EP0935514A1 - Method of producing screw connections - Google Patents
Method of producing screw connectionsInfo
- Publication number
- EP0935514A1 EP0935514A1 EP97943860A EP97943860A EP0935514A1 EP 0935514 A1 EP0935514 A1 EP 0935514A1 EP 97943860 A EP97943860 A EP 97943860A EP 97943860 A EP97943860 A EP 97943860A EP 0935514 A1 EP0935514 A1 EP 0935514A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- screw
- acoustic emission
- screwing
- predetermined
- signal
- 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- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 60
- 238000001514 detection method Methods 0.000 claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 238000012544 monitoring process Methods 0.000 claims description 5
- 230000033228 biological regulation Effects 0.000 claims description 2
- 238000011156 evaluation Methods 0.000 claims 1
- 238000009776 industrial production Methods 0.000 abstract description 3
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 15
- 230000036316 preload Effects 0.000 description 7
- 238000002604 ultrasonography Methods 0.000 description 4
- 238000009434 installation Methods 0.000 description 3
- 238000012935 Averaging Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005025 nuclear technology Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
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
- B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
- B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
- B25B23/142—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers
- B25B23/1422—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers torque indicators or adjustable torque limiters
- B25B23/1425—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers torque indicators or adjustable torque limiters by electrical means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P19/00—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes
- B23P19/04—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes for assembling or disassembling parts
- B23P19/06—Screw or nut setting or loosening machines
- B23P19/065—Arrangements for torque limiters or torque indicators in screw or nut setting machines
- B23P19/066—Arrangements for torque limiters or torque indicators in screw or nut setting machines by electrical means
-
- 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
Definitions
- the invention relates to a method for producing screw connections and can preferably be used in assembly processes in industrial production.
- torque or angle measurement systems are used, which are integrated in the screwing system. If a preset torque is reached when the screw is screwed in, a signal output by the torque or angle of rotation measurement system is used to switch off the drive unit, or the screw is turned further by a predetermined angle of rotation.
- a device for determining the pretensioning force of screws located in a component with the aid of at least one coil through which alternating current flows is disclosed, the screws at least partially consisting of the surface facing the coil (s) made of electrically conductive material, and being proportional to the pretensioning force the distance between the screws and at least one coil is detected by the latter as a measurement signal, the head of the screw having a projecting region facing the component.
- This method has the disadvantage that it can only be used for screws made of electrically conductive material. Changes in length caused by plastic deformations cannot be recorded. The lengths to be measured are so small that this process can hardly be used under rough production conditions or only with considerable technical effort.
- DE 401 7726 describes a fastening screw with an at least partially threaded shaft and an actuating end on which a head, a pin boss or the like. are provided, a first end surface being provided at the confirmation end of the fastening screw and a second end surface being provided at the free end of the shaft, and measuring surfaces for ultrasonic measurement are provided in both end surfaces, which extend only over part of the end surfaces and to the end surfaces in the sense of a Elevation and / or depression are arranged axially offset.
- This device uses ultrasound to measure the change in length of the screw.
- the prestressing force is determined directly from the material characteristics and the geometrical dimensions of the screw using methods known to those skilled in the art.
- the subjects of patent applications DE 1 9507391 and DE 4025430 are based on the same principle.
- the object of the invention is to provide a method for the direct determination of the prestressing force on screw connections, which overcomes the problems described above.
- the object is achieved with a method according to claim 1, wherein two components are pressed together with a predetermined prestressing force by means of a screw which is rotated by an adjustable screwing device. Due to the elongation of the screw, an acoustic emission is emitted from the screw material.
- the process is characterized by the following process steps:
- the acoustic emission signals are evaluated using the methods of sound emission analysis known in the prior art.
