DE102009035216A1 - Slewing drive - Google Patents

Abstract

Disclosed is a hydraulic slewing gear drive for a mobile working device with a pump which is connected to a control directional control valve via a pump line, the pump line being relieved to a tank via an unloading valve. Furthermore, the slewing gear drive has two working lines, via which the control directional valve is connected to a slewing gear motor, whereby at least one further consumer can also be supplied by the pump. According to the invention, if the rotating gear motor acting as a pump is decelerated, pressure medium can be fed into the pump line via at least one pressure connection valve.

Description

The The invention relates to a hydraulic slewing drive for Mobile implements (eg excavators) according to the Preamble of claim 1.

at hydraulic slewing drives is a slewing motor to drive a superstructure or superstructure of a pump via a Directional valve supplied with pressure medium.

at the completion of the rotational movement via a feed of the Directional valve is created as a function of the rotational speed and the mass of the rotated structure or superstructure braking energy. These is usually via the acting as a pump slewing motor and degraded via pressure relief valves, wherein the pressure medium flows back into a tank.

The DE 198 33 489 A1 shows a slewing drive for an excavator, in which both working lines of a slewing motor can be relieved via brake valves to the tank.

adversely At such a turntable drives is that the braking energy is not can be regenerated. Especially with mobile work equipment, whose heavy structure is often rotated and slowed down, arises in this way often considerable energy loss.

In the publication US 6,584,769 discloses a hydraulic circuit, wherein pressure switching valves are arranged between each terminal of the slewing motor and a hydraulic accumulator. The hydraulic accumulator is connected to the consumer-side connection of a hydraulic machine. With this circuit braking energy of the slewing can be stored in the hydraulic accumulator and used by the hydraulic machine.

The publication DE 697 35 941 T2 shows a control device for a construction machine, in which a braking of the slewing takes place via an injection of pressure medium into the pump line. The corresponding pressure medium connection is controlled via a pressure-adjusting valve and opens downstream of a check valve in the pump line. In the area of the mouth, a hydraulic accumulator is connected to the pump line, so that braking energy of the slewing gear can be stored and regenerated.

adversely on the latter hydraulic slewing drives is the device technology Expenditure especially in connection with the hydraulic accumulator and the assigned valve technology.

the In contrast, the invention is based on the object, a Hydraulic slew drive for mobile work tools to create, the regenerative with little device complexity can be slowed down.

These Task is solved by a hydraulic slewing drive according to claim 1.

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

Of the Hydraulic slewing drive according to the invention for a mobile work tool has a pump over a pump line is connected to a control-way valve, wherein the pump line via a Unloadingventil to a tank is relieved. Furthermore, the slewing drive has two working lines, over the control valve is connected to a slewing motor, wherein at least one further consumer can be supplied by the pump is. It can be at a delay of acting as a pump Slewing motor of this via at least one pressure switch valve Pressure medium can be fed into the pump line. This is a regenerative braking of a superstructure or superstructure of the mobile Working equipment possible, with other consumers of the mobile implement with the appropriate pressure medium be supplied additionally.

at a particularly preferred development branches of each work line an opening into the pump line regeneration line from, in each of which a pressure-adjusting valve is provided. This is regenerative braking in both directions of rotation of the slewing motor possible.

One preferred embodiment of the invention Slew drive has two pressure switching valves, with a Zuschaltdruck the pressure switching valves higher than a maximum opening pressure of the unloading valve. This is the moment of opening the respective pressure switching valve, the pressure in the pump line lower than the pressure in the respective working line, so that an outflow of the pressure medium can take place, the thus other consumers of the mobile implement stands.

In a preferred embodiment of this embodiment, the two pressure switching valves are acted upon in the opening direction by the pressure in the connected working line and in the closing direction only by a spring, wherein a spring-side drain connection of each pressure switching valve is connected to the tank. This is an independent of the pressure in the pump line opening behavior of Pressure switch valves guaranteed.

at A preferred embodiment is a bias of the spring over an adjustable acted upon by a control pressure adjusting piston adjustable. Thereby can be an operator or driver of the mobile work tool select a brake pressure.

there it is preferred if the two working lines over each a Nachsaugleitung are connected to the tank, wherein in each Nachsaugleitung a in the direction of the working line opening check valve is arranged. This will cause cavitation during braking avoided, and it can with minimal resistance pressure medium of the rotary machine acting as a pump via the low-pressure side Be sucked work.

at a preferred embodiment of the invention Slew Drive is a proportional control spool valve 4/3-way valve, which is in a basic position of its valve body shuts off the pump line and the two working lines, and in switching positions of its valve body a working line with the pump line and the other working line with the tank combines.

