EP1440211A1

EP1440211A1 - Machine tool and method for operating a machine tool

Info

Publication number: EP1440211A1
Application number: EP02802301A
Authority: EP
Inventors: Jürgen LEGNER; Wolfgang Rebholz; Hermann Beck
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2001-10-30
Filing date: 2002-10-24
Publication date: 2004-07-28
Anticipated expiration: 2022-10-24
Also published as: KR20050039716A; WO2003038200A1; EP1440211B1; JP2005507471A; DE10153458A1; US20040249537A1; DE50202947D1; CN1276156C; CN1556888A

Abstract

The invention concerns a machine tool equipped with a hydrostatic drive, a chassis wherein is housed a motor for driving the wheels and an upper structure mounted pivoting on the chassis and comprising a pump for supplying driving pressure. Between the chassis and the upper structure there is provided a rotating passage and in the chassis are housed one or several electronic components constituting a chassis electronic system for controlling and/or regulating elements of the chassis.

Description

Working machine and method for operating a working machine

The present invention relates to a work machine with a hydrostatic drive, in particular a mobile excavator according to the preamble of claim 1 and a method for operating the work machine.

Such machines are used in many ways, e.g. as a mobile excavator, crane, etc. According to the state of the art, they have a hydrostatic travel drive and have an undercarriage and an uppercarriage rotatably arranged on the undercarriage; A drive motor for driving the wheels is provided in the undercarriage and is supplied with pressure medium by a pump arranged in the superstructure, it being possible for further high-pressure consumers to be provided.

According to the prior art, no electrical energy or electrical components are generally provided in the undercarriage in mobile excavators. The necessary for operation. High pressure and control pressure hydraulics are routed from the upper to the undercarriage through a rotating union. There are at least two high-pressure consumers in the undercarriage (hydraulic motor for the travel drive and dozer blade or support). In addition, the pressure supply for the mostly double-circuit hydraulic power brake and for the steering must also be routed from the upper to the undercarriage. Furthermore, control signal lines for the transmission and hydraulic motor creeper gearshift as well as the swing axle lock are required, which also lead through the rotating union become. This results in a complex and expensive tubing for the above functions.

DE 19956402 AI discloses a mobile excavator in which the control valve required to control the direction of movement and speed of the vehicle is arranged in the region of the uriter wagon. This reduces the number of hydraulic connections for the drive to two lines, namely a delivery line and a tank line. Nevertheless, the number of additional lines to be routed through the rotating union remains high.

Electrical equipment is often used in the undercarriage of material handling machines or industrial equipment. The number of additional control and monitoring signals can no longer be carried out hydraulically in these devices, so that in this case digital or electrical control and monitoring signals are transmitted from the superstructure to the undercarriage through the rotating union. According to the state of the art, no electronic components are provided in the undercarriage.

Nowadays, a high-pressure, continuously variable axial piston hydraulic motor with a built-in brake valve and secondary pressure relief valves is normally used for the travel drive as standard. The engine is on a small swallowing volume (qmin) until a high pressure is reached. At constant high pressure, the motor is adjusted from the small (qMin) to the large (qMax) displacement, which increases the torque. The integrated, high-pressure-dependent controller is only controlled by the high-pressure inlet during train operation. In the brake in turn, the motor is on a small swallowing volume (qmin).

Due to this control system, the hydraulic braking torque is limited to small values. As a rule, a device with such a control concept brakes with a maximum deceleration of approx. 10 - 12%. This means that there may be situations where the braking power is insufficient to ensure safe operation. This can be the case when driving

Overrun may be the case if the gradient is steeper than the braking capacity of the hydraulic motor, which creates the risk of overturning for the entire drive train.

This cannot be avoided by the driver releasing the accelerator pedal; the device is not braked, but accelerated. In addition, when the accelerator pedal is not actuated, no high-pressure oil is pumped from the pump to the hydraulic motor. The oil delivered to qMin by the hydraulic motor cannot flow out through the brake valve to the tank, but sprays out on the secondary valves to the low pressure side. The very small oil volume in the hydraulic motor is heated up very quickly and can therefore destroy the hydraulic motor and in some cases the attached gear.

The present invention is based on the object of specifying a work machine, in particular a mobile excavator, which avoids the disadvantages of the prior art. In particular, the number of lines between the uppercarriage and the undercarriage should be reduced and safety and driving comfort should be improved. In addition, it should be possible to diagnose the components used to perform what is not possible according to the current state of the art.

