Abstract
A tool component comprising a wear part covered at least in part by a connection member, the wear part having a specified hardness and the connection member being a metal or alloy, and the wear part comprising a surface that includes one or more depressions or projections therefrom, and the connection member having been pressed against that surface so that at least the surface of the connection member that faces the wear part surface follows the profile of the wear part, whereby relative movement between the wear part and connection member is substantially prevented. The metal or alloy connection member may be readily attached to a tool body for example by brazing of the like. The wear part may comprise a material that is not readily brazeable, for example a ceramic material or a cermet or a superhard material or a composite of such materials.
Claims
1. A tool component comprising a wear part that is covered at least in part by a connection member, the wear part having a hardness of at least 15 GPa and comprising a ceramic material, a cermet material, or a superhard material or a composite of a ceramic and a superhard material, or a cermet and a superhard material, and the connection member comprises a metal or alloy, having a hardness less than 15 GPa, the connection member providing a layer over at least part of the wear part, the ratio of the thickness of the connection member to the thickness of the wear part underlying it measured at any point being at most 1:10, the wear part comprising a surface that includes one or more depressions therein and/or projections therefrom, and at least part of the connection member having been pressed against at least part of the surface of the wear part that includes the depressions or projections, such that a surface of the connection member that faces a surface of the wear part follows the profile of the said part of the surface of the wear part against which it has been pressed, whereby the surfaces of the wear part and the connection member are co-operatively shaped such that relative movement between the two parts is substantially prevented at least during operation of the tool component.
2. A tool component comprising a wear part that is covered at least in part by a connection member, the wear part having a hardness of at least 15 GPa and comprising a ceramic material, a cermet material, or a superhard material or a composite of a ceramic and a superhard material, or a cermet and a superhard material, and the connection member is made from a metal or alloy, having a hardness less than 15 GPa, the connection member providing a layer over at least part of the wear part, the thickness of the connection member being at most 6 mm, the wear part comprising a surface that includes one or more depressions therein and/or projections therefrom, and at least part of the connection member having been pressed against at least part of the surface of the wear part that includes the depressions or projections, such that a surface of the connection member follows the profile of the said part of the surface of the wear part against which it has been pressed, whereby the surfaces of the wear part and the connection member are co-operatively shaped such that relative movement between the two parts is substantially at least during operation of the tool component.
3. A tool component according to claim 1 or 2, wherein the said depressions and/or projections comprise dimples or nipples, grooves or ridges.
4. A tool component according to claim 1 or 2 or 3 wherein the connection member is in the form of a sheet.
5. A tool component according to claim 1 or 2 or 3, wherein the connection member is in the form of a cylinder open at both ends, or partially or fully closed at one end.
6. A tool component according to any preceding claim, wherein the wear part has a regular cross section or an irregular cross section and/or round sides or flat sides.
7. A tool component according to any preceding claim, wherein the wear part is substantially cylindrical, and includes one or more annular grooves extending around the cylindrical part.
8. A tool component according to claim 7, wherein the connection member is substantially cup shaped, the base of the cup seating against the base of the cylindrical wear part, and the sides of the cup extending at least part way up the cylindrical wear part, and covering and following the profile of the said annular grooves therein.
9. A tool component according to claim 8, wherein cup shaped connection member comprises a metal or alloy that has been drawn around the wear part, and the sides of the cup have been isostatically pressed into contact with the curved sides of the wear part to follow the profile of the annular grooves therein.
10. A tool component according to any preceding claim, wherein the connection member is shaped to follow the profile of the wear part over at least 10% of the surface of the wear part.
11. A tool component according to any preceding claim, wherein not only the surface of the connection member that faces the wear part follows the profile of the wear part but also the opposed surface of the connection member.
12. A tool comprising a tool component according to any preceding claim secured within a tool body via the connection member.
13. A tool according to claim 12 in which the said wear part of the tool component is a pick and the said tool body of the tool is a pick body.
14. A tool according to claim 12 or 13, wherein the tool body is made from a metal or alloy, and the metal or alloy connection member is fixed to the tool metal or alloy tool body by welding, brazing or soldering.
15. A tool component according to any of claims 1 to 11, wherein the wear part is the form of an annular ring, the annular ring having curved outer and inner surfaces and two substantially flat end faces.
16. A tool component according to claim 15, wherein the connection member is also in the form of an annular ring, the annular connection member surrounding the annular wear part, or vice versa.
17. A tool component according to claim 16, wherein the annular connection member has two end faces and comprises flanges extending from one or both end faces thereof at least part way over the respective end face(s) of the annular wear part.
18. A tool component according to claim 17, wherein the first connection member comprises a flange extending from one end face thereof at least part way over the respective end face of the annular wear part, and a second annular member, a mounting member, is provided to sandwich the first connection member between itself and the wear part, the mounting member comprising a flange extending from one end face thereof at least part way over the other end face of the annular wear part.
