EP2921263A1 - Reconnaissance de comportement au choc en fonction de la charge - Google Patents

Reconnaissance de comportement au choc en fonction de la charge Download PDF

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Publication number
EP2921263A1
EP2921263A1 EP14160201.1A EP14160201A EP2921263A1 EP 2921263 A1 EP2921263 A1 EP 2921263A1 EP 14160201 A EP14160201 A EP 14160201A EP 2921263 A1 EP2921263 A1 EP 2921263A1
Authority
EP
European Patent Office
Prior art keywords
motor current
rotor
tangential
value
drive shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP14160201.1A
Other languages
German (de)
English (en)
Inventor
Alexander Funk
Sören Schöpke
Hans-Dieter Gaul
Benedikt Beckert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hilti AG
Original Assignee
Hilti AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hilti AG filed Critical Hilti AG
Priority to EP14160201.1A priority Critical patent/EP2921263A1/fr
Publication of EP2921263A1 publication Critical patent/EP2921263A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • B25B21/02—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose with means for imparting impact to screwdriver blade or nut socket
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
    • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
    • B25B23/147—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers
    • B25B23/1475—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers for impact wrenches or screwdrivers

Definitions

  • the present invention relates to a method of controlling a machine tool including an electric motor, a controller, and a tangential impactor.
  • the machine tool can be, for example, a tangential impact driver or an impact wrench with a tangential impact mechanism.
  • a tangential impact wrench periodically provides, for a short time, a large tightening torque for tightening screw connections or for setting screw anchors.
  • a continuous lower torque is delivered, which must counteract the user or a stand.
  • the tangential impact wrench is suitable for use in a variety of materials of varying hardness, for example in stone, concrete, brick, sand-lime brick, aerated concrete or the like.
  • a Tangential impact wrench according to the prior art, for example, in the German patent application DE 10 2009 002 479 shown.
  • a tangential impact driver is shown in which a tool holder is driven by an output shaft.
  • a motor drives a drive shaft
  • the drive shaft is permanently rotated about a longitudinal axis in one direction of rotation.
  • the speed of the motor is controlled by a motor control.
  • a striking mechanism couples the drive shaft with the output shaft.
  • the drive shaft can thereby transmit its torque continuously to the output shaft or a torque of the drive shaft serves to wind a buffer which transmits a higher torque to the output shaft in periodic beats.
  • the object of the present invention is to solve this problem described above and to provide a method for controlling a machine tool, in particular a tangential impact driver, with which a proper impact behavior of the tangential impact mechanism is achieved.
  • a method for controlling a machine tool comprising an electric motor, a control device and a Tangentialtschtechnik.
  • the reduction of the engine speed can be achieved by a corresponding reduction of the PWM duty cycle. This can be achieved as effectively as possible, a reduction in the engine speed.
  • the reference value corresponds to the mean value of the motor current that can be measured without the operation of the tangential impact device.
  • Embodiments of control methods for screwing are described below, by way of example for an illustrated tangential impact tool machine. However, the described setting methods can also be carried out with differently configured machine tools.
  • Fig. 1 1 schematically shows an embodiment of a machine tool 1 designed as a tangential impact wrench.
  • the tangential impact driver 1 includes a tool holder 2, an output shaft 3, an electric motor 4, a drive shaft 5, a transmission 6, a sensor 8 for detecting the motor current, a system switch 9, a Tangentialtschtechnik 10, an evaluation device 30, a motor controller 33 and a controller 40th
  • the tool holder 2 is driven by the output shaft 3.
  • the electric motor 4 drives the drive shaft 5.
  • a transmission 6 is interposed for reducing the rotational speed of the drive shaft 5.
  • the drive shaft 5 is permanently rotated in operation about its longitudinal axis 7 in a rotational direction 21.
  • the rotational speed of the electric motor 4 is controlled by the engine controller 33. In a particular embodiment can also be provided that the reduction of the transmission 6 is also adjustable by the motor controller 33.
  • the system switch 9 of the tangential impact driver 1 and the electric motor 4 is activated.
  • the system switch 9 is for this purpose connected to the control device 40, which in turn is correspondingly in communication with the engine control 33.
  • the system switch 9 includes a resistance device, such as e.g. a potentiometer that can be used to output pulse width modulation (PWM) duty cycles to control the electric motor.
  • PWM pulse width modulation
  • the complete operation of the system switch 9 corresponds to a PWM duty cycle of 100%.
  • a half press of the system switch 9 (pressing the system switch 9 by half its distance in the direction A) corresponds to a PWM duty cycle of 50%. This means that a 50% position of the system switch 9 (resistance component) causes a PWM duty cycle of 50%, a 40% position of the system switch 9 causes a PWM duty cycle of 40%, etc ..
  • a Tangential Farbwerk 10 couples the drive shaft 5 with the output shaft 3.
  • the drive shaft 5 can transmit its torque continuously to the output shaft 3 or a Torque of the drive shaft 5 is used for mounting a buffer, which transmits a higher torque to the output shaft 3 in periodic beats.
  • FIG. 2 is shown in longitudinal section an exemplary Tangentialtschwerk 10.
  • the Tangentialtschwerk 10 includes an anvil 11, a rotor 12, a link 13 and a return spring 14.
  • the output shaft 3 is rotatably supported to the drive shaft 5.
  • the anvil 11 is rotatably connected to the output shaft 3, such that a transmitted to the anvil 11 angular momentum acts on the output shaft 3.
  • the anvil 11 has one or more projections 15.
  • Fig. 3 shows a plan view of the anvil 11 from the perspective of the drive shaft 5.
  • the projections 15 may have stop surfaces 16 which are oriented parallel or inclined to the longitudinal axis 7.
