WO2017182490A1 - Braking device for a rail vehicle and method for determining a braking torque of a braking device - Google Patents

Abstract

The invention relates to a braking device for a rail vehicle comprising a brake caliper unit (10) which can be secured to a chassis of the rail vehicle by means of a console (3) and which impinges upon a brake disc (1) by means of at least one brake lining (20), wherein force sensors are arranged on the console (3) and/or on the brake caliper unit (10) and/or on connecting elements between the console (3) and the brake caliper unit (10), in order to detect braking torque (M_B) acting upon the brake disc (1). Said braking device is characterized in that the force sensors, can detect all forces, in particular at least three different forces (F₁, F₂, F2_a, F_2b, F₃) acting on the plane of the brake disc (1). The invention further relates to a method for determining a braking torque of a braking device.

Description

 DESCRIPTION

Braking device for a rail vehicle and method for determining a braking torque of a braking device

The invention relates to a braking device for a rail vehicle with a

Brake caliper unit which can be fastened via a bracket to a chassis of the rail vehicle and which acts on at least one brake pad on a brake disc. In this case, force sensors are arranged on the console and / or the brake caliper unit and / or on connecting elements between the bracket and the brake caliper unit in order to determine a braking torque acting on the brake disc. The invention further relates to a method for determining a brake torque acting on the brake disk in a braking device. In order to be able to control a braking device of a rail vehicle as precisely as possible during braking, a sufficiently accurate measurement of the braking torque which acts on the brake disk and thus on the braked vehicle axle is required during operation. If the measured braking torque is known, this can be adapted to a desired braking torque by appropriate control of the activation of an activator of the brake caliper unit. Instead of a technically difficult or impossible to implement direct measurement of the braking torque, this is usually calculated as the product of a frictional force, also called braking force, and a braking radius. The friction force refers to the force acting during braking due to the friction between the brake pad and the brake disc tangential force. The braking radius indicates the distance from the axis of rotation of the brake disc to the starting point of the friction force. In this case, average (effective) values for the braking force and the braking radius are assumed, which describe in summary the forces which are usually distributed over a larger area between the brake lining and the brake disk.

From the publication WO 2009/1 18 350 A2 a braking device of the aforementioned type is known, in which a plurality of force sensors are provided, which are mounted on the console of the brake caliper unit or the caliper unit itself and output the values correlated with the frictional force in a manner not described in detail. These values are compared as actual values with predetermined desired values in order to regulate the braking device with respect to its braking effect. From the publication WO 2010/069 520 A2 a similar arrangement is known in which two force sensors are provided which determine the force acting vertically in a spaced apart mounting points of the console on a console of a horizontally oriented brake caliper unit. The brake caliper unit is arranged along a horizontal axis, on which both the center of the

Brake disc, as well as the nominal force application point of the friction force. The two force sensors allow a quantitative determination of the frictional forces on the assumption that the nominal force application point lies on the said horizontal axis, that is to say has no horizontal force component in the case of tangential alignment. Due to various external factors, such as deflection of the chassis, contact pattern of the brake or an inhomogeneous distribution of the surface contact pressure between brake pad and brake disc, in practice, however, there is a shift of the point of force application of the friction force and, associated therewith, a rotation of the friction force vector. The assumption underlying the calculation of the frictional force that the force application point of the frictional force is on the horizontal axis are then no longer satisfied, whereby an incorrect value of the frictional force and thus of the

Braking torque is determined.

It is therefore an object of the present invention to provide a braking device or a method for determining a frictional force in a braking device, the determination of a correct value of the friction force and the displacement of the point of application of the frictional force during operation of the braking device

Enable braking torque. This object is achieved by a braking device or a method with the respective features of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims. A braking device according to the invention of the type mentioned above is characterized in that with the force sensors all acting in the plane of the brake disc and transmitted from the brake caliper unit in the console or in the bogie forces and force components are detected. By measuring not only mutually parallel forces in the suspension of the brake caliper unit and the friction force in the plane of the brake disc can be completely, ie with respect to the absolute value and the direction determined. As a result, the actual tangential frictional force can be determined and not only its projection on a given, for example, vertical axis. Accordingly, the actual braking torque can be determined.

In an advantageous embodiment of the braking device, the force sensors for measuring at least three different, acting in the plane of the brake disc forces are set up, wherein at least two of the forces are transverse to each other. With a suitable arrangement of the force sensors, the three sensors mentioned are sufficient to detect all transmitted from the brake caliper unit in the console or in the bogie forces and force components. Preferably, at least one of the forces runs entirely or at least with a force component in the direction of a longitudinal axis of the brake caliper unit. If, for example, the brake caliper unit is aligned horizontally with its longitudinal axis, advantageously at least one measured force is likewise aligned horizontally or has at least one horizontal force component.

