WO2005073586A1

WO2005073586A1 - Disc brake design

Info

Publication number: WO2005073586A1
Application number: PCT/SE2005/000083
Authority: WO
Inventors: Lars Severinsson
Original assignee: Haldex Brake Products Ab
Priority date: 2004-01-28
Filing date: 2005-01-26
Publication date: 2005-08-11
Also published as: SE0400162D0; EP1711722A1

Abstract

The present invention concerns a disc brake for vehicles. The brake comprises one or more brake discs (2), one or more brake pads (3) placed on each side of the brake disc(s) (2) and at least one brake actuator (4, 5). The brake actuator (4, 5) acts on thrust units (10, 11) by means of at least one lever (7, 21). The at least one brake actuator (4, 5) is displaced in relation to the rotational axis of the brake disc(s) (2). The displacement may be lateral or angular in relation to the rotational axis.

Description

DISC BRAKE DESIGN Technical Field The present invention concerns the design of a disc brake for vehicles and more specifically the placing of the brake actuator. The invention is developed for heavy-duty vehicles, but a person skilled in the art realises that it may be used for any type of vehicle.

Prior Art In disc brakes the caliper is either fixed or floating and the same goes for the brake disc(s) . Often the caliper is fixed if the brake disc(s) are floating and vice versa. In other embodiments both the caliper and the disc(s) are fixed. In yet other embodiments one of the caliper and the disc(s) are fixed while the other part is semi-fixed. This invention could be used with any combina- tion of fixed, semi-fixed or floating caliper or brake disc (s) . For disc brakes it is common to place the service brake actuator and a possible integrated parking brake actuator centrally in view of the brake disc or discs, and having the same general extension as the rotational axis of the brake disc(s). The actuator is often placed somewhat higher than the rotational axis of the disc(s). In many vehicles the available space for the brake and brake actuators is limited. In some cases there is not enough room for brakes of standard design and with the braking effects needed. Thus, there is a need to be able to adapt the design of the brake in view of the available space. Summary of the Invention In some trucks or the like the available space may not be enough to have the actuator (s) placed centrally in relation to the brake disc(s). However, sometimes there is free space to the side of the main part of the disc brake. In other cases it may be enough to turn the actuator to a position showing an angle to the rotational axis of the brake disc(s). Often it is turned to a vertical position. According to the present invention the brake actuator may be placed displaced in relation to the rotational axis of the brake disc(s). The displacement may be a lateral displacement and/or an angular displacement. As used in this description "lateral displacement" is in relation to the rotational axis of the brake disc(s) and correspond to a displacement forward or backward of the vehicle in which the brake is mounted. "Angular displacement" as used in this description is also in relation to the rotational axis of the brake disc(s). Often an actuator for a parking brake is integrated in the actuator for the service brake. In other examples the actuator for the parking brake is separated from the actuator for the service brake. By placing the actuator or actuators laterally and/or angularly displaced from the rest of the brake it is possible to fit in a brake where it would be impossible with a brake of traditional design. In some embodiments it may be enough to displace only the parking brake actuator, while the service brake actuator remains in a traditional position. In still further embodiments it is possible to displace both the parking brake and service brake actuators and possibly in different positions in relation to the rotational axis of the brake disc. The displacement of the actuator (s) is made possible in that the thrust units are operated by means of a common lever to which the actuator is attached. Normally the ac- tuator acts by means of the lever on thrust units. Said units act to get the brake pads and brake disc(s) into contact to accomplish a braking. While the position of the brake disc is more or less dictated by the position of the wheel axle or similar part, the position of the actuator may be varied. By extending the lever it is possible to displace the service brake actuator and/or parking brake actuator . The exact design of the brake may vary within relatively wide ranges. Further objects and advantages of the present invention will be obvious to a person skilled in the art when reading the detailed description below of preferred embodiments . Brief Description of the Drawings Different embodiments of the invention will be described in more detail below, with reference to the enclosed drawings and by way of examples. In the enclosed drawings : Fig. 1 is a schematic side and plan view of a first embodiment comprising the present invention; Figs. 2a and 2b are schematic side and plan views corresponding to Fig. 1 of second and third embodiments comprising the present invention; Fig. 3 is schematic views corresponding to the previous Figs, of a fourth embodiment comprising the present invention; Fig. 4 is schematic views corresponding to the previous Figs, of a fifth embodiment comprising the present invention; Fig. 5 is a schematic side and plan view of a parking brake actuator comprising the present invention; and Fig. 6 is a schematic side and plan view of a parking brake actuator comprising the present invention. Detailed Description of Preferred Embodiments One example of a brake in which the present invention is used is shown in Fig. 1. The brake comprises a caliper 1 and at least one brake pad 3, placed on each side of a brake disc 2. The brake pads 3 act in opposing directions on the brake disc 2. In this example both the caliper 1 and the brake disc 2 are fixed, i.e. they are not to slide in relation to each other. An actuator 4 is furnished for the service brake and an actuator 5 for a parking brake is integrated in the actuator 4 for the service brake. The actuator 4 for the service brake has a piston 6 attached to a lever 7. The lever 7 is fixed to a mechanism housing 8 in such a way that the lever may be turned around a rotational axis 9. The mechanism housing 8 receives the lever 7 and thrust units 10, 11. As shown here it is a distance between the caliper 1 and the mechanism housing 8. The brake pads 3 are received on brackets 28 in the caliper 1, which brackets 28 will take up braking force from the pads 3. In the shown embodiment the mechanism housing 8 and the caliper 1 are separate