Handpiece for a micromotor system, and micromotor system for machining a workpiece

Abstract

The invention relates to a handpiece (3) for a micromotor system for machining a workpiece, which handpiece comprises an electric drive motor (45) for rotatingly driving a tool holder (31) about an axis of rotation (36), which electric drive motor is arranged in a housing (21). A fan (62) which is connected to a drive shaft (52) of the electric drive motor (45) is arranged between the electric drive motor (45) and a housing end (28) remote from the tool holder (31). The fan (62) generates an air flow (L) in a flow direction (S) from the fan (62) to the electric drive motor (45).

Description

[0001] Handpiece for a micromotor system and micromotor system for machining a workpiece

[0002] The invention relates to a handpiece for a micromotor system for machining a workpiece. Furthermore, the invention relates to a micromotor system for machining a workpiece.

[0003] Known micromotor systems are used, for example, to perform grinding, milling, polishing, or deburring work. These known micromotor systems each comprise a control unit and a handpiece, which are connected to each other by a cable for power supply and / or to transmit control signals. The handpiece has a compact design and is manually guided by an operator to process the workpiece. To perform various processing tasks, the handpiece can be equipped with different processing tools, for example, grinding, milling, polishing, or cutting tools. Known micromotor systems enable continuous adjustment of the speed of the processing tool over a wide speed range, for example, between 100 rpm and 80,000 rpm.

[0004] The invention is based on the object of creating a handpiece for a micromotor system that enables precise, flexible, reliable and user-friendly machining of a workpiece.

[0005] This object is achieved by a handpiece having the features of claim 1. The fan is arranged between the electric drive motor and the second housing end and is connected to the drive shaft of the electric drive motor. The second housing end is arranged along the axis of rotation opposite the first housing end and faces away from the tool holder. The fan serves to generate an air flow in a flow direction that runs from the fan to the electric drive motor. For this purpose, the fan is designed such that when the electric drive motor is operated in a desired direction of rotation, the air flow is generated in the flow direction. The air flow is thus directed from the second housing end to the electric drive motor and to the first housing end or the tool holder arranged on the first housing. The fan is designed in particular such that the air flow is accelerated and compressed.The fan is particularly designed such that the following applies to a pressure ratio p / pi: 1.5 < p / pi < 10, in particular 2 < p / pi < 7, and in particular 2.5 < p / pi < 4. The pressure pi denotes the absolute pressure upstream of the fan, whereas the pressure p denotes the absolute pressure downstream of the fan. The fan is particularly designed as a compressor. A pressure ratio p / pi > 1.5 preferably applies to the compressor.

[0006] The fan comprises, in particular, a compressor section for generating the air flow and increasing the air pressure in the flow direction. The compressor section has a length Lv along the axis of rotation and a maximum diameter Dv radially to the axis of rotation, wherein the following applies in particular: 0.6 < Lv / Dv < 3, in particular 0.8 < Lv / Dv < 2.5 and in particular 1 < Lv / Dv < 2. Preferably, the compressor section comprises a conical compressor base body, on which a plurality of compressor blades are arranged on the circumference. Preferably, the compressor base body is conical in an axial section, at least in sections. A diameter of the compressor base body increases in the flow direction. Preferably, the compressor base body has a minimum diameter Dmin and a maximum diameter Dmax, wherein the following applies in particular to a ratio Dmax / Dmin: 2 < Dmax / Dmin < 10, in particular 2.5 < < 8, and in particular 3 < Dmax / Dmin < 6. As a result, in particular, a free cross-sectional area or a gap between the fan and an air guide component tapers in the flow direction, so that the air is compressed in the flow direction. Preferably, the air guide component and a compressor section of the fan form a maximum free cross-sectional area Amax and a minimum free cross-sectional area Amin in a cross-section perpendicular to the axis of rotation, where in particular: 2 < Amax / Amin < 10, in particular 3 < Amax / Amin < 9, and in particular 4 < Amax / Amin < 8.

[0007] The fan preferably comprises a fastening section for attachment to the drive shaft. The fastening section is, in particular, formed integrally with the compressor section. The fastening section is circular-cylindrical and extends, in particular, into a through-opening of a partition wall of the air guide component.

[0008] The fan is attached directly to the drive shaft. This connection of the fan to the drive shaft results in a compact design. The airflow generated by the fan flows directly around the electric drive motor, ensuring efficient cooling. This enables reliable operation of the electric drive motor even at high drive power levels. The compact arrangement of the fan on the drive shaft saves weight and reduces vibrations in the handpiece. The direction of the airflow removes dust created during machining of the workpiece from the handpiece. This increases reliability and user-friendliness, as dust does not get into the handpiece and reach the operator. The handpiece thus enables precise, flexible, and user-friendly machining of a workpiece.

[0009] At least one air inlet opening is formed in the housing between the fan and the second housing end. Preferably, a plurality of air inlet openings are formed circumferentially at the second housing end. In particular, at least one air outlet opening is formed between the electric drive motor and the first housing end. Preferably, the at least one air outlet opening is arranged at the first housing end. In the housing, a plurality of air outlet openings are formed, in particular at the front end of the first housing end. The air outlet openings preferably surround the tool holder in a ring shape. Because the air flow exits the air outlet openings, dust generated during the machining of a workpiece is blown away from the handpiece and thus not sucked into the housing of the handpiece.Preferably, the handpiece has at least one filter element which is arranged at the at least one air inlet opening and / or at the at least one air outlet opening.