In a further advantageous embodiment of the braking device, the connecting elements via which the brake caliper unit is connected to the console are three tension and pressure straps rotatably mounted on both sides, wherein the three different forces to be measured by the force sensors are along one of the tension and pressure straps Act. Preferably, two of the pull and push tabs are aligned parallel to each other and the third runs diagonally between the other two. This type of suspension allows a simple way of measuring the required three forces, for example by strain gauges as force sensors, which are arranged on the tension and pressure tabs, or by force sensors, which are arranged in the bearing points of the tension and pressure tabs. In an alternative embodiment of the braking device, the connection of the brake caliper unit to the chassis side console via a double-sided rotatably mounted pull and push tab and a single-sided rotatably mounted pull and push tab, wherein two of the three different forces along each one of the pull and push tabs and the other of the three different forces is a bending force in the one-sided rotatably mounted pull and push tab.

In a further alternative embodiment of the braking device is the

Brake caliper unit connected via a measuring console with two clamped on both sides tension and pressure ribs with the console, wherein two of the three different forces along each of the pull and pressure tabs and the other of the three different forces by bending forces in the clamped on both sides tension and pressure ribs is.

Even with these alternative suspensions of the brake caliper unit the measurement of the required three forces is possible in a simple manner, again e.g. by strain gauges or force sensors, which are arranged in the bearing points of the tension and pressure tabs.

A method according to the invention for determining a brake torque acting on a brake disk in a brake device has the following steps: At least three different forces are measured in the plane of the brake disk, the forces acting on a suspension of a brake caliper unit of the brake device, and at least two of the forces are transverse to each other.

Based on the at least three different forces, a frictional force acting in a middle friction radius between at least one brake pad and the brake disc is determined, and then from the frictional force and the mean friction radius, the braking torque. This results in the advantages mentioned in connection with the braking device according to the invention.

The invention will be explained in more detail by means of embodiments with the aid of figures. The figures show: Figure 1 to 3 are each a schematic side view of an embodiment of an application according to Bremseinreichtung. FIG. 1 shows a schematic side view of a braking device for a rail vehicle.

The Bremseinreichtung has a brake disc 1, which is rotatably mounted about a center 2. The brake disk 1 may be a shaft or a wheel brake disc in a known manner. Of the Bremsscheibel only an outer edge is shown act on the brake pads 20, of which a front, arranged on the side of the brake disc 1 shown here brake pad 20 is visible in Figure 1.

The brake pads 20 are held by a brake caliper unit 10 and upon actuation of the brake with a contact force perpendicular to the surface of

 Brake disc 1 pressed. The brake pads 20 are mounted for this purpose on brake calipers 1 1, which press the brake pads 20 on the brake disc 1 with the help of an unspecified here actuator 12. The brake caliper unit 10 has to

Attaching a mounting base 13, via which it is mounted with connecting elements 30 to a bracket 3. The console 3 is firmly anchored to a chassis, such as a bogie, a rail vehicle. Details of the connecting elements 30 between the chassis-side bracket 3 and the mounting base 13 of the brake caliper unit 10 will be explained in more detail below. With the brake device shown, an axle of a rail vehicle is braked by a braking torque M _B is exerted on this axis. This

Braking torque M _B results from a frictional force F _R , which acts between the brake pads 20 and the brake disc 1. The frictional force F _R acts tangentially on the brake disk 1 in a mean braking radius r _m , wherein the following applies to the braking torque M _B :

M _B = FR - r, m (Eq -1) - In the plane of the brake disc 1 are two orthogonal to each other

Defined directions, an x-direction and a y-direction. Starting from the center 2 of the brake disk 1, a coordinate system with x and y axes is defined by these two directions. In this case, the brake caliper unit 10 is arranged with a longitudinal axis along the x-axis. In the illustrated embodiment, the x-axis is horizontal, i. parallel to the rail on which the rail vehicle travels. However, in alternative embodiments, the caliper unit 10 could be installed inclined to the horizontal direction. In that case, the x-direction does not coincide with the horizontal direction.

Each surface element of the brake pads 20 contributes a proportion of the braking torque M _B , this proportion being dependent on the radius of the corresponding surface element (ie the distance of the surface element from the center 2 of the brake disc 1), the coefficient of friction and the pressure acting on the surface element. The braking torque M _B then results as an integral over the entire surface of the brake pads 20. Die

Frictional force of the individual surface elements results in the frictional force F _R , which acts on a mean friction radius r _m .

In general, the brake pads 20 and the brake caliper unit 10 are designed and positioned so that the centroid of the brake pads 20 is located on the x-axis.

