GB2170289A

GB2170289A - Master cylinder tube attachment

Info

Publication number: GB2170289A
Application number: GB08600264A
Authority: GB
Inventors: William John Peter Constance
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1985-01-17
Filing date: 1986-01-07
Publication date: 1986-07-30
Also published as: GB8501137D0; GB2170289B; ES550917A0; EP0189244A2; US4676427A; BR8600166A; JPS61206891A; JPH0353482B2; IN166569B; ES8702204A1; DE3660953D1; EP0189244A3; EP0189244B1; GB8600264D0

Description

GB2170289A 1 SPECIFICATION components. Typically, the body and spacer

elements may be secured together as a sub Master cylinder flange attachment assembly prior to being placed around the tube.

This invention relates to a method of making 70 Alternatively, the body and spacer elements an assembly including a metal tube and a sur- may be integrally formed, conveniently by rounding body, and also to such an assembly pressing or rolling, prior to being placed on produced by application of the method and the tube. It can then be advantageous to bond useful, for example, as the pressure cylinder this integral component to the tube with the of a vehicle hydraulic system master cylinder 75 spacer in engagement with the abutment.

for brake or clutch actuation, the surrounding Typically, the spacer element is a generally body then being in the form of an outwardly cylindrical sleeve having an internal diameter projecting flange serving for the mounting of slightly greater than the external tube dia the assembly on a vehicle. meter, said sleeve being formed at one end One conventional manner of securing a sur- 80 thereof with a generally radial projection, pre rounding flange to a pressure cylinder is to ferably in the form of a continuous peripheral provide the flange with an aperture of slightly radial flange, for engagement by the surround smaller diameter than the cylinder external di- ing body.

mension at the intended flange location, and Conveniently, the tube may be initially open pressing the flange onto the tube at said loca- 85 at both ends and the method then includes tion. Such a pressing operation can engender the step of permanently closing one of the a large radially inward force on the cylinder tube ends, by securing therein an end closure wall, which sometimes results in unacceptable element, preferably by welding. In one practi distortion of the cylinder bore and conse- cal form of the method, the end of the tube quently in additional machining to correct the 90 to be closed is formed with an internal shoul distortion, or scrapping of the assembly. A der and the closure element, usually in the further disadvantage of the aforesaid conven- form of a disc-like plug is brought into abut tional procedure is that, in order for the flange ment with the shoulder, an end portion of the to have sufficient internal surface area around tube being deformed inwardly against the ad its bore to be afforded stable support on the 95 jacent face of said element and the element cylinder, and also for it to be sufficiently sub- being then secured by welding to said in stantial to withstand the pressing operation, it wardly deformed portion. This arrangement is has been necessary for the flange to be of thought to be particularly effective for with substantial thickness, which increases the standing high internal cylinder pressures, such weight of the assembly undesirably and repreas occur, for example, in a brake or clutch sents additional cost. master cylinder.

It has been proposed to weld the flange in The invention will now be described, by position in order to reduce the risk of the way of example, with reference to the accom flange and tube becoming separated in use, panying drawings in which:

but the application of welding heat to the tube 105 Figure 1 illustrates one form of assembly is a further factor which may give rise to tube made by the method of the invention, being a distortion. pressure cylinder for use in an hydraulic sys An object of the present invention is to pro- tem; vide an improved method of making an as- Figure 2 illustrates one stage in the method sembly including a metal tube and a surround- 110 of the invention for producing the pressure ing body, such as a flange, which alleviates or cylinder of Figure 1; avoids the problems above referred to. Figure 3 is a view similar to Figure 2 illus According to the invention, a method of trating another stage in the method of the making an assembly including a metal tube invention; and a surrounding body comprises providing 115 Figure 4 is an enlarged side view of one an abutment at a desired location on the tube, component of the assembly; placing said body in surrounding relationship Figures 5 to 7 are details in section of parts to the tube and moving it along the tube to a respectively of alternative embodiments of the position in which it is spaced from said abut- assembly of the invention, the latter being in ment by an interposed spacer element engag- 120 an intermediate stage of manufacture, and ing said abutment, and effecting a securing Figure 8 is a cross-sectional view showing a operation between at least the spacer element further alternative embodiment of the as and tube. sembly made by the method of the invention.

