EP2855096A1

EP2855096A1 - Percussion unit

Info

Publication number: EP2855096A1
Application number: EP13720842.7A
Authority: EP
Inventors: Rainer Nitsche; Matthias Tauber; Gerd Schlesak; Antoine Vandamme; Thomas Winkler; Christian Bertsch; Achim Duesselberg; Ulli Hoffmann; Thilo Henke; Juergen Lennartz; Helge SPRENGER
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-05-25
Filing date: 2013-04-24
Publication date: 2015-04-08
Anticipated expiration: 2033-04-24
Also published as: RU2014152476A; US9969071B2; EP2855096B1; JP2015517412A; CN104334319A; WO2013174600A1; DE102012208913A1; US20150136433A1; JP5864818B2

Abstract

Percussion unit (10a-c), especially for a rotary hammer and/or percussion hammer (12a; 12c), comprising a control unit (14a; 14c) which is designed for open-loop and/or closed loop control of a pneumatic percussion mechanism (16a; 16c), and at least one operating condition sensor unit (18a). According to the invention, the control unit (14a; 14c) is designed to detect at least one percussion mechanism parameter depending on measurement values of the operating condition sensor unit (18a).

Description

description

Percussion unit

State of the art

There are already Schlagwerkinheiten, especially for a drill and / or percussion hammer, with a control unit, which is intended to control a pneumatic percussion, and at least one Betriebsbedingungssensor- unit known.

DISCLOSURE OF THE INVENTION The invention is based on a percussion unit, in particular for one

Drilling and / or percussion hammer, comprising a control unit, which is intended to control and / or regulate a pneumatic hammer mechanism, and at least one operating condition sensor unit. It is proposed that the control unit be provided to determine at least one striking mechanism parameter as a function of measured values of the operating condition sensor unit. By "provided" is intended to be understood in particular to be specially designed and / or specially equipped. "A percussion unit" is to be understood in this context, in particular, as a unit which is provided for operating a striking mechanism. The percussion unit may in particular have a control unit. The percussion unit may comprise a motor and / or a gear unit which is and / or which is provided for driving the Schlagwerkinheit. In this context, a "control unit" is to be understood as meaning, in particular, a device of the striking mechanism unit which is provided for controlling and / or regulating, in particular, the engine and / or the impact mechanism unit. unit may preferably be designed as electrical, in particular as an electronic control unit. In this context, a "hammer drill and / or percussion hammer" is to be understood as meaning, in particular, a machine tool which is provided for machining a workpiece with a rotating or non-rotating tool, the tool being able to be acted upon by the machine tool with impact pulses In this context, a "percussion mechanism" is to be understood as meaning, in particular, a device which has at least one component which results in the generation and / or transmission of a percussion pulse, in particular an axial impact impulse a tool arranged in a tool holder is provided. Such a component may in particular be a racket, a firing pin, a guide element, such as, in particular, a hammer tube and / or a piston, in particular a pot piston, and / or another component which appears expedient to the person skilled in the art. The bat can the

Impact impulse transferred directly to the tool or preferred indirectly. Preferably, the racket can transmit the impact pulse to a firing pin, which transmits the impact pulse to the tool. In this context, a "user condition sensor unit" is to be understood as meaning, in particular, a measuring device which is provided for operating conditions of the device

To detect percussion. The occupancy condition sensor unit may include one or more sensors. A sensor may be arranged on a circuit board of the control unit. A sensor arrangement can be particularly inexpensive. A sensor can be arranged on a hand-held power tool housing on an inner or an outer side. The sensor can record measured values particularly accurately within the handheld power tool or outside the handheld power tool. A sensor may be arranged on a main handle or an auxiliary handle. A sensor may be arranged on a motor or a guide tube. In particular, the sensor can detect measured values influenced by the motor and / or having an effect on guide properties of the guide tube. The Betnebsbedingungssensoreinheit may advantageously comprise one or more external sensors. In particular, the user condition sensor unit may communicate with sensors of external devices, such as a smartphone, and / or with sensors and / or operating condition data accessible via the Internet. The operating condition sensor unit may preferably be temperature and / or ambient Obtain air pressure data from external sensors. Sensors can be saved. The term "operating conditions" should be understood to mean, in particular, physical quantities which have an influence on the operation of the percussion mechanism Operating conditions may, in particular, be environmental conditions of an impact mechanism environment Schlagwerks can change by the operating conditions, such as in particular an efficiency and / or a startup behavior. In this context, a "percussion parameter" is to be understood as meaning, in particular, a value of an operating parameter influencing the operation of the percussion mechanism, In particular, the percussion parameter may be a pressure and / or a percussion speed and / or a percussion frequency. The control unit can take into account the hammer mechanism parameter determined during operation of the percussion mechanism, and the operation of the percussion mechanism can be particularly reliable.

The impact mechanism can be operated with high efficiency under different operating conditions.

It is proposed that the operating condition sensor unit is intended to detect at least one temperature. In particular, the operating condition sensor unit may be provided to detect a temperature of a percussion environment. In particular, the operating condition sensor unit may be provided to detect a temperature of the percussion mechanism. In this context, a "temperature of the percussion mechanism" is to be understood in particular to mean a temperature of a component of the percussion mechanism, in particular the guide tube and / or the racket and / or a striking mechanism and / or gearbox housing The temperature may expand components and change tolerances between components The performance of the percussion mechanism may change The control unit may set particularly suitable operating parameters for the temperature.

