The invention relates to a drive system for driving a crusher of a material crusher plant having a main drive and a power transfer unit driven by the main drive, wherein the power transfer unit drives at least one generator and a first hydraulic pump, which is connected to the power transfer unit in a shiftable manner.

The invention further relates to a method for operating a crusher of a material crusher plant having a drive system driving the crusher, wherein the drive system comprises at least one main drive and a power transfer unit.

Such crushers are used in material crusher plants as mobile or stationary units for crushing, for instance, natural stone or recycled materials such as concrete, bricks, demolition rubble and the like. The material to be crushed to a specified size is fed into the crusher. The latter can be designed as an impact crusher. In such an impact crusher, the material to be crushed is seized by a fast-running rotor, accelerated and thrown onto a stationary impact mechanism until it has been crushed to the desired grain size. In a cone crusher, crushing is performed in a continuously opening and closing crushing gap between a crushing hopper and a crusher spindle. The crusher spindle rotates along an eccentric trajectory. Jaw crushers, in which the crushed material is crushed in a wedge-shaped slot between a fixed jaw and a crusher jaw moved by an eccentric shaft, are also used.

The high forces required to crush the material are a common feature of such crushers. Accordingly, they are of a mechanically stable design. As a result, large masses have to be moved with correspondingly large mass moments of inertia. The crushers are driven by powerful drives adapted to the crushers, if necessary with the interposition of a mechanical transmission. To enable the drive, which may be designed as a diesel engine for instance, to be ramped up, a clutch, for instance a frictional clutch, is provided between the drive and the crusher, which clutch can be used to interrupt and establish the torque and power transmission. The clutch can also be actuated in the event of a blockage of the crusher. Ramping up the crusher results in high mechanical and thermal stresses on the clutch when it is engaged and the speed of the crusher is slowly adapted to the speed of the drive or a transmission output shaft of an intermediate transmission.

DE 102015118398 A1 describes a drive device and a machine device plus a method for ramping up the drive device and the machine device. The machine may be a crusher driven by the drive device via a belt drive. A main drive designed, for instance, as a diesel engine is connected to a gearbox via a gearbox input shaft. A clutch is downstream of the transmission, which clutch is used to connect the transmission to the belt drive via a transmission output shaft. Actuating the clutch can interrupt or establish the flow of torque between the transmission input shaft and the transmission output shaft. The clutch can be engaged and disengaged, for instance, by hydraulic or pneumatic pressure, electromagnetic force, spring force or mechanical operation. An auxiliary drive, which is designed to drive the transmission output shaft is assigned to the drive device or the machine device. To ramp up the drive device or the machine device, the main drive can be started with a disengaged clutch and the speed increased to a specified value. Simultaneously, the auxiliary drive can accelerate the transmission shaft and thus the driven machine to a specified engagement speed. Upon achieving this speed, the clutch is engaged and the auxiliary drive is switched off. The machine is then driven by the main drive. Hydraulic pumps are connected to the transmission, either directly or via individual clutches, which are driven by the main drive via the transmission.

The auxiliary drive thus accelerates the high mass of the machine before it is coupled to the main drive. In this way, a high load on the clutch can be avoided when the clutch is engaged. A disadvantage is, however, that in addition to the main drive, a further drive (auxiliary drive) is mandatory. This results in an increased number of components and thus increased costs. Furthermore, space inside the machine device must be provided for the auxiliary drive, which is not always possible, particularly in the cramped confines of mobile machine devices.

From EP 2 500 100 A1, a drive device for a machine device and the associated machine device are known. The drive device comprises at least one drive means, a pump power transfer unit, a hydraulic pump, a fluid coupling and a v-belt pulley. The drive means drives the pump power transfer unit and, via that, the hydraulic pump and the v-belt pulley. A clutch and the fluid coupling are interposed between the pump power transfer unit and the v-belt pulley. The clutch is located upstream of the fluid coupling. The machine to be driven can be a crusher of a construction machine, for instance. The driven machine therefore has a high mass inertia. The clutch is used to interrupt or connect the flow of torque between a gearbox input shaft and a gearbox output shaft of the pump power transfer unit. It can be actuated by hydraulic or pneumatic pressure, by an electromagnetic force, a spring force or mechanical operation. The fluid coupling arranged in series with the clutch is based on the Föttinger principle. The fluid coupling results in the downstream components having a high mass inertia being accelerated gently putting only little stress on the clutch. The disadvantage of this arrangement is that two couplings are provided, to wit the clutch and the fluid coupling. This results in increased manufacturing costs in addition to higher operating costs and maintenance costs of the machine device.

The invention therefore addresses the problem of providing a drive system for a crusher, which, at a reduced number of required components, permits a gentle ramping-up of the crusher and an interruption of the transmission of torque and power.

The invention further addresses the problem of providing a corresponding process for operating a crusher.

