Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/03—Use of materials for the substrate
  • H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
  • H05K1/053—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an inorganic insulating layer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/02—Bases, casings, or covers
  • H01H9/06—Casing of switch constituted by a handle serving a purpose other than the actuation of the switch, e.g. by the handle of a vacuum cleaner
  • H01H9/061—Casing of switch constituted by a handle serving a purpose other than the actuation of the switch, e.g. by the handle of a vacuum cleaner enclosing a continuously variable impedance
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/03—Use of materials for the substrate
  • H05K1/05—Insulated conductive substrates, e.g. insulated metal substrate
  • H05K1/056—Insulated conductive substrates, e.g. insulated metal substrate the metal substrate being covered by an organic insulating layer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/52—Cooling of switch parts
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
  • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
  • H05K1/167—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed resistors

Definitions

• Carrier for an electrical circuit in particular for an electrical switch
• the invention relates to an electrical circuit arrangement according to the preamble of patent claim 1.
• Circuits arranged on a circuit board have a wide range of uses, for example in control devices, electrical household appliances or power tools.
• such circuits which serve to control an electric motor in an electric tool, are arranged with the circuit board in the housing of the switch for the electric tool.
• Such an electrical circuit arrangement consists of electrical and / or electronic components.
• the components are arranged on a carrier substrate, the conductor tracks for the electrical connection of the components also being located on the carrier substrate.
• a switch for a power tool, specifically for a cordless power tool, in the housing of which the carrier substrate of the control circuit is accommodated, is shown for example in DE 41 14 854 AI.
• the carrier substrate consists of a printed circuit board, for example using hard paper or FR4 technology, or also of a ceramic plate.
• Heat is generated in the components during the operation of the electrical circuit arrangement. This heat loss must be dissipated, which is done via the circuit board and a heat sink in order to prevent thermal damage to the components and thereby destruction of the circuit arrangement. It has it has been found that in circuit arrangements with higher heat loss, the printed circuit boards limit the effective dissipation of the heat. Particularly in the case of electrical switches for power tools with high power, in which a circuit arrangement for speed control, for torque cut-off or the like is arranged in the housing of the switch, there have been corresponding impairments up to the premature failure of the switch. This problem is particularly relevant for cordless power tools, where high currents flow through the switch.
• the invention is based on the object of creating an electrical circuit arrangement with improved heat dissipation.
• an electrical switch that is used, for example, in a high-performance power tool is to be improved in this regard.
• the carrier substrate consists of a metal part.
• An electrically insulating coating is applied to a surface of the metal part, in particular to the surface facing the components and the conductor tracks. At least one component and / or at least one conductor track are on the coating.
• the metal part preferably consists of aluminum or an aluminum alloy, for example an AlMg3 alloy.
• An anodized layer which in particular has a thickness of approximately 30 to 50 ⁇ m, is suitable as an electrically insulating coating.
• Such an anodized layer has both good thermal conductivity and good electrical insulation and is therefore particularly suitable for the circuit arrangement according to the invention.
• the metal part can also consist of another metal with good thermal conductivity, such as copper, steel or the like, or a metal alloy.
• the metal part is expediently designed as a plate, the thickness of which is, for example, at least 2 mm.
• a ceramic layer is suitable for the electrically insulating coating.
• the ceramic material which is in particular a ceramic paste, can be printed, rolled, sprayed or the like onto the surface of the metal part. If necessary, this layer can then be baked.
• a polymer layer such as an epoxy layer or the like, can also be used as an electrically insulating coating.
• the polymer material which is in particular a polymer resin, can be printed on, sprayed on, rolled on or the like on the surface of the metal part. If necessary, this layer is then hardened.
• a film in particular a plastic film, for the electrically insulating coating.
• the film material can be glued, laminated or the like onto the surface of the metal part.
• the coatings mentioned are characterized by simple manufacture. In addition, it is possible with such an electrically insulating coating to achieve an electrical dielectric strength of at least 400 V for direct current applications and an electrical dielectric strength of at least 2 kV for alternating current applications.
• the metal part itself is designed in the manner of a heat sink. Cooling fins can then be attached to the surface facing away from the electrically insulating coating.
• a metal part can be made from an extruded body.
• the thick-film technology lends itself to the simple production of the conductor tracks on the electrically insulating coating.
• the conductor tracks consist of copper, silver-palladium or the like, the paste, such as the copper paste, silver-palladium paste or the like, being applied to the coating in accordance with the layout for the conductor tracks.
• Printed resistors can also be applied to the coating using a resistive paste. The conductor tracks and / or the printed resistors are then burned in. The components can be soldered onto the electrically insulating coating in a vacuum. Often, at least one component of the circuit arrangement according to the invention is a power semiconductor, which results in increased heat loss.
• the coating can have a recess such that the power semiconductor is attached directly to the metal part, which in turn improves heat dissipation.
