DE102008060596A1 - Hydraulic transformer for hydrostatic drive system, has set of displacement bodies guided in rotor and designed as radial pistons, where pressurizing medium inflow and - outflow take place at spaces by rotor axle - Google Patents

Abstract

The transformer (18) has a displacement body area (44) connected during rotation of a rotor (76) with a motor-sided inlet channel (62), motor-sided drain channel (64), pump-sided pump inlet channel (66) and a pump-sided drain channel. A set of displacement bodies (40) is guided in the rotor and designed as radial pistons, where pressurizing medium inflow and - outflow take place at spaces (54, 56, 58, 60) by a rotor axle (43). The inlet channel, drain channel, pump inlet channel and a consumer channel (68) are arranged in the axle. End sections of the bodies are supported at a cam ring (38).

Description

The The invention relates to a hydraulic transformer according to the Preamble of claim 1.

One Hydrotransformer is a unit in which by hydraulic Coupling of a hydraulic motor and a pump an energy flow Q1 × p1 is converted into an energy flow Q2 × p2. It becomes one existing pressure supply only so much hydraulic energy taken as required to drive a consumer connected to the pump is.

The US 3,188,963 shows a designed as a swash plate machine hydraulic transformer in which in a rotatable cylinder guided displacers are supported on a fixed swash plate. The angle of attack of the swash plate determines the piston stroke of the displacer. The pressure medium supply and / discharge takes place via a control disk with four control units, wherein one control pair of steerers is assigned to the motor or the pump.

From the WO 9731185 A1 is the so-called INNAS hydrotransformer known in which the transmission ratio, ie the ratio between the inlet pressure and the pressure to supply the consumer provided variable. For this purpose, a control level is provided with three control, whose relative position to the dead center of the displacer is variable by turning against the swash plate of an axial piston.

In the US 3,079,864 discloses a hydrotransformer in flight cell construction. In this solution, a plurality of displaceable in the radial direction displacers are mounted in a rotor and biased against a cam ring. The pressure medium supply and removal takes place similar to the above-described solution via an end face arranged control disc.

In the DE 101 90 888 T5 a vane-type hydrotransformer is shown, in which the transmission ratio is variable by relative displacement of the rotor to the lifting ring.

adversely in the axial piston machines described above is that due the necessary control and the expensive storage of the cylinder and the swash plate a comparatively high device engineering effort is required. Furthermore It turned out that these hydrotransformers a considerable noise emission cause, essentially, by the on the swash plate is caused by sliding displacement.

adversely in the hydrotransformers in vane construction in particular, that for guiding and sealing the vane and to guide the wings in the rotor a high constructive effort is required.

In contrast, The invention is based on the object, a simple design To create hydrotransformer.

These Task is accomplished by a hydrotransformer with the characteristics of Claim 1 solved.

Has according to the invention the hydrotransformer has a rotor in which a plurality of displacers are radial slidably guided in each case a displacement is. The remote from the displacement end portions of the Displacers are supported on a cam ring, wherein each displacement chamber during rotor rotation with an engine-side supply channel, an engine-side tank drainage channel, a Pump-side tank inlet channel and a pump-side working channel are connectable. According to the invention, the displacers designed as a radial piston, wherein the pressure medium inflow and pressure fluid discharge through a shaft bearing the rotor shaft section through.

Of the Effort to guide and seal the radial piston in Rotor is opposite to the solutions mentioned above relatively low, wherein forth by the supply of pressure medium from the rotor axis an external piping or wiring is not required is, so that the hydrotransformer with a opposite the solutions described above very little effort can be realized. An advantage over the axial piston units exists in that no rolling bearings are required.

at a preferred embodiment lead to a Supply channel, an engine drain channel, a pump inlet channel and a working channel in an engine intake space or engine drain space or a pump inlet space or a consumer space, respectively in pressure medium connection with several of the displacement chambers stand.

These Solution is characterized by an extremely compact structure, since the displacers associated Pressure chambers are also formed in the rotor axis.

at a variant of the invention is the engine drain space connected to the consumer space - this is a hydrotransformer created with variable displacement motor and constant pump, where the consumer pressure (Load pressure) corresponds to the maximum supply pressure.

These Connection between the engine drain and the consumer compartment can internally, d. H. inside the rotor or externally over a connecting line with valve control done, so this Connection then either locked or aufsteuerbar.

at a particularly simple construction embodiment is the connection between the engine drain space and the consumer space through formed a diagonal channel of the rotor axis.

Of the Construction of the hydrotransformer is further simplified when the Rotor an annular displacement housing has, which is mounted on the rotor axis.

there The above-mentioned channels are preferably in the Rotor axis arranged.

The Production is particularly easy when the channels are distributed on a common circle and at least in sections parallel to the axis.

