GB2127117A

GB2127117A - Caliper-type disc brakes

Info

Publication number: GB2127117A
Application number: GB08316314A
Authority: GB
Inventors: Gruenberg Hubertus Von; Frederick Corey; Jonathan Martin Rowell
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1982-08-30
Filing date: 1983-06-15
Publication date: 1984-04-04
Also published as: GB2127117B; DE3322232A1; IT8322342A1; DE3322232C2; FR2532384A1; JPS5958239A; IT8322342A0; GB8316314D0; FR2532384B1; IT1164347B

Abstract

A composite brake caliper includes a support member (1) of cast iron which has a support portion (11) bounding a through recess or opening. At least the support portion is at least partially covered by a body (3) of a precision-mouldable material, such as aluminium. The mouldable body may have a portion extending into the through opening of the support portion and having a precision-cast internal surface (33). A mounting portion (21) of an actuating cylinder, preferably a deep-drawn steel, is introduced into the through opening and forms an interference fit with the internal surface (32) of the portion of the body which is located within the through opening. The support portion may also be circumferentially incomplete, in which case the body of mouldable material externally covers the support portion and at least the mounting portion of the cylinder, thus positionally securing the cylinder in the open recess. <IMAGE>

Description

SPECIFICATION Caliper-type disc brakes The present invention relates to caliper-type disc brakes in general, and more particularly to brake calipers of floating-caliper spot-type vehicle disc brakes.

There are already known various constructions of spot-type disc brakes using brake calipers which transmit force from one axial side of a brake disc to the other. A disc brake of this type typically includes two brake shoes each situated on a respective one of the axial sides of the brake disc. The brake shoes are mounted for movement in the axial direction toward and away from the brake disc, either on a carrier member or on the caliper, or between the carrier member and the caliper. While the brake disc is free, in the absence of braking action, to rotate about its axis at the same angular speed as the wheel associated therewith, the carrier member and thus the caliper mounted thereon are held against rotation about this axis.Thus, upon brake application, which results in movement of the brake shoes from the opposite axial directions into frictional engagement with the brake disc, the rotation of the brake disc will be retarded and eventually stopped if the brake disc is already rotating or at least hindered if not prevented altogether if the brake disc is stationary at the same time of brake application.

The movement of the brake shoes toward and away from the brake disc can be achieved in various ways, usually employing at least one hydraulically operated wheel brake-actuating cylinder-end-piston unit. In floating-caliper disc brakes, the caliper is mounted on the carrier member for movement in opposite directions substantially parallel to the axial direction of the disc. This floatingly mounted caliper is capable of transmitting at least the force which is required for bringing the brake shoe situated at the opposite side of the brake disc into braking engagement with the brake disc. To achieve the transmission of this force, the cylinder of the wheel brakeactuating cylinder-and-piston unit is rigid, and usually integral, with the caliper so that they move in unison.The cylinder slidably accommodates a piston which directly acts on the brake shoe situated at the same side of the brake disc as the cylinder-andpiston unit once the pressure inside this unit rises above the level needed to overcome frictional forces within this unit. At this time, the hydraulic medium in the actuating cylinder-and-piston unit exerts an equal but oppositely-oriented reaction force on the cylinder, this reaction force being transmitted to the brake shoe situated at the other side of the brake disc through the caliper.

The floating mounting of the caliper on the carrier member may be accomplished in different ways such as by providing axially-extending co-operating guide surfaces on the caliper and on the carrier member or by using guide pins rigidly connected to one, and guided in respective bores of the other, of the caliper and the carrier member. In any event, it is mandatory that the caliper be provided with precision surfaces, that is, with surfaces which are machined or otherwise shaped to conform to exact specifications as to dimensions, tolerances, smoothness and/or adherence to the desired course.