It is further proposed that the operating condition sensor unit is provided to detect at least one ambient air pressure. The environment In particular, air pressure can influence a start-up behavior of the percussion mechanism and / or a return movement counter to the impact direction of the racket. In particular, a return movement of the racket at low ambient air pressure can be unreliable. In particular, starting up the beater unit at low ambient air pressure can be unreliable. By "unreliable" is meant in this context in particular that the impact operation repeatedly and / or arbitrarily fails, in particular at least every 5 minutes, preferably at least every minute and / or that a start of the percussion at more than every tenth attempt to start the percussion The control unit may set suitable ambient air pressure operating parameters to ensure reliable operation.

It is further proposed that the control unit be provided to determine at least one limit frequency of an amplitude frequency response of the percussion mechanism. In this context, an "amplitude frequency response" of the percussion mechanism is to be understood as meaning, in particular, an impact strength of the striker as a function of a percussion frequency and / or percussion speed one

Piston of percussion moved. The piston may in particular be provided to generate a pressure pad to pressurize the racket. The racket can be moved in particular by the pressure pad generated by the piston with the beat frequency. The beat frequency and percussion speed are preferably directly related.

In particular, the amount of beat frequency 1 / s may be the amount of hammer speed U / s. This is the case when the bat performs one stroke per revolution of the eccentric gear. As a result, the terms "frequency" and "speed" are therefore equivalently used. The person skilled in the art will adapt the following explanations correspondingly to deviations of a percussion mechanism from this context. In this context, a "cutoff frequency" should be understood as meaning, in particular, a frequency in which a behavior of the amplitude frequency response fundamentally changes.The cutoff frequency can represent a transition between a continuous and a discontinuous range of the amplitude frequency response Represent the beginning of a frequency range by the amplitude-frequency response has a hysteresis and / or in that a plurality of possible amplitudes are assigned to one frequency. Operation of the percussion mechanism may be unreliable and / or inadmissible at certain frequencies. The cutoff frequency may specify a beginning or an end of such a range. It can be avoided that the impact mechanism is operated with unreliable and / or impermissible operating parameters. A reliability of the impact mechanism can be increased. A performance of the impact mechanism can be increased. It is further proposed that the control unit is provided to set at least one operating parameter of the striking mechanism. Preferably, the control unit is provided to set the operating parameters depending on a determined percussion parameters. In particular, the control unit may be provided to set a starting value for the operating parameter. Further, the control unit may be provided to set a working value and / or a minimum and / or maximum working value for the operating parameter. Further, the control unit may be provided to set an idle value for the operating parameter. In this context, a "work value" is understood to mean a value of the operating parameter set by the control unit in the impact operation of the percussion mechanism.

In this context, an "idling value" is understood to mean a value of the operating parameter set by the control unit during idle operation of the percussion mechanism. "Start value" in this context is a value of the operating parameter set by the control unit when the percussion mechanism changes from idling operation be understood in the impact mode. In this context, an "idling operation" is to be understood as meaning, in particular, an operating state of the percussion mechanism which is characterized by the absence of regular impact pulses The striking mechanism may preferably have an idling mode in which it is intended for idling operation In this context, in particular, an operating state of the percussion mechanism can be understood, in which the Schlagwerk preferably applies regular impact impulses. Preferably, the percussion mechanism may have a percussion mode in which it is intended for percussion operation. In this context, "regular" should be understood in particular as recurring, in particular with a designated frequency In this context, in particular a mode and / or a setting of the control unit are understood. The operating state may be dependent in particular on user settings, environmental conditions and other parameters of the striking mechanism. In this context, a "change" from the idling mode to the striking mode should be understood to mean starting the percussion unit from the idling mode The changeover into the striking mode can take place, in particular, when the striking mechanism is switched over from the idling mode to the striking mode In particular, the control unit may set the operating parameters depending on the operating conditions, in particular on a temperature and / or an ambient air pressure The impact mechanism may be operated under advantageous operating parameters under different operating conditions Particularly robust is the low-ambient-pressure drumming process, where operating parameters can be set at high ambient air pressure where the impact mechanism is particularly powerful Stability reserve of the operating parameters can be low. In this context, a "robustness reserve" is to be understood as meaning, in particular, an adjustment of an operating parameter which is intended to ensure reliable operation under deviating operating conditions and results in reduced performance under given operating conditions. that the percussion mechanism safely starts at a beat frequency of 20 - 70 Hz at least at an ambient air pressure of 950 - 1050 mbar and an ambient temperature of 10 - 30 ° C and / or a beat frequency of 20 - 70 Hz can be used as start value safe operating parameters for the operation of the percussion mechanism can be defined, sensors for monitoring the operation of the percussion mechanism can be dispensed with and failure of a percussion operation can be unlikely.