Assuming that the contact pressure of the brake pads 20 is constant over the entire surface of the brake pads 20 and also the coefficient of friction across the surface of the friction pads 20 does not vary, the force application point of the braking force F _{R is} on the x-axis. In the case, the braking force F _R in the direction of the (negative) y-axis, the operating angle β, under which the force application point from the center 2 of the brake disc 1 is positioned, is equal to 0. In this case, the braking force F _{R has} no force component F _Rx in the x direction (F _Rx = 0). However, since the geometry of the braking device is not necessarily designed so that the force application point lies on the x-axis and also usually neither prevails over the surface of the brake pad constant contact pressure or friction, the force application point is often not on the x-axis, but from the center 2 seen from an effective angle ß not equal to zero. This leads to the braking force F _R having both a force component F _Ry in the y direction and a force component F _Rx in the x direction. The suspension of the brake caliper unit 10 explained in more detail below by the connecting elements 30 and the force measurement implemented thereby enables a correct determination of the braking force F _R taking into account the force component F _Rx in the x direction _. In the embodiment of Figure 1, the console 3 has two suspension points, a first chassis side suspension point 4 and a second chassis side suspension point 5. These two suspension points are spaced by a distance b from each other in the x direction. The two suspension points 4 and 5 can also be realized directly in the bogie. The console 3 would then be an integral part of the Drehges- telle and not, as shown here, a separate component.

In the y-direction, ie in this case in the vertical direction, both suspension points 4, 5 are arranged at the same height. The mounting base 13 on the brake caliper unit 10 also has two suspension points, a first bremszangenseitigen

Suspension point 14 and a second brake caliper side suspension point 15, which are equally spaced from each other by the distance b in the x direction.

The brake caliper unit 10 is now connected by three tension and pressure tabs 31 - 33 as connecting elements 30 to the console 3. The second pull and push tab 32 hingedly connects the second chassis-side suspension point 5 to the second brake-arm-side suspension point 15. Finally, the third pull-and-push link 32 hingedly connects the first chassis-side suspension point 4 to the second brake-arm-side suspension point 14. and pressure tab 33, the first bremskangenseitigen suspension point 14 with the second chassis side suspension point. 5 It is understood that the three mentioned pull and push tabs 31-33 may be extended in a direction perpendicular to the plane of the brake disc 1 to prevent rotation of the caliper unit 10 about the y axis. On the arrangement shown are three not shown here and sensitive to tension or pressure force sensors arranged, each measuring a tensile or compressive load of the respective pull and push tab 31 -33. The sensors can either be arranged as strain sensors, for example strain gauges, on the tension or pressure tabs 31 - 33 or can also be positioned in the pivot eyes on the suspension points 4, 5, 14, 15.

As a result, the three sensors are arranged to measure three forces Fi, F ₂ and F ₃ , which act in the direction of the longitudinal extent of the tension and pressure tabs 31-33. The three forces Fi - F ₃ are shown in FIG.

Fi is the first pull and push tab 31, F _{2 of} the second pull and push tab 32 and F _{3 of} the third pull and push tab 33 assigned. The forces Fi and F ₃ act in the direction of the y-axis and the negative y-axis. F ₂ acts in a direction which is inclined by the angle α with respect to the y-axis. This angle α is known and results from the distance b in the horizontal direction between the suspension points 4, 5 and 14, 15 and the distance of the suspension points 4, 5 and 14, 15 in the y-direction, the length of the first or third pull and push tab 31, 33 corresponds. In addition to the sizes b and a, which are known and thus predetermined, is still the position of the first bremszangenseitigen suspension point 14 relative to the center 2 of

Brake disc 1 previously known. This suspension has the coordinates e _x, e _{y, x} is thus spaced apart by the distance e in x-direction and by the distance e from the center _y 2 in the y-direction from the center. 2

During operation of the braking device, the forces Fi, F ₂ and F _{3 are} measured. In this case, the measured force F ₂ is divided into a force component of magnitude F ₂ ^■ cos (a) acting in the y direction and a force component of magnitude acting in the x direction

F ₂ ^"sin (a). Since the x and y components F _Rx, F _Ry of the braking force F _R from the jewei- To be applied forces or force components in the x and y direction of the forces Fi to F ₃ , applies:

F _Rx = -F ₂ ^' sin (a); F _Ry = Fi + F ₂ ^■ cos (a) - F ₃ (equation 2).

From the force components F _Rx and F _Ry , finally, the resulting braking force F _R and the effective angle β can be determined via the following trigonometric relationship:

F _R = (F _Rx ² + F _Ry ² ) ^{1 2} ; β = arctane (F _Rx / F _Ry ) (equation 3).

The forces F ₃ and F _Ry can be put into another relationship via the lever law:

F _Ry - a = F ₃ - b (equation 4).

