SE1250571A1

SE1250571A1 - dRILL BIT

Info

Publication number: SE1250571A1
Application number: SE1250571A
Authority: SE
Inventors: Goeran Stenberg; Tommy Stahre; Thomas Oesterholm; Alexander Beronius; Jimmy Carlsson
Original assignee: Atlas Copco Secoroc Ab
Priority date: 2012-06-01
Filing date: 2012-06-01
Publication date: 2013-12-02
Also published as: SE537726C2

Abstract

18 Sammandrag: Borrkrona (1) for slaende bergborrning innefattande en anslutningsdel (2) for samverkan med en borrstang och en far ingrepp mot berg utformad och i en avverkningsriktning (A) riktad avverkningsdel (3) med ett flertal frontalt utskjutande stift i form av bergbearbetande insatser, varvid namnda stift ar fordelade i radiell led saval som i vridled i forhallande till en huvudaxel (H) fOr borrkronan, och varvid borrkronan uppvisar en frontalt i avverkningsdelen mynnande spolkanal (4) for framtransport av spolmedium. I ett centralt frontalt omrade (C) av avverkningsdelen mynnar namnda spolkanal (4) med en kant (5") av ett mynningsparti (5) i anslutning till namnda huvudaxel och ar ett snedstallt stift (6) sá anordnat att en langsaxel (L) for det snedstallda stiftet bildar en spetsig vinkel (a) med en langsriktning for borrkronan (1), och att en fOr ingrepp med berg avsedd avverkningsande (7) av det snedstallda stiftet utskjuter sá att ett ytomrade (8) av avverkningsanden befinner sig i anslutning till dels namnda mynningsparti (5), dels namnda huvudaxel (H). Fig. 1 18 Summary: Drill bit (1) for striking rock drilling comprising a connecting part (2) for co-operation with a drill rod and a father intervention against rock designed and in a felling direction (A) directed felling part (3) with a plurality of frontal projections pins in the form of rock processing inserts, said pins being distributed in the radial direction as well as in the pivot joint in relation to a main axis (H) for the drill bit, and the drill bit having a flushing channel opening frontally in the felling part (4) for forward transport of flushing medium. In a central frontal area (C) of the felling part opens said spool channel (4) with an edge (5 ") of a mouth portion (5) adjacent to said main shaft and is an inclined pin (6) so arranged that a longitudinal axis (L) of the inclined pin forms a pointed angle (a) with a longitudinal direction of the drill bit (1), and that a For engagement with rock intended felling end (7) of the inclined pin protrudes so that a surface area (8) of the felling end is located in connection with partly the said mouth portion (5) and partly the said main shaft (H). Fig. 1

Description

1 BORRKRONA UPPFINNINGENS OMRADE Fareliggande uppf inning avser en borrkrona far slaende bergborrning innefattande ett flertal frontalt utskjutande stift i form av bergbearbetande insatser, varvid borrkronan uppvisar en frontalt i avverkningsdelen mynnande spolkanal for framtransport av spolmedium. 1 BORRKRONA FIELD OF THE INVENTION Dangerous invention refers to a drill bit father striking rock drilling comprising a plurality of frontal projections pin in the form of rock processing inserts, the drill bit having a flushing channel opening in front of the felling part for forward transport of flushing medium.

UPPFINNINGENS BAKGRUND Stiftborrkronor far bergborrning inkluderar ett antal hardmetallstift insatta i en stomme, i vilken en eller flera spolkanaler vanligen ar arrangerade for att transportera spolmedium fran den ihaliga borrstangens insida till borrstrangens front. BACKGROUND OF THE INVENTION Pin drill bits for rock drilling include a number of cemented carbide pins inserted into a body in which one or more flushing channels are usually arranged to transport flushing medium from the inside of the hollow drill rod to the front of the drill string.

Spolmediet strommar sedan via spolkanaler i borrkronans framre del for kontinuerlig borttransport av krossat berg. Det krossade berget vidaretransporteras sedan typiskt utmed vaggen av det bildade borrhalet utanfor borrstrangen upp till mynningen av halet. The flushing medium then flows via flushing channels in the front part of the drill bit for continuous removal of crushed rock. The crushed rock is then typically transported along the cradle of the formed drill tail outside the drill string up to the mouth of the tail.

I andamal att reducera tryckfallet far spolmedium genom spolkanaler i borrkronor och i andamal att soka erhalla effektiv spolning av borrkronornas front dr vanligtvis tva eller flera spolhal arrangerade mynnande i borrkronornas front. Aven sidospolhal forekommer vid traditionella borrkronor. In order to reduce the pressure drop, flushing medium passes through flushing channels in the drill bits and in the case of seeking to obtain efficient flushing of the front of the drill bits, usually two or more flushing holes arranged opening in the drill bits. front. Even the side coil hall occurs in traditional drill bits.

Som exempel pa teknikens bakgrund kan namnas: - US 3,941,197, vid vilken en snedstalld spolkanal mynnar i ett frontalt omrade av borrkronan. Examples of the background of the technology are: US 3,941,197, in which an inclined flushing channel opens into a frontal area of the drill bit.

- US 4,069,880, vilken beskriver en borrkrona med en spolkanal mynnande i fronten och med axiellt riktade stift fordelade Over borrkronans frontyta. 77195 20120418 2 UPPFINNINGENS ANDAMAL OCH VIKTIGASTE KkNNETECKEN Det dr ett andamAl med uppfinningen att tillhandahAlla en borrkrona av inledningsvis namnt slag, vilken utgar en vidareutveckling av kanda borrkronor av det slag som uppvisar en frontalt i avverkningsdelen mynnande spolkanal for framtransport av spolmedium till borrkronans front. Det krossade berget fors sedan bort utmed vaggen av det bildade borrhdlet utanfor borrstrdngen upp till mynningen av haslet. US 4,069,880, which describes a drill bit with a flushing channel opening into the front and with axially directed pins distributed Over the front surface of the drill bit. 77195 20120418 2 ANDAMAL AND MOST IMPORTANT CHARACTERISTICS OF THE INVENTION It is an object of the invention to provide a drill bit of an initially named type, which constitutes a further development of known drill bits of the type which exhibit a flushing channel opening in front of the felling part forward transport of flushing medium to the front of the drill bit. The crushed rock is then carried away along the cradle of the formed drill hole outside the drill string up to the mouth of the hazel.

