Patent Application
20130214928
The invention relates to a rock drilling rig comprising a drilling boom provided with a rock drill such that drilling can be carried out thereby at selected drilling sites. The rock drilling rig also comprises a combustion-engine-free drive equipment by which it may be transferred between drilling sites. The drive equipment of the rock drilling rig comprises at least one electric motor and an electric driving system and further a control unit, which comprises means for controlling load of the electric driving system. Additionally the control unit comprises a user interface with a speed controller.
Further, the invention relates to a method for transfer drive of the rock drilling rig, and a speed controller.
The field of the invention is described in more detail in the preambles of the independent claims of the patent application.
In mines there are used rock drilling rigs, by which boreholes are drilled at planned drilling sites. When drilling of the boreholes is completed, the mining vehicle is transferred to a next drilling site for drilling a new drilling fan or face. In particular, in underground mines it is advantageous to perform the transfer drive by means of power produced by an electric motor. The energy required by the transfer drive may be stored in a battery. During the transfer drive, electric components of drive transmission become loaded and heated. Overheating may damage the component. So, the highest power in the transfer drive has to be limited typically such that the temperature in the electric components of the drive transmission will remain within allowed limits. Because of power limitations the speed of the transfer drive has to be reduced, which decreases the performance of the rock drilling rig.
The object of the present invention is to provide a new and improved rock drilling rig, a method for transfer drive of the same, and further a speed controller.
The rock drilling rig of the invention is characterized in that load monitoring is arranged to allow an intentional overload of the electric driving system according to a predetermined control strategy; and that the over-load has a limited duration, whereby overheating of the components in the electric driving system is prevented and that a control unit is arranged to indicate to the operator transfer from a rated load state to an overload state.
The method of the invention is characterized by overloading an electric driving system during transfer drive intentionally and for a period of a limited duration; and making the operator of the rock drilling rig aware of an overload situation.
The speed controller of the invention is characterized in that the speed control element comprises at least one other control range, where the control takes place in an overload portion exceeding the rated load.
The idea is that the electric driving system of the rock drilling rig may be overloaded intentionally such that it momentarily operates at a higher load than the rated load. A further idea is that the overload situation is known to the operator, for instance, such that the situation is controlled by himself/herself or it is indicated to him/her in one way or the other.
An advantage is that the rock drilling rig may be temporarily run at higher power than in the designed normal operation. Thus, the question is about a sort of power booster that is available in transfer drive such that it is possible to manage special situations of short duration, which occur therein and require a lot of power. Hence, the electric driving system of the rock drilling rig need not be designed for those driving situations requiring high power, and consequently overdesigning of components is avoided. Thus, the electric driving system may employ electric components that are less expensive and smaller in size. Further, operability and safety of the system is improved by the fact that the operator is aware of the overload situation and therefore it does not cause surprising situations.
The basic idea of an embodiment is that the electric driving system comprises an electric drive motor, which may be a permanent magnet type motor, for instance. Further, the electric driving system includes an energy storage, such as a battery or a battery package, for storing energy for transfer drive. It also includes a frequency converter, by which revolutions and torque of the drive motor may be controlled. The electric driving system may also include a voltage converter and optionally other electric components.
The basic idea of an embodiment is that load monitoring allows overload of the electric driving system, when the operator selects an over-load mode in the user interface.
The basic idea of an embodiment is that the speed controller comprises at least a first control range and a second control range. In the first control range the electric driving system may be loaded such that the rated load of the components is not exceeded. The first control range thus covers the normal state. The second control range, in turn, allows the rated load of the electric driving system components to be exceeded. The second control range thus covers an overload state. It will be easier for the operator to operate, when the load states are divided into separate control ranges. In that case, the operator will not move over to use the overload state without knowing about it.
The basic idea of an embodiment is that in the user interface of the control unit the operator is displayed the overload of the electric driving system being selected. Thanks to this application the operator is aware of an overload situation at all times.
