GB2182105A

GB2182105A - Composite sliding and/or bearing structure

Info

Publication number: GB2182105A
Application number: GB08626533A
Authority: GB
Inventors: Yoshio Iijima
Original assignee: Daido Metal Co Ltd
Current assignee: Daido Metal Co Ltd
Priority date: 1983-10-21
Filing date: 1986-11-06
Publication date: 1987-05-07
Also published as: GB8626533D0; GB2182105B

Abstract

A composite sliding and/or bearing structure which can be applied to automotive shock absorbers or sliding portions of hydraulic apparatus or pneumatic apparatus comprises a plastically deformed member (21a) and a sliding member (22a) formed of a brittle and heat-resistant material, eg ceramics, cermet or polyimide Pref. the deformable member is a bush made of oil-impregnated ferrous sintered material, aluminum die castings, copper sintered material or sintered porous plastics material. <IMAGE>

Description

SPECIFICATION Composite sliding and/or bearing structure Thrs Invention relates to a composite sliding and/or bearing structure which can for example be applied to automotive shock absorbers or sliding portions of hydraulic apparatus orto pneumatic apparatus in other industrial fields.

In conventional hydraulic apparatus such as automotive shock absorbers, piston rings, which are loosely received in the outer peripheral grooves, tend to jolt in the outer peripheral grooves to cause noise, vibration, wear and oil leaks.

Furthermore, since guide bushes slidable in the longitudinal direction ofthe rods of automotive shock absorbers, and other parts for other industrial machines (such as floating bushes forturbines and general idlers, spherical bearings, end bushes and double bushes) are only press-fitted and/or inserted into their housings, the outside and inside diameters ofthese bushes lack uniformity and make uneven local contact with the rods in vertical or rotatory motion, thus causing much noise, vibration, wear and oil leakage, and resulting in short life which necessitates frequent renewal. On the other hand, plastics or ceramics alone are too weak or brittle to be used satisfactorily in high speed rotating or rocking members.

Accordingly, it is an object ofthis invention to alleviate such defects of the prior art as described above. It is another object ofthis invention to provide a composite sliding and/or bearing structure of high durability which in operation reduces noise and vibration, reduces oil leakage or gas leakage so as to avoid reduction of pressure, reduces wear of sliding members and makes up for the brittleness and the low impact resistance of sliding members.

According to one aspect of the present invention, a composite sliding and/or bearing structure comprising a support member and a sliding memberwhich are united one with the other by plastic deformation of at least part of at least one ofthe members. The purpose of the deformable member isfor exampleto protect the sliding member (which is generally brittle) from shock and thermal distortion.

The invention may be carried into practice in various ways and nineteen specific embodiments will now be described byway of example, with reference to the accompanying drawings, in which: FIGURE 1A is a longitudinal section viewofan automotive shock absorber incorporating a composite sliding structure of the invention; FIGURES 1 B to 9A are cross-sectional views of first to ninth embodiments of composite sliding structures in accordance with the invention; FIGURES 9B and 9C are a perspective view and a cross-sectional view, respectively, of a supercharger in which the composite sliding structure shown in Figure SA is rnounted as a floating bearing;; FIGURES 10 to 12 are cross-sectional views of tenth to twelfth embodiments of composite sliding structures in accordance with the present invention; FIGURES 13 and 14 are cross-sectional views of spherical bearings using thirteenth and fourteenth embodiments ofthis invention; FIGURES 15 and 16 are cross-sectional views of guide bushes using fifteenth and sixteenth embodiments ofthis invention; FIGURE 17 is a cross-sectional view of an end bush using a seventeenth embodiment of this invention; and FIGURES 18 and 19 are cross-sectional views of double bushes using eighteenth and nineteenth embodiments ofthis invention.

Figure 1A shows an automotive shock absorber 10 incorporating the first embodiment ofthe composite sliding structure la (shown in Figure 1 b) in accordance with this invention. The shock absorber includes an external cylinder 11, a cylinder 12, a piston 13, a rod 14 to which the piston 13 is secured, and a rod guide 15 which is fixed to the external cylinder 11 and the cylinder 12. The piston 13 includes an embodiment of the composite sliding structure in accordance with this invention.