19. A tool component according to any of claims 14 to 18, wherein the said surfaces of the wear part and the connection member each include one or more grooves or projections in the outer or inner surface of the annular rings.
20. A tool component according to claim 19, wherein the grooves or projections extend longitudinally at least part way between the end faces of the annular rings, or extend at an angle to that longitudinal direction, or extend circumferentially around the annular rings.
21. A tool component according to any of claims 15 to 20 secured within a metal, alloy, carbide or cemented carbide tool body, the wear part of the tool component being a bearing, and the connection member of the tool component comprising a metal or alloy that is secured within the metal or alloy tool body by welding, brazing or soldering.
22. A tool component according to any preceding claim, wherein the wear part comprises a superhard/ceramic composite material, and the superhard component is diamond material.
23. A tool component according to any preceding claim, wherein the wear part comprises a superhard/ceramic composite material, the ceramic component being silicon carbide.
24. A tool component according to claim 1 which is a nozzle insert containing a bore for fluid.
25. A tool component which is a nozzle insert according to claim 24 wherein the wear part provides a core section adjacent the fluid bore, and the connection member provides an intermediate layer between the nozzle core and an outer metal housing component surrounding the core.
26. A tool component which is a nozzle insert according to claim 25 wherein the wear part is frustoconical in shape, the tip of the frustocone being positioned at the outlet end of the nozzle.
27. A tool component which is a nozzle insert according to claim 26, wherein the wear part core is substantially cylindrical in shape, with an annular flange extending radially outward therefrom, the flange being adjacent the inlet end of the nozzle.
28. A tool component which is a nozzle according to any of claims 24-27, wherein the said surfaces of the wear part and the connection member each include one or more depressions and/or projections therefrom, the depressions and/or projections from the said surface of the connection member co-operating with the said depressions and/or projections from the said surface of the wear part.
29. A tool component according to any of claims 1-11 or 15-28, wherein the connection member comprises a flange, and/or another member other than the wear part that is secured to the connection member comprises a flange, said flange(s) being for mechanical attachment to a tool body.
30. A method of making a tool component by joining (i) a wear part having a hardness of at least 15 GPa and comprising a ceramic material or a superhard material or a composite of a ceramic and a superhard material and comprising a surface that includes one or more depressions therein and/or projections therefrom, to (ii) a connection member comprising a metal or alloy having a hardness less than 15 GPa; the joining being carried out by pressing the metal connection member against the wear part, so that the connection member provides a layer over at least part of the wear part, the ratio of the thickness of the connection member to the thickness of the wear part underlying it measured at any point being at most 1:10, at least part of the connection member having been pressed against at least part of the surface of the wear part that includes the depressions or projections, such that a surface of the connection member that faces a surface of the wear part follows the profile of the said part of the surface of the wear part against which it has been pressed, whereby the surfaces of the wear part and the connection member are co-operatively shaped such that relative movement between the two parts is substantially at least during operation of the tool component.
31. A method according to claim 30, comprising the additional step of brazing, welding or soldering the connection member to a tool body, and thereby securing the wear part to the tool body.
32. A segmented tool component each segment of which comprises a tool component according to any of claims 1-29, each segment comprising a wear part and a connection member arranged relative to each other in the manner defined in any of claims 1-29, and the connection members of adjacent segments being secured to each other, thereby securing said wear parts of adjacent segments to each other.
33. A segmented tool component according to claim 32 which is a nozzle in which the segments are arranged end to along the axis of the nozzle.
34. A segmented tool component according to claim 32 which is a nozzle in which the segments are arranged side by side around the axis of the nozzle.
35. A method according to claim 29 or 30 of making a tool component, said tool component being segmented, each segment comprising a wear part and a connection member arranged relative to each other in the manner defined in any of the preceding claims, the method additionally comprising securing connection members of adjacent segments to each other, thereby securing said wear parts of adjacent segments to each other.