In the currently-manufactured constructions of floating-caliper spot-type vehicle disc brakes, the caliper is made of cast iron, which is popular for its substantial strength and relatively low cost. The caliper proper is usually formed integrally with the cylinder of the wheel brake-actuating cylinder-andpiston unit. However, experience has shown that the need for machining the various precision surfaces on the various parts of the composite caliper combining the caliper itself and the cylinder significantly increases the final cost of the composite caliper, both in terms of capital investment into the machinery capable of machining such precision surfaces, and expenditure of skilled labour.It will be appreciated that precision surfaces cannot be obtained in a die-casting operation in which the composite caliper is manufactured, due to the shrinkage and other distortion of the composite caliper following the die-casting operation.

Accordingly, it is a general object of the present invention to avoid the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide a composite brake caliper, especially for use in floating-caliper spot-type vehicle disc brakes, which does not possess the disadvantages of conventional brake calipers.

Another object of the present invention is to construct the brake caliper of the type here under consideration in such a way as to reduce the amount of required machining to a minimum orto make it possible to perform the remaining necessary machining operations in a convenient and inexpensive manner.

A further object of the invention is to devise a brake caliper which is simple in construction, inexpensicve to manufacture, reliable in operation and which will result in reduction of the final cost of the brake caliper, and in the weight thereof, without sacrificing stiffness.

According to the invention in one aspect, there is provided a caliper for a brake, especially a floatingcaliper spot-type vehicle brake, comprising a support member of a rigid first material, including a support portion bounding a recess; a separate brake-actuating cylinder of a second material, having a mounting portion received in the recess of the support member; and at least one body of a mouldable third material at least partially covering the support member.

The first, second and third materials advantageously are different metallic materials, such as iron, especially cast iron for the support member, steel for the brake actuating cylinder, and aluminium, especially cast aluminium, for the mouldable body. The mouldable body is then advantageously provided with at least one precision cast contact surface thereon. It is further advantageous if the brake actuating cylinder has at least one precision machined surface thereon.

A particular advantage of the above-discussed construction is that, by providing at least one of the required precision surfaces as a precision cast surface on the mouldable body, the number of required machining operations and the complexity of such machining operations is significantly reduced. Because of the provision of the cast body of, for instance, aluminium, and the separate cylinder of, for instance, steel, all of the precision surfaces can be located either on the body, or a plurality of such bodies, or on the separate cylinder, so that no machining operations need be performed on the support member of, for instance, die-cast steel.This considerably simplifies the manufacture of the composite caliper as compared with conventional brake calipers, especially when the machining of the remaining precision surfaces on the separate cylinder is performed prior to its assembly with the caliper proper.

An advantageous construction of the caliper component of the present invention is obtained if at least the support portion of the support member is at least externally embedded in the body. In this construction, all externally situated precision surfaces, which previously had to be machined on the cast iron caliper, can now be precision cast on the body.

However, it is also advantageous if the body has a portion covering the support portion of the support member within the recess and having a precision cast internal contact surface which is in contact with the mounting portion of the cylinder in the finished caliper component. As a consequence of this expedient, it is not necessary to machine the surface of the support portion of the support member which bounds the recess to assure proper fitting accommodation of the mounting portion of the cylinder in the recess. Rather, the precision cast internal surface of the body will provide the required fit such as an interference fit, with the mounting portion of the cylinder.

According to a further advantageous concept of the present invention, at least the mounting portion of the cylinder has a cylindrical outer periphery, and the support portion of the support member has a circumferentially complete annular configuration so that the recess is formed as a cylinderical opening through the support portion. A particular advantage of this construction, and particularly of the circumferential completeness of the support portion, is that the cylinder is safely retained in the recess against movement in any radial direction, no matter what radially-oriented forces may act thereon.Advantageously, the cylinder has at least one abutment portion atthe mounting portion, this abutment portion extending outwardly beyond the periphery of the cylinder and abutting the support portion of the support member when the mounting portion of the cylinder is fully received in the cylindrical opening of the support member.

A construction is also advantageous in which the support portion of the support member and the body constitute a composite structure, when the abutment portion abuts the composite structure as the mounting portion of the cylinder is fully received in the recess. In this manner, the cylinder is prevented by the abutment portion from moving in at least one of its axial directions in response to axially oriented forces acting thereon.

