CN112196921A

CN112196921A - Brake actuating mechanism and disc brake and manufacturing method

Info

Publication number: CN112196921A
Application number: CN202010646129.5A
Authority: CN
Inventors: S·桑德伯格
Original assignee: Haldex Brake Products AB
Current assignee: Haldex Brake Products AB
Priority date: 2019-07-07
Filing date: 2020-07-07
Publication date: 2021-01-08
Also published as: DE102019004673A1; DE102019004673B4

Abstract

The invention relates to a brake actuating mechanism for a disc brake, wherein a translational movement in the direction of a brake disc causes an input element of an adjusting device (B) to rotate, wherein the input element of the adjusting device (B) is formed as part of a ball screw transmission (7). The invention also relates to a disc brake comprising a brake actuating mechanism of this type.

Description

Brake actuating mechanism and disc brake and manufacturing method

Technical Field

The present invention relates to a brake actuating mechanism for a disc brake and a disc brake, in particular to a utility vehicle having such a brake actuating mechanism. In addition, the invention relates in particular to a method for producing a partial assembly of a brake actuating mechanism.

Background

In this context, the invention covers disc brakes having a sliding caliper or a fixed caliper and overlapping one or more brake discs. The present invention relates generally, but not exclusively, to disc brakes having point type pad segments.

Disc brakes, in particular for heavy duty trucks, are known in various designs relating to the type of brake actuating mechanism, the way in which the braking force is transmitted to one or more brake discs and the way in which the brake pads are adjusted to compensate for wear.

A particular embodiment of a brake actuation device for a disc brake is known, for example, from the applicant's international application WO 2011/113554 a 2. The brake actuation mechanism known in this application is characterized by an extremely compact design which requires less space in the caliper housing and is lighter. All components of such a brake actuating mechanism are mounted together in a functionally cooperating manner in the caliper by means of a rod mounted in the caliper housing in the axial direction, so that they act parallel to the axis of rotation of the brake disc. Due to the displacement movement of the amplification mechanism, the thrust element performs a translational movement together with the adjusting device in the direction of the brake disk in order to transmit the clamping force.

The adjusting device for wear compensation has a torque clutch which is torque-controlled and is used to selectively transmit rotation depending on the direction of rotation between the components of the torque clutch. In addition, the regulator comprises a one-way clutch in which two elements (inner sleeve and hollow spindle shaft) rotatably mounted on a lever are connected to each other by means of a freewheel spring, the one-way clutch being designed such that it transmits a rotational movement between these two elements during brake actuation and slips when the brake is released.

With regard to the exact function of the prior art brake actuating mechanism of clamping and braking force transmission and adjustment movement, reference is hereby made explicitly to the disclosure of WO 2011/113554 a 2. Other brake actuating mechanisms of similar design are known from, for example, WO 2013/083857 a2, WO 2014/106672 a2 or WO 2015/140225 a2 of the applicant, which are also expressly referred to herein.

Common to the above mentioned prior art brake actuation mechanisms is that the spindle hollow spindle, which is rotatably mounted on a rod, serves as an input element of the adjustment device and immediately starts rotating under the action of the lever of the amplification mechanism. For this purpose, a pin or the like is provided at a suitable point on the hollow spindle of the spindle, which pin projects radially from the hollow spindle of the spindle and is received by a recess in the lever in the region of its pivot-bearing surface with a defined clearance. This allows the spindle hollow spindle to start rotating due to the pivoting movement of the lever, which is then introduced into the adjusting device.

However, in the case of frequent brake actuations (such as may occur in public transport buses), the wear suffered by the connection between the pin and the recess may increase, which is undesirable for reasons of functional safety and service life.

In order to improve functional safety and reduce wear of the adjusting device for such a disc brake while compactly designing the disc brake, the applicant's international patent application WO 2018/015565 a1 proposes a disc brake with a brake actuating mechanism in which the input element of the adjusting device is designed as part of a ball screw transmission. Furthermore, it is known from german utility model DE 202018002963.7 of the applicant to limit the circumferential travel of the balls of such a ball screw transmission by means of stops on the outer ring of the screw or spindle. However, in some cases, the balls may get stuck in the stopper.

The invention relates to a further development of such a brake actuating mechanism, the object of which is to further improve the functional safety of the adjusting device.

Disclosure of Invention

For this purpose, the invention proposes a brake actuating mechanism and a disc brake having such a brake actuating mechanism. Furthermore, the invention proposes a method for producing an assembly for a ball screw drive for such a brake actuating mechanism.

