Patent Application
20200263379
Applicant claims priority under 35 U.S.C. § 119 of European Application No. 19157538.0 filed Feb. 15, 2019, the disclosure of which is incorporated by reference.
The invention relates to an underground construction device for introduction of pile-driven material into the ground. The invention furthermore relates to a method for operation of such an underground construction device.
In construction, underground construction devices are operated for underground construction work in a hydraulic group with different work devices having a hydraulic drive. The hydraulic group regularly consists of a hydraulic pump that is driven by an internal combustion engine, in particular by a supercharged diesel engine, of a work device having a hydraulic drive, in particular a hydraulic motor, as well as of a control or regulation unit. The hydraulic group is operated with a fluid in a hydraulic circuit. The product of the pressure stream and volume stream of the fluid yields the hydraulic power. In order to be able to make the power available that is required for the work device, the internal combustion engine that drives the hydraulic pump is dimensioned to be correspondingly large.
Possible work devices that are used are, in particular, vibrating pile-drivers or vibrators. These devices are used to introduce objects such as steel profiles, for example, into the ground or to pull them out of the ground or also to compact ground material. The ground is excited by means of vibration and thereby reaches what is called a “pseudo-liquid” state. The material to be pile-driven can then be pressed into the construction ground by means of a static top load. Vibrating pile-drivers generally have vibration exciters that act in linear manner, the centrifugal force of which is generated by means of rotating imbalances. The progression of the speed of the linear vibration exciter corresponds to a periodically recurring function, for example a sine function. The vibration exciters are driven using hydraulic rotary drives, which put the shafts on which the imbalances are arranged into rotation. To hold an object to be introduced into the ground, vibrating pile-drivers have a clamping pincer by way of which the vibrations of the vibrator as well as the static top load are transferred to the object being held.
In the case of construction sites that require a vibration-free method, for example near protected historical buildings or near hospitals, hydraulic presses are used as work devices. Such hydro-presses have an arrangement of clamping pincers that are each connected with a hydraulic cylinder and serve to hold an object, in each instance, for example a sheet pile. By activating the hydraulic cylinders, the objects held by the clamping pincers can be pressed into the ground or pulled out of it.
The clamping pincers arranged for holding the objects to be introduced into the ground or to be pulled out of the ground can be activated by means of multiple hydraulic clamping cylinders that are also driven by way of the fluid of the hydraulic group. The clamping pincer has great importance for safety technology. In order to guarantee secure fixation of an object to be introduced into the ground on the work device, a continuous pressure supply to the at least one clamping cylinder of the clamping pincer must be guaranteed so as to ensure the required clamping force. For this reason, in practice, the internal combustion engine continues to be operated during work breaks of the underground construction device, so as to maintain the comparatively low pressure required for the clamping force of the clamping pincers, and this continued operation results in a significant consumption of diesel fuel. To reduce this significant diesel consumption, it is proposed in DE 10 2013 103 715 A1 to recognize breaks in operation on the basis of operating parameters of the work device, and to automatically shut off the internal combustion engine during a break in operation. To ensure the static pressure required for the clamping force of the clamping pincer, applied to the clamping cylinder, this cylinder is supposed to be monitored, and if the pressure drops below a predetermined value, the internal combustion engine is supposed to be automatically turned on. In this regard, the diesel engine is supposed to be shut off only when the clamping pincer is open, in other words is not operating, or if the operation of the clamping pincer is ensured by way of control of the clamping pressure. If the clamping pressure drops as the result of a leakage of the clamping cylinder, the diesel engine is started up and more oil is supplied to the clamping cylinder.
A disadvantage of this proposed solution is that starting and subsequent operation of the internal combustion ending for restoring the pressure required for the clamping force requires a disproportionate amount of energy, i.e. diesel fuel. In order to feed in an additional few milliliters of hydraulic oil, a diesel engine having a coupling power of several hundred kilowatts is started up. More energy is required simply for starting the diesel engine than for feeding in more hydraulic oil. Furthermore, the diesel engine has an idle consumption that is in a very disadvantageous ratio to the power required to feed in additional hydraulic oil. In addition, the diesel engine is burdened by the power loss caused by the large hydraulic pumps connected with it, which are dimensioned for drive of the work device and generally rotate along with the diesel engine.