  • the rotor 12 is annular and pushed onto the drive shaft 5.
  • the rotor 12 can, guided by the drive shaft 5, move along the longitudinal axis 7.
  • the link 13 is formed on the surface of the drive shaft 5.
  • the gate 13 spirals spirally, the turn increases in the direction of rotation 21 of the drive to the anvil 11 out.
  • the rotor 12 engages in the slot 13. As soon as the rotor 12 moves along the longitudinal axis 7 in the direction 22 to the anvil 11, the rotor 12 is forced into a rotational movement 23 relative to the drive shaft 5. Similarly, the rotor 12 is forced to move along the longitudinal axis 7 as the rotor 12 rotates relative to the drive shaft 5.
  • At the periphery of the rotor 12 at least one hammer 18 is arranged.
  • the hammer 18 has a lateral abutment surface 19, which is formed in a form-fitting or at least partially positive fit to the abutment surfaces 16 of the anvil 11.
  • the rotor 12 and the anvil 11 may mesh with each other like a dog clutch or a slip clutch via the projections 15 and the hammers 18.
  • the rotor 12 can transmit its angular momentum or its torque to the anvil 11 and drive it.
  • the return spring 14 exerts a force on the rotor 12 in the direction 22 to the anvil 11. In a starting position of the tangential impact wrench 1, the rotor 12 therefore in engagement with the anvil 11th
  • the permanent rotation of the drive shaft 5 during operation of the tangential impact wrench 1 is transmitted via the link 13 to the rotor 12. If the rotor 12 can rotate at the same speed, that is, no relative rotation to the drive shaft 5 executes, it remains in the starting position and is not forced to move along the drive shaft 5. In order for the rotor 12 to be able to follow the rotation, however, the rotor 12 must also be able to rotate the anvil 11 against a torque applied by the ground. The torque applied by the substrate must not exceed a threshold value.
  • the threshold value for the torque is essentially a function of the spring force of the restoring spring 14, against which the rotor 12 would have to be deflected, the slope of the slotted guide 13 and possibly the inclination of the stop surfaces 16, 19. These sizes are due to the design of the tangential impact mechanism 10 specified.
  • the threshold value can be, for example, in the range of 1 Nm to 5 Nm or 2 Nm to 3 Nm.
  • the tangential impactor 10 strikes.
  • a beating cycle of the tangential impact wrench 1 will be described beginning with the starting position.
  • the rotor 12 is engaged with the anvil 11.
  • the rotor 12 is prevented by the anvil 11 from rotating synchronously with the drive shaft 5.
  • the link 13 now forces the rotor 12 to move along the longitudinal axis 7 out of engagement with the anvil 11.
  • the rotor 12 may rotate relative to the anvil 11 and to the drive shaft 5.
  • the anvil 11 and the hammer 12 come here again in a relative position in which they can interlock again.
  • the return spring 14 drives the rotor 12 back to the anvil 11.
  • the rotor 12 is accelerated in the direction of the longitudinal axis 7.
  • the gate 13 forces the rotor 12 in a rotational movement 23, whereby the rotor 12 receives an angular momentum.
  • the rotational movement 23 is stopped by the lateral stop of the hammers 18 of the rotor 12 at the projections 15 of the anvil 11.
  • the angular momentum of the rotor 12 is transmitted to the anvil 11.
  • the system is back in the starting position and a new beating cycle begins.
  • the anvil 11 and the output shaft 3 rotate at a smaller angle than the rotor 12 and the drive shaft 5.
  • the rotational speed of the drive shaft 5 may be greater than twice the speed of the output shaft 3 by more than twice.
  • the drive shaft 5 and output shaft 3 are rigidly coupled. Their respective speeds are the same.
  • An impact cycle can be discriminated from non-impact operation based on the different speeds occurring at it.
  • the motor current is detected during operation of the tangential impact wrench 1 at a first engine speed.
  • the detection of the motor current takes place continuously, ie when operating the tangential impact wrench 1 with the use of the tangential impact mechanism and also without the use of the tangential impact mechanism.
  • the value for the motor current detected by the sensor 8 is sent to the evaluation device 30 via a connecting line.
  • the measured motor current is compared with a reference value which is stored in the evaluation device 30.
  • the reference value is determined by the mean value of the motor current is detected at the beginning of the operation of the tangential impact driver 1 when the tangential impact wrench 1 is operated without the use of tangential impact 10 and at the first engine speed.
  • the reference value in other ways.
  • the actually measured motor current is used as the reference value to be compared. If the tangential impact driver 1 is operated with the Tangential Bachwerk 10 and at the first engine speed, the detection of the motor current continues to occur through the sensor 8. Due to an excessive engine speed and associated too high a speed of the drive shaft 5 may cause an improper impact of the Tangential impact device 10 come. This improper impact behavior of the tangential impactor 10 can be determined by detecting the current motor current. As an indication of improper impact, the motor current is increased. The increase in the motor current can be determined by means of the sensor 8 and in comparison with the previously stored reference value.
  • the motor controller 33 then reduces the speed of the motor accordingly to the currently measured motor current not exceeds the reference value. Reducing the speed of the motor is accomplished by the output of a PWM duty cycle, which corresponds to only a percentage of the last current position of the system switch 9 (resistance device).
  • the reduction of the speed of the motor may be accomplished by the output of a PWM duty cycle corresponding to 90% of the last current position of the system switch 9 (resistance device) (ie PWM duty cycle of 90%). If the motor current no longer exceeds the reference value, a proper impact behavior of the tangential impactor 10 is given.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Percussive Tools And Related Accessories (AREA)
EP14160201.1A 2014-03-17 2014-03-17 Reconnaissance de comportement au choc en fonction de la charge Withdrawn EP2921263A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP14160201.1A EP2921263A1 (fr) 2014-03-17 2014-03-17 Reconnaissance de comportement au choc en fonction de la charge