Detta andamal uppnas vid en borrkrona av inledningsvis ndmnt slag genom att i ett centralt frontalt omrade av avverkningsdelen: ndmnda spolkanal mynnar med en kant av ett mynningsparti i anslutning till borrkronans huvudaxel, och ett snedstallt stift dr anordnat sá att en langsaxel for det snedst&llda stiftet bildar en spetsig vinkel med en ldngsriktning for borrkronan, och att en far ingrepp med berg avsedd avverkningsdnde av det snedstdllda stiftet utskjuter sâ att ett ytomrAde av avverkningsdnden bef inner sig i anslutning till dels namnda mynningsparti, dels namnda huvudaxel. This andamal is achieved at a drill bit of initially ndmnt kind by being in a central frontal area of the felling part: said flushing channel opens with an edge of a mouth portion adjacent to the main shaft of the drill bit, and an oblique pin there arranged so that a longitudinal axis for it the oblique pin forms an acute angle with a longitudinal direction of the drill bit, and that a single engagement with rock intended felling end of the inclined pin protrudes so that a surface area of the felling end is located in connection with partly the said mouth portion and partly the said main axis.

Hdrigenom uppnds ett flertal fordelar i jamforelse med borrkronor vars spolkanaler mynnar pA avstand fran huvudaxeln far borrkronan. Vid sAdana tidigare kdnda borrkronor, och i synnerhet vid borrkronor, i vilka ett flertal spolhal mynnar frontalt i borrkronan, uppkommer en s. k. dad zon, till vilken spolningen snarare inmatar an borttransporterar avverkat material. I motsats till vid dessa traditionella borrkronor erhAlls genom uppfinningen effektivare spolning och ddrmed battre forutsdttningar far effektiv avverkning. In this way, a number of advantages are obtained in comparison with drill bits whose flushing channels open at a distance from the main axis get the drill bit. At such previously known drill bits, and in particular at drill bits, in which a plurality of flushing holes open in front of the drill bit, a so-called dad zone arises, to which the flushing rather feeds on transports away harvested material. In contrast to these traditional drill bits, the invention provides more efficient flushing and thus better conditions for efficient felling.

Genom att det undviks att avverkat material bortspolas mer effektivt och i synnerhet inte ansamlas i denna dada zon beh8ver inte slagenergi tas i ansprak far att utfora slag mot och mala sAdant redan avverkat material, utan det tillforsakras pa ett effektivt satt sterre mejligheter far 77195 20120418 3 borrkronan att verka mot berg ± form av icke krossat material. Detta medf8r ocksa reducerat slitage far en uppfinningsenlig borrkrona. By avoiding that harvested material is washed away more efficiently and in particular do not accumulate in this dada zone does not require impact energy to be used to perform blows against and grind such already harvested material, but it assured in an effectively put greater opportunities father 77195 20120418 3 the drill bit to act against rock ± form of non-crushed material. This also entails reduced wear for a drill bit according to the invention.

Effektivare spolning mojliggOr aven att relativt sett mindre energi atgar for spolningen. Detta medfor ett battre lage med befintlig spolpump fbr en bergborrningsanlaggning liksom i samband med dimensionering av nya anlaggningar. Uppfinningen majliggor aven en anpassning av borrkronans spolkanal sá att flodesmotstandet stor utstrackning kan reduceras. More efficient flushing is also possible in relative terms less energy is required for the flushing. This leads to a better with an existing flushing pump for a rock drilling plant as well as in connection with dimensioning of new plants. The invention also makes it possible to adapt the flushing channel of the drill bit so that the river resistance can to a large extent reduced.

Genom uppfinningen uppnas att spolkanalen kan tillatas att mynna nara centrumaxeln i borrkronans front utan att det riskeras att en kvarstaende central bergplugg skapas vid borrningen, vilken annars skulle kunna tappa till en spolkanalmynning. The invention achieves that the flushing channel can be allowed to open near the center axis in the front of the drill bit without the risk of a remaining central rock plug being created during drilling, which could otherwise drop to a flushing channel opening.

Detta uppnas genom det snedstallda stiftet, som kan placeras i nara anslutning till mynningen, genom att det snedstallda stiftets rotparti ãr riktat i en riktning fran spolkanalen. Detta arrangemang tillforsakrar stabil och effektiv fasthallning av detta snedstallda stift utan att omgivande material i borrkronan behover inkrakta pa spolkanalens forlopp. This is achieved by the inclined pin, which can be placed in close proximity to the mouth, in that the root portion of the inclined pin is directed in a direction away from the flushing channel. This arrangement ensures stable and effective holding of this inclined pin without surrounding material in the drill bit needs to be influenced on the course of the flushing channel.

Genom det snedstallda stiftets placering sa att ett ytomrade av avverkningsanden bef inner sig i anslutning till dels namnda mynningsparti, dels namnda huvudaxel i kombination med den i det narmaste centralt placerade mynningen av spolkanalen, tillforsakras att detta stift i likhet med Ovriga stift ingaende i borrkronan verkar direkt mot okrossat berg i den for borrning avsedda bergformationen, vilket ger effektivare och darmed mer ekonomisk borrning. Due to the location of the inclined pin, it is said that a surface area of the felling spirit is adjacent to partly the said mouth portion, partly the said main shaft in combination with the nearest centrally located mouth of the flushing channel, it is ensured that this pin, like other pins inputting in the drill bit, acts directly against crushed rock in the rock formation intended for drilling, which gives more efficient and thus more economical drilling.

