CN102482918A - Drill bit - Google Patents

Abstract

The present invention relates to rock destruction tools, and more particularly, to roller cone drill bits having air drilling capability that may be used to drill high hardness rock. The drill bit comprising a body and rock breaking elements mounted on the body one inside the other by means of bearing supports, wherein the internally assembled rock breaking elements are positioned at an angle relative to the axis of the drill bit and the externally positioned rock breaking elements are positioned in opposite directions relative to the axis of the drill bit; increased service life, high efficiency and versatility are ensured by the following facts: the rock breaking elements are provided with replaceable spray nozzles made of wear resistant material provided with cutters made of a ferromanganese wolframite-cobalt based alloy, on top of which the bearing support of each rock breaking element is provided with means for adjusting the axial play value.

Description

Drill bit

The present invention relates to rock failure mechanism of rock instrument, more specifically, the present invention relates to have the rock bit of air boring ability.This instrument is holed to the rock of high rigidity and maximum hardness through surface mining during being used in the pit shaft drilling operation in mining and the gold mine industry.

Be known that rock bit has hobboing cutter, this hobboing cutter is installed on the leg axle through keeping ball bearing and two roller bearings, wherein two roller bearings all be taper and keep ball bearing between them.(USSR?Certificate?of?Authorship?No1229297，MIIK⁴?E?21?B?10/22，publ.07.05.1986，Bulletin?No17)。

This drill bit has following shortcoming:

1) the weight enabling capabilities that the common disadvantage that has a modern drill bit (especially those are used for drill bit that hard rock is holed) of conical hob is considered to the drill bit shank is not enough.The fabrication scheme of bearing supports that is known that a part (shank) of general tricone bit is: " roller-ball-roller " or " roller-sliding ball ".Even world-renowned bellwether company also makes such drill bit in the industry, wherein is loaded into allowable load on the drill bit shank and only equals to optimizing effectively the hole 60-70% of the size taked of hard rock.The main cause that is known that drill bit failures is fracture or the locking (its occupied fault surpass 80%) of the shank of one of hobboing cutter.For example, in 2007, for the boring of rock in the Krivoy Rog iron ore district, average drilling depth was 166 meters (according to Protodyakonov ratios, the stiffness factor f=16-19 of rock).Therefore, several times of application life that surpass the drill bit shank application life of the hard alloy cutting structure of drill bit.

2) bearing supports of a part (section) that has a tricone bit of hobboing cutter is applied to about 1/3rd load on the drill bit.Because the axis of each shank becomes about 37-39 ° angle with level, can be divided into radial component and axial component so be applied to a full payload on the shank.The radial component that is applied to the load on the support member is only kept by end and peripheral roller bearing, and correspondingly is distributed between them with 35 to 65% ratio.(Drill Bits.Digest.Publication 3.PalyiPA.Korneev K.E. " Depths " .1971, the 446th page).Each bearing supports (the especially bearing race on the axle) is with the limit bearing load of the metals capacity of axle, roller and hobboing cutter.

3) different very obvious in shank, bearing assembly and the hob design of the purpose drill bit that is soft rock, medium-hard rock and hard rock are holed makes even all is absolutely not for the standardization of the composite component of the drill bit of same size.This is the expensive real causes of rock bit.

4) axial component that is applied to the load on the bearing supports is variable and is negative value that this is to the not influence of rock failure mechanism of rock characteristic of drill bit.Its direction is along the axis of axle and being applied on the support member above 60% full payload.Thrust load in tradition " roller-ball-roller " support member is applied by two-way maintenance ball bearing.It keeps thrust load, the direction of the direction pointed end bearing of this thrust load and opposite direction: the direction of the base portion of axle.The load of both sides causes keeping ball bearing to wear and tear fast and causes big end-play.Be known that cylindrical roller deviation occurs with respect to bearing race when having the play of 3-5mm in the support member, and the support member generation is stuck, wherein the load region angle of conical roller bearing significantly descends.

It is known that drill bit opens wide bearing supports, and the periphery that it has the shank that has axle, hobboing cutter, install near the base portion of axle keeps conical roller bearing and end tapered roller bearing, and hobboing cutter is arranged on this end tapered roller bearing.Therefore, peripheral bearing be fixed on by turn that axle is gone up and the body of hobboing cutter in.End bearing is installed on the axle, so that can freely rotate along axial (longitudinally), and it is through the shoulder of disc spring backup axle.