[0010] The handpiece, in particular the housing, is designed to be guided manually with just one hand. The housing is preferably hollow-cylindrical, in particular circular in cross-section. The housing can be grasped in particular with a single hand. The handpiece has a mass mH, where in particular the following applies: 500 g < mH < 1,400 g, in particular 700 g < mH < 1,200 g, and in particular 800 g < mH < 1,100 g. The housing comprises in particular a hollow-cylindrical housing shell and housing caps arranged at the ends. The housing shell can be formed in one piece or in several parts. The housing shell is in particular made of a metal, preferably steel. The housing has a maximum outer diameter DG. The following applies in particular to the maximum outer diameter DG: 1 cm < DG < 7 cm, in particular 2 cm < DG < 6 cm, and in particular 3 cm < DG < 5 cm.

[0011] The electric drive motor is designed, in particular, as a brushless direct current motor (BLDC motor). The electric drive motor has a maximum speed nmax, where, in particular, the following applies: 10,000 rpm L Umax L 80,000 rpm, in particular 20,000 rpm < nmax < 60,000 rpm, and in particular 25,000 rpm < nmax < 40,000 rpm. The electric drive motor has a rated power PN, where, in particular, the following applies: 100 W < PN < 1,600 W, in particular 200 W < PN < 1,400 W, and in particular 300 W < PN < 1,000 W.

[0012] The handpiece preferably comprises an actuating element for actuating, in particular for switching on and off, the electric drive motor. The actuating element is arranged at least partially outside the housing. The actuating element is designed, for example, as a spring-loaded switching pin. The actuating element is preferably part of an actuating unit that is arranged at least partially within the housing.

[0013] A handpiece according to claim 2 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The air guide component is arranged along the rotational axis between the electric drive motor and the second housing end within the housing. The air guide component is thus arranged upstream of the electric drive motor in the flow direction. The air guide component is in particular formed as a single piece, for example from a plastic material. The air guide component serves, on the one hand, to support and center the electric drive motor on the fan side within the housing. On the other hand, the air guide component serves to guide the air flow in the housing such that the electric drive motor is efficiently surrounded and cooled by the air flow.

[0014] A handpiece according to claim 3 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The air guide component forms, at least in some regions, a cylindrical outer wall that rests against an inner wall of the housing. As a result, the air guide component is centered in the housing and fixed in a radial direction to the axis of rotation. On a side facing the electric drive motor, the air guide component forms a bearing for supporting the electric drive motor. The bearing is arranged on the fan side from the perspective of the electric drive motor. The fan-side bearing is designed, for example, in the form of a recess in the air guide component, in which an end of the electric drive motor facing the second housing end is received or mounted. The electric drive motor is thus centered in the fan-side bearing relative to the housing and fixed in the radial direction.

[0015] A handpiece according to claim 4 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The air guiding component comprises, in particular, a partition wall which separates the receiving space, at least in part, from a fan-side bearing for supporting the electric drive motor. A through-opening is formed in the partition wall, into which the drive shaft and / or the fan extend, at least in part. Because the fan is arranged, at least in part, in the receiving space, the air flow is guided in the gap between the air guiding component and the fan. This allows the guidance of the air flow to be specifically influenced. The partition wall prevents, in particular, the air flow from striking the front of the electric drive motor, thereby slowing it down and reducing the air throughput.

[0016] A handpiece according to claim 5 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The at least one deflection channel runs from the receiving space at an angle to the axis of rotation in the direction of an inner wall of the housing. The at least one deflection channel connects, in particular, the receiving space to an annular gap formed between the electric drive motor and the housing. The at least one deflection channel guides the air flow from the receiving space into the annular gap, so that the electric drive motor flows around its circumference and is efficiently cooled. The following applies to a number N of the at least one deflection channel: 1 < N < 20, in particular 2 < N < 16, and in particular 3 < N < 12. Several deflection channels extend from the receiving space to the annular gap, distributed around the axis of rotation.

[0017] A handpiece according to claim 6 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The electric drive motor is preferably mounted on the housing via a fan-side bearing and a tool-holder-side bearing. The electric drive motor is preferably mounted on the housing in such a way that the electric drive motor is freely suspended between the bearings in the region of its stator in the housing. The fan-side bearing is formed, for example, by the air-guiding component. The tool-holder-side bearing is formed, for example, by an annular bearing component that is fastened to an inner wall of the housing. In particular, the electric drive motor is mounted on the housing exclusively via the air-guiding component and the bearing component, so that the electric drive motor is freely suspended in the region of its stator in the housing.The annular gap between the electric drive motor and the housing extends, in particular, along the rotational axis and along the circumference, entirely within the stator region. This increases and optimizes the available free surface area for cooling the electric drive motor. The at least one deflection channel, preferably the plurality of deflection channels, open into the annular gap at an angle relative to the rotational axis, creating low flow resistance for the airflow and directing and distributing the airflow into the annular gap. This enables efficient cooling of the electric drive motor.

[0018] A handpiece according to claim 7 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The at least one line guide is arranged in particular outside a receiving space of the air guide component, in which the fan is arranged at least in part, so that the power supply line and / or the signal line is protected from the fan rotating during operation. The at least one line guide carries at least one power supply line and / or at least one signal line, in particular between the air guide component and the housing. The at least one line guide is designed, for example, like a groove. Preferably, the at least one line guide is designed to secure, in particular to clamp, the at least one power supply line and / or the at least one signal line.Preferably, the air guide component forms a plurality of line guides for guiding and securing all power supply lines and / or signal lines required for the operation of the electric drive motor.

[0019] A handpiece according to claim 8 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The support element fixes the air guide component along the rotational axis, so that the air guide component is fixed both in an axial direction and in a radial direction by resting against the housing. The support element is particularly elastic. The support element is formed, for example, from a plastic material. The support element is particularly annular, for example as a clamping ring or snap ring. The support element is arranged within the housing and, in particular, fastened to the housing. For example, the support element is fastened in an annular groove on the inner wall of the housing.