Med angivelsen om placering av det snedstallda stiftet med namnda ytomrade ± anslutning till huvudaxeln avses att nagot ytparti darav inte b5r vara pa ett star-re avstand fran 77195 20120418 4 huvudaxeln an att effektiv bergavverkning sker genom att det snedstallda stiftet i praktiken verkar direkt mot annu inte avverkat berg. Harigenom undviks att energi AtgAr for slag mot redan sOnderdelade bergstycken. The indication of the location of the inclined pin with said surface area ± connection to the main shaft means that any surface portion thereof should not be at a greater distance from 77195 20120418 4 the main axis indicates that efficient rock felling takes place by the oblique pin in practice acting directly on rock not yet felled. This avoids energy AtgAr for blows to already decomposed rock pieces.

Spolning i direkt anslutning till borrkronans centrum medfOr som ovan diskuterats allmant fordelar vad avser slitageminskning, effektivare borrning och minskad energiAtgAng for sAval borrning som spolning. Flushing in direct connection to the center of the drill bit entails, as discussed above, general advantages in terms of wear reduction, more efficient drilling and reduced energy consumption for sAval drilling as flushing.

Det ar en fordel att spolkanalen har en tvarsnittsarea, som inte minskar efter sin utstrackning, utan foretrAdesvis ar tvArsnittsarean av spolkanalen efter dess langd fram till utloppsmynningen i borrkronans frontyta vasentligen samma tvarsnittsarea Over sin langd. Mer faredraget ar tvarsnittsarean av spolkanalen Atminstone lika star som arean av borrkronans tapphAl eftersom detta ger ett fordelaktigt lAgt stromningsmotstAnd far spolfluiden. Mest foredraget är att tvarsnittsarean av spolkanalen akar kontinuerligt eller i steg langs spolkanalens utstrackning eftersom detta ger bast stromningsforutsattningar for fladet. It is an advantage that the flushing channel has one cross-sectional area, which does not decrease according to its extent, but Preferably, the cross-sectional area of the flushing channel according to its length up to the outlet orifice in the front surface of the drill bit is essentially the same cross-sectional area over its length. More dangerous is the cross-sectional area of the flushing channel at least equal stands as the area of the drill bit tapphAl because this gives a advantageously LOW flow resistance gets the flushing fluid. Most preferred is that the cross-sectional area of the flushing channel plows continuously or in steps along the extent of the flushing channel as this provides the best flow conditions for the surface.

TapphAlet har A sin sida fOredraget Atminstone samma tvarsnittsarea som en spolkanal i en borrstrang, som borrkronan ãr ihopkopplad med. TapphAlet has A on its side Lecture At least the same cross-sectional area as a flushing channel in a drill string, with which the drill bit is connected.

Det har vidare visat sig att det generellt ãr av star betydelse vid borrkronor av det slag, till vilket uppfinningen hanfors, att spolkanalen utformas med en tillrackligt star tvarsnittsarea (spolkanalarea - S) i forhAllande till en area av ett borrhAl (borrhAlsarea - B), som skapas vid driften av borrkronan. Overraskande har det visat sig att relativt smA andringar av detta forhAllande i riktning av en minskning av forhAllandet S/B medfor betydande tryckfallsokningar, vilket medfar samre spoleffekt och darmed risk for mindre effektiv borrning. 77195 20120418 For okad forstaelse av denna aspekt kan llamas att vid en borrkrona med en diameter av 76 mm och vid en viss stromning som jamforelse endast: S/B=0,060 ger ett tryckfall av 1,8 bar S/B=0,047 ger ett tryckfall av 2,4 bar S/D=0,028 ger ett tryckfall av 5,2 bar Ett allmant foredraget varde S/B är lampligen Over 0,05. It has further been found that it is generally of great importance in drill bits of the type to which the invention hanfors, that the flushing channel is designed with a sufficient star cross-sectional area (flush channel area - S) in relation to an area of a borehole (borehole area - B), which is created during the operation of the drill bit. Surprisingly, it has been found that relatively small changes in this ratio in the direction of a reduction of The S / B ratio entails significant pressure drop increases, which entails a coil coil effect and thus a risk of less efficient drilling. 77195 20120418 For a better understanding of this aspect, it can be called that at a drill bit with a diameter of 76 mm and at a certain flow as a comparison only: S / B = 0.060 gives a pressure drop of 1.8 bar S / B = 0.047 gives a pressure drop of 2.4 bar S / D = 0.028 gives a pressure drop of 5.2 bar A generally preferred value S / B is probably Over 0.05.

Den totala kanalens tvarsnittsarea Over tapphAlet - spolkanalen - fri area mellan borrkronans front och borrhalets botten - fri area forbi fronten mot periferin av borrkronan - fri area mellan borrkronan och borrhAlsvaggen ska inte uppvisa nagon minskning eller strypning efter sitt forlopp eftersom detta medfar Okat tryckfall och reducerad spolverkan. Total cross-sectional area of the total channel Over tapphAlet - flushing channel - free area between the front of the drill bit and the bottom of the drill tail - free area past the front towards the periphery of the drill bit - free area between the drill bit and the drill hole The cradle should not show any reduction or throttling after its course as this causes increased pressure drop and reduced rinsing effect.

Starst betydelse i detta sammanhang ar dock att arean bibehalls i sialva borrkronan, dvs. langs forloppet av tapphal - spolkanal, varvid saledes speciellt arean av spolkanalen mAste vara tillrhckligt stor, enligt ovan. The most important thing in this context, however, is that the area is maintained in the sialva drill bit, ie. along the course of the spighal - flushing channel, whereby especially the area of the flushing channel must be sufficiently large, as above.

Jamforande forsok har gett vid handen att en spolkanal utformad med samma tvarsnittsarea efter sin utstrdckning och Overensstammande med tapphAlet fOrorsakar ett tryckfall, som är endast c:a en tredjedel av vanligt forekommande tryckfall fOrorsakat av en spolkanal i en kind borrkrona med spolkanal (-er) med mindre total tvdrsnittsarea. Uppfinningen i sig mOjliggOr hven ph ett effektivt shtt att spolkanalen utformas med jamforelsevis mycket star tvarsnittsarea utan att ge avkall ph avverkningsfunktionen. Comparative attempts have given at hand that a flushing channel formed with the same cross-sectional area according to its extent and In accordance with the tapping holeCauses a pressure drop, which is only about one third of a common pressure drop Caused by a flushing channel in a cheek drill bit with flushing channel (s) with smaller total cross-sectional area. The invention itself It is also possible for an efficient way for the flushing channel to be designed with a comparatively very rigid cross-sectional area without sacrificing the felling function.

