Bearing and connecting rod

Abstract

A bearing may include a substrate and a metallic layer disposed in contact with the substrate. An adhesive layer may be disposed in contact with the metallic layer. A supporting layer may be disposed in contact with the adhesive layer. According to an example, a polymer layer may be disposed in contact with the adhesive layer. According to another example, a polymer layer may be disposed in contact with the supporting layer.

Claims

1. A bearing, comprising: a substrate; a metallic layer in contact, on one side, with said substrate; an adhesive layer in contact, on one side, with said metallic layer; a supporting layer in contact, on one side, with said adhesive layer; a polymer layer in contact, on one side, with said adhesive layer; and wherein the adhesive layer is at least one of a deposition of adhesive between the metallic layer and the supporting layer and a strip of adhesive layer between the metallic layer and the supporting layer.

2. The bearing according to claim 1, wherein said substrate is composed of a low-carbon steel or a medium-carbon steel.

3. The bearing according to claim 1, wherein said metallic layer is composed of an aluminium alloy.

4. The bearing according to claim 3, wherein said aluminium alloy comprises from 8 to 12 wt % of Sn, from 1 to 3 wt % of Cu, from 3 to 5 wt % of Si, up to 0.7 wt % of Fe, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, and a balance of at least one of Al, impurities, and other elements.

5. The bearing according to claim 3, wherein said aluminium alloy comprises from 17 to 23 wt % of Sn, from 0.5 to 2 wt % of Cu, up to 0.7 wt % of Si, up to 0.3 wt % of Mn, up to 0.7 wt % of Fe, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, and a balance of at least one of Al, impurities, and other elements.

6. The bearing according to claim 3, wherein said aluminium alloy comprises from 5 to 8 wt % of Sn, from 0.5 to 2 wt % of Cu, from 1 to 4 wt % of Si, up to 0.3 wt % of Mn, up to 0.7 wt % of Fe, from 0.1 to 0.3 wt % of V, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, and a balance of at least one of Al, impurities, and other elements.

7. The bearing according to claim 1, wherein said metallic layer is composed of a copper alloy.

8. The bearing according to claim 7, wherein said copper alloy comprises from 6.5 to 9.5 wt % of Sn, from 0.5 to 2 wt % of Ni, up to 5 wt % of Bi, up to 0.7 wt % of Fe, up to 0.5 wt % of P, up to 0.3 wt % of Zn, up to 0.1 wt % of Pb, with a balance of at least one of Cu, impurities, and other elements.

9. The bearing according to claim 7, wherein said copper alloy comprises from 3 to 5 wt % of Sn, up to 1 wt % of Ni, up to 5 wt % of Bi, up to 0.7 wt % of Fe, up to 0.5 wt % of P, up to 0.3 wt % of Zn, up to 0.1 wt % of Pb, with a balance of at least one of Cu, impurities, and other elements.

10. The bearing according to claim 1, wherein said adhesive layer is composed of an acrylic adhesive.

11. The bearing according to claim 1, wherein said adhesive layer is composed of at least one of a silicone-based adhesive and an elastomer adhesive.

12. The bearing according to claim 1, wherein said supporting layer is composed of Al.

13. The bearing according to claim 1, wherein said supporting layer is composed of an aluminium alloy that comprises up to 3 wt % of Cu, up to 2 wt % of Mn, and a balance of at least one of Al, impurities, and other elements.

14. The bearing according to claim 1, wherein said supporting layer is composed of a polymer.

15. The bearing according to claim 1, wherein said supporting layer is composed of a polymer composition including at least 90% of at least one of polytetrafluorethylene (PTFE), polyurethane (PU), and polyester.

16. The bearing according to claim 1, wherein said polymer layer is composed of a polymer including a metal filler.

17. The bearing according to claim 1, wherein said polymer layer is a polymer composition including a metal filler, and wherein the polymer composition further includes from 6 to 8 wt % of PTFE, from 2 to 4 wt % of a silane, up to 12 wt % of a pigment, from 18 to 22 wt % of Al, and a balance of at least one of polyamide-imide (PAI), impurities, and other elements.

18. A connecting rod, comprising: a first end for mounting a gudgeon pin, a second end for mounting on a crankshaft, and a bearing disposed on at least one of the first end and the second end, wherein the bearing includes: a substrate; a metallic layer overlaying and in contact with the substrate; an adhesive layer overlaying and in contact with the metallic layer; a supporting layer overlaying and in contact with the adhesive layer; a polymer layer overlaying and in contact with the supporting layer; and wherein the adhesive layer is at least one of a deposition of adhesive between the metallic layer and the supporting layer and a strip of adhesive layer between the metallic layer and the supporting layer.

