Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
  • B23Q3/15—Devices for holding work using magnetic or electric force acting directly on the work
  • B23Q3/154—Stationary devices
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F13/00—Apparatus or processes for magnetising or demagnetising

Definitions

• Switching device for changing the amount and direction of the permanent magnetization of ferromagnetic bodies, e.g. of permanent magnets
• the invention relates to a switching device for changing the amount and direction of the permanent magnetization of ferromagnetic bodies, e.g. permanent magnets, with a pulse current generator circuit, which comprises an energy storage device, an ignition circuit and a controllable electronic switch designed as a gas discharge tube and having an ignition electrode, and with at least one coil suitable for receiving the ferromagnetic body and connected to the Impulsstrora generator circuit, and further a permanent magnet clamping device for clamping magnetically attractable workpieces with a plurality of permanent magnets arranged next to one another with respect to their poles and separated by walls.
• a pulse current generator circuit which comprises an energy storage device, an ignition circuit and a controllable electronic switch designed as a gas discharge tube and having an ignition electrode, and with at least one coil suitable for receiving the ferromagnetic body and connected to the Impulsstrora generator circuit, and further a permanent magnet clamping device for clamping magnetically attractable workpieces with a plurality of permanent magnets arranged next to one another with respect to their poles
• a magnetic body For polarization or for changing, in particular for reversing the polarity of the polarity of a permanent magnet, a magnetic body must briefly be exposed to a strong magnetic field that is opposite to the existing polarity.
• a strong and instantaneous magnetic field can be generated in a coil, for example an air coil, when a high pulse current flows through it.
• a discharge tube known for example as a thyratron or an ignitron, works as a controllable, gas-filled electrical.
• Valve ie as an electronic switch for discharging the energy store, and is on agile current gate, which includes a hot cathode, a cooling coil, control grid and control anodes and other valve elements, such as specially designed surfaces.
• This pulse generator circuit for changing or reversing the polarity of a ferromagnetic body is structurally complex, large and therefore relatively expensive.
• special measures for cooling a thyratron or ignitron for example water cooling, must be provided.
• the object of the invention is to provide a switchgear which is as small in construction as possible and which can be implemented with simple electrical circuitry, for briefly changing the magnetic field strength of a ferromagnetic body, in which energy storage devices with a large output can be discharged repeatedly with a long service life of the device.
• the gas discharge tube is a short flash lamp designed for high gas pressures.
• the flash lamp is a simple electronic component with small spatial dimensions, so that it can be integrated into the switching device in a space-saving manner.
• the lamp can be changed without any cooling Reverse the polarity of a ferromagnetic body switch required power and can be inexpensively compared to a thyratron.
• the switching frequency that can be achieved with the flash lamp is so great that its operability is guaranteed over several years. Such a switching device is therefore suitable
• the essential components of the switching device are determined only by a number of energy stores to be provided for the switching power and by the simple flash lamp. To achieve the switching capacity for a magnetic clamping plate with a size of approx. 20 x 45 cm, eight capacitors of 1,000 ⁇ F each with a charging voltage of 600 V are sufficient as energy storage.
• the energy storage circuit connected in parallel with the flash circuit and coil formed in the series circuit can be implemented in any conventional manner, for example with capacitors and rectifiers.
• the ignition device for igniting the lamp is also simple.
• the switchgear can be easily implemented with few mechanical components.
• the internal resistance of the flash lamp which forms with the reduced burn-up distance after ignition is so small that a particularly high pulse current for forming a strong magnetic field in the coil is achieved.
• the length of the burn-up distance also determines the burn-off time of the lamp, so that the pulse duration can be kept very small with a short burn-up distance. A change in the light emission of the flash lamp by reducing the length of its burn-up distance is of no importance, since the lamp works according to the invention as an electronic switch.
• the functional reliability of the flash lamp ie primarily the avoidance of auto-ignition, especially in the case of a short burn-up distance and / or high anode-cathode blocking voltage, can be particularly ensured in that the flash lamp is designed for high gas pressures formed therein.
• This can be done in a very advantageous manner the formation of a statically favorable, high-pressure glass body shape can be achieved by using a particularly pressure-resistant material, such as quartz glass, and / or by a pronounced wall thickness of the glass body.
