Cordless drill

Abstract

Cordless drill with a drive unit (74) for driving a drill spindle (14) about a tool axis (12), with a housing (16) which has a housing unit (18) which at least partially surrounds the drill spindle (14) and extends at least substantially parallel to the tool axis (12), and with a handle unit (20) arranged on an end (24) of the housing unit (18) facing away from the drill spindle (14), the handle axis (22) of which forms an angle (72) of between 70° and 90° with the tool axis (12), wherein the drive unit (74) has an electronically commutated motor (34) for driving the drill spindle (14) with a working movement (52) at a speed greater than 2000 rpm, characterized by a locking device (36) by means of which the drill spindle (14) can be fixed in a rotationally fixed manner with respect to the housing (16) in such a way that is,that the locking device (36) opens automatically when torque is transmitted from the motor (34) to the drilling spindle (14) and closes automatically when torque is transmitted from the drilling spindle (14) to the motor (34).

Description

State of the art

[0001] Cordless drills with a drive unit designed to drive a drill spindle about a tool axis, with a housing having a housing unit that at least partially surrounds the drill spindle and extends at least substantially parallel to the tool axis, and with a handle unit arranged at an end of the housing unit facing away from the drill spindle, the handle axis of which forms an angle of between 70° and 90° with the tool axis, are already known. Corresponding cordless drills with a pistol-type housing are known, for example, from DE 10 2009 027 111 A1 and DE 10 2010 056 120 A1, while DE 10 2010 056 524 A1 shows a predominantly straight cordless screwdriver having a tool axis arranged at a right angle to one end of its handle unit.

[0002] DE 10 2011 004 495 A1 further shows a cordless drill driver with a gun housing and a drive unit arranged in the gun housing for driving a spindle via a single-stage planetary gear, wherein the drive unit has an electronically commutated motor which can drive the spindle at a speed of more than 2000 rpm. Disclosure of the invention

[0003] The invention is based on a cordless drill with a drive unit for driving a drill spindle about a tool axis, with a housing which has a housing unit which at least partially surrounds the drill spindle and extends at least substantially parallel to the tool axis, and with a handle unit which is arranged at an end of the housing unit facing away from the drill spindle and whose handle axis forms an angle of between 70° and 90° with the tool axis, wherein the drive unit has an electronically commutated motor for driving the drill spindle with a working movement at a speed of greater than 2000 rpm.

[0004] A locking device for a cordless drill is proposed, by means of which the drill spindle can be fixed in relation to the housing in a rotationally fixed manner such that the locking device opens automatically when torque is transmitted from the motor to the drill spindle and closes automatically when torque is transmitted from the drill spindle to the motor. Clamping and / or releasing the tool can thus be particularly convenient. Concomitant rotation of the motor can be avoided. The torque required for clamping or releasing can be effectively supported on the housing. The user can clamp or release a tool particularly easily by turning a clamping ring of a chuck arranged on the drill spindle. In this context, a chuck is to be understood in particular as a bearing device for a tool, in particular a drilling tool, which is intended to secure the tool by clamping.Tools can advantageously be clamped to the cordless drill. The user can change tools quickly and easily. In particular, the locking device can automatically secure the drill spindle when the user applies torque to the clamping ring of the chuck. In particular, the locking device can automatically release the drill spindle when the motor applies torque to the planetary gear to drive the drill spindle. Such a locking device can have a driving contour drivable by the planetary gear, which is intended to transmit torque to a driving contour that is connected to the drill spindle in a rotationally fixed manner by means of a positive connection. The driving contours can be designed such that projections of the driving contour of the planetary gear, arranged in pairs, engage claws of the driving contour of the drill spindle.A gap can be provided between the projections and the claws so that the driving contours exhibit rotational play. Spherical or cylindrical clamping bodies, in particular, can be provided in additional gaps between the paired projections. The driving contours can be surrounded by a retaining ring that is connected to the housing in a rotationally fixed manner. The driving contour on the drill spindle side can have flattened areas onto which the clamping bodies run when the drill spindle is rotated, clamping the drill spindle to the retaining ring. This allows for effective, rotationally fixed fastening of the drill spindle to the housing. Tool changes can be particularly convenient.

