WO2014044335A1 - Connection element having a specific thread pitch - Google Patents

Connection element having a specific thread pitch Download PDF

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Publication number
WO2014044335A1
WO2014044335A1 PCT/EP2013/000608 EP2013000608W WO2014044335A1 WO 2014044335 A1 WO2014044335 A1 WO 2014044335A1 EP 2013000608 W EP2013000608 W EP 2013000608W WO 2014044335 A1 WO2014044335 A1 WO 2014044335A1
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WO
WIPO (PCT)
Prior art keywords
connection element
pitch
thread
designed
inner thread
Prior art date
Application number
PCT/EP2013/000608
Other languages
French (fr)
Inventor
Olaf Berger
Rudolf Schleicher
Original Assignee
Mwm Gmbh
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 Mwm Gmbh filed Critical Mwm Gmbh
Priority to CN201390000770.5U priority Critical patent/CN204805264U/en
Publication of WO2014044335A1 publication Critical patent/WO2014044335A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B33/00—Features common to bolt and nut
    • F16B33/02—Shape of thread; Special thread-forms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
    • F16B31/04—Screwed connections specially modified in view of tensile load; Break-bolts for maintaining a tensile load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F7/00—Casings, e.g. crankcases or frames
    • F02F7/0021—Construction
    • F02F2007/0041—Fixing Bolts

