Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans
  • H02K7/145—Hand-held machine tool
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/22—Arrangements for cooling or ventilating by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges
  • H02K9/223—Heat bridges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/008—Cooling means
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
  • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
  • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/10—Casings or enclosures characterised by the shape, form or construction thereof with arrangements for protection from ingress, e.g. water or fingers
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
  • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/02—Arrangements for cooling or ventilating by ambient air flowing through the machine
  • H02K9/04—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium
  • H02K9/06—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium with fans or impellers driven by the machine shaft
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/22—Arrangements for cooling or ventilating by solid heat conducting material embedded in, or arranged in contact with, the stator or rotor, e.g. heat bridges
  • H02K9/227—Heat sinks

Definitions

• the invention relates to an electric motor with a stator and a rotor according to the type defined in more detail in the preamble of Claiml.
• a generic electric motor is known from DE 10 2007 060 01 1 A1.
• WO 2007/028684 A1 describes an electric motor with a stator and a rotor that is non-rotatably connected to a shaft.
• the shaft is mounted in a bearing that is received in a bearing shield.
• An air gap is provided between the end shield and the shaft, which takes over part of the heat conduction from the rotor.
• Such brushless, a rotor equipped with permanent magnets having electric motors are often encapsulated in order to protect the rotor from contamination, in particular from metal dust, which is attracted by the permanent magnets. Due to magnetic reversal effects in the rotor and due to the heat transfer from the stator to the rotor, the rotor in such electric motors usually heats up very strongly. A particular problem here is that with increasing power of the electric motor, the temperature of the rotor also rises and that the high temperatures that result inside the electric motor can damage the permanent magnets. Due to the encapsulation of the motor and in particular the rotor, it is very difficult to keep the rotor at an acceptable temperature.
• the heat dissipation element according to the invention attached to the rotor package ensures that if the rotor heats up during operation, the heat is reliably dissipated and overheating of the rotor is avoided.
• the gap seal present between the heat dissipating element and the component connected to the stator prevents contaminants, such as metal dust, from reaching the rotor. As a result, the rotor is encapsulated without having to worry about overheating.
• the fact that the gap seal is formed between the heat dissipating element and a coil body connected to the stator means that existing components are sensibly used, so that no additional costs are required to form the gap seal.
• the heat dissipation element consists of a material with a high thermal conductivity.
• a structurally particularly advantageous embodiment of the invention can consist in that the heat dissipating element is attached to a flat surface of the rotor core.
• the heat dissipation element is connected to a fan wheel or is designed in one piece with a fan wheel.
• the coupling of the fan wheel to the heat dissipation element results in a substantial increase in the surface area of the heat dissipation element, so that a correspondingly larger amount of heat can be dissipated from the rotor.
• This heat dissipation from the rotor can be increased even further if the fan wheel is made of a material with a high thermal conductivity.
• the distance between the component connected to the stator and the heat dissipating element for forming the gap seal is 0.05 to 1 mm, preferably 0.3 to 0.6 mm.
• Such a size of the gap seal prevents, on the one hand, the penetration of impurities into the area of the rotor and, on the other hand, enables air to flow through, so that the cooling of the rotor is ensured.
• An electric hand tool device with an electric motor according to the invention is specified in claim 8.
• Such an electric hand tool which can be designed as an angle grinder, for example, can be operated with very high powers due to the good dissipation of heat from the electric motor described above.
• an air gap is present between the stator and a housing surrounding the stator.
• FIG. 1 shows a section through an electric hand tool device according to the invention with an electric motor according to the invention.
• Fig. 1 shows an electric hand tool device 1, which is formed in the present case as an angle grinder.
• the electric hand tool device 1 could also be designed in some other way, for example as a flange drill, jigsaw or the like.
• the electric hand tool device 1 has an electric motor 2, in the present case a brushless electric motor 2.
• the electric motor 2 in turn has a stator 3 and a rotor 4 arranged within the stator 3.