Referring to Figure 1 B,the composite sliding structure la includes a piston member2a offerrous metal, or more particularly sintered ferrous material, which is used as a deformable member and a self-lubricating sliding member4a used as a sliding member which has a U-shaped cross section and is plastically deformed so as to surround the entire periphery 3a of the piston member 2a by coining or caulking. Inthepiston member2a isformed a rod receiving bore 8a.The self-lubricating sliding member 4a is a dry bearing ofthetype described in Japanese Patent Publication Nos: 2452/1964 and 16950/1964, and United States Patent No: 2995462 and British Patent No: 912793, and consists of a steel layer 5a of ferrous metal, and a sliding layer6a which consists of non-ferrous metal such as porous copper, porous copper alloy, porous bronze, lead (Pb) and lead oxide (Pbxoy) ora non-metal such as PTFE (polytetrafluoroethylene) and graphite. The sliding layer 6a of the self-lubricating sliding member4a has high wear resistance, fatigue properties and seizing resistance, and slidably makes contact at the sliding surface 7a with the inner surface of a cylinder such as 12.As the composite sliding structure is formed as a single unit, the dimensional accu racy thereof may be high, and as itslidably makes uniform contact with the inner surfaces of the cylinder it is free from noise and vibration caused by loose fitting such as is found in the prior art. It is also free from wear and oil leakage caused by local contact between bushes and rods.

Referring now to Figure 2, showing a second embodiment of a composite sliding structure in accordance with this invention, the composite sliding structure 1 b is the same as the composite sliding structure lain Figure 1 B exceptforthe shape of a steel layer5b.

Figure 3 shows a third embodiment of a composite sliding structure in accordance with this invention. A self-lubricating sliding member 4e of the composite sliding structure 1c is formed in an approximately circular shape, and is secured to the groove formed on the outer peripheral surface of a piston member 2c by coining, caulking, die casting, cold working orshrink fit. This composite sliding structure 1 offers the same advantage as those ofthe preceding embodiments.

Afourth embodiment of a composite sliding struc to rue in accordance with this invention is shown in Figure 4 and has a composite sliding member id which is differentfrom the composite sliding member 1c in Figure 3, in that a self-lubricating sliding member 4d is composed of a single member.

Referring to Figure 5, which shows a fifth embodi ment of a composite sliding structure ofthis invention, this composite sliding structure 1 e differs from the third embodiment in Figure 3 in that the outer peripheral surface of a self-lubricating sliding member 4e isformed convexly and the upper and lower ends project radially inward. This convex sliding member 4e does not cause undue wear due to local uneven contact even when itstrajectory is inclined in relation to the cylinder in which it slides (not shown). As to the other effects, this embodiment is materially the same as thefirstto fourth embodiments.

Referring to Figure 6 showing a sixth embodiment of a composite sliding structure in accordance with this invention, the composite sliding structure 1f is the same as the fifth embodiment in Figure 5 except that a self-sliding member4f is composed of a single member.

Referring to Figure 7, there is shown a seventh embodiment of a composite sliding structure 1 g in accordance with the invention. The composite sliding structure 1 g is the same as the fifth embodiment in Figure 5, exceptthatthe external peripheral surface is formed concavely. The concave self-lubricating sliding member4g does notsufferundueweardueto uneven local contact, even when it is inclined in relation tothe cylinder (not shown). As to the other effects, this embodiment is materially the same as the firstto sixth embodiments.

Referring to Figure 8 which shows an eighth embodimentofa composite sliding structure in accordancewiththisinvention,thecomposite sliding structure 1 h is materiallythe same asthe seventh embodiment in Figure 7 exceptthat a self-lubricating sliding member4h is composed of a single member.

A ninth embodiment of a composite sliding structurein accordance with this invention is shown in Figure 9A. The composite sliding structure 20a ofthis embodiment is applied to a floating bush which can be usedforturbines and general idlers, This composite sliding structure 20a is composed of a bush 21 a and a sliding member22a. The material ofthe bush 21 a is an oil-impregnated ferrous sintered material which is used as a deformable material, and aluminium die castings, coppersintered material orsintered materials which have a good sliding property.The material ofthe sliding member 22a is cermet, polyimide orthe likewhich is brittle and heat resistant, and the sliding member22a is secured to a groove formed on the outer peripheral surface of the bush 21 a by coining, caulking, die casting, cold working orshrinkfit. Since the bush 21 a made of material having a good sliding property is used as a deformable member, and the sliding member 22a is made of a material which is brittle and heat resistant the inner peripheral surface 23a and the outer peripheral surface 24a of the composite sliding structure 20a can be finished to a high dimensional pre-structure by, for example, burnishing.

Figures 9B and 9C show a supercharger 16 incorporating a composite sliding structure 20a, which is the ninth embodiment ofthis invention, as a floating bearing 17. Since the inner peripheral surface 23a and the outer peripheral surface 24a of the composite sliding structure 20a are heat resistant and wear resistant, smooth rotation in the operation of the superchargerl6isenabled.