parts, but in other embodiments the caliper 1 and the mechanism housing 8 are integrated in one part. Even tough the mechanism housing 8 is shown as one unit, in other embodiments the part of the housing receiv- ing the actuator 4, 5 is a separate module. Such a separate module is then bolted to the rest of the housing and assists in taking up the braking force. By the modular form of the mechanism housing it is relatively easy to adapt the design of the brake to different vehicles. In the shown embodiment four thrust units are attached to the lever 7. Said thrust units have the form of screw units 10, 11. Two of said screw units 10 acts to push the brake pad 3 on the same side of the disc 2 against the brake disc 2. The other two screw units 11 acts on the brake pad 3 on the opposite side of the brake disc 2 by means of a pull beam 12. The screw units 10, 11 are attached to the lever 7 in pivots 13, 14. The part 15 of the lever 7 to which the screw units 10, 11 are attached has the form of a crankshaft. The screw units 10, 11 are at- tached to the crankshaft 15 in such a way that they work in opposite directions. Thus, the screw units 10 acting on the brake pad 11 on the same side of the disc 2 are acting in a pushing direction. The screw units 11 acting on the brake pad 11 on the opposite side of the disc 2 are acting in a pulling direction by means of the pull beam 12. The pivots 13 of the pulling screw units 11 are attached to a crank of the lever 7 placed on the opposite side of the rotational axis 9 compared to the actuator 4. The pivots 14 of the pushing screw units 10 are placed on the same side of the rotational axis 9 as the actuator 4. The crankshaft 15 of the lever 7 is journaled in two bearings 16, 17, one at each end. The bearings 16, 17 are received in walls of the mechanism housing 8. The rotational axis 9 of the crankshaft 15 is aligned with the bearings 16, 17. If needed, further bearings (not shown) are placed at different positions along the crankshaft 15. In normal fashion an adjusting mechanism 18 is connected to one screw unit 10, to adjust the position of the brake pads 3 due to the wear of the brake pads 11. A synchronisation device 19 connected to the screw units 10, 11 is used to synchronise the movements of the screw units 10, 11 during adjustment. The synchronisation device 19 may be of the type having a chain, belt or gear transmission or a common shaft, mainly parallel with the brake disc 2 and having bevelled or worm gears to respective screw unit 10, 11. The brake actuator 4, 5 is placed laterally displaced in relation to the main part of the brake. The actuator 4, 5 is attached to an extended, lateral part of the crank- shaft 15 of the lever 7. The shown orientation of the brake actuator 4, 5 is only one example, a person skilled in the art realises that the actuator 4, 5 may have any orientation along a full circle. The length of the extended part of the crankshaft 15 may also vary, depending on where it is possible to place the brake actuator 4, 5. During braking the piston 6 of the actuator 4 will act on the lever 7, pushing it to the left as shown in the side view of Fig. 1. The lever 7 will then rotate around the rotational axis 9 in the bearings 16, 17. By the rota- tion of the lever 7 and its crankshaft 15 the screw units 10 acting on the brake pad 3 on the same side of the brake disc 2 will be forced to act in a pushing direction, pushing the brake pad 3 against the disc 2. In the same manner the screw units 11 acting on the brake pad 3 on the oppo- site side of the brake disc 2 by means of the pull beam, will be forced in the pushing direction, pushing that brake pad 3 against the brake disc 2. Thus, the pads 3 being pressed against the brake disc 2 give the braking action. Both the brake disc 2 and the caliper 1 are of the fixed type in this case. The parking brake actuator 5 is integrated in the service brake actuator 4 and acts directly on the service brake actuator 4, in a manner known to a person skilled in the art. The embodiments of Figs. 2a and 2b corresponds to the embodiment of Fig. 1 except in that in braking the brake force is only acting directly on the brake pad 3 on one side of the brake disc 2. The only difference between the embodiments of Figs. 2a and 2b is which screw units 10, 11 that are connected to the crankshaft part 15 of the lever 7. In these embodiments either the caliper 1 or the brake disc 2 is fixed while the other part is semi-fixed, i.e. it is elastic in itself or elastically mounted in such away that the play between disc and pad as well as the elasti- city of the parts and there mounting will be taken up at braking. Corresponding parts are given the same reference numbers throughout this description. A person skilled in the art realises that the exact design of the different parts may vary even if they are given the same reference numbers. In Fig. 2a the brake force is applied to the same side of the brake disc 2 as the screw units 10 are placed, in that the screw units 10 are attached to the crankshaft 15. The other two screw units 11 are not connected to the lever 7. However, all screw units 10, 11 are connected to the adjusting mechanism 18 by means of the synchronisation device 19. Thus, the position of the brake pads 3 on both sides of the brake disc 2 is adjusted in relation to the brake disc 2 and in respect of the wear of the pads 3. In the embodiment of Fig. 2b the screw units 11 acting on the brake pad 3 on the opposite side of the brake disc 2 are attached to the lever 7. In both embodiments, the elasticity of the caliper 1, the brake disc 2 and/or the mounting of said parts is such, that the brake force acting on the brake pad 3 on one side of the brake disc 2, will make the brake disc 2 to go into contact with the other brake pad 3. This is made easier by the pads 3 being mounted on the brackets 28 and that the caliper 1 is separated from the mechanism housing 8. In the embodiment of Fig. 3 the laterally displaced actuator 4, 5 is used for a brake having a fixed caliper 1 and a floating brake disc 2. In this case screw units 10 are only placed to act directly on the closest brake pad 3. During braking the closest brake pad 3 will be pressed against the brake disc 2, which is pressed against the brake pad 3 on the opposite side of the brake disc 2. The adjustment mechanism 18 keeps a correct distance between the brake pads 3 and the brake disc 2 regarding wear of the brake pads 3. In the embodiment of Fig. 4 the laterally displaced actuator 4, 5 is used in a brake having a fixed brake disc 2 and a floating caliper 1. In this case the caliper 1 will slide during braking when the screw units 10 act directly on the brake pad 3 on the same side of the brake disc 2.

