Drum brake, brake system and vehicle

Abstract

The invention relates to a drum brake (1) having at least one brake shoe (4), a deformation sensor (10) and a carrier (2a), wherein the carrier (2a) has a support bearing (3a) for the at least one brake shoe (4), wherein the deformation sensor (10) is designed to determine a deformation of the carrier (2a), wherein the support bearing (3a) is formed separately from the carrier (2a). The support bearing (3a) is connected to the carrier (2a) in a force-transmitting manner by means of an interlocking connection. The invention also relates to a brake system (20) having at least one such drum brake (1), and to a vehicle (30) having such a brake system (20) or at least one such drum brake (1).

Description

[0001] Description

[0002] Drum brake, braking system and vehicle

[0003] Technical area

[0004] The invention relates to a drum brake according to the preamble of claim 1. Furthermore, the invention relates to a braking system having at least one such drum brake and to a vehicle having such a braking system or at least one such drum brake.

[0005] State of the art

[0006] The documents US 4 995 480 A, US 5 979 613 A, US 2020 018 0575 A1 , US 1 915 857 A and US 5 913 390 A disclose drum brakes.

[0007] The document DE 10 2013 224 922 A1 discloses a drum brake with an electromechanical actuator and a brake shoe, wherein a sensor is arranged in the force flow between the actuator and the brake shoe, with which the braking force can be determined.

[0008] The document DE 10 2017 217413 A1 discloses a drum brake with a brake shoe and a support bearing, wherein a force sensor on the support bearing enables a measurement of a support force generated by the brake shoe in the support bearing.

[0009] A particular disadvantage of the prior art devices is that when measuring braking force using the prior art devices, a pronounced hysteresis of the measurement signal occurs. Description of the invention, problem, solution, advantages

[0010] The object of the present invention is to provide an alternative drum brake, which is particularly characterized by the fact that a low hysteresis of the measurement signal occurs when measuring braking force with this drum brake. A further object is to provide a braking system with such a drum brake. A further object is to provide a vehicle with such a braking system or with such a drum brake.

[0011] The first object is achieved by a drum brake having the features of claim 1.

[0012] One embodiment of the invention relates to a drum brake with at least one brake shoe, a deformation sensor, and a carrier. The carrier has a support bearing for the at least one brake shoe. The deformation sensor is designed to detect a deformation of the carrier. The support bearing is formed separately from the carrier. The support bearing is connected to the carrier in a force-transmitting manner by means of a positive connection.

[0013] This makes it possible to determine the braking force or braking torque of the drum brake during its actuation in a simple, cost-effective and reliable manner, since the supporting force generated during the braking process, introduced and transmitted by the at least one brake shoe to the supporting bearing, is transferred from the supporting bearing to the carrier, causing a deformation of the carrier that depends on the braking force or braking torque of the drum brake. This occurs because the at least one brake shoe is able to support itself on the supporting bearing during a braking process of the drum brake, whereby the supporting force thereby transmitted to the carrier leads to a deformation of the carrier. In other words, it is preferred if the at least one brake shoe is arranged so that it is supported or can be supported on the supporting bearing. In addition, hysteresis is reliably reduced by the positive connection.

[0014] In particular, it is possible to determine the braking force and / or braking torque based on the determined deformation of the carrier.

[0015] It is advantageous if the support is made of a metal. In other words, in this case the support is made of metal. Alternatively, it is conceivable for the support to be made at least predominantly of metal. This contributes to the longevity and reliability of the support. Preferably, the material or metal from which the support is made is a ductile material, a ductile metal, or a ductile steel. In other words, it is a material, a metal, or a steel that is capable of elastic deformation under load. It is particularly preferred if it is a ferritic metal or a ferritic steel.