Description
SPECIFIC EMBODIMENTS/EXAMPLES
[0057] Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:
[0058] FIG. 1 is a side view, partly in section of a tool component according to the invention, the tool component being a pick (a wear part) in combination with a connection layer, and the tool component being inserted within a pick body, the wear part of the tool component being secured to the tool body by means of the connection member of the tool component with a braze layer;
[0059] FIG. 2a is a perspective view of the pick shown in FIG. 1;
[0060] FIG. 2b is a perspective view or the tool component of FIG. 1 2b showing the mechanical interlocking of the connection member with the pick;
[0061] FIG. 2c is a partially sectioned view of the tool component of FIG. 1 and FIG. 2b secured within a tool body by means of a braze layer;
[0062] FIG. 3 is a partly sectioned view showing an alternative embodiment of pick;
[0063] FIG. 4a is a perspective view of a bearing and connection member for the bearing;
[0064] FIG. 4b is a perspective view of the bearing and connection member of FIG. 4a brazed to an optional second annular metal or alloy member (a mounting member);
[0065] FIG. 4c is a plan sectional view of the bearing connection member and annular steel outer member of FIG. 4b;
[0066] FIG. 4d is a cross-sectional view taken along A-A f FIG. 4c;
[0067] FIGS. 4e and 4f, 4g and 4h, 4i and 4j, 4k and 4l, 4m and 4n, 4o and 4p, 4q and 4r are for each pair of figures, plan and side view respectively of possible alternative profiles to that shown in FIGS. 4a to 4d as examples for bearings, mechanical seals, picks and nozzles etc;
[0068] FIG. 5a is a perspective view of an inside-out version of the bearing of FIGS. 4a to 4d;
[0069] FIG. 5b shows the bearing of FIG. 5a in plan sectional view, with an optional second annular metal or alloy member (mounting member) shown to the right side of the Figure;
[0070] FIG. 5c is a cross sectional view through the left option of FIG. 5b, without the optional second annular metal or alloy member (mounting member;
[0071] FIG. 5d is a cross sectional view through the right option of FIG. 5b, with optional second annular metal or alloy member (mounting member) in place;
[0072] FIG. 6 is a side sectional view of two bearings similar to FIG. 4a-4d, one of relatively large diameter, and the other of a relatively smaller diameter;
[0073] FIG. 7 is a side sectional view through two bearings of the type shown in FIGS. 5a to 5d;
[0074] FIG. 8a is an end view of a plurality of SCD wear parts in a thrust bearing mounted in a ring around a metal housing part;
[0075] FIG. 8b is a sectional view taken along line B-B of FIG. 8a;
[0076] FIG. 8c is an enlarged sectional view of the circled portion of FIG. 8b;
[0077] FIGS. 9, and 10 are side sectional views of a nozzle inserts according to the invention;
[0078] FIG. 11 is a cross sectional view through a mechanical seal arrangement showing two tool components according to the invention held within respective tool holders and arranged to be urged against each other;
[0079] FIG. 12 is an enlarged sectional view through the circled part C of FIG. 13;
[0080] FIGS. 13a to 13c are perspective views which show sequential steps in joining tool components to each other to make a segmented larger flat tool component;
[0081] FIGS. 14a and 14b are sectional views through tool components joined to each other to make a variety of segmented nozzle tool components; and
[0082] FIG. 15 is a perspective view showing means of attachment of a cutting drill tool prepared for fitment into a drill shank.
[0083] FIG. 1 shows a tool component according to the invention comprising a wear part and a connection member. The wear part is a SCD pick 2 and the connection member is a steel cup 10. The pick 2 is held via connection member steel cup 10 within a metallic pick body 13. The steel cup 10 is secured to the metallic pick body 13 by a braze alloy 15. The SCD pick 2 is secured to the steel cup 10 by virtue of their co-operating shapes as described in more detail later.
[0084] FIGS. 2a and 2b show sequential stages in the manufacture of the tool component comprising pick 2 and steel cup 10, and FIG. 2c shows the method of securement of the pick 2 within the pick body 13 via steel cup 10.
[0085] The pick 2 is generally cylindrical, with a substantially pointed tip 3. It has an anchor portion 6. The anchor portion 6 includes two annular grooves 8, longitudinally spaced from each other. The diameter of the substantially cylindrical pick 2 is approximately 15 mm. The pick 2 comprises SCD material that is a composite of diamond and silicon carbide. The SCD material may be formed in its green state into a generally cylindrical shape (with pointed tip 3) and then the annular grooves 8 may be machined into the green SCD body. The grooves may be up to 2 mm in depth. The grooved part may then sintered.
[0086] FIG. 2b shows the SCD pick 2 of FIG. 2a with a connection member 10 positioned around the pick 2. The connection member 10 is in the form of a cup of 0.2 mm thick mild steel 10 that has been drawn onto the SCD pick 2 so that the base of the cup is in contact with the base of the anchor portion 6 of the pick 2, and the sides of the cup extend over the sides of the pick 2 part way towards the tip 3 of the pick 2. The sides of the cup 10 have then been CIPed (cold isostatically pressed) into place around the anchor portion 6 of pick 2, so that the base of the cup 10 is in contact with the anchor portion 6 of pick 2, and the sides of the cup 10 extend up around the sides of anchor portion 6 of pick 2, and extend longitudinally beyond the annular grooves 8 in pick 2. The sides of the cup 10 follow the profile of the pick 2, forming co-operating grooves 12 adjacent to the grooves 8 in the pick 2. The thickness of the CIPed steel cup 10 is approximately 0.2 mm at all points. There is no specific chemical bond between the CIPed steel cup 10 and the SCD pick 2, but because of the co-operating profiles of the pick 2 and the CIPed steel cup 10, there is no relative movement between the pick 2 and the CIPed steel cup 10 in a direction longitudinally of the substantially cylindrical pick 2. Relative rotation between the pick 2 and the steel cup 10 could occur in this embodiment, but alternative designs are envisaged that could prevent such rotation, if desired.