• the flash lamp as the ignition electrode comprises an electrically conductive, translucent layer applied to it and / or an ignition wire arranged on its circumference, which e.g. can be realized in the form of a nickel wire winding.
• the ignition electrode can also be designed as a grid within the lamp. The formation of the ignition electrode can therefore be adapted to the production process of the flash lamp and / or can take place with regard to special electrical ignition properties.
• the lamp can be surrounded by a glare-free, translucent light cover.
• the flash lamp In order to achieve a particularly long service life of the flash lamp, it can be a quartz glass flash tube filled with a xenon mixture. Quartz glass tubes are particularly heat-resistant, so that hairline cracks that would lead to the escape of gas are avoided.
• another expedient embodiment of the invention consists in the switching device having a circuit for reversing the polarity of the coil connections with a has a further pulse current generator circuit comprising a second electronic switch in the form of a flash lamp, the corresponding output terminal pairs of the two Pulse current generator circuits are connected to each other in reverse with the coil connections.
• a relay-controlled changeover switch for example, can be used for the pulse current reversal through the coil (s).
• the holding device comprises a device for adjusting the size of the energy to be stored
• the flash lamp (s) can be switched through at the set stored energy.
• the flash lamp can thus discharge energy stores charged to different amounts of energy in a power range sufficient for the regulation. In this way, not only can the polarity reversal of the polarity of a ferromagnetic body in the coil be achieved, but it is also possible to specifically increase the magnetization of the body or, if necessary, to weaken it to zero.
• the invention can be implemented in a particularly advantageous manner for clamping devices of machine tools which serve for clamping magnetically attractable workpieces and which, according to their main purpose, should be as small as possible and should be inexpensive to manufacture and reliable in operation.
• Such known permanent magnet clamping devices include. Usually a plurality of poles arranged side by side and permanent magnets separated by walls, each second of which is surrounded by an air coil and which can be switched by applying a pulse current to the coil, a circuit for reversing the polarity of the coil connections being provided for repeated switching of the poles, while the permanent magnets in each case with respect to theirs Polarity are unchangeable, and they also have the switching device comprising the energy storage device and the controllable electronic switch for generating and switching the pulse current. Due to the inventive design of the electronic switch as a flash lamp according to the invention, such a clamping device can be designed in particularly small dimensions, and it comprises an extremely simple electrical circuit for its switching operation.
• FIG. 1 shows a structure of a switching device with a flash lamp using a circuit
• FIG. 2 shows a modified part of the device of FIG. 1 for forming a magnetic clamping plate
• FIG. 3 shows a modified part of the device of FIG. 1 for a lifting magnet
• Fig. 4 shows the simplified representation of a flash lamp
• Fig. 5 shows another embodiment of the switching device according to the invention.
• FIG. 1 shows the arrangement of a flash lamp 2 of short construction designed for high gas pressures in a switching device 1.
• electrolytic capacitors C are used, which are charged to their respective charging voltage, which can be, for example, in the range of approximately 150-600 V, via charging diodes D connected to an AC voltage source (for example 220 V).
• the series connection of flash lamp 2 and an air coil 3 is connected to the output terminals K1 and K2 of the energy storage device 10.
• An ignition circuit 4 for the flash lamp 2 comprises a capacitor C z , ohmic resistors R1 and R2, a transformer T and one
• T is connected to an electrically conductive layer 20 which is applied to the flash lamp 2 and which can be vapor-deposited and / or applied as a lacquer.
• the series maintenance of flash lamp 2 and air coil 3 are coil connections K3 and K4 with a switching device 5 polarity switchable.
• the terminals of a relay 51 are connected for a changeover switch 50, the input terminals of which are connected to the output connections K and K2 of the pulse current generator circuit 11 of the switching device 1 comprising the energy storage device 10, the flash lamp 2 and the ignition circuit 4.
• An AC voltage source and a control switch 52 are located in the control circuit of the relay 51.
• a permanent magnet 6 is located in the air coil 3.
• the capacitors C can each have further capacitors (not shown) connected in parallel.
• a correspondingly high pulse current is applied to it.