Definitions

  • Connection element having a specific thread pitch
  • the present disclosure relates generally to a connection element having a shank and an outer thread, which is applied to the shank and which is produced in particular by rolling or any other thread forming method as, for example, a cutting thread forming method.
  • the shank of the connection element may be cylindrical or conical.
  • the present disclosure relates to a connecting rod screw or a cylinder head screw for an internal combustion engine.
  • the present disclosure may relate to drill pipes which are connectable via conical thread connections, particular a drill pipe having an outer thread to be screwed in a corresponding internal thread of another drill pipe.
  • the outer thread on said drill pipe may be conical.
  • connection element having a bore and an inner thread, which is introduced in the bore and which is formed in particular by rolling.
  • the bore may be cylindrical.
  • the present disclosure relates to a highly stressed nut, a connecting rod cap or an engine housing of an internal combustion engine, to which one or more cylinder heads are to be screwed.
  • such a connection element may be part of a drill pipe provided with an internal thread. Said internal thread may be conical.
  • connection element pairing which consists of a first connection element and a second connection element to be screwed to the first connection element.
  • the present disclosure refers further to a tap for forming an inner thread.
  • the present disclosure relates to a forming tool for thread rolling, said tool being designed for the production of connection elements of the type disclosed herein.
  • connection element pairing which comprises a first connection element having an outer thread and a second connection element having a threaded bore, into which the first connection element is to be screwed.
  • Highly stressed screw connections are currently used in a wide range of technical fields in order to releasably interconnect one or more components.
  • highly stressed threaded screws or bolts such as connecting rod screws, connecting rod studs or cylinder head screws, etc. are used for this purpose.
  • Such screws may perhaps also be classified under the general term “expansion screws”.
  • connecting rod screw a component referred to for example as a connecting rod bearing cap is screwed to the matching connecting rod in order to form a large connecting rod eye in the connecting rod.
  • Connecting rod screws of this type are subject to high forces during operation of an internal combustion engine.
  • Cylinder heads in an internal combustion engine are also screwed to the engine housing by means of connection elements having an outer thread.
  • connection elements having an outer thread are provided in the engine housings and the connection bolts or screws can then be bolted or screwed into said bores.
  • connection elements such as connecting rod screws, fracture, in particular in the region of the first or second turn of the thread.
  • the technical problem addressed by the present disclosure is that of at least reducing the risk of fracture of connection elements of this type.
  • connection element having a shank and an outer thread, which runs
  • the outer thread may have a pitch that is smaller than the pitch of the inner thread of a component into which the connection element is to be screwed, if the connection element is designed for use under tensile load. If the connection element is designed for use under compressive load, the outer thread may have a pitch that is greater than the pitch of the inner thread of a component into which the connection element is to be screwed.
  • connection element having a cylindrical bore and an inner thread formed in the bore.
  • the inner thread may have a pitch that is greater than the pitch of the outer thread of a connection element that is to be paired and that is to be screwed into the cylindrical bore having an inner thread, if the connection element to be paired having an outer thread is designed for use under tensile load. If the connection element formed with an outer thread is designed for use under compressive load, the inner thread may have a pitch that is smaller than the pitch of the outer thread of the connection element to be paired, which has an outer thread and is to be screwed into the threaded bore.
  • connection element pairing may comprise a connecting rod screw and a connecting rod bearing cap.
  • a connecting rod shank is screwed to a connecting rod bearing cap by means of the (normally) at least two connecting rod screws.
  • the connecting rod screws may have an outer thread that has a pitch that is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the inner thread.
  • the outer thread may have a pitch that, with a pitch of 2 mm nominal value, is 0.002 to 0.004 mm smaller than the inner thread of the bore in the connecting rod bearing cap.
  • the pitch of one thread i.e. the inner or outer thread
  • the pitch of one thread might be up to 25 or even 30 ⁇ greater or smaller as the other one of the inner or outer thread, depending on the forces acting thereon.
  • a further exemplary embodiment of a connection element pairing according to the invention may comprise a cylinder head screw and an engine housing, to which a cylinder head is to be screwed with the aid of the at least one cylinder head screw.
  • the cylinder head screw may have an outer thread that has a pitch that is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the inner thread.
  • the outer thread may have a pitch that, with a pitch of 2 mm nominal value, is 0.002 to 0.004 mm smaller than the inner thread of the bore for the cylinder head screw in the engine housing.
  • the present disclosure relates to a forming tool for thread rolling.
  • the present disclosure relates to a tap for forming an inner thread, the tap being designed such that the inner thread to be formed has a pitch that is greater than the pitch of an outer thread of a connection element that is to be screwed into the inner thread, if the connection element is designed for use under tensile load. If the connection element to be screwed in the inner thread to be formed with the aid of the tap is designed for use under compressive load, the tap may be designed to form an inner thread having a pitch that is smaller than the pitch of the outer thread of the connection element that is to be screwed into the inner thread.
  • the present disclosure relates to a tap for forming an internal thread.
  • the tap may be designed in such a way that the inner thread to be formed has a pitch of which the tolerance range is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the tolerance range of the thread conforming to standards.
  • the tap may be designed for the production of a standard profile, such as M, Tr, UNC, UNF, UNEF or Withworth, but the pitch to be produced is 1 ⁇ to 5 ⁇ , in particular 3 ⁇ to 4 ⁇ smaller than the standard value.
  • connection element pairing which consists of a first connection element having an outer thread and a second connection element having a threaded bore with an inner thread, into which the first connection element is to be screwed.