[0005] In this context, a "cordless drill" is understood to mean, in particular, a handheld power tool with an energy supply via a power tool battery, which is intended to drive a tool with a rotating working movement in at least one operating state. A "power tool battery" is understood to mean, in particular, a battery intended to supply a handheld power tool with electrical energy. In particular, the power tool battery can be designed as an easily replaceable battery module. The power tool battery is advantageously specially protected against dust and dirt and / or adapted to the power of the handheld power tool. The power tool battery preferably has a plurality of cells and / or a voltage greater than 3.6 volts, advantageously greater than 10 volts. The power tool battery particularly advantageously has lithium cells.In particular, the power tool battery is intended to deliver a power of greater than 25 watts, advantageously greater than 50 watts, and particularly advantageously greater than 100 watts. In particular, the power tool battery is intended to supply a drive unit of a handheld power tool with electrical power. In this context, a "drive unit" is to be understood in particular as a unit that is intended to generate a working movement, in particular a rotating working movement. Advantageously, the rotating working movement is intended in particular to enable drilling of a workpiece using a drill. Advantageously, the drive unit has a motor and a gear unit. The gear unit is preferably intended to generate the speed of the working movement from a drive movement of the motor. The motor can preferably be designed as a "rare earth motor".In this context, this should be understood in particular as a motor having at least one rare earth permanent magnet containing a magnetic material formed at least partially from a metal from the rare earth group. The rare earth motor can advantageously have at least one rare earth permanent magnet containing an alloy containing neodymium and / or samarium. The rare earth motor particularly advantageously has at least one samarium-cobalt and / or neodymium-iron-boron permanent magnet. The rare earth motor can be designed as a DC motor whose stator has the at least one rare earth permanent magnet, or particularly advantageously as an electronically commutated motor whose rotor has the at least one rare earth permanent magnet. An electronically commutated motor can be particularly durable and / or overload-resistant.The rare earth motor can have a particularly high power density. The rare earth motor can be particularly compact. The rare earth motor can have a particularly high efficiency. A particularly compact power tool battery can be used. The housing unit and / or the handle unit can be particularly compact. The housing unit and / or the handle unit can be particularly ergonomic. The user can grip the housing unit and / or the handle unit in a particularly advantageous gripping position and / or guide the cordless drill particularly safely.

[0006] The cordless drill can be particularly suitable for drilling work, in particular for drilling work where a high speed of the drive movement is advantageous. It is also possible for the cordless drill to have a battery built into the housing, in particular into the handle unit, for power supply instead of or in addition to a replaceable machine tool battery. “Intended” should be understood to mean specially designed and / or equipped. Preferably, the cordless drill is intended for drilling work. The cordless drill can also be used for screwdriving and other work with a rotating tool. The cordless drill can be intended to superimpose at least one further working movement on the rotating working movement, in particular a percussive working movement for impact drilling operation.In this context, a “drill spindle” should be understood in particular to mean a rotatably mounted component which is intended to transmit the working movement to a tool, in particular a drill. In particular, the drill spindle can be intended to mount the tool on the cordless drill. In this context, a “housing” should be understood in particular to mean a protective housing which delimits the cordless drill to the outside. Preferably, the housing is formed at least partially from a plastic. The housing has at least one housing unit. In this context, “at least partially surrounded” should preferably be understood to mean that the housing unit surrounds at least partial regions of the drill spindle around the tool axis over an angle of at least 300°, preferably 360°. Preferably, the housing unit is designed as a motor housing.A “motor housing” is to be understood in particular as a housing that at least partially, preferably completely, surrounds a motor and / or a gear unit of the cordless drill. By “at least substantially parallel to the tool axis” is to be understood in this context in particular that a lateral surface of the housing unit has a basic shape that is preferably approximated to a cylindrical shape around the tool axis along more than 50% of its main extent. In this context, “approximately” is to be understood as a deviation of a radial distance of the lateral surface of the housing unit from the tool axis from a radial distance of a lateral surface of a largest cylinder inscribed in the lateral surface of the housing unit from the tool axis by less than 50%, preferably less than 30%, particularly preferably less than 15%.In this context, a "handle unit" should be understood in particular to mean a unit that is intended to be gripped by the user with at least part of one hand to guide the cordless drill. The handle unit can be designed as a separate handle attached to the cordless drill. In this context, an "end of the housing unit facing away from the drill spindle" should be understood in particular to mean the greatest extent of the housing unit on a side of the housing unit facing away from the drill spindle in the direction of the tool axis. The housing with the housing unit and the handle unit can preferably have a pistol shape. The user can grip the end of the housing unit facing away from the drill spindle together with the handle unit with one hand. When gripping the cordless drill, the user can advantageously position the ball of his hand close to the tool axis.In particular, a handle position can be such that the user's arm axis is close to or identical to the tool axis. The user can guide the cordless drill particularly precisely. The user can vary the pressure force particularly well when drilling with only slight deviations in the direction of the pressure force from the tool axis. A drilling process can be particularly precise. Preferably, the handle unit has a receiving area for a power tool battery. The power tool battery can advantageously be attached to the handle unit. The power tool battery can provide the cordless drill with a center of gravity that is advantageous for guiding the cordless drill.

