WO2018054739A1

WO2018054739A1 - Axle system

Info

Publication number: WO2018054739A1
Application number: PCT/EP2017/073014
Authority: WO
Inventors: Rainer Stegmann; Florian Hössle
Original assignee: Saf-Holland Gmbh
Priority date: 2016-09-21
Filing date: 2017-09-13
Publication date: 2018-03-29
Also published as: DE102016117818A1; DE102016117818B4

Abstract

The invention relates to an axle system, in particular for use in utility vehicles, comprising an axle tube (2), which is designed in the form of a hollow body, wherein a closure element (3) is provided, which closes the axle tube (2) at one of the distal ends of the axle tube, wherein the axle tube (2) and the closure element (3) enclose a fluid chamber (4), wherein at least one outlet (5) and one inlet (6) are provided on the axle tube (2) and/or on the closure element (3).

Description

axle system

The present invention relates to an axle system, in particular for use in commercial vehicles. In this case, the invention particularly relates to an axle system for a commercial vehicle, on which a hydraulic system is operated.

Commercial vehicles with hydraulically operated systems are already known from the prior art. However, it has been shown that hydraulic systems, in particular due to the high weight and the high space requirement of the components have adverse effects on the productivity and the total load capacity of a commercial vehicle. Thus, for the operation of hydraulic systems, especially in open hydraulic circuits, a large amount of hydraulic fluid is required, which must be carried in storage tanks on the commercial vehicle. In particular, if a plurality of hydraulically operated systems are provided on the commercial vehicle, the required requirement for additional hydraulic fluid, which must be provided in storage containers on the commercial vehicle, is considerable. In addition to the high weight of the containers required for the storage of hydraulic fluid and their high space requirement is disadvantageous for the commercial vehicle.

Object of the present invention is to provide an axle system, which is lighter and reduces the space requirement in the storage of hydraulic fluid for hydraulic circuits. This object is achieved with an axle system according to claim 1. Further advantages and features of the present invention will become apparent from the dependent claims. According to the invention, the axle system comprises an axle tube, which is hollow body-shaped and a closure element which closes the axle tube at one of its distal ends, the axle tube and the closure element enclosing a fluid space, wherein at least one outflow at the axle tube and / or at the closure element - And an inflow is provided. The core of the present invention is the use of an axle tube, which is formed hollow body-shaped and anyway present on a commercial vehicle, for the storage of hydraulic fluid. For this purpose, the axle tube is closed at least at one of its distal ends by a closure element. In a first preferred embodiment, the closure element opposite end of the axle tube is cup-shaped. Axle tube and closure element thereby form a fluid space, which is closed fluid-tight to the environment and is particularly suitable for the storage of hydraulic fluid. The particular suitability for the storage of hydraulic fluid can be achieved in that the inner surface of the axle tube and the closure element is formed metallic or provided with a corresponding coating which is resistant to hydraulic oil. In order to introduce hydraulic fluid into the fluid space and to be able to lead out of this again, an outflow and an inflow are provided on the axle tube and / or on the closure element. In a first preferred embodiment, both the outflow and the inflow are designed as bores in the axle tube, into which corresponding connection elements for connection to fluid lines can be screwed. Alternatively or additionally, the outflow and the inflow can also be provided with a material fit on the axle tube or integrally formed with the axle tube connecting piece, on which in turn corresponding thread geometries for fluid iddicht determination of connecting pieces for hydraulic lines are formed. In a second preferred embodiment, the outflow is arranged on the axle tube and the inflow at the closure element. Particularly preferably, the closure element is designed as a stub axle. Particularly in the case of rigid axles for commercial vehicles, an axle stub is provided on an axle tube, which is hollow-body-shaped, which in the Frame of the present invention is also usable as a closure element. In this case, a fluid-tight, preferably cohesive connection is preferably formed between the closure element and the axle tube. Particularly preferably, the closure element is fixed cohesively directly on the axle tube. For the formation of a cohesive connection in particular the friction welding has proven. Alternatively, however, the closure element can also be welded to the axle tube by means of an inert gas welding process. In addition to the welded connection between the closure element and the axle tube, a sealing compound can be introduced in an overlap region between the closure element and the axle tube for sealing off the fluid space.