[0016] It is also advantageous if the carrier is dimensioned such that the carrier undergoes only elastic, in particular linear-elastic, deformation during operation of the drum brake, in particular during a braking process. In other words, the carrier is dimensioned or designed such that the carrier is only elastically deformable by the forces occurring during operation of the drum brake. In this way, failure of the carrier or sustained, i.e., permanent, deformation of the carrier compared to its original shape is reliably avoided. Furthermore, this ensures that braking force or braking torque measurements performed using the deformation sensor have a comparable accuracy.It is particularly expedient if the maximum mechanical stress occurring in the support and / or a deformation element, which may be part of a preferred embodiment, during a braking operation of the drum brake corresponds to a maximum of half, one-third, one-quarter, or one-fifth of the upper yield point of the material of the support and / or the deformation element. This is achieved by appropriately dimensioning the support, the target deformation range of the support, and / or the deformation element. This largely prevents hysteresis of the shape of the support and / or the deformation element due to the deformation occurring during the braking operation, which contributes to measurement accuracy.

[0017] Furthermore, it is advantageous if the deformation sensor is a capacitive, inductive, piezoelectric, or resistive sensor. Alternatively, it is also advantageous if the deformation sensor is a sensor with one or more strain gauges or if it is a surface acoustic wave (SAW) sensor.

[0018] Furthermore, it is advantageous if the support bearing and / or the carrier is / are designed separately, in particular completely separately, from the deformation sensor. In other words, the support bearing and / or the carrier is / are not part of the deformation sensor. Alternatively, the deformation sensor is designed to be carrier-free and / or support-bearing-free. Furthermore, it is preferred if the support bearing and / or the carrier is arranged and / or designed at a distance from the deformation sensor. Furthermore, it is preferred if the sensor does not have the support bearing and / or the carrier. Furthermore, it is preferred if the carrier and / or the support bearing are designed to be free of sensor functions, which means in particular that the carrier and / or the support bearing are not part of the sensor.

[0019] It is particularly advantageous if the drum brake comprises two brake shoes arranged in such a way that one or both of the brake shoes can be supported on the support bearing during a braking operation. This option is available for all embodiments mentioned above and below, as long as the type of drum brake allows it.

[0020] Furthermore, it is advantageous if the at least one brake shoe is or can be coupled to the support bearing in a direct and / or indirect force-transmitting manner. Thus, a force from the brake shoe, the so-called support force, can be transmitted to the support bearing and from the support bearing to the carrier. Preferably, each of the brake shoes comprises a brake pad and / or each of the brake shoes is mounted in a floating manner.

[0021] Furthermore, it is expedient if the carrier forms a force path or the only force path from the at least one brake shoe and / or the support bearing to a periphery of the drum brake, for example, a wheel carrier or a steering knuckle, to which the carrier is preferably connected or fastened. In other words, it is preferred if the supporting force of the at least one brake shoe can be transmitted predominantly or solely, i.e., exclusively, from the support bearing to the periphery via the force path formed by the carrier.

[0022] Generally, it is preferred if the drum brake is a simplex brake, a duplex brake, a duo-duplex brake, a servo brake, or a duo-servo brake. This makes it possible to provide suitable drum brake types for different applications or vehicles.

[0023] In principle, the drum brake according to the invention is a drum brake for a motor vehicle. Irrespective of this, it is in principle or additionally conceivable for the drum brake according to the invention to be a drum brake that can be actuated hydraulically and / or mechanically and / or electrically. Mechanical actuation can be achieved, for example, by means of cables of a parking brake, a so-called handbrake. Electrical actuation can be achieved, for example, by means of an electric actuator. In such a case, such an electric actuator is preferably integrated into the drum brake according to the invention. The sensor preferably serves to operate, in particular to regulate and / or control, the actuator and is thus preferably capable of providing the requested or necessary braking torque by means of the drum brake.