In an alternative construction, the support portion of the support member extends along a partly annular course so that the recess has a substantially radially-extending open region. In this case, at least both the mounting portion of the cylinder and the support portion of the support member are embedded in the body at and around the open region of the recess. This open construction of the recess simplifies the assembly of the cylinder with the support member; however, given the substantially greater cost of aluminium as compared with cast iron, any savings in labour expenditure may be outweighed by the increased cost of the material, so that a detailed cost analysis, taking into consideration the number of calipers to be manufactured, will have to be made before deciding whether to use the openrecess or the closed-recess construction.

The support member of the caliper component of the present invention includes at least one bridge portion extending from the support portions sub stantiaily parallel to the axial direction of the cylinder received in the recess and at a radial offset from this axis, the bridge portion having a free end axially offset from the support portion, and a brake-shoe operating portion rigid with the free end of the bridge portion and extending substantially normal to and toward the cylinder axis, then the operating portion is advantageously embedded in the aforementioned body of mouldable material, or a separate body of such mouldable material.Here again, the body of mouldable material may be provided, in the same manner as discussed before, with at least one precision cast surface, thus eliminating the need for machining any such precision surface on the operating portion. This precision cast surface may be, for instance, a surface bounding an opening in the cast body at the operating portion.

In accordance with another aspect of the present invention, there is provided a method of manufacturing a caliper for a brake, especially a floating-caliper spot-type vehicle disc brake, comprising the steps of forming a support member of a rigid metallic material with a support portion bounding a recess, introducing a mounting portion of a separate actuating cylinder of a second material into the recess, and moulding at least one body of a mouldable metallic third material at least onto the support member to cover at least partially the latter.

The moulding step advantageously includes forming at least one precision surface on the body, or forming at least one precision opening in the body.

Moreover, the method of the present invention may further comprise the step of providing at least one precision surface on the cylinder, especially by machining the precision surface on the cylinder.

It is especially advantageous if the step of providing at least one precision surface on the cylinder is performed priortothe introduction of the mounting portion of the separate brake actuating cylinder into the recess. A particular advantage of this approach is that the machining operation can be easily performed, given the simple cylindrical hollow shape of the cylinder, be it at the outer circumferential surface, at the inner circumferential surface, or at any of the end faces of the cylinder, by simply clamping the cylinder in a chuck or similar holding device and performing substantially coaxial relative movement between the cylinder and the machining tool or tools.There is no need to take any special measures with respect to the tools or the holders, especially since the cylinder is being machined separately from the caliper proper so that the latter does not place any spacial restrictions on the location, mounting or type of movement of the tools relative to the cylinder.

This approach is particularly advantageous when the moulding step is performed prior to the introducing step. Under these circumstances, there is no danger that any previously machined precision surfaces could become distorted during the moulding step due to the transfer of heat between the mouldable material and the separate cylinder through the support portion of the support member.

This approach also renders it possible to provide the body of the mouldable material at the interior of the recess as to form the contact surface which contacts, with the desired fit, the mounting portion of the cylinder upon assembly.

Embodiments of the invention will now be described by way of example with reference to the enclosed drawings, in which: Figure 1 is an axial sectional view through a composite brake caliper according to the invention, Figure 2 is a top plan view of a support member used in the composite brake caliper of Figure 1; Figure 3 is an end elevational view of the support member taken in the direction of the arrow A of Figure 2; Figure 4 is an end view of the composite caliper taken in the direction of the arrow B of Figure 1; Figure 5 is an exploded perspective view of the combination of a support member with an actuating cylinder; and Figure 6 is a view similar to Figure 1 but incorporating the combination of Figure 5 and a further modification.

Referring now to the drawing in detail, and firstly to Figure 1 thereof, it may be seen that the reference numeral 1 has been used to identify a support member of a composite brake caliper according to the present invention. The support member 1 as illustrated in Figure 1 includes an annular, circumferentially complete, support portion 11, a substantially axially-extending bridge portion 12 merging into a free end portion 13, and a substantially radially inwardly-extending brake-shoe operating portion 14.