It is proposed that the operating parameter is a throttle characteristic of a venting unit. In this context, a "throttle characteristic" is to be understood as meaning, in particular, a setting of the venting unit which alters a flow resistance of the venting unit, in particular a flow cross-section. sem context in particular a loading and / or ventilation unit of the striking mechanism are understood. The venting unit can be provided in particular for a pressure and / or volume compensation of at least one room in the striking mechanism. In particular, the venting unit may be provided for venting and / or venting a space in a guide tube guiding the racket in the direction of impact in front of and / or behind the racket. Preferably, the operating parameter may be a throttling position of the venting unit of the space arranged in the direction of impact in front of the racket. If the flow cross-section of this venting unit is increased, the venting of the space in front of the beater can be improved. A counterpressure against the direction of impact of the racket can be reduced. The impact strength can be increased. If the flow cross-section is reduced in this vent unit, the ventilation of the space in front of the racket can be reduced. A back pressure opposite to the direction of impact of the racket can be increased. The impact strength can be reduced. In particular, the return movement of the racket against the direction of impact can be supported by the back pressure. The start of the impact mechanism can be supported. The operating parameter can ensure a reliable starting of the impact mechanism. The operating parameter with reduced flow area may be a stable operating parameter. It can be suitable as start value. The operating parameter with increased flow cross section may be a critical operating parameter with increased hammer performance. It can be suitable as a labor value. In an advantageous embodiment of the invention it is proposed that the

Operating parameter is the beat frequency and / or a percussion speed. The striking mechanism speed can be set particularly easily by the control unit. A percussion speed can be particularly suitable for a machining case. The striking mechanism can be particularly powerful at a high percussion speed. The percussion engine can be operated at a higher percussion speed at a higher speed. A fan driven by the engine can also operate at a higher speed. Cooling of the hammer mechanism and / or the motor by the ventilation unit can be improved. A function of an impact amplitude of the percussion mechanism can be dependent on the percussion speed. At a speed above a limit speed, the function can hysterise exhibit and be ambiguous. A start of the beat operation when switching from the idle mode to the beat mode and / or a restart of the beat operation at a stop of the beat operation may be unreliable and / or impossible. A percussion speed below the limit speed can be used as a starting value and / or labor value for a stable impact operation.

A percussion speed above the limit speed can be used as a work value for a critical impact operation. Above a maximum speed, impact operation may be impossible and / or unreliable. In this context, "unreliable" is to be understood in particular as meaning that the impact operation is repeated and / or arbitrary, in particular at least every 5 minutes, preferably at least every minute The impact mechanism can also be particularly efficient with this operating parameter The control unit can also be designed to determine a limiting speed, a starting speed and / or a maximum speed.

It is further proposed that the control unit is provided to determine the at least one operating parameter with the aid of a computing unit. In this context, a "computing unit" is to be understood as meaning in particular a unit for calculating at least one mathematical formula A "formula" in this context is to be understood in particular as an arithmetic rule which is intended to calculate the operating parameter as a function of input variables to investigate. In particular, the formula may be provided to calculate a cutoff frequency as a function of an ambient air pressure and / or a temperature. A suitable formula can be determined by the skilled person on the basis of calculations and / or on the basis of tests. A formula can be an approximation to a real behavior of the impact mechanism. The person skilled in the art will determine which deviations are a suitable formula from the real one, for example in

Trying to behave may have behaviors. In particular, a formula may be suitable if a calculated value differs by less than 50%, preferably by less than 25%, particularly preferably by less than 10%, from a value determined in tests with the striking mechanism. The control unit can calculate a limit parameter for an operating value, above which a

Schlagwerk start is unreliable. The control unit can now be an outgoing from the limit parameter by a margin of safety reduced operating parameters as the starting value for this operating value. The control unit can determine the operating parameters particularly easily. It is further proposed that the control unit is provided to determine the at least one operating parameter with the aid of a memory unit for storing a characteristic curve and / or a characteristic map. In this context, a "characteristic curve" is to be understood as meaning a number of value pairs which link a value to a further value of the value pair.A "characteristic field" is to be understood in this context as meaning a number of characteristic curves each having a plurality of specified values link a further, variable value, wherein the individual characteristics differ in the amounts of at least one of the specified values. The characteristic curves and / or the characteristic diagrams can be determined in experiments and / or by calculations. The control unit can determine an operating parameter by taking from the characteristic curve and / or the characteristic field the values which match the measured operating conditions. The control unit may advantageously be provided to suitably interpolate values between the values detected in the characteristic curve and / or the characteristic map. A variety of methods are known to those skilled in the art, as an interpolation of values is possible. The control unit can determine the operating parameters with a particularly low computational effort. The values can be determined by tests. A linking of the values by a function equation can be omitted. It is further proposed that the control unit be provided to take into account location information and / or an operating mode and / or a use case in the determination of the at least one striking mechanism parameter and / or of the at least one operating parameter. In this context, "positional information" is to be understood as meaning, in particular, a direction of a weight force with respect to the impact mechanism The control unit may set operating parameters in dependence on the position

Schlagwerkstart be increased when the work situation is essentially down is directed. An initial value of the beat frequency for the percussion start can be lowered if the working position is directed substantially upwards. In this context, a "working position" is to be understood as meaning, in particular, an orientation of the percussion mechanism with respect to the force of gravity

In principle, a "use case" in this context is to be understood as meaning in particular a specific application in which particular operating parameters are advantageous. An application may require a particularly low-vibration operation, a particularly high impact and / or a certain frequency or a particularly fast and / or frequent Schlagwerkstart. The control unit may set operating parameters depending on the application. In particular, a "mode of operation" may be a chisel operation, a hammer action with deactivated impactor or a percussion drill with activated percussion and a rotating drilling motion.The control unit may set operating parameters depending on the operating mode, and at least one other sensor may be provided at one speed The control unit can be designed to set or regulate at least one operating parameter depending on the determined impact strength It is further proposed that the control unit be provided to take into account at least one wear parameter in the determination of the at least one striking mechanism parameter and / or of the at least one operating parameter In particular, a wear amount of carbon brushes of the engine and / or a varying friction can be used. The control unit may be provided to estimate the wear parameter based on an operating hours counter. The control unit may include maps and / or functions of operating parameters depending on a state of wear and / or on a number of operating hours. The control unit may have sensors which are provided to measure a wear parameter, in particular a wear amount of carbon brushes. The control unit can set operating parameters depending on the wear parameters.