[0007] It is further proposed that the drive unit have an at least single-stage planetary gear system provided for translating the drive movement. A "planetary gear system" in this context is understood to mean a gear system in which planetary gears are arranged so as to revolve around a sun gear. The planetary gear system is preferably single-stage. The planetary gear system is particularly provided for converting the drive movement of the motor into the rotating working movement of the drill spindle. A speed ratio between the motor and the drill spindle is preferably 1 / 5 - 1 / 7. An idle speed of the working movement of the drill spindle is preferably 2500 - 4500 rpm, particularly preferably 4000 rpm.In this context, "idling speed" is understood to mean a speed when the tool switch is fully depressed by the user, whereby the drill spindle and / or the chuck and / or a tool clamped in the chuck remains contactless with the surroundings of the cordless drill. A planetary gear unit can be particularly compact. The size of the housing unit and / or the handle unit can be further reduced. The housing unit and / or the handle unit can be particularly ergonomic. The user can grip the housing unit and / or the handle unit in a particularly advantageous gripping position and / or guide the cordless drill particularly safely.

[0008] It is further proposed that a planet carrier of the planetary gear is part of the locking device. In particular, the planet carrier can have the driving contour, which is provided to transmit a torque, in particular a working torque of the working movement, to at least one further contour of the locking device depending on an operating state. In particular, the driving contour can have projections aligned axially in the direction of the chuck. Components can be saved. The planetary gear and the locking device can be particularly reliable and / or cost-effective. The size of the housing unit can be further reduced. The housing unit can be particularly ergonomic. The user can grip the housing unit in a particularly advantageous gripping position and / or guide the cordless drill particularly safely.

[0009] In a particularly advantageous embodiment of the invention, it is proposed that the handle unit projects beyond the housing unit in a direction facing away from the drill spindle. The user can position his hand particularly close to the tool axis when gripping the cordless drill. It is further proposed that the handle unit forms part of the housing. A "part of the housing" should be understood to mean parts of the housing that are inseparably connected, particularly for the user. Preferably, the handle unit and the housing unit of the housing can be formed at least partially in one piece. In this context, "one piece" should be understood to mean, in particular, connected by a material fit, for example by a welding process and / or gluing process, etc., and particularly advantageously, molded onto the housing, such as by production from a single casting and / or by production using a single or multi-component injection molding process.The housing of the cordless drill can be particularly robust. In a further preferred embodiment of the invention, the motor can be at least partially arranged in the handle unit. The housing unit surrounding the drill spindle can be particularly slim. The housing unit can have a shape that is particularly well suited to being gripped by the user with one hand together with the handle unit. Particularly preferably, the handle unit has a tool switch on a side facing the drill spindle. In this context, a "tool switch" is understood to mean a switch with which the user can start the cordless drill and / or influence the speed of the drill spindle and / or the motor.