- the advantage of the method is that a signal that correlates closely with the pretensioning force is obtained, which is independent of the friction in the thread or on the screw head and can optionally be used to control or regulate the screwing-in process. It is possible to combine this acoustic emission signal with the measurement signals of the measured variables torque, angle of rotation, screw length, yield point, screw-in depth previously known from the prior art. These combinations are used for screw connections in which compliance with specified quality features is particularly closely tolerated. If necessary, it is also possible to combine more than two measured variables. Another and essential advantage of the method is that the acoustic emission is also detected in the vicinity of the screw can be. This is the first time that a method is available for the direct determination of the prestressing force of a screw in a screw connection, in which the measurement variable does not have to be tapped directly on the screw itself.
- a suitable environment is selected on the screw in which the acoustic emission is easy to detect.
- a suitable location is preferably the front or side surface of the screw head or the front surface of the screw end. Depending on the specific installation conditions, another location can be selected that enables direct contact between the sensor for recording the acoustic emission and the screw.
- a suitable location is selected at which the acoustic emission can be easily detected.
- the sound transmission conditions must be taken into account.
- An optimal position is determined by means of a few tests.
- the acoustic emission is detected both directly on the screw and at a suitable location in the immediate vicinity of the screw. With special requirements and under special conditions, this procedure offers greater reliability when evaluating acoustic emissions.
- the screw-in depth of the screw is continuously determined using a depth sensor.
- the signal from the depth sensor exceeds a predetermined limit value T and the detection of the acoustic Emission is started.
- the rotation angle measurement is started.
- the screw spindle with which the screw is screwed in is switched off. It is then checked whether the angle of rotation is in a predetermined range. If the angle of rotation is within the specified range, the screw connection is assessed as good, if the angle of rotation is outside the specified range, the screw connection is assessed as defective.
- the torque on the screw is continuously determined using a torque sensor.
- the signal from the torque sensor exceeds a predetermined limit value M and the detection of the acoustic emission is started.
- a rotation angle measurement is started. The ratio of the two variables is calculated from the determined torque and the angle of rotation. If the acoustic emission reaches a further predetermined limit value E2, the screw spindle is switched off and it is checked whether the ratio of torque / angle of rotation and / or the angle of rotation and / or the torque are within predetermined ranges.
- the screw Before the screw is screwed in, its length L1 is measured. Then, while simultaneously measuring the screw-in depth using a depth gauge and measuring the torque, the screw is screwed in until the screw head rests. With the headrest, the measurement signal of the depth gauge reaches a limit value T, after which the detection of the acoustic emission is started. If the acoustic emission reaches a predetermined value E1, the rotation angle measurement is started. If the acoustic emission reaches a further predetermined value E2, the screw spindle is switched off and the length L2 of the screw is measured. The prestressing force is calculated from the length difference L2-L1 using the known geometric dimensions and the strength characteristics of the screw.
- the production of the screw connection is controlled via the torque or the angle of rotation or the yield point, the monitoring being carried out via the acoustic emission.
- the screw is screwed in while measuring the torque up to the headrest.
- the torque reaches a predetermined value M 1, after which the acoustic emission is detected is started. If the torque reaches a predetermined value M2, the screw spindle is switched off. It is then checked whether the acoustic emissions are within a predetermined range or meet predetermined criteria. This means that the elongation of the screw can be checked indirectly without the disruptive influence of thread and head friction.
- the screw is screwed in while measuring the torque up to the headrest.
- the torque reaches a predetermined value M 1, after which the detection of the acoustic emission and the angle of rotation is started.
- a predetermined angle of rotation D 1 the screw spindle is switched off. It is then checked whether the acoustic emissions are within a predetermined range or meet certain criteria. In particular, this method can be used to determine whether the screw has not been drawn into the area of plastic deformation or has been drawn too far.
- Variant 3 The screw is screwed in while measuring the torque up to the headrest. After the head rest, the torque rises sharply and reaches a predetermined value M 1. At this point the torque / angle of rotation ratio is determined and acoustic emission measurement is started. After a predetermined ratio of torque / angle of rotation, the screw spindle is switched off. It is then checked whether the acoustic emission is within a predetermined range or meets predetermined criteria.
- the method according to the invention is used for redundant monitoring of the screwing-in process. It can be combined with the methods known from the prior art. One of these possible combinations will be explained as an example for others.