[0087] The ClPing process or any alternative possible isostatic pressing process advantageously applies a substantial uniform force in all inward directions onto the SCD pick 2. Since the cup 10 is made from mild steel a low force is required to CIP it into place to follow the profile of the SCD pick 2. Also since the cup 10 is made from mild steel it is ductile and hence there is no residual stress in the cup 10, and little to no residual stress on the pick 2.
[0088] FIG. 2c shows the pick 2 and steel cup 10 of FIG. 2b secured within the metallic pick body 13. The CIPed cup 10 surrounding the SCD pick 2 has been secured to the metal pick body 13 by brazing in a conventional manner. A braze alloy 15 is inserted between the pick body 13 and the steel cup 10 in a conventional way and is shown joining the steel cup 10 to the pick body 13. The braze insert 15 is typically about 0.1 mm in thickness The braze insert 15 advantageously absorbs energy, acting as a cushion, since the braze 15 is typically ductile. This advantageously improves the impact resistance of the secured SCD pick 2. Furthermore the braze layer 15 may be different thicknesses to allow for some variation in the dimensions of the pick 2. For example the pick may typically have a dimensional diameter tolerance of about 0.2 mm, and this can be accommodated by using different braze thicknesses. The braze dimensional tolerance also facilitates bonding to uneven surfaces. Furthermore the braze puts the SCD pick 2 into some compression (though not so great as would be the case with a shrink fitment). Some compression may be advantageous since SCD materials typically have better compressive strength than tensile strength, so the slight compression means the SCD component is less likely to be subjected to any, or significant, tensile stresses during operation.
[0089] Push off testing (shear stress assessment) was carried out to ascertain the strength of attachment achieved using the configuration illustrated in FIG. 2c, and an average value of shear stress (averaged over 6 samples) of about 240 MPa was achieved. Actual shear stress values for each of the samples measured were 260, 172, 180, 252, 255 and 312 MPa. This value of 240 MPa is significantly higher (more than three times higher) than the shear stress expected by the person skilled in the art for simple adhesive attachment of an SCD pick into the tool body.
[0090] FIG. 3 shows an alternative embodiment of pick 2 according to the invention. The pick 2 comprises SCD material as before. A CIPed steel cup 10 surrounds pick 2, and the pick 2 and co-operating steel cup 10 each have co-operating annular grooves 8, 12 respectively. The connection member cup 10 has flanges 11 extending at its top radially outward. These are for connection within a pick body (not shown). The SCD pick 2 and the steel cup 10 also have a plurality of co-operating grooves 19 along their bases, extending radially. These grooves substantially prevent relative rotation between the pick 2 and the connection member steel cup 10.
[0091] Other variations of co-operating formations in the surfaces of the SCD pick 2 and the connection member 10 other than the annular grooves shown are also envisaged, including but not limited to longitudinal grooves part way or the whole way along the length of the SCD pick 2, angled grooves, ridges, dimples, depressions, screw thread orientations and the like.
[0092] The arrangement shown in FIGS. 1-3 allows an SCD pick, or a carbide pick, which are known to be difficult to bond to other materials (for example to metals) by conventional methods (for example brazing, soldering, welding, friction welding, ultrasonic bonding, or shrink fitting) to be securely fastened within a metal or carbide pick body 13, via the connection member steel cup 10, the connection member steel cup 10 being: (a) mechanically secured, but not surface-bonded to the SCD pick 2 by the co-operating grooves 8 and 12, and (b) surface-bonded to the pick body 13 by means of braze 15.
[0093] FIG. 4a shows an annular bearing 18 which contains six longitudinally extending grooves 20 on its curved outer surface. The diameter of the annular ring 18 is approximately 60 mm. The grooves 20 are approximately 0.5 mm in depth. The annular bearing 18 comprises SCD material. Surrounding the SCD bearing 18 is an annular CIPed ring of steel 22, containing six grooves 24 corresponding to the grooves 20 in the SCD part 18. The CIPed steel ring 22 is approximately 0.2 mm in thickness. The CIPed steel ring 22 covers the entire outer surface (as defined) of the annular SCD bearing 18. A flange extends from the curved annular surface of CIPed steel ring, part way over the hidden end face of the SCD ring 18. The flange is not visible in FIG. 4a, but is visible and referenced 23 in FIGS. 4b and 4d which are described later. The said flange extends from the entire circumferential boundary between the curved surface of ring 18 and the said hidden end face of the ring 18 about half way towards the inner circumferential boundary defining the inner surface of the annular ring 18.
[0094] The steel ring 22 with flange 23 may conveniently be fashioned by drawing a mild steel cup over the SCD ring, so that the base of the cup is adjacent the flat end face of the SCD ring 18 that is hidden in FIG. 4a, and the sides of the cup overlap the entire curved outer surface of annular ring 18, punching a circular opening in the drawn cup, and then ClPing the cup into close contact with the ring 18 so that it follows the profile thereof.