Furthermore, the functionality of the working machine should be expandable without a great deal of construction work, while at the same time reducing the production costs.

Furthermore, a method for operating the machine is to be presented.

This object is achieved for a work machine by the features of the characterizing part of patent claim 1. The method is the subject of claim 26. Further developments emerge from the subclaims.

Accordingly, it is proposed to use one or more electronic components in the undercarriage which serve to control and / or regulate the undercarriage components.

Advantageously, the undercarriage electronics used according to the invention are connected to the on-board electronics in the superstructure by means of a rotary feedthrough via a communication link (for example CAN or DC bus). The supply voltage for the undercarriage electronics also comes from the rotating union.

The proposed use of electronic components in the undercarriage means that a large number of hydraulic connections between the superstructure and undercarriage can be dispensed with. The components in the undercarriage are directly controlled and monitored electrically and / or hydraulically. This also enables diagnosis of the components in the undercarriage, because Any actuators and sensors can be diagnosed by the undercarriage electronics.

In addition, an expanded range of functions can be realized by the construction according to the invention, as will be described in detail below.

The invention is explained in more detail below with reference to the drawing. I

In this represent:

Figure 1: A block diagram of a mobile excavator according to the prior art;

Figure 2: A block diagram of a mobile excavator according to a first embodiment of the invention; and

Figure 3: A block diagram of a mobile excavator according to another embodiment of the invention.

In all figures, the separation between the uppercarriage and the undercarriage is illustrated by the dashed line.

In the superstructure of a work machine according to the prior art according to FIG. 1, up to 4 pumps are attached to the internal combustion engine. In addition to the main working pump 1, there are a pilot pump 2, a brake pump 3 and a steering pump 4.

The main working pump 1 supplies all high-pressure consumers (cylinders, hydraulic motors) in an open hydraulic raulikkreislauf. All high-pressure consumers in the undercarriage, such as the hydraulic motor, dozer blade, support, must be supplied by the rotating union. In some cases today the swivel function is operated with another pump in a closed circuit.

The pilot pump 2 pumps the oil for the entire hydraulic pilot control. The pilot control valves have a direct influence on the various main control valves both in the uppercarriage (boom, stick, bucket, slewing gear, ...) and in the undercarriage (traction motor, dozer blade, support, etc.). The hydraulic control functions in the undercarriage for gear shifting, hydraulic motor changeover (creeper gear), swing axle lock etc. are routed individually through the rotating union.

In the brake compact block 5, bladder accumulators are filled with an accumulator charging unit, which allow a prescribed emergency operation in the event of a failure of the pressure supply. The brake compact block 5 is arranged in the superstructure in such a way that the two brake circuits of this block are controlled hydraulically by the rotary leadthrough.

The hydraulic steering unit 6 is arranged directly on the steering wheel 7 in the cabin and is supported by the steering pump 4

Oil is supplied, with two lines leading from the hydraulic steering unit 6 via the rotary union to the double-acting steering cylinder.

According to the prior art, a hydraulic downshift lock is provided on the transmission 8, which prevents downshifting and thus overturning of the hydraulic motor at high driving speed. FIG. 2 shows a block diagram of a mobile excavator according to the invention.

Accordingly, all - except one - control lines between the uppercarriage and undercarriage are eliminated. According to the invention, the control signals for the gear shift, accelerator pedal, hydraulic motor and pendulum axle lock are sent to the superstructure electronics by electrical switch signals (analog and digital); from there the control signals reach the undercarriage electronics 10 via a communication link 9. The solenoid valves can thus advantageously be accommodated in the undercarriage; they are controlled by means of the undercarriage electronics 10.

It is intended to arrange the transmission control block 11 directly on the transmission 8 or in another suitable place in the undercarriage. It is particularly advantageous to implement an additional “front axle shutdown” function via a solenoid valve provided in the transmission control block, which can be electrically controlled by the undercarriage electronics.

The input and / or output speed on the transmission is measured by a speed sensor 12, this signal being processed by the undercarriage electronics 10, so that the downshift lock is effected electronically by means of this speed information.

In a variant of the invention, an automatic gear shift is provided. For this purpose, the signals from the speed sensor and the absorption volume are Position, ie the valve flow to the hydraulic motor proportional valve, evaluated by the undercarriage electronics 10.

