hand tool

Abstract

A hand-held power tool (100) is disclosed, comprising a housing (110), a drive motor (114), an intermediate shaft (120), the intermediate shaft (120) being drivable by the drive motor (114), an impact mechanism (122) being drivable at least partially by the intermediate shaft (120), and a tool holder (150) for receiving an insert tool (140), the tool holder (150) being drivable by means of the impact mechanism (122). It is proposed that the hand-held power tool (100) has a sensor unit (200) which is designed to determine a rotation angle per impact of the impact mechanism (122).

Description

The present invention relates to a hand-held power tool according to the preamble of claim 1.Prior ArtDE 10 2019 204 071 A1 discloses a hand-held power tool in which a striking of a striking mechanism can be detected.Disclosure of the InventionThe present invention is based on a hand-held power tool having a housing, having a drive motor, having an intermediate shaft, the intermediate shaft being drivable by the drive motor, having a striking mechanism which is drivable at least partially by the intermediate shaft, and having a tool receptacle for receiving an insert tool, the tool receptacle being drivable by means of the striking mechanism. It is proposed that the hand-held power tool has a sensor unit which is designed to determine a rotation angle per stroke of the striking mechanism.The invention provides a hand-held power tool in which a screwing-in accuracy is increased by the hand-held power tool having the sensor unit for determining the angle of rotation per stroke of the striking mechanism. In DE 10 2019 204 071 A1, it is only possible to detect in the striking mechanism whether or not a strike has occurred. The present invention enables it to be detected by which angle of rotation the tool holder has been rotated further. This enables the higher screwing-in accuracy and an increase in user comfort.The hand-held power tool can be designed as an electrically operated hand-held power tool. The electrically operated hand-held power tool can be designed as a mains-operated or as a battery-operated hand-held power tool. For example, the hand-held power tool can be designed as a rotary impact wrench.The housing of the hand-held power tool is designed to at least partially accommodate the tool holder, the drive motor, the intermediate shaft and the striking mechanism. The housing can be designed as a shell housing with two half shells.The drive motor can be designed as an electrically commutated drive motor, in particular as at least one electric motor. The drive motor is designed in such a way that it can be actuated via a manual switch. If the hand switch is operated by a user, the drive motor is switched on and the hand-held power tool is put into operation. If the manual switch is accordingly no longer actuated by the user, the drive motor is switched off. The drive motor is preferably electronically controllable and / or regulable in such a way that a reversing operation and a specification for a desired rotational speed can be realized. In the reversing mode, the drive motor can be switchable between a clockwise direction of rotation and a counterclockwise direction of rotation. To switch over the drive motor in the reversing mode, the hand-held power tool can have a rotation direction switching element, in particular a rotation direction switching device.The drive motor is designed to drive the intermediate shaft. For this purpose, the drive motor and the intermediate shaft are connected to one another. The intermediate shaft is arranged between the drive motor and the tool holder. The intermediate shaft can have a transmission unit. The transmission unit can be designed as at least one planetary gear, wherein it can be shifted, for example. The planetary gear can have at least one planetary stage. In a shiftable transmission, it is possible to switch between at least two gear stages by means of at least one gear switching element, in particular a gear change-over switch. The transmission unit can have a transmission cover. The transmission cover is designed to cover, in particular at least partially close, the transmission unit with respect to the drive motor. The transmission cover can be arranged between the planetary transmission, in particular the planetary stage, and the drive motor. The transmission unit, in particular the planetary transmission, can have a ring gear. Here, for example, the ring gear and the transmission cover can be integral.The striking mechanism is designed to be operated in a striking mode. During the percussion operation, the percussion mechanism generates high torque peaks in order to thereby release tightly seated connecting means or to fasten connecting means. The striking mechanism has a striking mechanism and a striking mechanism spring. The striking mechanism can be connected to the drive motor by means of the gear unit of the intermediate shaft. The striking mechanism can be designed, for example, as a rotary striking mechanism or a V-groove striking mechanism. The striking mechanism can be driven by the intermediate shaft. The striking mechanism can be arranged between the drive motor and the tool holder. The striking mechanism has a striking mechanism housing in which the striking mechanism and the striking mechanism spring are arranged. In addition, the striking mechanism has a striking mechanism cover. The striking mechanism cover can close the striking mechanism in