This modification of support member comprises conical roller bearing, cylindrical roller bearings and roller thrust block.(PCT International Application No. WO 2005/021923A1, MIIK7:E 21B 10/22.International Publication day: on March 10th, 2005).

This similar item of drill bit has following shortcoming:

1) producer of drill bit similar item is not included in traditional two-way maintenance ball bearing in the design concept of support member by error; Keep (imagination) function that substitutes of bearing to concentrate on the peripheral conical roller bearing, only can tackle the thrust load of a side although be known that the latter.The support member design concept of drill bit similar item (Fig. 1,2 of the accompanying drawing of PCT application WO2005/021923) comprises the theory of the single conical roller bearing of typical 7000 types.According to GOST 333-71 (R.D.Beyzelman, B.V.Tsypkin, L.Ya.Perel.Bearings.Digest.Publication b, M. " MechanicalEngineerin ", 1975, p.52-53.Also be called as Digest), 7000 types are main a kind of bearings.The contact angle that 7000 profile shafts hold is a=10-17 °.

Single conical roller bearing only can be tackled the thrust load of a side.Allow to be loaded into the thrust load that 7000 profile shafts hold and to surpass 70% of untapped permission radial load.As stated, about 35% of the radial load on the end roller bearing maintenance support member of traditional tricone bit.This value balance the strength of materials limit of bearing race and bearing roller.Additional thrust load possibly become the reason of end bearing critical failure and the locking of hobboing cutter shank, and the value of this additional thrust load is above 2-2.5 times of the radial component of the end bearing load that allows.

2) inner ring of the end bearing of drill bit similar item is installed on the axle, so that can be along axis (spontaneously) rotation randomly of axle, this comprises the cylindrical shoulder at the place, side of peripheral bearing.Be arranged on preliminary axial tensile force and power sealing that disc spring between the inner ring of shoulder and end bearing is rendered as the element of guaranteeing two roller bearings, this claims and has eliminated the possibility of play (gap) in the support member.

Yet, the interactional kinetostatics analysis of the parts of the support member of drill bit similar item has been shown following situation:

A) when the hobboing cutter body can not move (body of hobboing cutter is by the absolute rigidity surface support) routinely, the radial component that is applied to the load on the axle (shank) is distributed between two roller bearings (Fig. 1 of PCT application WO2005/021923).Through the cylindrical shoulder on the axle, thrust load is applied on the disc spring fully and makes it have great defective.Because all elements of end roller bearing all have been enclosed in each other and have sealed with the hobboing cutter body,, the direction of motion that in support member, only can obtain passes through of the vertical rotation of the inner ring hole of end bearing along the direction at hobboing cutter top so being axle.

Aspect this, the inner ring of peripheral conical roller bearing will move along the direction at hobboing cutter top with conical roller, retainer and axle.Therefore, imagination keeps peripheral roller bearing to open, and reason is that the roller that is positioned at the axis top of axle no longer can contact with the outer ring.So, quite a few times of particular values that end-play surpass to allow (Digest, p.168, table 14).As a result, the load region angle of bearing significantly reduces (decline 60-90 ° value rather than best 170-180 ° value), and the pressure that imposes on bearing element possibly surpass the value that allows reluctantly.

B) when axle can not move routinely, the axial component that is applied to the load on the hobboing cutter points on the direction of its base portion along the axis of axle.Through outer ring, roller and the inner ring of hobboing cutter body, end bearing, thrust load is applied on the disc spring fully and makes it have great defective.So will move along the direction of axle base portion in the outer ring of the body of hobboing cutter, end bearing, disc spring and the peripheral conical roller bearing of (imagination) maintenance, the value of motion equals the size of disc spring distortion.(imagination keeps), peripheral roller bearing was opened once more, its end-play fast rise, and the load region angle of bearing significantly reduces.Consider when the load on the support member of the hobboing cutter that is applied to drill bit be boring and when under any circumstance repeating, in the support member additional axially and radial vibration will have totally unfavorable influence to the application life of drill bit.Here it is is intended to will minimize and strictly limit the definite reason in radial and axial gap in any support member.

