EP1172553A2 - Hydraulic transformer - Google Patents

Abstract

The hydro-transformer has a rotor (2), in the chambers of which impellers (6) are installed, which are supported for the control of the movement of a lift component (12). A control device (16,32) has at least three control windows (18,20), which are connected with a supply connection, a work connection and a tank connection. The pressure ratio is adjustable by altering the effective control lengths (1) of the control windows. The control device has a control body (16) in which at least two radially displaced control windows are formed. The windows are connected with the impeller chambers (8) via connecting channels (30), the geometry of which is so selected that the effective control length (1) of the control windows, on an adjustment of the control body, is counterwise variable.

Description

The invention relates to a hydrotransformer the preamble of claim 1.

A hydrotransformer is a unit in which an energy flow Q ₁ xp _{1 is converted} into an energy flow Q ₂ xp ₂ by hydraulic coupling of a hydraulic motor and a pump. In this case, only as much hydraulic energy is drawn from an existing pressure supply as is required to drive a consumer connected to the pump. Such hydraulic transformers can be designed as radial piston machines or as axial piston machines.

US 3,188,963 shows one as a swash plate machine executed hydrotransformer, in which in a rotatable Cylinder-guided displacers on a fixed swash plate are supported. The angle of attack of the swashplate determines the piston stroke of the displacer. The pressure medium supply and removal takes place via a control disc with four control kidneys, one pair of control kidneys each is assigned to the motor or the pump.

In US 3,079,864 is a hydrotransformer in vane construction disclosed. With this solution there are one Large number of displacers displaceable in the radial direction stored in a rotor and biased against a cam ring. The pressure medium supply and discharge is similar to in the case of the above-described solution via an end face Control disc.

From WO 97/31185 A1 and the publication "A new one old acquaintance - the hydrotransformer ", Siegfried Rotthäuser, Peter eighth; O + P "Oil hydraulics and pneumatics" 42 (1998) No. 6; P. 374 ff. Is the so-called INNAS hydrotransformer known where the gear ratio, i.e. the relationship between the supply pressure and the load pressure of the consumer is changeable. This is the control disc with three control kidneys, their Relative position to the dead center positions of the displacers Turning the control disc in relation to the swash plate Axial piston machine is changeable.

In an embodiment disclosed in WO 97/31185 A1 are two of the three control kidneys by one Control recess formed over a slidable Bridge is divided into the two control kidneys. By The web can move along the control recess the effective control length (effective length) of the control kidneys Gear ratio setting can be changed. The guidance and sealing of the control bridge is however relatively difficult, so this solution is difficult is feasible.

In contrast, the invention is based on the object to create a hydrotransformer where the setting the gear ratio compared to the one described above State of the art is simplified.

This task is accomplished with a hydrotransformer solved the features of claim 1.

The hydrotransformer according to the invention is equipped with a Control body provided in the two radial to the displacement spaces a control window arranged are.

In contrast, in the known solution Control window offset on the front in the axial direction Displacement rooms trained. Due to the radially offset Relative arrangement of the control body can this comparatively simply on the outer circumference or in an axial bore of the Rotors are stored. Because the control window is pocket-shaped are formed, the control body is in the axial direction Pressure equalized so that no reaction forces are transmitted become.

The change in the effective tax length of the two Control window is preferably through one in the axial direction running relative movement between control body and Rotor, preferably the control body with respect to Rotor is moved axially. In principle, however, it is also possible to close the rotor with reference to the fixed control body move.

The design of the two control windows is special simply if this is through an approximately rectangular control recess with an approximately diagonal direction Web are formed. This diagonal web can be straight or curved, for example helical.

To tilt the movable with respect to the rotor Control body can prevent the control windows Pressure compensation pockets in the peripheral wall of the control body be assigned so that the compressive forces in the radial direction be balanced. These pressure equalization pockets are preferably offset in the axial direction to the control windows educated.

