DE102012001562A1 - Valve arrangement for a mobile work machine - Google Patents

Abstract

Disclosed is a valve arrangement for a mobile work machine with a metering or control valve, via which a regenerable connection and a further connection of a consumer -. B. cylinder or motor - the mobile machine can be supplied. There is a - preferably separate - regeneration valve with only two switch positions (fully open, fully closed) provided over the pressure medium from the regenerable connection in a tank can be derived. Above a predetermined pressure difference between the terminals, the regeneration valve is open and otherwise closed. A main or spool of the control valve has a common regeneration and working position. The spool thus has no along a displacement path of the spool from the regeneration position spaced working position, so that no active switching between working and Regernationsbetrieb is necessary.

Description

The invention relates to a valve arrangement for a consumer of a mobile machine with a regeneration position according to the preamble of patent claim 1.

In one application example, a differential cylinder of a handle of an excavator is supplied via such a valve arrangement. About a pressurization of a piston bottom side of the differential cylinder in a working position of the valve assembly, a lowering movement of the stem with a blade and thus a grave movement. By means of a reversal position of the valve arrangement, a pressure is applied to an annular surface side of the differential cylinder and thus a lifting of the stem.

When pulling or Vorsteilender load on the stem by the weight of oil is conveyed via a regeneration position of the valve assembly oil from the annular surface side of the differential cylinder directly to the piston surface side, so that the pump has to deliver less oil. The corresponding delivery pressure is generated by the load on the piston. In the working position (digging) with the same direction of movement, the oil is discharged from the ring surface side into the tank.

The pamphlets DE 10 2009 021 831 A1 and JP 2002-061605 A show a valve assembly in which a separate regeneration slide is provided for regeneration. This causes the switching between working and regeneration automatically and depending on the pressure on the piston surface side. The Regerationsschieber adjusted a continuously variable throttle point, so that a soft transition between working and regeneration position is given.

The DE 10 2006 002 920 A1 discloses a valve arrangement in which the working and the regeneration position are separate switching positions of a single spool, which must be actively switched from the outside.

The present invention aims to provide a valve assembly in which the switching between regeneration and working automatically and which is done. In this case, vibrations of the regeneration slide, in particular in the working position, should be avoided.

This object is achieved by a valve arrangement for a mobile work machine having the features of patent claim 1.

The valve arrangement according to the invention has a metering or control valve, via which a regenerable connection and a further connection of a consumer -. B. cylinder or engine - a mobile machine can be supplied. There is a - preferably separate - regeneration valve with only two switch positions (fully open, fully closed) provided over the pressure medium from the regenerable connection in a tank can be derived. Above a predetermined pressure difference between the terminals, the regeneration valve is open and otherwise closed. A main slide or control slide of the control valve has a common regeneration and working position. The spool thus has no along a displacement path of the spool from the regeneration position spaced working position. In the valve arrangement according to the invention, the switching between regeneration and working position is soft and automatic. In this case, vibrations of the spool are avoided by its common regeneration and working position.

The mobile working machine whose consumer is connected to the valve arrangement according to the invention may be a backhoe loader or a compact excavator or a mini-excavator or a telescopic loader. In these machines, regeneration of the limited energy reserves is particularly advantageous.

Further advantageous embodiments of the invention are described in the dependent claims.

In a particularly preferred embodiment of the valve arrangement according to the invention, the spool in the control valve - preferably hydraulically - continuously adjustable. This allows an operator of the mobile machine steplessly steer the consumer. This results in an area at a displacement of the control slide along its longitudinal axis with a plurality of working positions and thus common regeneration positions.

In a preferred embodiment, the Regerationsventil is a pilot-operated check valve, which is controlled directly with a tapped from the other terminal acting in the opening direction control pressure. This ensures that the check valve remains closed during regeneration operation and that no pressure medium flowing back from the regenerable connection can flow to the tank via the check valve. Thus, the entire pressure medium flowing back from the regenerable connection flows to the control valve for regeneration. As soon as the force pulling on the consumer changes into an opposing force, that is to say a change of direction of the external force takes place at the consumer, the working mode is detected and the check valve opens. Thus, that of the regenerable connection flowing back through the check valve with minimal resistance to the tank.