[0095] Other variations of co-operating formations out of the surfaces of the SCD ring 18 and the steel covering 22 other than the longitudinal grooves shown are also envisaged as described hereinbefore, including but not limited to longitudinal grooves extending only part way along the length (between the flat end faces) of the SCD ring 18, angled grooves, ridges, dimples depressions, screw thread orientations and the like.
[0096] There is no specific bond between the CIPed connection member steel ring 22 and the SCD bearing ring 18, but because of the co-operating profiles of the grooved bearing ring 18 and the CIPed connection member steel ring 22, there is no relative movement between the bearing 18 and the ring 22 in a radial direction. Longitudinal movement of the bearing 18 relative to the ring 22 in the direction of the flange 23 is substantially prevented by the flange 23.
[0097] FIG. 4b is a perspective sectioned view showing half of the SCD bearing ring 18 and CIPed connection member steel ring 22 and also a second annular steel member 26 surrounding the first CIPed steel ring 22. The steel member 26 provides a mounting member, for example for mounting within a tool body. The mounting member 26 can be brazed to the CIPed ring 22 using a braze, for example a 1100 C. braze, in a conventional manner. The braze layer is indicated by reference numeral 25. The second steel member 26 surrounds the entire curved outer surface of the CIPed steel ring 22, and also has an flange 30 with one section extending away from the annular rings for further attachment within a tool body, e.g by bolting, riveting or the like, and another section 33 extending part way along the end face 32 of SCD bearing 18. The section 33 of flange 30 substantially prevents longitudinal movement of the bearing ring 18 relative to the steel coverings 22 and 26 in the direction to the right as shown in FIG. 4b. Therefore in combination the respective flanges 23 and 33 on steel covering 22 and 26 substantially prevent any relative longitudinal movement between the bearing 18 and the steel coverings. Relative rotational movement is substantially prevented by the co-operating grooves 20 and 24 in the ScD wear bearing 18 and the CIPed steel covering 22, so there is substantially no relative movement occurring between the SCD wear bearing 18 and the steel covering connection members 22 and 26.
[0098] FIG. 4c is a front sectional view through the SCD bearing 18, CIPed metal cup 22, braze layer 25, and second annular steel member 26 that are shown in perspective in FIG. 4b. FIG. 4d is a cross-sectional view through the line A-A of the FIG. 4c view. FIG. 4d shows the flange 23 on metal cup 22 and the flange section 33 of flange 33 extending from mounting member 26.
[0099] The mounting member 26 may have any suitable profile depending on its application. The embodiment shown in FIGS. 4a to 4d therefore allows a SCD bearing to be attached to any shaped metal part by means of the interlocked profiled SCD bearing shape, and co-operatingly shaped steel layer. The bearing 18 and steel layer 22 of these figures may be used in a wide variety of applications where it is desirable to combine the properties of wear resistance, as provided by the SCD material, with ease and functionality of attachment, as provided by metal parts, such as steel covering layer 22 and steel mounting member 26. For example, the bearing may be used in downhole tools. It may be used for example in roller cone drill bits. In such applications the steel member 26 may be secured into metal, alloy, carbide or cemented carbide tool bodies in a variety of ways, for example, bolted, welded, or brazed, e.g. with a braze typically in the range 600 C. to 1100 C., although higher temperature brazes could also be used.
[0100] Where there is a mounting member of the type described above, connection of the tool component to a tool body may be via the connection member and the mounting member, the connection member being secured to the tool component and bonded in some way to the mounting member, and the mounting member in turn being secured to the tool body.
[0101] FIGS. 4e and 4f show an alternative embodiment of SCD bearing 18 which can replace the bearing 18 illustrated in FIGS. 4a to 4d. In this case SCD bearing 18 is provided with upstanding projections in the form of circumferentially extending projecting sections 27 and angled projections 29. Adjacent angled projections extend at an angle to each other. The circumferentially extending projecting sections 27 may extend continuously or in isolated sections around the whole circumference of the SCD bearing 18.
[0102] FIGS. 4g and 4h show an alternative embodiment of SCD bearing 18.sup.iv which can replace the bearing 18 illustrated in FIGS. 4a to 4d. In this case SCD bearing 18.sup.iv is provided with depressions in the form of circumferentially extending grooves 27.sup.iv and angled projections 29.sup.iv. The circumferentially extending projecting sections 27.sup.iv may extend continuously or in isolated sections around the whole circumference of the SCD bearing 18.sup.iv. The FIGS. 4g and 4h embodiment is therefore the same as the FIGS. 4e and 4f embodiment except that, in the FIGS. 4g and 4h embodiment, depressions in the form of grooves replace the protrusions of the FIGS. 4 e and 4f embodiment.
[0103] FIGS. 4i and 4j show an alternative embodiment of SCD bearing 18.sup.v which can replace the bearing 18 illustrated in FIGS. 4a to 4d. It is similar to that illustrated in FIGS. 4e and 4f except that angled protrusions 29 are replaced by a plurality of longitudinal protrusions 29.sup.v each extending part way between the circumferential protrusions 27.