  • the pitch of the inner thread can be established, for example, by ascertaining the standard and corresponding tolerances for the inner thread produced.
  • the connection element of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the established inner thread is then selected from a multiplicity of connection elements having an outer thread.
  • a connecting rod screw to be screwed into a bore having an inner thread in a connecting rod bearing cap is selected from a plurality of connecting rod screws.
  • the pitch of the inner thread of the bore in the connecting rod into which a connecting rod screw is to be screwed is established.
  • a connecting rod screw of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the respective inner thread is then selected from a multiplicity of connecting rod screws.
  • the connecting rod screw that has a pitch that is 2 ⁇ to 5 ⁇ , in particular 3 ⁇ to 4 ⁇ , smaller than the pitch of the respective inner thread is selected.
  • the latter dimensional specifications are based in particular on a nominal thread pitch of 2.0 mm.
  • the deviation is smaller with a smaller pitch. Accordingly, the deviation is greater with a greater nominal pitch.
  • the selected connecting rod screw can then be screwed into the corresponding bore having an inner thread to connect a connecting rod shank and the connecting rod bearing cap.
  • a cylinder head screw to be screwed into a bore having an inner thread in an engine housing is selected from a plurality of cylinder head screws.
  • the pitch of the inner thread of a bore in the engine housing into which a cylinder head screw is to be screwed is established.
  • a cylinder head screw of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the respective inner thread is then selected from a multiplicity of cylinder head screws.
  • the selected cylinder head screw can then be screwed into the corresponding bore having an inner thread bore to connect a cylinder head and the engine housing.
  • Fig. 1 shows a schematic longitudinal sectional view of a connection element pairing according to the present disclosure
  • Fig. 2 shows an enlarged illustration of the detail "Z" shown in
  • Fig. 3 shows an illustration resembling the detail "Z" shown in Fig. 2, but which shows the situation under tensile load according to the prior art;
  • Fig. 4 shows a schematic illustration of an exemplary thread of a connection element according to the present disclosure
  • Fig. 5 shows a further exemplary thread of a connection element according to the present disclosure
  • Fig. 6 shows a schematic illustration of the tolerance ranges of a thread of a connection element according to the present disclosure for the thread , shown in Figs. 5 and 6 in accordance with the respective standard;
  • Fig. 7 shows a sectional view of an exemplary cylinder head fastening comprising a plurality of connection elements according to the present disclosure
  • Fig. 7a shows a detail of the sectional view of Fig. 7;
  • Fig. 8 shows a connecting rod, in which the connecting rod cap is screwed by means of a plurality of connection elements according to the present disclosure
  • Fig. 9 shows a schematic illustration of a thread rolling head according to the present disclosure.
  • Fig. 10 shows a schematic view of an exemplary embodiment of drill pipes to be connected via a thread connection according to the present disclosure.
  • Fig. 1 shows a schematic longitudinal sectional view of a connection element 5 having an outer thread 10.
  • the connection element 5 is screwed into a nut 15 having an inner thread 20.
  • the connecting element 5 could be a connecting rod screw or a cylinder head screw for example.
  • the part 15 in Fig. 1 is then a shank 80 of a connecting rod 70.
  • the component 15 is an engine housing 60 having an inner bore with an inner thread.
  • Figs. 2 and 3 show a schematic enlarged illustration of a detail of the connection element connection according to Fig. 1 .
  • Fig. 2 the effect possibly achieved by the invention under tensile load is not shown to scale.
  • Fig. 3 shows the same detail before the screw is stressed in a pairing, which corresponds to the prior art.
  • the connection element 5 is subject to a tensile or stretching load in both cases, for example as occurs at a connecting rod screw of a connecting rod during operation of an internal combustion engine.
  • the pitch p A of the outer thread 10 of the screw 5 and the pitch pi of the inner thread 20 are identical in this case (within the tolerances predefined by a standard).
  • the possible distances between mutually opposed flanks of the inner and outer thread 10, 20 are accordingly substantially identical at each turn "A", “B", “C”, etc. when the screw connection is not yet subject to any stress.
  • the screw 5 is then subject to a tensile load, the screw 5 is normally stretched to a varying extent over the screw length and the mutually opposed flanks of the threads 10, 20 will experience the strongest stresses (bearing stress) at the first turn "A", the second strongest stresses at turn “B” and a yet weaker stress at turn “C”.
  • the turns are exposed to forces of varying strength when the screw 5 is stressed, which may lead to a fracture, in particular at the first turn "A".
  • the embodiment of the outer thread 10 relative to the inner thread 20 of the connection element 5 according to the present disclosure ensures that the pitch P A of the outer thread is smaller than the pitch pi of the inner thread (with a screw 5 exposed to tensile load).
  • the pitch P A of the outer thread is greater than the pitch pi of the inner thread in accordance with the present disclosure. If, with the screw connection according to the invention, a tensile load is exerted on the screw 5, more turns than in the prior art will thus be stressed with equal bearing stresses due to the fact that the pitch pi of the inner thread is greater than the pitch p A of the outer thread.
  • flank contact pressure may be more uniform, in particular at the first, two, three or four turns, and an individual turn is not stressed excessively. On the whole, a lower maximum stress could thus act on an individual turn compared to the prior art. The risk of a fracture of a connection element should thus be reduced.
  • Fig. 4 shows an exemplary thread, as may be provided for an outer thread 10 of a connection element 5.
  • the thread is a metric ISO thread, which is specified for example in standard DIN 13.
  • Such a thread may have a tolerance of 6 g for example.
  • the outer diameter d, the flank diameter d 2 , and the core diameter d 3 of the thread could thus have the following dimensions in accordance with the standard: nominal thread diameter: M5
  • the pitch p A of the outer thread would be 0.8 mm minus 0.1 % to 0.30 %, particularly up to 0.25 %, or in particular minus 0.1 % to 0.2 %, of the pitch pi of the respective inner thread (with the standard tolerances), which can be given by a corresponding shift, for example, of the tolerances for the outer diameter, the flank diameter and the core diameter. Further conventional thread tolerances can also be ascertained for example at www.iso-gewinde.at.
  • the tolerance range shown in Fig. 6 would have the following values in this case in accordance with DIN ISO 965: upper dimension(s): 24 ⁇