• the energy stores ie the electrolytic capacitors C
• the ignition capacitor C previously charged via the resistors R1 and R2 is momentarily released load.
• the voltage pulse that occurs is transformed by the transformer T into a secondary-side high-voltage pulse with which the electrically conductive layer applied to the flash lamp is acted on, so that the gas in the lamp 2 is ionized or ignited.
• the ignition voltage is, for example, approx. 2 kV.
• the internal resistance of the flash lamp 2 suddenly changes from infinite to a very low value (for example a few milliohms), which is determined by the nature of the flash lamp 2.
• a high short-term current pulse arises which, depending on the level of the charging voltage, can be in the range of approximately 50-300 A.
• the pulse current flows through the air coil 3 connected in series with the flash lamp 2 and generates a high, short-term electromagnetic field in it. In this way, the polarity of the permanent magnet 3 arranged in the air coil 6 is reversed.
• the briefly generated magnetic field counteracts the field of the permanent magnet 6 in the coil 3.
• the latter can either be rotated by 180 in the plane of the drawing in FIG. 1, or the connections of the air coil 3 are interchanged by the changeover switch 50 being switched over. In the latter case, there is the advantage that the permanent magnet 6 does not have to be removed from the air coil 3, rotated and brought back into it.
• the momentary on-state of the flash lamp 2 is ended when the voltage between the terminals K1 and K2 falls below a certain voltage during the discharge of the capacitors C. Then the blocking state of the lamp 2 is again present.
• circuits can be carried out approximately at intervals of 30 to 40 s. If a faster switching sequence is desired, the charging of the electrolytic capacitors can be briefly interrupted in a conventional manner, so that the lamp is faster can return to its high resistance state.
• the switching device 1 can also comprise a device (not shown in FIG. 1) for setting the size of the energy to be stored.
• Corresponding control circuits are known and are not the subject of the invention. It is essential, however, that the flash lamp according to the invention can be switched through in a voltage range which is suitable for the regulation or setting of the pulse current to be switched. In this way, a weak or strong change (polarity reversal) in the magnetization of the ferromagnetic body and also its demagnetization can be specifically set and carried out.
• the length of the flash lamp determines the size of the forward internal resistance and its burn-up time.
• the short design of the lamp 2 serves to obtain a high pulse power, i.e. to make the pulse current particularly large and short-term.
• the flash lamp is designed for high gas pressures so that the anode-cathode reverse voltage can be particularly high without the risk of lamp 2 auto-ignition.
• a flash lamp with a very short burn-up distance and with a particularly high gas pressure therefore has particularly good switching properties, as a result of which a very strong and particularly short-term magnetic field is generated in the coil.
• the lamp 2 can be surrounded by a glare-free, opaque light cover 21 (see FIG. 1). This light cover 21 shields the light emission that occurs during flashing, ie switching through, so that a disturbing perception of the flashing light is avoided.
• a housing of the switching device 1 which is sealed off in a light-tight manner can also be used alone or in addition.
• 2 shows a magnetic chuck 8 in section. Permanent magnets 64 are arranged alternately with permanent magnets 61 to 63, in that the magnets lie one behind the other on the pole side.
• the poles of two adjacent magnets are separated from one another by a wall 83.
• the permanent magnets 64 have a fixed, unchangeable polarity.
• the permanent magnets 61, 62 and 63 are surrounded by air coils 31, 32 and 33, respectively. These air coils 31 to 33 are connected in series via lines L.
• the connections of the series circuit are connected to the terminals K3 and K4 of the circuit of FIG. 1.
• the magnets and walls 83 are mounted on a plate 82 of the clamping device 8.
• the surface 81 of the magnetic chuck 8 forms the support for a magnetically attractable workpiece, not shown.
• the magnets 61, 62 and 63 arranged in the air coils 31, 32 and 33 are each polarity switchable, since the series connection of the air coils is in series with the flash lamp 2 of FIG. 1 via the terminals K3 and K4.
• the switch 50 is switched over by pressing the key 52, so that a briefly strong magnetic field in each of the air coils 31, 32.
• 33 opposes the polarity of the permanent magnets 61, 62 and 63 is generated.