[0104] FIGS. 4k and 4l show an alternative embodiment of SCD bearing 18.sup.vi which can replace the bearing 18 illustrated in FIGS. 4a to 4d. It is similar to that of FIGS. 4i and 4j except that circumferential protrusions 27 and longitudinal protrusions 29.sup.v are replaced by circumferential grooves 27.sup.vi and longitudinal grooves 29.sup.vi.
[0105] FIGS. 4m and 4n show an alternative embodiment of SCD bearing 18.sup.vii which can replace the bearing 18 illustrated in FIGS. 4a to 4d. In this case SCD bearing 18.sup.vii is provided with upstanding projections in the form of longitudinally extending projecting sections 29.sup.vii and cross shaped projections 31.sup.vii. These raised projections may be arranged around the entire circumference or part only of the circumference of the SCD bearing 18.sup.vii.
[0106] FIGS. 4o and 4p show an alternative embodiment of SCD bearing 18.sup.viii which can replace the bearing 18 illustrated in FIGS. 4a to 4d. It is similar to the embodiment of FIGS. 4m and 4n except that grooved depressions 29.sup.viii and 31.sup.viii replace the raised projecting sections 29.sup.vii and 31.sup.vii.
[0107] FIGS. 4q and 4r are plan and side views respectively showing an alternative embodiment of SCD bearing 18.sup.ix, which can replace the bearing 18 illustrated in FIGS. 4a to 4d. It includes one circumferential groove 27.sup.ix, and axially extending grooves 29.sup.ix
[0108] The alternative embodiments illustrated in FIGS. 4e to 4r have two or more formations extending in different directions, and advantageously can substantially prevent relative movement between the SCD part 18 and the connection member 22 without the need for any additional flange(s).
[0109] The embodiment shown in FIGS. 4a to 4d or any of its variants as described with reference to FIGS. 4e to 4p may be used for example as a rotating bearing or a mechanical seal.
[0110] FIG. 5a shows an inside-out version of the embodiment of FIGS. 4a to 4d. FIG. 5b shows the bearing of FIG. 5a in front sectional view, with an optional inner second annular steel member 26 shown for the right-side option of the Figure. FIG. 5c is a cross sectional view through the left-side option of FIG. 5b, without the additional second annular steel member 26, and FIG. 5d is a cross sectional view through the right-side option of FIG. 5b, with the second annular steel member 26 in place. In the FIG. 5 embodiment, an annular steel ring 22 lies within the SCD ring 18, with co-operating grooves 20 in the SCD ring 18 and 24 in the steel ring 22 as before. As before a flange extends from the covering steel ring 22 across part of the end face of the SCD ring 18 (not visible in FIG. 5a but referenced as 23 in FIGS. 5c and 5d) substantially to prevent longitudinal movement of the SCD ring 18 relative to the steel ring 22 into the plane of the paper (in the orientation illustrated in FIG. 5a). Also, as before, a second steel member 26 with flange 33 across the opposed end face of ring 18 can be brazed around ring 22. This is illustrated as the right hand option in FIG. 5b. The bearing of FIG. 5b could be suitable for example as a stationary bearing.
[0111] Any of the variations illustrated in FIGS. 4e to 4p would also be suitable for use in the inside out bearing variant of FIG. 5.
[0112] Similarly any of the variations of formations of projections or depressions illustrated in FIGS. 4e to 4o for the SCD bearing would also be suitable for use in the SCD pick of FIGS. 1 to 3.
[0113] FIG. 6 is a side sectional view of two bearings similar to that illustrated in FIG. 4, but with grooves 20.sup.6 and 24.sup.6 extending circumferentially rather than longitudinally of the SCD bearing 18.sup.6 and steel cup 22.sup.6 respectively. One of the bearings is of relatively large diameter, and the other is of a relatively smaller diameter. These might be used for example as rotating bearings in a roller cone drill bit, the larger bearing operating against the main journal surface of the metal bearing pin of the drill bit, and the smaller bearing operating against the substantially parallel nose surface of the metal bearing pin of the drill bit. For each bearing the steel layer 22.sup.6 acts as a connection member, being mechanically secured to the SCD wear part 18.sup.6 by its co-operatingly shaped grooves, and bonded to mounting member 26.sup.6 by braze layer 25.sup.6. Longitudinal movement of the SCD bearing ring 18.sup.6 relative to the steel cup 22.sup.6 is substantially prevented in each case not only by the flange 23.sup.6 on the steel cups 22.sup.6 and by flanges 33.sup.6 on opposite ends of the second annular steel members 26.sup.6, but also by the mating circumferential grooves 20.sup.6 and 24.sup.6 in the SCD bearing 18.sup.6 and steel cup 22.sup.6 respectively. The flanges 23.sup.6 and 33.sup.6 are in this case optional.