19. A bearing, comprising: a substrate; a metallic layer overlaying and in contact with the substrate, wherein the metallic layer has a composition including at least one of an aluminium alloy and a copper alloy; an adhesive layer overlaying and in contact with the metallic layer; a supporting layer overlaying and in contact with the adhesive layer; a polymer layer overlaying and in contact with the supporting layer, wherein the polymer layer is composed of a polymer including a metal filler; and wherein the adhesive layer is at least one of a deposition of adhesive between the metallic layer and the supporting layer and a strip of adhesive layer between the metallic layer and the supporting layer.

20. The bearing according to claim 19, wherein the supporting layer is composed of at least one of a metal and a polymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The aims, advantages, effects, technical and functional improvements of the present invention will be better understood from reading the description of a particular embodiment thereof, presented below, referring to the appended FIGURE. This FIGURE is schematic, and its dimensions and proportions may not correspond to reality, since it only aims to describe the invention as an example and does not impose any limitations beyond those defined by the claims given below, where FIG. 1 represents a partial cross-section of a bearing according to the present invention.

DETAILED DESCRIPTION

(2) The invention is now described in relation to particular embodiments thereof, also referring to the appended FIGURE. Specific embodiments are described in detail and are shown in the FIGURE, on the understanding that they are to be regarded as an illustration of its principles, and there is no intention to limit the invention to what is only illustrated and described in the present specification. It must be recognized that the various teachings of the embodiments discussed below may be employed separately or in any combination suitable for producing the same technical effects.

(3) According to the present specification, the term high performance, when associated with internal-combustion engines, must be understood as an internal-combustion engine that generates a specific power greater than or equal to 80 HP/L and/or operates at maximum revolutions greater than or equal to 6000 rpm for petrol engines and 4500 rpm for diesel engines, and/or operates at an operating temperature greater than or equal to 90 C. Equally, this high-performance internal-combustion engine may be combined with an automatic system for stopping and restarting, usually known as Start/Stop.

(4) Still according to the present specification, all the percentages stated herein refer to percentages by weight, unless defined otherwise.

(5) The bearing of the present invention is intended in particular to be used for internal-combustion engines, but it may be employed in any application that requires a bearing that combines the qualities of high wear resistance and being able to withstand pressure from heavy loading. More particularly, the bearing of the invention may be used in a connecting rod of an internal-combustion engine, according to the particular embodiment described here, but it also allows varied applications in other components of an internal-combustion engine, such as in crankshaft bearings, camshaft bearings etc.

(6) FIG. 1 illustrates schematically an embodiment of a bearing of an internal-combustion engine in a schematic partial cross-section. As mentioned above, internal-combustion engines are increasingly being subjected to harsher operating conditions and the bearings, particularly the bearings mounted in a connecting rod, are required to withstand higher loads, higher rotary speeds, higher temperatures and conditions of reduced lubrication.

(7) According to one embodiment of the invention, the bearing comprises a substrate (10). In particular, the substrate may be made of metallic material, such as a low-carbon or medium-carbon steel.

(8) Associated with the substrate, a metallic layer (20) is provided, which, on one side, is in contact with said substrate and, on the other side, is in contact with an adhesive layer (30), as will be seen in greater detail later on. The metallic layer has the purpose of tolerating the pressures exerted on the bearing and preventing its collapse, if the upper supporting and polymer layers wear away, besides accommodating deformations of the shaft, resisting wear, capturing contaminating particles (embeddability), supporting hydrodynamic pressures, and supplying emergency lubrication in extreme cases of operation.

