GB2162260A

GB2162260A - Internally straddled disc brake

Info

Publication number: GB2162260A
Application number: GB08516863A
Authority: GB
Inventors: Rudolf Thiel; Vlad Marianu; Ulrich Klimt
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1984-07-26
Filing date: 1985-07-03
Publication date: 1986-01-29
Also published as: DE3508039C2; IT1185646B; FR2568336B1; GB8516863D0; DE8422260U1; IT8521665A0; DE3508039A1; GB2162260B; JPS6141025A; FR2568336A1

Abstract

In such brake, in particular for automotive vehicles, a brake housing (28) is axially slidably supported at a brake carrier (44) by means of a supporting pin (60) which is stationarily coupled to the brake carrier (44), or to the brake housing (28), and engages a guide bore (66) in the brake housing (28), or in the brake carrier (44), respectively. As shown, one brake lining (38) is supported in guide (82) in carrier (44) while lining (36) is retained at stem (30) of housing (28) by lugs (92). Brake carrier (44) has arms (46, 48) connected through a web (see Fig. 3) while brake housing (28) has a bridge portion (34) connecting stem (30, 32) and furnished with ribs (see Fig. 3). Pin (60) is positioned on the leading side-on the trailing side there is a device (74). Carrier (44) has three fixation points (see Fig. 3) for coupling to a steering knuckle. <IMAGE>

Description

SPECIFICATION Internally straddled disc brake This invention relates to an internally straddled disc brake, in particular for automotive vehicles, with a brake disc which is supported at its outer edge, with a stationary brake carrier, a brake housing which is axially slidably supported at the brake carrier by means of a pin guide and is actuatable by means of an actuating device, which brake housing straddles the internal edge of the brake disc, with two radially extending stems and a substantially axially extending bridge portion connecting said stems, with a first brake lining which is arranged and supported on one side of the brake disc within the brake carrier and can be applied directly by the actuating device, and with a second brake lining which is arranged and supported on the other side of the brake disc at the brake housing and can be applied by the relevant stem of the housing.

Customarily, disc brakes are employed, in particular in automotive vehicles, in which the brake disc is supported at its internal edge and in which the outer edge of the bmke disc is straddled fist-type by the brake housing. In externally straddled disc brakes of this kind, the friction radius of the brake disc is limited in that the bridge portion of the housing is arranged between the outer edge of the brake disc and the wheel rim. It is a further disadvantage of externally straddled disc brakes of this kind that heat problems occur in many cases.

An internally straddled disc brake of the kind mentioned in the beginning is already known from the German patent application published without examination, No.

1,755,391 in which these problems have largely been overcome. In that prior-art disc brake, a brake carrier with two radially outwardly extending arms is provided at the radially external ends of which latter sections are provided which feature a paraxial extension and which, passing below the internal edge of the brake disc, reach to the opposite side of the brake disc. Two brake linings are furnished with radially inwardly directed projections which serve to support the brake linings in the brake carrier. Both the radially inwardly directed projections of the brake linings and the sections of the brake carrier which feature a paraxial extension are formed with semicylindrical openings in which retaining and guide pins extending in axial direction are inserted.The brake housing is furnished with lateral projections provided in pairs which, too, are formed with semicylindrical openings and are guided at the retaining and guide pins. It is a disadvantage of this arrangement that elevated moments come about during braking action, which strongly stress the guides, so that a premature damaging of the guide faces may result which, of course, greatly impairs the functioning of the brake.

Therefore, the invention has as an object to create an internally straddled disc brake of the kind mentioned in the beginning in which the stressing of the guides is lower.