It is proposed that the control unit is provided, in at least one operating state, for a change from the idling mode to the

Impact mode to temporarily lower the beat frequency and / or percussion speed to a start frequency and / or a starting speed. In this context, a "starting frequency and / or a starting rpm" is to be understood as meaning, in particular, a rotational speed below the limiting rotational speed which is suitable for a reliable change from the idling mode to the hammering mode In particular, the idling speed in the idling mode can be identical to a working speed in the impact mode if the working speed is a stable operating parameter of the impact mechanism.

It is further proposed that the control unit be provided to set the operating parameter directly to the work value in at least one operating state for a change from idle operation to impact operation. In particular, the control unit may be provided to set the operating parameter directly to the work value when a user requests a work value which, under given conditions, is a stable operating parameter. A change from the idle mode to the beat mode can be reliable with this work value. Setting the start value can be avoided. An irritation of the user by a brief change of the operating parameter to start the percussion can be avoided. An intervention of the control unit in the operating parameters can be omitted.

Furthermore, an operation change sensor is proposed, which is intended to signal a change of the operating mode. In particular, the operating change sensor of the control unit can signal a change from the idle mode to the beat mode. The operation change sensor can be provided to detect a contact pressure of the tool on a workpiece. It can be recognized advantageous when the user begins a machining operation. Particularly advantageously, the change-of-operation sensor can detect a switching over of the percussion mechanism, in particular an opening and / or closing of idling openings and further openings of the percussion mechanism, which are provided for a change of operating mode. The operation change sensor can be a

Detecting displacement of a control sleeve, which is provided for the operating mode change of the striking mechanism. The control unit can advantageously detect when the operating mode change of the impact mechanism takes place. The control unit may advantageously change the operating parameter to the

To support and / or facilitate operating mode changes. The impact mode can be reliably started.

It is further proposed that the control unit has at least one delay parameter which is intended to influence a time duration for a change between two values of the operating parameter. Of the

Change from an idle value and / or work value to a start value and / or from the start value to the work value can be done by a setpoint jump. Preferably, the change can be linear and / or have a steady course. A current consumption of the motor can be limited. Accelerations, driving forces and / or vibrations can be reduced. The delay parameter may be provided to specify a slope of the function defining the change between the operating parameters. In particular, the time period for the start of the percussion can be set. In this context, a "start-up" should be understood to mean, in particular, a start of the impact mode from a standstill of the engine The start-up of the impact mechanism can take place from standstill directly to a critical working value, in particular a critical working speed Start the impact mechanism before the limit speed is reached The control unit can allow a striking mechanism start with a critical working frequency from standstill if the speed increases slowly

Start value can be waived. If the speed increases rapidly, a striking mechanism start can not start before reaching the limit speed. The speed must be temporarily set to the start speed for a percussion start. Optimum operation of the impact mechanism can be ensured. Furthermore, a hand-held power tool with a percussion unit with the mentioned properties is proposed. The hand tool may have the advantages mentioned.

Furthermore, a control unit for determining an operating parameter of a percussion unit with the mentioned properties is proposed. The control unit can have the stated advantages.

Furthermore, a method for determining an operating parameter of a percussion unit is proposed. The method can have the stated advantages.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, three embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 is a schematic representation of a hammer and percussion hammer with a percussion unit according to the invention in a first embodiment in an idle mode,

2 shows a schematic representation of the hammer and percussion hammer in a striking mode,

3 is a schematic representation of a simulated amplitude frequency response of a non-linear oscillatory system,

4 is a schematic representation of another simulated amplitude frequency response of the non-linear oscillatory system, Fig. 5 is a schematic representation of a simulated impact energy of

Percussion unit at a percussion start at falling and at rising beat frequency,

6 shows a schematic representation of a possible definition of a start value, a limit value, a work value and a maximum value,

Fig. 7 is a schematic representation of the simulated impact energy of

Impact unit at a percussion start at different ambient air pressure conditions,

8 is a block diagram of an algorithm of the percussion unit,

9 is a linear characteristic diagram of an impact mechanism with a striking mechanism unit in a second embodiment,

10 is a bilinear map,

Fig. 1 1 is a schematic representation of a venting unit of a hammer mechanism of a hammer and percussion hammer with a percussion unit in a third embodiment and

Fig. 12 is a further schematic representation of the ventilation unit.