In use, the composite brake caliper straddles a brake disc, so that the support portion 11 is situated at one axial side of the brake disc, the free end portion 13 and the brake-shoe operating portion 14 are situated at the other axial side of the brake disc, and the bridge portion 12 extends radially outwardly past the brake disc.

The support portion 11 has an internal surface 15 which circumferentially bounds a cylindrical recess or through opening in the support portion 11. A wheel brake-actuating cylinder 2 is partially accommodated in the through bore of the support portion 11. As shown in Figure 1, the support portion 11 is embedded in a body of 3 of a mouldable material.

The body 3 has an external portion 31 which externally covers the support portion 11, and an internal portion 32 which covers the internal surface 15 of the support portion 11 and has a precision moulded or cast internal surface 33. The internal portion 32 of the body 3 then supports the cylinder tube in the through opening of the support portion 11 of the support member 1. The cylinder 2 has a mounting portion 21 which is received in the through opening of the support portion 11 and has an external surface 22 that is in contact with the internal surface 33 of the internal portion 32 of the body 3.The surfaces 33 and 22 are preferably so dimensioned relative to one another as to obtain an interference fit, so that the mounting portion 21 of the cylinder 2 will be safely retained in the internal portion 32 of the body 3 once introduced thereinto, even when the composite caliper is subjected to vibrational or other forces during the transportation, assembly or use thereof. It is to be mentioned at this juncture that the internal surfaces 33 of the portion 32 of the body 3 have such characteristics, especially adherence to the desired diameter and surface smoothness, as not to require machining.It would be impossible to give such properties to the surface 15 of the support portion 11 of the support member 1, especially since the support member 1 is preferably made of cast iron so as to have the desired strength, which means that the surface 15 is, of necessity, very rough and substantially deviates from its desired diameter, substantially deviates from its desired diameter, at least locally, so that this surface 15 would have to be machined before being able to accommodate and co-operate with the mounting portion 21 of the cylinder 2.

The cylinder 2 is advantageously produced in a deep-drawing operation, which has the advantages not only that the cylinder 2 can be manufactured in a relatively inexpensive manner, but also that the outer circumferential surface thereof, including the outer surface 22 of the mounting portion 21, has the precise diameter as desired and the surface smoothness which is required for co-operation or fit with the internal surface 33 of the body 3.

The cylinder 2 bounds an internal pressure chamber which is circumferentially delimited by an internal surface 24. This internal surface 24 is machined to precision since it is in a sliding contact with an actuating piston at least partially received in the pressure cylinder 2 in the assembled condition of the disc brake. This actuating piston acts directly, in a conventional manner, on the brake shoe of the wheel brake which is arranged at the same axial side of the brake disc as the support portion 11 and the cylinder 2, when pressurised fluid is present in the internal chamber of the cylinder 2. The pressurised medium, usually hydraulic brake fluid, also acts on the bottom wall of the cylinder 2, thus exerting a reaction force thereon which is transmitted through the support member 1 to the brake shoe arranged at the opposite side of the brake disc from the cylinder 2.

An annular groove 25 is machined in the interior of the cylinder 2, preferably in the abutment portion 23.

This annular groove 25 serves to accommodate, again in a conventional manner, a sealing element which seals the interface between the internal surface 24 of the cylinder 2 and the outer circumferential surface of the actuating piston. A recess 26 having a diameter exceeding that of the surface 24 is provided at the end face 27 of the cylinder 2. This recess 26 partially accommodates, in an assembled condition, a dust boot of a conventional construction which extends between the outer peripheral surface of the actuating piston and the cylinder 2 and prevents dust and other environmental contaminents from reaching the interface between the actuating piston and the cylinder 2.The surfaces bounding the groove 26 and the end face 27 are also machined and/or bevelled so as not to present any sharp points or edges to the dust boot which is of an elastomeric material and thus could be damaged by sharp points or edges. Thus, it may be seen that the cylinder 2 has a number of surfaces which have to be machined to precision. However, since the cylinder 2 is a component which is separate from the remainder of the composite caliper and has a rotationally symmetrical shape centered on an axis on which the surfaces to be machined are centered as well, the aforementioned machining operations are easy to accomplish, so that only a minimum additional expense will be incurred by machining such surfaces. Thus, such machining operations are preferably performed prior to the assembly of the cylinder 2 with the remainder of the caliper.