[0020] A handpiece according to claim 9 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The funnel component has a through-opening whose diameter decreases in the direction of flow. This creates a suction effect on the air, which improves the air supply to the fan. The funnel component is arranged within the housing and bears against the housing, in particular in a radial direction. Preferably, the funnel component bears against a vibration-damping support element, wherein the funnel component is arranged upstream of the vibration-damping support element in the direction of flow. The funnel component preferably comprises at least one line guide for guiding at least one power supply line and / or at least one signal line to the electric drive motor.The at least one cable guide is arranged in a radial direction between the through opening and the housing.

[0021] A handpiece according to claim 10 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The bearing shield is arranged on a side of the electric drive motor facing the first housing end. The bearing shield is connected in particular to a motor housing of the electric drive motor. The bearing shield is mounted in particular on an annular bearing component of the handpiece. The annular bearing component forms a tool holder-side bearing for the bearing shield. Because the electric drive motor is mounted and centered on the housing by means of the bearing shield, the electric drive motor is arranged freely suspended in the housing in the region of the stator. Preferably, the electric drive motor is mounted on the side opposite the bearing shield in a fan-side bearing of an air guide component.As a result, the electric drive motor is mounted at two bearing points at a maximum distance along the axis of rotation, so that the electric drive motor is precisely centered. The annular bearing component is preferably fastened to an inner wall of the housing. The bearing component is in particular formed integrally with the housing. The bearing component preferably comprises a bearing opening for receiving and supporting the bearing shield. Furthermore, the bearing component in particular comprises through-flow openings for the air flow. The through-flow openings are arranged distributed around the bearing opening. The through-flow openings open in particular into the annular gap between the electric drive motor and the housing. Preferably, the bearing shield is secured to the bearing component in the direction of the axis of rotation by a securing element. The securing element and the bearing shield can, for example, form a detachable connection with one another, in particular a threaded connection.Preferably, the locking element and the bearing plate are screwed together.

[0022] A handpiece according to claim 11 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The tubular multifunctional component is arranged within the housing. The multifunctional component is arranged upstream of the fan in the flow direction, in particular upstream of an air guiding component and / or a funnel component. The multifunctional component serves for mounting, for example, an actuating unit for actuating the electric drive motor and / or a connection socket for connecting at least one power supply line and / or at least one signal line. The multifunctional component also serves to guide the air flow in the flow direction. Furthermore, the multifunctional component can serve to guide at least one power supply line and / or at least one signal line, preferably to the electric drive motor and / or to the actuating unit.The multifunctional component is preferably constructed as a single piece. The multifunctional component is preferably made of a plastic material. The multifunctional component is optimized in terms of dimensions and weight, making the handpiece compact and user-friendly.

[0023] The multifunctional component preferably comprises an interior space and at least one through-flow opening leading into the interior space. The multifunctional component in particular comprises a plurality of through-flow openings. This allows the air flow from at least one air inlet opening formed in the housing to be guided into the interior space of the multifunctional component. In the interior space, the air flow can in particular cool the actuating unit and continue to flow in the flow direction to the fan and the electric drive motor. The multifunctional component preferably comprises an actuating opening through which an actuating element extends into the interior space. The actuating opening is arranged downstream of the at least one through-flow opening in the flow direction.

[0024] A handpiece according to claim 12 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The connection socket is arranged, in particular, at the second housing end and is accessible from outside the housing for connecting at least one power supply line and / or at least one signal line. Preferably, the connection socket is connected, in particular detachably connected, to a tubular multifunctional component. For example, the connection socket is screwed to the multifunctional component via a threaded connection. At least one power supply line and / or at least one signal line runs from the connection socket to the electric drive motor and / or to an actuating unit for actuating the electric drive motor.The multifunctional component comprises in particular at least one through-flow opening for guiding air into an interior of the multifunctional component, wherein the at least one through-flow opening is preferably arranged downstream of the connection socket in the flow direction.

[0025] A handpiece according to claim 13 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The actuating unit comprises, in particular, an actuating element, a switch, and / or a circuit board. The switch is preferably arranged on the circuit board. The circuit board with the switch arranged thereon is preferably arranged in an interior space of a multifunctional component. The circuit board is fastened, for example screwed, to the multifunctional component in the interior space. As a result, the circuit board is cooled in the air stream flowing through the multifunctional component. The switch is securely fastened, so that the handpiece is highly reliable. The actuating element extends through a housing opening into the housing and through an actuating opening formed in the multifunctional component into the interior space to the switch. As a result, the switch can be actuated by means of the actuating element.The actuating element is designed, for example, as a switching pin preloaded by a spring.

[0026] The handpiece preferably comprises a data memory for storing data and / or information, in particular a unique handpiece identification and / or control parameters and / or regulating parameters and / or runtimes and / or error codes. The data memory is in particular semi-permanent and / or permanent. The data memory is preferably electronic, for example, as a chip. The data memory is preferably arranged on the circuit board.

[0027] In particular, a handpiece-side receiver for receiving data and / or signals from a control unit and / or a handpiece-side transmitter for transmitting data and / or signals to a control unit are arranged in the housing. The receiver and / or the transmitter are arranged in particular on the circuit board. Preferably, a receiver and a transmitter are arranged in the housing to implement bidirectional transmission of data and / or signals.

[0028] The invention is further based on the object of creating a micromotor system that enables precise, flexible, reliable and user-friendly machining of a workpiece.

[0029] This object is achieved by a micromotor system having the features of claim 14. The advantages of the micromotor system correspond in particular to the already described advantages of the handpiece. The micromotor system can be further developed, in particular, with at least one feature described in connection with the handpiece according to the invention.