  • FIG. 5 A further exemplary inner thread 10 for a connection element 15 according to the present disclosure is shown in Fig. 5.
  • An inner thread may then have the tolerance 6H for example.
  • Further conventional thread tolerances can likewise be ascertained for example at www.iso-gewinde.at.
  • the threads shown in Figs. 1, 2, 4 and 5 may, of course, also be used readily in the form of an inner thread in a component 15, such as an engine housing or a connecting rod, for receiving corresponding screws.
  • connection elements which are designed in accordance with the present disclosure and are used in particular in internal combustion engines and of tools for producing connection elements of this type are shown in Figs. 7-9.
  • Fig. 7 shows a schematic illustration of a cylinder head 50, which is screwed to an engine housing 60 by means of cylinder head screws 55.
  • the cylinder head screws 55 and the respective inner thread 20 of a bore 65 in the engine housing may be selected as explained above.
  • the cylinder head screw 55 may have a pitch that is smaller than the pitch of the inner thread 20 in the engine housing 60. It can thus be ensured, when the cylinder head screw 55 is subject to a tensile load during operation of the internal combustion engine, that the turns of the outer thread of the cylinder head screw 55 are stressed more uniformly than in the prior art. In particular, the risk of a fracture of the cylinder head screw 55 during operation of the internal combustion engine should be reduced.
  • FIG 7a A more detailed view of an exemplary thread connection is shown in Fig 7a.
  • a screw bolt 55 according to the present disclosure having an outer thread 10 in screwed in a corresponding threaded bore in housing 60.
  • the outer thread 10 may have a pitch that is smaller than the pitch of the inner thread of the threaded bore in housing 60, if the screw bolt 55 is designed for use under tensile load.
  • the outer thread 10 may have a pitch that is greater than the pitch of the inner thread of the threaded bore in housing 60, if the screw bolt 55 is designed for use under compressive load.
  • Fig. 8 shows a schematic illustration of a connecting rod 70, which, at one end of a shank 80, has a large connecting rod eye 75, and, at the opposite end, has a small connecting rod eye 85.
  • the large connecting rod eye 75 is formed in combination with a connecting rod bearing cap 90, which is to be screwed on.
  • the connecting rod bearing cap 90 is, in this case, connected or screwed to the connecting rod 70 via four connecting rod screws 95.
  • the connecting rod screws 95 are normally subject to a tensile load during operation of the connecting rod 70 in an internal combustion engine (not shown).
  • the connecting rod screws 95 can be formed with an outer thread 10, which has a pitch that is smaller than the pitch of the inner thread in the part of the connecting rod 70 forming part of the large connecting rod eye 75.
  • a connecting rod screw 95, in the screwed state, should thus be stressed more uniformly than in the prior art during use of the connecting rod 70.
  • the flanks of the outer thread 10 of the connecting rod screws 95 should accordingly be stressed approximately equally.
  • FIG. 9 A schematic illustration of a thread rolling head 150 is shown in Fig. 9.
  • the thread rolling head 150 has an insertion opening 155, into which a shank of a connection element 5 to be provided with an outer thread for example, such as a connecting rod screw 95 or a cylinder head screw 50, is to be introduced.
  • the thread rolling head 150 is designed such that the outer thread 10 to be produced on a connection element 5 has a pitch that is up to 0.30 %, in particular up to 0.25 % or 0.2 %, more particularly up to 2 ⁇ to 5 ⁇ , in particular 3 ⁇ to 4 ⁇ , smaller compared to the pitch of the standard thread.
  • the tolerance range for the pitch to be produced using this tool is determined such that the pitch of the outer thread produced is, in any case, smaller than the pitch of the inner thread.
  • the cylinder head screws 50 or connecting rod screws 95 produced may be stressed more uniformly than before under tensile load.
  • the risk that they will fracture, in particular in the first or second turn, should be reduced.
  • Fig. 10 shows a schematic sectional view of an exemplary embodiment of drill pipes 200, 300 to be connected via a thread connection according to the present disclosure.
  • a first drill pipe 200 may be provided with a conical hole 205.
  • An inner thread 210 may be formed in the conical hole 205.
  • a second drill pipe 300 may be provided with a conical projection 305, on which projection 305 an outer thread 310 being formed.
  • the outer thread 310 might have a pitch that is smaller than the pitch of inner thread 210 of drill pipe 200 into which drill pipe 300 is to be screwed, if drill pipes 200, 300 are designed for use under tensile load.
  • the outer thread 310 might have a pitch that is greater than the pitch of inner thread 205 of drill pipe 200 into which drill pipe 300 is to be screwed, if the drill pipes 200, 300 are designed for use under compressive load.
  • Drill pipes 200, 300 may be used on the technical field of oil or gas production.
  • the two drill pipes 200, 300 may be connected by screwing conical projection 305 of drill pipe 300 into conical hole 205.
  • a plurality of drill pipes 200, 300 having a thread connection as explained herein may be connected to each other, particularly more than two drill pipes.
  • screw connections that can be highly stressed are in particular those according to strength class 9.8, 10.9 or 12.9 according to DIN or strength grade 7 or 8 according to SAE J-429.
  • Outer and inner threads of the type disclosed herein may have a standard profile, such as M, Tr, UNC, UNF, UNEF or Withworth, or any other standard profile according to EN, ISO or DIN.
  • a pitch of an outer thread according to the present disclosure is 2 ⁇ to 5 ⁇ , in particular 3 ⁇ to 4 ⁇ , smaller than the pitch of the respective inner thread if the nominal thread pitch p is 2.0 mm for example.
  • the deviation is smaller with a smaller pitch. Accordingly, the deviation is greater with a greater nominal pitch.
  • the outer thread pitch P A according to the present disclosure may thus only be 1 ⁇ to 2.5 ⁇ smaller with a nominal thread pitch of 1.0 mm for example.
  • An inner thread pitch pi according to the present disclosure may be only 1 ⁇ to 2.5 ⁇ greater with a nominal thread pitch of 1.0 mm for example.
  • an advantage may thus be provided, in particular in the case of highly stressed and highly loaded screw connections.
  • screw connections that are tensioned hydraulically, greater advantages may possibly be achieved, because the yield point cannot be surpassed when the screw material is tightened hydraulically. This means that the screw does not deform plastically and therefore cannot adapt optimally to the nut thread. For example, if a connecting rod screw (and nut thread) is tightened past the yield point, the length of the screw (and/or nut thread) will thus be altered (plastic deformation), thus changing the pitch in the thread. This affects screws and nuts.