The Pump can be a pressure-controlled or pressure-controlled variable pump be. Thus, in regenerative braking, the power of the Pump down regulated accordingly or be adjusted.

alternative The pump can also be a volume-controlled variable, thereby must be provided on the slewing motor, a speed sensor. By The speed sensor can be the amount of regenerative fed Pressure medium can be determined, and the variable displacement pump can accordingly down regulated or adjusted.

to Energy savings can be the delivery volume of the variable displacement pump electronically from the position of at least one set by the operator Actuator can be determined and adjusted.

Preferably the unloading valve is a proportional 2/2-way valve in the opening direction from the pressure in the pump line and in the closing direction of a spring is acted upon. Through this directional valve or pressure relief valve can be used during braking pressure medium that is not regenerative from which at least one other consumer can be used, from the pump line to the tank.

Out For optimal use of braking energy depending the absorption capacity of the at least one further consumer it is preferred if the unloading valve in addition in the closing direction from the pressure of a load-sensing signaling line charged with the inlet working line and with a Working line of the at least one further consumer of the mobile Working device is connected.

Because of The significant moments of inertia become mobile work tools preferred with a heavy or heavily loaded superstructure or superstructure, such as B. in an excavator or crane, the operable as a pump Slewing gear motor with the superstructure or superstructure of the excavator or crane is in active connection.

in the The following will be with reference to the figures, various embodiments the invention described in detail. Show it:

1 a first embodiment of a hydraulic slewing drive according to the invention with Druckschaltaltventilen; and

2 a pressure-adjusting valve of a second embodiment of a hydraulic slewing drive according to the invention.

1 shows a first embodiment of a hydraulic slewing drive according to the invention. He has a variable displacement pump 1 in an open circuit from a tank T pressure fluid into a pump line 2 promotes. About this pump line 2 becomes a slewing motor 4 and at least one other not shown consumer of a mobile implement (eg excavator) supplied with pressure medium.

The slewing motor 4 is over two working lines 6 . 8th to two working ports A, B of a continuously adjustable control valve 10 connected. The control way valve 10 is still on a pump port P to the pump line 2 and connected via a tank connection T to the tank T. In an in 1 shown center position of a valve body, not shown control directional control valve 10 All four ports A, B, P, T are blocked.

The slewing motor 4 is about a wave 12 with a (not shown) construction or superstructure of the mobile implement in operative connection.

According to the state of the art, a (mutually possible) rotation or pivoting of the superstructure or upper carriage takes place by means of a corresponding proportional adjustment of a valve body (not shown) of the control directional control valve 10 , In this case, in the direction of a shifted valve body, the connection A and thus the working line 6 supplied with high pressure, while the pressure medium on the low pressure side via the working line 8th and the work connection B flows back to tank T. When in direction b shifted valve body, a reverse rotational direction of the structure or superstructure is obtained in which the pressure medium high pressure side of the pump port P via the working port B and the working line 8th to the slewing motor 4 flows and from there over the work line 6 and the working port A back to the tank T.

The tank T is via a tank line 14 also connected to the low pressure side of at least one other consumer of the mobile implement.

To the (common) pump line 2 is an unloading valve 16 connected, which is designed as a proportional 2/2-way valve and the pump line 2 relieved when a maximum pressure to tank T is exceeded. For this purpose, a valve body of the unloading valve 16 from the in 1 shown basic position shifted in the direction indicated by a. It acts via a control line 18 in the opening direction, the pressure of the pump line 2 , while in the closing direction, a spring 20 and the pressure of a load sensing signaling line LS acts. In the load-sensing reporting line LS, the pressure of the highest-load currently actuated consumer of the mobile implement prevails. For comparison, the turning of the pressure of those working line 6 . 8th used for the determination of the load highest consumer, in the pressure medium to the slewing motor 4 flows. During braking operation of the slewing gear, this pressure is comparatively low.