(9) The metallic layer must follow the format of the substrate and, according to a first embodiment of the invention, such a layer may be formed from an aluminium alloy that may comprise from 8 to 12 wt % of Sn, from 1 to 3 wt % of Cu, from 3 to 5 wt % of Si, up to 0.7 wt % of Fe, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, with the balance comprising Al and traces of impurities and other elements. In an alternative embodiment, the aluminium alloy of the metallic layer (20) comprises from 17 to 23 wt % of Sn, from 0.5 to 2 wt % of Cu, up to 0.7 wt % of Si, up to 0.3 wt % of Mn, up to 0.7 wt % of Fe, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, the balance consisting of Al and traces of impurities and other elements. According to another alternative embodiment of the invention, the metallic layer (20) is made of an aluminium alloy that comprises from 5 to 8 wt % of Sn, from 0.5 to 2 wt % of Cu, from 1 to 4 wt % of Si, up to 0.3 wt % of Mn, up to 0.7 wt % of Fe, from 0.1 to 0.3 wt % of V, up to 0.1 wt % of Ti, up to 0.1 wt % of Pb, the balance consisting of Al and traces of impurities and other elements. Alternatively, according to a second embodiment of the invention, the metallic layer (20) is formed from a copper alloy that may comprise from 6.5 to 9.5 wt % of Sn, from 0.5 to 2 wt % of Ni, up to 5 wt % of Bi, up to 0.7 wt % of Fe, up to 0.5 wt % of P, up to 0.3 wt % of Zn, up to 0.1 wt % of Pb, with the balance consisting of Cu and traces of impurities and other elements. According to an alternative embodiment, the copper alloy of the metallic layer (20) may comprise from 3 to 5 wt % of Sn, up to 1 wt % of Ni, up to 5 wt % of Bi, up to 0.7 wt % of Fe, up to 0.5 wt % of P, up to 0.3 wt % of Zn, up to 0.1 wt % of Pb, with the balance consisting of Cu and traces of impurities and other elements. The metallic layer may be combined with the substrate by known means, such as hot roll bonding, cold roll bonding, sintering or casting, and its thickness may vary, typically, between 5 and 60 microns (10-6 m), in particular between 10 and 50 microns. Naturally, different thicknesses may be employed, depending on the application of the bearing.

(10) Associated with the metallic layer, an adhesive layer (30) is envisaged, for providing bonding between the metallic layer and the supporting layer. The adhesive layer may be formed from any adhesive suitable for forming a bond between the metallic layer and the supporting layer, as will be explained in greater detail later on. Adhesives that may be used in this layer include acrylic-based adhesives, or synthetic elastic adhesives or silicone-based adhesives. The adhesive layer may be applied by deposition of the adhesive or with a strip of adhesive layer, which may optionally be rolled together with the supporting layer (40). The adhesive layer has a reduced thickness, sufficient to maintain the necessary adherence between the metallic layer and the supporting layer.

(11) Associated with the adhesive layer, the supporting layer is envisaged (40), which has the purpose of providing greater resistance to the pressure of the polymer layer (50). In this sense, the supporting layer may be made of pure metallic material, such as aluminium, or alternatively the supporting layer may be made of a metal alloy, such as an aluminium alloy, which may comprise up to 3 wt % of Cu, up to 2 wt % of Mn, the balance consisting of Al and traces of impurities and other elements. In an alternative embodiment, the supporting layer may be made of a polymer material or of a polymer composition, such as a composition that consists predominantly, i.e. at least 90%, of PTFE (polytetrafluorethylene), or PU (polyurethane), or polyester.

(12) Above the supporting layer, and intended to come into contact with a rotating element, such as a shaft, there is the polymer layer (50). The polymer layer may be deposited and cured on the supporting layer (40), or optionally may also be envisaged as a strip that is arranged directly on the supporting layer. The polymer layer may be made of any polymer suitable for promoting a low level of friction between the rotating component and the bearing, so that the rotating component may operate with less wear, even as far as conditions of low lubrication, such as is the case, for example, of internal-combustion engines that comprise an automatic system for stopping and restarting. In particular, the polymer layer may be a polymer composition comprising 6 to 8 wt % of PTFE (polytetrafluorethylene), from 2 to 4 wt % of a silane, up to 12 wt % of a pigment, from 18 to 22 wt % of Al, the balance consisting of PAI (polyamide-imide) and traces of impurities and other elements. The thickness of the polymer layer may be between 3 and 25 microns, and more particularly between 6 and 15 microns. Naturally, this thickness may vary, depending on the application for which the bearing is intended.

(13) The invention also relates to a connecting rod for an internal-combustion engine, the connecting rod comprising a small end on which a gudgeon pin is mounted, and a big end for mounting on a crankshaft, wherein said connecting rod comprises a bearing as defined above.

(14) Although the invention has been described with respect to particular embodiments thereof, a person skilled in the art will be able to make changes or combinations not contemplated above, but without deviating from the teachings described here, besides expanding to other applications not considered in the present specification. Therefore, the accompanying claims must be interpreted as covering all and every equivalents that fall within the principles of the invention.