The number of connections between the uppercarriage and the undercarriage is significantly reduced compared to the prior art, with additional functions in the undercarriage, such as. B. the described front axle shutdown are possible without additional connections between the superstructure and undercarriage.

By using the undercarriage electronics according to the invention, the functions in the undercarriage are logically linked. This results in a significant reduction in effort and an increase in safety during operation. For example, on a mobile excavator with a long boom and four-point support, the supports must be extended and locked before the boom can be used.

In the context of a further embodiment, it is proposed to use an electrically proportional adjustable hydraulic motor with superimposed pressure control instead of the high-pressure-dependent adjustable hydraulic motor used today, the proportional valve of which can be controlled by the undercarriage electronics 10. The engine has a brake valve, with secondary pressure relief valves being provided between the engine and the brake valve. When starting, this engine is at maximum swallowing volume and consequently torque and thus allows the machine to accelerate better from a standing start. The adjustment of the engine to a smaller swallowing volume can therefore be controlled depending on the accelerator pedal position and the drive speed of the transmission. For this purpose, an analog sensor is provided on the accelerator pedal. The accelerator pedal tion can also be detected by means of a pressure sensor between "accelerator pedal" and "slide".

This concept also has the advantage that the motor can be specifically adjusted to a larger swallowing volume during braking, which prevents overturning when driving downhill. If the accelerator pedal is released when driving downhill, the braking torque rises steadily over a specified time due to the adjustment of the hydraulic motor to a larger swallowing volume and the machine comes to a standstill. Overturning can thus almost be ruled out. When driving downhill, the driver is forced to press the accelerator pedal to be able to drive. The oil conveyed from the hydraulic motor to the tank is cooled so that overheating of the units in the undercarriage is largely avoided.

A particularly advantageous variant of the invention, which is the subject of FIG. 3, also provides for the hydraulic connections between the superstructure and undercarriage to be reduced to one connection. The number of line connections between the uppercarriage and the undercarriage is therefore limited to three, namely a hydraulic, an electrical and a communication connection. As a result, the entire undercarriage is designed as a closed system.

The number of oil pumps in the superstructure is accordingly reduced from four to one main working pump __ '. All control commands go in the form of electrical digital or analog signals to the on-board electronics in the uppercarriage and from there via the communication link to the undercarriage electronics 10, which forwards the control signals to the actuators. Furthermore, important status and diagnostic data from the actuators and sensors from the undercarriage diagnosed in the undercarriage electronics 10 and reported via the communication link 9 to the on-board electronics in the superstructure ("fault management"), emergency driving or emergency operating programs being able to be executed after the evaluation.

In order to implement a load-sensing control (high-pressure independent demand flow control) of the main work pump 1 'arranged in the superstructure, the pressure of the consumer with the highest load is reported from the undercarriage to the superstructure. In addition, when the power limit is reached, the oil flow in the superstructure to all working consumers is reduced uniformly, the oil flow to the consumers in the undercarriage being determined by the undercarriage electronics 10. This is particularly important in the event that several consumers are required at the same time during work (e.g. hydraulic motor, dozer blade, etc.).

In order to identify the consumer with the highest load, it is proposed within the scope of the present invention to transmit appropriate signals via the undercarriage electronics 10 to the supercarrier electronics, which are used for pump control, by means of pressure sensors in the lines carrying the load pressure. This construction has the advantage that no additional connection between the upper and lower carriage is required.

Another variant for the detection of the consumer with the highest load provides for the use of connected check valves which lead the load pressure of the consumer with the highest load to the superstructure via a hydraulic signaling line.

In contrast to the first variant, an additional hydraulic connection between the uppercarriage and undercarriage is required. The hydraulic power for the brakes, steering, hydraulic motor and dozer blade is diverted from the central pressure oil supply of the undercarriage. The control oil is preferably branched off by a control oil unit from the high-pressure supply of the undercarriage by means of a pressure reduction. The control of all consumers in the undercarriage is thus carried out by the undercarriage electronics 10.

The X-by Wire implementation is particularly advantageous

Systems, i.e. electronic systems that work completely without a mechanical fallback level, for steering and braking (steer-by-wire, brake-by-wire) in order to increase active safety.

For this purpose, according to the invention, a proportional electro-hydraulic steer-by-wire unit 13 and a brake-by-wire unit 14 are accommodated in the undercarriage, the corresponding electronic control being integrated in the undercarriage electronics 10 or in separate ones Components is housed.