[0010] It is proposed that the housing unit be at least partially designed as a gripping surface. The gripping surface preferably has a shape and texture that allows a comfortable, secure grip by the user. The motor is preferably arranged in the housing unit. The user can at least partially grasp the motor when gripping the housing unit. A space surrounded by the gripping surface can be advantageously utilized.

[0011] Particularly advantageously, the gripping surface of the housing unit has a pressure surface which is arranged at the end of the housing unit facing away from the drill spindle, at least substantially centrally to the tool axis. Particularly preferably, the pressure surface is set back in the direction of the drill spindle. Preferably, regions of the gripping surface of the housing unit arranged in the direction of the gripping unit and in a direction facing away from the gripping unit project beyond the pressure surface in a direction facing away from the drill spindle. Particularly preferably, the housing unit has at least one gripping recess in the direction of the drill spindle adjacent to the pressure surface. Preferably, the housing unit has gripping recesses on both sides starting from the pressure surface.In this context, the “sides” of the housing unit should be understood to mean, in particular, areas of the casing surface of the housing unit that are delimited by the handle unit and by an upper side of the housing unit facing away from the handle unit. The user can grip the cordless drill particularly well so that their arm axis is at least close to the tool axis. In particular, the user can comfortably grip the pressure surface with their thumb and index finger and place their thumb and / or index finger in the grip recesses. The user can comfortably grip the handle unit with the other three fingers and operate the tool switch. A particularly secure and comfortable grip on the cordless drill can be possible. The user can apply a contact force at least substantially in the direction of and / or centrally to the tool axis. The cordless drill can be operated particularly comfortably with either the right or left hand. drawing

[0012] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0013] They show: Fig. 1 a schematic representation of a cordless drill with a handle unit and Fig. 2 a schematic sectional view of the cordless drill. Description of the embodiment

[0014] Fig. 1 shows a cordless drill 10 with a drill spindle 14 that can be driven around a tool axis 12 ( Fig. 2) and a housing 16, which has a housing unit 18 surrounding the drill spindle 14 and extending parallel to the tool axis 12. A handle unit 20, the handle axis 22 of which forms an angle 72 of 80° with the tool axis 12, is arranged at an end 24 of the housing unit 18 facing away from the drill spindle 14 and is formed integrally with the housing unit 18. The handle unit 20, together with the housing unit 18, forms part of the housing 16. The handle unit 20 projects beyond the housing unit 18 in a direction 26 facing away from the drill spindle 14. The housing unit 18 is partially formed as a handle surface 40. The handle surface 40 has a pressure surface 42, which is arranged essentially centrally to the tool axis 12 at the end 24 of the housing unit 18 facing away from the drill spindle 14. A tool switch 44 is arranged on the handle unit 20 on a side facing the drill spindle 14.A user grips the cordless drill 10 with one hand, using their thumb and index finger to grip the gripping surface 40 of the housing unit 18. With the other fingers, the user grips the handle unit 20, with the palm of their hand resting on a gripping surface 46 of the handle unit 20. The pressure surface 42 forms a recess 48 in the direction of the drill spindle 14, to which a gripping recess 50 is connected on each side, into which the user can place their thumb or index finger. The user can grip the cordless drill 10 securely and comfortably. In particular, they can grip the cordless drill 10 in the manner described so that the position and direction of their arm axis essentially corresponds to the tool axis 12. A pressure force can thus be exerted on the cordless drill 10 precisely and centrally to the tool axis 12, enabling precise and comfortable drilling.Furthermore, the handle unit 20 has a receiving area 68 for a power tool battery 70. The power tool battery 70 serves to supply power to the cordless drill 10. A drive unit 74 has a motor 34 designed as a rare-earth motor and a planetary gear 30 and serves to generate a rotating working movement 52 with a speed of more than 2000 rpm on the drill spindle 14. The motor 34 is designed as an electronically commutated motor whose rotor 76 has rare-earth magnets 78.