The basic idea of an embodiment is that in the user interface the operator is displayed load monitoring information of the electric driving system, such as duration of overload situation, time left for overload situation, increase in performance provided by overload, increase in torque provided by overload and temperature of the most critical component in the electric driving system.
The basic idea of an embodiment is that the rock drilling rig comprises at least one cooling system, by which one or more electric components of the electric driving system are cooled. The control system may increase cooling of one or more components, when transition to an overload mode takes place. The cooling system may be a liquid cooling system, in which electric components are cooled with a cooling liquid. The cooling system may also be switched on in advance, when it is known that an overload situation will arise. Further, it is also possible to prepare for forthcoming overload by enhancing the cooling of one or more critical components in advance. By means of cooling the temperature in the components may be kept better under control in an overload situation, thanks to which the duration of the overload may be prolonged.
The basic idea of an embodiment is that the control unit automatically switches on an overload mode, in case a power request from the operator requires that. The control unit monitors power requests provided by a speed controller or a corresponding control element and assesses on the basis thereof, whether the power request is in compliance with the rated load, or whether there is a need to transfer to the overload mode. The control unit indicates the transfer from the rated load mode to the overload mode to the operator, whereby the operator becomes aware of the change.
The basic idea of an embodiment is to allow an overload situation only if the operator has deliberately accepted it. In that case the operator will never use the apparatus accidentally in overload mode.
The basic idea of an embodiment is that the electric driving system comprises at least one temperature sensor for monitoring the temperature of at least one critical component of the electric driving system. The load monitoring considers the temperature information when determining the allowed duration of the overload state.
The basic idea of an embodiment is that the load monitoring is arranged to discontinue overload mode, when one or more of the following predetermined limits has been reached: the maximum temperature set for one or more of the critical components of the electric driving system; the maximum temperature set for any one component of the electric driving system; the maximum duration calculated for the overload state. In this embodiment the control unit takes care that the overload will not cause damage to the components of the electric driving system. Thanks to the automatic monitoring the operator's responsibility and mental stress will reduce in the transfer drive.
The basic idea of an embodiment is that the load monitoring is arranged to notify the operator in advance prior to discontinuation of over-load state. In that case the operator may prepare himself for the extra power booster employed to be discontinued. Thus, it is possible to avoid dangerous situations caused by sudden power reductions, for instance.
The basic idea of an embodiment is to allow overload of the electric driving system in any one of the following transfer drive situations, where a lot of torque and electric power are required: drive over an obstacle; acceleration to base speed of transfer drive; steep uphill drive; drive over a pothole; drive onto a transportation platform; downhill drive of long duration.
The basic idea of an embodiment is that a speed control element included in the speed controller comprises at least a first control range and a second control range. In the second control range, the movement of the control element has a response that differs from the movement response of the first control range. The manoeuvring of the control element in the second control range may be stiffer, for instance, than manoeuvring in the normal, first movement area. Further, the scaling of the control element movement may be different in the first and the second movement areas.
The basic idea of an embodiment is that the speed controller comprises at least one detector that detects transfer to the second control range. The speed controller, the control unit or the user interface produces a sound signal, a visual message or a vibration alarm when transfer to an over-load state takes place.
The basic idea of an embodiment is that when the transfer drive is performed downhill, the electric drive motor is switched to operate as a generator. In that case the drive motor decelerates the rock drilling rig during the downhill drive and simultaneously generates electric current, which is primarily used for charging the energy storage of the rock drilling rig. Surplus electric energy generated in deceleration may be converted to thermal energy in electric brake resistors. In addition to this, by means of the surplus electric energy produced in deceleration it is possible to operate one or more hydraulic systems in the rock drilling rig, whereby all the surplus electric energy need not just be wasted through brake resistors. This improves the dynamics of the electric driving system in downhill drive. When there is one or more systems, in addition to the brake resistors, to receive surplus energy, it is possible to over-load the brake resistors momentarily during downhill drive. This application enables a kind of brake booster, which is available for a limited duration.