[0030] The control unit is, in particular, designed separately from the handpiece. The control unit comprises a control unit for controlling and / or regulating an electric drive motor of the handpiece. The control unit comprises, in particular, the motor control of the electric drive motor. The electric drive motor is, in particular, designed as a brushless direct current motor (BLDC motor). The control unit comprises a control unit housing in which the control unit is arranged. Furthermore, the control unit comprises at least one operating element for operating the control unit or the micromotor system. The at least one operating element is arranged on the control unit housing.

[0031] The micromotor system comprises, in particular, a power supply device. The power supply device comprises, in particular, a power supply unit and / or at least one rechargeable battery and / or at least one connection for a power supply unit and / or for a rechargeable battery. The power supply unit is arranged, for example, in the control unit and / or on the control unit. The at least one rechargeable battery is arranged in the handpiece and / or in the control unit and / or on the control unit. The at least one rechargeable battery is preferably replaceable. The power supply device preferably comprises a cable for power transmission, in particular for connection to the control unit and to the handpiece. For this purpose, the control unit and the handpiece each comprise, for example, a connection socket.The cable comprises in particular at least one power supply line, preferably several power supply lines, for providing electrical energy for the operation of the electric drive motor.

[0032] The micromotor system comprises a transmission device for transmitting data and / or signals between the control unit and the handpiece. The transmission device is designed, in particular, for wired and / or wireless transmission of data and / or signals. The transmission device preferably comprises a cable for signal transmission. The cable is, in particular, combined with a power supply cable to form a common cable. The signal transmission cable, in particular, comprises at least one signal transmission line for transmitting data and / or signals between the control unit and the handpiece. The micromotor system, in particular, comprises a cable with at least one power supply line and at least one signal transmission line.

[0033] The transmission device comprises, in particular, at least one transmitter and at least one receiver. For transmitting data and / or signals from the control unit to the handpiece, a control unit-side transmitter is preferably arranged in the control unit, and a handpiece-side receiver is arranged in the handpiece.

[0034] The handpiece preferably comprises a data memory for storing data and / or information, in particular a unique handpiece identification and / or control parameters and / or regulating parameters and / or runtimes and / or error codes. The data memory is in particular semi-permanent and / or permanent. The data memory is preferably electronic, for example, as a chip. The data memory is in particular arranged within a housing of the handpiece, for example on a circuit board.

[0035] The data memory serves to store data and / or information transmitted from the control unit to the handpiece, and / or to store data and / or information transmitted from the handpiece to the control unit. In particular, the data memory serves to store a handpiece identification. The handpiece identification serves to uniquely identify the handpiece. Preferably, the data memory serves to store control parameters and / or regulation parameters and / or error codes and / or operating parameters, such as running times, speeds, processing times, and contact pressures.

[0036] A micromotor system according to claim 15 ensures precise, flexible, reliable, and user-friendly machining of a workpiece. The transmission device comprises a control unit-side transmitter and a control unit-side receiver, as well as a handpiece-side transmitter and a handpiece-side receiver, for the bidirectional transmission of data and / or signals. The control unit-side transmitter and the control unit-side receiver are arranged, in particular, in the control unit. The handpiece-side transmitter and the handpiece-side receiver are arranged, in particular, in the handpiece or in a housing of the handpiece. The handpiece comprises, in particular, a circuit board on which the handpiece-side transmitter and the handpiece-side receiver are arranged.The handpiece-side transmitter and / or the handpiece-side receiver is in particular designed to be passive and provides an interface for reading out data and / or signals and / or for storing data and / or signals.

[0037] Further features, advantages, and details of the invention will become apparent from the following description of an exemplary embodiment. It shows:

[0038] Fig. 1 is a schematic view of a micromotor system with a control unit and a handpiece,

[0039] Fig. 2 is a sectional view through the handpiece in Fig. 1, Fig. 3 is an enlarged sectional view III of the handpiece in Fig. 2 in the area of ​​a multifunctional component,

[0040] Fig. 4 is an enlarged sectional view IV of the handpiece in Fig. 2 in the area of ​​an air guide component and an electric drive motor,

[0041] Fig. 5 is an enlarged sectional view V of the handpiece in Fig. 2 in the area of ​​a bearing plate of the electric drive motor,

[0042] Fig. 6 is a perspective view of the multifunctional component, and

[0043] Fig. 7 is a perspective view of the air guide component.

[0044] The micromotor system 1 illustrated in Fig. 1 is used for machining a workpiece (not shown in detail), for example, for performing grinding, milling, polishing, and / or for cutting or deburring the workpiece. The micromotor system 1 comprises a control unit 2, a handpiece 3, a power supply unit 4, and a transmission unit 5.

[0045] The control unit 2 comprises a control unit housing 6, a control unit 7, a display 8, and operating elements 9. The control unit 7 is arranged in the control unit housing 6 and serves to control the micromotor system 1, in particular to control and / or regulate the handpiece 3. The display 8 and the operating elements 9 are arranged on the control unit housing 6 and enable operation of the micromotor system 1 by an operator. The energy supply device 4 comprises a power supply 10 and / or a rechargeable battery 10'. The control unit housing 6 forms a receiving space 11 for optionally receiving the power supply 10 or the rechargeable battery 10'. In Fig. 1, for example, the power supply 10 is arranged in the receiving space 11. The power supply 10 is connected to the control unit 2 in the receiving space 11 by means of a supply interface (not shown in detail).Alternatively, the accumulator 10' can be connected to the control unit 2 via the supply interface. The power supply 10 can be connected to a public power grid via a power cable 12. The power supply 10 includes a rectifier for generating a direct voltage from the alternating voltage applied via the power cable 12. The accumulator 10' enables operation of the micromotor system 1 without a power supply via the power cable 12 or the power supply 10.