According to the invention, the slew motor 4 also be operated as a pump and - depending on the direction of rotation - pressure medium in one of two regeneration lines 22a . 22b . 24a . 24b promote. This operating condition arises according to the invention when the driver or operator of the mobile implement the control valve 10 on the (in 1 shown) middle position, so as to end a rotational movement of the superstructure or superstructure. The rotational energy due to inertial forces drives over the shaft 12 the rotary machine acting as a pump 4 , whereby this through the appropriate regeneration line 22a . 22b or 24a . 24b and continue through a connecting line 26 Pressure medium in the pump line 12 promotes. Thus, the kinetic energy is converted to decelerate into hydraulic energy to supply the at least one other consumer of the mobile implement. This can in the case of the excavator described here z. B. be a hydraulic cylinder of his stem or his jib. In this case, the corresponding pressure medium flows in the pump line 2 in 1 to the left.

If no such consumer is operated in the period of regenerative braking, the pressure medium flows through the Unloadingventil 16 to tank T. In the load-sensing signaling line LS, the relatively low pressure of the working line prevails 6 . 8th , in the pressure medium from the slewing motor 4 is sucked. Including the one by the spring 20 applied pressure equivalent is in the closing direction of the unloading valve 16 acting pressure less than that through the control line 18 in the opening direction acting pressure, so that in this operating state, the unloading valve 16 opens.

If, in contrast, during the braking of the slewing another consumer is operated, the regenerative pressure fluid flow can flow to these consumers, the variable displacement 1 down can be regulated and so the energy consumption of the mobile implement can be lowered.

In every regeneration line 22a . 22b . 24a . 24b is a pressure switch valve 28 . 30 intended. This opens only at a certain spring by an opening pressure in the regeneration line 22a . 24a , wherein this opening pressure via a respective control or leakage oil line 36 . 38 in the opening direction of the corresponding pressure switching valve 28 . 30 acts.

Furthermore, at every working line 6 . 8th a suction line 40 . 42 connected via a common connection line 44 to the tank line 14 or the tank T are connected. In every suction line 40 . 42 is a check valve 46 . 48 arranged in the direction of the tank T and the connecting line 44 to the respective work management 6 . 8th opens as it closes in the opposite direction. This arrangement makes it possible for the slewing gear motor acting as a pump 4 especially in regenerative braking operation to avoid loss of cavitation loss of pressure medium from the tank T nachzusaugen.

In engine operation of the slewing motor 4 becomes the valve body (not shown) of the pilot valve 10 z. B. shifted into one of the switching positions marked with a, whereby pressure medium through the working line 6 to the slewing motor 4 flows and from the check valve 46 is prevented from flowing to the tank T.

The variable pump 1 can be pressure-controlled or pressure-controlled or alternatively quantity-controlled. In the latter case is at the shaft 12 a speed sensor 50 intended. In the regenerative braking mode, the volumetric flow rate is determined or calculated by means of this, that of the rotating-gear motor acting as a pump 4 into the pump line 2 is encouraged. Based on this value, the delivery volume of the variable displacement pump 1 reduced by swinging back.

2 shows one of two pressure switching valves 28 ' . 30 ' a second embodiment of the hydraulic slewing drive according to the invention. The pressure switching valves 28 ' . 30 ' replaces the pressure switching valves 28 . 30 out 1 , In addition, the second embodiment is similar to the first embodiment according to 1 ,

A bias of acting in the closing direction springs of the two pressure switching valves 28 ' . 30 ' is adjustable. This allows the opening pressure or brake pressure in the regeneration line 22a . 24a set by the driver or operator of the mobile implement.

The two pressure switching valves 28 ' . 30 ' can have two different bias voltages (such as pressure switch stages in pressure relief valves) or a continuously adjustable bias of their springs. This is achieved by a biasing or actuating piston, which can be acted upon by a control pressure P _ST , against which the springs are supported. The actuator piston can have different positions in the respective pressure switch valve 28 ' . 30 ' taking.

Disclosed is a hydraulic slewing drive for a mobile Work tool with a pump, which has a pump line is connected to a control-way valve, wherein the pump line via an unloading valve is relieved to a tank. Furthermore has the slewing drive two working lines, over which the Control-way valve is connected to a slewing motor, wherein at least one other consumer will be supplied by the pump can. According to the invention can be at a delay acting as a pump slewing motor over at least a pressure switch valve pressure medium fed into the pump line become.