[0024] Furthermore, it is particularly preferred if the braking force and / or braking torque of the drum brake can be determined from the deformation of the carrier and / or a deformation element of the carrier determined by the deformation sensor. For this purpose, it is particularly preferred if the measurement signal of the deformation sensor can be evaluated by an evaluation unit in such a way that a braking force signal and / or a braking torque signal can be generated or is generated by the evaluation unit. Such an evaluation unit is preferably integrated into a control unit. The evaluation unit and / or the control unit are preferably provided with the drum brake.

[0025] Furthermore, it is expedient if the carrier can be connected or is connected to a peripheral component in a force-transmitting manner. In this way, the braking force or braking torque of the drum brake can be transmitted to the carrier by means of the support bearing and from the carrier to the peripheral component, or can be supported on the peripheral component. The peripheral component is preferably part of a vehicle or motor vehicle, for example, a steering knuckle or a wheel carrier.

[0026] One of the previous or a further exemplary embodiments is preferably characterized in that the carrier can be connected to a steering knuckle or is formed integrally with a steering knuckle. Alternatively, it is conceivable that the carrier can be connected to a wheel carrier or is formed integrally with a wheel carrier. In other words, the steering knuckle or the wheel carrier forms the periphery. The connection of the carrier to the steering knuckle or the wheel carrier is, in particular, a fastening. In this way, any supporting forces that occur during a braking process can be supported. The connection is preferably a screw connection. The one-piece design eliminates additional assembly steps and additional manufacturing effort.

[0027] In general, it is advantageous if the support bearing is subjected to a shear force by at least one brake shoe during the braking process of the drum brake. The force introduction point between the at least one brake shoe and the support bearing is advantageously located on the lateral outer contour of the support bearing. Furthermore, it is advantageous if the support bearing is directly connected or attached to the carrier. This eliminates the need for additional components that would be necessary with an indirect connection or attachment, further reducing costs.

[0028] A further preferred embodiment is characterized in that the carrier has at least one material weakening. Material weakening makes it possible to achieve a targeted deformation of the carrier, for example, a linear-elastic deformation of the carrier, under the action of a supporting force caused by the at least one brake shoe of the drum brake during a braking operation of the drum brake. Furthermore, the material weakening is preferably dimensioned such that the deformation of the carrier during a braking operation of the drum brake is within the measuring range of the deformation sensor. This allows the use of inexpensive deformation sensors.

[0029] A further preferred embodiment is characterized in that the at least one material weakening is designed as a recess.

[0030] It is also preferable for the recess to be designed such that it extends through the carrier. Alternatively, it is conceivable for the recess to be designed such that the thickness or strength of the carrier is reduced. In other words, in this case, the recess does not extend through the carrier.

[0031] Furthermore, it is particularly advantageous if the deformation sensor and / or the deformation element is arranged in a region of the carrier which remains as cool as possible during operation of the drum brake, since the distance to the heat source is as great as possible.

[0032] One of the previous embodiments or a further preferred embodiment is characterized in that the carrier is arranged such that a supporting force can be transmitted from the at least one brake shoe to the carrier by means of the support bearing. In other words, the support bearing preferably forms a force introduction point for the at least one brake shoe or a force introduction point for each brake shoe. If the carrier is connected to a steering knuckle or a wheel carrier or fastened to one of the two, the carrier transmits the supporting force to the wheel carrier or the steering knuckle. In other words, the carrier forms a force path from the at least one brake shoe via the support bearing to the wheel carrier or the steering knuckle.

[0033] A preferred embodiment is characterized in that the support bearing is attached to the carrier, in particular by means of a screw connection. This divides the tasks between the attachment and the positive connection. While the attachment merely ensures that the support bearing is attached to the carrier, the positive connection between the support bearing and the carrier ensures force transmission with as little hysteresis as possible.

[0034] A further preferred embodiment is characterized in that the support is connectable to a steering knuckle or is formed integrally with a steering knuckle. Such a connection is preferably implemented by means of a screw connection. While a one-piece design complicates repair or replacement, it simplifies series production by eliminating an assembly step and reduces unit costs.