In general, regardless of the principle of the specific configuration of the brake actuating mechanism and the adjusting device implemented therein, the core of the present invention is to provide a brake actuating mechanism for a disc brake, comprising:

-an amplification mechanism which introduces clamping force for brake operation;

-a thrust element transmitting said clamping force onto the brake disc;

the amplification mechanism and the thrust element cooperate such that the thrust element performs a translational movement towards the brake disc due to a displacement movement of the amplification mechanism; and

-adjustment means for compensating for pad wear,

wherein an input element of the adjusting device, which input element is formed as a spindle of the ball screw drive, can be set into rotation as a result of the translatory movement, wherein the balls are guided in a plurality of parallel outer rings of the threaded section of the spindle and in a plurality of parallel inner rings of a nut of the ball screw drive, which outer and inner rings are open on both sides of the ball screw drive and are each provided with a stop, which limits the circumferential path of the balls, and wherein the stops are formed by disk-shaped elements.

In the sense of the present invention, the disc-shaped element should be a substantially annular disc having a through hole for the spindle to pass through.

Since the inner ring and the outer ring are provided with disk-shaped stops in the region of their ends, the balls which can be arranged in the ball cage run along the disk-shaped stops, so that the circumferential travel of the balls and thus the extent to which the spindle can rotate is limited. In addition, this prevents the balls from falling out of the inner race and the outer race in the assembled state. In summary, thanks to the measure of the invention, the unit consisting of the nut and the spindle can be better held together from a functional point of view.

In a further development of the brake actuating mechanism, the disc-shaped elements are mounted so as to be freely movable in the axial direction of the ball screw transmission, i.e. they are neither rigidly nor rotationally fixed on the spindle or nut.

According to the invention, a first washer or disc-shaped element is connected to the spindle and spaced from the nut, whereby preferably the first disc-shaped element is formed in a shape conforming to the contour of the outer ring of the threaded section and is guided therein. The first disc-shaped element is therefore mounted at least to some extent rotatably in an external thread of the ball screw drive, which external thread is formed by the outer ring.

The outer rings may each have, on their stop-side end, an abutment against which the first disc-shaped element rests, these abutments preferably being formed by plastic deformation of the material of the spindle, as described below in connection with the manufacturing method.

Similarly, according to the invention, a second washer or disc-shaped element is provided, which is connected to the nut and is spaced apart from the spindle, and is also preferably shaped to conform to the contour of the inner ring of the nut and guided therein. The second disc-shaped element is thus at least to some extent rotatably mounted in an internal thread of the ball screw drive, which internal thread is formed by the inner ring.

Likewise, the inner ring can also have an abutment at each of its stop ends, against which the second disc-shaped element rests, whereby these abutments are also preferably formed by plastic deformation of the material of the nut.

In the case of a relative movement between the spindle and the nut within the framework of the adjusting movement of the brake actuating mechanism, the balls travel relative to the disc-shaped element or come into contact with the disc-shaped element when reaching the final position.

If, in an advantageous embodiment, an abutment is also provided on the outer or inner ring, this will result in the disc-shaped element then resting on this abutment, which will ultimately limit the circumferential travel of the balls. In the opposite direction of rotation, the balls can easily be separated from the disc-shaped element again, since they only contact the flat surface of the disc-shaped element. If, as in the prior art, an integral stop is provided only at the end of the ball race, there is sometimes a risk of the balls catching at the stop due to the forces occurring in such brake actuation mechanisms.

In order to set the target adjustment behavior, according to the invention, the ball screw drive can be influenced by changing the number and/or the inclination angle of the outer ring of the spindle and/or the inner ring of the nut. In particular, the outer ring of the spindle and/or the inner ring of the nut may have a varying pitch.

In an advantageous embodiment of the brake actuating mechanism according to the invention, the outer ring of the spindle and/or the inner ring of the nut are designed such that a first adjustment is effected by the adjusting device at low rotational speeds of the spindle and a further adjustment exceeding this first adjustment is effected at higher rotational speeds of the spindle.

The brake actuating mechanism according to a further embodiment of the invention can be designed such that the input element of the adjusting device cooperates directly or indirectly with the torque clutch to achieve a more compact design and can furthermore be designed such that the amplification mechanism, the thrust element and the adjusting device can be mounted in a functionally cooperating manner in the brake caliper by means of a rod which is mounted in the housing of the brake caliper of the disc brake so as to be immovable and non-rotatable in the axial direction, the input element of the adjusting device being designed as a hollow spindle of a ball screw drive which is rotatably mounted on the rod.