According to the present invention there is provided an internally straddled disc brake, in particular for automotive vehicles, with -a brake disc which is supported at its outer edge, a stationary brake carrier -a brake housing which is axially slidably supported at the said brake carrier by means of a pin guide and is actuatable by means of an actuating device, which said brake housing straddles the internal edge of the brake disc, with two radially extending stems and a substantially axially extending bridge portion connecting said stems, -a first brake lining which is arranged and supported on one side of the brake disc within the said brake carrier and can be applied directly by the actuating device, and -a second brake lining which is arranged and supported on the other side of the brake disc at the said brake housing and can be applied by the relevant stem of the said housing, characterised in that the said pin guide is furnished with a supporting pin configured as a fixed bearing which absorbs any major circumferential forces transmitted by the said second brake lining through the said brake housing to the said guide and which is stationarily coupled to the said brake carrier or to the said brake housing and engages a guide bore in the said brake housing or in the said brake carrier, respectively, and in that the said supporting pin is positioned in the region in which the said brake disc extends in the radial direction.

In this way, an internally straddled disc brake is created in which the forces coming into effect in the circumferential direction during a braking action cannot develop any major moments which would result in an excessive stressing of the guide.

In an advantageous embodiment of the invention the supporting pin is arranged on the leading side relative to the main sense of rotation. Expediently, the arrangement is in this context provided in such a manner that the brake lining positioned on the side of the actuating device is supported directly in the brake carrier, whereas the juxtaposed lining is supported in the brake housing, so that the forces which are transmitted by this lining act, through the brake housing, on the supporting pin and so stress the arm of the brake carrier positioned on the leading side as seen in the main sense of rotation, while the forces which are transmitted by the lining positioned internally stress the brake carrier arm positoned on the trailing side as seen in the main sense of rotation. This will lead to a highly expedient subdivision of forces to the two arms of the brake carrier.

In a further embodiment of the invention, it is envisaged that the supporting pin is fastened to the brake carrier and extends substantially away from the brake disc. In an equally advantageous manner, the supporting pin may, however, alternatively be fastened to the brake housing and extend substantially toward the brake disc. In both these cases, the brake carrier can be positioned very closely to the brake disc, as a result whereof the stresses are reduced still further.

For the purpose of fastening the brake carrier to a component which is stationary with the vehicle, for example to a steering knuckle, the brake carrier is advantageously provided with three points of fixation. Owing to this feature, a web connecting the arms of the brake carrier allows to be dimensioned comparatively weak, so that it contributes but little to the factors to be considered in the radial dimensioning. In particular, the points of fixation at the arm positioned on the leading side are arranged substantially on the same radial line, and two of the points of fixation are arranged substantially on the same radius. The connecting web of the arms of the brake carrier has an arched, particularly a U-shaped configuration and is arranged radially outside the stems of the brake housing.

In order to prevent that residual torques cause the brake housing to rotate around the supporting pin, a device limiting a rotation is provided, according to another embodiment of the invention, between the brake housing and the brake carrier. In particular, the said device is furnished with a pin or a bushing which is fastened to the brake carrier, or to the brake housing, and which engages with play in a bore at the brake housing, or at the brake carrier, respectively. For the purpose of damping, an elastic damping element may be provided in a particularly simple way which is configured in the shape of a rubber bushing and is inserted in the bore in the brake carrier, or in the brake housing, and which is engaged by the pin or by the bushing.

Insertion of the lining supported in the brake carrier is facilitated if the brake carrier is furnished with a guide which is open in the radially outward direction and which serves to receive and support the first brake lining.

In order to achieve an optimised configuration of the brake housing with regard to its weight and strength, the brake housing is provided, according to a preferred embodiment, with a corrugated contour on the inner side in the radial direction, the tangent to the corrugated projections having an outwardly convex configuration in the radial direction.

For the purpose of retaining the internal brake lining related to the actuating device in the radial direction, the lining is furnished with an appropriate device which may be constituted, in particular, by resilient elements projecting into the piston of the actuating device. The resilient elements may particularly be configured as a resilient claw.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a view of an internally straddled disc brake from the inside; Figure 2 is a longitudinal section through an internally straddled disc brake according to Figure 1 and through a vehicle wheel illustrated only in part; Figure 3 is a view as seen from the outside of the internally straddled disc brake illustrated in Figures 1 and 2, with the brake carrier of the disc brake being shown fastened to a steering knuckle of a vehicle; Figure 4 is a view of the internally straddled disc brake from below, and Figure 5 is a view of the internally straddled disc brake from above.

