8 and 9, which for better understanding are shown in simplified form. In this form they are not complete and not functional. The complete, functional version is shown in FIG. 7.

[0049] FIG. 8 shows a simplified representation of the cross connection during retraction. A fluid flow 13 is generated from the piston chamber 12 of the hydraulic cylinder 3 that is on the right in FIG. 8. At a branching 15, the fluid flow 13 divides into a partial flow 16 to the rod chamber 11 of the left-hand hydraulic cylinder 3 in this figure and into a partial flow 17 through a throttle 18 of the throttle valve 19 to a hydraulic reservoir 4. All of the backflow preventers 14 are open during retraction. All of the backflow preventers 24 are closed during retraction and prevent a bypass flow of the fluid flows 13 directly to a hydraulic reservoir 4, so that the fluid flows 13 are forced to flow initially through a throttle valve 19.

[0050] FIG. 9 shows a simplified representation of the cross connection during extension. Correspondingly, the pistons 10 of both hydraulic cylinders 3 move upward. From the left-hand hydraulic cylinder 3 in FIG. 8, a fluid flow 27 flows from the rod chamber 11 through the throttle 18 of the throttle valve 19. The fluid flow 27 forms, with an additional fluid flow 28 that is added from the hydraulic reservoir 24, a fluid flow 29, which flows through the backflow preventer 24 to the piston chamber 12 of the hydraulic cylinder 3 that is on the right in FIG. 8. All of the backflow preventers 24 are open during extension. All of the backflow preventers 14 are closed during extension and prevent a flow of the fluid flows 27 directly to the piston chamber 12, so that the fluid flow 27 is formed to flow through a throttle 18.

[0051] While embodiments incorporating the principles of the present disclosure have been described hereinabove, the present disclosure is not limited to the described embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.