[0046] The power supply device 4 further comprises a plurality of power supply lines 13 for transmitting power from the power supply unit 10 or the accumulator 10' or from the control unit 2 and the control unit 7 to the handpiece 3. For this purpose, a cable 14 is connected to the control unit 2 and the handpiece 3. The power supply lines 13 run in the cable 14.

[0047] The transmission device 5 is designed for the bidirectional transmission of data and / or signals between the control unit 2 and the handpiece 3. For this purpose, the transmission device 5 comprises a control unit-side transmitter 15 and a control unit-side receiver 16, as well as a handpiece-side transmitter 17 and a handpiece-side receiver 18. The control unit-side transmitter 15 and the control unit-side receiver 16 are arranged in the control unit housing 6. The control unit-side transmitter 15 and the control unit-side receiver 16 are, in particular, integrated. The handpiece-side transmitter 17 and the handpiece-side receiver 18 are arranged in the handpiece 3. The handpiece-side transmitter 17 and the handpiece-side receiver 18 are, in particular, integrated. The transmission device 5 is wired and comprises signal lines 19.The signal lines 19 connect the control unit-side transmitter 15 to the handpiece-side receiver 18, and the handpiece-side transmitter 17 to the control unit-side receiver 16 for bidirectional transmission of data and / or signals. The signal lines 19 are arranged in the cable 14.

[0048] For storing data and / or information, the handpiece 3 includes an electronic data storage device 20. The data storage device 20 is semi-permanent and / or permanent. The data storage device 20 is in signal communication with the handpiece-side transmitter 17 and the handpiece-side receiver 18, so that data and / or information can be transmitted from the control unit 2 to the handpiece 3 and stored on the data storage device 20, and data and / or information stored on the data storage device 20 can be transmitted to the control unit 2. The data storage device 20 is designed, for example, as a chip.

[0049] The handpiece 3 comprises a housing 21 which delimits a housing interior 22. The housing 3 comprises a housing shell 23, a grip sleeve 24, a first housing cap 25 and a second housing cap 26. The housing shell 23 is made, for example, from metal, in particular from steel. The housing shell 23 is hollow-cylindrical and has a circular cross-section. The grip sleeve 24 surrounds the housing shell 23 and is fastened thereto. The grip sleeve 24 is made, for example, from a plastic material. The first housing cap 25 is fastened to the housing shell 23 on a first side and defines a first housing end 27. In contrast, the second housing cap 26 is fastened to a second side of the housing shell 23 and defines a second housing end 28. The housing 21 has a maximum outer diameter DG.The maximum outer diameter DG is designed such that an operator can grasp and manually guide the handpiece 3 with just one hand. The following applies in particular to the maximum outer diameter DG: 1 cm < DG < 7 cm, in particular 2 cm < DG < 6 cm, and in particular 3 cm < DG < 5 cm.

[0050] To generate an air flow L in the housing interior 22 in a flow direction S, the second housing cap 26 has a plurality of air inlet openings 29. The air inlet openings 29 are distributed circumferentially on the second housing cap 26. The first housing cap 25 has a plurality of air outlet openings 30. The air outlet openings 30 are distributed along the end faces of the first housing cap 25. The flow direction S thus runs from the second housing end 28 to the first housing end 27.

[0051] The handpiece 3 comprises a tool holder 31 for the replaceable attachment of a machining tool 32. The tool holder 31 is arranged at the first housing end 25. For this purpose, the first housing cap 25 has a housing cap opening 33 through which the tool holder 31 is guided into the housing interior 22. In the housing interior 22, the tool holder 31 is rotatably mounted about a rotation axis 36 by means of a first bearing 34 and a second bearing 35. The bearings 34, 35 are spaced apart along the rotation axis 36. The tool holder 31 and the bearings 34, 35 form a spindle for rotating the machining tool 32 about the rotation axis 36.

[0052] The bearings 34, 35 are supported on the tool holder 31 and on a bearing sleeve 37. The second bearing 35 is mounted on the bearing sleeve 37 via vibration-damping rubber elements. The bearing sleeve 37 is mounted in the housing 21 such that a first annular gap 38 is formed between the bearing sleeve 37 and an inner wall of the housing 21. For this purpose, the bearing sleeve 37 is mounted on a first annular bearing component 39 and, via a securing element 40, on a second annular bearing component 41. The first bearing component 39 is fastened to the housing shell 23. The first bearing component 39 comprises a plurality of first flow openings 42 distributed around the rotation axis 36, which essentially overlap with the air outlet openings 30. A first filter element 43 is arranged between the first flow openings and the air outlet openings 30.

[0053] The bearing sleeve 37 is further fastened to the securing element 40, which in turn is mounted on the second bearing component 41. The second bearing component 41 comprises a plurality of second flow openings 44, which are distributed around the rotational axis 36 and open into the first annular gap 38. The second bearing component 41 is fastened to an inner wall of the housing 21. The second bearing component 41 is, in particular, formed integrally with the housing shell 23.

[0054] To drive the tool holder 31 in rotation about the rotation axis 36, the handpiece 3 comprises an electric drive motor 45. The electric drive motor 45 is arranged in the housing interior 22. The electric drive motor 45 is designed as a brushless direct current (BLDC) motor. The control unit 7 comprises the motor controller or the motor electronics for controlling and / or regulating the electric drive motor 45.

[0055] The electric drive motor 45 is encapsulated. The electric drive motor 45 comprises a hollow cylindrical motor housing 46, a bearing plate 47, and a bearing cover 48. The bearing plate 47 is attached to the motor housing 46 on a side facing the first housing end 27, whereas the bearing cover 48 is attached to the motor housing 46 on a side facing the second housing end 28.