I beaktande av det ovansthende, betraffande det snedstallda stiftets placering i forhallande till huvudaxeln, ár 14mpligen namnda mynningsparti belhget i huvudsak motsatt det snedstallda stiftet i farhallande till huvudaxeln eftersom darvid en placering tillAtande stor tvhrsnittsarea av 77195 20120418 6 spolkanalen med ringa stromningshindrande vinkelavvikelser langs dess utstrdckning medges. In view of the above, concerning it the position of the inclined pin in relation to the main axis, The mouth portion 14mplically mentioned is located substantially opposite the oblique pin in relation to the main axis, since in this case a location toAtande large cross-sectional area of 77195 20120418 6 the flushing channel with small flow-preventing angular deviations along its extension is allowed.

Det foredras att det snedstallda stiftet dr ett stift av det slag, som anges i WO 2011/043717, vilket ytterligare bidrar till god livslangd och obefintligt eller Atminstone reducerat omslipningsbehov. It is preferred that the oblique pin pull a pin off the type specified in WO 2011/043717, which further contributes to good longevity and non-existent or At least reduced regrinding need.

Det foredras att langsaxeln for det snedstallda stiftet bildar en spetsig vinkel med namnda huvudaxel eftersom darigenom materialutnyttjandet far det snedstallda stiftets rotparti optimeras och spolkanalens tvdrsnittsarea inte begransas. It is preferred that the longitudinal axis of the inclined pin forms an acute angle with said main axis since thereby the material utilization of the inclined pin root portion is optimized and the cross-sectional area of the flushing channel is not limited.

Lampligen ars namnda spetsiga vinkel mellan ° och 70°. Mer foredraget är namnda spetsiga vinkel mellan ° och 5°. Mest foredraget ãr namnda spetsiga vinkel mellan ° och °. Vid speciella foredragna utforingsformer har ndmnda spetsiga vinkel uppgAtt till ° respektive °. Lampligen ars said pointed angle between ° and 70 °. More preferred is the said acute angle between ° and 5 °. Most preferred is the said acute angle between ° and °. In particularly preferred embodiments, the following acute angles set to ° and °, respectively.

Lampligen utgAr det snedstallda stiftet fran ett avfasat frontytparti av avverkningsdelen eftersom detta ger forenklad tillverkning av borrkronan. Avfasningen är ldmpligen gjord med en vinkel motsvarande ndmnda spetsiga vinkel Det foredras att, sett i avverkningsriktningen, det snedstallda stiftet ars belaget Aterdraget i forhAllande till andra stift hos borrkronan eftersom detta ger en lagre grad av belastning pa det snedstailda stiftet i drift av borrkronan. The oblique pin is preferably made from a bevelled front surface portion of the felling part as this simplifies the manufacture of the drill bit. The chamfering is ldmpligen made at an angle corresponding to the aforesaid acute angle It is preferred that, seen in the felling direction, the inclined pin is coated Aterdraget in relation to other pins of the drill bit as this gives a lower degree of load on the inclined pin in operation of the drill bit.

Vid en foredragen aspekt av uppfinningen utskjuter det snedstallda stiftet sá att det med namnda ytomrade bef inner sig i nara anslutning till namnda huvudaxel, pa ett avstand frAn huvudaxeln som är dimensionerat motsvarande till en vidd av en forvantad krosszon uppkommen vid anvdndning av borrkronan i en fOr denna avsedd bergtyp. Hdrigenom kan mynningspartiet av spolkanalen goras med fordelaktigt Okad storlek genom att det kan forflyttas ett motsvarande stycke i riktning mot det snedstallda stiftet sá att mynningspartiet 77195 20120418 7 till och med omfattar huvudaxeln. Det ska betonas att det dr mom ramen far uppfinningen att det snedstallda stiftet ar placerat sá att det med ndmnda ytomrade bef inner sig i direkt anslutning till, eller tangerande ndmnda huvudaxel. Det az- &yen mom ramen far uppfinningen att det snedstdllda stiftet är placerat sa att det med ndmnda ytomrade omsluter ndmnda huvudaxel, d.v.s. sa att huvudaxeln forloper genom det snedstallda stiftet. In a preferred aspect of the invention, protruding the inclined pin so that it is with said surface area located in close proximity to said main shaft, at a distance from the main shaft which is dimensioned corresponding to a width of a predetermined crushing zone formed when using the drill bit in a rock type intended for this. Hdrigenom can the mouth portion of the flushing channel is advantageously increased in size by allowing a corresponding piece to be moved in the direction of the inclined pin so that the mouth portion 77195 20120418 7 even includes the main shaft. It should be emphasized that within the scope of the invention, the inclined pin is positioned so that it with said surface area is in direct connection with, or tangential to, said main axis. The az- In accordance with the scope of the invention, the inclined pin is positioned so that with said surface area it encloses said main shaft, i.e. said that the main axis runs through the oblique pin.

Lampligen uppvisar avverkningsdelen frontalt atminstone ett vdsentligen radiellt ferlapande spolspar utgaende fran namnda mynningsparti och i princip fran huvudaxeln. Denna utformning av spolspar ger fardelaktig och obehindrad borttransport av avverkat material fran fronten av borrkronan. Det ska betonas att andra konfigurationer av frontala och sidoordnade spolspar dr mojliga och t.o.m. borrkronor av typen "flat face", d.v.s. helt utan frontala spolspar. Lamply, the felling part has a front at least one substantially radially overlapping coil pair emanating from the said estuary and in principle from the main shaft. This design of coil pairs provides smooth and unobstructed removal of felled material from the front of the drill bit. It should be emphasized that other configurations of frontal and lateral coil pairs dr possible and t.o.m. drill bits of the "flat face" type, i.e. completely without frontal coil pairs.

