WO2011012187A1

WO2011012187A1 - Slewing gear drive

Info

Publication number: WO2011012187A1
Application number: PCT/EP2010/003572
Authority: WO
Inventors: Seppo Antero Tikkanen; Wolfgang Kauss; Edwin Heemserk; Uwe Neumann; Arne Weidemann
Original assignee: Robert Bosch Gmbh
Priority date: 2009-07-29
Filing date: 2010-06-15
Publication date: 2011-02-03
Also published as: DE102009035216A1

Abstract

A hydraulic slewing gear drive for a mobile working apparatus is disclosed, having a pump (1), which is connected via a pump line (2) to a control directional valve (10), wherein the pump line (2) can be relieved by means of an unloading valve (16) to a tank (T). The slewing gear drive furthermore has two control lines (6, 8), by means of which the control directional valve (10) is connected to a slewing gear motor (4), wherein the pump (1) can also supply at least one further load (1). According to the invention, upon the deceleration of the slewing gear motor (4) acting as a pump, a pressure medium can be fed into the pump line (2) by means of at least one pressure sequence valve (28, 28', 30, 30').

Description

Description slewing drive

The invention relates to a hydraulic slewing gear drive for mobile working equipment (for example excavator) according to the preamble of patent claim 1.

In hydraulic slewing drives a slewing motor to drive a superstructure or superstructure is supplied by a pump via a directional control valve with pressure medium.

Upon completion of the rotational movement via a control of the directional control valve, brake energy is generated as a function of the rotational speed and the mass of the rotated superstructure or superstructure. This is usually reduced by acting as a pump slewing motor and pressure relief valves, the pressure fluid flows back into a tank.

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.

A disadvantage of such rotary drives that the braking energy can not be regenerated. In particular, in mobile work equipment whose heavy structure is often rotated and slowed down, often results in this way considerable energy loss.

In the document US 6,584,769 a hydraulic circuit is disclosed, wherein pressure switching valves are arranged between each connection of the slewing gear 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.

A disadvantage of the latter hydraulic slewing drives is the device-technical complexity in particular in connection with the hydraulic accumulator and the associated valve technology.

In contrast, the invention is based on the object to provide a hydraulic slewing drive for mobile equipment that can be regeneratively braked with low device complexity.

This object is achieved by a hydraulic slewing drive according to claim 1.

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

The inventive hydraulic slewing drive for a mobile working device has a pump which is connected via a pump line to a control-way valve, wherein the pump line via a Unloadingventil is relieved to a tank. Furthermore, the slewing drive has two working lines, via which the control directional control valve is connected to a slewing motor, wherein at least one further consumer can be supplied by the pump. In this case, in a delay of the acting as a pump slewing motor of this via at least one Druckzuschaltventil pressure medium can be fed into the pump line. This is a regenerative braking of a superstructure or superstructure of the mobile implement possible, with other consumers of the mobile implement are additionally supplied with the appropriate pressure medium.

In a particularly preferred embodiment, a regeneration line which opens out into the pump line branches off from each working line, in each of which a pressure-adjusting valve is provided. This regenerative braking is possible in both directions of rotation of the slewing motor.

A preferred embodiment of the slewing drive according to the invention has two pressure switching valves, wherein a connection pressure of the pressure switching valves is higher than a maximum opening pressure of the unloading valve. As a result, at the moment of the opening of the respective pressure switching valve, the pressure in the pump line is lower than the pressure in the respective working line, so that an outflow of the pressure medium can take place, which is thus available to other consumers of the mobile working device.

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 leakage oil connection of each pressure switching valve is connected to the tank. Thus, an independent of the pressure in the pump line opening behavior of the pressure switching valves is guaranteed.

In a preferred embodiment, a bias of the spring via an actuatable by a control pressure adjusting piston is adjustable. This allows an operator or driver of the mobile work unit to select a brake pressure.

It is preferred if the two working lines are connected via a respective suction line with the tank, wherein in each Nachsaugleitung a in the direction of the working line opening check valve is arranged. In order for cavitation is avoided during braking, and it can be nachgesaugt with minimal resistance pressure medium from acting as a pump slewing motor via the low-pressure side working line. In a preferred embodiment of the slewing drive according to the invention, the control-way valve is a proportional 4/3-way valve which shuts off the pump line and the two working lines in a basic position of its valve body, and in switching positions of its valve body a working line with the pump line and the other working line with connects to the tank.

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

Alternatively, the pump may also be a quantity-controlled variable displacement pump, while a rotational speed sensor must be provided on the rotary engine. By the speed sensor, the amount of the regeneratively fed pressure medium can be determined, and the variable displacement can be regulated down or adjusted accordingly.