the direction of the drive motor. The striking mechanism cover can be arranged between the drive motor and the tool holder, in particular the intermediate shaft, very particularly the transmission unit. It is possible for the striking mechanism cover and the transmission cover to be integral, so that the striking mechanism cover forms the ring gear.The striker and the striking mechanism spring can be arranged around the intermediate shaft in the circumferential direction. The striker can be mounted on the intermediate shaft by means of striking mechanism balls. In addition, the striking mechanism balls are designed to move the striking element at least partially, in particular axially, in the direction of the drive motor. The striker can be arranged in a position facing the tool holder or in a position facing the drive motor. In the position facing the tool holder, the striker can abut a rear end of the tool holder by means of at least one striking cam. Here, for example, two striking cams are provided, wherein more than two striking cams are also conceivable. In the position facing the drive motor, the striker can be arranged at a distance from the tool holder. The striking mechanism balls are designed to pull the striking mechanism open from a triggering torque, which can be applied to the tool holder, in that the striking mechanism balls move, in particular displace, the striking mechanism from the position facing the tool holder counter to a spring force of the striking mechanism spring into the position facing the drive motor. The performed spring force of the striking mechanism spring is stored as the performed clamping work. As soon as the striker reaches the position facing the drive motor, the striker can be guided back into the position facing the tool holder by means of the striking mechanism spring. In this case, the clamping work performed is released, as a result of which the club is guided into the position facing the tool holder. The club can perform a rotational movement and an axial movement.The drive motor has a drive shaft. The drive shaft is mounted in the housing by means of at least one drive shaft bearing. The drive motor can drive by means of the drive shaft, the intermediate shaft, the transmission unit, the striking mechanism and / or the tool holder. The drive shaft bearing can be designed, for example, as a ball bearing, a rolling bearing or a sliding bearing. The drive shaft bearing is arranged at an end of the drive motor facing the tool holder. The drive shaft can project into the intermediate shaft through the transmission unit. The drive shaft bearing can be arranged in the intermediate shaft, so that the drive shaft is mounted in the intermediate shaft by means of the drive shaft bearing. The drive shaft can have a further drive shaft bearing which is arranged on an end facing away from the drive motor. Thus, the drive shaft can then be rotatably mounted in the housing by means of the drive shaft bearing and the further drive shaft bearing. It is possible for the drive shaft to protrude into the transmission cover and / or to engage into the transmission cover. The hand-held power tool can have a tool axis. In this case, an axis of rotation of the drive shaft can form the tool axis. In particular, "axial" is to be understood to mean substantially parallel to the tool axis. Whereas, "radial" is to be understood to mean substantially perpendicular to the tool axis.The tool holder can be designed as an inner tool holder, such as a bit holder, for example, and / or as an outer tool holder, such as a nut holder, for example. It is also conceivable for the tool holder to be designed as a drill chuck. The tool holder can hold insert tools, such as, for example, helical bits or socket wrench, so that a user can produce screw connections from a fastening element to a fastening carrier.In addition, the hand-held power tool comprises an energy supply, wherein the energy supply is provided for battery operation by means of batteries, in particular hand-held power tool battery packs, and / or for grid operation. In a preferred embodiment, the energy supply is designed for battery operation. In the context of the present invention, a "hand-held power tool battery pack" is intended to mean a connection of at least one battery cell and one battery pack housing. The handheld power tool rechargeable battery pack is advantageously designed for supplying energy to commercially available battery-operated handheld power tools. The at least one battery cell can be designed, for example, as a Lilon battery cell having a rated voltage of 3.6 V. By way of example, the handheld power tool battery pack can comprise up to ten battery cells, wherein a different number of battery cells is also conceivable. An embodiment as a battery-operated hand-held power tool and also the operation as a mains-operated hand-held power tool are sufficiently known to the person skilled in the art, for which reason the details of the energy supply will not be discussed here.The hand-held power tool can have a control unit at least for controlling the drive motor. The control unit can be arranged in the housing, for example in a handle of the hand-held power tool or in a region of a power supply interface.The sensor unit can be arranged in, on and / or around the housing. The sensor unit is designed to determine the angle of rotation per stroke of the striking mechanism. The sensor unit is configured to determine the angle of rotation by which