[0035] A further preferred embodiment is characterized in that the positive connection is formed by means of at least one recess in the carrier and at least one projection of the support bearing. The positive connection is preferably designed such that a supporting force of a brake shoe, which is transferable to the support bearing, can be transmitted to the carrier in a force-transmitting manner by means of the positive connection.

[0036] A further preferred embodiment is characterized in that the positive connection is formed by means of at least one recess in the support bearing and at least one projection of the carrier. The positive connection is preferably designed such that a supporting force of a brake shoe, which is transferable to the support bearing, can be transmitted to the carrier in a force-transmitting manner by means of the positive connection.

[0037] It is also preferable if the carrier comprises at least one projection and one recess, while the support bearing comprises a recess matching the projection of the carrier and a projection matching the recess of the carrier.

[0038] A further preferred embodiment is characterized in that at least one recess and at least one projection, which together form the positive connection, are congruent with one another and / or form a fit. The fit is preferably a clearance or transition fit, which enables the joining of the carrier to the support bearing. Furthermore, the fit ensures the most precise positioning of the support bearing on the carrier during assembly and operation.

[0039] A further preferred embodiment is characterized in that the at least one recess and the at least one projection, i.e., the positive connection, are formed in a square, rectangular, trapezoidal, or dovetail-shaped plane. This plane preferably runs, in particular partially, parallel to or, in particular partially, along a parting plane that separates the support bearing from the carrier. Additionally or alternatively, the plane runs along the extension direction of the screws of the screw connection.

[0040] In principle, the level is a first level or the first level if it is an embodiment that refers to another level.

[0041] A further preferred embodiment is characterized in that the at least one recess and the at least one projection are square, rectangular, or trapezoidal in a further plane extending perpendicular to the first plane. Alternatively or additionally, the further plane, which can also generally be referred to as the second plane, extends perpendicular to the direction of extension of the screws of the screw connection.

[0042] A further preferred embodiment is characterized in that the at least one recess and the at least one projection are formed in a further plane extending perpendicular to the first plane such that their contact with each other is V-shaped. Alternatively or additionally, the further plane, which can also generally be referred to as the second plane, extends perpendicular to the direction of extension of the screws of the screw connection.

[0043] A further preferred embodiment is characterized in that the carrier has a deformation element which is connected to the carrier in a force-transmitting manner, wherein the deformation of the deformation element can be determined or measured by the deformation sensor, whereby the deformation of the carrier can be determined or measured indirectly.

[0044] A further preferred embodiment is characterized in that the deformation element is arranged on a side of the support facing away from the support bearing and / or that the deformation element is connected to the support in a force-transmitting manner by means of screws, rivets, or bolts. This arrangement largely protects the deformation element from the heat generated by the drum brake.

[0045] The second object is achieved by providing a braking system with at least one drum brake according to the invention. It is preferred if the braking system comprises one, two, three, four, or more than four drum brakes according to the invention.

[0046] The third object is achieved by providing a vehicle with a braking system according to the invention or at least one drum brake according to the invention. Preferably, this is a motor vehicle that, in particular, includes an electric drive.

[0047] Advantageous further developments of the present invention are described in the subclaims and in the following description of the figures.

[0048] Short description of the drawings

[0049] The invention is explained in detail below using exemplary embodiments with reference to the drawings. In the drawings:

[0050] Fig. 1 a vehicle,

[0051] Fig. 2 a drum brake,

[0052] Fig. 3 a carrier of the drum brake,

[0053] Fig. 4a-d different shaped, positive-locking connections between support bearing and carrier in a first view, and

[0054] Fig. 5a-g of different shaped, positive-locking connections between support bearing and beam in a further view.