The cylinder 2 is further provided, at its end face facing away from the brake-operating portion 14 in the assembled condition, with a projection 28 which is integral with or connected to the cup-shaped main portion cylinder 2. As illustrated, the projection 28 is a separate element which is connected to the cup-shaped main portion of the cylinder 2, for instance, by welding. This is particularly advantageous when the main portion of the cylinder 2 is deep-drawn as mentioned before. Athreaded through bore 29 is provided in the projection 28 and in the bottom wall of the main portion of the cylinder 2.The aforementioned pressurised medium is admitted into the internal chamber of the cylinder 2 through this threaded bore 29 after a connecting hose or a similar duct has been connected to the projection 28, preferably by threading a portion thereof into the threaded bore 29. The projection 28 is provided, in a conventional manner, with a protuberance 28a which has a flat surface at its portion facing the viewer in Figure 1, the protuberance 28a being situated at a predetermined radial distance beyond the bore 29 as seen in Figure 1 The presence of this protuberance 28a and of its flat surface, in co-operation with compatiblyconfigurated connecting fitting of the pressurised fluid hose or duct, assure that the hose or duct can only be mounted in one predetermined position on the projection 28.

The brake-operating portion 14 of the support member 1 has through opening 16 therein.

Another body 3', separate from the body 3 but also made of a precision mouldable material, has at least partially the brake-operating portion 14 embedded therein. As illustrated, the body 3' has an external portion 34 which externally covers the brakeoperating portion 14, but terminates at the free end portion 13, as well as an internal portion 35 which covers the surface bounding the through opening 16 in the brake-operating portion 14. The portion 35 is again cast to precision so that, unlike the case of the conventionally constructed brake calipers, it is no longer necessary to machine the surface of the brake-operating portion 14 which faces the respective brake shoe or the internal surface which bounds the opening 16.

Turning now to Figure 2 of the drawing, which illustrates the support member 1 priorto its partial embedding of the bodies 3 and 3', it may be seen that its connecting or bridge portion 12 includes two arms 12a and 1 2b which extend substantially parallel to one another between the support portion 11 and the free end portion 13. Each of the bridge arms 12a and 1 2b is provided, at its surface facing away from the brake disc in use, with a respective reinforcing bulge or rib 17a or 17b which extends substantially parallel to the axial direction. The support portion 11, the arms 12a and 12h, and the free end portion 13 together bound an opening into which the brake disc may partially penetrate.This renders it possible to situate the brake caliper closer to the axis of rotation of the brake disc than it could be located in the absence of such an opening.

As may be seen in Figure 3, the brake-operating portion 14 has two sections 14a and 14b which are symmetrically arranged at the diametrically opposite sides of the axis of the composite caliper. These two sections 14a and 14b are respectively provided with openings 16a and 1 6b which correspond to the opening 16 discussed above in connection with Figure 1. It may also be seen in Figure 3 that the support portion 11 of the support member 1 has an annular configuration.

As shown in Figure 4, the body 3 extends all around the support portion 11, both externally and internally, thus covering the reinforcing bulges 1 7a and 17b as well, at least at the region of the support portion 11. The body 3 further includes two mounting portions 36a and 36b which respectively bound precision-cast apertures 37a and 37b. The apertures 37a and 37b are used for mounting the composite caliper on a carrier member for movement in the axial direction. This may be accomplished, in a conventional manner, by providing the carrier member with two guiding rods extending parallel to the axial direction and passing through the apertures 37a and 37b, respectively.Since the surfaces bounding the respective apertures 37a, 37b are precision cast, they have a diameter which is required for mounting on the guiding rods of the carrier member.

Moreover, since elastomeric intermediate sleeves are usually interposed between the guiding rods and the associated surfaces bounding the apertures 37a, 37b, the quality of such surfaces of casting is usually sufficient for co-operation for the intermediate sleeves, without any need for further machining or chamfering.