The advantage of using a ball screw transmission is primarily that the mechanism has less friction and therefore less wear. The lower transmission power required as a result in combination with the possibility of higher displacement speeds is particularly advantageous for the adjustment means, since they allow a more precise adjustment of the position when less force is expended to compensate for wear-related clearances.

Since the ball screw transmission converts a translational movement into a rotation, according to the invention, a forward movement of the thrust element on the brake disc can be used to cause a rotation in the ball screw transmission. The low internal friction of the ball screw drive is an advantage here, since even if a linear pressure or thrust is applied to the spindle serving as the input element of the adjusting device, the nut or the spindle is caused to rotate depending on which elements are located in the adjusting device in a rotationally fixed manner.

This makes it possible to mechanically disengage the amplification mechanism or the components of the amplification mechanism acting on the adjustment device or its input element when the brake is applied and, if necessary, when the brake is released. Without direct mechanical connection by means of prior art coupling elements such as pins and recesses, this brake actuation mechanism suffers from reduced wear and exhibits a longer service life.

The main thing of the brake actuator is that the ball screw drive of the adjusting device can be configured and adjusted independently for the desired adjusting action, taking into account the other design of the adjusting device and the brake actuator, whereby for this design a targeted influence is exerted on the type of thread to be used, such as the type of groove or ball ring and ball, the shape of the thread, etc.

The invention also relates to a disc brake having a brake actuation mechanism as in at least one of the embodiments described above. In particular, the invention relates to a disc brake in which a brake actuating mechanism designed according to at least one of the above-described embodiments can be mounted in a housing of a brake caliper of the disc brake at least in modules under the action of a lever or integrally as a self-supporting unit.

The invention further relates to a production method, by means of which components of a ball screw drive, in particular components for a brake actuator, can be produced in a simple manner in one of the above-described embodiments.

Accordingly, in a first aspect of the present invention, there is provided a method of manufacturing a lead screw or spindle for a ball screw transmission, in particular for a brake actuator, the method comprising the steps of:

-forming the spindle base body so as to form, at least one end face, a conical collar tapering in the axial direction,

at least sectionally, forming or introducing outer rings on the outer surface of the main shaft base body, which outer rings extend into the shaft ring with lugs formed on the respective outer ring, and

-pressing the front end of the spindle base against the abutment so that the lugs constrain the outer ring in the event of plastic deformation, i.e. narrowing of the cross-section.

In another aspect of the present invention, there is provided a method of manufacturing a nut for a ball screw transmission, in particular for a brake actuator, the method comprising the steps of:

-forming a nut base body with a through hole such that at least one end face of the through hole is formed with a conical collar tapering in an axial direction,

at least sectionally forming or introducing an inner ring on the inner surface of the through-bore, which inner ring extends into the shaft ring with lugs formed on each inner ring, and

-pressing the front end of the nut base against the abutment so that the lugs constrain the inner ring in the event of plastic deformation.

The bead-like constriction resulting from the plastic deformation forms an abutment which can then serve directly as a stop for the balls of such a ball screw transmission, however, according to the invention, it should preferably serve as a boundary against which the disk-shaped element according to the invention can rest.

Drawings

Further advantages and features of the invention are obtained from the following description of embodiments shown in the drawings, in which:

fig. 1 is a longitudinal section in the axial direction of a brake actuating mechanism according to the prior art;

FIG. 2a is an exploded view of the brake actuation mechanism in a first view;

FIG. 2b is an exploded view of the brake actuation mechanism in another view;

FIG. 3 is a longitudinal section through FIG. 1, including a detail of the section;

FIG. 4a is a cross-section along M-M in FIG. 3;

FIG. 4b is a cross-section along N-N in FIG. 3;

FIG. 4c is a cross-section along O-O in FIG. 3;

FIG. 5 is a longitudinal section of FIG. 1, with further details of the section;

FIG. 6a is a cross-section taken along P-P in FIG. 5;

FIG. 6b is a cross-section along Q-Q in FIG. 5;

FIG. 6c is a cross-section along R-R in FIG. 5;

figure 7 is a longitudinal section in the axial direction through the adjustment and resetting device according to the prior art;

FIG. 8 is an exploded view of the adjustment and reset device of FIG. 7;

fig. 9a is a longitudinal section in the axial direction of a ball screw drive according to the prior art, which passes through an adjusting device;