The movement of the caliper 1 during braking will force the brake pad 3 on the opposite side of the brake disc 2 into contact with the disc. In the embodiments of Figs. 5 and 6 the parking brake actuator 5 is separated from the service brake actuator 4. In the shown embodiments the service brake actuator 4 has a traditional central position, while the parking brake actuator 5 has a laterally displaced position. A person skilled in the art realises that if needed both the service brake actuator 4 and the parking brake actuator 5 may be laterally displaced, possibly to different lateral positions. It is also possible to have both actuators 4, 5 at the same laterally displaced position but at different angles . In the embodiment of Fig. 5 the parking brake actuator 5 has a separate mechanism received in a parking brake mechanism housing 24. A piston 20 of the actuator 5 acts on a lever 21, which lever 21 is journaled in bearings 26, 27 giving the lever 21 a rotational axis 23. The bearings 26, 27 are received in walls of the parking brake mechanism housing 24. The lever 21 has a part resembling a crankshaft 25. Each screw unit 10 is attached to the crankshaft 25 by means of an arm 29 and a pivot 22. The pivots 22 are placed on a crank on the same side of the rotational axis 23 as the actuator 5. The crankshaft 25 is extended to make it possible to laterally displace the parking brake actuator 5. In this case the parking brake is applied in that the motion of the piston 20 of the actuator 5 is transferred to the screw units 10 by means of the crankshaft 25 and the arm 29. In the embodiment of Fig. 6 the parking brake actuator 5 is acting on the same lever 7 as the service brake actuator in spite being placed in different positions. The lever 7 has a further part attached to the piston 20 of the parking brake actuator 5. The further part to which the piston 20 is attached is fixed to an extended part of the crankshaft 15. The screw units 10 are attached to the crankshaft 15 by means of pivots 14. Said pivots 14 are placed on the same side of the rotational axis 9 as the service brake actuator 4. A separated parking brake actuator 5 may be used for any of the embodiments shown in the Figs. 1-4. The shown embodiments are only examples of use of the present invention and a person skilled in the art realises that it may be used with many different types of brakes. Thus, the exact design of the brakes is of no importance for the use of the present invention.