Description of the embodiments

Figure 1 and Figure 2 show a drill and percussion hammer 12a with a percussion unit 10a and with a control unit 14a, which is intended to control a pneumatic percussion 16a and regulate. The percussion unit 10a includes a motor 36a with a gear unit 38a, which rotatably drives a hammer tube 42a via a first toothed wheel 40a and drives an eccentric gear 46a via a second toothed wheel 44a. The hammer tube 42a is rotatably connected to a tool holder 48a, in which a tool 50a can be clamped. The tool holder 48a and the tool 50a may be driven for a drilling operation via the hammer tube 42a with a rotating working motion 52a. When a beater 54a is accelerated in an impact direction 56a in the direction of the tool holder 48a in an impact mode, it will impart a bounce impulse to the tool 50a upon impact with a striker 58a disposed between the beater 54a and the tool 50a , The tool 50a exerts a beating working movement 60a by the impact pulse. A piston 62a is also movable in the hammer tube 42a on which the beater direction 56a opposite side of the racket 54a stored. The piston 62a can be moved periodically in the hammer tube 42a in the direction of impact 56a and back again via a connecting rod 64a of the striking gear speed driven eccentric gear 46a. The piston 62a compresses an air cushion 66a sandwiched between the piston 62a and the beater 54a in the hammer tube 42a.

Upon movement of the piston 62a in the direction of impact 56a, the racket 54a is accelerated in the direction of impact 56a. By a rebound on the firing pin 58a and / or by a by a return movement of the piston 62a against the direction of impact 56a between the piston 62a and the racket 54a resulting negative pressure and / or by a back pressure in a striking space 100a between the racket 54a and the firing pin 58a the racket 54a are again moved back against the direction of impact 56a and then accelerated again in the direction of impact 56a for a next impact pulse. In a region between the racket 54a and the striker 58a, vent holes 68a are arranged in the hammer pipe 42a, so that the air blown space 100a can escape between the racket 54a and the striker 58a. In an area between the racket 54a and the piston 62a, idling openings 70a are arranged in the hammer pipe 42a. The tool holder 48a is slidably mounted in the direction of impact 56a and is supported on a control sleeve 72a. A spring element 74a exerts a force on the control sleeve 72a in the direction of impact 56a. In a striking mode 76a, in which the tool 50a is pressed against a workpiece by a user, the tool holder 48a, against the force of the spring element 74a, displaces the control sleeve 72a to cover the idling openings 70a. If the tool 50 a set off from the workpiece, the

Tool holder 48a and the control sleeve 72a in an idle mode 80a by the spring member 74a so shifted in the direction of impact 56a that the control sleeve 72a, the idle openings 70a releases. A pressure in the air cushion 66a between piston 62a and racket 54a can escape through the idling openings 70a. The racket 54a is not in the idle mode 80a, or only slightly by the

Air cushion 66a accelerates (Figure 1). In idle mode, the racket 54a exerts no or only small impact pulses on the firing pin 58a. The hammer and percussion hammer 12a has a hand tool housing 82a with a handle 84a and an additional handle 86a, where it is guided by the user. Onset of a striking operation upon switching of the percussion unit 10a from the idle mode 80a to the striking mode 76a by closing the idling openings 70a depends on percussion parameters, in particular percussion speed and ambient air pressure. Piston 62a experiences a periodic excitation with a beat frequency corresponding to the hammer speed of eccentric gear 46a, due to the air cushion 66a trapped between piston 62a and racket 54a. The percussion mechanism 16a represents a nonlinear oscillatory system. FIG. 3 shows a schematic representation of a simulated amplitude frequency response of a general, non-linear oscillatory system as a function of a frequency f. The amplitude A corresponds to the amplitude of a non-illustrated, the racket 54 a corresponding oscillating body of the system at an external excitation, as in the

Schlagwerk 16a is carried by the piston 62a. The amplitude frequency response is nonlinear; at high frequencies, the amplitude frequency response has several solutions. Which amplitude is set in this range depends inter alia on the direction in which the frequency f is changed. If, starting from a higher frequency f, a minimum frequency 124a of the range of the amplitude frequency response with multiple solutions is undershot, the amplitude A jumps from an infinite pitch vertex 126a to an admissible solution of the amplitude frequency response with a higher level. If a maximum frequency 128a of the range of the amplitude frequency response with a plurality of solutions is exceeded from a lower frequency f, then the

Amplitude A from an infinite pitch vertex 130a to an allowable solution of the amplitude frequency response at a lower level. In the figure 3, this behavior is indicated by arrows. FIG. 4 shows a further simulated amplitude-frequency response of the non-linear oscillatory system under different conditions. The amplitude frequency response has a gap 132a instead of a maximum frequency 128a. This case occurs, for example, when the maximum frequency 128a is higher than a possible excitation frequency with which the oscillatory system can be excited. In the case of percussion mechanism 16a, for example, the excitation frequency may be limited by a maximum speed of eccentric gear 46a. The effect of the non-linear amplitude frequency response on the impact mode of the percussion mechanism 16a is shown in FIG. FIG. 5 shows a simulated impact energy E of the percussion mechanism 16a for a percussion start with falling beat frequency 92a and with increasing beat frequency 94a. Will the bat