The major defect of the support member design of drill bit similar item is that the phantom perimeter in the reality keeps conical roller bearing can any influence not arranged to the end-play value in the support member.

3) bearing supports of the drill bit of another type (comprising a single conical roller bearing, a roller bearing and the ball thrust bearing with cylindrical roller) similar item (Fig. 2 of PCT application WO2005/021923) does not meet the simple and practical rule of taper and thrust bearing, particularly:

A) single conical roller bearing should make up at least one pair of (Digest, p.53 the 2nd section in support member; P.169, Fig. 3-b, 3-d).

B) how thrust bearing should be installed at its thrust circle and have some uniqueness on the axle and aspect in the body.For example, need utilize standard tensioning level that a thrust circle is fixedly mounted on the axle, and should be with another thrust circle of the lax level assembling of standard, this lax level equals 0.2-0.4mm.Guarantee to relax and be the wide 0.2-0.4mm of the diameter of the interior diameter ratio shaft of the second thrust circle.Be used to install the wide 0.5-1mm of external diameter that the diameter of the groove of second circle should the specific thrust bearing in the body.On its top, GOST with " circle-axle " to and " circle-body " minimum of separated directed thrust directed thrust surfaces is allowed to comprise mandatory requirement (Digest, p.520-523 table 19) aspect the width.

The producer of drill bit similar item has ignored all these and has required (PCT to be applied for the accompanying drawing of WO2005/021923, Fig. 2).For example, they are installed in axle with a thrust circle with end-play and go up (rotatably installing), and the outside that another circle and rolling element are arranged in spool with retainer.Refused the regulation that requires width of directed thrust directed thrust surfaces of the circle of relevant ball thrust bearing, they use the directed thrust directed thrust surfaces of disc spring end (linear contact) as the thrust circle.

C) phantom perimeter keeps conical roller bearing to be arranged in the body of hobboing cutter by screw-thread bush, but the purpose of thread connection is not to support dynamic radial load.For this reason, when needed, will be fixedly mounted in cylindrical liner in the main body, cup etc. with bearing and use (for example: Digest, p.380 Fig. 2 and p.381 Fig. 3) with the radially tensioning of cylindrical contact surface.

The support member of expression does not satisfy the simple requirement of relevant drill bit support member design among Fig. 1 and 2 (PCT applies for WO2005/021923), and reason is that the principle element of guaranteeing the restriction of end-play value is not provided.

Immediate similar item (being prototype) is considered to drill bit; It comprises body and rock failure mechanism of rock element; Wherein rock failure mechanism of rock element is positioned at another inboard mode by means of bearing supports with one and is installed on the body; Wherein be assembled in inner rock failure mechanism of rock element locate angledly, locate (USSR Certificate of Authorship No 512282, MIIK2:E 21 B 9/08 with respect to the axis of drill bit along opposite direction and be in outside rock failure mechanism of rock element with respect to the axis of drill bit; Publ.30.04.1976, Bulletin No 16).

The drill bit prototype has following shortcoming:

1) bearing supports of drill bit is provided as integral type, and the mode that in tricone bit, has with them is identical, and they are provided with the maintenance ball bearing, keeps ball bearing to be installed in the support member by means of getting into hole and bulb stopper.Such maintenance bearing does not provide any possibility of prestrain or Current Control on the end-play value.

2) technology of the bearing race product on the body in the cavity of hobboing cutter is very complicated and consuming time, just as tricone bit institute based on technological.

3) the same with other drill bit, differ widely the application life of the critical piece of drill bit prototype (body, bearing supports and hobboing cutter equipment) each other.For example, from the test operation of the drill bit sample of trial batch the time, definite is, for first, the application life of bearing supports several times the application life of wolframite-cobalt rock failure mechanism of rock element.This is possible, and reason is that the angle in the bearing load district in the support member of drill bit prototype equals 360 °, but it becomes and is not more than 160-175 ° in tricone bit after concurrent testing.

When the working surface wearing and tearing of the rock failure mechanism of rock element of the drill bit prototype that is provided with the hard alloy cutting knife to 100% the time, the wearing and tearing of drill body are not more than 25%, and the wearing and tearing of bearing supports are 35%.The drill bit of this half wearing and tearing can not repaired, and reason is that the design of drill bit prototype does not provide the possibility that changes or restore the parts of wearing and tearing.