The invention wishes to provide a remedy for these disadvantages. The invention is based on the task of making available an underground construction device for which the energy consumption or diesel consumption of the underground construction device is reduced, in particular during breaks in operation. According to the invention, this task is accomplished by means of an underground construction device having a further hydraulic pump for building up the clamping pressure of the clamping cylinder of the clamping apparatus, which pump is operated by an electric motor.
With the invention, an underground construction device is made available, for which the energy consumption or diesel consumption of the underground construction device is reduced, in particular during breaks in operation. Because a further hydraulic pump is provided to build up the clamping pressure of the clamping cylinder of the clamping apparatus, which pump is operated by an electric motor, equalization of drops in pressure, for example due to a leakage of the clamping cylinder, is made possible without starting up the internal combustion engine. The electric motor for operation of the further hydraulic pump can be supplied by way of the rechargeable battery of the internal combustion engine, which is generally present for the required electric starter of the internal combustion engine.
In a further development of the invention, the hydraulic pump driven by the electric motor to build up the clamping pressure is a radial piston pump. As a result, providing the high pressure required for the clamping cylinder is made possible.
In an embodiment of the invention, the hydraulic pump driven by the electric motor to build up the clamping pressure is connected parallel to a hydraulic pump driven by the internal combustion engine to build up the clamping pressure. As a result, a redundant arrangement is achieved, in which the clamping cylinder can be supplied exclusively, in other words even during operation of the work device, by the hydraulic pump operated by the electric motor. Furthermore, maintaining the required clamping pressure is guaranteed using the hydraulic pump driven by the electric motor, even in the event of a failure of the internal combustion engine or of the hydraulic pump driven by it.
In a further embodiment of the invention, a pressure intensifier for increasing the hydraulic pressure made available by the electrically driven hydraulic pump is arranged behind this pump in the flow direction of the hydraulic fluid. As a result, the use of a hydraulic pump having smaller dimensions is made possible.
In a further development of the invention, the electrically driven hydraulic pump is controlled so that a higher pressure is made available—alone or in connection with a pressure intensifier—than the hydraulic pump operated by means of the internal combustion engine for building up the clamping pressure, wherein the maximal clamping pressure is preferably made available only by means of the electrically driven hydraulic pump. As a result, smaller dimensioning of the unit composed of electric motor and hydraulic pump for building up the clamping pressure is made possible.
In an embodiment of the invention, the internal combustion engine and the work device are connected with a controller that is set up for querying at least one operating state value in the event of a deactivated work device, so as to automatically stop the internal combustion engine or to recommend to the operator that the internal combustion engine be stopped, by way of a signal, in particular by way of a display message, if at least one operating state corresponds to an assigned default value. In this regard, it is advantageous if a temperature sensor for measuring the hydraulic fluid temperature or a temperature sensor for measuring the internal combustion engine oil temperature or both are provided, which temperature sensor is connected with the controller, wherein the controller is set up in such a manner that if a limit temperature assigned to a temperature sensor is not reached, stopping of the internal combustion engine or a recommendation for stopping the internal combustion engine does not occur.
In a further embodiment of the invention, a pressure sensor for continuous measurement of the clamping pressure of the clamping apparatus is provided, which sensor is connected with control and regulation equipment that is set up in such a manner that if the clamping pressure drops below a predetermined minimum pressure value, a pressure increase to a predetermined reference pressure value takes place by means of the pump operated by the electric motor. As a result, autarchic pressure regulation by way of the hydraulic pump operated by the electric motor is made possible, without startup of the internal combustion engine being required.