Foredraget ar namnda mynningsparti ett i tvarsektion langstackt, ovalt, avrundat halvmanformat eller fylligt U- format hal. I anslutning till en kant av mynningspartiet befinner sig ndmnda ytomrade av det snedstallda stiftet eftersom denna utformning medger en bra fardelning av spolfluid over borrkronans front. Denna utformning ger dessutom en reducering av stromningsmotstandet i detta omrade av spolkanalen. Nar namnda mynningsparti utgors av ett langstackt hal, bef inner sig namnda ytomrade av det snedstallda stiftet foredraget i anslutning till halets ena langsida. Preferably, the said mouth portion is a transversely elongated, oval, rounded half-man-shaped or full U-shaped format hall. Adjacent to an edge of the mouth portion The above-mentioned surface area of the inclined pin is located because this design allows a good distribution of flushing fluid over the front of the drill bit. This design also provides a reduction in flow resistance in this area of the flushing channel. When the said mouth portion consists of one long-stacked haul, the said surface area of the inclined pin is preferred in connection with one long side of the haul.

Borrkronan uppvisar utover namnda snedstallda stift foretrddesvis dven en forsta uppsattning perifera stift, vilka ar riktade i divergerande riktningar, sett i avverkningsriktningen, och en andra uppsdttning, sett i en radiell ledd for borrkronan mellanliggande stift, vilka ar 77195 20120418 8 anordnade med sina langsaxlar vasentligen parallella med huvudaxeln. The drill bit has, in addition to the aforementioned inclined pins preferably also a first set of peripheral pins, which are directed in diverging directions, seen in the felling direction, and a second set-up, seen in a radial joint for the drill bit intermediate pins, which are 77195 20120418 8 arranged with their longitudinal axes substantially parallel to the major axis.

Det foredras att ett plan genom huvudaxeln bildar ett symmetriplan for det snedstallda stiftet och mynningspartiet, eftersom harigenom mynningsplacering och -storlek kan utformas i riktning av optimering i beaktande av det snedstallda stiftets placering eftersom stiftet da kan placeras narmare huvudaxeln. Sasom forstas av de ovanstaende är det dock fullt majligt att arrangera det snedstallda stiftet sidoplacerat ett sadant symmetriplan om det skulle vara lampligt av nagot annat skal sasom av utrymmesskal. It is preferred that a plane through the major axis forms a plane of symmetry for the inclined pin and the mouth portion, because this allows the mouth location and size to be designed in the direction of optimization taking into account the position of the inclined pin since the pin can then be placed closer to the main axis. As can be understood from the above, however, it is perfectly possible to arrange the inclined pin side-by-side a such a plane of symmetry if it would be appropriate by something else shall sasom of space shells.

Ytterligare sardrag och fordelar framgar av nedanstaende detaljbeskrivning. Additional features and benefits are set forth in the following detailed description.

KORTFATTAD BESKRIVNING AV RITNINGAR Uppfinningen ska nu narmare beskrivas med ledning av utforingsexempel och med hanvisning till bifogade ritningar, pa vilka: Fig. 1 visar en borrkrona enligt uppfinningen i ett axiellt snitt, Fig. 2 visar borrkronan i fig. 1 i en frontvy, Fig. 3a, 3b, 3c och 3d visar frontvyer av alternativt utformade borrkrona enligt uppfinningen, och Fig. 4 visar borrkronan i fig. 1 i drift i ett axiellt snitt. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to exemplary embodiments and with reference to the accompanying drawings, in which: Fig. 1 shows a drill bit according to the invention in one axial section, Fig. 2 shows the drill bit in Fig. 1 in a front view, Figs. 3a, 3b, 3c and 3d show front views of alternatively designed drill bit according to the invention, and Fig. 4 shows the drill bit in Fig. 1 in operation in an axial cut.

BESKRIVNING AV UTFoRINGSEXEMPEL I fig. 1 visas en axiell sektion genom en uppfinningsenlig borrkrona 1, vilken uppvisar en anslutningsdel 2 for samverkan med en ej visad borrstrang och en avverkningsdel 3, vilken i anvandning ar riktad i en avverkningsriktningsriktning A och genom slag och 77195 20120418 9 mellanliggande vridning pa i och for sig }cant satt dr inrattad att krossa och avverka berg far bildande av ett borrhal. I anslutningsdelen 2 ár pa vanligt satt inrattad en honganga for mottagning av en hanganga belagen pa en borrstrangskomponent. DESCRIPTION OF EMBODIMENTS Fig. 1 shows an axial section through a drill bit 1 according to the invention, which has a connection part 2 for cooperation with a drill string (not shown) and a felling part 3, which in use is directed in a felling direction direction A and by impact and 77195 20120418 9 intermediate rotation in and of itself} cant sat there set up to crush and fell rocks form a borehole. In the connection part 2 years in the usual way, a honganga is set up for receiving a hanger aisle mounted on a drill string component.

I avverkningsdelen 3 uppvisar borrkronan 1 en spolkanal 4, vilken forloper fran det inre av anslutningsdelen, dar spolkanalen 4 via ett tapphal 4 ansluter till en central kanal i en ej visad borrstrangskomponent, genom vilken spolfluid nedmatas pa i och for sig }cant satt. Spolkanalen 4 mynnar i ett,utlopp i form av ett mynningsparti 5 frontalt avverkningsdelen 3, och till yttermera visso är mynningspartiet 5 sá belaget att en kant darav, 5', r belagen i nara eller direkt anslutning till en huvudaxel H fOr borrkronan. In the felling part 3 the drill bit 1 has a flushing channel 4, which extends from the interior of the connecting part, where the flushing channel 4 connects via a pinhole 4 to a central channel in a drill string component (not shown), through which flush fluid is fed on in and of itself} cant sat. The flushing channel 4 opens into a, outlet in the form of a mouth portion 5 in front of the felling part 3, and furthermore the mouth portion 5 is so coated that an edge thereof, 5 ', is coated in close or direct connection to a main axis H for drill bit.