Reference will be made first of all to Figure 2 which shows the arrangement of an internally straddled disc brake 2 in a vehicle wheel 4. In that illustration, only a wheel rim 6 and part of a wheel dish 8 of the vehicle wheel are shown. The vehicle wheel 4 is fastened, through the wheel dish 8 by means of screw bolts 10, to a wheel bearing housing 12. By means of the wheel bearing housing 12, the vehicle wheel 4 is rotatably supported, through a bearing (not shown in the drawing,) on an axle spindle (not shown in the drawing) which is coupled to a steering knuckle. The wheel bearing housing 1 2 is furnished for the purpose with a flange 14 in which threaded bores 1 6 are provided for the screw bolts 10 to be screwed into.A brake disc carrier 1 8 is also fastened to the flange 1 4 by means of the screw bolts 10, with the brake disc carrier 1 8 being arranged between the flange 14 and the wheel dish 8. The brake disc carrier 18 is furnished with a substantially circular ringshaped fastening section 20 positioned radially internally in which bores 21 for the passage of the screw bolts 10 are provided, and with a carrier section 22 which is adapted to the contour of the wheel dish 8. The carrier section 22 forms an end section which extends substantially parallel to the brake axis and to which a connecting ring 24 is fastened. A friction ring 26 is coupled to the connecting ring 24, which friction ring 26 forms the brake disc properly. The internally straddled disc brake 2 is provided with a brake housing 28 which in its longitudinal section has a substantialy U-shaped configuration, the brake housing 28 being furnished with two radially outwardly extending stems 30, 32 which are connected to each other through a bridge portion 34. Brake linings 36, 38 are arranged on either side of the friction ring 26 which is straddled by the U shaped brake housing 28. For the actuation of the disc brake, the stem 32 positioned internally is formed with a cylinder bore 40 within which a piston 42 is axially slidably accommodated. The piston 42 directly applies the brake lining 38 positioned internally, as a result whereof the brake housing 28 is shifted, as a reaction, in the opposite direction, to the inside, so that the lining 36 positioned externally is also applied.

As is seen in particular from Figures 1, 3 and 5, the brake housing 28 is axially slidably supported at a stationary brake carrier 44.

The brake carrier 44 is provided with two brake carrier arms 46, 48 which are connected to each other through a connecting web 50, so that the brake carrier 44 as a whole presents an arched configuration. The brake carrier 44 is coupled to a steering knuckel 52 and is furnished for the purpose with three points of fixation. The points of fixation are configured in the shape of bores 54, 56 and 58 in the brake carrier 44. In this context, two bores 54, 56 are provided at the brake carrier arm 46 which is positioned on the leading side as seen in the main sense of rotation of the disc (wheel) and the other bore 58 at the brake carrier arm 48. The bore 56 positioned internally at the brake carrier arm 46 is located substantially on the same radius as the bore 58 at the brake carrier arm 48 which is positioned on the trailing side.In particular, the two bores 54, 56 provided at the brake carrier arm 46 are substantially positioned on a line intersecting the wheel axle. Bores corresponding to the bores 54, 56, 58 in the brake carrier 44 are provided in the steering knuckle 52, so that the brake carrier 44 allows to be coupled to the steering knuckle 52 by means of screws (not shown in the drawing).

As is revealed particularly by Figure 5, a supporting pin 60 is provided to axially slidably support the brake housing 28 at the brake carrier 44, said supporting pin 60 being stationarily accommodated in a bore 62 of the brake carrier 44, with the latter bore 62 being provided in the brake carrier arm 46 positioned on the leading side as seen in the main sense of rotation. The supporting pin 60 forms a free end projecting from the bore 62 and extending away from the brake disc, said free end constituting a guide surface 64 which interacts with a guide bore 66 provided in the brake housing 28. Between the eye 68 of the brake carrier 44 containing the bore 62, on one side, and the eye 70 of the brake housing 28 containing the guide bore 66, on the other side, a dust cover 72 is provided for the protection of the guide surface 64.