Abstract

The present disclosure relates to a connection element (5; 55; 95) having a shank (12) and an outer thread (10), which runs circumferentially over the shank (12). The outer thread (10) may have a pitch that is smaller than the pitch of the inner thread (20) of a component (15; 60; 90) into which the connection element (15; 55; 95) is to be screwed, if the connection element (15; 55; 90) is designed for use under tensile load. If the connection element (15) is designed for use under compressive load, the outer thread (10) may have a pitch that is greater than the pitch of the inner thread (20) of a component (15) into which the connection element (5) is to be screwed. In addition to studs for connecting rod, cylinder head, flywheel and crankshaft counterbalance screw connections, a thread rolling head for producing threads of this type is also claimed.

Description

Description
Connection element having a specific thread pitch
Technical Field
The present disclosure relates generally to a connection element having a shank and an outer thread, which is applied to the shank and which is produced in particular by rolling or any other thread forming method as, for example, a cutting thread forming method. The shank of the connection element may be cylindrical or conical. In particular, the present disclosure relates to a connecting rod screw or a cylinder head screw for an internal combustion engine. In addition, the present disclosure may relate to drill pipes which are connectable via conical thread connections, particular a drill pipe having an outer thread to be screwed in a corresponding internal thread of another drill pipe. The outer thread on said drill pipe may be conical.
The present disclosure further relates to a connection element having a bore and an inner thread, which is introduced in the bore and which is formed in particular by rolling. The bore may be cylindrical. In particular, the present disclosure relates to a highly stressed nut, a connecting rod cap or an engine housing of an internal combustion engine, to which one or more cylinder heads are to be screwed. In addition, such a connection element may be part of a drill pipe provided with an internal thread. Said internal thread may be conical.
In addition, the present disclosure relates to a connection element pairing, which consists of a first connection element and a second connection element to be screwed to the first connection element.
The present disclosure refers further to a tap for forming an inner thread. Lastly, the present disclosure relates to a forming tool for thread rolling, said tool being designed for the production of connection elements of the type disclosed herein.
The present disclosure also relates to a method for selecting a connection element pairing, which comprises a first connection element having an outer thread and a second connection element having a threaded bore, into which the first connection element is to be screwed.
Background
Highly stressed screw connections are currently used in a wide range of technical fields in order to releasably interconnect one or more components. In particular, highly stressed threaded screws or bolts, such as connecting rod screws, connecting rod studs or cylinder head screws, etc. are used for this purpose. Such screws may perhaps also be classified under the general term "expansion screws".
In the case of a connecting rod screw, a component referred to for example as a connecting rod bearing cap is screwed to the matching connecting rod in order to form a large connecting rod eye in the connecting rod. Connecting rod screws of this type are subject to high forces during operation of an internal combustion engine.
Cylinder heads in an internal combustion engine are also screwed to the engine housing by means of connection elements having an outer thread. To this end, bores having an inner thread are provided in the engine housings and the connection bolts or screws can then be bolted or screwed into said bores. Even connecting elements of this type on cylinder heads are also subject to high stresses during operation. In particular, high dynamic stresses occur in this field of application, and corresponding high forces have to be taken up by the connection elements.
In the aforementioned fields of application, it has been noted during operation of internal combustion engines that highly stressed connection elements. of this type, such as connecting rod screws, fracture, in particular in the region of the first or second turn of the thread.
The technical problem addressed by the present disclosure is that of at least reducing the risk of fracture of connection elements of this type.
Summary of the Disclosure
In accordance with a first aspect, the present disclosure relates to a connection element having a shank and an outer thread, which runs
circumferentially over the shank. The outer thread may have a pitch that is smaller than the pitch of the inner thread of a component into which the connection element is to be screwed, if the connection element is designed for use under tensile load. If the connection element is designed for use under compressive load, the outer thread may have a pitch that is greater than the pitch of the inner thread of a component into which the connection element is to be screwed.
In accordance with a further aspect, the present disclosure relates to a connection element having a cylindrical bore and an inner thread formed in the bore. The inner thread may have a pitch that is greater than the pitch of the outer thread of a connection element that is to be paired and that is to be screwed into the cylindrical bore having an inner thread, if the connection element to be paired having an outer thread is designed for use under tensile load. If the connection element formed with an outer thread is designed for use under compressive load, the inner thread may have a pitch that is smaller than the pitch of the outer thread of the connection element to be paired, which has an outer thread and is to be screwed into the threaded bore.
An exemplary embodiment of a connection element pairing according to the disclosure may comprise a connecting rod screw and a connecting rod bearing cap. A connecting rod shank is screwed to a connecting rod bearing cap by means of the (normally) at least two connecting rod screws. In this case, the connecting rod screws may have an outer thread that has a pitch that is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the inner thread. For example, the outer thread may have a pitch that, with a pitch of 2 mm nominal value, is 0.002 to 0.004 mm smaller than the inner thread of the bore in the connecting rod bearing cap.
In case of drill pipes to be connected via a thread connection according to the present disclosure, the pitch of one thread, i.e. the inner or outer thread, might be up to 25 or even 30 μπι greater or smaller as the other one of the inner or outer thread, depending on the forces acting thereon.
A further exemplary embodiment of a connection element pairing according to the invention may comprise a cylinder head screw and an engine housing, to which a cylinder head is to be screwed with the aid of the at least one cylinder head screw. In this case, the cylinder head screw may have an outer thread that has a pitch that is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the inner thread. For example, the outer thread may have a pitch that, with a pitch of 2 mm nominal value, is 0.002 to 0.004 mm smaller than the inner thread of the bore for the cylinder head screw in the engine housing.
In accordance with yet a further aspect, the present disclosure relates to a forming tool for thread rolling. The forming tool may be designed such that an outer thread to be rolled of a connection element has a pitch that is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the nominal thread pitch of the desired thread in the unit of mm (for example p = 2.0 mm).
In accordance with yet a further aspect, the present disclosure relates to a tap for forming an inner thread, the tap being designed such that the inner thread to be formed has a pitch that is greater than the pitch of an outer thread of a connection element that is to be screwed into the inner thread, if the connection element is designed for use under tensile load. If the connection element to be screwed in the inner thread to be formed with the aid of the tap is designed for use under compressive load, the tap may be designed to form an inner thread having a pitch that is smaller than the pitch of the outer thread of the connection element that is to be screwed into the inner thread.
In accordance with yet a further aspect, the present disclosure relates to a tap for forming an internal thread. The tap may be designed in such a way that the inner thread to be formed has a pitch of which the tolerance range is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the tolerance range of the thread conforming to standards. According to an exemplary embodiment of the present disclosure, the tap may be designed for the production of a standard profile, such as M, Tr, UNC, UNF, UNEF or Withworth, but the pitch to be produced is 1 μιτι to 5 μπι, in particular 3 μπι to 4 μη smaller than the standard value.