Of the Device-technical effort is further simplified if the mentioned spaces (engine intake room, engine drain space, pump intake room, Consumer space) are formed by flattening the rotor axis, so that the rooms each have an inner circumferential wall the annular displacer housing and are limited by the flattening.

at In a particularly preferred embodiment, the gear ratio the hydrotransformer made adjustable, the relative position of cam and rotor is relatively adjustable. In this case, the cam ring or the rotor can be adjusted. In this Hubringsteuerung lie the Umsteuerpunkte always in the top or bottom dead center, so that the reversal much more continuous than in the beginning described INNAS hydrotransformer takes place at which the Umsteuerpunkte are changed by adjustment of the control animals.

there a pump-side radius of the cam ring can be designed so that he in an end position coaxial with the rotor outer diameter runs.

Of the Hubring of the hydraulic transformer is according to a Embodiment seen in the axial direction with a executed in approximately elliptical extent.

preferred Embodiments of the invention are described below explained in more detail with reference to schematic drawings. Show it:

1 a hydrostatic drive system for an injection molding machine with a hydraulic transformer;

2 an embodiment of a hydraulic transformer for the drive system 1 and

3 a further embodiment of a hydraulic transformer for the drive system according to 1 ,

In 1 is a mold closing plate of a plastic injection molding machine with the reference numeral 10 designated. This mold-closing plate is guided in a manner not shown on a frame of the plastic injection molding machine and by a hydraulic cylinder 11 traversable. This is designed as a differential cylinder and has one in a cylinder housing 12 guided piston 13 , with a piston rod 14 about which the mold closing plate 10 is pressed. By the piston 13 is the cylinder housing 12 in a piston rod-side pressure chamber 15 and a bottom-side cylinder chamber 16 divided.

The hydraulic cylinder 11 is part of a hydrostatic drive system, which has a secondary controlled subsystem and essentially by a pressure line 17 with an applied pressure and by a hydrotransformer 18 is marked. Pressure medium source is a hydraulic pump 19 that by a drive motor 20 is driven and sucks pressure medium from a tank and into the pressure line 17 emits. The hydraulic pump 19 is executed in the illustrated embodiment with a constant displacement. The delivery of the pressure medium in the pressure line 17 via a check valve 26 that to the hydraulic pump 19 locks out.

At the pressure line 17 is a hydraulic accumulator 24 connected, can be compensated by the pressure medium fluctuations.

To the pressure connection of the hydraulic pump 19 is a simplified illustrated accumulator charging valve 27 connected, in the opening direction on a control surface 28 from the pressure in the pressure line 17 is acted upon and that by means of a spring 29 is biased in a closed position. The output of the accumulator charging valve 27 is with the tank 25 connected. The storage loading valve 27 is closed as long as the pressure in the hydraulic accumulator 24 at the control area 28 generated force is smaller than the force of the compression spring 29 , The hydraulic pump 19 then promotes pressure medium in the pressure line 17 and in the hydraulic accumulator 24 , The storage loading valve 27 opens when the accumulator pressure on the accumulator charging valve 27 set maximum value has reached, so that the hydraulic pump 19 in almost unpressurized circulation to the tank promotes. As soon as the accumulator pressure has dropped below a preset minimum value, the accumulator charging valve closes 27 ,

The hydrotransformer 18 belongs to the secondary regulated subsystem, since pressure medium from the pressure line 17 to the tank 25 drain and from this into the pressure line 17 can be promoted.

In the illustrated embodiment, the hydrotransformer 18 schematically with two over a shaft 23 or directly coupled hydraulic machines 30 . 31 shown, both of which can work in principle as hydraulic pumps and after reversal of direction as hydraulic motors. The with the reference number 30 illustrated hydromachine is the secondary unit of the secondary controlled subsystem, wherein a pressure port 32 with the pressure line 17 and a tank connection 33 with the tank 25 connected is. A pressure connection 34 the hydraulic machine 31 is over a line 36 with the bottom-side cylinder chamber 16 connected to the hydraulic cylinder. A tank connection 35 the hydraulic machine 31 is with the tank 25 connected.

The two hydraulic machines 30 . 31 Both can be designed with adjustable displacement, whereby the adjustment of the hydraulic machines 30 . 31 then done in reverse. In another, also described below embodiment, the hydraulic machine 30 (Engine) with adjustable displacement while the hydraulic machine 31 (Pump) is designed with a constant delivery volume.

The schematic structure of such hydrotransformers will be described with reference to 2 and 3 explained.

In the case of the 2 and 3 illustrated embodiments, the hydraulic transformer is designed in radial piston construction, wherein the motor-side hydraulic machine 30 and the pump-side hydraulic machine 31 are integrated together in a radial piston unit.