On the trailing side as seen in the direction of the main sense of rotation, a device 74 is provided serving to absorb the moments occurring around the supporting pin 60 during braking action. The device 74 is furnished with a short pin 76 which is screwed into the brake carrier arm 48 and extends parallel to the supporting pin 60, away from the brake disc. The pin 76 engages a bore 78 provided in the brake housing 28.

In this configuration, the diameters of the bore 78 and of the pin 76 are sized such that a free annular space remains in between. A rubber bushing 80 is interposed within that annular space in order to damp the motions of the pin 76 within the bore 78 coming about during braking. Other damping elements made of other materials with damping properties may be provided as an alternative, instead of the rubber bushing 80.

For the purpose of supporting the internal brake lining 38 in the brake carrier 44, the latter forms a guide 82 which is bounded by supporting surfaces 84, 86 in peripheral direction. As is seen particularly from Figure 5, the supporting surfaces 84, 86 are provided in this configuration in the region of the supporting pin 60 and of the pin 76. For the retainment of the internal brake lining 38 in the radial direction, the latter is furnished with resilient tongues 88 which engage the interior of the piston 42. For the retainment of the external lining 36 at the external stem 30 of the housing 28, the stem 30 is formed with two shoulders 90, one of which only being illustrated in Figure 3. The external brake lining 36 is furnished on its reverse with two axially projecting lugs 92 through which it takes support on the shoulders 90 of the brake housing 28.Owing to this configuration, the brake linings 36, 38 allow to be inserted radially from the outside in a simple manner. For this purpose, the brake housing 28 is first of all pushed in the inward direction (to the right in Figure 2), so that the internal brake lining 38 can be inserted. Subsequently, the brake housing 28 is pushed in the outward direction (to the left in Figure 2), so that the external lining 36, too, can be inserted into the brake housing 28 through openings (not shown in the drawing) which are provided in the brake disc carrier 18,.

without the brake disc 26 requiring to be unmounted for the change of the brake linings.

The brake housing 28 is furnished with ribs 94 in the range of the bridge portion 34 and of the radially internal sections of the stems 30, 32. The tangent to the peaks of these ribs 94 forms a radially outwardly curved surface, so that the ribs 94 located externally in circumferential direction are higher than the ribs located internally. In this way, the brake housing 28 is given an increased cross-sectional area in those ranges which have to undergo particular stresses.

The following is a brief description of the method of functioning of the internally straddled disc brake 2. For the actuation of the disc brake 2, pressure medium is fed into the cylinder chamber 96 through a connection (not shown in the drawing). As a result, the piston 42 is shifted axially in the direction of the brake disc 26. The piston 42 so applies the brake lining 38 positioned internally urging it against the brake disc 26. As a reaction to that, the brake housing 28 is shifted inwardly, that is to say, to the right in Figure 2 and urges the external brake lining 36 against the brake disc 26. On the release of the brake, the fluid within the chamber 96 becomes unpressurised, so that, with the aid of a roll-back seal 98, the piston 42 is made to return a slight distance into the cylinder bore, dragging along with it the internal brake lining 38.

Claims

1. An internally straddled disc brake, inparticular for automotive vehicles, with -a brake disc which is supported at its outer edge, -a stationary brake carrier -a brake housing which is axially slidably supported at the said brake carrier by means of a pin guide and is actuatable by means of an actuating device, which said brake housing straddles the internal edge of the brake disc, with two radially extending stems and a substantially axially extending bridge portion connecting said stems, -a first brake lining which is arranged and supported on one side of the brake disc within the said brake carrier and can be applied directly by the actuating device, and -a second brake lining which is arranged and supported on the other side of the brake disc at the said brake housing and can be applied by the relevant stem of the said housing, characterised in that the said pin guide is furnished with a supporting pin (60) configured as a fixed bearing which absorbs any major circumferential forces transmitted by the said second brake lining (36) through the said brake housing (28) to the said guide and which is stationarily coupled to the said brake carrier (44) or to the said brake housing (28) and engages a guide bore (66) in the said brake housing (28) or in the said brake carrier (44), respectively, and in that the said supporting pin (60) is positioned in the region in which the said brake disc (26) extends in the radial direction.