54a is excited with an increasing striking mechanism speed or beat frequency 94a, the striking energy E increases with increasing beat frequency 94a. If the club 66a is excited from an idle mode from a high striking mechanism speed with a falling striking mechanism speed or beat frequency 92a, the beat operation only starts at a certain speed Impact speed. This percussion speed represents a cutoff frequency 20a. Above this beat frequency, the racket 54a does not begin to move or only to move at a low amplitude and / or speed when the beat rate 92a is falling, even when switching from the idle mode 80a (FIG. 1) to the beat mode 76a (Figure 2), the idling openings 70a are closed. There are no or very little impact pulses exerted by the racket 54a on the firing pin 58a. Above a maximum value 90a, the impact energy E falls steeply. The racket 54a in this case performs no movement in the direction of impact 56a or movements with a small amplitude in the direction of impact 56a, so that no or only small impact pulses with a low impact energy E are delivered to the firing pin 58a. Depending on environmental conditions and the design of the percussion mechanism 16a, the cutoff frequency 20a is in a range of 20-70 Hz. The maximum value 90a is greater than the cutoff frequency 20a and lies within a range of 40-400 Hz depending on ambient conditions and the design of the impact mechanism 16a Depending on the ambient conditions and the design of the percussion mechanism 16a, the impact energy E reaches 1 to 200 joules at the cutoff frequency 20a and 2 to 400 joules at the maximum value of 90a. FIG. 6 shows a schematic representation of a possible definition of operating parameters, in particular of a start value 28a, the limit frequency 20a, a working value 30a and the maximum value 90a. The cut-off frequency 20a is preferably selected at a percussion speed n at which the amplitude frequency response has a clear solution and a reliable percussion start is possible. The starting value 28a is less than or equal to the cutoff frequency 20a. A safe Schlagwerkstart can be guaranteed, regardless of which direction the starting value 28a is approached. The cut-off frequency 20a represents the transition to an ambiguous amplitude frequency response and the maximum starting value 28a. The starting value 28a is preferably selected at a distance from the cut-off frequency 20a, for example with a reduction of 10%

Percussion speed. If the impact operation is ensured, the percussion mechanism 16a can be operated with a higher power at a supercritical work value 30a. A safe Schlagwerkstart is not guaranteed in the supercritical work value 30a. Above the maximum value 90a, the impact energy E drops sharply. The work value 30a is therefore chosen lower than the maximum value 90a. The labor value 30a can be set by the control unit 14a or set by the user, for example via a selector switch not shown here. The working values 30a are determined, inter alia, depending on a processing case and / or a type of material and / or a type of tool. Various adjustable operations are labor values

30a assigned. A work value 30a above the cutoff frequency 20a is a supercritical work value 30a, a work value 30a below the cutoff frequency 20a and / or below the start value 28a is a stable work value 30a. In addition to the starting value 28a and the limit frequency 20a, an idling value 140a can optionally be defined. The idle value 140a is set in idle mode 80a, in particular. The idling value 140a is advantageously set higher than the starting value 28a. A ventilation unit, not shown here, driven by the motor 36a can then be operated at a higher speed than when operating with the starting value 28a. The cooling of percussion mechanism 16a in idle mode 80a improves. An operating noise of the drilling and

Schlaghammer's 12a is perceived by the user as more powerful than the starting value of 28a. Further, the idle value 140a is advantageously set lower than the work value 30a. Noise emissions and / or vibrations may be reduced compared to operation with the work value 30a. When changing from the idle mode 80a to the beat mode 76a, the starting value 28a may be reached faster than the work value 30a.

FIG. 7 shows the simulated impact energies E of the percussion mechanism 16a in the case of a percussion start with falling and with rising beat frequency under different ambient conditions. In this example, the curve 134a shows the Impact energy E at a first ambient air pressure and the curve 136a the impact energy E at a second, compared to the first ambient air pressure reduced ambient air pressure. A cutoff frequency 138a at the second ambient air pressure occurs at a lower beat frequency than the cutoff frequency 20a at the first ambient air pressure. If the second ambient air pressure is 10% lower than the first ambient air pressure, the cutoff frequency 138a is 1-25% lower than the first ambient air pressure, depending on further influencing factors. A temperature of the percussion mechanism 16a, in particular of the hammer tube 42a, also has an influence on the cutoff frequency 20a. At a lower ambient temperature, a friction of the racket 54a in the hammer tube 42a increases, in particular by an increasing viscosity of

Lubricants. If the temperature of the hammer tube 42a decreases by 10K, the cut-off frequency 20a is reduced by 1 - 30% depending on further influencing factors. The cut-off frequency 20a can also change by +/- 20% due to tool influences. The tool can influence a rebound of the

Stick 54a of the firing pin 58a have and thus affect the cutoff frequency 20a of the beat frequency.

The control unit 14a is provided to determine the impact mechanism parameters as a function of measured values of an operating condition sensor unit 18a. In particular, the control unit 14a is provided to determine the cutoff frequency 20a of the amplitude frequency response for a reliable percussion start. The operating condition sensor unit 18a is provided to detect a temperature and the ambient air pressure. The operating condition sensor unit 18a is integrated as a module on a circuit board of the control unit 14a. The operating condition sensor unit 18a detects an ambient temperature. The temperature has an influence on a viscosity of lubricants and on a friction of the racket 54a with the hammer tube 42a. The ambient air pressure in particular has an influence on the return movement of the racket 54a and on the limit frequency 20a of the amplitude frequency response for a reliable percussion start. In addition, the Betriebsbedingungssensor- unit 18a via a wireless interface not shown here, by means of which they can relate temperature and ambient air pressure data from an external device also not shown here, such as a smartphone and / or from the Internet. The control unit 14a is further intended to set operating parameters of the hammer mechanism 16a. The operating parameter is to be determined with the aid of a computing unit 24a for calculating a formula. One possible formula for determining a pressure-dependent maximum value 90a of the target percussion speed as a function of the ambient air pressure is:

fsoll.max ⁼ f 0 ⁺ C | j _n , p * P

fo represents a base frequency and / or base speed, C | _{in, p} an application-dependent constant of the pressure term and P the ambient air pressure. In the present example, f _{0 has} the value of 10 Hz and C | _{in, p} a value of 0.05 Hz / mbar. At an ambient air pressure of 1000mbar, f _is n _{, max} 60 Hz. The person skilled in the art will suitably adapt these parameters. Correspondingly, pressure-dependent values for the starting value 28a, the working value 30a and the limit frequency 20a can be defined for deviating basic rotational speeds and / or deviating pressure- and application-dependent constants C i _in , _p . If the working value 30a and / or the maximum value 90a of the set percussion speed is set below the cutoff frequency 20a, the starting value 28a can be dispensed with and the striking mechanism 16a can be started with the work value 30a.