Figure 4 also shows in detail the projection 28 and its protuberance 28a provided with the flat surface.

While it may be necessary to machine the surface around the threaded bore 29, this again is a machining operation which is easily accomplished, for instance, during the operation resulting in the formation of the threaded bore 29.

The body 3 also has two lateral projections 38a and 38b. These projections 38a and 38b are particularly used during the assembling operation of the brake caliper or of the disc brake assembly, when they may be used for supporting the composite brake caliper on conveyors transporting the brake caliper or the disc brake assembly from one assembling station to another.

Figure 5 illustrates a modified construction of the combination of the actuating cylinder 2 with the support portion 1. The reference numerals used in Figure 5 are the same as in Figures 1 to 4 or only slightly modified relative thereto to facilitate the comparison between these drawings.

The support member 1 of Figure 5 has a support portion 11' which differs from the support portion 11 by being circumferentially incomplete, that is, by extending along only a part of a substantially circular course. The actuating cylinder 2, instead of having the abutment portion 23 discussed above, has abutment portions 23a' and 23b', of which the abutment portion 23b' engages in a recess 18 of the support portion 11' upon assembly of the cylinder 2 with the support member 1. In this construction, the mounting portion 21 will again be received in the support portion 11', and the body 3 will be provided to hold the mounting portion 21 in the open recess bounded by the circumferentially incomplete portion 11'.While it is possible to provide the support portion 11' with the body 3 prior to the assembly with cylinder 2, it is currently preferred to embed the mounting portion 21 and the support portion 11' in the body 3 only after the assembly.

The openings 16a' and 16b' in the brake-shoe operating sections 14a and 14b are shown in Figure 5 as open slots. This greatly facilitates manufacture during the casting of the support member 1. On the other hand, since the sections 14a and 14b will be embedded in the body 3' during the composite caliper manufacturing operation, the open configuration of the opening 16a' and 16b' is not detrimental to the structural integrity of the composite caliper, particularly since the required openings will be bounded by the internal portion 25 of the body 3' in any event, in the same manner as discussed above in connection of Figure 1.

Rather than embedding only the portions 11' and 14a and 14b in two separate bodies 3, the entire support member 1 can be embedded in a continuous single body 3. This is shown in detail in Figure 6, together with some additional modifications. It may be seen that the body 3 has a portion 37 in which the bridge portion 12 is embedded and connecting the portion of the body 3 in which is embedded the support portion 11' and mounting portion 21 with the portion of the body 3 in which is embedded the brake-shoe operating portion 14. The body 3 also has another portion 30 in which is externally embedded the cylinder 2 both at its outer circumferential surface and at its bottom wall.The portion 30 is integrally formed with the projection 38 with its protuberance 38a, and a threaded bore 39 is precision-cast therein at such a location as to be aligned with the bore 29 of the cylinder 2. Hence, a further machining operation or operations are eliminated at the projection 38.

The cylinder 2 of Figure 6 is formed in a deepdrawing operation and is merely machined at its internal surface 24 and, if need be, in the annular seal groove 25. The bore 29 can be stamped out during or subsequent to the deep-drawing operation, in one continuous process.

The abutment portion 23 of the cylinder 2 of Figure 6 is shown to include the seal groove 25, but not the dust-boot recess 26. As indicated in Figure 6 by the reference numeral 37a, the dust-boot recess is formed in the portion 37 of the continuous body 3.

Because of this expedient, it is no longer necessary to machine the surface which peripherally bounds the recess 37a, since it is precision cast during the formation of the body 3.

It is currently preferred to make the support member 1 of a hard cast nodular iron, the cylinder 2 of alloyed steel which is capable of being deep drawn drawn or stamped, and the body 3 of aluminium. However, it will be appreciated that other materials or alloys may also be used instead of the materials mentioned above, as long as such materials satisfy the requirements expected of them, such as the structural strength for the material of the support member 1, the easy shapability of the material of the cylinder 2 coupled with ability to withstand internal pressures, and the mouldability for the material of the body 3 or bodies 3 and 3', and so long as such materials are compatible with one another, that is, so long as they form with one another permanent bonds capable of withstanding without damage the stresses to which they are subjected during the operation of the composite brake caliper. It is to be mentioned that the materials listed above have been found to be ideally suited for this purpose and to satisfy the above-mentioned requirements.