- a screw is screwed in while simultaneously measuring the torque using an "operating mode fast".
- a threshold torque M 1 which signals and ensures that the screw head is in place
- an "operating mode slow” is switched on and a rotation angle monitoring is activated at the same time.
- the screw is turned slowly until a technologically predetermined shutdown torque M2 is reached.
- the size of the angle of rotation between M 1 and M2 can be used to determine whether the measured angle of rotation corresponds to a predetermined angle of rotation and thus the screw is tightened in accordance with the technological specification.
- the rotation angle control is monitored redundantly, in which it is determined whether a characteristic cal pattern of the acoustic emission matches a comparison pattern stored in the memory unit.
- This redundant control increases the statistical certainty with which the quality of the screw connection is assessed with regard to the contact pressure.
- This method can preferably be used for tightly toleranced screw connections. Another advantage is that the redundant monitoring can be retrofitted to existing screw-in devices
- FIG. 1 shows the schematic structure of a preferred embodiment of the method according to the invention.
- the screw is placed on the component and screwed in, at the same time the screw-in depth is measured with a depth sensor.
- the depth sensor emits a signal that starts the measurement of the acoustic emission (AE).
- An AE sensor that can be detachably coupled to the screw detects the high-frequency AE signals generated in the screw, which in the present example are in the range from 1 30 to 300 kHz.
- the AE signals are processed into a quasi-static signal. For this purpose, bandpass filtering is first carried out in order to increase the ratio of useful and interference signals.
- the bandpass filter is dimensioned in such a way that disturbing sound signals, which arise from the friction processes in the thread or from other sound sources, are separated from the useful signal, which is generated by the elongation of the screw.
- the signal is then squared and averaging is carried out.
- the averaging as well as the width and position of the frequency range depends on the screw or screw type and is determined by tests. If empirical values are already available for a specific screw type, only an optimization may be necessary.
- further bandpass filters can be used. If the filtered quasi-static signal of the acoustic emission exceeds a predetermined limit value E1, the rotation angle measurement is started. If a further limit value E2 is reached, the screw spindle is switched off.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Automatic Control Of Machine Tools (AREA)
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
- Numerical Control (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19643933 | 1996-10-30 | ||
DE1996143933 DE19643933C1 (en) | 1996-10-30 | 1996-10-30 | Screw connection method for industrial assembly process |
PCT/EP1997/004986 WO1998018601A1 (en) | 1996-10-30 | 1997-09-11 | Method of producing screw connections |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0935514A1 true EP0935514A1 (en) | 1999-08-18 |
Family
ID=7809682
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97943860A Withdrawn EP0935514A1 (en) | 1996-10-30 | 1997-09-11 | Method of producing screw connections |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP0935514A1 (en) |
JP (1) | JP2001511073A (en) |
CN (1) | CN1235570A (en) |
AU (1) | AU719448B2 (en) |
BR (1) | BR9712394A (en) |
CA (1) | CA2269949A1 (en) |
DE (1) | DE19643933C1 (en) |
WO (1) | WO1998018601A1 (en) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE518436C2 (en) * | 1998-05-14 | 2002-10-08 | Atlas Copco Tools Ab | Method for determining the axial force of a threaded fastener when tightening over the tension limit |