To save energy, the delivery volume of the variable displacement pump can be determined and adjusted electronically from the position of at least one operating device set by the operator.

Preferably, the unloading valve is a proportional 2/2-way valve which is acted upon in the opening direction by the pressure in the pump line and in the closing direction by a spring. By means of this directional valve or pressure limiting valve, pressure medium which can not be used regeneratively by the at least one further consumer can flow away from the pump line to the tank during braking.

For reasons of optimal use of the braking energy as a function of the absorption capacity of the at least one further consumer, it is preferred if the unloading valve is additionally acted upon in the closing direction by the pressure of a load-sensing signaling line which is connected to the inlet working line and to a working line of at least one other consumer of the mobile implement is connected.

Because of the significant moments of inertia mobile work equipment with a heavy or heavily loaded structure or superstructure are preferred, such. B. in an excavator or crane, wherein the operable as a pump slewing motor is in operative connection with the construction or superstructure of the excavator or crane.

In the following, various embodiments of the invention will be described in detail with reference to FIGS. Show it:

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

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

FIG. 1 shows a first exemplary embodiment of a hydraulic slewing gear drive according to the invention. He has a variable displacement pump 1, which promotes pressure medium in a pump line 2 in an open circuit from a tank. Via this pump line 2, a slewing gear motor 4 and at least one further consumer, not shown, of a mobile working device (eg excavator) are supplied with pressure medium.

The slewing gear motor 4 is connected via two working lines 6, 8 to two working ports A, B of a continuously adjustable control-way valve 10. The control valve 10 is further connected via a pump port P to the pump line 2 and a tank port T to the tank T. In a middle position of a non-illustrated valve body control directional control valve 10 shown in Figure 1, all four ports A, B, P, T are shut off.

The slewing motor 4 is connected via a shaft 12 with a (not shown) construction or superstructure of the mobile implement in operative connection. According to the prior art, there is a (double-sided possible) rotation or pivoting of the superstructure or superstructure by appropriate proportional adjustment of a valve body (not shown) of the control-directional valve 10. In the case of a valve body displaced in direction a, the connection A and thus the working line 6 supplied with high pressure, while the pressure medium flows back on the low pressure side via the working line 8 and the working port B to the tank T. When in the direction b shifted valve body, a reverse direction of rotation of the superstructure or superstructure is obtained in which the pressure medium hochd back flows from the pump port P via the working port B and the working line 8 to the rotor motor 4 and from there via the working line 6 and the working port A. to the tank T.

In this case, the tank T is connected via a tank line 14 with the low pressure side of at least one further consumer of the mobile implement.

To the (common) pump line 2, an unloading valve 16 is connected, which is designed as a proportional 2/2-way valve and the pump line 2 relieved when exceeding a maximum pressure to the tank T. For this purpose, a valve body of the unloading valve 16 is moved from the basic position shown in Figure 1 in the direction indicated by a. It acts via a control line 18 in

Opening direction of 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 pressure of those working line 6, 8 is used for the determination of the highest-load consumer, flows in the pressure medium to the rotating mechanism motor 4 from the slewing. During braking operation of the slewing gear, this pressure is comparatively low.

According to the invention, the slewing gear motor 4 can also be operated as a pump and thereby - depending on the direction of rotation - pressure medium in one of two regeneration lines 22a, 22b, 24a, 24b promote. This operating state is produced according to the invention when the driver or operator of the mobile working device switches the control directional control valve 10 to the middle position (shown in FIG. 1) so as to end a rotational movement of the superstructure or superstructure. Due to inertia forces existing rotational energy drives via the shaft 12 acting as a pump slewing motor 4, whereby this promotes through the corresponding regeneration line 22a, 22b or 24a, 24b and further through a connecting line 26 pressure medium in the pump line 12. 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 be in the case of the excavator described here, for example, a hydraulic cylinder of his stem or his jib. In this case, the corresponding pressure medium flows in the pump line 2 in Figure 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 the tank T. It prevails in the load-sensing reporting line LS, the relatively low pressure of the working line 6, 8, sucked in the pressure fluid from the slewing motor 4 becomes. Including the pressure equivalent applied by the spring 20, the pressure acting in the closing direction of the unloading valve 16 is lower than the pressure acting through the control line 18 in the opening direction, so that the unloading valve 16 opens in this operating state.

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

In each regeneration line 22a, 22b, 24a, 24b, a pressure switching valve 28, 30 is provided. This opens only at an opening pressure defined in the regeneration line 22a, 24a by a respective spring, this opening pressure acting via a respective control or leakage oil line 36, 38 in the opening direction of the corresponding pressure switching valve 28, 30.