the tool holder continues to rotate when the club strikes the tool holder in the circumferential direction. When the club impacts the fastener, the fastener continues to rotate in the rotational direction. The fastening element can be, for example, a screw or a nut.In one embodiment of the hand-held power tool, the sensor unit is arranged in the circumferential direction with respect to the tool holder. The sensor unit can be arranged on the tool holder in the circumferential direction to the tool axis. The sensor unit and the tool holder can be substantially coaxial. The sensor unit can be connected to the housing and / or the striking mechanism housing. It is possible for the sensor unit to be designed as a type of attachment or adapter for reversible connection to the hand-held power tool.In one embodiment of the hand-held power tool, the sensor unit has at least one running element and at least one sensor element, wherein the sensor element is designed to detect a change in the running element. The running element is configured to be movable, in particular rotatable. The running element can be magnetic. The running element can be designed, for example, as a magnetized sleeve, a disk, a pot or a hollow cylinder. Furthermore, the sensor element can be designed to detect a movement, in particular a rotation, of the running element. The sensor element can be designed to detect a magnetic field change. The sensor unit can have a sensor unit housing. The running element and / or the sensor element can be arranged substantially within the sensor unit housing. The sensor element may be arranged on a sensor board. The sensor board can be arranged substantially within the sensor unit housing. It is conceivable that a plurality of sensor elements are provided. For example, two or three sensor elements may be provided. The plurality of sensor elements may be arranged opposite to each other.In one embodiment of the hand-held power tool, the running element is connected to the tool holder. The running element can be connected to the tool holder at least in a positively locking manner, wherein it is also conceivable for these to be connected in a force-fit and / or firmly bonded manner. Furthermore, it is also possible for the running element and the tool holder to be integral. The running element can be connected to the tool holder in a rotationally fixed manner. The running element can be rotatable relative to the housing and / or the striking mechanism housing. The tool holder can have a connecting element. The connecting element can be designed to connect the running element to the tool holder. The connecting element can be formed, for example, as a circumferential web. The tool holder can form the connecting element, so that these are integral. The running element can be connected to the connecting element in a form-fitting, force-fitting and / or materially integral manner.In one embodiment of the hand-held power tool, the hand-held power tool has a bearing element which is designed to rotatably mount the running element relative to the housing. The bearing element can be designed as a bearing, such as a ball bearing, a plain bearing or a needle bearing. By means of the bearing element, the running element can be rotatable relative to the housing and / or striking mechanism housing.In one embodiment of the hand-held power tool, the bearing element is arranged radially between the housing and the running element. The bearing element can be arranged radially to the tool axis between the striking mechanism housing and the running element. A further bearing element can be provided. The further bearing element can be arranged radially to the tool axis between the running element and the housing, in particular the striking mechanism housing. The bearing element enables the running element to be mounted rotatably with respect to the tool holder. The further bearing element enables a rotational accuracy to be increased. The striking mechanism housing has a receptacle for the bearing element. The receptacle for the bearing element is formed in the circumferential direction with respect to the tool axis. The receptacle for the bearing element can be formed, for example, as a circumferential groove. The striking mechanism housing can have an annular receptacle or a further receptacle for the further bearing element. The running element can enter the further receptacle. The further bearing element can be arranged in the further receptacle. The tool holder or the output shaft has at least one bearing which is designed to rotatably mount the tool holder or the output shaft. The striking mechanism housing can have a neck, wherein the bearing for the output shaft can be arranged at least partially in the neck. The neck of the striking mechanism housing can be arranged radially to the tool axis between the bearing for the output shaft or the tool holder and the bearing element or the further bearing element.In one embodiment of the hand-held power tool, the sensor element is arranged radially, in particular with respect to the tool axis, between the running element and the sensor unit housing. The sensor unit housing is a housing of the sensor unit. The sensor unit housing can be designed, for example, in the manner of a sleeve, a cap or a pot. The sensor unit housing can have an opening for the tool holder. The tool holder can engage at least in sections through the opening for the tool holder. The sensor element can at least partially enter into