The objective of the invention is to increase fully application life, its efficient and the versatility of drill bit.

The objective of the invention is to; This drill bit comprises body and rock failure mechanism of rock element; This rock failure mechanism of rock element is positioned at another inboard mode by means of bearing supports with one and is installed on the body; Wherein be assembled in inner rock failure mechanism of rock element locate angledly, be positioned at outside rock failure mechanism of rock element and locate along opposite direction, according to the present invention with respect to the axis of drill bit with respect to the axis of drill bit; Rock failure mechanism of rock element is provided as the removable injection nozzle of being processed by high-abrasive material (matrix); And this injection nozzle is provided with the cutting knife of being processed by stiff materials, and on the top of rock failure mechanism of rock element, the bearing supports of each rock failure mechanism of rock element is provided with the device that is used to regulate end-play value (or preliminary tensioning).

Advantage below this design of drill bit provides:

-use removable injection nozzle (matrix) as composite component, it can be removed and through frayed apace, thereby allows to keep the reliable operation of drill bit, weares and teares fully up to all elements (body, hobboing cutter and bearing supports);

-use removable injection nozzle, i.e. the removable equipment of hobboing cutter, its can be as required maybe difference on the hard alloy cutting knife quantity of (comprising the most advanced and sophisticated cutting knife of rhombus that be), size and dimension, guarantee the standardization of drill bit.So, the said drill bit that purpose is the rock of soft rock, medium-hard rock, hard rock and maximum hardness is holed with definite size maybe: only different on the material of the cutting knife of removable injection nozzle equipment and geometry.

-removable injection nozzle allows to use cheap material to be used for the body of drill bit and the body part of rock failure mechanism of rock element, and wherein removable injection nozzle can be processed by glass hard steel and the alloy with particular characteristics such as hardness, abrasion resistancies;

Wear-resistant equipment of-rock failure mechanism of rock element is with the thrust load of only tackling a useful side and solid bearing supports with 3600 load angles; In 3-5 times of the application life of permission increase drill bit, reason is the cost that only needs other unit of manufacturing equipment.

Being used in the support member of-rock failure mechanism of rock element, the device of regulating end-play or preliminary tensioning allowed to abandon that Global Access uses selects the rolling element (this is unique) that divides into groups according to the real size of bearing race with in the hobboing cutter cavity on the axle for each part of drill bit.

-can the standardization drill bit the manufacturing of some parts: shank, hobboing cutter, bearing or rolling element and retainer.Thus, the manufacturing of drill bit and assembling are enough to simplify and cheapness.

Describe three possible modification making drill bit of the present invention by accompanying drawing, that is: the front section of the drill bit with separable ball bearing has been shown among Fig. 1; The front section of the drill bit with separable roller bearing has been shown among Fig. 2; The front section of the drill bit with separable support member has been shown among Fig. 3, and this support member comprises the bearing that typically is provided with outer ring and inner ring, rolling element and retainer; The photography view of the experimental model (modification that promptly has central nozzle) of drill bit has been shown among Fig. 4.

Drill bit (Fig. 1) comprising: have the body 1 and rock failure mechanism of rock element of removing mouth 2: rock failure mechanism of rock element comprises the inside rock failure mechanism of rock element of processing according to preceding hobboing cutter 3 and outside rock failure mechanism of rock element 4.Rock failure mechanism of rock element is installed on the body by means of the separable bearing assembly (support member) 5 and 6 that is made up of ball thrust bearing.Since will be through frayed, the operate portions of rock failure mechanism of rock element is provided with removable injection nozzle 7 and 8.This injection nozzle is processed and is provided with the cutting knife of being processed by stiff materials (for example based on the alloy of wolframite-cobalt or based on super-hard compound material synthetic and natural diamond) 9 by high-abrasive material.Injection nozzle utilization device (for example utilizing screw) commonly used is fixed on the end of rock failure mechanism of rock element.