FIG. 9b is an exploded view of the ball screw drive of FIG. 9 a;

fig. 10a is a longitudinal section in the axial direction through the front part of the adjusting device facing the brake disc according to the prior art;

FIG. 10b is an exploded view of the portion of FIG. 10 a;

fig. 11a is a longitudinal section in the axial direction through another part of the adjusting device according to the prior art;

FIG. 11b is an exploded view of the portion of FIG. 11 b;

fig. 12 is a longitudinal section in the axial direction of the novel ball screw drive according to the invention through an adjusting device;

FIG. 13 is an exploded view of the ball screw drive of FIG. 12;

figures 14a and 14b show a disc-shaped element according to the invention;

fig. 15 schematically shows the arrangement of the disc-shaped elements opposite to the internal thread of the ball screw transmission;

figures 16a to 16d schematically illustrate a first manufacturing method according to the invention; and

fig. 17a to 17d schematically show a second manufacturing method according to the invention.

Detailed Description

Figures 1 to 11b show in general all the components of a brake actuating mechanism according to the prior art, as described by way of example in international application WO 2018/015565 a1, the disclosure of which is hereby expressly referred to.

Such a brake actuating mechanism according to the prior art is essentially composed of four functionally cooperating modules, namely an amplification mechanism a, an adjustment device B, a thrust element C and a resetting device D, on which the brake actuating mechanism itself can be mounted as a self-supporting unit by means of a centrally arranged lever 1 and thus in the housing of the brake caliper.

The amplification mechanism a serves to introduce an actuating force from a hydraulic, pneumatic or electromechanical actuator (not shown here) as a clamping force into the brake actuating mechanism and to implement it according to a transmission ratio determined by its design. The lever 2 is pivotably mounted in a rear housing part of a brake caliper (also not shown here) by being rotatably arranged relative to the roller 3, the roller 3 being arranged eccentrically relative to the axis of rotation of the lever 2. A needle bearing or needle bearing cage 4 is provided between the roller 3 and the corresponding surface of the lever 2.

On the opposite side of the roller 3, the lever 2 is pivoted in a corresponding bearing surface of an integral bearing block body 6 by means of a corresponding needle bearing or needle bearing cage 5.

The amplification mechanism a is designed such that, by rotation about the roller 3, the lever 2 performs an eccentric displacement movement relative to the roller 3, which results in a corresponding increase in the actuating force acting on the lever 2, which is then transmitted as a clamping force to the adjusting device B and the thrust element C by means of a translational movement of the bearing block body 6, which bearing block body 6 can be guided linearly in the housing of the brake caliper for this purpose.

The adjusting device B follows the bearing block body 6 directly in the axial direction with respect to the brake disc (not shown here) and comprises a ball screw drive 7, as best shown in fig. 7 to 9B.

The ball screw drive 7 comprises a hollow spindle 8, the hollow spindle 8 being mounted rotatably on the rod 1, in particular by means of a flat or plain bearing bush 9.

The hollow spindle 8 is divided into a threaded section 10 facing away from the brake disc and towards the bearing block body 6 and a cylindrical section 11 facing towards the brake disc.

The threaded section 10 is connected via balls 12 mounted in a double row ball cage 13 to a nut 14 radially surrounding the threaded section 10, as shown in fig. 9 b.

The threaded section 10 has a corresponding outer groove or race 15 and the nut 14 has a corresponding inner groove or race 16, between which the balls 12 arranged in two rows are guided.

The nut 14 forms the drive element of the ball screw transmission 7 and is non-rotatably connected to the bearing housing body 6 by the fact that a projection 17, which is provided at an end face of the nut 14 and extends in the axial direction, engages in a corresponding recess 18 of the bearing housing body 6, as best shown in the sectional view of fig. 4 a.

Due to the kinematics of the ball screw drive 7, this causes a translational movement of the bearing block body 6 and thus of the nut 14, which results in a rotational movement of the hollow spindle 8 on the rod 1 when a clamping force is applied.

The hollow spindle 8, which is the output element of the ball screw drive 7, also forms an input element for the adjusting device B, as will be explained below.

A coupling sleeve 19 is arranged on the hollow spindle 8 in the region of the cylindrical section 11, the coupling sleeve 19 being connected to the hollow spindle 8 in a rotationally fixed manner by means of a press fit.

The coupling sleeve 19 comprises a circumferential flange ring 20 on which a spring 21 is supported, the spring 21 being accommodated on the opposite side in an end recess 22 of the nut 14, so that the spring cannot migrate radially, as shown in fig. 9 a.