Such a radial piston unit has a housing, not shown, of the hydraulic transformer 18 mounted cam ring 38 on which a variety of radial pistons 40 is supported. These are in an annular displacement housing 42 guided in the radial direction adjustable. The from the lifting ring 38 repellent face of each radial piston 40 limits a displacement space 44 which is during the rotation of the displacer housing 42 depending on the stroke of the displacer 40 changed. The annular displacer housing 42 is on a stationary rotor axis 43 stored. As can be seen from the schematic illustration, this rotor axis is 43 in the area of the displacement rooms 44 with four flattenings 46 . 48 . 50 . 52 executed, with the inner peripheral surface (dash-dotted) an engine intake chamber 54 , an engine drain 56 , a pump room 58 and a consumer room 60 limit. The engine intake room 54 is via an inlet channel 62 with the pressure line 17 , the engine drain space 56 via a drainage channel 64 with the tank connection 33 , the pump room 58 via a pump inlet channel 66 with the other tank connection 35 and the consumer-side consumer space 60 via a consumer channel 68 and the pressure connection 34 with the cylinder room 16 of the hydraulic cylinder 11 leading line 36 connected.

As shown in 2 the four channels run 62 . 64 . 66 . 68 paraxial and lie approximately on a common pitch circle, being tangential in the associated spaces 54 . 56 . 58 . 60 open out. Of course, the channel guide can also be chosen in other ways.

The inner peripheral surface of the cam ring 38 forms a cam ring control surface 70 out in the presentation according to 2 Viewed in the axial direction has approximately the shape of an ellipse with circular arc-shaped end face sections, the two sides on tangential surfaces 72 . 74 connected to each other. The radius of the two end faces is in 2 marked with R.

In the illustration according to 2 is the out of the displacer housing 42 and the rotor axis 43 existing rotor 76 eccentric to the symmetry axis of the cam ring 70 arranged. This measure of eccentricity is in 2 marked with e. According to the invention, this eccentricity e can be changed by an adjusting mechanism, not shown, wherein the lifting ring 38 is adjusted in the direction indicated by the double arrow. In the in 2 shown left end position is the axis of the rotor 76 coaxial with the radius of curvature R of the left end face of the cam ring 70 so that in this case no promotion takes place. The radius of the displacer housing 42 is smaller than the radius R, so tangential always a gap 77 remains. By adjusting the eccentricity e, the delivery or the displacement of the engine part (right in 2 ) or the pump part (left in 2 ) of the hydrotransformer 18 adjusted in opposite directions - the hydrotransformer is thus formed by an adjusting motor and a variable displacement pump, with an increase in the absorption volume is then accompanied by a corresponding reduction in the delivery volume. The pressures that can be generated on the consumer side are then calculated in a first approximation from the equation mentioned at the outset: Q1 × p1 = Q2 × p2

As usual with radial piston machines, the radial pistons are located 40 not directly on the cam ring control surface 70 but are with roles 78 provided the friction between Hubringsteuerfläche 70 and radial pistons 40 minimize. Such roles are known from the prior art, is exemplified in the DE 41 43 152 C2 directed.

At the in 2 shown solution are each at least four displacement chambers 44 to each one of the rooms 54 . 56 . 58 . 60 open accordingly - then operate at least four displacement units in the same mode (engine inlet drain, pump inlet, -flow), the flats are designed such that the reversal between the individual rooms (engine inlet, engine outlet, pump inlet, pump outlet) each in the dead centers the radial piston 40 be redirected. These dead points are located in the illustration according to 2 in each case in the horizontal and the vertical.

D. H. In this solution, the reversal is independent from the set eccentricity e.

According to the embodiment 2 the hydraulic transformer is designed on the motor side and on the pump side with counter-adjustable displacement / delivery volume. 3 shows a variant in which the hydrotransformer 18 on the motor side with adjustable displacement and on the pump side with constant displacement. The basic structure of this hydrotransformer 18 equals that of 2 , So that for the sake of simplicity, only the different components are explained and incidentally to the comments 2 is referenced.

In the embodiment according to 3 are the engine drain space 56 and the consumer room 60 over one of the two channels 64 . 68 connecting diagonal channel 78 connected to each other, so that in the engine cycle the consumer pressure is pending. By means of this solution, a fixed-displacement pump is thus obtained on the pump side, while an adjusting motor is present on the motor side (as in the exemplary embodiment according to FIG 2 ), whose displacement is adjustable via the eccentricity e.

In the variant according to 3 is the connection between the consumer space 60 and the engine drain space 56 internally, ie via the diagonal channel 78 the wave 23 educated. In principle, one could also the embodiment according to 2 Modify in the manner described above by externally a connecting line is provided, which can be shut off or opened, for example via a valve, wherein in the open state of this control valve, the discharge side of the engine 30 with the consumer side of the pump 31 connected is. This external connection is in 1 indicated by dashed lines, wherein the switching valve by the reference numeral 80 is provided. Depending on the switching position of the valve 80 the hydrotransformer works according to the execution 2 or the execution after 3 ,

In the embodiments with internal / external connection of the rooms 56 . 60 However, the consumer load pressure must not be higher than the supply pressure, ie the pressure in the engine intake chamber 54 is applied.