Furthermore, a Nachsaugleitung 40, 42 is connected to each working line 6, 8, which are connected via a common connecting line 44 to the tank line 14 and the tank T. In each Nachsaugleitung 40, 42 a check valve 46, 48 is arranged, which in the direction of the tank T and the connecting line 44 to the respective working line 6, 8 opens, while it closes in the opposite direction. This arrangement makes it possible for the rotary-machining motor 4 acting as a pump, in particular during the regenerative braking operation, to draw in low-pressure pressure medium from the tank T in order to avoid cavitation.

In engine operation of the rotary engine 4, the valve body (not shown) of the pilot valve 10 is e.g. shifted to one of the switching positions indicated by a, whereby pressure fluid flows through the working line 6 to the rotating mechanism motor 4 and is prevented by the check valve 46 to flow to the tank T.

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

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

A bias of acting in the closing direction springs of the two pressure switching valves 28 ', 30' is adjustable. As a result, the opening pressure or brake pressure in the regeneration line 22a, 24a can be adjusted 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 boost stages in pressure relief valves) or a continuously adjustable bias of their springs. This is achieved by a biased by a control pressure PST biasing or actuator piston, where the Feathers supported. The adjusting piston can assume different positions in the respective pressure-adjusting valve 28 ', 30'.

Disclosed is a hydraulic slewing drive for a mobile working device with a pump which is connected via a pump line to a control-way valve, wherein the pump line is relieved via an unloading valve to a tank. Furthermore, the slewing drive has two working lines, via which the control directional valve is connected to a slewing motor, wherein at least one further consumer can be supplied by the pump. According to the invention, pressure medium can be fed into the pump line by means of a delay of the rotating-mechanism motor acting as a pump via at least one pressure-adjusting valve.

Claims

claims

1. hydraulic slewing drive for a mobile implement with a pump (1) which is connected via a pump line (2) with a control-way valve (10), wherein the pump line (2) via an Unloadingventil (16) to a tank (T ) is relieved, and with two working lines (6, 8) via which the control-way valve (10) is connected to a slewing motor (4), wherein at least one further consumer can be supplied by the pump (1), characterized in that pressure medium can be fed into the pump line (2) during a deceleration of the rotating-mechanism motor (4) acting as a pump by the latter via at least one pressure-adjusting valve (28, 30; 28 ', 30').

2. hydraulic slewing drive according to claim 1, wherein from each working line (6, 8) in the pump line (2) opening branching regeneration line (22a, 22b, 24a, 24b), in each of which a pressure-adjusting valve (28, 30, 28 ', 30 ') is provided.

3. hydraulic slewing drive according to claim 2 with two pressure switching valves (28, 30, 28 ', 30'), wherein a connection pressure of each pressure switching valve (28, 30, 28 ', 30') higher than a maximum opening pressure of the unloading valve (16) is.

4. hydraulic slewing drive according to claim 3, wherein the two

Druckzuschaltventile (28, 30, 28 ', 30') in the opening direction of the pressure in the working line (6, 8) 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).

5th hydraulic slewing drive after. Claim 4, wherein a bias of the spring (32, 34) via one of a control pressure (P _S τ) acted upon adjusting piston is adjustable.

6. hydraulic slewing drive according to one of the claims 3 to 5, wherein the two working lines (6, 8) via a respective Nachsaugleitung (40, 42) to the tank (T) are connected, wherein in each Nachsaugleitung (40, 42) an in Direction to the working line (6, 8) opening check valve (46, 48) is arranged.

7. hydraulic slewing drive according to one of the preceding claims, wherein the control-way valve is a proportional 4/3-way valve (10), the pump line (2) and the two working lines (6, 8) shuts off in a basic position of its valve body, and in switching positions of its valve body, a working line (6, 8) with the pump line (2) and the other working line (6, 8) with the tank (T) connects.

8. hydraulic slewing drive according to one of the preceding claims, wherein the pump is a pressure-controlled or pressure-controlled variable displacement pump.

9. 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 on the rotary engine, a speed sensor (50) is provided.

10. hydraulic slewing drive according to the patent claims 8 or 9, wherein the delivery volume of the variable displacement electronically from the position of at least one operator set by the operator is adjustable.

11. hydraulic slewing drive according to one of the preceding claims, wherein the unloading valve is a proportional 2/2-way valve (16) which is acted upon in the opening direction by the pressure in the pump line (2) and in the closing direction of a spring (20).

12. 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), with the inlet working line (6, 8) and with a working line of the at least one further consumer of the mobile working device is connected.

13. hydraulic slewing drive according to one of the preceding claims, wherein the mobile implement is an excavator or crane, and wherein the operable as a pump slewing motor (4) is in operative connection with a structure or superstructure of the excavator or crane.