In a preferred embodiment of the check valve whose closing spring has low spring stiffness, so that virtually no intermediate position can be set.

In a first and second application example, the consumer, which can be supplied by the valve arrangement according to the invention, a differential cylinder.

It can according to the first application example -. B. in a stick cylinder of an excavator - the annular space of the differential cylinder to be connected to the regenerable terminal.

In this case, it is preferred if the regeneration valve has an opening area and a shooting area, wherein the closing area is smaller than the opening area.

Preferably, the ratio closing surface / opening area corresponds approximately to the ratio ring surface / bottom surface of a piston of the differential cylinder.

According to the second application example -. As in a boom cylinder of an excavator - the bottom space of the differential cylinder may be connected to the regenerable terminal.

In this case, it is preferable if the regeneration valve has an opening area and a shooting area, wherein the closing area is greater than the opening area. Preferably, the ratio opening area / closing surface corresponds approximately to the ratio ring surface / bottom surface of a piston of the differential cylinder.

In a third application example, the consumer, which can be supplied by the valve arrangement according to the invention, is a synchronous cylinder.

It is preferred if the regeneration valve has an approximately equal opening area and shooting area.

In all application examples, the opening area and the shooting area can be arranged on two different valve bodies (eg, closing body and opening piston) of the regeneration valve, which can be brought into contact with one another.

In a particularly preferred further development of the valve arrangement according to the invention, a regeneration line is opened in or in the common regeneration and working position (s), in which a non-return valve opening from the regenerable to the further connection is arranged.

In or on the Regerationsleitung can be arranged an adjustable throttle. Preferably, the throttle is adjustable via the displacement path or the position of the spool in the control valve.

Depending on the application example, it is advantageous if the regenerable connection is connected to the tank via the common regeneration and working position (s) of the spool valve via a throttled drain. This throttled process is important in a regeneration according to the second application example (eg boom cylinder) to dissipate the excess volume. During a regeneration according to the first application example (for example, a stick cylinder), the throttled outflow can discharge pressure medium which is not to be regenerated.

In a device-technically simple embodiment of the throttled drain or its throttle is formed on the spool of the control valve.

In the following, an embodiment of the invention (with two application examples) will be described in detail with reference to FIGS. Show it:

1 the embodiment of the valve assembly according to the invention with a first application example in a schematic representation;

2 the regeneration valve of the valve assembly according to 1 in a sectional view;

3 the control valve of the valve assembly according to 1 in a sectional view;

4 the control valve according to 3 in the regeneration mode with the first and with a second application example; and

5 the control valve according to 3 in working mode with the first and the second application example.

1 shows the embodiment of the valve assembly according to the invention. This consists essentially of a control valve 1 and as a lockable shut-off or check valve 2 trained regeneration valve. The valve arrangement 1 . 2 is via a pump port P to a variable displacement pump 4 and via a tank connection T to a tank 6 connected. The valve arrangement 1 . 2 serves (according to the in 1 shown first application example) for the supply of a differential cylinder 8th and is via a regenerable port C2 to an annulus 10 and via another connection C1 to a floor space 12 of the differential cylinder 8th connected. The differential cylinder 8th serves (at the in 1 shown application example) for actuating a (not shown) stem of an excavator. Pressurization of the floor space 12 leads to a lowering of the stem and a (also not shown) blade. This function is used in particular for digging. A pressurization or supply of the annulus 10 lead to a lifting of the stem and the blade. For appropriate activation and metering of a pressure medium flow from the variable displacement pump 4 to the respective port C1 or C2 is the control valve 1 , which is designed as a continuously adjustable 4/3-way valve. In the (in 1 shown) spring-biased basic position 0 a spool 14 are the connections A, B shut off. In a working position a, which is also a regeneration position, the pump port P is connected to the working port B and thus the further port C1 and thus the floor space 12 pressurized with pressure medium. In a further working position b, the pump port P is connected to the working port A and thus the port C2 and thus the annulus 10 pressurized with pressure medium.