Yet a further aspect of the present disclosure relates to a method for selecting a connection element pairing, which consists of a first connection element having an outer thread and a second connection element having a threaded bore with an inner thread, into which the first connection element is to be screwed. With this method, the pitch of the inner thread can be established, for example, by ascertaining the standard and corresponding tolerances for the inner thread produced. The connection element of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the established inner thread is then selected from a multiplicity of connection elements having an outer thread.
For example, in accordance with the present disclosure, a connecting rod screw to be screwed into a bore having an inner thread in a connecting rod bearing cap is selected from a plurality of connecting rod screws. With the method according to the disclosure, the pitch of the inner thread of the bore in the connecting rod into which a connecting rod screw is to be screwed is established. A connecting rod screw of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the respective inner thread is then selected from a multiplicity of connecting rod screws. In particular, the connecting rod screw that has a pitch that is 2 μηι to 5 μιτι, in particular 3 μηι to 4 μηα, smaller than the pitch of the respective inner thread is selected. The latter dimensional specifications are based in particular on a nominal thread pitch of 2.0 mm. The deviation is smaller with a smaller pitch. Accordingly, the deviation is greater with a greater nominal pitch. The selected connecting rod screw can then be screwed into the corresponding bore having an inner thread to connect a connecting rod shank and the connecting rod bearing cap.
For example, in accordance with the present disclosure, a cylinder head screw to be screwed into a bore having an inner thread in an engine housing is selected from a plurality of cylinder head screws. With the method according to the disclosure, the pitch of the inner thread of a bore in the engine housing into which a cylinder head screw is to be screwed is established. A cylinder head screw of which the pitch is 0.1 % to 0.3 %, in particular up to 0.2 % or 0.25 %, smaller than the pitch of the respective inner thread is then selected from a multiplicity of cylinder head screws. The selected cylinder head screw can then be screwed into the corresponding bore having an inner thread bore to connect a cylinder head and the engine housing.
Brief Description of the Drawings
Further features and aspects of the present disclosure will become clear from the following description in conjunction with the accompanying drawings, in which:
Fig. 1 shows a schematic longitudinal sectional view of a connection element pairing according to the present disclosure;
Fig. 2 shows an enlarged illustration of the detail "Z" shown in
Fig. 1 ;
Fig. 3 shows an illustration resembling the detail "Z" shown in Fig. 2, but which shows the situation under tensile load according to the prior art;
Fig. 4 shows a schematic illustration of an exemplary thread of a connection element according to the present disclosure; Fig. 5 shows a further exemplary thread of a connection element according to the present disclosure;
Fig. 6 shows a schematic illustration of the tolerance ranges of a thread of a connection element according to the present disclosure for the thread , shown in Figs. 5 and 6 in accordance with the respective standard;
Fig. 7 shows a sectional view of an exemplary cylinder head fastening comprising a plurality of connection elements according to the present disclosure;
Fig. 7a shows a detail of the sectional view of Fig. 7;
Fig. 8 shows a connecting rod, in which the connecting rod cap is screwed by means of a plurality of connection elements according to the present disclosure;
Fig. 9 shows a schematic illustration of a thread rolling head according to the present disclosure; and
Fig. 10 shows a schematic view of an exemplary embodiment of drill pipes to be connected via a thread connection according to the present disclosure.
Detailed Description
Fig. 1 shows a schematic longitudinal sectional view of a connection element 5 having an outer thread 10. In this case, the connection element 5 is screwed into a nut 15 having an inner thread 20. In accordance with the present disclosure, the connecting element 5 could be a connecting rod screw or a cylinder head screw for example. In the former case, the part 15 in Fig. 1 is then a shank 80 of a connecting rod 70. In the latter case, the component 15 is an engine housing 60 having an inner bore with an inner thread.
Figs. 2 and 3 show a schematic enlarged illustration of a detail of the connection element connection according to Fig. 1 . In Fig. 2, the effect possibly achieved by the invention under tensile load is not shown to scale. By contrast, Fig. 3 shows the same detail before the screw is stressed in a pairing, which corresponds to the prior art. By comparing Figs. 2 and 3, the improvement possibly to be achieved by the present disclosure compared to a connection element pairing according to the prior art can be better seen. The connection element 5 is subject to a tensile or stretching load in both cases, for example as occurs at a connecting rod screw of a connecting rod during operation of an internal combustion engine.
As shown in Fig. 3, which illustrates the prior art, the pitch pA of the outer thread 10 of the screw 5 and the pitch pi of the inner thread 20 are identical in this case (within the tolerances predefined by a standard). The possible distances between mutually opposed flanks of the inner and outer thread 10, 20 are accordingly substantially identical at each turn "A", "B", "C", etc. when the screw connection is not yet subject to any stress. If, starting from the state shown in Fig. 3, the screw 5 is then subject to a tensile load, the screw 5 is normally stretched to a varying extent over the screw length and the mutually opposed flanks of the threads 10, 20 will experience the strongest stresses (bearing stress) at the first turn "A", the second strongest stresses at turn "B" and a yet weaker stress at turn "C". In other words: the turns are exposed to forces of varying strength when the screw 5 is stressed, which may lead to a fracture, in particular at the first turn "A".
By contrast, the embodiment of the outer thread 10 relative to the inner thread 20 of the connection element 5 according to the present disclosure ensures that the pitch PA of the outer thread is smaller than the pitch pi of the inner thread (with a screw 5 exposed to tensile load). By contrast, in the case of a screw 5 exposed to compressive load, the pitch PA of the outer thread is greater than the pitch pi of the inner thread in accordance with the present disclosure. If, with the screw connection according to the invention, a tensile load is exerted on the screw 5, more turns than in the prior art will thus be stressed with equal bearing stresses due to the fact that the pitch pi of the inner thread is greater than the pitch pA of the outer thread. In other words: instead of the scenario encountered in the prior art, in accordance with the present disclosure the flank contact pressure may be more uniform, in particular at the first, two, three or four turns, and an individual turn is not stressed excessively. On the whole, a lower maximum stress could thus act on an individual turn compared to the prior art. The risk of a fracture of a connection element should thus be reduced.
Fig. 4 shows an exemplary thread, as may be provided for an outer thread 10 of a connection element 5. In this case, the thread is a metric ISO thread, which is specified for example in standard DIN 13. Such a thread may have a tolerance of 6 g for example. The outer diameter d, the flank diameter d2, and the core diameter d3 of the thread could thus have the following dimensions in accordance with the standard: nominal thread diameter: M5
pitch pA: 0.8 mm
outer diameter d max.: 4.976 mm
outer diameter d min.: 4.826 mm
flank diameter d2 max.: 4.456 mm
flank diameter d2 min.: 4.361 mm
core diameter di max.: 3.995 mm
core diameter di min.: 3.869 mm
In accordance with the present disclosure, the pitch pA of the outer thread would be 0.8 mm minus 0.1 % to 0.30 %, particularly up to 0.25 %, or in particular minus 0.1 % to 0.2 %, of the pitch pi of the respective inner thread (with the standard tolerances), which can be given by a corresponding shift, for example, of the tolerances for the outer diameter, the flank diameter and the core diameter. Further conventional thread tolerances can also be ascertained for example at www.iso-gewinde.at. The tolerance range shown in Fig. 6 would have the following values in this case in accordance with DIN ISO 965: upper dimension(s): 24 μηι