The spring 21 is able to keep the pin 17 engaged with the recess 18.

The coupling sleeve 19 is coupled to a radial bearing hub 24 via a first freewheel spring 23. The coupling sleeve 19 and the radial bearing hub 24 radially surround the first freewheel spring, thus forming a first torque clutch M1.

The radial bearing hub 24 is connected in a torque-transmitting connection with a front torque sleeve 26 via a radial bearing 25. The radial bearing hub 24 comprises longitudinal grooves 27 and the front torque sleeve 26 has corresponding longitudinal grooves 28 between which the balls of the radial bearing 25 are mounted such that torque transmission is provided enabling simultaneous axial displacement between these elements.

By forming the second torque clutch M2, the front torque sleeve 26 is connected to the rear torque sleeve 30 via the second freewheel spring 29.

The rear torque sleeve 30 has radial projections 31, the radial projections 31 engaging in corresponding recesses 32 of an adjustment spindle 33. The adjustment spindle 33 completely surrounds the other components of the adjustment device B and has on the outside a thread 34, the thread 34 being in threaded engagement with an internal thread 35 of a pot-shaped thrust piece 36 of the thrust element C. At the front, the thrust member 36 interacts with a brake pad bracket (not shown here) to transmit the clamping force to the brake disc.

As shown in the cross-sectional view of fig. 6a, the rear torque sleeve 30 is supported on the bearing housing body 6 by a low friction radial bearing 37 with an intermediate ring 38 inserted therein. The bearing housing body 6 is in turn in direct contact with the adjustment spindle 33 via a bearing surface 39 (see fig. 2b), whereby a radial circumferential axial projection 40 (see fig. 2a) of the adjustment spindle 33 engages in an annular recess 41 of the bearing housing body 6. This ensures that the main force flow of the clamping force from the bearing housing body 6 directly enters the adjusting spindle 33 via the threaded

engagement

34, 35 on the thrust piece 36, while the rear torque sleeve 30 and thus the adjusting device B as a whole remain disengaged from the clamping force in the axial direction as far as possible due to the low-friction radial bearing 37.

On the opposite side of the radial bearing 37, a planar plain bearing ring 42 is arranged on the front torque sleeve 26, the planar bearing ring 42 being guided opposite a retaining ring 43.

The spring 44 of the reset device D is in contact with the retaining ring 43. The return spring 44, which is designed as a helical spring, in turn rests on an abutment housing 45, which abutment housing 45 is fastened to the end of the rod 1 facing the brake disc by means of a fastening nut 46.

The abutment housing 45 is clamped between the abutment ring 47 and the fastening nut 46.

The hollow spindle 8 is in turn supported on the abutment ring 47 in rotatable support via a retaining ring 48 and an axial bearing 49 in order to absorb axial forces acting on the hollow spindle 8.

By forming the third torque clutch M3, the abutment ring 47 is coupled to the radial bearing hub 24 via the third freewheel spring 50, the radial bearing hub 24 radially outwardly surrounding these components.

As can be seen from fig. 1, the entire brake actuating mechanism is held on the brake disk side by the fastening nut 46 and on the side facing away from the brake disk by means of the fastening ring 51 on the lever 1, wherein the amplification mechanism a, the adjusting device B, the thrust element C and the reset device D are functionally arranged in a cooperating manner, the hollow adjusting spindle 33 completely receiving the remaining components of the adjusting device B and the reset device D. The brake actuating mechanism can be mounted and fixed in the caliper housing as a unit by means of the lever 1. For sealing the housing of the brake caliper, a sealing sleeve 52 is provided between the thrust piece 36 and the inner wall of the brake caliper housing, the sealing sleeve 52 rolling axially with the translational movement of the thrust element C.

During brake actuation, the first freewheel spring 23 of the first torque clutch M1 locks the coupling sleeve 19 with the radial bearing hub 24 when a translational movement of the bearing housing body 6 causes the hollow main shaft 8 to rotate by means of the ball screw transmission 7. The rotation is then correspondingly transmitted to the front torque sleeve 26 via the radial bearing 25.

The correspondingly large-sized second freewheel spring 29 of the second torque clutch M2 slips according to the variation of the torque thus defined during the actuation stroke, thereby limiting the torque relative to the rear torque sleeve 30, which rear torque sleeve 30 is coupled in a rotationally fixed manner to the adjusting spindle 33.