In the common regeneration and working position a of the spool valve 14 a pressure medium connection from port A to port B is provided, via which the regeneration takes place. In this pressure medium connection is a non-return valve opening from port A to port B. 16 and a throttle 18 provided, the opening cross-section of the position or position of the spool 14 is adjustable.

The pilot operated check valve 2 has a valve body 20 and a tank port T, wherein in a normal or working operation of the valve arrangement according to the invention 1 . 2 a connection from the port C2 to the tank port T is opened, while in the regeneration operation, the connection from the port C2 to the tank port T through the valve body 20 is locked. For this function has the check valve 2 a control line 22 , which at one the further connection C1 with a connection V1 of the check valve 2 connecting work line section 24 connected.

2 shows the structural design of the pilot operated as a check valve 2 trained regeneration valve of the valve assembly according to 1 , It has an inlet, which is connected to the regenerable port C2, and a drain or tank port T. Furthermore, connects the check valve 2 the further connection C1 and the connection V1, between which the working line section 24 is trained. Through this flows depending on the setting of the control valve 1 (see. 1 ) Pressure medium from this to the floor space 12 of the differential cylinder 8th (see. 1 ) or the other way around. The check valve 2 has a socket 26 in a housing 28 is screwed in, and in the valve body 20 by a closing spring 30 is biased in a closing direction. In the in 2 illustrated closed position of the valve body 20 is a connection from the regenerable port C2 to the tank port T shut off, so that a regeneration of the annulus 10 displaced pressure medium via the main valve 1 is possible. Also in the closing direction of the valve body 20 the pressure prevailing at the regenerable port C2 acts. The opposite in an opening direction of the valve body 20 the pressure prevailing at the further connection C1 acts. For this purpose, an acting in the opening direction control pressure chamber 31 over the control line 22 and over the work line section 24 connected to the other terminal C1. The control pressure chamber 31 is from an opening area 33 an opening piston 32 limited, in abutment with the valve body 20 can be brought and then depending on the working pressure at the other terminal C1 the valve body 20 subjected to an opening force.

• • ein erster Tankdruckraum 36;
• • ein mit dem Arbeitsanschluss A verbundener Druckraum 38;
• • ein erster mit einem Brückenkanal 40 verbundener Brücken-Druckraum 42;
• • ein mit dem Pumpenanschluss P verbindbarer Zumess-Druckraum 44;
• • ein mit dem Pumpenanschluss verbundener Pumpen-Druckraum 46;
• • ein zweiter mit dem Brückenkanal 40 verbundener Brücken-Druckraum 48;
• • ein mit dem Arbeitsanschluss B verbundener Druckraum 50; und
• • ein zweiter Tank-Druckraum 52.

3 shows the control valve 1 the valve assembly according to 1 in a cut view. His spool 14 is (as in 1 ) in a medium basic position 0 shown in which the two working ports A, B, the pump port P and the tank port T are shut off. The control valve has (in 3 from left to right) along a longitudinal axis 34 the following pressure chambers:

• • a first tank pressure room 36 ;
• • a pressure chamber connected to the working port A. 38 ;
• • a first with a bridge channel 40 connected bridge pressure chamber 42 ;
• • a Zumess pressure chamber which can be connected to the pump connection P. 44 ;
• • a pump pressure chamber connected to the pump connection 46 ;
• • a second with the bridge channel 40 connected bridge pressure chamber 48 ;
• • a pressure chamber connected to the working port B 50 ; and
• • a second tank pressure chamber 52 ,