an annular receptacle of the striking mechanism housing.In one embodiment of the hand-held power tool, the sensor element is arranged axially, in particular with respect to the tool axis, between the striking mechanism, in particular the striking mechanism housing, and the sensor unit housing. If the plurality of sensor elements is provided, one of the sensor elements can be arranged radially and a further sensor element can be arranged axially in the sensor unit housingThe invention also relates to a method for determining a work progress in the hand-held power tool, in particular the rotary impact wrench, with the tool holder and with the striking mechanism, comprising the method steps:determining a further rotation angle of the tool holder upon a strike of the striking mechanism;determining a magnetic field change of the running element connected to the tool holder in a rotationally fixed manner; determining the work progress on the basis of the determined further rotational angle and the determined magnetic field change.The progress of the work is linked to a striking energy of the striking mechanism. The impact energy is used to screw the fastening element, such as the screw, further into the fastening carrier or to loosen it therefrom. The proposed method can be used in a screwing-in as well as in a unscrewing direction. The further rotation angle can be determined by means of the running element and the sensor element. The magnetic field change is determined by means of the running element and the sensor element. In this case, there is a correlation between the further angle of rotation and the magnetic field change, so that the progress of the work can be deduced therefrom. It is conceivable that the magnetic field change is detected incrementally or by means of an encoder disk or the like.Furthermore, the present invention proceeds from the control unit for the above-described hand-held power tool, comprising means for carrying out the steps of the above-described method.Brief Description of the DrawingsThe invention is explained below with reference to a preferred embodiment. The drawings show: FIG. 1 shows a schematic view of a hand-held power tool according to the invention; FIG. 2 shows a detail of a longitudinal section of the hand-held power tool; FIG. 3 shows a flow diagram of a method according to the invention;DESCRIPTION OF THE EMBODIMENTFIG. 1 shows a hand-held power tool 100 according to the invention, wherein it is designed here as an exemplary battery-operated rotary impact wrench. The hand-held power tool 100 comprises an output shaft 124, a tool holder 150 and a striking mechanism 122, for example a rotary or rotary striking mechanism. The hand-held power tool 100 has a housing 110 with a handle 126. The hand-held power tool 100 can be connected mechanically and electrically to a power supply for battery operation to form a power supply independent of the grid, so that the hand-held power tool 100 is designed as a battery-operated hand-held power tool 100. A handheld power tool rechargeable battery pack 130 is used here as the energy supply. However, the present invention is not limited to battery-operated hand-held power tools, but can also be used in grid-dependent, i.e. grid-operated, hand-held power tools.The housing 110 comprises a drive unit 111 and the striking mechanism 122, wherein the drive unit 111 and the striking mechanism 122 are arranged in the housing 110. The drive unit 111 comprises an electrically commutated drive motor 114, which is supplied with current by the handheld power tool rechargeable battery pack 130, and a transmission unit 118. The transmission unit 118 is designed as at least one planetary gear. The drive motor 114 is designed such that it can be actuated, for example, via a manual switch 128, with the result that the drive motor 114 can be switched on and off. The drive motor 114 can advantageously be controlled and / or regulated electronically, so that a reversing operation, as well as a desired rotational speed, can be realized. For the reversing operation, the hand-held power tool 100 has a rotation direction switching element 121, which is designed as a rotation direction switcher. The rotation direction switching member 121 is configured to switch the drive motor 114 between a clockwise rotation direction and a counterclockwise rotation direction. The structure and the mode of operation of a suitable drive motor are sufficiently known to the person skilled in the art, for which reason they will not be discussed in more detail here.The gear unit 118 is connected to the drive motor 114 via a drive shaft 116. The drive shaft 116 is mounted in the housing 110 by means of a motor-side bearing, not shown in detail. The transmission unit 118 is provided to convert a rotation of the drive shaft 116 into a rotation between the transmission unit 118 and the striking mechanism 122 via an intermediate shaft 120. Preferably, this conversion is such that the intermediate shaft 120 rotates relative to the input shaft 116 at an increased torque but at a decreased rotational speed. The intermediate shaft 120 drives the striking mechanism 122 at least partially. The transmission unit 118 includes a transmission case 119 disposed in the housing 110. The hand-held power tool 100 comprises a tool axis 102, wherein here an axis of rotation of the drive shaft 116 forms the tool axis 102.The striking mechanism 122 is connected to the intermediate shaft 120 and comprises a striking