DE19944717A1 (en) * | 1999-09-17 | 2001-03-22 | Weber Schraubautomaten Gmbh | Method for operating a screwing device |
DE19944702A1 (en) * | 1999-09-17 | 2001-03-22 | Weber Schraubautomaten Gmbh | Screwing device |
DE10042291C1 (en) * | 2000-08-29 | 2002-02-14 | Fraunhofer Ges Forschung | Method to monitor screwing process; involves using pulse-echo technique before and during screwing process and comparing echo times for screw material and screwing tension |
US20080131228A1 (en) * | 2006-11-30 | 2008-06-05 | Caterpillar Inc. | Fastener tightening system utilizing ultrasonic technology |
JP5163270B2 (en) * | 2008-05-13 | 2013-03-13 | マツダ株式会社 | Bolt fastening method and apparatus |
FR3006765B1 (en) * | 2013-06-11 | 2015-07-03 | Airbus Operations Sas | METHOD AND DEVICE FOR DETECTING AN ACOUSTIC TRANSMITTING PHENOMENON |
US20170321502A1 (en) * | 2016-05-06 | 2017-11-09 | Baker Hughes Incorporated | Use of acoustic emission technology in oilfield tubular make ups |
CN107470896B (en) * | 2017-09-05 | 2019-04-12 | 天合汽车零部件(上海)有限公司 | Fastener external screw thread just matches internal screw thread monitoring device and monitoring method |
DE102019211303A1 (en) * | 2019-07-30 | 2021-02-04 | Robert Bosch Gmbh | Method for recognizing the work progress of a hand machine tool |
DE102021124669A1 (en) | 2021-09-23 | 2023-03-23 | Bayerische Motoren Werke Aktiengesellschaft | Procedure for process control in screwing processes |
CN114952239B (en) * | 2022-06-07 | 2023-10-20 | 江苏悦阳光伏科技有限公司 | Automatic installation and effect detection device for junction box cover of photovoltaic module |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
LU84553A1 (en) * | 1982-12-24 | 1984-10-22 | Benoit De Halleux | METHOD OF MEASURING CONSTRAINT IN A MEDIUM AND ELEMENT AND ASSEMBLY FOR IMPLEMENTING THE METHOD |
JPS60150919A (en) * | 1984-01-13 | 1985-08-08 | Hitachi Ltd | Automatic fastener for screw for mold-frame |
JPH02274441A (en) * | 1989-04-18 | 1990-11-08 | Honda Motor Co Ltd | Looseness detecting device for thread member |
JP2913322B2 (en) * | 1989-09-08 | 1999-06-28 | 横浜ゴム株式会社 | Runflat pneumatic radial tires |
DE4017726C2 (en) * | 1990-06-01 | 1993-12-16 | Kellermann Fa Rudolf | Fastening screw |
DE4025430A1 (en) * | 1990-08-10 | 1992-02-13 | Psm Drucklufttechnik Vertrieb | Torque controlled screwing head - has electroacoustic sensor to measure distortion of bolt under torque |
US5277261A (en) * | 1992-01-23 | 1994-01-11 | Makita Corporation | Tightening tool |
DE4410722A1 (en) * | 1994-03-28 | 1995-10-05 | Bosch Gmbh Robert | Non-contact bolt tightening force measurement appts. for quality control |
JPH0858284A (en) * | 1994-08-29 | 1996-03-05 | Kotobuki:Kk | Propelling pencil |
DE19507391C2 (en) * | 1994-09-06 | 2003-08-14 | Bosch Gmbh Robert | Screwing device for ultrasound-controlled tightening of screw connections |
-
1996
- 1996-10-30 DE DE1996143933 patent/DE19643933C1/en not_active Expired - Fee Related
-
1997
- 1997-09-11 CN CN 97199364 patent/CN1235570A/en active Pending
- 1997-09-11 CA CA002269949A patent/CA2269949A1/en not_active Abandoned
- 1997-09-11 WO PCT/EP1997/004986 patent/WO1998018601A1/en not_active Application Discontinuation
- 1997-09-11 AU AU45549/97A patent/AU719448B2/en not_active Ceased
- 1997-09-11 EP EP97943860A patent/EP0935514A1/en not_active Withdrawn
- 1997-09-11 JP JP51995898A patent/JP2001511073A/en active Pending
- 1997-09-11 BR BR9712394-3A patent/BR9712394A/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO9818601A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU719448B2 (en) | 2000-05-11 |
AU4554997A (en) | 1998-05-22 |
CN1235570A (en) | 1999-11-17 |
BR9712394A (en) | 1999-08-31 |
DE19643933C1 (en) | 1998-03-12 |
WO1998018601A1 (en) | 1998-05-07 |
JP2001511073A (en) | 2001-08-07 |
CA2269949A1 (en) | 1998-05-07 |
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