[0056] The bearing plate 47 is guided with a hollow cylindrical bearing section through a bearing opening of the second bearing component 41 and mounted on the second bearing component 41. The bearing section is screwed to the securing element 40 via a threaded connection 49. This centers the electric drive motor 45 with the rotatably mounted tool holder 31 and fixes it radially to the rotational axis 36 and along the rotational axis 36 in the housing 21. The second bearing component 41 forms a tool holder-side bearing for the electric drive motor 45.

[0057] The electric drive motor 45 further comprises a stator 50, a rotor 51, and a drive shaft 52. The stator 50 and the rotor 51 are shown only schematically in Figures 2 to 5. The stator 50 is fastened to the motor housing 46. The rotor 51 is fastened to the drive shaft 52 and, together with the drive shaft 52, is arranged within the stator 50. The drive shaft 52 extends through a first through-opening 53 in the bearing plate 47 and is connected to the tool holder 31. The drive shaft 52 is rotatably mounted in the first through-opening 53 by means of a shaft bearing 54.

[0058] The bearing cover 48 is mounted on an air guide component 55. The air guide component 55 is partially hollow-cylindrical in shape and rests with an outer wall against the inner wall of the housing 21. This centers the air guide component 55 relative to the rotation axis 36. The air guide component 55 comprises a partition 56 running perpendicular to the rotation axis 36, which has a through-opening 57 concentric with the rotation axis 36. The air guide component 55 forms a fan-side bearing 58 in the form of a recess and a receiving space 59, which are delimited by the partition 56. The recess faces the electric drive motor 45 and is shaped accordingly to the bearing cover 48. The bearing cover 48 is arranged in the recess or the fan-side bearing 58 so that the electric drive motor 45 is centered relative to the rotation axis 36 and fixed radially to the rotation axis 36.The bearing cover 48 has a second through-opening 60 through which the drive shaft 52 is guided. The drive shaft 52 is mounted on the bearing cover 48 by means of a second shaft bearing 61.

[0059] The handpiece 3 comprises a fan 62 arranged within the housing 21. The fan 62 is arranged between the electric drive motor 45 and the second housing end 28. The fan 62 is arranged in the receiving space 59 of the air guide component 55 and is fastened directly to the drive shaft 52. The fan 62 serves to generate the air flow L in the flow direction S. The fan 62 is arranged upstream of the electric drive motor 45 in the flow direction S and is designed such that when the electric drive motor 45 is operated in a desired direction of rotation D, the air flow L is generated in the flow direction S, i.e. is pushed by the fan 62 to the electric drive motor 45.

[0060] The fan 62 comprises a mounting portion 63 and a compressor portion 64. The mounting portion 63 is cylindrical and extends into the through-opening 57. The drive shaft 52 also extends into the through-opening 57 and is connected to the mounting portion 64.

[0061] The air guide component 55 serves, on the one hand, to mount the electric drive motor 45 as mentioned above and, on the other hand, to guide the air flow L within the housing 21. For this purpose, the air guide component 55 comprises a plurality of deflection channels 65 that run obliquely to the axis of rotation 36 and connect the receiving space 59 to a second annular gap 66. The second annular gap 66 is arranged between the motor housing 46 and the inner wall of the housing 21. Due to the mounting of the electric drive motor 45 by means of the bearing plate 47 on the one hand and by means of the bearing cover 48 on the other hand, the motor housing 46 or the electric drive motor 45 is exposed within the housing 21 in the region of the stator 50. As a result, the motor housing 46 forms a completely free surface in the region of the stator 50, which can be flowed around and cooled by the air flow L in the second annular gap 66.

[0062] The handpiece 3 comprises a support element 67 against which the air guide component 55 rests. The support element 67 is annular and secured in an annular groove 68 formed on the inner wall of the housing 21. The support element 67 is thus arranged upstream of the air guide component 55 in the flow direction S and between the air guide component 55 and the second housing end 28. The support element 67 is designed, for example, as a snap ring.

[0063] The fan 62 is formed in one piece. Preferably, the fan 62 is made of a plastic material. The fan 62 comprises a compressor base body 69 and compressor blades 70 arranged thereon. The compressor base body 69 and the compressor blades 70 form the compressor section 64. The compressor base body 69 is conical or, in axial section through the rotation axis 36, conical. The compressor base body 69 widens in the flow direction S. The compressor section 64 has a maximum diameter Dv radially to the rotation axis 36 and a maximum length Lv along the rotation axis 36. The following applies in particular to a ratio Lv / Dv: 0.6 < Lv / Dv < 3, in particular 0.8 < Lv / Dv < 2.5 and in particular 1 < Lv / Dv < 2.The compressor base body 69 has a maximum diameter Dmax and a minimum diameter Dnün, wherein the following applies in particular to a ratio Dmax / Dmin: 2 < Dmax / Dmin < 10, in particular 2.5 < Dmax / Dmin < 8, and in particular 3 < Dmax / Dmin < 6. The air guide component 55 and the compressor section 64 of the fan 62 delimit between them, in a cross-section perpendicular to the rotation axis 36, a maximum free cross-sectional area Amax and a minimum free cross-sectional area Amin. The following applies in particular to a ratio Amax / Amin: 2 < Amax / Amin < 10, in particular 3 < Amax / Amin < 9, and in particular 4 < Amax / Amin < 8.

[0064] The handpiece 3 further comprises a funnel component 71, which is arranged in front of the support element 67 within the housing 21 in the flow direction S and bears against the support element 67. The funnel component 71 has a funnel-shaped flow opening 72. The funnel-shaped flow opening 72 has a diameter DT that decreases in the flow direction S. The funnel component 71 creates a suction effect on the air flow L.