2. An internally straddled disc brake as claimed in claim 1, characterised in that relative to the main sense of rotation of the said brake disc, the said supporting pin (60) is arranged on the leading side.

3. An internally straddled disc brake as claimed in calim 1 or claim 2, characterised in that the said supporting pin (60) is fastened to the said brake carrier (44) .and extends substantially away from the said brake disc (26).

4. An internally straddled disc brake as claimed in claim 1 or claim 2, characterised in that the said supporting pin (60) is fastened to the said brake brake housing (28) and extends substantially toward the said brake disc.

5. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that the said brake carrier (44) is furnished with two brake carrier arms (46,48).

6. An internally straddled disc brake as claimed in claim 5, characterised in that the two said brake carrier arms (46, 48) are connected to each other through a connecting web (50).

7. An internally straddled disc brake as claimed in claim 6, characterised in that the said connecting web (50) has an arched, particularly a U-shaped configuration.

8. An internally straddled disc brake as claimed in claim 6 or claim 7, characterised in that the said connecting web (50) is arranged radially outside the said stems of the said housing (28).

9. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that the said brake carrier (44) is provided with three points of fixation (54, 56, 58) for the purpose of coupling it to a component which is stationary with the vehicle.

1 0. An internally straddled disc brake as claimed in claim 9 as appendant to claim 5, characterised in that two of the said points of fixation (54, 56) are provided at the said brake carrier arm (46) which is positioned on the leading side as seen in the direction of the main sense of rotation of the brake disc.

11. An internally straddled disc brake as claimed in claim 10, characterised in that the said points of fixation (54, 56) at the said brake carrier arm (46) positioned on the leading side are arranged substantially on the same radial line.

1 2. An internally straddled disc brake as claimed in any one of claims 9 to 11, characterised in that two of the said points of fixation (56, 58) are arranged substantially on the same radius.

1 3. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that between the said brake housing (28) and the said brake carrier (44), a device (76, 78, 80) is provided limiting a rotation around the said supporting pin (60) caused by the forces which occur during a braking action.

14. An internally straddled disc brake as claimed in claim 13, characterised in that the said device for the limitation of a rotation of the said brake housing (28) is furnished with a pin (76) which is fastened to the said brake carrier (44), or to the said brake housing (28), and which engages with play in a bore (78) at the said brake housing, or at the said brake carrier, respectively.

1 5. An internally straddled disc brake as claimed in claim 1 3 or claim 14, characterised in that the said device (76, 78, 80) for the limitation of a rotation of the said brake housing (28) is provided with an elastic damping element (80).

1 6. An internally straddled disc brake as claimed in claim 15, characterised in that the said elastic damping element (80) is a rubber bushing which is inserted in the said bore (78) in the said brake carrier (44), or in the said brake housing (28), and which is engaged by the said pin (76).

1 7. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that the said brake carrier (44) is furnished with a guide which is open in the radially outward direction and which serves to receive and support the first brake lining (38).

1 8. An internally straddled disc brake as claimed in claim 17, characterised in that the said guide is constituted by supporting surfaces (84, 86) which are arranged at least in part within the region of the said supporting pin (60) as seen in the radial direction.

1 9. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that the said brake housing (28) is provided with ribs (94) on the inner side in the radial direction.

20. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that on the inner side in the radial direction, the said brake housing (28) is furnished with a contour which is arched radially outwardly.

21. An internally straddled disc brake as claimed in any one of the preceding claims, characterised in that the first brake lining (38) positioned on the side of actuation is furnished with a device (88) with which it enters into engagement with the actuating device, in particular at the piston (42).

22. An internally straddled disc brake as claimed in claim 21, characterised in that the engagement device is a resilient claw which is furnished with elastic tongues (88).

23. An internally straddled disc brake substantially as herein described with reference to and as illustrated in the accompanying drawings.