element 300 and a striking-element spring 350, wherein the striking mechanism 122 generates abrupt rotational pulses with high intensity during a striking operation, see also FIG. 2. These abrupt rotational pulses are transmitted via the striking element 300 to the output shaft 124, for example a work spindle. The striking mechanism 122 comprises a striking mechanism housing 123, wherein the striking mechanism 122 can also be arranged in another suitable housing, such as the transmission housing 119. The striking mechanism 122 is designed to drive the output shaft 124. A tool holder 150 is provided on the output shaft 124. The tool holder 150 is preferably formed and / or formed on the output shaft 124. The tool holder 150 is preferably arranged in an axial direction 132 facing away from the drive unit 111. The tool holder 150 is designed here as an internal hexagonal holder, in the manner of a bit holder, which is provided to receive an insert tool 140. The insert tool is shaped in the manner of a screwdriver bit with a polygonal outer coupling 142. The type of screwdriver bit, for example of the HEX type, is sufficiently known to the person skilled in the art. In FIG. 2, the tool holder 140 is formed as an outer square holder for receiving plug-in nuts. However, the present invention is not limited to the use of HEX screwdriver bits or plug nuts, but other tool holders that appear expedient to the skilled person can also be used, such as HEX drills, SDS quick inserts or round shank drill chucks. In addition, the structure and the mode of operation of a suitable bit holder are sufficiently known to the person skilled in the art.The hand-held power tool 100 has a control unit 170 at least for controlling the drive unit 111, in particular the drive motor 114, and for carrying out a method 400. The housing 110 at least partially receives the control unit 170. The control unit 170 has a microprocessor, not shown in detail. In addition, the housing 110 includes a power supply holder 160. The energy supply holding device 160 accommodates the handheld power tool battery pack 130 and forms a stand 162 with a standing surface. The handheld power tool rechargeable battery pack 130 can be detached from the energy supply holding device 160 without tools. Further, the housing 110 includes the handle 126 and the power supply holder 160. The handle 126 may be grasped by the user. In one embodiment, the power supply holder 160 is disposed on the handle 126. The hand-held power tool 100 can be set down by means of the stand 162.The hand-held power tool 100 comprises a sensor unit 200. The sensor unit 200 is provided to ascertain a rotation angle per stroke of the striking mechanism 122. The sensor unit 200 is arranged, for example, on the housing 110, see also FIG. 2, The sensor unit 200 is arranged in the circumferential direction with respect to the tool holder 102 and the tool holder 150. The sensor unit 200 and the tool holder 150 are substantially coaxial. The sensor unit 200 is connected by way of example to the striking mechanism housing 123, see also FIG. 2.FIG. 2 shows a detail 500 of a longitudinal section of the hand-held power tool 100. The drive shaft 116 is mounted in the intermediate shaft 120 by means of a drive shaft bearing 117. The drive shaft bearing 117 is formed here as a needle bearing, for example. The striking mechanism 122 is formed here as a V-groove striking mechanism. A striker 300 and a striking mechanism spring 350 are arranged in the striking mechanism housing 123. The striker 300 is mounted on the intermediate shaft 120 by means of striking mechanism balls 310. The striking mechanism balls 310 are provided to move the striking mechanism 300 at least partially in the direction of the drive motor 114. The striking mechanism spring 350 is arranged around the intermediate shaft 120 in the circumferential direction and encloses the latter accordingly in the circumferential direction with respect to the tool axis 102.The sensor unit 200 comprises a running element 220 and a sensor element 230. The sensor element 230 is provided to detect a change of the running element 220. The running element 220 is formed rotatably relative to the striking mechanism housing 123. Here, the running element 220 is formed as a magnetized sleeve, for example. Sensor element 230 is provided to detect a magnetic field change. The sensor unit 200 includes a sensor unit housing 210. Both the running element 220 and the sensor element 230 are arranged substantially within the sensor unit housing 210. The sensor unit 200 has a sensor unit board 232 on which the sensor element 230 is arranged. The sensor board 232 is substantially disposed inside the sensor unit housing 210. The sensor unit housing 210 is formed in the manner of a cap, for example. Here, the sensor unit housing 210 comprises an opening 212 for the tool holder 150, wherein the tool holder 150 engages at least in sections through the opening 212 for the tool holder 150.The running element 220 is connected to the tool holder 150 in a rotationally fixed and at least positively locking manner. For this purpose, the tool holder 150 comprises a connecting element 156, which is designed to connect the running element 220 to the tool holder 150. By way of example, the connecting element 156 is formed as a circumferential web. The tool holder 150 and the connecting element 156 are integral. The running element 220 and the connecting element 156 are connected to one another at least in a