Ett snedstallt stift 6 ãr anordnat med en langsaxel L bildande en spetsig vinkel a med huvudaxeln H. Det snedstallda stiftet liar en inriktning sá att en far ingrepp med berg avsedd avverkningsande 7 utskjuter sá att ett ytomrade 8 darav ar belagen i direkt anslutning till dels namnda kant 5' av namnda mynningsparti 5, dels av namnda huvudaxel H. An inclined pin 6 is arranged with a longitudinal axis L forming an acute angle α with the main axis H. The inclined pin has a direction so that an engagement with rock intended cutting end 7 projects so that a surface area 8 thereof are located in direct connection to the said edge 5 'of said orifice portion 5, partly of said main shaft H.

Det snedstallda stiftet 6 kommer sAledes att verka centralt i det bergparti, i princip i form av en cylinderformig bergkropp, utgOrande vad som fare borrningen med borrkronan uppfyller det avsedda borrhalet. Det i denna kropp centralt belagna bergmaterialet kommer harvid att avverkas genom det snedstallda stiftet. Snedstallningen medfor att det snedstallda stiftets 6 rotparti kan placeras sá att spolkanalen 4 med fordel kan dras nara huvudaxeln H utan att integriteten av infastningen f5r det snedstallda stiftet 6 aventyras. The inclined pin 6 will thus act centrally in the rock portion, in principle in the form of a cylindrical rock body, constituting what is to be drilled. with the drill bit meets the intended drill tail. That in this body centrally coated rock material will then be felled through the inclined pin. The inclination means that the root portion of the inclined pin 6 can be placed so that the flushing channel 4 can advantageously be pulled close to the main axis H without the integrity of the mounting for the inclined pin 6 adventures.

Utever det snedstallda stiftet 6 uppvisar borrkronan 1 enligt uppfinningen en fOrsta uppsattning perifera stift 11, 77195 20120418 vilka är fordelade ytterst langst periferin av borrkronan och ar riktade med sina respektive langaxlar L' i divergerande riktningar sett i avverkningsriktningen A och en andra uppsattning mellanliggande stift 12, mellanliggande sett i en radiell led for borrkronan, vilka mellanliggande stift 12 är anordnade med sina langsaxlar L" vasentligen parallella med huvudaxeln H. In addition to the inclined pin 6, the drill bit 1 according to the invention has a first set of peripheral pins 11, 77195 20120418 which are distributed extremely along the periphery of the drill bit and are directed with their respective longitudinal axes L 'in diverging directions seen in the felling direction A and a second set of intermediate pins 12, intermediate seen in a radial joint for the drill bit, which intermediate pins 12 are arranged with their longitudinal axes L "substantially parallel to the major axis H.

Sett i avverkningsriktningen A är det snedstallda stiftet 6 belaget Aterdraget i forhallande till Atminstone den andra uppsattningen stift 12, vilket medfor att det snedstallda stiftet kommer att utsattas f8r reducerad belastning anvandning av borrkronan eftersom det kommer att krossa mindre mangd berg. Detta innebar i sin tur att omslipning av det snedstallda stiftet inte behavs alls eller atminstone inte behaver utforas lika ofta som vad fallet ar far stiften i den forsta respektive andra uppsattningen. Detta dr aven en fordel eftersom den sneda placeringen gor omslipning mer svarutford. Seen in the felling direction A, the oblique pin 6 is coated Aterdraget in relation to At least the other the set pin 12, which causes it to be inclined the pin will be subjected to reduced load use of the drill bit as it will crush less rock. This in turn meant that regrinding of the oblique pin did not behave at all or at least did not needs to be performed as often as is the case if the pins in it first and second set, respectively. This is also an advantage because the oblique placement makes regrinding more responsive.

Med fordel kan det snedstallda stiftet 6 normalt aven garas mindre an de ovriga stiften, i synnerhet om det utformas i enlighet med ovan namnda WO 2011/043717, vilket aven ar fordelaktigt far infastningen av detta snedstallda stift borrkronan. Advantageously, the inclined pin 6 can normally also be made smaller than the other pins, especially if it is designed in accordance with the above-mentioned WO 2011/043717, which also advantageously the fastening of this inclined pin gets the drill bit.

Av frontvyn i fig. 2 framgar mynningspartiets 5 langstrackta, eventuellt ovala form samt tva vasentligen radiellt forlOpande spolspAr 10 utgaende fran namnda mynningsparti 5 och strackande sig till periferin av borrkronan, varefter ej visade fortsattningsspolspar med axiellt farlopp ansluter. The front view in Fig. 2 shows the elongated, possibly oval shape of the mouth portion 5 and two substantially radially extending coil track 10 starting from the said orifice portion 5 and extending to the periphery of the drill bit, after which continuation coil pairs not shown with axial passage connect.

Ett plan genom linjen Al, vilket plan gar genom huvudaxeln H, bildar symmetriplan for det snedstallda stiftet, for spolkanalen 4 och for mynningspartiet 5 liksom generellt for borrkronan 1 i denna utforingsform av uppfinningen. 77195 20120418 11 Fig. 3a, 3b och 3c visar tre andra utforingsformer av en borrkrona enligt uppfinningen, vilka samtliga skiljer sig fran den i fig. 1 och 2 visade genom att mynningen 15 av spolkanalen ar utformad mer cirkular an vad fallet ãr vid borrkronan enligt fig. 1 och 2. Formen kan karaktariseras som "fylligt U-formad" med uppdragna andpartier sá att en inre kant 15 av mynningen 15 omsluter en stor del av det snedstallda stiftet 6 centralt runt huvudaxeln H. A plane through the line A1, which plane passes through the main axis H, forms the plane of symmetry of the inclined pin, for the flushing channel 4 and for the mouth portion 5 as well as generally for the drill bit 1 in this embodiment of the invention. 77195 20120418 11 Figs. 3a, 3b and 3c show three other embodiments of a drill bit according to the invention, all of which differ from that shown in Figs. 1 and 2 in that the mouth 15 of the flushing channel is formed more circularly than is the case with the drill bit according to Figs. 1 and 2. The shape can be characterized as "Fully U-shaped" with raised end portions so that an inner edge 15 of the mouth 15 encloses a large part of the inclined pin 6 centrally around the main axis H.