The top ball thrust bearing of the support member of rock failure mechanism of rock element 3 is provided with the end-play value that is for example realized by end plate and bolt that keepscircle 10 and adjusting device 11, this adjusting device to be used for the adjustable support part.The ball bearing support member 5 of outside rock failure mechanism of rock element 4 is provided with and keepscircle 12 and the screw-typetop cover 13 that is used for the end-play value of adjustable support part.This top cover has sealing ring.

Shown in drill bit modified example further (Fig. 2) comprise having and remove mouthfuls 2 body and rock failure mechanism of rock element 3 and 4 that rock failure mechanism of rock element 3 and 4 is installed on the body by means of the bearing supports that is made up of the conical roller bearing withretainer 14 and 15.Bearing supports 14,15 is provided with thedevice 16 and 17 that is used to regulate the end-play value.This device 17 makes support member replaceable.

Shown in another modified example (Fig. 3) of drill bit comprise having and remove mouthfuls 2 body 1 and rock failure mechanism of rock element 3 and 4; Rock failure mechanism of rock element 3 and 4 is installed on the body by means of the bearing supports that is made up oftypical bearing 18 and 19, and said bearing is: journal bearing or tappered rolling bearing, conical roller bearing etc. with outer ring and inner ring, rolling element and retainer.For example, the ball bearing of following type: 0000 GOST 8338-93; 60000 with 80000GOST 7242-85; 1000 GOST 5720-75; 3000 GOST 8545-78; 6000 GOST 831-90; 7000GOST 333-94; 8000 GOST 6874-82 etc.

Rock failure mechanism of rock element is provided with the removable injection nozzle of being processed by high-abrasive material.The operate portions of injection nozzle is equipped with the cutting knife of being processed by stiff materials (for example based on the alloy of wolframite-cobalt or based on super-hard compound material synthetic and natural diamond) 9.The end tip of cutting knife can be equipped with diamond.

Drill bit is worked as follows.

The body of drill bit is connected to the drilling rod of rig.Have the rotary drilling-head of setting end-play and be sent to the down-hole.Simultaneously, air is transferred through removing mouth 2 under pressure.Be deep in the surface in shaft bottom up to cutting knife 9, rock failure mechanism of rock element contacts with rock and overturns in the down-hole owing to the rotation of drill body 1.The contact area of rock failure mechanism of rock element is positioned on the relative side with respect to the axis of down-hole, and this has eliminated the possibility of drill bit with respect to the radial axis vibration of well.The motion path of injection nozzle 7 and each cutting knife 9 of 8 is a waveform.So through destroying and grinding definite lithosphere, cutting knife 9 cuts the local part of down-hole in order.In annular space, compressed air stream is the drilling mud downhole surface of blowing off, and it is transported on the ground surface.The outside rock failure mechanism of rock element of taper makes its possibility that contacts with hole wall minimum.Thus, reduced the operation torque of the motor on the axle and minimize the heating of bit part.

The workbench test of the experimental model of drill bit and the test (for example, in Fig. 4) under the natural conditions have confirmed the high efficiency that these drill bits are compared with traditional tricone bit, particularly:

-owing to the load that can improve on the drill bit makes the mechanical speed of boring increase 2-2.5 doubly;

-make the required torque value of motor reduce 2-3 doubly;

-make increase 10-45 doubly the application life of bit bearing support member owing to support member middle (center) bearing load region angle being increased to 360 °;

-make increase 3-5 doubly application life of hard alloy cutting equipment of rock failure mechanism of rock element owing to having changed angle that motion path and cutting knife get into rock;

-owing to making, the removable apparatus assembly of introducing increases 4-5 the application life of drill bit self doubly.

Claims (1)

1. drill bit; It comprises body and rock failure mechanism of rock element; Said rock failure mechanism of rock element is positioned at another inboard mode by means of bearing supports with one and is installed on the body; Wherein be assembled in inner rock failure mechanism of rock element locate angledly, be positioned at outside rock failure mechanism of rock element and locate along opposite direction, it is characterized in that with respect to the axis of drill bit with respect to the axis of drill bit; Rock failure mechanism of rock element is provided with the removable injection nozzle of being processed by high-abrasive material (matrix); And this injection nozzle is provided with the cutting knife of being processed by stiff materials, and on the top of said rock failure mechanism of rock element, the bearing supports of each rock failure mechanism of rock element is equipped with the device that is used to regulate end-play value (or preliminary tensioning).

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