The bridge canal 40 connects the Zumess pressure chamber 44 via a load-holding valve 54 with the two bridge pressure chambers 42 . 48 , Inside the spool 14 is the check valve 16 (see. 1 ) arranged. This has at least a first radial bore 58 and at least a second radial bore 62 , The check valve 16 opens at a flow from the first radial bore 58 to the second radial bore 62 while, conversely, predominantly pressurizing via the second radial bore 62 closes. This is a valve body or control piston 60 the check valve 16 in a longitudinal bore of the spool 14 movably arranged and by a closing spring 64 in the (in 3 shown) biased closed position. The control piston 60 has a radially recessed portion whereby the longitudinal bore an annular space 66 is formed, always with the first radial bore 58 connected is. At the radially recessed area of the control piston 60 is still a sealing section 68 attached in the (in 3 shown) closed position of the control piston 60 a connection from the second radial bore 62 for radial drilling 58 shuts off. During a movement of the control piston 60 with the sealing section 68 (in 3 ) to the right against the force of the closing spring 64 becomes the connection of first radial bore 58 to the second radial bore 62 open. The control piston 60 the check valve 16 is over a longitudinal bore 63 and via a radial pressure detection bore 65 acted upon by the pressure at the working port B. This admission takes place when the pressure detection bore 65 with the pressure room 50 is associated. This is done by an adjustment of the spool 14 (in 3 ) to the left in the common regeneration and working position a. In this position a, which in the 4 and 5 is shown, closes the check valve 16 when the pressures at the working ports A and B are about the same.

The adjustable throttle 18 (see. 1 ) is through the second radial bore 62 and one at the first bridge pressure chamber 42 arranged control edge 70 educated.

To connect the working port A to the pump port P and the working port B to the tank port T, the spool 14 in 3 to the right into working position b (cf. 1 ) postponed. As a result, a connection from the pump port P via the pump pressure chamber 46 , via a metering orifice 56b , the Zumess pressure chamber 44 , the load-holding valve 54 , a section of the bridge canal 40 , the first bridge pressure chamber 42 , and the pressure room 38 made to the working connection A.

In the 1 shown common regeneration and working position a of the control valve 1 is due to a shift of its spool 14 (in 3 to the left).

4 shows the control valve 1 the valve assembly according to the invention 1 . 2 according to 3 in regeneration mode. This is with the (in 4 shown) common regeneration and working position a of the spool 14 reached. These are in 4 the first application example with the differential cylinder 8th and a second application example with a differential cylinder 108 shown. The first application example is from the annulus 10 of the differential cylinder 8th Pressure medium for regeneration via the regenerable port C2 displaced to the working port A, while in the second application example pressure medium from a floor space 112 of the differential cylinder 108 is displaced to the working port A via the regenerable port C2.

In both application examples, the pressure medium flows over the first radial bore 58 , inside the spool 14 arranged annulus 66 , The pressure medium continues to flow over the open check valve 16 , via the adjustable throttle 18 and over the bridge canal 40 for connection B. It can in the first application example with the differential cylinder 8th the entire out of his annulus 4 displaced pressure medium to be regenerated. Contrary to the second application example with the differential cylinder 108 not the entire pressure medium of the floor space 112 be regenerated, since the annulus 110 can not absorb the appropriate amount of pressure medium. Therefore, between the pressure chamber 38 and the first tank pressure room 36 a throttled drain ST to the tank T provided. This one has a on the spool 14 formed groove.

The throttled drain ST serves to divert at least the excess from the floor space 112 displaced pressure medium.

If in the in 4 shown position, the pressure on the regenerable port C2 decreases or if in the in 4 shown position, the pressure at the terminal C1 increases, and in particular when approximately balanced pressure conditions at the check valve 16 prevail, then closes the check valve 16 about his closing spring 64 , This ends the regeneration.

5 shows the control valve 1 the valve assembly according to the invention 1 . 2 according to 3 in normal or working mode. This is also by the in 4 shown regeneration and working position a of the spool 14 reached. The pressure medium flows from the pump pressure chamber 46 , via the Zumess pressure chamber 44 , about (in 5 ) right section of the bridge channel 40 and over the pressure room 50 to the working connection B. The case of the variable displacement pump 4 (see. 1 ) conveyed pressure medium continues to act on the (in 5 ) left section of the bridge channel 40 and over the throttle 18 inside the spool 14 formed check valve 16 , whereby this is closed.