[0114] FIG. 7 is a side sectional view through two bearings similar to that illustrated in FIGS. 5a to 5d, but with grooves 20.sup.7 and 24.sup.7 extending circumferentially rather than longitudinally of the SCD bearing 18.sup.7 and steel cup 22.sup.7 respectively. One is of relatively large diameter and the other of relatively small diameter. These might be used as stationary bearings, for example in a roller cone drill bit. For each bearing the steel layer 22 acts as a connection member, being mechanically secured to the wear SCD layer 18 by co-operatingly shaped grooves in the two layers, and bonded to metal shafts 26 by braze layer 25. Longitudinal movement of the SCD bearing ring 18 relative to the steel cup 22 is substantially prevented in each case in one direction by the flanges 23 on the steel cups 22. Movement in the other longitudinal direction is substantially prevented in the case of the smaller bearing by the abutting end face of the metal shaft 26 within the larger bearing, and in the case of the larger bearing by a flange 33.
[0115] The embodiments of FIGS. 6 and 7 may be used in conjunction with each other. For example the FIG. 7 embodiment may form a stationary inner bearing pair within the FIG. 6 outer rotating bearing pair.
[0116] FIG. 8a is an end view of a plurality of SCD wear parts in a thrust bearing, the wear parts being mounted in a ring around a metal housing part. FIG. 8b is a sectional view taken along line B-B of FIG. 8a and FIG. 8c is an enlarged sectional view of the circled portion of FIG. 8b. Each SCD wear part 152 is surrounded by a metal cup 158 which is brazed in turn by braze layer 160 to metal housing 120. The SCD cylinder 152 and the surrounding metal cup 158 are secured relative to each other by means of co-operating annular grooves 122 around the curved sides and by co-operating radial grooves 124 on the end face of the cylinder 152 and the base of the cup 158 (see FIG. 8c). Exposed end face 161 of the SCD solid cylindrical bearing 152 provides a thrust bearing surface. Such a thrust bearing might be suitable for example as a thrust bearing for down-the-hole drives, hydraulic motors and/or turbines.
[0117] FIG. 9 is a cross-sectional view through a nozzle 60 for passage of fluid, for example for oil/sand separation. The direction of fluid flow in use is indicated by arrow A. The nozzle contains a central bore, and is a two-part piece which comprises an inner SCD wear core part 64 and an adjacent polymeric housing part 66. The outer surface of SCD wear core part 64 is frustoconical in shape, and the part 67 may be considered to be a solid frustocone with a cylindrical bore extending through it for fluid passage. The inner surface of the surrounding adjacent housing part 66 is shaped to correspond to the SCD wear core 64. The housing part 66 is made from a readily machinable material such as a metal or alloy such as steel or from tungsten carbide. The SCD core part 64 is not only formed to be substantially frustoconical in shape but also has annular grooves 65 formed around the frustoconical part. A steel cup 67 is drawn over the frustoconical SCD part 64 and then CIPed so that it follows the profile of the core 64 into the grooves 65 of the SCD core 64. Both inner and outer surfaces of the CIPed part 67 follow the underlying profile of the SCD part 64. The CIPed steel layer 67 can then be brazed by layer 68 to the metallic housing 66. The co-operating grooves of the SCD core 64 and the steel cup 67 act in combination with the frusto-conical shape of the nozzle substantially to prevent relative movement between the SCD core 64 and the steel layer 67. An embodiment with the grooves but without the frustoconical shaping is also envisaged.
[0118] FIG. 10 is is a cross-sectional view through a nozzle 70 for passage of fluid, for example for oil/sand separation. As In FIG. 9 the direction of fluid flow in use is indicated by arrow A. The nozzle contains a central bore, and is a two-part piece which comprises an inner SCD wear core part 74 and an adjacent housing part 76. The SCD wear core part 74 is substantially cylindrical in shape, with an annular flange 79 at the fluid inlet end. The inner surface of the surrounding adjacent housing part 76 is shaped to correspond to the SCD wear core 74. The housing part 76 is made from a readily machinable material such as a metal or alloy such as steel or from tungsten carbide. In this embodiment the SCD core part 74 is formed to be substantially cylindrical in shape with an outwardly extending annular flange 79, and has annular grooves 75 formed around the cylindrical part. A steel cup 77 is drawn over the SCD part 74 and then CIPed so that it follows the profile of the core 74 into the groove 75 of the SCD core part 74. The CIPed steel layer 77 together with its flange 79 can then be brazed by braze layer 78 to the alloy housing 76. In this case the co-operating grooves of the SCD core 74 and the steel cup 77 act in combination with the flange on the SCD core 74 substantially to prevent relative movement between the SCD core 74 and the steel layer 77.