The steer-by-wire component works as follows: The steering wheel movements in the steer-by-wire unit in the uppercarriage are converted into electrical signals and routed to the uppercarriage electronics. From there, this information reaches the undercarriage electronics 10 via the communication link 9, which in turn then controls the hydraulic steer-by-wire unit 13 electrically. In the steer-by-wire unit, the electrical signals are converted into hydraulic signals and passed on to the steering cylinder. Hydraulic accumulators for emergency operation are provided in the steer-by-wire unit 13 in the undercarriage. The steer-by-wire unit 13 can be mounted directly on the axle or in a suitable place in the undercarriage.

An advantageous further development of the invention provides that in the steer-by-wire unit in the uppercarriage an electric motor is used to simulate steering forces on the steering wheel in order to improve the driving experience.

Such a steering device would make it possible to fold it out of the driver's field of vision when driving on the construction site and to operate the steering using additional joysticks. This would significantly improve visibility when working and contribute to increased safety. In this context, it is proposed to implement a reset behavior when the steering wheel is released when cornering in the steering device. Another advantage of the steer-by-wire system is that disruptive hydraulic noises are eliminated from the driver's cab.

To implement the brake-by-wire system, sensors are provided that detect the brake pedal movements and convert them into electrical signals that are forwarded to the superstructure electronics. This information then passes via the communication link to the undercarriage electronics, which electrically controls the hydraulic brake-by-wire unit 14, the electrical signals being converted into hydraulic signals in the brake-by-wire unit and passed on to brake cylinders. In the brake-by-wire 14 unit in the undercarriage, hydraulic accumulators are also provided for emergency operation. As part of an advantageous development, wheel speed sensors are provided in order to be able to implement functions such as ABS, ASR, etc.

Reference sign

1.1 'main working pump

2 pilot pump

3 brake pump

4 steering pump

5 compact brake block

6 steering unit

7 steering wheel

8 gears

9 Communication connection

10 undercarriage electronics

11 transmission control block

12 speed sensor

13 Steer-by-wire unit

14 Brake-by-wire unit

Claims

Patent claims

1. Working machine with a hydrostatic drive, in particular a mobile excavator, with an undercarriage in which a drive motor is provided for driving the wheels and an upper carriage rotatably arranged on the undercarriage, which comprises a pump for supplying the travel drive with pressure medium, between upper - And undercarriage a rotary feedthrough is arranged, characterized in that one or more electronic components are provided as undercarriage electronics (10) in the undercarriage, which serve to control and / or regulate the undercarriage components.

2. Working machine according to claim 1, characterized in that the undercarriage electronics (10) is connected via a communication link (9) to the on-board electronics in the superstructure by means of the rotary feedthrough, the supply voltage for the undercarriage electronics (10) taking place via the rotary feedthrough.

3. Working machine according to claim 1 or 2, characterized in that a control line is provided between the upper and lower carriage.

4. Working machine according to one of the preceding claims, characterized in that the components, in particular sensors and actuators in the undercarriage of the undercarriage electronics (10) can be controlled and diagnosed electrically and / or hydraulically directly.

5. Working machine according to one of the preceding claims, characterized in that the transmission control block (11) is arranged directly on the transmission (8) in the undercarriage.

6. Working machine according to one of the preceding claims, characterized in that a "front axle shutdown" function is provided via a solenoid valve provided in the transmission control block (11), which is electrically controllable by the undercarriage electronics (10).

7. Working machine according to one of the preceding claims, characterized in that a downshift lock is provided which can be controlled electronically by the undercarriage electronics (10), the input and / or output speed being measurable by a provided speed sensor (12) and by the Undercarriage electronics (10) can be evaluated.

8. Working machine according to one of the preceding claims, characterized in that an automatic gear shift is provided, which can be controlled by the undercarriage electronics (10) on the basis of signals from the speed sensor and the swallowing volume setting.

9. Working machine according to one of the preceding claims, characterized in that the functions in the undercarriage are logically linked via the undercarriage electronics (10).

10. Working machine according to one of the preceding claims, characterized in that an electrically proportionally adjustable hydraulic motor with superimposed pressure Regulation is provided, the proportional valve of which can be controlled by the undercarriage electronics (10), the motor having a brake valve and secondary pressure relief valves between the motor and the brake valve.

11. Working machine according to claim 10, characterized in that the adjustment of the motor to a smaller swallowing volume is controllable depending on the accelerator pedal position and the input and / or output speed of the transmission.