Claims

CLAIMS 1. A disc brake comprising one or more brake discs (2), one or more brake pads (3) placed on separate sides of the brake disc and at least one brake actuator (4, 5), acting on thrust units (10, 11) by means of at least one lever (7, 21), characterized in that at least one brake actuator (4, 5) is displaced in relation to a rotational axis of the brake disc (2) .

2. The disc brake of claim 1, characterized in that the at least one brake actuator (4, 5) is laterally displaced.

3. The disc brake of claim 1 or 2, characterized in that the at least one brake actuator (4, 5) is extended at an angle to the rotational axis of the brake disc(s) (2) .

4. The disc brake of any of the previous claims, characterized in that the brake actuator comprises an integrated service brake actuator (4) and parking brake actuator (5) or that it has a service brake actuator (4) and a parking brake actuator (5), which are separated from each other.

5. The disc brake of claim 4, characterized in that the service brake actuator (4) and the parking brake actuator (5) are separated but placed at the same lateral position.

6. The disc brake of any of the previous claims, characterized in that the lever (7, 21) has the form of a crankshaft received in bearings (16, 17, 26, 27) in such a way that the lever (7, 21) may be rotated around a rotational axis (9, 23) .

7. The disc brake of claim 6, characterized in that the bearings (16, 17, 26, 27) are received in walls of a mechanism housing (8, 24), in which mechanism housing (8, 24) the thrust units (10, 11) and the lever (7, 21) are received.

8. The disc brake of any of the previous claims, characterized in that the lever (7, 21) has an extended part to which the piston (6, 20) of the actuator (4, 5) is attached in a position laterally displaced from the rest of the disc brake.

9. The disc brake of any of the previous claims, characterized in that the service brake actuator (4) and the parking brake actuator (5) are attached to the same lever (7 ) .

10. The disc brake of any of the claims 1 to 8, characterized in that the service brake actuator (4) and the parking brake actuator (5) are attached to separate levers (7, 21) .

11. The disc brake of any of the previous claims, characterized in that the thrust units (10, 11) have the form of screw units attached to the lever (7, 21) on the same or opposite side of the rotational axis (9, 23) of the lever (7, 21) as the brake actuator (4, 5).

12. The disc brake of claim 11, characterized in that the screw units (10, 11) act in opposing direction depending on if they are attached on the same or opposite side of the rotational axis (8, 23) of the lever (7, 21) as the actuator (4, 5).

13. The disc brake of any of the previous claims, characterized that it has a fixed caliper (1) and one or more fixed brake discs (2); that it has fixed caliper (1) and one or more semi-fixed brake discs (2); that it has a semi-fixed caliper (1) and one or more fixed brake discs (2); that it has a fixed caliper (1) and one or more floating brake discs (2); or that it has a floating caliper (1) and a fixed brake disc (2) .