Some embodiments will be explained in greater detail in the attached drawings, in which
a to 4c show schematically some speed controllers and means in connection therewith for transfer to an overload situation and detection thereof,
In the figures, some embodiments are shown in a simplified manner for the sake of clarity. Similar parts are denoted with the same reference numerals in the figures.
At drilling site P one or more boreholes are drilled with the rock drilling rig 1. When the tasks assigned for the drilling site P are completed, the rock drilling rig 1 is transfer-driven away from the drilling site P to a new drilling site or somewhere else, for instance to be serviced. The rock drilling rig 1 is provided with drive equipment 16 which does not include a combustion engine, i.e. it is combustion-engine-free. Instead, the drive equipment 16 includes one or more electric engines M, which generate the power required in the transfer drive. The electric motor M may be coupled to a gearbox 17; wherefrom rotating power is transmitted through shafts or corresponding transmission elements 18 to one or more wheels 19. The energy required in transit drive may be charged to an energy storage B, which may be a battery, for instance. The drive equipment 16 may additionally include one or more control devices S and one or more brake resistors 20. The drive equipment 16 thus comprises a plurality of electric components K, which affect the transfer drive. These components K are loaded during transfer drive and they generate heat, the degree of which is relative to the electric energy passing through each component. As is commonly known, electric components have temperature limits that should not be exceeded, or otherwise a consequence could be a damaged component. In order to protect the components K, a rated load is generally determined for them, and normally they should be used at lower load than that. The control unit C may comprise load monitoring KV that is arranged to monitor the load in one or more components K included in the drive equipment 16 and connected to the electric driving system. By means of the load monitoring KV it is possible to avoid damaging of the electric driving system and other default and dangerous situations resulting from the load.
Further, the rock drilling rig 1 may be provided with a liquid cooling system 21, by which it is possible to cool the electric components K included in the driving system 16, as will be described below.
In this application the frequency converter refers to a control means, by which the revolving speed of the electric drive motor may be controlled in a stepless manner. The frequency converter may be an inverter or it may be a DC/AC converter, which controls the running of the electric motor.
In
The components K of the drive equipment 16 may be provided with temperature sensors L, and the information obtained therefrom may be conveyed to the control unit C and the load monitoring KV.
It appears from
a to 4c show in a highly simplified manner some speed controllers 50 having a speed control element 51, by which the operator may transmit a request to the control unit C so as to affect the driving speed and performance.
In
a illustrates that the speed control element 51 may have different resistances of movement in the first control range 53 and the second control range 54. The resistance of movement of the speed control element 51 may be affected by spring members 55 and 56, or alternatively, it is possible to use an electric or pressure-medium-operated actuator so as to provide the resistance of movement. When the speed control element 51 is moved in the first control range 53, its movement is resisted only by the first spring member 55. When the speed control element 51 is moved more and transition to the second control range 54 takes place, the second spring member 56 starts affecting it as well. The second control range 54 has clearly higher resistance of movement F2 than the resistance of movement F1 in the first control range 53, and consequently the operator will not unintentionally move over to a control mode, where overload of components K is allowed.
In
The speed controller 50 of
One optional speed controller application may be such that moving the speed control element 51 to the second control range 54 is possible only after selecting an overload mode by means of a switch or a display device.
Even though the drive equipment of the rock drilling rig is completely without a combustion engine, the carrier of the rock drilling rig may comprise a reserve power unit, which may comprise a combustion engine. This combustion engine drives a generator for producing electric energy. The reserve power unit is not included, however, in the drive equipment, and it is only intended for use in special situations, for instance when the battery is flat or damaged.
In some cases, features disclosed in this application may be used as such, irrespective of other features. On the other hand, features disclosed in this application may, if required, be combined to form various combinations.
The drawings and the related description are only intended to illustrate the idea of the invention. Details of the invention may vary within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20105579 | May 2010 | FI | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FI2011/050468 | 5/24/2011 | WO | 00 | 3/12/2013 |