[0065] The air guide component 55 also serves to guide the power supply lines 13 to the electric drive motor 45. For this purpose, the air guide component 55 comprises a channel-like or groove-like line guide 73. The line guide 73 is arranged on an outer side of the air guide component 55 and extends outside the receiving space 59 from the funnel component 71 to the electric drive motor 45. This prevents damage to the power supply lines 13 by the fan 62. Accordingly, the funnel component 71 has a line guide 74 that runs on an outer side and outside the flow opening 72. The second line guide 74 is substantially aligned with the first line guide 73.

[0066] The handpiece 3 further comprises a multifunctional component 75, a connection socket 76, and an actuating unit 77. The actuating unit 77 serves to actuate the electric drive motor 45. The multifunctional component 75 is shown in Fig. 6. The multifunctional component 75 serves for air guidance and mounting. The multifunctional component 75 is arranged between the fan 62 or the air guidance component 55 and the second housing end 28 within the housing 21. The multifunctional component 75 rests against the funnel component 71 and is screwed to the connection socket 76 at the second housing end 28 via a threaded connection 78. For this purpose, the multifunctional component 75 has an internal thread that interacts with an external thread on the connection socket 76. The connection socket 76 is fixed along the rotation axis 36 by means of the second housing cap 26.The connection socket 76 comprises several connection pins 79 for connecting the power supply lines 13 and the signal lines 19.

[0067] The multifunctional component 75 is tubular. Due to its tubular design, the multifunctional component 75 partially defines an interior space 80. The multifunctional component 75 is formed as a single piece. The multifunctional component 75 is preferably made of a plastic material.

[0068] On a side of the multifunctional component 75 facing the first housing end 27, a circuit board 81 with a switch 82 arranged thereon is arranged in the interior 80 and fastened to the multifunctional component 75. The switch 82 interacts with an actuating element 83 in the form of a spring-loaded switching pin. The switching pin is fastened to the housing 21 and extends through a housing opening 84 of the housing 21 and an actuating opening 85 of the multifunctional component 75 into the interior 80 to the switch 82. The circuit board 81, the switch 82, the actuating element 83, and an actuating lever 86 are part of the actuating unit 77. The actuating lever 86 serves to actuate the switching pin and is pivotably attached to the housing 21.

[0069] To guide air from the air inlet openings 29 into the interior 80, the multifunctional component 75 comprises a plurality of flow openings 87, which are distributed around the rotation axis 36. The flow openings 87 are arranged in front of the actuating opening 85 in the flow direction S. A second filter element 89 is held in the second housing cap 26 and is thus arranged between the air inlet openings 29 and the flow openings 87. In the interior 80, the air flow L is directed toward the funnel component 71 and flows past the circuit board 81 and the switch 82.

[0070] On an outer side, the multifunctional component 75 forms a third cable guide 88. Power supply lines 13 run from the electric drive motor 45 through the cable guides 73, 74, and 88 and are connected to the corresponding connection pins 79 in the connection socket 76. The power supply lines 13 within the housing 21 are only partially shown.

[0071] The handpiece-side transmitter 17, the handpiece-side receiver 18, and the data memory 20 are arranged on the circuit board 81. These are integrated, for example, in a single chip. The data memory 20 is signal-connected to the handpiece-side transmitter 17 and the handpiece-side receiver 18. The handpiece-side transmitter 17 and the handpiece-side receiver 18 are connected to corresponding connector pins 79 via signal lines (not shown in detail).

[0072] The functionality of the micromotor system 1 is described in detail below:

[0073] To operate the micromotor system 1, the control unit 2 is connected to the public power grid via the power cable 12, and the cable 14 is connected to a connection socket on the control unit 2 and to the connection socket 76 on the handpiece 3. After the control unit 2 is switched on using a control element 9, the micromotor system 1 is ready for operation. A unique handpiece identification and handpiece-specific control parameters are stored on the data storage device 20, which are initially transmitted to the control unit 7 via the handpiece-side transmitter 17 and the control unit-side receiver 16. This enables handpiece-specific control and / or regulation of the handpiece 3.

[0074] When the switch 82 is actuated, the control unit 7 controls the electric drive motor 45 via the actuating lever 86 and the actuating element 83. The electric drive motor 45 is operated, for example, with speed control. For this purpose, electrical energy is transmitted to the electric drive motor 45 via the power supply lines 13.

[0075] When the actuation unit 77 is actuated, the electric drive motor 45 rotates in the desired direction of rotation D around the rotation axis 36. An operator manually guiding the handpiece 3 can now machine a workpiece in the desired manner using a machining tool 32 clamped in the workpiece holder 31. Due to the rotating drive shaft 52, the fan 62 also rotates in the desired direction of rotation D. This generates the air flow L, which flows from the air inlet openings 29 in the flow direction S through the housing interior 22 to the air outlet openings 30.

[0076] In detail, the fan 62 draws in air through the air inlet openings 29. The generated air flow L initially flows from the air inlet openings 29 through the second filter element 89 and further between the housing 21 and the multifunctional component 75 to the flow openings 87 and through these into the interior space 80. In the interior space 80, the air flow L flows past the circuit board 81 essentially parallel to the rotation axis 36, thereby cooling the handpiece-side transmitter 17, the handpiece-side receiver 18, the data storage device 20, the circuit board 81, and the switch 82.