Rotation of the front torque sleeve 30 causes the return spring 44 to wrap around the sliding bearing ring 42 and retaining ring 43, i.e., to twist upon itself and to be compressed, because the frictional engagement between the return spring 44 and retaining ring 43 is large enough to prevent slippage between the end of the return spring 44 and the retaining ring 43. The degree of winding or compression is limited by the front torque sleeve 30 and is determined by the friction in the sliding bearing ring 42 between the retaining ring 43 and the front torque sleeve 26.

During brake release, i.e. when the clamping force is no longer transmitted, the spring 21 causes the nut 14 to follow the rearward movement of the bearing housing body 6. This causes the hollow spindle 8 to rotate back to its original position.

In addition, the return spring 44 is rewound or stretched, which causes the front torque sleeve 26 to rotate in the opposite direction by means of the retaining ring 43 and the sliding bearing ring 42. In this rotational direction, a correspondingly large second freewheel spring 29 couples the front torque sleeve 26 with the rear torque sleeve 30.

However, this degree of rotation is limited by the fact that: the third freewheel spring 50 of the third torque clutch M3 brakes the rotation of the radial bearing hub 24, i.e. limits the rotation range of the radial bearing hub 24, so to speak, depending on the size to be adjusted. This limited rotation or rotations are then transmitted via the radial bearing 25 to the front torque sleeve 26 and thus to the rear torque sleeve 30, since in this direction of rotation the two

torque sleeves

26 and 30 are coupled via the second freewheel spring 29. Once the third freewheel spring 50 locks, the return spring 44 stops winding or extending downward. The third freewheel spring 50 is coupled by a second freewheel spring 29 with a quasi-defined resistance force, which determines the size to be adjusted for each braking stroke. Finally, this rotation, which is subject to the resistance force from the third freewheel spring 50, is transmitted from the rear torque sleeve 30 to the adjustment spindle 33 via the anti-torque coupling, which results in a corresponding adjustment of the play due to the anti-rotational guidance of the thrust piece 36 and the threaded

joints

34, 35, i.e. when the brake actuating mechanism is reset, the thrust piece 36 moves forward relative to the adjustment spindle 33 towards the brake disc according to the rotation performed under the action of the thrust spindle 33, while these two elements actually move rearward relative to the caliper housing.

Quantitatively, the clearance (a measure) is affected by all tolerances or clearances spread over the components of the brake actuation mechanism that are in the force flow within the adjustment range during the actuation stroke, i.e., when the lever 2 pushes the bearing block body 6 forward towards the brake disc. This includes a very small angular clearance between the bearing block body 6 and the nut 14, which generally corresponds to the tolerances intended for assembly, the clearance between the nut 14, the balls 12 and the hollow spindle 8, the rotational mobility of the first freewheel spring 23 between the coupling sleeve 19 connected in a rotationally fixed manner to the hollow spindle 8 and a radial bearing hub 24 which can then be driven by means of the first freewheel spring 23, the clearance between the radial bearing hub 24, the balls of the radial bearing 25 and the front torque sleeve 26, the rotational mobility of the second freewheel spring 29 between the front torque sleeve 26 and the rear torque sleeve 30, the angular clearance between the radial projections 31 of the rear torque sleeve 30 and the recesses 32 of the adjustment spindle 33 and the clearance in the thread between the adjustment spindle 33 and the thrust piece 36. By specifically dimensioning the above-mentioned components and thereby determining the respective clearances, tolerances and rotational mobility, the required clearance (a-measure) can be determined from a design point of view and then has to be set by the brake actuating mechanism according to the invention.

Fig. 12 to 15 show a novel ball screw transmission 7' according to the invention, which can be used in a brake actuating mechanism of the type described above. The manner of operation is substantially the same with respect to the adjustment. Like components are labeled with like reference numerals.

The ball screw drive 7' also has a hollow spindle 8, which hollow spindle 8 is divided into a threaded section 10 facing away from the brake disk and facing the bearing block body 6 and a cylindrical section 11 facing the brake disk.

The threaded section 10 is connected via balls 12 mounted in a double row ball cage 13 to a nut 14 radially surrounding the threaded section 10.

The threaded section 10 has a corresponding outer ring 15 and the nut 14 has a corresponding inner ring 16, between which the double row of balls 12 is guided.

The nut 14 forms, as in the prior art, a drive element of the ball screw transmission 7' and is non-rotatably connected to the bearing block body 6 by means of a projection 17 provided in the front of the nut 14 and extending in the axial direction engaging in a corresponding recess 18 of the bearing block body 6. Likewise, the hollow spindle 8, which is the output element of the ball screw drive 7', also forms the input element of the adjusting device B.