• the switches S and 52 can be designed as a common switching element, the switch 52 being closed or opened when the switch S is actuated before the switch S is closed.
• the above-described regulation of the level of the pulse current makes it possible to set the field strength of the reversible permanent magnets 61, 62 and 63 in such a way that a very thin and flat workpiece is not deformed during clamping. This is achieved by setting a smaller pulse current for the magnetization.
• a particularly strong pulse current is set in the case of larger solid workpieces, so that the magnetic fields of the permanent magnets 61, 62 and 63 are correspondingly pronounced, as a result of which high holding forces are produced.
• a lifting magnet 9 is shown with a winding 30 as a coil and a core 60 made of magnetic material.
• the connections of the winding 30 are connected to the terminals K3 and K4 of the circuit of FIG. 1.
• Such a lifting magnet 9 can e.g. find use in an industrial robot. It is important to magnetize or demagnetize the core 60 as quickly as possible in order to spontaneously magnetically attract, repel or release a workpiece or component 90. Since the mechanical and structural design of the switching device according to the invention is simple, it can be used particularly advantageously in an industrial robot for the function shown.
• FIG. 4 shows the mounting of a flash lamp 2 in ceramic insulators 7, which are arranged on a mounting plate 70.
• An electrically conductive layer 20 is evaporated onto the surface of the flash lamp 2 and is connected to the secondary terminal Z of the ignition transformer T in FIG. 1.
• a cover 21 which is, for example, ring-shaped.
• this cover 21 is at a sufficient distance is arranged to the glass housing of the lamp 2 in order to avoid overheating and resulting damage to the switching device.
• the circuit 5 shows a switching device 1 'with a circuit or arrangement 5' for reversing the polarity of the polarity of the coil connections K3 and K4.
• the circuit 5 ' comprises a second identical pulse current generator circuit 11', which accordingly has an energy storage device 10 ', a flash lamp 2' and an ignition circuit 4 ' having.
• the output terminal K (cathode) of the circuit 11 and the output terminal K2 of the circuit 11 ' are connected to the coil terminal K3, while the output terminal K2 of the circuit 11' and the output terminal K '(cathode of the second flash lamp 2') to the coil terminal K4 are connected.
• the ignition key S is provided and for the ignition circuit 4 'an ignition key S' is provided accordingly.
• the circuits 11 and 11 ' are fed by a common AC voltage source.
• the impulse flow through the coil 3 can be generated either with the circuit 11 by closing the key S or with the circuit 11' by pressing the key S 'z in the manner described above.
• the current directions of the two pulse currents through the coil 3 are directed in opposite directions. Accordingly, the polarity reversal of the polarity of the permanent magnet 6 in the coil 3 is achieved by alternately actuating the ignition buttons Sz and S ' z , without the permanent magnet 6 having to be removed from the coil 3, rotated and brought back into it.
• the relay-controlled changeover switch 50 of FIG. 1 is eliminated.
• circuits 10, 4 and 10 ', 4' can also be particularly expedient to jointly form parts of the circuits 10, 4 and 10 ', 4' for the circuits 11 and 11 '.
• the circuits 11 and 11 ' can also be connected to different AC voltage sources and / or comprise a common device or correspondingly assigned different devices for setting the size of the energy to be stored.
• An energy storage device of the switching device can also comprise inductors as an energy store instead of capacitors or can be constructed with other suitable known electrical storage means.
• the ignition device can also be designed in any suitable manner to generate a high ignition voltage pulse.

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• 1981
  • 1981-05-14 DE DE3119435A patent/DE3119435C2/de not_active Expired
• 1982
  • 1982-05-05 US US06/459,601 patent/US4497011A/en not_active Expired - Fee Related
  • 1982-05-05 NL NL8220163A patent/NL8220163A/nl unknown
  • 1982-05-05 WO PCT/DE1982/000096 patent/WO1982004160A1/en not_active Application Discontinuation
  • 1982-05-05 GB GB08300279A patent/GB2112232B/en not_active Expired
  • 1982-05-05 EP EP82901496A patent/EP0078823A1/de not_active Withdrawn
  • 1982-05-13 IT IT48410/82A patent/IT1147892B/it active

Non-Patent Citations (1)

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