[0055] Preferred embodiment of the invention

[0056] Figure 1 shows a vehicle 30 according to the invention, which is designed as a motor vehicle with two axles and an electric drive. The vehicle 30 comprises a braking system 20 according to the invention, which has four drum brakes 1 according to the invention. Of the four drum brakes 1 according to the invention, two drum brakes 1 are assigned to each axle of the vehicle 30. The drum brakes 1 are designed both as service brakes and as parking brakes and can therefore be operated as such. The braking system 20 further comprises a control unit 21, by means of which the drum brakes 1 can be operated and braking signals, such as braking force signals or braking torque signals, can be evaluated. In addition, the control unit 21 is designed such that it can operate the braking system 20 as a driver assistance system. For this purpose, it is conceivable that further signals from further sensors of the vehicle 30 are processed in the control unit 21.

[0057] Figure 2 shows a drum brake 1 according to the invention from Figure 1 in a simplified representation. The drum brake 1 comprises a carrier 2a, which is connected to a steering knuckle 11 via a carrier connection 2b. The two brake shoes 4 each have a brake pad 5. The brake shoes 4 are movable in the radial direction 8a against a brake drum 6 rotatable in the direction of rotation 8b by means of an actuator 7, which is designed as an electric actuator, so that when the brake pads 5 come into contact with the rotating brake drum 6, the brake drum is decelerated. The actuator can alternatively be designed as a hydraulic actuator. The friction between the brake pads 5 and the brake drum 6 creates a supporting force, which is guided by the brake shoes 4 via a support bearing 3a into the carrier 2a and transmitted to the steering knuckle 11.The steering knuckle 11 can be connected to a periphery that can absorb the resulting support force.

[0058] Figure 3 shows the carrier 2a of the drum brake from Figure 2. The carrier 2a is made of metal and has weight-reducing recesses. The separately formed support bearing 3a can also be seen. The support bearing 3a is also made of metal, but has greater rigidity than the carrier 2a due to the choice of material and its shape. At a point on the carrier 2a facing away from the support bearing 3a, a deformation element 9 is connected to the carrier 2a in a force-transmitting manner. As a result, a deformation of the carrier 2a, caused by a braking operation of the drum brake, leads to a deformation of the deformation element 9. This deformation of the deformation element 9 is measured by a deformation sensor 10. This measurement can be used to determine the deformation of the carrier 2a and thus the braking force or braking torque of the drum brake. Fig.Figures 4a-d show variously shaped, positive-locking connections between the support bearing and the carrier of the drum brake in a first view. The illustrations in Figures 4a-d, each of which corresponds to an embodiment, correspond to a sectional view in the XY plane running along the extension direction of a screw connection between the support bearing 3a and the carrier 2a. The screw connection represents a fastening 3b, which is indicated in Figures 4a-d.

[0059] Figure 4a shows that the support bearing 3a has a trapezoidal recess into which a projection of the carrier 2a engages congruently. This creates a positive connection between the carrier 2a and the support bearing 3a.

[0060] In Figure 4b it can be seen that the support bearing 3a has a trapezoidal projection which engages in a trapezoidal recess of the carrier 2a and thus forms a positive connection between the carrier 2a and the support bearing 3a.

[0061] In Figure 4c it can be seen that the support bearing 3a comprises two trapezoidal projections, each of which engages congruently in a trapezoidal recess of the carrier 2a, thus forming a positive connection between the carrier 2a and the support bearing 3a.

[0062] In Figure 4d it can be seen that the positive connection between the support bearing 3a and the carrier 2a is realized by a dovetail guide.

[0063] Figures 5a-g show a further view of variously shaped, positive-locking connections between the support bearing and the drum brake support. Some of these are the variously shaped, positive-locking connections shown in Figures 4a-d. Each view shows a sectional view in the XZ plane, which runs perpendicular to the XY plane of Figures 4a-d and intersects the positive-locking connection between the support bearing 2a and the drum brake support 3a. The view in the Y direction is shown in each case.

[0064] Figure 5a shows a rectangular positive connection, while Figure 5b discloses a trapezoidal positive connection between the carrier 2a and the support bearing 3a. These two embodiments preferably refer to the trapezoidal positive connections of the embodiments of Figures 4a and 4b.