Vid utforingsformen i Fig 3a ãr det snedstallda stiftet 6 placerat sa att det med namnda ytomrade 8 befinner sig i direkt anslutning till och tangerande namnda huvudaxel H. In the embodiment in Fig. 3a it is inclined the pin 6 placed so that it is located with the said surface area 8 directly adjacent to and tangential to said major axis H.

Vid utforingsformen i Fig 3b ãr det snedstallda stiftet 6 placerat sá att det med namnda ytomrade 8 bef inner sig i anslutning till huvudaxeln H, pa ett avstand frail huvudaxeln som dr dimensionerat sá att vid anvandning av borrkronan i en for denna avsedd bergtyp stiftet 6 kommer att verka i ej avverkat material i enlighet med vad som diskuteras ovan. In the embodiment in Fig. 3b, the inclined pin 6 is placed so that it with said surface area 8 is located inside adjacent to the main axis H, at a distance frail the main shaft which is dimensioned so that when using the drill bit in a rock type intended for this, the pin 6 will operate in unmilled material in accordance with what is discussed above.

Vid utforingsformen i Fig 3c dr det snedstallda stiftet 6 placerat sa att det med namnda ytomrade 8 omsluter namnda huvudaxel H, d.v.s. sá att huvudaxeln H fOrlOper genom det snedstallda stiftet 6. In the embodiment in Fig. 3c, the oblique figure the pin 6 placed so that with the said surface area 8 it encloses the said main shaft H, i.e. saw that the main axis H passes through the inclined pin 6.

Vid utfOringsformen i Fig 3d ãr liksom vid utfaringsformen i Fig 3a det snedstallda stiftet 6 placerat sá att det med namnda ytomrade 8 bef inner sig i direkt anslutning till och tangerande namnda huvudaxel H. Darutover uppvisar borrkronan i Fig3d ett ytterligare snedstallt stift 6', vilket ãr placerat i anslutning till och nagot utskjutande Over en kant av mynningspartiet 5 av spolkanalen. Detta ytterligare snedstallda stift 6' ár fOretradesvis pa samma axiella niva som stiftet 6 men inte placerat i anslutning till huvudaxeln, som stiftet 6. Det ytterligare snedstallda stiftet 6' kan 77195 20120418 12 speciellt vid borrkronor av storre dimensioner bidra till god sanderdelningseffekt pa bergmaterial i ett centralt omrade, och darmed Oka livslangden far det snedstallda stiftet 6. Det utesluts inte att fler an ett ytterligare snedstallt stift ar fordelade kring mynningspartiet i borrkronans front och placerade pa ett liknande satt som stiftet 6'. In the embodiment in Fig. 3d is as in the embodiment in Fig. 3a the inclined pin 6 placed so that with said surface area 8 it is located in direct connection to and tangential to said main axis H. In addition, the drill bit in Fig. 3d has a further inclined pin 6 ', which is placed adjacent to and slightly projecting. edge of the mouth portion 5 of the flushing channel. This further Inclined pins 6 'are preferably at the same axial level as the pin 6 but not located adjacent to the main shaft, as the pin 6. The additional inclined pin 6' can 77195 20120418 12 especially with drill bits of larger dimensions contribute to a good sand splitting effect on rock material in a central area, and thus increase the service life of the inclined pin 6. It is not excluded that more than one additional inclined pin is distributed around the mouth portion in the front of the drill bit and placed in a similar way as the pin 6 '.

Fig. 4 visar borrkronan 1 i fig 1 i ett tankt driftlage verkande mot ett schematiskt illustrerat bergparti 13, for att illustrera att det snedstallda stiftet 6 ar Aterdraget i forhallande till de mellanliggande stiften 12. Fig. 4 shows the drill bit 1 in Fig. 1 in a tank operating layer acting against a schematically illustrated rock portion 13, to illustrate that the inclined pin 6 is Retraction in relation to the intermediate pins 12.

Betydelsen av detta har behandlats ovan. The significance of this has been discussed above.

Uppfinningen kan varieras mom ramen f6r de efterfoljande patentkraven och antalet stift ingaende i borrkronan kan varieras efter borrkronans storlek och efter anvandningsomrade for borrkronan. The invention can be varied within the scope of the following the requirements and the number of pins inserted in the drill bit can be varied according to the size of the drill bit and according to the area of use for the drill bit.

Det snedstallda stiftet kan med ferdel vara placerat pa ett avstAnd fran huvudaxeln, vilken ju car en rotationsaxel far borrkronan, och utgar den axel, kring vilken stiften, inklusive det snedstallda stiftet, beskriver en roterande rorelse i anvandning av borrkronan. The inclined pin can advantageously be placed at a distance from the main shaft, which of course a axis of rotation carries the drill bit, and extends the shaft around which the pin, including the oblique pin, describes a rotating movement in the use of the drill bit.

Sasom diskuteras ovan är foredraget detta avstAnd motsvarande till vidden av en krosszon, d.v.s. vidden, eller med andra ord djupet av en zon med krossat material, som krossas och darmed avverkas vid ett slag av borrkronan. Detta majliggor centrerad placering av mynningspartiet av spolkanalen utan att riskera att en kvarstaende icke krossad del av berget uppkommer, sAsom en skadlig central bergtapp, vilken skulle kunna aventyra funktionen och reducera effektiviteten av borrkronan och i synnerhet spolningen. As discussed above, preferably this distance corresponds to the width of a crushing zone, i.e. the width, or in other words the depth of a zone of crushed material, which is crushed and thus felled by a blow of the drill bit. This majliggor centered location of the estuary portion of the flushing channel without the risk of a remaining non-crushed part of the rock arising, such as a harmful central rock pin, which could jeopardize the function and reduce the efficiency of the drill bit and in particular the flushing.