[0077] The funnel component 71 creates a suction effect which accelerates the air flow L towards the fan 62. The fan 62 acts as a compressor and presses the air from the gap between the compressor section 64 and the air guide component 55 into the deflection channels 65 and from there into the second annular gap 66. The fan 62 is designed such that the following applies to a pressure ratio p / pi in particular: 1.5 < pi / pi < 10, in particular 2 < pi / pi < 7, and in particular 2.5 < p / pi < 4, where pi denotes the absolute pressure of the air flow L upstream of the fan 62 and p the absolute pressure of the air flow L downstream of the fan 62. Because the electric drive motor 45 is arranged freely suspended in the housing 21 between the bearing plate 47 and the bearing cover 48, the electric drive motor 45 is efficiently cooled by the air flow L in the region of the motor housing 46 or the stator 50.After the second annular gap 66, the air flow L initially flows through the second flow openings 44 into the first annular gap 38 and from there through the first flow openings 42 and the first filter element 43 to the air outlet openings 30.

[0078] When the handpiece 3 is switched off, operating times and / or error codes determined by the control unit 7 are transmitted to the data memory 20 and stored there.

[0079] The electric drive motor 45 is stably mounted and centered within the housing 21 by means of the bearing plate 47 and the second bearing component 41 on the one hand, and by means of the bearing cover 48 and the air guide component 55 on the other, so that the electric drive motor 45 is low-vibration during operation. Furthermore, due to its mounting in the area of ​​the motor housing 46, the electric drive motor 45 is exposed, so that the air flow L can flow through the second annular gap 66 and efficiently cool the electric drive motor 45. Because the fan 62 is attached directly to the drive shaft 52 and is arranged upstream of the electric drive motor 45 in the flow direction S, the fan 62, in conjunction with the air guide component 55, can compress the air and force it into the second annular gap 66. This increases the cooling efficiency.In addition, dust generated during the processing of a workpiece is blown away from the handpiece 3 due to the flow direction S and is not sucked into the handpiece 3. The air guide component 55 and the multifunctional component 75 ensure a compact and lightweight design of the handpiece, whereby the micromotor system 1 can be precisely guided manually, is flexible in use, and is user-friendly.

[0080] Because the handpiece 3 includes the data memory 20, the handpiece 3 can be operated individually and therefore extremely flexibly. Because a unique handpiece identification and handpiece-specific control and / or regulation parameters are stored in the data memory 20, each handpiece 3 can be operated with its own control and / or regulation parameters. In particular, this avoids the need to operate several different handpieces with identical control and / or regulation parameters stored in the control unit, as is the case in the prior art. The data memory 20 thus increases the flexibility of the micromotor system 1 according to the invention and expands its range of applications. The transmission device 5 enables the required bidirectional transmission of data and / or signals between the control unit 2 and the respectively connected handpiece 3.

Claims

Patent claims 1. Handpiece for a micromotor system for machining a workpiece, comprising - a housing (21) for manually guiding the handpiece (3), which comprises a first housing end (27) and a second housing end (28), - a tool holder (31) for fastening a machining tool (32), which is arranged at the first housing end (27), - an electric drive motor (45) arranged in the housing (21) and comprising a drive shaft (52) for rotating the tool holder (31) about a rotation axis (36), and - a fan (62) for generating an air flow (L) in a flow direction (S) from the fan (62) to the electric drive motor (45), wherein — the fan (62) is arranged between the electric drive motor (45) and the second housing end (28) and — the fan (62) is connected to the drive shaft (52).

2. Handpiece according to claim 1, characterized in that an air guide component (55) for mounting the electric drive motor (45) on the fan side and for guiding the air flow (L) is arranged in the housing (21).

3. Handpiece according to claim 2, characterized in that the air guide component (55) rests against the housing (21) and forms a fan-side bearing (58) for supporting the electric drive motor (45).

4. Handpiece according to at least one of claims 2 or 3, characterized in that the air guiding component (55) forms a receiving space (59) in which the fan (62) is arranged at least in sections.

5. Handpiece according to at least one of claims 2 to 4, characterized in that the air guiding component (55) forms at least one deflection channel (65) for guiding the air flow (L).

6. Handpiece according to claim 5, characterized in that an annular gap (66) is formed between the electric drive motor (45) and the housing (21), into which the at least one deflection channel (65) opens.

7. Handpiece according to at least one of claims 2 to 6, characterized in that the air guide component (55) comprises at least one line guide (73) for guiding a power supply line to the electric drive motor (45).

8. Handpiece according to at least one of claims 2 to 7, characterized in that a support element (67) is arranged between the air guide component (55) and the second housing end (28), against which the air guide component (55) rests.

9. Handpiece according to at least one of claims 2 to 8, characterized in that that in the flow direction (S) in front of the air guide component (55) a funnel component (71) is arranged to generate a suction effect.

10. Handpiece according to at least one of claims 1 to 9, characterized in that the electric drive motor (45) comprises a bearing plate (47) which is mounted on the housing (21).

11. Handpiece according to at least one of claims 1 to 10, characterized in that a tubular multifunctional component (75) for air guidance and support is arranged between the fan (62) and the second housing end (28).

12. Handpiece according to at least one of claims 1 to 11, characterized by a connection socket (76) for connecting at least one power supply line (13) and / or at least one signal line (19), which is connected in particular to a multifunctional component (75) at the second housing end (28).

13. Handpiece according to at least one of claims 1 to 12, characterized by an actuating unit (77) for actuating the electric drive motor (45), which is arranged in particular at least partially in an interior space (80) of a multifunctional component (75).

14. Micromotor system for machining a workpiece, comprising a handpiece (3), in particular according to at least one of the preceding claims, and a control unit (2) for controlling the handpiece (3).

15. Micromotor system according to claim 14, characterized by a transmission device (5) for the bidirectional transmission of data and / or signals between the control unit (2) and the handpiece (3).

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