12. Working machine according to claim 11, characterized in that an analog sensor is provided on the accelerator pedal. Or as in the 1st version by a control pressure sensor between accelerator pedal and "slide"

13. Working machine according to one of the preceding claims, characterized in that the hydraulic connections between the uppercarriage and the undercarriage are reduced to one connection, as a result of which the number of line connections between the uppercarriage and undercarriage is reduced to three, namely a hydraulic, an electrical and an Communication connection (9) is limited.

14. Working machine according to claim 13, characterized in that only one main working pump 1 'is arranged in the superstructure.

15. Working machine according to claim 14, characterized in that the main working pump __ 'has a high-pressure independent demand flow control.

16. Working machine according to claim 15, characterized in that pressure sensors are provided in the lines carrying the load pressure, the signals of which can be transmitted via the undercarriage electronics (10) to the superstructure electronics for the purpose of the main pump control.

17. Working machine according to one of the preceding claims, characterized in that steer-by-wire or brake-by-wire systems are provided for steering and / or brake.

18. Working machine according to claim 17, characterized in that a proportional electro-hydraulic steer-by-wire unit (13) and / or a brake-by-wire unit (14) is arranged in the undercarriage.

19. Working machine according to claim 18, characterized in that electronic control of the steer-by-wire unit (13) and the brake-by-wire unit (14) is integrated in the undercarriage electronics (10) or is accommodated in separate components.

20. Working machine according to claim 17, 18 or 19, characterized in that by means of the steer-by-wire unit in the superstructure, steering forces on the steering wheel (7) can be simulated by a provided electric motor.

21. Working machine according to one of the preceding claims, characterized in that the steering can optionally be operated by means of joysticks.

22. Working machine according to one of claims 17 to 19, characterized in that sensors are provided, which detect the brake pedal movements and convert them into electrical signals which can be forwarded to the undercarriage electronics (10) for controlling the brake-by-wire unit (14).

23. Working machine according to one of claims 17 to 22, characterized in that hydraulic accumulators for emergency operation are provided in the brake-by-wire unit (14) in the undercarriage.

24. Working machine according to one of the preceding claims, characterized in that wheel speed sensors are provided for the implementation of ABS or ASR systems.

25. Working machine according to one of the preceding claims, characterized in that the hydraulic power for the brake, steering, hydraulic motor and other consumers is branched off from the central pressure oil supply of the undercarriage, the control of all consumers in the undercarriage by the undercarriage electronics

(10) is done.

26. Method for operating a working machine with a hydrostatic drive, in particular a mobile excavator, with an undercarriage in which a drive motor is provided for driving the wheels and an upper carriage rotatably arranged on the undercarriage, which has a pump for supplying the drive with pressure medium comprises, a rotary feedthrough being arranged between the uppercarriage and undercarriage, in particular according to one of claims 1 to 25, characterized in that one or more electronic components as undercarriage electronics (10) are inserted in the undercarriage be set that serve to control and / or regulate the undercarriage components.

27. The method according to claim 26, characterized in that the sensors and actuators in the undercarriage are directly controlled and diagnosed electrically and / or hydraulically by the undercarriage electronics.

28. The method according to claim 26 or 27, characterized in that the functions in the undercarriage via the

Undercarriage electronics (10) can be logically linked.

29. The method according to any one of claims 26-28, characterized in that the hydraulic power for the brake, steering, hydraulic motor and other consumers is branched off from the central pressure oil supply of the undercarriage, all consumers in the undercarriage are controlled by the undercarriage electronics (10).

30. The method according to any one of claims 26-29, characterized in that the main working pump (1, 1 ') has a high-pressure independent demand flow control, the pressure of the highest load consumer being reported from the undercarriage to the uppercarriage and when the performance limit is reached Oil flow to the consumers is reduced uniformly and the oil flow to the consumers in the undercarriage is determined by the undercarriage electronics (10).

31. The method according to claim 30, characterized in that for the detection of the highest load consumer of sensors provided in the lines carrying the load pressure via the undercarriage electronics (10) ^~~ to the superstructure electrical nik be transmitted.

32. The method according to any one of claims 26 - 31, characterized in that the motor is controlled depending on the accelerator pedal position and the input and / or output speed of the transmission (8).

33. The method according to any one of claims 26 - 32, characterized in that the steering is optionally carried out via joysticks.