• the electric motor 2 is an electric motor 2 operated on the normal mains supply, which is electrically well insulated compared to an electric motor operated by means of batteries, which usually increases the problems described above with regard to high temperatures of the rotor 4.
• the stator 3 has a coil body 6 which is also known per se.
• the rotor 4 is, as is customary in a brushless electric motor 2, equipped with permanent magnets 7, which are surrounded by sheet metal or a rotor package 8 in a manner also known per se.
• a rotor shaft 9 runs through the rotor 4 and drives an output shaft 11 of the electric hand tool device 1 via a transmission 10.
• the rotor shaft 9 is mounted in a housing 12 of the electric hand tool device 1 by means of two bearing arrangements 13 spaced from one another.
• the housing 12 of the electric hand tool device 1 is formed in two parts and has a motor housing 12a and a gear housing 12b. This enables the drive components of the electric hand tool device 1, in particular the electric motor 2 with its components, the transmission 10, the output shaft 11 and the bearing arrangements 13 to be assembled.
• a heat dissipating element 14 is attached to the rotor assembly 8 of the rotor 4.
• the heat dissipating element 14 is preferably made of a material with a high thermal conductivity, for example aluminum, and is used to remove heat from the rotor 4.
• the heat dissipating element 14 should consist of a non-magnetizable material in order to avoid magnetic short circuits of the rotor 4.
• the preferably rotationally symmetrical heat dissipation element 14 is attached to a plane surface 8 a of the rotor core 8 in the present case. In other words, the heat dissipating element 14 is arranged in the axial extension of the rotor core 8 to.
• the heat generated in the rotor 5 is dissipated via the rotor package 8 to the heat dissipating element 14.
• the heat dissipating element 14 can also be used in places other than at Flat surface 8a has one or more contact surfaces with the rotor package 8, for example in that the heat dissipating element 14 has one or more projections which engage axially in the rotor package 8.
• the heat dissipation element 14 can also be made in several parts or one or more further components can be arranged between the heat dissipation element 14 and the rotor package 8, which in this case should have a heat-conducting property.
• the heat dissipating element 14 can be attached to the rotor assembly 8 with a suitable, preferably heat-conductive adhesive. Between the heat dissipating element 14 and the rotor shaft 9 is an insulating mate rial 15 in the present case, which ensures electrical insulation of the heat dissipating element 14.
• the heat dissipating element 14 can also be used for balancing the rotor 4, in that depressions or similar material removals are introduced into the same or are made on the same.
• a gap seal 16 is formed, which prevents impurities, such as metal dust, from penetrating into the area of the rotor 4 and especially in the area of permanent magnets 7, prevented.
• the distance between the component connected to the stator 3, i. H. the coil body 6, and the heat dissipating element 14 0.05 to 1 mm, preferably 0.3 to 0.6 mm. A good seal can thus be achieved over the length of the gap formed between the coil body 6 and the heat dissipating element 14.
• the rotor 4 or the rotor package 8 and the permanent magnets 7 are also encapsulated, namely in that the coil body 6 is connected to a bearing flange 17 and thus prevents the ingress of contaminants from this side as well.
• One of the two bearing arrangements 13 is accommodated in the bearing flange 17.
• a fan wheel 18 connects to the heat dissipating element 14 and is arranged on the rotor shaft 9.
• the heat dissipation element 14 is provided with an inflow geometry, which in the present case is designed as a rounding, which improves the inflow of air into the fan wheel 18.
• the inflow geometry of the heat dissipating element 14 begins with the end of the coil body 6, which is axially shorter than the heat dissipating element 14.
• the heat dissipation element 14 can be connected to the fan wheel 18.
• the heat given off by the rotor package 8 to the heat dissipating element 14 is at least partially passed on to the fan wheel 18, from where it can be given off to the air flowing through the housing 12 of the handheld power tool 1.
• the fan wheel 18 is preferably made of a material with a high thermal conductivity, for example aluminum, and can also be used to balance the rotor 4.
• the fan wheel 18 can also consist of plastic.
• an air gap 19 is also provided between the stator 3 and the housing 12.
• the air flowing through this air gap reaches the politiciansableitele element 14 directly so that the heat can be dissipated therefrom.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Mechanical Engineering (AREA)
• Motor Or Generator Cooling System (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70480260

Family Applications (1)

Country Status (5)

Family Cites Families (23)

• 2019
  • 2019-05-03 DE DE102019111472.1A patent/DE102019111472B3/de active Active
• 2020
  • 2020-04-28 US US17/604,877 patent/US12068671B2/en active Active
  • 2020-04-28 CN CN202080030778.0A patent/CN113728533B/zh active Active
  • 2020-04-28 EP EP20723070.7A patent/EP3931950A1/de active Pending
  • 2020-04-28 WO PCT/EP2020/061740 patent/WO2020225028A1/de unknown

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