The directional control valve or control valve 1 is with a Regerations control slide 14 equipped. The cross section of the throttled drain ST serves to relieve pressure at the moment of load reversal. The hydraulically controlled check valve 2 is the first application example with the regenerable annulus 10 between the rod side and the annulus 10 and the bottom side or the floor space 12 of the differential cylinder 8th arranged. As long as the load of equipment on the rod of the differential cylinder 8th pulls, remains the check valve 2 closed. As soon as the differential cylinder 8th when the tensile force reverses into a compressive force and the pressure on the bottom side becomes greater than on the side of the rod, the non-return valve opens 2 the rod side to the tank T and the pressure force of the cylinder bottom is available as a worker.

A switch is in the spool valve 14 of the control valve 1 integrated. In neutral position 0 of the spool 14 is that of the recorded therein control piston 60 not connected to the pump port P and the working ports A, B, so it has no influence on the internal leakage, since it is connected downstream of the closed control edges.

In 4 with the first application example is the spool 14 in the position "cylinder extension" a and at the differential cylinder 8th Due to the weight of the equipment, it has a pulling load. The bar-side pressure thus results from the towing load plus the ground pressure increased by the area ratio. Thus, the pressure prevailing in port A is higher than the pressure in port B. The control piston 60 So it is against the closing spring 64 held in the illustrated position and the total displaced from the rod side flow is on the bottom side of the differential cylinder 8th directed. For the same positioning speed is less flow from the variable displacement pump 4 needed.

In 5 With the first application example, a digging position is shown in which the soil resistance increases and the pressure difference between the working ports A, B decreases. The smaller pressure difference leads to a reduction in the volume flow from the working port A to the working port B, the movement becomes slower the greater the grave resistance becomes. Reaches the pressure difference through the closing spring 64 given value, it shifts the control piston 60 , In this second position of the control piston 60 the regeneration connection is interrupted from the working port A to the working port B and the rod side is connected to tank T, that is, on the rod side no back pressure is generated and the differential cylinder 8th can extend with maximum power against the soil resistance.

The boom of the compact excavator, the mast of the loader and the boom of the telescopic loader are of pressure cylinders according to the in 4 shown second application example operated. When lowering or retracting the differential cylinder 108 More oil is displaced on the bottom side than the rod side can absorb. Also in this case, the regeneration circuit according to the invention can be applied to lower almost without hydraulic pump power. The excess volume flow, which corresponds to the rod volume is, via control notches of the throttled drain ST from the pressure chamber 38 over the first tank pressure chamber 36 to the tank 6 controlled.

With reference to 5 achieved when lowering the differential cylinder 108 According to the second application example of the working equipment, the ground and the external load are no longer supported on the differential cylinder 108 but off on the floor. Since the pressure difference disappears due to the external load, interrupts the spring-loaded control piston 60 the connection from A to B and connects the bottom-side working port A with tank 6 , A limited volume flow from the pump port P via the orifice D to the working port B causes a reversal of the external load, the work equipment presses on the ground and the machine can be raised.

Notwithstanding the embodiment shown in the figures, in the first application example in which the annulus 10 of the differential cylinder 8th connected to the regenerable port C2 in the spool 14 provided throttled drain ST to the tank 6 omitted. Instead of the throttled drain ST can at the common regeneration and working position a of the spool 14 a shut-off of the return from port A to the tank port T of the control valve 1 be provided. Thus, during regeneration, the entire pressure medium from the annulus 10 via the control valve 1 in the floor space 12 guided.

Instead of in the 3 to 5 shown load holding valve 54 can in the bridge canal 40 a pressure compensator according to the principle of load-independent flow distribution (LUDV) be provided.

Disclosed is a valve arrangement for a mobile work machine with a metering or control valve, via which a regenerable connection and a further connection of a consumer -. B. cylinder or motor - the mobile machine can be supplied. There is a - preferably separate - regeneration valve with only two switch positions (fully open, fully closed) provided over the pressure medium from the regenerable connection in a tank can be derived. Above a predetermined pressure difference between the terminals, the regeneration valve is open and otherwise closed. A main or spool of the control valve has a common regeneration and working position. The spool thus has no along a displacement path of the spool from the regeneration position spaced working position, so that no active switching between working and Regernationsbetrieb is necessary.