The control unit 14a can take into account the temperature in an operating mode in addition to the ambient air pressure, the functional equation is extended in this case as follows:

fsoll.max = f 0 ⁺ C | i _n , p * P + C | i _n , T *

C Νη _, τ represents an application-dependent constant of the temperature term. The other operating parameters are determined analogously. In the present example, f _{0 has} the value of 5 Hz, C | _{in, p} a value of 0.05 Hz / mbar and C | _in , T a value of 0.25 Hz / ° C where the temperature in ° C is to be used. At an ambient air pressure of 1000 mbar and a temperature of 20 ° C is f _SO ii, max 60 Hz. The skilled artisan will suitably adjust these parameters.

In addition to ambient air pressure and temperature, other terms may be introduced, such as an operating hours-dependent term that takes into account a change in percussion due to wear. A position sensor (not shown here) of the operating condition sensor unit 18a detects a position of the hammer and percussion hammer 12a; the position information can be taken into account in a further term in the definition of the operating parameters. The term for the working position is chosen such that f _S oii, max is reduced in the case of an upward working position and in the case of a downward working position. ge is increased. Suitable factors for this term may be determined by one skilled in the art in experiments.

In a further operating mode, the user can set a rotational speed factor (Xüreh) 88a via a rotary knob (not shown here in detail), which is then set with a pressure-dependent and / or temperature-dependent target stroke rate for the impact mode fsoii.max in u Iti pl ϊζίβΓΐ:

fsoll ⁼ Xüreh * fsoll, max

The rotational speed f _so n is set by the control unit 14a in impact mode. The user can thus lower the percussion speed as desired on the basis of the optimum operating value 30a for the respective operating conditions.

FIG. 8 shows a block diagram of an algorithm of percussion unit 10a. Depending on ambient air pressure P and temperature T, in a first step 142a the maximum value 90a of the target impact number is determined. The speed factor 88a is multiplied by the maximum value 90a in a second step 144a in order to determine the operating value 30a of the target speed. A control unit 96a controls the motor 36a by means of power electronics 146a. A translation of the gear unit 38a is taken into account in the determination of a required speed for a target speed of the motor 36a by the percussion unit 10a. From the motor 36a, the control unit 96a becomes an actual speed value

148a returned to the control of the motor 36a.

When a supercritical work value 30a is selected as a target beat number, the control unit 14a is provided to temporarily set the target beat number to the start value 28a for a change from the idle mode to the beat mode. After a fixed period of time, in which a percussion start has taken place during operation of the percussion mechanism 16a with the starting value 28a, the target number of strokes is increased to the working value 30a. The period of time during which the percussion mechanism unit 10a sets the start value 28a in the case of a percussion start is determined by a delay parameter. The delay parameter is determined by a person skilled in the art or advantageously adjustable by the user.

An operation change sensor 32a is provided to signal the percussion unit 10a to change the operation mode. The change of business The sensor 32a is arranged to detect and signal a control sleeve position when the control sleeve 72a is shifted from the idle mode 80a to the striking mode 76a. The percussion unit 10a now temporarily sets the target beat number to the start value 28a if a supercritical work value 30a has been selected.

The following description and the drawings of further embodiments are essentially limited to the differences between the exemplary embodiments, with respect to identically named components, in particular with respect to components having the same reference numerals, basically also to the

Drawings and / or the description of the other embodiments may be referenced. To distinguish the embodiments, instead of the letter a of the first embodiment, the letters b and c the reference numerals of the other embodiments followed.

FIG. 9 and FIG. 10 show a characteristic curve and a characteristic diagram of a hammer mechanism unit in a further exemplary embodiment. The percussion unit of the second embodiment differs from the previous one in that an operating parameter is determined with the aid of a memory unit for storing a characteristic curve and a characteristic diagram. The characteristic curve (FIG. 9) and the characteristic diagram (FIG. 10) serve, as described, to determine a maximum value 90b of a target impact rate f _SO ii, max. The characteristic defines the maximum value 90b as a function of an ambient air pressure P; the map is used to determine the maximum value 90b depending on the ambient air pressure P and a temperature T. Intermediate values of the map are interpolated suitably by the percussion unit.

FIG. 11 and FIG. 12 show a striking mechanism unit 10c in a further exemplary embodiment. The percussion unit 10c differs from the previous percussion unit in that an operating parameter set by a control unit 14c is a throttle characteristic of a vent unit 22c. A striking space in a hammer tube 42c is limited by a striker and a club. The venting unit 22c has in the hammer tube 42c ventilation openings for venting the striking space. The venting unit 22c serves to equalize the pressure of the striking space with an environment a striking mechanism 16c. The venting unit 22c has an adjusting unit 102c. The setting unit 102c is designed to influence a venting of the striking space 56c in front of the racket during a striking operation. The hammer tube 42c of the striking mechanism 16c is mounted in a gear housing 104c of a hammer and percussion hammer 12c.