Of the Advantage of the above-described circuit over conventional Solutions for controlling cylinders via the known systems "Load Sensing", "Flow Matching "and" LUDV "(load independent Flow distribution) is that in these conventional Concepts of supply pressure is throttled while when using circuits with hydrotransformer the hydraulic cylinder from a constant pressure network essentially without throttle losses a valve control can be operated.

Disclosed is a hydrotransformer in radial piston construction, in which the Pressure medium supply and removal takes place internally through a rotor axis.

10

plastic injection molding machine

11

hydraulic cylinders

12

cylinder housing

13

piston

14

piston rod

15

annulus

16

cylinder space

17

pressure line

18

hydrotransformer

19

hydraulic pump

20

drive motor

23

wave

24

hydraulic accumulator

25

tank

26

check valve

28

control surface

29

feather

30

engine

31

pump

32

pressure connection

33

tank connection

34

pressure connection

35

tank connection

36

management

38

lifting ring

40

radial piston

42

displacer

43

rotor axis

44

displacer

46

flattening

48

flattening

50

flattening

52

flattening

54

Engine inlet chamber

56

Motor drain space

58

Pump inlet space

60

consumer space

62

inlet channel

64

drain channel

66

Pump inlet channel

68

consumer channel

70

Hubringsteuerfläche

72

tangential

74

tangential

76

rotor

77

gap

78

Diagonal channel

80

switching valve

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 3,188,963 [0003]
• WO 9731185 A1 [0004]
• - US 3079864 [0005]
• - DE 10190888 T5 [0006]
• - DE 4143152 C2 [0042]

Claims (13)

Hydrotransformer with a rotor ( 76 ), in which a large number of displacers ( 40 ) is guided, whose from the displacer ( 44 ) removed end portions on a cam ring ( 38 ) are supported and with a rotor ( 76 ) bearing rotor axis ( 43 ) each have a displacer space ( 44 ), which during the rotor rotation with a motor-side inlet channel ( 62 ), a motor-side drainage channel ( 64 ), a pump-side pump inlet channel ( 66 ) and a pump-side drainage channel ( 66 ) is connectable, characterized in that the displacer radial piston ( 40 ) and the pressure medium inflow and outflow to the rooms ( 54 . 56 . 58 . 60 ) through the rotor axis ( 43 ) through. Hydraulic transformer according to claim 1, wherein the inlet channel ( 62 ), the drainage channel ( 64 ), the pump inlet channel ( 66 ) and the consumer channel ( 68 ) in the rotor axis ( 43 ) are arranged and in an engine intake room ( 54 ) or a motor drain space ( 56 ) or a pump intake space ( 58 ) or a consumer space ( 60 ), which in each case in pressure medium connection with several of the displacement chambers ( 44 ) stand. Hydraulic transformer according to claim 2, wherein the engine drain space ( 56 ) with the consumer space ( 60 ) connected is. Hydraulic transformer according to claim 3, wherein the pressure fluid connection internally through the rotor axis ( 43 ) through. Hydraulic transformer according to claim 3, wherein the pressure medium connection takes place externally and by means of a switching valve ( 80 ) can be shut off. Hydraulic transformer according to claim 4, wherein one of the two spaces ( 56 . 60 ) connecting channel as a diagonal channel ( 78 ) is trained. Hydraulic transformer according to one of the preceding claims, wherein the rotor ( 76 ) a rotor axis ( 43 ), to which an annular displacement housing ( 42 ) is attached. Hydraulic transformer according to one of claims 2 to 7, wherein the channels ( 62 . 64 . 66 . 68 ) in the rotor axis ( 43 ) are arranged. Hydraulic transformer according to claim 7 or 8, wherein the channels ( 62 . 64 . 66 . 68 ) are distributed on a common pitch circle and at least partially parallel to the axis. Hydraulic transformer according to claim 8 or 9, wherein the spaces ( 54 . 56 . 58 . 60 ) by flattening ( 46 . 48 . 50 . 52 ) of the rotor axis ( 43 ) are formed. Hydraulic transformer according to one of the preceding claims, wherein the lifting ring ( 38 ) and the rotor ( 76 ) are adjustable relative to each other for adjusting the swallow / delivery volume. Hydraulic transformer according to claim 11, wherein a pump-side radius (R) of the cam ring ( 38 ) is designed so that it runs in a relative position coaxial with the rotor outer diameter. Hydraulic transformer according to claim 12, wherein the lifting ring ( 38 ) seen in the axial direction has an approximately elliptical circumference.