The invention addresses a problem in relation to the drive system, which is solved by installing a shiftable fluid coupling in the transmission path from the power transfer unit to the crusher, by interconnecting the shiftable fluid coupling and a pump in a fluid conveying manner in a pump circuit and by supplying a fluid to the shiftable fluid coupling by means of the pump. Opening the shiftable fluid coupling interrupts the transmission of torque and power from the main drive to the crusher. In this way, the main drive can be started without power being transferred to the crusher. By engaging the shiftable fluid coupling, torque and/or power is transferred from the main drive to the crusher via the power transfer unit. In that way, the shiftable fluid coupling permits a smooth start of the crusher. The shiftable fluid coupling absorbs extreme load peaks and torsional vibrations. In case of overload or blockage situations, the shiftable fluid coupling can be rapidly opened. This results in an effective overload protection. In that way, the shiftable fluid coupling combines the advantages of a shiftable, frictional clutch and a non-shiftable fluid coupling downstream thereof, as known from the state of the art, in one component.

According to a particularly preferred design variant of the invention, provision may be made that the transmission of torque and/or power of the shiftable fluid coupling can be adjusted by adjusting the filling quantity of the fluid in the shiftable fluid coupling. Besides the pure shifting operation for the transmission of torque and power, the torque transmitted by the clutch can be specified without slippage or with minimum slippage by adjusting the fluid level in the shiftable fluid coupling accordingly. A higher fluid level permits the transmission of a greater torque.

Particularly preferably provision may be made that in a first operating state of the drive system, the volume flow of the fluid supplied to the fluid coupling is greater than the volume flow discharged, that in a second operating state of the drive system, the volume flows of the supplied and discharged fluid are identical and that in a third operating state, the volume flow supplied to the fluid coupling is smaller than the volume flow discharged. In doing so, the supply and the discharge of the fluid to and from the pump can also be completely interrupted. If the volume flow supplied to the fluid coupling is greater than the volume flow discharged, the fluid level inside the shiftable fluid coupling rises. This permits the shiftable fluid coupling to transmit a higher torque. If the volume flow supplied and the volume flow discharged are identical, the torque that can be transmitted by the fluid coupling remains unchanged. A volume flow of 0 m3/min or volume flows differing from 0 m3/min but being identical can be provided for the supplied and discharged volume flows. If the discharged volume flow is selected to be greater than the supplied volume flow, the transmissible torque can be reduced. The transmission of torque and/or power can be interrupted if the shiftable fluid coupling is completely or at least almost completely drained.

A simple and reliable interruption of the inflow or discharge of the fluid to or from the shiftable fluid coupling can be achieved by arranging at least one valve to interrupt the flow in the pump circuit of the fluid. If, for instance, it is intended that a valve is arranged in the supply line of the shiftable fluid coupling, the supply of the fluid to the shiftable fluid coupling can be interrupted. If the fluid continues to flow out of the shiftable fluid coupling, the level of the fluid inside the shiftable fluid coupling can be quickly reduced in this way, thereby reducing or interrupting the transmission of torque or power.

It can be advantageous to have the power transfer unit drive the pump or to have the main drive shaft drive the pump. In this way, the pump is driven continuously while the main drive is running, irrespective of the fluid level of the shiftable fluid coupling. In this way the fluid level of the fluid coupling can be adjusted in all operating situations in which the main drive is running. A pump driven by the power transfer unit is more accessible, simplifying installation and maintenance.

According to a preferred design of the invention, provision may be made that the shiftable fluid coupling has drilled holes, through which the fluid is routed out of the shiftable fluid coupling because of the centrifugal force present inside the shiftable fluid coupling and is subsequently routed to the pump. When the main drive and thus the shiftable fluid coupling is rotating, fluid is permanently discharged from the shiftable fluid coupling. The fluid level inside the shiftable fluid coupling can be adjusted by controlling the inflow of fluid.

To be able to increase the fluid level inside the shiftable fluid coupling, it can be provided that the delivery rate of the pump is greater than the volume flow through the drilled holes of the shiftable fluid coupling caused by the centrifugal force. In this way, the fluid level of the fluid can be increased inside the shiftable fluid coupling in spite of the permanent discharge of the fluid from the shiftable fluid coupling. By reducing the delivery rate of the pump, the fluid level inside the shiftable fluid coupling can be reduced. The flow of fluid to the shiftable fluid coupling can be particularly advantageously controlled or regulated by a valve located between the pump and the shiftable fluid coupling. The pump can then be operated at constant pumping capacity. The fluid level is adjusted by controlling or regulating the volume flow supplied to the shiftable fluid coupling by means of the valve. In the simplest case, a control valve having binary behavior can be provided, which can be moved between an open and a closed position. Opening the valve increases the fluid level in the shiftable fluid coupling and in that way its capability to transmit torque and power. By closing the valve, the fluid level is rapidly reduced in proportion to the discharge of fluid from the shiftable fluid coupling. This permits, for instance, a rapid interruption of the transmission of torque and/or power if the crusher is blocked. A control valve can be used to easily set a minimum and maximum level in the shiftable fluid coupling. It is also conceivable to set intermediate fluid levels and in that way a desired transmission capacity of torque and/or power of the shiftable fluid coupling based on an correspondingly clocked activation of the shifting valve.