The gear housing 104c has radially arranged ribs 106c facing an outer side of the hammer tube 42c. Between the hammer tube 42c and the gear housing 104c, a bearing bush 108c, which supports the hammer tube 42c on the gear housing 104c, is pressed into an end region 1c facing an eccentric gear. The bushing 108c forms with the ribs 106c of the gear housing 104c air channels 1 12c, which communicate with the vents in the hammer tube 42c. The air ducts 1 12c form part of the venting unit 22c. The striking space is connected via the air ducts 1 12 c with a gear chamber 1 14 c arranged behind the hammer pipe 42 c against the direction of impact 56 c. The air channels 1 12c form throttling points 1 16c, which influence a flow cross section of the connection of the striking space with the gear chamber 1 14c. The adjusting unit 102c is provided to adjust the flow area of the throttling points 16c. The air channels 1 12c forming the throttle points 1 16c form a transition between the striking space and the gear chamber 1 14c. An adjustment ring 149c has star-shaped, inwardly directed valve extensions 120c. Depending on a rotational position of the adjusting ring 149c, the valve extensions 120c may completely or partially cover the air ducts 12c. By adjusting the adjusting ring 149c, the flow cross section can be adjusted. The control unit 14c adjusts the adjusting ring 149c of the adjusting unit 102c by rotating the adjusting ring 149c by means of a servo drive 122c. If the venting unit 22c is partially closed, the pressure in the striking area resulting from a movement of the striker in the striking direction 56c can escape only slowly. A backpressure directed against the movement of the racket in the direction of impact 56c is formed. This back pressure supports a return movement of the

Bat against the direction of impact 56c and thus a percussion start. If a supercritical work value is selected for the percussion speed at which no reliable impact mechanism start is possible when the ventilation unit 22c is open, the control unit 14c partially closes the ventilation unit 22c for a change from an idling operation to an impact operation. By the back pressure in the batting room the start of the beat operation is supported. After completion of Schlagwerk start the control unit 14c opens the vent unit 22c again. The control unit 14c may also use the operating parameter of the throttle characteristic of the venting unit 22c for power regulation.

Claims

claims

1 . Impactor unit, in particular for a drilling and / or percussion hammer (12a, 12c), with a control unit (14a, 14c), which is intended to control and / or regulate a pneumatic impact mechanism (16a, 16c), and at least one Operating condition sensor unit (18a), characterized in that the control unit (14a, 14c) is provided to determine at least one striking mechanism parameter as a function of measured values of the operating condition sensor unit (18a).

2. percussion unit according to claim 1, characterized in that the

Operating condition sensor unit (18a) is provided to detect at least one temperature.

3. percussion unit according to claim 1 or 2, characterized in that the operating condition sensor unit (18 a) is provided to detect at least one ambient air pressure.

4. percussion unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) is provided to determine at least one cutoff frequency (20a) of an amplitude frequency response of the striking mechanism (16a, 16c).

5. percussion unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) is provided to set at least one operating parameter of the striking mechanism (16a, 16c).

6. percussion unit according to claim 5, characterized in that the

Operating parameter is a throttle characteristic of a vent unit (22c).

7. percussion unit at least according to claim 5, characterized in that the operating parameter is a beat frequency and / or a percussion speed.

8. percussion unit at least according to claim 5, characterized in that the control unit (14a, c) is provided to determine the at least one operating parameter by means of a computing unit (24a).

9. percussion unit at least according to claim 5, characterized in that the control unit (14a, 14c) is provided to determine the at least one operating parameter with the aid of a memory unit for storing a characteristic curve and / or a characteristic field.

10. percussion unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) is provided to take into account location information and / or an operating mode and / or a use case in the determination of the at least one percussion parameter and / or at least one operating parameter ,

1 1. Impact unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) is provided to take into account at least one wear parameter in the determination of the at least one striking mechanism parameter and / or at least one operating parameter.

12. percussion unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) is provided for temporarily setting at least one operating parameter to a starting value (28a) in at least one operating state for a change from an idling operation to a percussion operation.

13. impact mechanism unit at least according to claim 5, characterized in that the control unit (14a, 14c) is provided to adjust the operating parameters to a supercritical work value (30a) in at least one operating state in impact mode.

14. percussion unit at least according to claim 5, characterized in that the control unit (14a, 14c) is provided to set the operating parameter directly to the work value (30a) in at least one operating state to a change from the idle mode to the percussion mode.

15. percussion unit according to one of the preceding claims, characterized by an operating change sensor (32 a), which is intended to signal a change of the operating mode.

16. Impact unit according to one of the preceding claims, characterized in that the control unit (14a, 14c) has at least one delay parameter, which is intended to influence a period of time for a change between two values of the operating parameter.

17. Hand tool, in particular drilling and / or percussion hammer (12a;

12c), with a percussion unit (10a, 10c) according to one of the preceding claims.

18. Control unit of a hammer mechanism unit (10a, 10c) for determining an operating parameter of the hammer mechanism unit (10a, 10c) according to one of claims 1 - 16.

19. A method for determining an operating parameter of a percussion unit (10a, 10c) with a control unit (14a, 14c) according to one of claims 1-16.