Referring to Figure 10 showing a tenth embodiment of a composite sliding structure in accordance with this invention, the composite sliding structure 20b of this embodiment is different from the ninth embodiment in Figure 9A in that a sliding member 22b is secured to a groove formed on the inner peripheral surface of a bush 21b.

Referring to Figure 11, an eleventh embodimentofa composite sliding structure in accordance with this invention, designated by reference numeral 20c, is different from the ninth embodiment in Figu re 9A in that a self-lubricating sliding membersimilarto that shown by4c in thethird embodiment in Figure 3 is secured to a groove on the outer peripheral surface of a bush 21c.

Referring to Figure 12 showing a twelfth embodi mentofa composite sliding structure in accordance with this invention, the composite sliding structure 20d ofthis embodiment, is differntfrom the tenth embodiment in Figure 10 in that a sliding member 22d, which is similarto the self-lubricating sliding member 4c in the third embodiment in Figure 3 both in function and in structure, is secured to a groove on the inner peripheral surface ofthe composite sliding structure 22d. The sliding member 22d consists of a steel layer 25d and a sliding layer 26d. The sliding member 25d and the sliding layer 26d correspond to the steel layer Sc and the sliding layer 6c, respectively, in Figure 3.

This composite sliding structure 20d has materially the same effects as the composite sliding structures 20a, 20b and 20cwhich are the ninth, tenth, and eleventh embodiments ofthis invention, respectively.

Figure 13 shows a thirteenth embodiment of this invention used for a spherical bearing 20e. This spherical bearing 20e includes a spherical seat 21 e which is used as a deformable member and a self-lubricating sliding member 22e secured to the inner bore ofthe spherical seat21 by plastic deformation. The spherical seat 21 e is made of ferrous metal, non-ferrous metal (aluminium or copper) or non-metal (plastic), oil-impregnated sintered material oroil-impregnated injected material. This self-lubricating member 22e is substantiallythe same as the self-lubricating sliding member 22d in thetwelfth embodiment in Figure 12. As the self-lubricating sliding member22e and the spherical seat 21 e are united into one body, it is possible to finish the partial peripheral surface 24e and the inner surface 23e to a predetermined dimension and in operation,the slid ing membermayslidewith lowfriction on both surfaces.

Referring to Figure 14, which shows a fourteenth embodiment of a composite sliding structure, in accordance with this invention, this embodiment is used for a spherical bearing 20f. This spherical bearing 20f is the same the thirteenth embodiment in Figure 13 exceptthata self-lubricating sliding member 22f is composed of a single member.

Figure 15 shows a fifteenth embodiment of a composite sliding structure in accordance with the invention. This composite sliding structure 209 is used foraguide bush slidable in the longitudinal direction of a rodof an automotive shock absorber. This composite sliding structure 209 includes a flanged bush 219 (sFiron sintered material and a convex self-lubricating sliding member 229 coined to the inner bore ofthe bush 21 g either after or at the same time as press fitting.The inner peripheral surface 239 of the self-lubricating member 229 becomes convex bycoiningthewholepartofthecompositesliding structure 20g. This self-lubricating sliding member 22g is in the form of a coiled bush and has a composite structuresimilartotheself-lubricatingsliding member 22d of the twelfth embodiment in Figure 12. This convexform makes it possible to reduce uneven local contact of the inner surface, noise, vibration, wear and slip-off of a self-lubricating sliding member.

Figure 16 shows a sixteenth embodiment of a composite sliding structure in accordance with the invention. This composite sliding structure 20h is used for the same purpose as in the fifteenth embodiment in Figure 15. This embodiment is identical to the fifteenth embodiment in Figure 15 exceptthat a self-lubricating sliding member22h is secured to a groove formed on the inner peripheral surface of a flanged bush 21 h by coining so as to form a convex inner peripheral surface 23h.Astothe deformable material of which aflanged bush may be composed, instead of iron sintered material (ferrous metal), either aluminium die castings (non-ferrous metal) or plastic (non-metal), ora powered pressed composition incorporating both ofthem can be used.

Figure 17 shows a seventeenth embodiment ofthis invention. This embodiment is used for an end bush 20i, which includes a cup-like bush 21 offerrous sintered material as a deformable member and a composite self-lubricating sliding member 22i in the form of a coiled bush and wholly coined after pressing into the inner bore of the bush 21 i. This end bush 20i can be finished to predetermined inner and outer diameters, and therefore it can bring about the effect of low friction since it allows for an adequate tightening margin and enhanced dimensional accuracy.