Particularly preferably, two closure elements are provided, wherein at each of the two distal ends of the axle tube depending a closure element can be fixed. A particularly favorable production of the axle tube is possible if this is designed as a simple hollow cylindrical tube. According to the invention, at the two distal ends of this open tube a respective closure element is fixed, so that the fluid space is formed between the closure elements and the axis tube. This configuration of the present invention is particularly suitable for use as a rigid axle of a commercial vehicle trailer. In addition, there is the advantage that by using the axle system in the commercial vehicle trailer, the corresponding hydraulic fluid, which is required, for example, by an additional drive system on the trailer, can be arranged or stored in the immediate vicinity of the corresponding hydraulic systems. In particular, the axle system, in which at least one of the closure elements is designed as stub axle and supports a hydrostatic auxiliary drive, the corresponding hydraulic reservoir, which is located in the fluid space within the Achsroh- res, arranged particularly close to the auxiliary drive. As a result, in particular the required length of the hydraulic lines of the hydraulic system can be significantly reduced, in particular in the event that a hydraulic pump, which is provided for the operation of the additional motor, is arranged in close proximity to the axle system.

Further preferably, the closure element has a pressure chamber in which a return means is arranged, wherein the pressure space is separated from the fluid space via a separating element. Particularly preferably, a pressure chamber is formed on the closure element or in the immediate vicinity of or in the vicinity of the closure element, which can be pressurized by the hydraulic fluid in the fluid space and generates a corresponding back pressure in the hydraulic fluid. For this purpose, the pressure chamber on a return means, which exerts a preferably elastic restoring force on a separating element, which in turn separates the pressure chamber from the fluid space. The provision of a pressure chamber within the axle tube offers the advantage that, in particular, excess hydraulic energy, ie hydraulic pressure, can be stored in the axle system and is ready for subsequent applications. As a result, the energy demand of a hydraulic pump, which would otherwise have to apply the full pressure, can be lowered. Such an energy recuperation or energy recovery can be carried out, for example, when a dump truck lowers the tipped loading area, wherein the weight of the loading surface emits a pressure in the hydraulic system, which can be stored by a compression of the pressure chamber in the axle system. This stored pressure both in the pressure chamber and in the fluid space can be reused for the subsequent lifting of the tiltable loading surface, with only the energy losses and the additional weight, which is arranged on the loading surface, must be compensated by the pump.

Particularly preferably, the restoring means exerts a biasing force on the separating element and depresses the fluid space. Advantageously, the restoring means is biased by the pressure in the fluid space such that it exerts the highest possible force on the separating element and depresses the fluid space via this. Particularly preferably, the return means is designed as a spring element, wherein the separating element is a piston which is arranged to be displaceable within the axle tube and guided on the inner wall of the axle tube substantially fluid-tight. This preferred embodiment is characterized by its robustness and longevity. Thus, the connection of a piston and a spring element designed as a particularly preferred spiral spring, an almost unlimited number of load changes, that is depress or expand execute. As a substantially fluid-tight sliding is also considered that on the inner wall of the axle tube, a fluid film adheres, which causes a negligible leakage. Advantageously, by choosing the strength and length of the spring element, a corresponding pressure characteristic when pressing and relieving the fluid space and thus the pressure chamber is possible. The restoring means embodied as a spring element is supported in a particularly preferred manner on a wall of the closure element.

Alternatively, preferably, the separating element is formed as a deformable membrane, wherein the return means is a compressible fluid. This easy to manufacture and particularly light preferred embodiment of the axle system uses as a restoring means a compressible fluid, particularly preferably air. In particular, an elastically deformable, for example rubber-like, material is used as the deformable membrane. The advantage of this embodiment is that, by providing an additional connection to the pressure space, the compressible fluid can be introduced into and removed from the pressure space, so that the pressure characteristic or the pressure profile in the fluid space can be actively changed. In particular, while the pressure chamber could be connected to the pneumatic system of the commercial vehicle, resulting in the possibility to introduce air into the pressure chamber and thus to increase the pressure in the hydraulic system. At the same time, the fluid space can be relieved via outflow of the compressible fluid.