Angivelsen cm placering av det snedstallda stiftet i direkt anslutning till huvudaxeln kan saledes relateras till att nAgot ytparti darav inte bor vara pi ett storre avstand fran huvudaxeln an djupet av namnda krosszon i berget, vilken 77195 20120418 13 alstras vid driften av borrkronan. Djupet av krosszonen beror av flera parametrar, av vilka som exempel kan namnas berghardhet och avgiven slagenergi. For normala forhallanden i medelhart berg kan normalt raknas med att krosszonens djup ar c:a 1,5 - 2 mm. Normalt bor darfor avstandet mellan huvudaxeln och mest narliggande ytparti av det snedstallda stiftet inte vasentligt Overstiga dessa varden. The indication cm location of the oblique pin in direct connection to the main axis can thus be related to the fact that some surface portion thereof should not be at a greater distance from the main axis than the depth of said crushing zone in the rock, which 77195 20120418 13 generated during the operation of the drill bit. The depth of the crushing zone depends on several parameters, of which rock hardness and delivered impact energy can be mentioned as examples. For normal conditions in medium-hard rock can normally be traced to the depth of the crushing zone c: a 1.5 - 2 mm. Normally, therefore, the distance between the main axis lives and most adjacent surface portion of the oblique pin does not substantially exceed these values.

Mindre flodesmotstand for spolfluid medfor behov av lagre spoltryck, vilket bl. a. leder till mindre friktionsfOrluster och reducerat pumpeffektbehov. Less river resistance for flushing fluid entails the need to store flushing pressure, which i.a. a. leads to smaller friction losses and reduced pump power requirements.

Tester med en borrkrona enligt uppfinningen har gett positiva resultat bade vad avser borrhastighet, vilken har kunnat 8kas med c:a 10%, och livslangd, vilken har kunnat 8kas med mer an 30% pa grund av minskat slitage, jamfOrt med en traditionell borrkrona med i 8vrigt motsvarande utformning. 77195 20120418 14 Tests with a drill bit according to the invention have given positive results both in terms of drilling speed, which has been able to be increased by about 10%, and service life, which has been able to be increased by more than 30% due to reduced wear, compared to a traditional drill bit with an otherwise corresponding design. 77195 20120418 14

Claims

Claims: 1. Drill bit (1) for striking rock drilling comprising a connecting part (2) for cooperation with a drill rod and a felling part (3) designed for engaging against rock and in a felling direction (A) with a plurality of frontally projecting pins in the form of rock processing inserts, said pins being distributed in radial direction as well as in rotational direction in relation to a main axis (H) f Or the drill bit, and wherein the drill bit has a frontal ± felling part opening flushing channel (4) for transporting flushing medium in a can central frontal area (C) of the felling section:

Said spool channel (4) opens with an edge (5 ') of an orifice portion (5) adjacent to said main shaft, and 2. an inclined pin (6) is arranged so that a longitudinal axis (L) forms the inclined pin an acute angle (a) with a longitudinal direction for the drill bit (1), and that a felling end (7) intended for engaging with rock of the inclined pin projects so that a surface area (8) of the felling end is adjacent to the said mouth portion (5), partly ndmnda main shaft (H).

Drill bit according to claim 1, characterized in that said mouth portion (5) is located substantially opposite the inclined pin (6) in relation to the main shaft (H).

Drill bit according to claim 1 or 2, characterized in that the longitudinal axis (L) of the inclined pin (6) forms an acute angle (a) with said main axis (H).

Drill bit according to claim 1, 2 or 3, characterized in that the inclined pin (6) emanates from a chamfered front surface portion (9) of the felling part (3).

Drill bit according to one of Claims 1 to 4, characterized in that, seen in the felling direction (A), the inclined pin (6) draws the coated retraction in relation to other pins (12) of the drill bit (1).

Drill bit according to any one of claims 1 - 5, characterized in that said acute angle (a) is between ° and 700 °.

Drill bit according to claim 6, characterized in that said acute angle (a) is between ° and °.

Drill bit according to claim 7, characterized in that said acute angle (a) is between ° and °.

Drill bit according to any one of claims 1 - 8, characterized in that the inclined pin (6) projects so that it with said surface area (8) is located at a distance from said main axis (H) which is dimensioned corresponding to a width of a related crushing zone arising from the use of the drill bit in a rock type intended for this.

Drill bit according to any one of claims 1 - 9, characterized in that the felling part (3) has a frontal at least one substantially radially extending coil pair (10) emanating from said mouth portion (5).

Drill bit according to any one of claims 1 - 10, characterized in that said orifice portion (5) consists of an elongated hall, in connection with which one longitudinal said surface area (8) of the inclined pin (6) is located. 77195 20120418 16

Drill bit according to any one of claims 1 - 10, characterized in that said mouth portion (5) consists of an oval, rounded half-man-shaped or full U-shaped hall.

Drill bit according to one of Claims 1 to 12, characterized by the flushing channel (4) extending with substantially the same cross-sectional area over its length.

Drill bit according to any one of claims 1 - 13, characterized in that the inclined pins (6) mentioned above have a first set of peripheral pins (11), which are directed in diverging directions, seen in the felling direction (A) and a second set, seen in a radial joint for the drill bit intermediate pins (12), which are arranged with their longitudinal axes substantially parallel to the main axis (H).

Drill bit according to one of Claims 1 to 14, characterized in that a plane (A1) through the main shaft forms a plane of symmetry for the inclined pin and the mouth portion.

Drill bit according to any one of claims 1 - 15, characterized in that at least one further inclined pin (6 ') is placed adjacent to an edge of the mouth portion (5).

A drill bit according to any one of claims 1 - 16, characterized by the flushing channel (4) after its length up to an outlet opening in a front surface of the drill bit has substantially the same cross-sectional area over its length as a cross-sectional area of a pinhole of the drill bit.

Drill bit according to claim 17, characterized by a relationship between the cross-sectional area (S) of the flushing channel (4) and a cross-sectional area (B) of a drill bit generated by the drill bit in operation at At least 0.05. 77195 20120418 N61 z _5 / 9E- g: v _5 / 1