Figure 18 shows an eighteenth embodiment ofthis invention. This embodiment is used for a double bush 20j, which includes a bush 21j of porous plastic sintered material and a sliding member22j of brittle and heat resistant material such as ceramic, cermet, polyimide. The bush 21j acts as a deformable member, namely elastic material which absorbs shock and thermal distortion.The sliding member 22j is secured to the inner bore lathe bush 21j by coining. This double bush 20j,the material of which is a brittle material (heat resistant material), has the merit of lightness and has excellent heat resistance, wear nesistance and shock resistance.

Figure 19 shows a nineteenth embodiment of the invention.This embodiment is used for a double bush 20k, which is different from the eighteenth embodimentin Figure 18 in that a sliding member22 is wholly secured to the outer peripheral part of sintered material 21 k bycoining atthe sametime as press fitting.

In place ofthe dry bearings mentioned above self lubricating bearings or multi-layered bearings may be used, such as those disclosed in the following specifications: Japanese Laid-Open no: 96041/1979, United States Patent No: 4,312,772, British Patent No: 2,036,194, West German Patent No: 2,857,283, Japanese Laid Open no: 28016/1983, West German Laid-Open No: 3,22,667, United States Patent Application No: 404,673/1982 and British Patent Application No: 8,223,184/1982.

Naturally deformable materials otherthan ferrous sintered material, non-ferrous metal other than copper, copper alloy, bronze, lead and oxide, and non-metals otherthan plastic, can be used.

Inthe claims the word "annular" is intended to include objects which may be otherthan cylindrical; in particularwhich may not have circular axial crosssections.

Claims

1. A composite sliding and/or bearing structure comprising a support member and a sliding member which are united one with the other by plastic deformation of at least part of at least one of the members.

2. A composite sliding and/or bearing structure comprising a deformable member and a sliding member which are united one with the other by plastic deformation of at least one of the members.

3. A composite sliding and/or bearing structure comprising a first, deformable member, and a sliding member which is plastically deformed and united with the first deformable member into a single unit.

4. A structure as claimed in claim 3 in which the first deformable member is of at least partly annular form and the sliding member is disposed around its inner surface.

5. Astructureasclaimed inclaim3 inwhichthe first deformable member is of at least partly annular form and the sliding member is disposed around its outer surface.

6. Astructure as claimed in claim 4 or claim 5 in which the said inner and outer surfaces are substantiallyflatin axial cross-section.

7. A composite sliding structure substantially as specifically described with reference to figure 1, with orwithoutfigures 2A and 2B, ortofigure3 orfigure 4.

7. Astructure as claimed in any one of claims 3 to 5 in which the surface ofthesliding member is convex in axial cross-section.

8. Astructure as claimed in any one of claims 3to 5 in which the surface ofthe sliding member is concave in axial cross-section.

9. Astructureasclaimed in anyoneofclaims3to8 in which the sliding member is a one-piece structure being of self-lubricating sliding material.

10. A structure as claimed in any one of claims 3 to 9 in which the sliding membercomprisesaself- lubricating sliding material affixed to a second deformable member.

11. A structure as claimed in claim 10 in which the second deformable mem ber is of ferrous metal.

12. Astructureasclaimed in anyoneofclaims3to 11 in which the first deformable member is of ferrous metal, aluminium, a plastics material or any combination thereof.

13. A structure as claimed in any one of claims 3 to 12 in whichthe free surface ofthe first deformable member is polished and also acts as a sliding surface.

14. Acompositesliding and/or bearing structure substantially as specifically described herein with reference to any one or combination of the accompanying drawings.

Amendments to the claims have been filed, and havethefollowing effect: Claims 1-14 above have been replaced by new claims 1-7.

1. A composite sliding structure comprising a plastically deformed deformable member and a sliding memberwhich is provided on an outerorinner peripheral surface of the deformable member and is formed of a brittle and heat resistant material.

2. A composite sliding structure as claimed in claim 1,in which the deformable member is a bush made of a material having good sliding characteristics such as oil-impregnated ferrous sintered material, aluminum die castings, copper sintered material or sintered porous plastics material.

3. A composite sliding structure as claimed in claim 1 or 2 in which the brittle and heat resistant material is ceramics, cermet or polyimide.

4. A composite sliding structure as claimed in any one of the preceding claims in which the sliding member is at least partially contained within a groove in the outer peripheral surface of the deformable member.

5. Acompositesliding structure as claimed in claim 4 in which the sliding member is secured to the deformable member by coining, caulking, cold working orshrinkfit.

6. A composite sliding structure as claimed in any one of claims 1 to3in which the sliding member is secured to the deformable member by coining.