Alternatively preferably spaced from the closure element, a pressure chamber is provided, in which a return means is arranged, wherein a separating element separates the pressure chamber from the fluid space. In addition to the arrangement of the pressure chamber in the immediate vicinity of the closure element, the pressure chamber can also be arranged, for example, centrally in the axle tube. In a further preferred embodiment, the pressure chamber can thereby separate the fluid space into two partial fluid spaces, wherein an inlet or an outlet is provided in each of the fluid spaces. In this way, two separately operated fluid reservoirs, which are acted upon by the pressure chamber but each with the same pressure, are provided. Particularly preferably, this spaced from the closure element pressure chamber is equipped with a separating element which is designed as a membrane, wherein the return means is a gas which can be introduced through an opening in the axle tube in the pressure chamber and discharged therefrom. As already described above, the introduction and removal of gas from and into the pressure chamber is advisable in order to adapt or actively control the corresponding pressure on the hydraulic fluid. Particularly preferably, the separating element is designed as a membrane which is formed substantially sack-shaped or bubble-shaped, wherein an opening of the membrane is provided in the jacket region of the axle tube. Alternatively, the pressure chamber may also be designed to be spherical and without connections for introducing and discharging gas into the pressure chamber, wherein the separating element is preferably a completely closed and particularly preferably spherical membrane.

Furthermore, the fluid space is preferably connected via a line element to a hydraulic pump, wherein the line element is connected to the drain. In particular, for its use as a fluid reservoir in an open hydraulic circuit, the fluid space is preferably fluid-conductively connected to a hydraulic pump via a line element. The corresponding line element is connected to the drain.

Further preferably, a hydrostatic drive can be fixed to the closure element, the closure element having channels for supplying and discharging tion of hydraulic fluid to the hydrostatic drive, wherein a channel opens into the fluid space. In particular, for the preferred case that an additional motor, which is hydraulically operated, on the closure element, which in turn is preferably designed as a stub axle, is set, it can be supplied via channels in the closure element with hydraulic fluid. It is particularly preferred and saves in particular additional external lines when a channel opens directly into the fluid space. As a result, hydraulic fluid "used" by the hydrostatic drive can be conducted back into the fluid reservoir within the axle tube.

Particularly preferably, the outflow is arranged on the axle tube and the inflow is arranged on the closure element.

Further features and advantages of the present invention will become apparent from the following description with reference to the accompanying figures. Individual features, shown only in one of the figures, can also be used in embodiments of other figures, provided that was not explicitly excluded or prohibited by technical features.

Show it:

1 is a partially sectioned view of a preferred embodiment of an axle system according to the invention,

Fig. 2 is a partially sectioned view of another preferred embodiment of an axle system according to the invention, and a partially sectioned view of another preferred embodiment of an axle system according to the invention. The embodiment of an axle system shown in FIG. 1 has an axle tube 2, which is closed at its two distal ends in the longitudinal direction by a respective closure element 3. The axle tube 2 and the closure elements 3 enclose a fluid space 4 for storing hydraulic fluid. Furthermore, the closure elements 3 are preferably welded to the axle tube 2, as indicated by the welds. In the overlap region between the axle tube 2 and the respective closure element 3, at least one fluid seal is preferably provided, which has a sufficient distance to the welded seam formed between the axle tube 2 and the respective closure element 3 so as not to be exposed to the high thermal stress caused by the welding process be. The axle tube 2 also has an outlet 5 and an inlet 6, the outlet 5 being connected via a line element 8 to a hydraulic pump 9, the hydraulic pump 9 sucking hydraulic fluid out of the fluid space 4. The inflow 6, via which the hydraulic fluid is passed back into the fluid space 4, is shown only schematically.