Preferably, said tube abutment is formed by Referring to Figure 1, this illustrates a pres- flaring an open end of the tube. The securing 125 sure cylinder, primarily for use in a vehicle operation may conveniently be effected by hydraulic clutch or brake actuating system, welding or bonding. and including a cylinder 1 and a radially ex The body and spacer elements may be se- tending mounting flange 2 having holes 2A for parate components, in which case said secur- the reception of fixing bolts or the like. The ing operation is also effected between these 130 invention is concerned particularly with the at- 2 GB2170289A 2 tachment of the flange 2 to the cylinder 1. ing of the components together and this is The cylinder 1 is preferably in the form of a now effected by applying an axial force such drawn tube of uniform cross-section, open at as to urge the sleeve 5 and mounting flange 2 both ends. One end of the tube is closed by towards the flange 4 and applying an appro means of a plug 3 which would normally be 70 priate electric current such that the projections inserted and secured as a final step in the 10 and 11 fuse and welding is effected be method, as will be described hereinafter. The tween the sleeve and the flange 4 at one end open end portion of the tube 1 is flared out- and mounting flange 2 at the other end. It will wardly to provide a flange 4 acting as an be seen that the welding locations are spaced abutment against which a sleeve 5 is brought 75 from the tube 1 with the advantage that no into engagement, the sleeve 5 itself having a significant welding heat is applied to the tube radial flange 5A against which the flange 2 is 1 and deformation of the internal bore of the brought into engagement and secured. A pro- tube is minimised ' tective boot 6 has a bead 7 which is located The insertion of the plug 3 to seal the end behind the flange 4 and trapped between the 80 of the tube remote from the mounting flange outer surface of the sleeve 5 and a retaining is typically deferred until the flange welding clip 8. The clip 8 is provided with a series of operation has been completed, so that there crimps 9 around its internal periphery and has is an unobstructed view along the bore which a certain resilience such that it can be de- facilitates inspection of the latter to detect any formed to enable the crimps 9 to pass over 85 untoward scoring or other deformation of the the outer edge of the flange 4 and, by resili- internal wall. Once the inspection has been ent recovery of the device, become located completed, the plug, which is dimensioned to behind the flange 4, as shown. In this manner, have an interference fit within the tube, is in the retainer 8 is fixed axially relative to the serted and secured in place and sealed around cylinder 1 and can advantageously serve as a 90 its periphery by welding, as represented at 3A piston stop and push rod retention device, in Figure 2. The preferred welding method for thereby eliminating the use of conventional cir- this purpose is Tungsten Inert Gas (T.I.G.) clips and consequent machining of annular welding, although other methods are not pre grooves for the reception thereof. cluded.

Figure 4 illustrates the sleeve 5 in more de- 95 Figures 5 and 6 illustrate alternative ways of tail and it will be seen that it initially is pro- securing the end plug 3 within the end of the vided with a number of pressed-out projec- cylinder 1. In Figure 5, an end portion 313 of tions 10 from the end surface of the plain end the bore is opened out to create an internal of the tube, and also with further projections shoulder 3C, against which the plug 3 is 11 pressed into the flange 5A so as to pro-. 100 urged when inserted, again as an interference ject axially beyond the normally axially out- fit, within the opened out bore portion. The ward extent of the flange. These projections end portion 313 is then manipulated so as to 10, 11 are for use in a subsequent projection roll it over inwardly against the outer face of welding operation, as will be described. the plug 3, in order to provide a secure abut The method of the invention is typically car- 105 ment against pressure urging the plug axially ried out by first manipulating one end of the outwardly. The plug is then finally secured in tube 1 so as to flare it outwardly and thereby position and sealed by T.I. G. or other suitable produce the flange 4. Once this has been welding at 3D.

done, the sleeve 5 is introduced onto the In the preferable alternative illustrated in Fig outer surface of the tube 1 in surrounding re- 110 ure 6, a similar opening out of a bore portion lationship and moved along the tube towards 313 is effected, again to create a shoulder 3C, the flange 4. The sleeve 5 is arranged so that the essential difference being that the end its own flange 5A faces in the opposite direc- portion 313 is manipulated so as to roll a por tion to the flange 4. The mounting flange 2 is tion 3E thereof back on itself to provide the then also placed around the tube 1 and 115 necessary abutment surface after interference moved therealong towards the flange 5. Figure fitting of the plug 3. T.I. G. or other suitable 2 illustrates an intermediate stage of the welding is then effected between the rolled method in which the sleeve 5 and flange 2 back portion 3E and the plug 3 to secure and are located on the tube 1 but still displaced seal the plug. It is found that the arrangement from their final positions for illustrative pur- 120 of Figures 5 and 6, and particularly that of poses. Figure 6, provides an effective resistance The next stage in the procedure is illus- against the very high pressures prevailing trated in Figure 3 in which the sleeve 5 is within the cylinder 1 when the cylinder is used moved so as to bring the projections 10 into as a master cylinder in a vehicle hydraulic engagement with the tube flange 4, and the 125 clutch or braking hydraulic system.