In a further development of the invention, the electric motor is supplied by way of a rechargeable battery, which is connected with a charging apparatus operated by means of the internal combustion engine, wherein a sensor is provided for continuous measurement of the charging state of the rechargeable battery, which sensor is connected with a control device for turning on the internal combustion engine, which device is set up in such a manner that if the charging state of the rechargeable battery drops below a predetermined minimal charging state, automatic startup of the internal combustion engine takes place. As a result, reliable operation of the electric motor for drive of the hydraulic pump operated by it is guaranteed.
The invention is furthermore based on the task of creating a method for operation of such an underground construction device, which method makes possible a reduction in the required energy demand or diesel demand of the carrier device. According to the invention, this task is accomplished by a method wherein the clamping pressure of the clamping cylinder of the clamping apparatus is maintained by a hydraulic pump that is operated by an electric motor, at least when the internal combustion engine is stopped. Because the clamping pressure of the clamping cylinder of the clamping apparatus is maintained, at least when the internal combustion engine is stopped, by means of a hydraulic pump that is operated by an electric motor, starting the internal combustion engine up in the event of a pressure drop of the clamping cylinder of the clamping apparatus is not necessary. It should be noted at this point that in comparison with the energy required to start up the internal combustion engine, the energy demand for additional feed to the clamping cylinder is less by about two powers of ten.
In a further development of the invention, the opening state of the clamping apparatus is queried as an operating state value, wherein the internal combustion engine is stopped only if the collet is closed and only in the event that the pump operated by way of the electric motor is activated. As a result, unintentional opening of the collet is effectively counteracted.
In an embodiment of the invention, the electric motor is operated by way of a rechargeable battery, and the charging state of the rechargeable battery is queried as a further operating state value, wherein the internal combustion engine is stopped, when the collet is closed, only in the event that the charging state of the rechargeable battery lies above a predetermined minimum charge state. As a result, reliable operation of the electric motor is guaranteed when the internal combustion engine is stopped.
In a further development of the invention, a clamping pressure of the clamping apparatus is continuously queried as an operating state, wherein the internal combustion engine is stopped, when the clamping apparatus is closed, if the clamping pressure is greater than a predetermined minimum pressure. Preferably, a hydraulic oil temperature and/or an engine oil temperature of the internal combustion engine and/or an engine coolant temperature of the internal combustion engine is queried as an additional operating state. If a queried temperature lies below an assigned minimum temperature, the internal combustion engine is not shut off.
In an embodiment of the invention, the high pressure required for operation of the clamping cylinder is maintained independent of the operating state of the internal combustion engine, by means of the hydraulic pump, which is operated by an electric motor. As a result, startup of the internal combustion engine for production of the pressure required for operation of the clamping cylinder is avoided.
Other further developments and embodiments of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
In the drawings, wherein similar reference characters denote similar elements throughout the several views:
The underground construction device selected as an exemplary embodiment is configured as a vibrating pile-driving device 1, which is connected with a hydraulic assembly 2 in a hydraulic circuit 5. See
The hydraulic assembly 1 comprises an internal combustion engine, in the present case a supercharged diesel engine 21, which drives a hydraulic pump 22. The hydraulic pump 22 is connected with the hydraulic motor 14 of the vibrator gear mechanism 11 of the vibrating pile-driving device 1 by way of hydraulic lines 51 of the hydraulic circuit 5.
Furthermore, a second hydraulic assembly 4 (see
In the present arrangement, completely separate supply to the hydraulic motor 14 of the vibrator gear mechanisms 11 takes place by means of the hydraulic pump 22 driven by the diesel engine 21, on the one hand, as well as supply to the clamping cylinder 16 of the clamping apparatus 15 by way of the hydraulic pump 42 driven by the electric motor 41, on the other hand. In the case of configuration of the hydraulic pump 42 as a high-pressure pump, for example as a radial piston pump, the hydraulic pressure intensifier can be eliminated, as is shown in
In the exemplary embodiment according to
In the exemplary embodiment according to
Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19157538.0 | Feb 2019 | EP | regional |