[0065] Figures 5c and 5d reveal opposing V-shaped positive-locking connections between the carrier 2a and the support bearing 3a. These two embodiments preferably refer to the trapezoidal positive-locking connections of the embodiments of Figures 4a and 4b.

[0066] Figures 5e, 5f and 5g disclose specific embodiments which preferably relate to the embodiment of Figure 4d with the dovetail guide.

[0067] The different features of the individual embodiments can also be combined with each other.

[0068] The embodiments of Figures 1 to 5g are in particular not restrictive in nature and serve to clarify the inventive concept.

[0069] Reference symbol list

[0070] I Drum brake

[0071] 2a carrier

[0072] 2b Beam connection

[0073] 3a Support bearing

[0074] 3b Fastening

[0075] 4 brake shoes

[0076] 5 brake pad

[0077] 6 brake drum

[0078] 7 Actuator

[0079] 8a Radial direction

[0080] 8b Direction of rotation

[0081] 9 Deformation element

[0082] 10 Deformation sensor

[0083] II Steering knuckle

[0084] 20 Braking system

[0085] 21 Control unit

[0086] 30 vehicles

Claims

Patent claims 1 . Drum brake (1 ) with at least one brake shoe (4), a deformation sensor (10) and a carrier (2a), wherein the carrier (2a) has a support bearing (3a) for the at least one brake shoe (4), wherein the deformation sensor (10) is designed to determine a deformation of the carrier (2a), wherein the support bearing (3a) is designed separately from the carrier (2a), characterized in that the support bearing (3a) is connected to the carrier (2a) in a force-transmitting manner by means of a positive connection.

2. Drum brake (1) according to claim 1, characterized in that the support bearing (3a) is fastened to the carrier (2a), in particular by means of a screw connection (3b).

3. Drum brake (1) according to one of the preceding claims, characterized in that the carrier (2a) can be connected to a steering knuckle (11) or is formed in one piece with a steering knuckle (11).

4. Drum brake (1) according to one of the preceding claims, characterized in that the positive connection is formed by means of at least one recess of the carrier (2a) and at least one projection of the support bearing (3a).

5. Drum brake (1) according to one of the preceding claims, characterized in that the positive connection is formed by means of at least one recess of the support bearing (3) and at least one projection of the carrier (9).

6. Drum brake (1) according to one of claims 4 or 5, characterized in that at least one recess and at least one projection, which together form the positive connection, are congruent to one another and / or form a fit.

7. Drum brake (1) according to one of the preceding claims, characterized in that the at least one recess and the at least one projection in a plane are square-shaped, rectangular-shaped, trapezoidal-shaped or in the form of a dovetail guide.

8. Drum brake (1) according to claim 7, characterized in that the at least one recess and the at least one projection in a further plane extending at right angles to the first plane are square-shaped, rectangular-shaped or trapezoidal.

9. Drum brake (1) according to claim 7, characterized in that the at least one recess and the at least one projection in a further plane extending at right angles to the first plane are formed such that their contact with one another is V-shaped.

10. Drum brake (1) according to one of the preceding claims, characterized in that the carrier (2a) has a deformation element (9) which is connected to the carrier (2a) in a force-transmitting manner, wherein the deformation of the deformation element (9) can be determined or measured by the deformation sensor (10), whereby the deformation of the carrier (2a) can be determined or measured indirectly.

11. Drum brake (1) according to claim 10, characterized in that the deformation element (9) is arranged on a side of the carrier (2a) facing away from the support bearing (3a) and / or that the deformation element (9) is connected to the carrier (2a) in a force-transmitting manner by means of screws, rivets or bolts.

12. Brake system (20) with at least one drum brake (1) according to one of the preceding claims.

13. Vehicle (30) with a braking system (20) according to claim 12 or at least one drum brake (1) according to one of claims 1 to 11.

Images