FIG. 2 shows a further preferred embodiment of an axle system according to the present invention, which is based essentially on the embodiment disclosed in FIG. 1. In addition, here is a pressure chamber 7, disposed within the axle tube 2, which reduces the fluid space 4 is reduced and in particular for the pressure of the fluid space 4 is designed. Preferably, the pressure chamber has a separating element 74, which separates the pressure chamber 7 fluid-tight from the fluid chamber 4 and is acted upon by a restoring means 72 with a biasing force. The return means 72 is preferably designed as a spiral spring and acts as a piston formed separating element 74 with a compressive force in the direction of the fluid space 4. The advantage of forming the pressure chamber 7 with piston and coil spring is the particularly robust design and the possibility of high pressure forces on the Transfer fluid space. The fluid film adhering to the inner wall of the axle tube 2 preferably serves to lubricate the sliding surface of the separating element 74. 3 shows a further preferred embodiment of an axle system. In this case, instead of the pressure chamber 7 of Fig. 2, a pressure chamber 7 is shown, which as a separating element 74, a membrane and as a restoring means 72, a compressible medium such as preferably a gas, particularly preferably air used. This pressure chamber 7 could also be arranged at the position of a pressure chamber 7 shown in FIG. FIG. 3 shows a preferred embodiment in which the pressure chamber 7 is bag-shaped and spaced from the distal ends of the axle tube 2. It is possible to change the amount of gas and thus the amount of return means 72 via an inlet on the pressure chamber 7 and in this way to adjust the pressure with which the pressure chamber 7 acts on the fluid space 4. Furthermore, the closure element 3 is preferably designed as a stub axle, on which a hydrostatic drive 10 is fixed. Particularly advantageously, the drive 10 can be supplied with hydraulic fluid via channels 32 running through the closure element 3. One of the channels 32 advantageously runs directly from the drive 10 into the fluid space 4, so that, on the one hand, there is a short line path and, on the other hand, an additional line element can be completely eliminated. As a result, the total amount of hydraulic fluid required can be reduced and the weight of the axle system can be reduced overall. In addition, a particularly compact construction of the axle system according to the invention results.

LIST OF REFERENCE NUMBERS

2 axle tube

3 closure element

4 fluid space

5 outflow

6 inflow

7 pressure chamber

8 line element

9 hydraulic pump Hydrostatic drive channel

Return means

separating element

Claims

claims

1 . Axle system, in particular for use in commercial vehicles,

comprising an axle tube (2), which is formed hollow body-shaped, wherein a closure element (3) is provided, which closes the axle tube (2) at one of its distal ends,

wherein the axle tube (2) and the closure element (3) enclose a fluid space (4),

wherein at least one outflow (5) and an inflow (6) are provided on the axle tube (2) and / or on the closure element (3).

2. An axle system according to claim 1,

wherein the closure element (3) is designed as a stub axle.

3. axle system according to claim 2,

wherein the closure element (3) is fixed cohesively directly on the axle tube (2).

4. Axis system according to one of the preceding claims,

wherein two closure elements (3) are provided,

wherein at each of the two distal ends of the axle tube (2) each a closure element (3) can be fixed.

5. Axis system according to one of the preceding claims,

wherein the closure element (3) has a pressure chamber (7) in which a return means (72) is arranged,

wherein via a separating element (74) of the pressure chamber (7) from the fluid space (4) is separated.

6. Axis system according to claim 5,

wherein the return means (72) transmits a biasing force to the separator (74) and depresses the fluid space (4).

7. An axle system according to one of claims 5 or 6,

wherein the return means (72) is designed as a spring element,

wherein the separating element (74) is a piston which is displaceably arranged within the axle tube (2) and slides on the inner wall of the axle tube (2) in a substantially fluid-tight manner.

8. Axis system according to one of claims 5 or 6,

wherein the separating element (74) is formed as a deformable membrane, wherein the return means (72) is a compressible fluid.

9. axle system according to one of claims 1 - 4,

wherein a pressure chamber (7), in which a return means (72) is arranged, is provided at a distance from the closure element (3),

wherein a separating element (74) separates the pressure space (7) from the fluid space (4).

10. Axis system according to claim 9,

wherein the separating element (74) is designed as a membrane,

wherein the return means (72) is a gas which can be introduced through an opening in the axle tube (2) in the pressure chamber (7) and discharged therefrom.

1 1. Axle system according to one of the preceding claims,

wherein the fluid space (4) is connected via a line element (8) to a hydraulic pump (9),

wherein the conduit member (8) is connected to the drain (5).

12. An axle system according to one of the preceding claims,

wherein on the closure element (3) a hydrostatic drive (10) can be fixed is

wherein the closure member (3) has channels (32) for supplying and discharging hydraulic fluid to the hydrostatic drive (10), and wherein a channel (32) opens into the fluid space (4).

Axle system according to one of the preceding claims,

wherein the drain (5) on the axle tube (2) is arranged, and

wherein the inflow (6) is arranged on the closure element (3).