• the power semiconductor In order to avoid heat accumulation on the power semiconductor itself, it may also be appropriate to design the power semiconductor as an inaccurate chip, which has a bond connection to the conductor track on the coating.
• the power semiconductor can also be attached to the coating.
• the circuit arrangement according to the invention can be used particularly advantageously in an electrical switch.
• a switch is used above all in power tools, such as in a battery-operated power tool operated with direct voltage or in a power tool operated with alternating voltage.
• the switch has a housing in which the carrier substrate is arranged.
• the carrier substrate can just as well be arranged on one side of the housing, in particular as a housing part and / or lateral closure for the housing, so that the carrier substrate serves simultaneously as a carrier for the components and as a component of the housing.
• the carrier substrate can simultaneously serve as a heat sink, in that the surface of the metal part facing away from the coating projects out of the housing as a heat sink.
• Such a multifunctional part simplifies the switch and saves costs.
• the carrier substrate also serves as a housing part, it is advisable to design it non-planar and / or spatially in the manner of a base. This ensures simple handling when installing the switch.
• a further housing part which consists in particular of plastic, is placed in the manner of a cover. With a corresponding design, the cover can be placed sealingly on the base, with the result that the switch is dustproof.
• the power semiconductor such as a MOS-FET, a triac, a thyristor, a free-wheeling diode or the like, is often used to supply the arranged electrical current for the electric motor in the housing.
• the power semiconductor can in turn be attached by soldering onto the metal part. This enables effective heat dissipation from the inside of the switch, which increases the service life of the switch.
• a resistance track for a potentiometer can be applied to the coating by means of an egg-inflammable resistance paste.
• the advantages achieved by the invention are, in particular, that there is an improved heat dissipation from the circuit arrangement. As a result, the circuit arrangement operates more reliably. There are fewer premature failures and the service life of the circuit arrangement is extended.
• the electrical circuit arrangement according to the invention is used for an electrical switch, this is suitable for operation with high power.
• the circuit arrangement in the housing of the electrical switch can also be arranged in the powers where previously the circuit arrangement had to be arranged separately from the switch in the power tool, for example in the cooling air flow for the electric motor.
• FIG. 2 shows a section along the line 2-2 in FIG. 1, 3 shows a section as in FIG. 2 according to a further embodiment
• FIG. 4 shows a plan view of the carrier substrate according to FIG. 3 as an individual part
• Fig. 5 shows a section as in Fig. 2 according to another embodiment
• Fig. 6 shows a section as in Fig. 2 according to yet another embodiment.
• an electrical switch 1 can be seen, which is to be used for an electric tool, in particular for a cordless electric tool operated with DC voltage.
• the switch 1 has a housing 2, an actuator 16 designed in the manner of a pusher and movably arranged on the housing 2 for the manual actuation of the power tool by the user, an actuator 17 designed in the manner of a switching lever for switching the right-left rotation for the power tool and on the housing 2 arranged terminals 18 for electrical connection to the battery.
• a switch 1 can also be used for a power tool operated with AC voltage, if it is configured accordingly, as will be explained in more detail below.
• an electrical circuit arrangement 3 for controlling the speed of the electric motor in the power tool is arranged in the housing 2.
• the circuit arrangement 3 can also include a torque switch-off of the electric motor, which can be used, for example, for screwing work with the electric tool, or another functionality of the electric tool.
• the circuit arrangement 3 thus contains at least part of the control electronics for the electric motor of the power tool.
• the housing 2 accommodates in a known manner still further parts of the switch 1, such as the contact system or the like, but this is not shown further.
• the circuit arrangement 3 has electrical and / or electronic components 4, which are arranged on a carrier substrate 5.
• the carrier substrate 5 consists of a metal part 7.
• An electrically insulating, ie non-conductive coating 9 is applied to a surface 8 of the metal part 7, in particular to the surface 8 facing the components 4 and the conductor tracks 6.
• At least one component 4 and / or at least one interconnect 6 of the circuit arrangement 3 is located on the coating 9.
• the metal part 7 consists of aluminum or an aluminum alloy.
• An AlMg3 alloy, for example, has proven to be particularly suitable for this.
• the electrically insulating coating 9 then consists of an anodized layer on the surface 8 of the aluminum metal part 7.
• the anodized layer expediently has a thickness of approximately 30 to 50 ⁇ m, so that on the one hand there is good thermal conductivity from the components 4 to the metal part 7 and on the other hand good electrical insulation to the metal part 7 is given.
• the metal part 7 can also consist of copper, steel or another highly thermally conductive metal or a metal alloy.
• the electrically insulating coating 9 can consist of a ceramic layer.
• a ceramic paste can be used as the ceramic material, which is printed on, rolled on, sprayed on or otherwise applied to the surface 8 of the metal part 7. If necessary, the applied ceramic paste can then be baked into the surface 8.
• a polymer layer for example an epoxy layer, is also suitable for the coating 9.
• the polymer material can be printed, for example, as an uncured polymer resin on the surface 8 of the metal part 7, sprayed on, rolled on or applied in some other way. If necessary, the polymer material can then subsequently be cured in a known manner.
• a film, such as a plastic film, can also serve as the coating 9. The film material is then glued to the surface 8 of the metal part 7, laminated or applied in some other way.
• the coating 9 for DC applications can be designed in such a way that an electrical dielectric strength of at least 400 V is achieved.