outer diameter tolerance (Td): 150 μη
flank diameter tolerance (Td2): 95 μηι
A further exemplary inner thread 10 for a connection element 15 according to the present disclosure is shown in Fig. 5. An inner thread may then have the tolerance 6H for example. Further conventional thread tolerances can likewise be ascertained for example at www.iso-gewinde.at.
The threads shown in Figs. 1, 2, 4 and 5 may, of course, also be used readily in the form of an inner thread in a component 15, such as an engine housing or a connecting rod, for receiving corresponding screws.
Industrial Applicability
Exemplary embodiments of connection elements, which are designed in accordance with the present disclosure and are used in particular in internal combustion engines and of tools for producing connection elements of this type are shown in Figs. 7-9.
Fig. 7 shows a schematic illustration of a cylinder head 50, which is screwed to an engine housing 60 by means of cylinder head screws 55. The cylinder head screws 55 and the respective inner thread 20 of a bore 65 in the engine housing may be selected as explained above. In other words: the cylinder head screw 55 may have a pitch that is smaller than the pitch of the inner thread 20 in the engine housing 60. It can thus be ensured, when the cylinder head screw 55 is subject to a tensile load during operation of the internal combustion engine, that the turns of the outer thread of the cylinder head screw 55 are stressed more uniformly than in the prior art. In particular, the risk of a fracture of the cylinder head screw 55 during operation of the internal combustion engine should be reduced.
A more detailed view of an exemplary thread connection is shown in Fig 7a. Here, a screw bolt 55 according to the present disclosure having an outer thread 10 in screwed in a corresponding threaded bore in housing 60. In this embodiment the outer thread 10 may have a pitch that is smaller than the pitch of the inner thread of the threaded bore in housing 60, if the screw bolt 55 is designed for use under tensile load. Alternatively, the outer thread 10 may have a pitch that is greater than the pitch of the inner thread of the threaded bore in housing 60, if the screw bolt 55 is designed for use under compressive load.
Fig. 8 shows a schematic illustration of a connecting rod 70, which, at one end of a shank 80, has a large connecting rod eye 75, and, at the opposite end, has a small connecting rod eye 85. The large connecting rod eye 75 is formed in combination with a connecting rod bearing cap 90, which is to be screwed on. The connecting rod bearing cap 90 is, in this case, connected or screwed to the connecting rod 70 via four connecting rod screws 95. The connecting rod screws 95 are normally subject to a tensile load during operation of the connecting rod 70 in an internal combustion engine (not shown). In accordance with the present disclosure, the connecting rod screws 95 can be formed with an outer thread 10, which has a pitch that is smaller than the pitch of the inner thread in the part of the connecting rod 70 forming part of the large connecting rod eye 75. Again, a connecting rod screw 95, in the screwed state, should thus be stressed more uniformly than in the prior art during use of the connecting rod 70. The flanks of the outer thread 10 of the connecting rod screws 95 should accordingly be stressed approximately equally.
A schematic illustration of a thread rolling head 150 is shown in Fig. 9. The thread rolling head 150 has an insertion opening 155, into which a shank of a connection element 5 to be provided with an outer thread for example, such as a connecting rod screw 95 or a cylinder head screw 50, is to be introduced. The thread rolling head 150 is designed such that the outer thread 10 to be produced on a connection element 5 has a pitch that is up to 0.30 %, in particular up to 0.25 % or 0.2 %, more particularly up to 2 μπι to 5 μηι, in particular 3 μηι to 4 μηι, smaller compared to the pitch of the standard thread. In other words: the tolerance range for the pitch to be produced using this tool is determined such that the pitch of the outer thread produced is, in any case, smaller than the pitch of the inner thread.
As a result, with inner threads conforming to standards, the cylinder head screws 50 or connecting rod screws 95 produced may be stressed more uniformly than before under tensile load. In addition, the risk that they will fracture, in particular in the first or second turn, should be reduced.
Lastly, Fig. 10 shows a schematic sectional view of an exemplary embodiment of drill pipes 200, 300 to be connected via a thread connection according to the present disclosure. In particular, a first drill pipe 200 may be provided with a conical hole 205. An inner thread 210 may be formed in the conical hole 205. A second drill pipe 300 may be provided with a conical projection 305, on which projection 305 an outer thread 310 being formed.
The basic arrangement as shown in Fig. 10 might be well known. However, according to the present disclosure, in a first embodiment the outer thread 310 might have a pitch that is smaller than the pitch of inner thread 210 of drill pipe 200 into which drill pipe 300 is to be screwed, if drill pipes 200, 300 are designed for use under tensile load. However, if appropriate, in a second embodiment the outer thread 310 might have a pitch that is greater than the pitch of inner thread 205 of drill pipe 200 into which drill pipe 300 is to be screwed, if the drill pipes 200, 300 are designed for use under compressive load. Drill pipes 200, 300 may be used on the technical field of oil or gas production.
In both embodiments, the two drill pipes 200, 300 may be connected by screwing conical projection 305 of drill pipe 300 into conical hole 205. In practice, a plurality of drill pipes 200, 300 having a thread connection as explained herein may be connected to each other, particularly more than two drill pipes.
In the present technical field, screw connections that can be highly stressed are in particular those according to strength class 9.8, 10.9 or 12.9 according to DIN or strength grade 7 or 8 according to SAE J-429. Outer and inner threads of the type disclosed herein may have a standard profile, such as M, Tr, UNC, UNF, UNEF or Withworth, or any other standard profile according to EN, ISO or DIN.
The figures disclosed herein for a pitch according to the present disclosure are merely exemplary. To this end, it is noted that a pitch of an outer thread according to the present disclosure is 2 μπι to 5 μηι, in particular 3 μηι to 4 μπι, smaller than the pitch of the respective inner thread if the nominal thread pitch p is 2.0 mm for example. The deviation is smaller with a smaller pitch. Accordingly, the deviation is greater with a greater nominal pitch. The same is also true, of course, for inner threads according to the present disclosure. The outer thread pitch PA according to the present disclosure may thus only be 1 μηι to 2.5 μηι smaller with a nominal thread pitch of 1.0 mm for example. An inner thread pitch pi according to the present disclosure may be only 1 μιη to 2.5 μηι greater with a nominal thread pitch of 1.0 mm for example.
By altering an outer or inner thread, which conforms to standards, in accordance with the present disclosure, an advantage may thus be provided, in particular in the case of highly stressed and highly loaded screw connections. Even with screw connections that are tensioned hydraulically, greater advantages may possibly be achieved, because the yield point cannot be surpassed when the screw material is tightened hydraulically. This means that the screw does not deform plastically and therefore cannot adapt optimally to the nut thread. For example, if a connecting rod screw (and nut thread) is tightened past the yield point, the length of the screw (and/or nut thread) will thus be altered (plastic deformation), thus changing the pitch in the thread. This affects screws and nuts. However, if the yield point is not surpassed (as is often the only option with hydraulic tightening) the plastic deformation and adaptation of the thread cannot be utilized. Due to a thread design of the present type however, a more uniform bearing pressure at the thread flanks can be achieved, even without plastic deformation.
Although the exemplary embodiments of this disclosure described herein can be used in practice without departing from the scope of protection of the following claims, it is obvious to a person skilled in the art consulting this disclosure that various modifications and variations can be made. Other embodiments are readily obvious to a person skilled in the art under
consideration of the description and with application of the disclosure. The description and the exemplary embodiments are merely intended to be exemplary. The actual scope of protection is delimited solely by the following claims and equivalents thereto.