mounting flange 2, shown alternatively in this As will be seen from Figure 7, a further drawing as a flat plate, is moved into engage- alternative plug fixing can be effected by sim ment with the projections 11 on the flange ply manipulating the end portion 313 to roll it 5A. The projections 10 and 11 are provided over inwardly so as to provide an abutment for the purpose of permitting projection weld- 130 for the plug 3, this time inserted from the 3 GB2170289A 3 open end of the tube 1. The plug is provided by bonding or welding.

with pressed out welding projections 3F which 4. A method according to any one of the are placed against the abutment, as shown, preceding claims wherein the spacer element welding being effected by the passage of is a generally cylindrical sleeve having an inter electric current to fuse the projections. 70 nal diameter slightly greater than the external In the embodiment illustrated in Figure 8, tube diameter.

Claims

the flange
2 and sleeve 5 are formed inte- 5. A method according to Claim

4 wherein grally, as by rolling or pressing for example, the sleeve is provided at one end thereof with and the tube 1 is formed as a single deep a generally radial projection for engagement by drawn component with one open end sur- 75 the surrounding body.

rounded by the flange 4. The method of form- 6. A method according to Claim 5 wherein ing the tube and flange assembly in this case said projection is in the form of a continuous is to provide a layer 20 of adhesive or other peripheral radial flange.

suitable bonding material either on the outer 7. A method according to any one of the surface of the tube or on the internal surface 80 preceding claims wherein the body and spacer of the sleeve 5, and place the components in element are separate components and said se the positions illustrated with the free end of curing operation is also effected between the sleeve abutting the flange 4 in order to these components.

set the final position of the flange 2 on the 8. A method according to any one of tube. It would alternatively be possible to em- 85 Claims 1 to 4 wherein the body and spacer ploy a welding technique for securing the flan- elements are integrally formed and said secur ge/sleeve assembly and the tube could be a ing operation is effected between the spacer fabricated assembly, as in the previously de- element and the tube.

scribed embodiments. 9. A method according to Claim 8 wherein It will be appreciated that the use of the 90 the securing operation is effected by bonding method of the invention enables a mounting between the inner and outer cylindrical sur flange to be securely attached to a tube 1 by faces respectively of the spacer element and welding, without the necessity for welding to tube.

any part of the tube which, in use, is swept 10. A method according to any one of the internally by the piston, thereby avoiding de- 95 preceding claims wherein the tube is initially formation of the cylinder bore by the heat of open at both ends, the method including the welding, and also makes possible the use of a step of permanently closing one of the tube relatively lighvweight mounting flange. More- ends by securing therein an end closure ele over, the use of the sleeve 5 and abutment 4 ment.

on the tube sets the position of the flange 2 100 11. A method according to Claim 10 on the tube in a simple and effective manner wherein the end of the tube to be closed is and thereby greatly facilitates manufacture and formed with an internal shoulder and the clo assembly of the components. The invention sure element is brought into abutment with also provides various effective ways of sealing the shoulder, an end portion of the tube then an open-tube end when open ended steel 105 being deformed inwardly against the adjacent tube is employed in the method of the invenface of said element and the element being tion. secured to the inwardly deformed portion.

Although the invention has been described 12. A method according to Claim 10 in relation to pressure cylinders for vehicle hy- wherein an end portion of the tube is de draPlic systems, it may be used in the manuformed inwardly to form an abutment and the facture of other assemblies such as shock ab- closure element is passed along the tube into sorbers for example, which include a metal engagement with the abutment and secured in tube and surrounding flange or other body. position.

13. A method according to any one of CLAIMS 115 Claims 10 to 12 wherein the closure element 1. A method of making an assembly includ- is secured in position by welding.

ing a metal tube and a surrounding body com- 14. A method of making an assembly in prises providing an abutment at a desired lo- cluding a metal tube and a surrounding body cation on the tube, placing said body in sursubstantially as hereinbefore described with rounding relationship to the tube and moving 120 reference to Figures 1 to 4, or Figures 1 to 4 it along the tube to a position in which it is as modified by Figure 5, Figure 6 or Figure 7, spaced from said abutment by an interposed or with reference to Figure 8 of the accom spacer element engaging said abutment, and panying drawings.

effecting a securing operation between at least 15. An assembly including a metal tube and the spacer element and tube. 125 a surrounding body, made by the method of 2. A method according to Claim 1 wherein any one of Claims 1 to 10.

said tube abutment is formed by flaring an Printed in the United Kingdom for open end of the tube. Her Majesty's Stationery Office, Dd 8818935, 1986, 4235.
3. A method according to Claim 1 or Claim Published at The Patent office, 25 Southampton Buildings, 2 wherein said securing operation is effected London, WC2A 1AY, from which copies may be obtained.