Claims

1. Acaliperfora brake,especiallyafloating- caliper spot-type vehicle brake, comprising a support member of a rigid first material, including a support portion bounding a recess; a separate brake-actuating cylinder of a second material, having a mounting portion received in the recess of the support member; and at least one body of a mouldable third material at least partially covering the support member.

2. A caliper as claimed in claim 1, wherein the first, second and third materials are different metallic materials.

3. A caliper as claimed in claim 2, wherein the first material is iron.

4. A caliper as claimed in claim 2, wherein the first material is cast iron.

5. A caliper as claimed in claim 2, wherein the second material is steel.

6. A caliper as claimed in claim 2, wherein the third material is aluminium.

7. A caliper as claimed in claim 2, wherein the third material is cast aluminium.

8. A caliper as claimed in claim 7, wherein the body has at least one precision cast contact surface thereon.

9. a caliper as claimed in claim 1, wherein the brake-actuating cylinder has at least one precision machined surface thereon.

10. A caliper as claimed in claim 1, wherein at least the support portion of the support member is externally embedded in the body.

11. A caliper as claimed in claim 10, wherein the body has a portion covering the support portion of the support member within the recess and having a precision cast internal contact surface in contact with the mounting portion of the cylinder.

12. A caliper as claimed in claim 11, wherein the contact surface forms an interference fit with the mounting portion.

13. A caliper as claimed in claim 1, wherein at least the mounting portion of the cylinder has a cylindrical outer periphery, and wherein the support portion of the support member has a circumferentially complete annular configuration so that the recess is formed as a cylindrical opening through the support portion.

14. A caliper as claimed in claim 1, wherein the cylinder has at least one abutment portion at the mounting portion extending outwardly beyond the periphery of the cylinder and abutting the composite of the support portion of the support member with the body when the mounting portion of the cylinder is fully received in the recess.

15. A caliper as claimed in claim 1, wherein the support portion of the support member extends along a partly annular course so that the recess has a substantially radially extending opening region, and wherein the body embeds at least both the mounting portion of the cylinder and the support portion of the support member at and around the open region of the recess.

16. A caliper as claimed in claim 1, wherein the support member further includes at least one bridge portion extending from the support portion substantially parallel to the axial direction of the cylinder received in the recess and at a radial offset from such axis and having a free end axially spaced from the support portion, and a brake-shoe operation portion rigid with the free end of the bridge portion and extending substantially normal to and toward the axis, and wherein the operating portion is at least partially embedded in the body.

17. The caliper component as defined in claim 1, wherein the body has at least one opening precisionmoulded therein.

18. A method of manufacturing a caliper for a brake, especially a floating-caliper spot-type vehicle disc brake, comprising the steps of forming a support member of a rigid metallic first material with a support portion bounding a recess, introducing a mounting portion of a separate brake-actuating cylinder of a second material into the recess, and moulding at least one body of a mouldable metallic third material at least onto the support member to cover at least partially the latter.

19. A method as claimed in claim 18, wherein the moulding step includes forming at least one precision surface on the body.

20. A method as claimed in claim 18, wherein the moulding step includes forming at least one precision opening in the body.

21. A method as claimed in claim 18, and further comprising the step of providing at least one precision surface on the cylinder.

22. A method as claimed in claim 21, wherein the providing step includes machining the precision surface on the cylinder.

23. A method as claimed in claim 21,wherein the providing step is performed prior to the introducing step.

24. A method as claimed in claim 18, wherein the moulding step is performed priortothe introducing step.

25. A method as claimed in claim 24, wherein the moulding step includes embedding at least the support portion of the support member in the body, so that the body has a portion lining the recess and supporting the mounting portion of the cylinder therein subsequent to the introducing step.

26. A caliper for a brake substantially as described with reference to the accompanying drawings.

27. A method of manufacturing a caliper for a brake substantially as described with reference to the accompanying drawings.