LIST OF REFERENCE NUMBERS

1

variable

2

pump line

4

Slewing motor

6 8th

working line

10

Tax-way valve

12

wave

14

tank line

16

Unloadingventil

18

control line

20; 120

feather

22a, 22b

regeneration line

24a, 24b

regeneration line

26

connecting line

28 30; 28 ', 30'

Pressure sequence

32 34

feather

36 38

Drain line

40 42

subsequent suction

44

connecting line

46 48

check valve

50

Speed sensor

A, B

working port

P

pump connection

T

Tank connection / Tank

LS

Load-sensing message line

PST

control pressure

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

• - DE 19833489 A1 [0004]
• US 6584769 [0006]
• - DE 69735941 T2 [0007]

Claims (13)

Hydraulic slewing drive for a mobile implement with a pump ( 1 ) via a pump line ( 2 ) with a control directional control valve ( 10 ), the pump line ( 2 ) via an unloading valve ( 16 ) is relieved to a tank (T), and with two working lines ( 6 . 8th ) via which the control directional control valve ( 10 ) with a slewing motor ( 4 ), whereby from the pump ( 1 ), it is also possible to supply at least one further consumer, characterized in that, in the case of a deceleration of the rotary-machining motor acting as a pump ( 4 ) of this via at least one pressure switch valve ( 28 . 30 ; 28 ' . 30 ' ) Pressure medium into the pump line ( 2 ) can be fed. Hydraulic slewing drive according to claim 1, wherein each working line ( 6 . 8th ) one in the pump line ( 2 ) regeneration line ( 22a . 22b . 24a . 24b ), in each of which a pressure switch valve ( 28 . 30 ; 28 ' . 30 ' ) is provided. Hydraulic slewing drive according to claim 2 with two pressure switching valves ( 28 . 30 ; 28 ' . 30 ' ), wherein a Zuschaltdruck each Druckzuschaltventils ( 28 . 30 ; 28 ' . 30 ' ) higher than a maximum opening pressure of the unloading valve ( 16 ). Hydraulic slewing drive according to claim 3, wherein the two pressure switching valves ( 28 . 30 ; 28 ' . 30 ' ) in the opening direction of the pressure in the working line ( 6 . 8th ) and in the closing direction of a spring ( 32 . 34 ) are acted upon, and wherein a spring-side drain line ( 36 . 38 ) of each pressure switching valve ( 28 . 30 ; 28 ' . 30 ' ) is connected to the tank (T). Hydraulic slewing drive according to claim 4, wherein a bias of the spring ( 32 . 34 ) is adjustable via a controllable by a control pressure (P _ST ) actuating piston. Hydraulic slewing drive according to one of the claims 3 to 5, wherein the two working lines ( 6 . 8th ) via one each Nachsaugleitung ( 40 . 42 ) are connected to the tank (T), wherein in each Nachsaugleitung ( 40 . 42 ) in the direction of the working line ( 6 . 8th ) opening check valve ( 46 . 48 ) is arranged. Hydraulic slewing drive according to one of the preceding claims, wherein the control directional control valve, a proportional 4/3-way valve ( 10 ), in a basic position of its valve body, the pump line ( 2 ) and the two working lines ( 6 . 8th ) shuts off, and that in switching positions of its valve body a working line ( 6 . 8th ) with the pump line ( 2 ) and the other management ( 6 . 8th ) connects to the tank (T). hydraulic slewing drive according to one of the preceding Claims, wherein the pump is a pressure-controlled or pressure controlled variable pump is. Hydraulic slewing drive according to one of the claims 1 to 7, wherein the pump is a quantity-controlled variable displacement pump ( 1 ), and wherein at the rotary engine a speed sensor ( 50 ) is provided. hydraulic slewing drive according to the claims 8 or 9, wherein the delivery volume of the variable displacement pump electronically from the position of at least one operator-controlled actuator is adjustable. Hydraulic slewing drive according to one of the preceding claims, wherein the Unloadingventil a proportional 2/2-way valve ( 16 ) is in the opening direction of the pressure in the pump line ( 2 ) and in the closing direction of a spring ( 20 ) is acted upon. Hydraulic slewing drive according to claim 11, wherein the unloading valve ( 16 ) is acted upon in the closing direction by the pressure of a load sensing signaling line (LS), which with the inlet working line ( 6 . 8th ) and connected to a working line of the at least one further consumer of the mobile working device. Hydraulic slewing drive according to one of the preceding claims, wherein the mobile working device is an excavator or crane, and wherein the rotary drive motor operable as a pump ( 4 ) is in operative connection with a body or superstructure of the excavator or crane.

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