It is also possible to provide a proportional valve in the conveying line between the pump and the shiftable fluid coupling. Such a proportional valve can be used to easily adjust the fluid level of the shiftable fluid coupling to maximum, minimum and intermediate levels.

Provision may be made to quickly interrupt the transmission of torque and/or power from the main drive to the crusher in the event of an overload or blockage of the crusher, thereby preventing the main drive from stalling or damage to the blocked components of the drive system or the crusher from occurring, in that a control unit is assigned to the drive system, and in that the control unit is designed to detect an overload and/or a blockage of the crusher and, in the event of a detected overload and/or blockage, to output a control signal, which causes the pump to be switched off and/or the supply of fluid to the shiftable fluid coupling to be interrupted.

A safe start of the main drive and a smooth ramping-up of the crusher can be achieved by designing the control unit to control the pump and/or the valve such that the filling quantity of the fluid in the shiftable fluid coupling increases when the rotational speed of the main drive is increased after the start thereof and/or when the rotational speed of the crusher is increased. The increase in the filling quantity continuously increases the transmission of torque and/or power of the shiftable fluid coupling, thereby reliably preventing an overload of the main drive. Preferably, the complete filling of the previously drained, shiftable fluid coupling is performed inside a period of 5 to 60 s, particularly preferably inside a period of 10 to 20 s.

To be able to drive further aggregates, for instance a hydraulic motor for moving a mobile material crusher unit, in which the drive unit and the crusher are integrated, provision may be made that at least one second hydraulic pump is connected to the power transfer unit in a non-shiftable manner and driven thereby.

Particularly advantageously, provision may be made that the drive system drives the crusher via a belt drive and that a drive pulley of the belt drive is connected to the shiftable fluid coupling of the drive system. The belt drive can transmit the torque or power from the power transfer unit to the crusher along a sufficiently great distance. It permits setting a suitable transmission ratio, compensates for impact loads and is easy to install and maintain. However, it is also conceivable to provide other transmission elements between the drive system and the crusher, such as a gear drive, chain drive, shaft or similar.

If it is intended to assign an auxiliary drive to the drive system, which auxiliary drive is directly or indirectly in operative connection to the crusher in the power transmission direction of the main drive downstream of the shiftable fluid coupling, then the crusher can be operated in the opposite direction to the work-flow direction, for instance in case of a blockage or for maintenance purposes. It is also conceivable to use the auxiliary drive to support the crusher during ramping-up.

A simple design of the auxiliary drive can be achieved by designing the auxiliary drive as a hydraulic motor and by having a hydraulic pump driven by the power transfer unit drive the hydraulic motor. In this way, the energy of the auxiliary drive is thus supplied by the main drive.

By arranging a cooler in the pump circuit of the fluid of the shiftable fluid coupling, through which the fluid flows, excessive heating of the fluid can be prevented. This is a major advantage over non-shiftable, constantly filled fluid couplings, in which efficient cooling of the fluid used is not possible or only possible to a limited extent.

In order to enable the fluid level of the fluid inside the shiftable fluid coupling to be adjusted by varying the inflow and/or discharge of the fluid into and out of the shiftable fluid coupling accordingly, it can be provided that an interim storage tank for the fluid is arranged in the pump circuit of the fluid, in particular in the return flow of the fluid from the shiftable fluid coupling to the pump. If, for instance, the supply to the shiftable fluid coupling is interrupted, the fluid can drain out of the shiftable fluid coupling and is collected in the interim reservoir. In this way the shiftable fluid coupling can be drained. Accordingly, fluid can be removed from the interim reservoir and fed to the shiftable fluid coupling for filling the shiftable fluid coupling.

The problem addressed by the invention in relation to the method is solved by arranging a shiftable fluid coupling between the power transfer unit and the crusher, by reducing the fluid level of the fluid in the shiftable fluid coupling in the event of a blockage of the crusher and/or for starting the main drive, and by increasing the fluid level of the fluid while the crusher is ramped-up. Reducing the level can influence the transmission of torque and/or power of the shiftable fluid coupling. Draining the fluid from the shiftable fluid coupling can completely interrupt the transmission of torque and/or power. This permits the main drive, which can be a diesel engine, for instance, to be started and ramped up. Raising the fluid level inside the shiftable fluid coupling continuously increases its transmission of torque and/or power. This permits a smooth ramping-up of the crusher. In case the crusher is overloaded or blocked, the fluid can be quickly discharged from the shiftable fluid coupling. This reduces or interrupts the transmission of torque and/or power. This measure can prevent the main drive from stalling and prevents the main drive, the crusher or any other component from being damaged in case of a blockage. The shiftable fluid coupling thus performs the task of a known combination of a clutch and a constantly filled fluid coupling downstream thereof.