The coupling sleeve 19 comprises a circumferential flange ring 20, the spring 21 being supported on a bearing ring 55, which bearing ring 55 is mounted on the flange ring 20 via an axial bearing 56. The spring 21 is accommodated on the opposite side in an end recess 22 of the nut 14, so that the spring cannot migrate radially.

According to the invention, the circumferential travel of the balls 12 is limited by the fact that the front ends, and therefore the front end openings, of the outer ring 15 of the spindle 8 and the inner ring 16 of the nut 14 are limited by stops designed as differently shaped disc-shaped

elements

60 and 61.

As fig. 15 schematically shows the restriction with respect to the nut 14, the disc-shaped element 60 has a profile with a convex surface 62, which convex surface 62 is form-fittingly engaged in the shape of the inner ring 16 and has at least a clearance such that the disc-shaped element 60 is rotatably mounted to some extent. Thus, the disc element 60 may also move to some extent in the axial direction.

Similarly, the disc-shaped element 61 interacting with the spindle 8 has a profile with a projection 63 (fig. 14b) into which a corresponding profile of the outer ring 15 fits.

The disc-shaped element 60 acts in the clamping direction, whereas the disc-shaped element 61 acts in the opposite direction. During the adjusting or resetting movement, the balls 12 of the ball screw drive 7 'can assume different axial positions before the ball screw drive 7' rotates. However, each time the adjustment device is fully actuated, the ball 12 comes into contact with the disc-shaped

element

60 or 61, depending on the direction of rotation. Thus, according to the invention, the disc-shaped

elements

60 and 61, which act as stops, determine the axial position of the balls 12 and their orientation perpendicular to the spindle axis. If the balls 12 are for any reason not in the correct axial position at the beginning of the adjusting movement, they only travel or roll for a very short time relative to the disc-shaped

element

60 or 61.

In other words, if the balls 12 are in contact with the respective disc-shaped

element

60 or 61, the extent of the circumferential travel of the balls 12 and therefore of the possible rotation of the hollow spindle 8 and therefore of the translation of the nut 14 is limited.

The disc-shaped

elements

60 and 61 may themselves be in contact with an abutment arranged to narrow at the respective end openings of the cross-section of the inner ring 15 and the outer ring 16.

This can be seen as an example of the nut 14 in fig. 16d and an example of the spindle 8 in fig. 17d, which applies to the method according to the invention.

Fig. 16a shows the nut base 14 before grinding the inner ring 16. One end of the nut base 14 has a tapered collar 64. By grinding the grooves of the inner rings 15 extending into the collar 64, each inner ring 15 forms a protruding lug 65, as can be seen in particular in fig. 16 c. In a subsequent step of the method, the nut 14 is placed under pressure between two punches or abutments S to plastically deform the lugs 65 and, consequently, each inner ring 16 narrows accordingly at its axially open end. These bead-like constrictions form abutments 66, as shown in fig. 16d, against which the disc-shaped element 60 can rest.

The abutment for the disc-shaped element 61 of the spindle 8 is formed in a similar manner, which is shown sequentially by fig. 17a to 17 d.

The main shaft base body 8 is provided with a collar 67 with a conical opening at the front end of the threaded section 10. By grinding the outer ring 15, then forming in each ring axially projecting lugs 68 from the collar 67, the lugs 68 can then be plastically deformed by means of a punch S so that they narrow the cross section of the outer ring 15, thus forming a beaded abutment 69 against which the disc-shaped element 61 can then rest.

Claims

1. A brake actuation mechanism for a disc brake, the brake actuation mechanism comprising:

-an amplification mechanism (a) for introducing a clamping force for a braking operation;

-a thrust element (C) for transmitting said clamping force to the brake disc;

-the amplification mechanism (a) and the thrust element (C) cooperate so that the thrust element (C) performs a translational movement in the direction of the brake disc due to a displacement movement of the amplification mechanism (a); and

-an adjustment device (B) for compensating the wear of the lining,

wherein an input element of the adjusting device (B), which is designed as a spindle (8) of a ball screw drive (7 '), can be set into rotation as a result of the translatory movement, wherein the balls (12) are guided in a plurality of parallel outer rings (15) of a threaded portion (10) of the spindle (8) and in a plurality of parallel inner rings (16) of a nut (14) of the ball screw drive (7'),

wherein the outer ring (15) and the inner ring (16) are open on both sides of the ball screw drive (7') and are each provided with a stop (60, 61) which limits the circumferential travel of the balls (12),

it is characterized in that the preparation method is characterized in that,

the stop (60, 61) is formed by a disc-shaped element.