• the coating 9 is produced in such a thickness that an electrical dielectric strength of at least 2000 V is achieved.
• the metal part 7 can have any shape, for example the shape of the fastening 15 in the housing 2.
• the metal part 7 will often be designed as a plate, which can be seen in more detail in FIG. 2.
• the thickness of the plate is expediently at least 2 mm in order to ensure good heat dissipation.
• the metal part 7 can also be designed in the manner of a heat sink.
• the metal part 7 has cooling fins 10 on the surface 8 ′ facing away from the electrically insulating coating 9, as shown in FIG. 3.
• the metal part 7 can be produced from an extruded body.
• the conductor tracks 6 can be produced on the electrically insulating coating 9 from copper, silver-palladium or the like.
• this material can be applied to the coating 9 in the manner of a thick-film technique as a corresponding paste, namely as a copper paste, silver-palladium paste or the like.
• the paste is applied in accordance with the structure required for the conductor tracks 6, for example by printing.
• the paste is then, if necessary, burned into the coating 9.
• the electrical resistors can be printed on using a resistance paste and baked into the coating 9. This can be seen from the resistance path 14 in FIG. 4.
• the components 4 are preferably soldered onto the electrically insulating coating 9 in a vacuum.
• the components can of course also be SMD components 19, as can also be seen in FIG. 4.
• at least one of the components is a power semiconductor 11, 12.
• the coating 9 has a cutout 13 in the region of the power semiconductor 11, 12 on the carrier substrate 5.
• the power semiconductor 11, 12 is fixed directly in the recess 13 on the metal part 7, which can be done for example by soldering. Since a comparatively large heat loss occurs in power tools 11, 12, this measure ensures that the heat loss can be dissipated effectively. If the heat dissipation is sufficient, the power semiconductor 11, 12 can of course also be attached to the coating 9.
• the power semiconductor 11, 12 can be designed as an inexact chip which, for example, has a bond connection to the corresponding conductor tracks 6 on the coating 9, but this is not shown further.
• the carrier substrate 5 is arranged in the housing 2 of the electrical switch 1.
• the carrier substrate 5 is located on one side of the housing 2.
• the surface 8 ′ of the metal part 7 facing away from the coating 9 can also protrude from the housing 2 as a heat sink, in particular with cooling fins 10, as is shown in FIG 3 can be seen.
• the carrier substrate 5 itself can be designed as a housing part. This housing part then serves as a lateral closure for the housing 2, so that the corresponding side wall in the housing 2 is omitted.
• the carrier substrate 5 serving as the housing part can be designed spatially and thus not planar in the manner of a base 20.
• a further housing part in the manner of a cover 21 is fitted, as shown in FIG. 5, with which a particularly simple assembly of the switch 1 is achieved.
• the cover 21 can be made of plastic in the usual way, while the base 20 consists of the metal part 7.
• a simple sealing between the base 20 and the cover 21 can be achieved by a corresponding design by means of a tongue and groove connection 22.
• an additional seal can also be arranged between the base 20 and the cover 21, but this is not shown further. If it is an electrical switch 1 for a cordless power tool with a high output, correspondingly high currents flow in the power electronics, which in turn entails a large amount of heat.
• the power electronics can also be accommodated in the electrical circuit arrangement 3 on the carrier substrate 5 in the housing 2.
• the power electronics in the circuit arrangement 3 contain at least one power semiconductor, such as a MOS-FET 11 for supplying current according to the set speed to the electric motor and / or a free-wheeling diode 12.
• the MOS-FET 11 and the free-wheeling diode 12 can also be arranged on the coating 9 , as can be seen in Fig. 2.
• the coating 9 has at least one recess 13 such that the power semiconductor 11, 12 is attached directly to the metal part 7, which is shown in more detail in FIGS. 3 and 4.
• the MOS-FET 11 and the freewheeling diode 12 have a common potential in the circuit arrangement 3.
• the large amount of heat generated by the two power semiconductors 11, 12 due to the high flowing electrical currents is then dissipated directly onto the carrier substrate 5 without further thermal resistance.
• only a few, namely three electrical connection points are required from the carrier substrate 5 to the actual contact system in the switch 1, which considerably reduces the assembly effort for the switch 1.
• the power semiconductors 11, 12 are expediently attached to the metal part 7 by soldering.
• the power semiconductor 11 can also be fastened in a recess 13 directly on the metal part 7 in the case of a switch 1 for a mains-operated power tool, if the heat development requires it.
• the power semiconductor 11 for supplying current is a triac or a thyristor corresponding to the speed of the electric motor.
• the Resistor path 14 generates a desired signal which corresponds to the speed of the electric motor selected by the user via the adjustment of the actuating member 16.
• the resistance track 14 is applied to the coating 9, for example, by means of a burn-in resistance paste.
• the invention is not restricted to the described and illustrated exemplary embodiments of a circuit arrangement 3 in the housing 2 of the electrical switch 1.
• This circuit arrangement 3 can also be arranged per se at another convenient location in the power tool.
• the invention also includes all professional developments within the scope of the property right claims.
• the invention can be used not only for electrical switches and power tools, but rather can also be used in circuit arrangements on carrier substrates for control devices, electrical household appliances, electric garden devices, machine tools or the like.
• electrical switch housing: electrical circuit arrangement: component: carrier substrate: conductor track: metal part, * V: surface (of metal part): (insulating) coating (on metal part) 0: cooling fins 1 MOS-FET / power semiconductor 2: free-wheeling diode / power semiconductor 3: Recess 4: resistance track 5: fastening (of metal part) 6: actuating element 7 actuating element 8: connecting terminals 9: SMD component 0: base 1: cover 2: tongue and groove connection