[0015] Fig.2 shows a section through the cordless drill 10. A chuck 28 is arranged on the drill spindle 14. The user can clamp a drill or similar tool in the chuck 28. The drill spindle 14 is driven in a rotating working movement 52 by the single-stage planetary gear 30 during drilling operation. The motor 34 arranged in the housing unit 18 drives the planetary gear 30. The planetary gear 30 transmits a drive movement 32 of the motor 34 to the drill spindle 14 at a ratio of 1:6. The idle speed of the working movement 52 is 4000 rpm, with the idle speed of the drive movement 32 of the motor 34 being 24000 rpm. The motor 34 is arranged in the housing unit 18 between the recessed grips 50 and is partially gripped by the user when gripping the cordless drill 10. The planetary gear 30 has a sun gear 56 which is connected to a motor shaft 58 of the motor 34.Planetary gears 54 roll on the sun gear 56. A planetary carrier 38 supports the planetary gears 54 and forms an output of the planetary gear 30.

[0016] The drilling spindle 14 can be rotationally fixed to the housing 16 via a locking device 36. The locking device 36 is designed such that it opens automatically when torque is transmitted from the motor 34 to the drilling spindle 14 and closes automatically when torque is transmitted from the drilling spindle 14 to the motor 34. The planet carrier 38 of the planetary gear 30 is part of the locking device 36. The locking device 36 has a retaining ring 60 which is rotationally fixedly connected to the housing 16. An eccentric 62 is rotationally fixedly connected to the drilling spindle 14. The planet carrier 38 has a driving contour with projections 64 designed as drivers. Roller bodies 66 are located in the spaces between the projections 64 and the eccentric 62. The eccentric 62 has inclined surfaces. When a user turns the chuck 28, the roller bodies 56 run onto the inclined surfaces.The roller bodies 66 clamp the eccentric 62 to the retaining ring 60, thus securing the eccentric 62 and thus the drill spindle 14 to the housing 14 in a rotationally fixed manner. When the eccentric 62 is driven by the planetary carrier 38 through a positive engagement of the projections 64, the roller bodies 66 roll off the inclined surfaces and release the eccentric 62, allowing the drill spindle 14 to be driven with the working movement 52. The locking device 36 is designed so that this process is possible in both counterclockwise and clockwise rotation.

Claims

[1] Cordless drill with a drive unit (74) for driving a drill spindle (14) about a tool axis (12), with a housing (16) having a housing unit (18) which at least partially surrounds the drill spindle (14) and extends at least substantially parallel to the tool axis (12), and with a handle unit (20) arranged on an end (24) of the housing unit (18) facing away from the drill spindle (14), the handle axis (22) of which forms an angle (72) of between 70° and 90° with the tool axis (12), wherein the drive unit (74) has an electronically commutated motor (34) for driving the drill spindle (14) with a working movement (52) at a speed greater than 2000 rpm, characterized bya locking device (36) by means of which the drilling spindle (14) can be fixed in a rotationally fixed manner with respect to the housing (16) in such a way that the locking device (36) opens automatically when torque is transmitted from the motor (34) to the drilling spindle (14) and closes automatically when torque is transmitted from the drilling spindle (14) to the motor (34). [2] Cordless drill according to claim 1, characterized by that the drive unit (74) has an at least single-stage planetary gear (30) for translating a drive movement (32). [3] Cordless drill according to one of the preceding claims, characterized by that a planet carrier (38) of the planetary gear (30) is part of the locking device (36). [4] Cordless drill according to one of the preceding claims, characterized by that the handle unit (20) projects beyond the housing unit (18) in a direction (26) facing away from the drill spindle (14). [5] Cordless drill according to one of the preceding claims, characterized by that the handle unit (20) forms part of the housing (16) [6] Cordless drill according to one of the preceding claims, characterized by that the housing unit (18) is at least partially designed as a gripping surface (40). [7] Cordless drill according to one of the preceding claims, characterized by a pressure surface (42) of the gripping surface (40), which is arranged at the end (24) of the housing unit (18) facing away from the drilling spindle (14) at least substantially centrally to the tool axis (12).

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