Claims

Claims
1. A connection element (5; 55 ; 95) having:
a shank (12),
an outer thread (10), which runs circumferentially over the shank (12),
the outer thread (10) having a pitch that is smaller than the pitch of the inner thread (20) of a component (15; 60; 90) into which the connection element (15; 55; 95) is to be screwed, if the connection element (15; 55; 90) is designed for use under tensile load,
and/or
the outer thread (10) having a pitch that is greater than the pitch of the inner thread (20) of a component (15) into which the connection element (5) is to be screwed, if the connection element (15) is designed for use under compressive load.
2. The connection element (5; 55; 95) according to claim 1, wherein:
the outer thread (10) has a pitch that is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, more particularly 0.1 % to 0.25 %, smaller than the pitch of the inner thread (20), if the connection element (5; 55; 95) is designed for use under tensile load, and /or
the outer thread (10) has a pitch that is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, more particularly 0.1 % to 0.25 %, greater than the pitch of the inner thread (20), if the connection element (5) is designed for use under compressive load.
3. The connection element (5; 55; 95) according to any one of the preceding claims, wherein: the outer thread (10) has a pitch that is 2 μπι to 5 μπα and in particular 3 μπι to 4 μπι smaller than the pitch of the inner thread (20), if the connection element (5; 55; 95) is designed for use under tensile load, and/or the outer thread (10) has a pitch that is 2 μπι to 5 μηι and in particular 3 μηι to 4 μηι greater than the pitch of the inner thread (20), if the connection element (5) is designed for use under compressive load.
4. The connection element (5; 55; 95) according to any one of the preceding claims, in which:
the outer thread (10) lies within a tolerance range that is 0.1 % to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the tolerance range conforming to standards according to the thread type on which the respective inner thread (20) is based, if the connection element (5; 55; 95) is designed for use under tensile load, and/or
the outer thread (10) lies within a tolerance range that is 0.1 % to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, greater than the tolerance range conforming to standards according to the thread type on which the respective inner thread (20) is based, if the connection element (5) is designed for use under compressive load.
5. The connection element (5; 55; 95) according to any one of the preceding claims, wherein the outer thread (10) is designed in accordance with a standard profile, such as M, Tr, UNC, UNF, UNEF or With worth,
of which the pitch, however, is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the standard value, if the connection element (5; 55; 95) is designed for use under tensile load,
and/or of which the pitch, however, is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, greater than the standard value, if the connection element (5) is designed for use under compressive load.
6. The connection element (5; 55; 95) according to any one of the preceding claims, wherein the connection element is a highly stressed screw (5; 55; 95) of strength class 9.8, 10.9 or 12.9 according to DIN or strength grade
7 or 8 according to SAE J-429.
7. The connection element according to any one of the preceding claims, wherein the connection element is a stud or stud bolt for a screw connection that is to be tightened hydraulically, for example a connecting rod, cylinder head, flywheel, main bearing block or crankshaft counterbalance screw connection.
8. The connection element according to any one of the preceding claims, wherein the connection element is a connecting rod screw (95) for screwing together a connecting rod shank (80) and a connecting rod bearing cap (90).
9. The connection element according to any one of claims 1 - 7, wherein the connection element is a screw (55) for screwing a cylinder head (50) to an engine housing (60).
10. A connection element (15; 60; 80) having:
a cylindrical bore;
an inner thread (20), which runs circumferentially in the bore; the inner thread (20) having a pitch that is greater than the pitch of the outer thread (10) of a further connection element (5) that is to be screwed into the cylindrical bore having an inner thread (20), if the connection element (15 ; 60; 80) is designed for use under tensile load;
and/or
the inner thread (20) having a pitch that is smaller than the pitch of the outer thread (10) of a further connection element (5) that is to be screwed into the connection element (15), if the connection element (15) is designed for use under compressive load.
1 1. The connection element (15) according to claim 10, wherein the connection element is a nut (15).
12. The connection element according to claim 10, wherein the connection element is a shank (80) of a connecting rod (70) having a bore with an inner thread, into which the connecting rod bearing screw (95) is to be screwed.
13. The connection element according to claim 10, wherein the connection element is an engine housing (60), to which a cylinder head (50) is to be screwed by means of at least one cylinder head screw (55).
14. A connection element pairing, having:
a first connection element (5; 55; 95) according to one of claims 1-9; and
a second connection element (15; 60; 80) according to one of claims 10-13, into which the first connection element (5; 55; 95) is to be screwed.
15. A forming tool (150) for thread rolling, which is designed in such a way that the outer thread (10) to be produced has a pitch of which the tolerance range is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the tolerance range of the thread conforming to standards.
16. The forming tool (150) according to claim 15, wherein the forming tool is designed for the production of a standard profile, such as M, Tr, UNC, U F, UNEF or Withworth, but the pitch to be produced is 1 μν to 5 μηι, in particular 3 μιη to 4 μπι smaller than the standard value.
17. The forming tool according to claim 15 or 16, wherein the forming tool is a thread rolling head (150).
18. A tap for forming an inner thread (20), the tap being designed such that the inner thread (20) to be formed has a pitch (pi) that is greater than the pitch (pA) of an outer thread (10) of a connection element (5) that is to be screwed into the inner thread (20), if the connection element (15; 60; 80) is designed for use under tensile load, and/or the tap being designed such that the inner thread (20) having a pitch (pi) that is smaller than the pitch pitch (pA) of the outer thread (10) of a connection element (15) that is to be screwed into the inner thread (20), if the connection element (15) is designed for use under compressive load.
19. A tap for forming an inner thread (20), which is designed in such a way that the inner thread (20) to be formed has a pitch (p of which the tolerance range is up to 0.30 %, more particularly up to 0.25 %, or in particular up to 0.2 %, smaller than the tolerance range of the thread conforming to standards.
20. The tap according to claim 18 or 19, wherein the tap is designed for the production of a standard profile, such as M, Tr, U C, UNF, UNEF or Withworth, but the pitch to be produced is 1 μιη to 5 μηι, in particular 3 μηι to 4 μηι smaller than the standard value.
21. A method for selecting a connection element pairing, which comprises a first connection element (5; 55; 95) having an outer thread (10) and a second connection element (15; 60; 80) having a threaded bore, into which the first connection element (5; 55; 95) is to be screwed, said method comprising the following method steps:
establishing the pitch of the inner thread (20) of the threaded bore; selecting, from a multiplicity of connection elements (5; 55; 95) having an outer thread (10), the connection element (5; 55; 95) of which the pitch is up to 0.30 %, more particularly up to 0.25 %, or in particular 0.1 % to 0.2 %, smaller than the pitch of the inner thread (10) of which the pitch has been established; and
determining that the selected connection element (5; 55; 95) is to be screwed into the threaded bore of which the pitch has been established.
22. The method according to claim 21 , wherein the connection element is a stud or stud bolt for a screw connection that is to be tightened hydraulically, for example a connecting rod, cylinder head, flywheel or crankshaft counterbalance screw connection.
23. The method according to claim 21 or 22, wherein a connecting rod screw (95) to be screwed into a bore having an inner thread in a connecting rod shank (80) is selected from a plurality of connecting rod screws.
24. The method according to claim 21 or 22, wherein a cylinder head screw (55) to be screwed into a bore having an inner thread in an engine housing (50) is selected from a plurality of cylinder head screws (55).
PCT/EP2013/000608 2012-09-21 2013-03-01 Connection element having a specific thread pitch WO2014044335A1 (en)

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DE202012009154.9 2012-09-21

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WO2023143911A1 (en) * 2022-01-25 2023-08-03 Fontana Fasteners R.D. S.R.L. Method and apparatus for a fastener having a progressive thread profile

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DE102017128099A1 (en) * 2017-11-28 2019-05-29 Gebr. Heller Maschinenfabrik Gmbh Workpiece carrier device
DE102019122279A1 (en) * 2019-06-04 2020-12-10 Schaeffler Technologies AG & Co. KG Connecting element with a connecting part having a thread

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DE3248696A1 (en) * 1982-12-30 1984-07-05 Kraftwerk Union AG, 4330 Mülheim Screw connection between a nut and an axially pretensioned bolt
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CN106438657A (en) * 2016-12-07 2017-02-22 石文祥 Thread pitch interference fit thread, threaded connector and corrected thread machining tool
WO2023143911A1 (en) * 2022-01-25 2023-08-03 Fontana Fasteners R.D. S.R.L. Method and apparatus for a fastener having a progressive thread profile

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DE202012009154U1 (en) 2012-10-31

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