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)
• Insulated Metal Substrates For Printed Circuits (AREA)
• Push-Button Switches (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
• Multi-Conductor Connections (AREA)
• Switch Cases, Indication, And Locking (AREA)
• Electronic Switches (AREA)
• Relay Circuits (AREA)
• Structures For Mounting Electric Components On Printed Circuit Boards (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7678917

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (13)

Citations (4)

Family Cites Families (20)

• 2001
  • 2001-03-24 DE DE10114572A patent/DE10114572A1/de not_active Withdrawn
• 2002
  • 2002-03-20 DE DE10212449A patent/DE10212449A1/de not_active Withdrawn
  • 2002-03-22 DE DE50210352T patent/DE50210352D1/de not_active Expired - Lifetime
  • 2002-03-22 CN CNB028050886A patent/CN100349236C/zh not_active Expired - Fee Related
  • 2002-03-22 US US10/471,413 patent/US7313001B2/en not_active Expired - Lifetime
  • 2002-03-22 EP EP02732337A patent/EP1374266B1/de not_active Expired - Lifetime
  • 2002-03-22 JP JP2002575972A patent/JP4326219B2/ja not_active Expired - Fee Related
  • 2002-03-22 AT AT02732337T patent/ATE365371T1/de not_active IP Right Cessation
  • 2002-03-22 WO PCT/DE2002/001044 patent/WO2002078029A1/de not_active Ceased

Patent Citations (4)

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