positively locking manner.The hand-held power tool 100 comprises a bearing element 240. The bearing element 240 is designed to rotatably support the running element 220 relative to the housing 110, in particular the striking mechanism housing 123. The bearing element 240 is formed, for example, as a slide bearing. The bearing element 240 is arranged radially to the tool axis 102 between the housing 110, in particular the striking mechanism housing 123, and the running element 220. The hand tool 100 comprises a further mounting element 242. The further bearing element 242 is arranged radially to the tool axis 102 between the running element 220 and the housing 110, in particular the striking mechanism housing 123. The striking mechanism housing 123 comprises a receptacle 250 for the bearing element 240 which is formed on the striking mechanism housing 123 in the circumferential direction with respect to the tool axis 102. By way of example, the receptacle 250 for the bearing element 220 is formed as a circumferential groove. The striking mechanism housing 123 comprises a further receptacle 252 for the further bearing element 242. The further receptacle 252 for the further bearing element 242 is formed, for example, as an annular receptacle. The running element 220 is designed to be inserted at least in sections into the further receptacle 252. The further bearing element 242 is arranged in the further receptacle 252. The output shaft 124 includes a bearing 158. The bearing 158 is configured to rotatably support the output shaft 124. The striking mechanism housing 123 comprises a neck 136. The bearing 158 for the output shaft 124 is at least partially disposed in the neck 136. The neck 136 of the striking mechanism housing 123 is arranged radially with respect to the tool axis 102 between the bearing 158 for the output shaft 124 and the bearing element 240 and / or the further bearing element 242. Sensor element 230 is situated radially, in particular to tool axis 102, between running element 220 and sensor unit housing 210.FIG. 3 shows a flow diagram 600 of a method 400 according to the invention. Method 400 is used to determine a work progress of handheld power tool 100. In a method step 610, a further angle of rotation of the tool holder 150 is determined upon a strike of the striking mechanism 122. In a method step 620, a magnetic field change of the running element 220 connected to the tool holder 150 in a rotationally fixed manner is determined, in particular by means of the sensor element 230. In a method step, the progress of the work is determined on the basis of the determined further rotation angle and the determined magnetic field change.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2019 204 071 A1 [0002, 0004]

Claims

Hand-held power tool (100) having a housing (110), having a drive motor (114), having an intermediate shaft (120), the intermediate shaft (120) being drivable by the drive motor (114), having a striking mechanism (122) which is drivable at least partially by the intermediate shaft (120), and having a tool receptacle (150) for receiving an insert tool (140), the tool receptacle (150) being drivable by means of the striking mechanism (122), characterized bya sensor unit (200) which is designed to determine an angle of rotation per strike of the striking mechanism (122).Hand-held power tool (100) according to Claim 1, characterized in that the sensor unit (200) is arranged in the circumferential direction with respect to the tool holder (150).Hand-held power tool (100) according to Claim 1 or 2, characterized in that the sensor unit (200) has at least one running element (220) and at least one sensor element (230), wherein the sensor element (230) is designed to detect a change in the running element (220).Hand-held power tool (100) according to Claim 3, characterized in that the running element (220) is connected to the tool holder (150).Hand-held power tool (100) according to Claim 3 or 4, characterized bya bearing element (240) which is designed to rotatably mount the running element (220) relative to the housing (110).Hand-held power tool (100) according to Claim 5, characterized in that the bearing element (240) is arranged radially between the housing (120) and the running element (220).Hand-held power tool (100) according to one of Claims 3 to 6, characterized in that the sensor element (230) is arranged radially between the running element (220) and a sensor unit housing (210).Hand-held power tool (100) according to one of Claims 3 to 7, characterized in that the sensor element (230) is arranged axially between the striking mechanism (122) and a sensor unit housing (210).Method (400) for determining a work progress in a hand-held power tool (100), in particular a rotary impact screwdriver, having a tool holder (150) and having a striking mechanism (122), comprising the method steps: - determining a further rotation angle of the tool holder (150) in the event of a strike of the striking mechanism (122); - determining a magnetic field change of a running element (220) which is connected to the tool holder (150) in a rotationally fixed manner; and determining the work progress on the basis of the determined further rotation angle and the determined magnetic field change.Control unit (170) for a hand-held power tool (100) according to one of Claims 1 to 8, comprising means for carrying out the steps of the method (400) according to Claim 9.

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