LIST OF REFERENCE NUMBERS

1

control valve

2

check valve

4

variable

6

tank

8th; 108

differential cylinders

10; 110

annulus

12; 112

floor space

14

spool

16

check valve

18

throttle

20

valve body

22

control line

24

Working line section

26

Rifle

28

casing

30

closing spring

31

Control pressure chamber

32

opening piston

33

opening area

34

longitudinal axis

36

first tank pressure chamber

38

pressure chamber

40

bridge channel

42

first bridge pressure chamber

44

Zumess-pressure chamber

46

Pump pressure chamber

48

second bridge pressure chamber

50

pressure chamber

52

second tank pressure chamber

54

Load-holding valve

56a, 56b

metering orifice

58

first radial bore

60

switching piston

62

second radial bore

63

longitudinal bore

64

closing spring

65

Pressure signaling hole

66

annulus

68

sealing section

70

control edge

ST

throttled process

C1

further connection

C2

regenerable connection

V1

connection

A

working port

B

working port

D

metering orifice

P

pump connection

T

tank connection

0

initial position

a

Regeneration and working position

b

working position

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009021831 A1 [0004]
• JP 2002-061605 A [0004]
• DE 102006002920 A1 [0005]

Claims (16)

Valve arrangement ( 1 . 2 ) for a mobile work machine with a control valve ( 1 ), via which a regenerable terminal (C2) and a further terminal (C1) of a consumer ( 8th ; 108 ), whereby a regeneration valve ( 2 ) is provided with only two switching positions, via the pressure medium from the regenerable port (C2) in a tank ( 6 ) is derivable, and wherein the regeneration valve ( 2 ) above a predetermined pressure difference between the ports (C1, C2) is open and otherwise closed, and wherein a spool ( 14 ) of the control valve ( 1 ) has a common regeneration and working position (a). Valve arrangement according to claim 1, wherein the spool ( 14 ) in the control valve ( 1 ) is continuously adjustable, and wherein an area at a displacement of the spool ( 14 ) is formed with common regeneration and working positions (a). Valve arrangement according to claim 1 or 2, wherein the Regerationsventil a pilot-operated check valve ( 2 ). Valve arrangement according to claim 3, wherein the check valve ( 2 ) is directly controlled with one of the further terminal (C1) tapped acting in the opening direction control pressure. Valve arrangement according to claim 3 or 4, wherein the check valve ( 2 ) a closing spring ( 30 ) having low spring stiffness. Valve arrangement according to one of the preceding claims, wherein the consumer a differential cylinder ( 8th ), whose annulus ( 10 ) is connected to the regenerable terminal (C2). Valve arrangement according to claim 6, wherein the regeneration valve ( 2 ) an opening area ( 33 ) and a shooting surface, and wherein the closing surface is smaller than the opening area. Valve arrangement according to claim 1 to 5, wherein the consumer a differential cylinder ( 108 ) whose floor space ( 112 ) is connected to the regenerable terminal (C2). The valve assembly of claim 8, wherein the regeneration valve has an opening area and a firing area, and wherein the closing area is greater than the opening area. Valve arrangement according to claim 1 to 5, wherein the consumer is a synchronous cylinder. Valve assembly according to claim 10, wherein the regeneration valve has an opening area and a shooting surface, which are about the same size. Valve arrangement according to one of the preceding claims, wherein in the common regeneration and working position (a) a Regerationsleitung is controlled, in which one of the regenerable port (C2) to the further port (C1) opening check valve ( 16 ) is arranged. Valve arrangement according to claim 12, wherein in or on the Regerationsleitung an adjustable throttle ( 18 ) is arranged. Valve arrangement according to claim 13, wherein the Regerationsleitung with the check valve ( 16 ) in the control slide ( 14 ), and wherein the adjustable throttle ( 18 ) between the spool ( 14 ) and a housing of the control valve ( 1 ) is formed. Valve arrangement according to one of the preceding claims, wherein in the common regeneration and working position (a) of the regenerable port (C2) via a throttled drain (ST) with the tank ( 6 ) connected is. Valve arrangement according to claim 15, wherein the throttled drain (ST) on the spool ( 14 ) of the control valve ( 1 ) is trained.

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