[0119] FIGS. 11 and 12 show a mechanical seal arrangement in which two annular mating SCD rings 200 with mating wear or seal faces 201 are each held in respective annular metal tool holders 202, the two SCD ring seal surfaces 201 being urged towards each other via spring 208, or the like. The manner in which the SCD rings 200 are held in the tool holder 202 is illustrated in the enlarged view of FIG. 14 FIG. 14 shows that each SCD ring 200 contains grooves on its circumferential surface and also on its mounting face which faces the tool holder 202 onto which a steel cup layer 204 has been isostatically pressed so as to follow the profile of the SCD ring. The steel cup layer 204 is brazed to the metal, alloy or carbide tool holder 202 by a braze layer 206. O ring seals are illustrated in these figures by reference 210. The tool component of this FIG. 13/14 embodiment is similar to the bearing of earlier Figures, especially earlier FIG. 4. The wear/seal part is an annular ring and the steel cup 204 covers part of the circumferential surface of the ring 200 (in contrast it covers the entire circumferential surface of the ring in the bearing embodiment illustrated in FIG. 4). The steel cup 204 in the FIG. 13/14 embodiment also covers the entire mounting face of the SCD ring 200 (the end face 209 facing the tool holder). Where we say in this specification that one layer covers another surface we mean it covers that layer at least in part, e.g. up to 10%, up to 20%, up to 50%, up to 70% or the whole of that layer.
[0120] FIGS. 13a to 13c show sequential steps in making a tool component in segmented parts. FIG. 13a shows a tool component comprising a SCD segment 220 in the form of a rectangular block. Towards the base of the block and parallel to the horizontal edges of the block, as illustrated a longitudinal groove 222 has been green machined (i.e. machined into the block when in its green state) into the block around the entire periphery of the block 220. In FIG. 13b a copper cup shaped part 224 has been CIPed into place around the block 220. The same process is then applied to a separate SCD block 220 with a separate copper cup 222, and then the two parts can be positioned adjacent each other with the cup bases facing each other and brazed together via a braze layer positioned as indicated by arrow 224 in FIG. 13c between the two facing cup faces of cups 222 and 222. Thus a larger segmented tool component is made from two smaller segments. This process can be repeated to make tool components with three or more, even a plurality of parts. Although exemplified by a rectangular block the person skilled in the art would appreciate that this technique to make segmented tool components can be applied to a wide variety of shaped tool components, and the simple block configuration is illustrated merely by way of explanation.
[0121] FIGS. 14a and 14b show other embodiments of segmented part in each of these cases a segmented nozzle.
[0122] FIG. 14a shows a nozzle is nozzle made up of two longitudinal SCD segments 320 and 322 positioned end to end so they about at join surface 324. In this one segment 320 has an end region of one diameter, this end region then tapering in a frusto conical shape from that first end region towards the other segment 322. The other segment 322 has a shape that co-operates and fits with the upper segment 320. Thus in the orientation shown there is a part horizontal and part tapered join surface between the two segments 320 and 322. Two cup shaped steel or iron connection member 334 and 336 with an aperture through the base of the cup to receive part of the nozzle walls and to surround the respective nozzle segments 320 and 322 and is CIPed in place around the nozzle part. Part of the cup base of the connection member 334 and 336 extends along the horizontal part of the join surface of the segment parts. Additionally grooves 337 and 339 are machined into end faces of nozzle segments 320 and 322 respectively, into which grooves the connection members 334 and 336 are pressed. These grooves enhance the mechanical connection. The segments 320 and 322 are brazed via their connection members by braze layer 33. An additional strip 340 may be positioned around the join area.
[0123] FIG. 14c shows another embodiment of segmented nozzle made up of two longitudinally arranged SCD nozzle segments 320 and 322. In this case the upper segment 320 in the orientation shown has a neck portion 342 extending at its lower end into a mating opening on the upper face of the lower segment 322. In this case the connection member 334 on the upper segment 320 comprises a cylindrical steel or iron part with an outwardly extending flange from one end, and the connection member 336 on the other lower segment 322 is similarly shaped part but of larger internal diameter, each connection member being CIPed onto its respective SCD nozzle part 330 and 332. A braze layer 338 joins the SCD nozzle segments via the connection members.
[0124] FIG. 14b is another segmented nozzle, but differs from FIG. 14a since in this case the segments are split along the length of the nozzle and are arranged side by side. In the orientation shown upper segment 350 and lower segment 352 of SCD provide nozzle segments that extend along the length of the nozzle and are side by side around the nozzle opening. The nozzle parts 350 and 352 thus provide a flat join surface with a cylindrical nozzle opening through and parallel to that flat surface. Grooves 356 are machined into each of the flat surfaces of nozzle parts 350 and 352 and a connection member layer 358 is pressed (CIPed) against each flat surface and into the grooves 356. A braze layer 358 then joins the connection members to each other. An outer ring or sheet holding the nozzle parts together around the outside periphery of parts 350 and 352 (not illustrated) may also be included for further securement.
[0125] FIG. 15 shows a SCD cutting tool 450 in the form of a cutting drill bit around the flat faces of which a mild steel connection member 452 has been CIPed into place. This mild steel part can then be readily attached, for example keyed into a drill shank.