In one variant, the two are on a diagonal web separate control window the tank connection and the Supply port assigned while a third, larger Control window assigned to the work or consumer connection is.

In an alternative variant, this can be the work connection assigned control window also - similar to that State of the art described at the beginning - on a control disk be formed. The relative position of this Control window with reference to the dead center positions of the displacers cannot be changed. With this variant, the in the control window trained control window two more Transitional breakthroughs are assigned via the dead center positions the transition between the load pressure at the work connection and the supply pressure or the tank pressure can be produced is. The control of the gear ratio takes place via the control body.

The invention can be used in constructions in axial and radial piston design, in the latter Case vane units can be used particularly advantageously are.

Other advantageous developments of the invention are the subject of further subclaims.

Figuren 1 und 2 Prinzipdarstellungen eines erfindungsgemäßen Hydrotransformators in Axialkolbenbauweise;

Figur 3 eine Abwicklung eines Steuerkörpers des Hydrotransformators aus Figur 1;

Figur 4 ein Schnitt entlang der Linie A-A in Figur 3;

Figur 5 eine Steuerscheibe eines weiteren Ausführungsbeispiels eines erfindungsgemäßen Hydrotransformators und

Figur 6 eine schematisierte Abwicklung eines Hydrotransformators zur Erläuterung des zweiten Ausführungsbeispiels.

Preferred exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings.
Show it:

Figures 1 and 2 schematic diagrams of a hydraulic transformer according to the invention in axial piston design;

FIG. 3 shows a development of a control body of the hydraulic transformer from FIG. 1;

FIG. 4 shows a section along the line AA in FIG. 3;

5 shows a control disk of a further exemplary embodiment of a hydraulic transformer according to the invention and

Figure 6 is a schematic development of a hydraulic transformer to explain the second embodiment.

The following pictures are only Principle sketches, based on which the function of the invention Hydrotransformer 1 with radially arranged control should be explained.

Figure 1 shows a longitudinal section through a hydrotransformer 1, which is designed in axial piston design is. This has one in a housing, not shown guided cylinder drum 2 in the a variety of cylinder bores 4 are formed, in which displacer 6 are axially displaceable. The displacers 6 and the cylinder bores 4 delimit displacement spaces 8 which alternately with a dashed line in FIG Tank connection T, a supply connection P and a Work or consumer connection A can be connected. The Displacers 6 are on the foot side against an inclined surface 10 a swash plate 12 biased so that with a relative rotation between swash plate 12 and drum 2 Displacers 6 can be set in a lifting movement.

The drum 2 is penetrated by an axial bore 14, in which a control body displaceable in the axial direction 16 is sealingly guided. In the illustrated in Figure 1 In the exemplary embodiment, the control body 16 is bolt-shaped trained and has on its outer peripheral surface three control windows 18, 20 (see Figure 1) and 22 (see Figure 2). The two control windows 18, 20 are not over channels shown in the rotor or in the control body 16 with connected to the tank connection T or the supply connection P, while the rear control window 22 in FIG. 1 via a corresponding channel with the work or Consumer connection A is connected.

The control windows 18, 20, 22 are through three webs 24, 26, 28 separated from each other, the web between the two control windows 18, 20 formed as a diagonal web 24 is.

Between each displacement space 8 and the axial bore 14 A radial channel 30 extends so that the displacement spaces 8 alternately with the control windows 18, 20, 22 are connectable.

Details of the control body are shown in FIGS. 3 and 4 16 explained. Figure 3 shows a settlement of Control body 16 with a rectangular control window 22 and the two approximately triangular control windows 18, 20 separated by the diagonal web 24 are. The two webs 24, 26 extending in the axial direction separate the control window 24 from the two triangular ones Control windows 18, 20, the dividing line of the settlement divides the web 24 in the middle.