2. Brake actuation mechanism according to claim 1, wherein the disc-shaped elements (60, 61) are supported freely movable in axial direction.

3. Brake actuation mechanism according to claim 1 or 2, wherein a first disc-shaped element (61) is connected to the spindle (8) and spaced apart from the nut (14).

4. Brake actuation mechanism according to claim 3, wherein the first disc element (61) is shaped in conformity with the contour of the outer ring (15) of the threaded portion (10) and is guided in the outer ring (15).

5. Brake actuation mechanism according to claim 3 or 4, in which the outer rings (15) each have an abutment (69) at their stop-side ends, the first disc-shaped elements (61) abutting against the abutments (69).

6. The brake actuation mechanism of claim 5, wherein the abutment (69) is formed by plastic deformation of the material of the spindle (8).

7. Brake actuation mechanism according to one of claims 1 to 6, in which a second disc-shaped element (60) is connected to the nut (14) and spaced apart from the spindle (8).

8. Brake actuation mechanism according to claim 7, wherein the second disc-shaped element (60) is formed in a shape conforming to the contour of the inner ring (16) of the nut (14) and is guided in the inner ring (16).

9. Brake actuation mechanism according to claim 7 or 8, wherein the inner rings (16) each have an abutment (66) at their stop-side ends, the second disc-shaped element (60) abutting against the abutment (66).

10. The brake actuation mechanism of claim 9, wherein the abutment (66) is formed by plastic deformation of the material of the nut (14).

11. Brake actuation mechanism according to one of claims 1 to 10, wherein the number and/or pitch angle of the outer rings of the spindle (8) and/or the number and/or pitch angle of the inner rings of the nut (14) differ.

12. Brake actuation mechanism according to claim 11, wherein the outer ring (15) of the spindle (8) and/or the inner ring (16) of the nut (14) have a varying pitch.

13. Brake actuation mechanism according to claim 11 or 12, wherein the outer ring (15) of the spindle (8) and/or the inner ring (16) of the nut (14) are designed such that a first adjustment is effected by the adjustment device (B) at low rotational speeds of the spindle (8) and a further adjustment exceeding the first adjustment is effected at higher rotational speeds of the spindle (8).

14. Brake actuation mechanism according to one of claims 1 to 13, in which the input element of the regulating device (B) is directly or indirectly engaged with a torque clutch (M1).

15. Brake actuation mechanism according to one of claims 1 to 14, wherein the amplification mechanism (A), the thrust element (C) and the adjustment device (B) can be mounted in a functionally fitting manner in a brake caliper by means of a lever (1), the lever (1) being mounted in a housing of the brake caliper of the disc brake immovably and non-rotatably in the axial direction,

wherein the input element of the adjusting device (B) is designed as a hollow spindle (8) of a ball screw drive (7') which is rotatably mounted on the lever (1).

16. A disc brake comprising a brake actuation mechanism according to any one of claims 1 to 15.

17. The disc brake of claim 16, in which the brake actuation mechanism according to any one of claims 1 to 15 is mountable as a self-supporting unit by means of a lever (1) in a housing of a caliper of the disc brake.

18. A method of manufacturing a spindle (8) for a ball screw drive (7; 7'), in particular for a brake actuator, comprising the steps of:

-forming the main shaft base body (8) such that at least one end face a conical collar (67) is formed which tapers in the axial direction,

-forming an outer ring (15) at least sectionally on an outer surface of the spindle base body (8), the outer ring (15) extending into the collar (67), wherein each outer ring is formed with lugs (68), and

-pressing the front end of the spindle base body (8) against an abutment (S) so that the lugs (68) constrain the outer ring (15) under plastic deformation.

19. A method of manufacturing a nut (14) for a ball screw drive (7; 7'), in particular for a brake actuator, comprising the steps of:

-forming a nut base body (14) with a through hole such that at least one end face of the through hole a conical collar (64) is formed which tapers in axial direction,

-forming an inner ring (16) at least sectionally on an inner surface of the through hole, the inner ring (16) extending into the collar (64), wherein each inner ring is formed with lugs (65), and

-pressing the front end of the nut base (14) against an abutment (S) so that the lugs (64) constrain the inner ring (16) under plastic deformation.