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP14160201.1A EP2921263A1 (fr) 2014-03-17 2014-03-17 Reconnaissance de comportement au choc en fonction de la charge

Publications (1)

Publication Number Publication Date
EP2921263A1 true EP2921263A1 (fr) 2015-09-23

Family

ID=50287950

Family Applications (1)

Application Number Title Priority Date Filing Date
EP14160201.1A Withdrawn EP2921263A1 (fr) 2014-03-17 2014-03-17 Reconnaissance de comportement au choc en fonction de la charge

Country Status (1)

Country Link
EP (1) EP2921263A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018201052A1 (de) * 2018-01-24 2019-07-25 Robert Bosch Gmbh Verfahren zum Steuern einer Drehzahl eines Elektromotors eines Schraubwerkzeuges
EP3991916A4 (fr) * 2019-06-28 2022-08-10 Panasonic Intellectual Property Management Co., Ltd. Outil à percussion

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009038230A1 (fr) * 2007-09-21 2009-03-26 Hitachi Koki Co., Ltd. Outil à percussion
DE102009002479A1 (de) 2009-04-20 2010-10-28 Hilti Aktiengesellschaft Schlagschrauber und Steuerungsverfahren für einen Schlagschrauber

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009038230A1 (fr) * 2007-09-21 2009-03-26 Hitachi Koki Co., Ltd. Outil à percussion
DE102009002479A1 (de) 2009-04-20 2010-10-28 Hilti Aktiengesellschaft Schlagschrauber und Steuerungsverfahren für einen Schlagschrauber

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018201052A1 (de) * 2018-01-24 2019-07-25 Robert Bosch Gmbh Verfahren zum Steuern einer Drehzahl eines Elektromotors eines Schraubwerkzeuges
EP3991916A4 (fr) * 2019-06-28 2022-08-10 Panasonic Intellectual Property Management Co., Ltd. Outil à percussion

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