The section plane AA shown in FIG. 1 is also shown in the development according to FIG. 3. In the relative position shown in FIG. 1 between the control body 16 and the drum 2, the control windows 18, 20, 24 are passed over by the cross sections of the mouth of the radial channels 30 along the section line AA. Each displacement chamber 8 is connected to the control window 20 for the length l ₁ and thus to the supply connection P and to the tank connection T for the length l ₂ . Upon further rotation of the drum 2 with respect to the control body 16, the corresponding radial channel 30 passes over the control window 22, so that a connection to the consumer connection is established.

In the relative position shown, the length l ₁ corresponds to the length l ₂ , so that a corresponding transmission ratio is established. The transmission ratio is changed by axially displacing the control body 24 in the direction of the arrow according to FIG. 1, as a result of which the line AA in FIG. 3 shifts accordingly. In Figure 3, an axial position of the control body 16 is indicated with a double dotted line, in which the length l ₁ 'is substantially greater than the effective control length l ₂ ' during which the displacement space in question is connected to the tank connection T - the transmission ratio becomes approximately proportional changed to the ratio of the new effective control lengths l ₁ 'and l ₂ '. FIG. 4 shows a section along the line AA in FIG. 3, from which the ratios of the effective control lengths l ₁ , l ₂ can be seen. The effective length of the rectangular control window 22 remains unchanged.

Instead of the straight web 24 running in the diagonal direction, an arbitrarily curved, for example helically curved web 24 can alternatively be used, so that a non-linear change in the effective control lengths l ₁ , l _{2 can be} set.

In the above-described embodiment, the three control windows 18, 20, 22 for connecting the displacement rooms 8 with the connections P, T and A in the control body 16 trained.

A variant is indicated by dash-dotted lines in FIG. 1, according to which a control disk 32 is assigned to the drum 2 is via which the pressure medium supply to the work connection A is controlled. The control body 16 is then corresponding only with the two remaining connections, the Tank connection T and the supply connection P assigned Control windows 18, 20 provided. Figure 5 shows a schematic View of the end indicated in Figure 1 Control disc 32. In this, the control window 22 as Control kidney trained, which is roughly between the two Dead center positions OT and UT extends. From the control window 22 seen from the dead center positions OT and UT are two comparatively short transition openings 38, 40 are formed, the transition when the dead center positions are exceeded to the supply connection (transition opening 40) or to the tank connection (transition breakthrough 38). that is, in this variant, the control disk 32 are unchanged permanent tax windows / tax breaks, while in the control body 16 by axial displacement variable control window 18, 20 arranged are.

The pressure medium supply from the displacement spaces 8 to the in the control disc 32 formed control window 22 or the transition openings 38, 40 take place via axial channels 42 (indicated by dashed lines in FIG. 1) the displacement rooms 8 open. That is, with this variant A radial channel 30 and open into each displacement space 8 Axial channel 42 through which in connection to the control windows 18, 20 or 22 can be produced.

With this solution, it is particularly easy to attach diametrically to the control windows 18, 20 arranged peripheral surface sections of the control body 16, not shown Training pressure equalization pockets that ensure that the control body 16 by the pressure at the supply connection P not on one side against the inner circumferential wall of the axial bore 14 is pressed so that a slight shift of the control body 16 is possible.

In the variant described first, these pressure compensation pockets axially offset from the control windows 18, 20, 22 are formed.

The principle of operation of the hydrotransformer according to the invention is finally explained with reference to Figure 6. This shows a development of the drum 2 of the last described Embodiment. In processing forms the inclined surface 10 of the swash plate 12 is approximately sinusoidal Control curve, run over by the displacers 8 becomes. According to FIG. 5, on the swash plate 12 face of the drum 2 facing away from the control disk 32 arranged in which the kidney-shaped control window 22nd is trained. In the highly simplified representation 6 shows the variable control windows 18, 20 likewise in the control disk 32 for the sake of simplicity indicated, the effective control length by axial displacement of the only schematically indicated control body 16 takes place. That by moving the control body 16 to the left in the illustration according to FIG. 6 the effective control length of the control window 20 is reduced, while the effective control length of the control window 18 is increased in opposite directions.

As can be seen from the illustration according to FIG the consumer connection connected to the control window 22 A during the upward movement of the displacer 6 with the displacement rooms 8 connected. When reaching the top Dead center position (TDC) becomes the connection of the respective displacement space 8 controlled with the control window 22 and after driving over the web 36 opened so that the Displacement chambers with that formed in the control body 16 Control window 20 connected to the supply port P. are. Depending on the setting of the control body 16 is then the corresponding one on the way to bottom dead center UT Displacement chamber with the control window 18 and thus with the Tank connection T connected. When bottom dead center is reached and driving over the web 34, the connection takes place the displacement chamber 8 with the working connection - the cycle starts again.

As already mentioned, the principle according to the invention is with a control body arranged radially to the displacement spaces also with other types of hydrotransformer, for example Vane cell units can be used. At a such a variant could be the control body, for example be arranged in an axial bore of the rotor, which Radial holes are connected to the displacement spaces.

Disclosed is a hydrotransformer with a rotor, in which a large number of displacers is guided. The the Displacer-absorbing displacement spaces are above one Control device with at least three control windows a work connection, a supply connection or a Connectable tank connection. The control unit has a control body in which at least two of the control windows are radial are offset to the displacement rooms.

LIST OF REFERENCE NUMBERS

1

hydrotransformer

2

drum

4

bore

6

displacement

8th

displacer

10

sloping surface

12

swash plate

14

axial bore

16

control body

18

control window

20

control window

22

control window

24

diagonal web

26

Stege

28

Stege

30

radial channel

32

Stege

34

Stege

36

Stege

38

Transition breakthroughs

40

Transition breakthroughs

42

axial

Claims (10)

Hydrotransformer with a rotor (2), in the displacement spaces of which displacers (6) are guided, which are supported on a lifting element (12) for controlling a lifting movement, and with a control device (16, 32) with at least three control windows (18, 20, 22), which are connected to a supply connection (P), a working connection (A) or a tank connection (T) and which can alternately be brought into overlap with the displacement spaces (8) accommodating the displacers (6), the pressure ratio being changed the effective control lengths (1) of the control windows (18, 20) can be adjusted, characterized in that the control device has a control body (16) in which at least two control windows (18, 20) are formed which are offset radially to the displacement spaces (8), which are connected to the displacement chambers (8) via connecting channels (30) and the geometry of which is selected such that the effective control length (1) of the control window (18, 20) at a V creation of the control body (16) can be changed in opposite directions. Hydrotransformer according to claim 1, wherein the Control body (16) in the axial direction with respect to the rotor (2) is slidable. Hydrotransformer according to claim 2, wherein the Control body (16) in an axial bore (14) of the rotor (2) is performed. Hydrotransformer according to claim 2 or 3, wherein the two control windows (18, 20) through a control recess are formed with a diagonal web (24). Hydrotransformer according to claim 4, wherein the Diagonal web (24) is helical. Hydrotransformer according to one of the preceding claims, wherein pressure equalization pockets in the control body (16) to compensate for the in the control windows (18, 20) acting pressure are formed. Hydrotransformer according to claim 6, wherein the Pressure compensation pockets diametrically or axially offset to the control windows (18, 20) are arranged. Hydrotransformer according to one of the preceding claims, the one assigned to the working connection (A) Control window (22) formed on the control body (16) is. Hydrotransformer according to one of claims 1 to 7, wherein the control window assigned to the working connection (A) (22) on an end control disc (32) is formed, in which also two the tank connection (T) and the supply connection (P) associated transition breakthroughs (38, 40) are formed. Hydrotransformer according to one of the preceding claims, this in axial piston design or in radial piston design, preferably as a vane unit is executed.

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