For this equation 4, it is assumed that the mounting base 13 can rotate about the fixed in the space first brake caliper side suspension point 14, wherein a lever of length b is formed at the end of the force F ₃ acts. Weitehin an imaginary lever of length a is arranged in extension of the lever with the length b, at the end of the force F _R acts. The length a of the lever results from the intersection of the extended connection between the second brake caliper side suspension point 15 and the first brake caliper side suspension point 14 on the one hand, and the extension of the force line of action of the force F _R on the other. In this mathematically permissible shift of the friction force into this point of intersection, the x-component F _{Rx of} the force F _R irrelevant for the force F ₃ and Equation 4 is valid.

The length of the lever arm a is also connected via geometric or trigonometric functions with the average brake radius r _m and the coordinates e _x and e _y the position of the first bremskangenseitigen suspension point 14, whereby from equation 4 and the already calculated effective angle ß the mean braking radius r _m can be calculated. Thus, both the braking force F _R and the mean braking radius r _{m are} known, so that according to equation 1, the braking torque M _B can be determined. The braking torque M _B calculated in this way from the measured forces Fi to F ₃ can be used, for example, to set a desired braking torque that leads to a desired predetermined deceleration of the rail vehicle. The contact pressure with which the brake pads 20 are then pressed onto the brake disc 1 by the actuator 12 can be controlled so that the desired braking torque M _{B is} achieved.

FIG. 2 shows a second exemplary embodiment of a braking device according to the application in the same way as in FIG. The same reference numerals in this as in the next figure designate the same or the same elements as in FIG. 1. From the basic structure, the braking device of the second exemplary embodiment corresponds to that according to FIG. 1, the description of which is hereby explicitly referenced.

Different in the two embodiments, the connecting elements 30, with which the mounting base 13 of the brake caliper unit 10 is attached to the bracket 3. In the embodiment of Figure 2, instead of the first and second rotatably mounted on both sides pull and push tabs 31, 32 a rotatably mounted on one side pull and push tab 34 is provided. This is shown at

Embodiment on the side of the mounting base 13 of the brake caliper unit 10 firmly connected and rotatably mounted only in the associated first chassis side suspension point 4.

Two tension sensors are connected to this tension and pressure flap 34 mounted on one side, with which the forces Fi in the direction of the y-axis and F ₂ 'in the direction of the (negative) x-axis are measured. Both pressure sensors can turn as Biegebzw. Extension sensors can be arranged on the tensioning and pressure tab 34 mounted on one side or else in the bearing eye of the first chassis-side suspension point 4.

The second chassis-side suspension point 5 is as in the first embodiment via a double-mounted pull and push tab 33 with the associated

Suspension point 15 of the mounting base 13 connected. At this or in connection with this double-sided pull and push tab, the force F ₃ in

Measured direction of the (negative) y-axis. Again, the forces Fi to F _{3 are} measured during operation of the brake. The coordinates e _x and e _y , which presently indicate the position of the first frame-side suspension point 4 relative to the center 2 of the brake disk 1, and the distance b of the two chassis-side suspension points 4, 5 in the x direction are given geometrically.

Analogous to equations 2 in the first embodiment, the following relationships apply here:

F _R x = F ₂ ; FR _y = Fi - F3 (equation 5).

Equations 3 and 4 apply equally to the first embodiment. Again, from the measured forces Fi to F _3, both the braking force F _R and the effective angle β can be calculated, as well as the mean effective braking radius r _m and finally the braking torque M _B.

FIG. 3 shows a further exemplary embodiment of a braking device according to the invention in the same representation as in FIGS. 1 and 2. Reference is again made to the description, in particular to FIG.

Also, this embodiment differs in the nature of the connecting elements 30 between the bracket 3 and the mounting base 13 of the brake caliper device 10th

The connecting elements 30 between the bracket 3 and the mounting base 13 are clamped on both sides in this case. They are referred to below as clamped on both sides tension and pressure ribs 35, 36. The tension and pressure ribs 35 and 36 are for example part of a one-piece measuring console 37, which has a double H-profile in cross-section. Similar to the one-sided mounted pull and push tab 34 of the second embodiment, a sensor system is arranged here in each of the two clamped on both sides tension and pressure ribs 35, 36, which on the one facing in the y direction and the other pointing in the x direction Kraftkom- component can measure. The force acting in the y direction in the tension and pressure rib 35 clamped on both sides is designated as force Fi, the force acting in the y direction in the tension and pressure lug 36 clamped on both sides as force F ₃ . The respective force acting in the y direction is designated as force F _2a or F ₂ b. For example, strain gauges can be attached to both sides of the respective bi-directionally prestressed tension and pressure ribs 35, 36. From the sum of the strains or compressions results in the respective force component in the y direction. The difference between the two measured values of strain and compression gives the force component in the x-direction.

During operation of the braking device, the forces Fi, F _2a , F ₂ b and F _{3 are} measured. The distance b of the tension and pressure ribs 35, 36 prestressed on both sides and the coordinates e _x and e _y are predetermined by the geometry of the braking device. These coordinates describe the position of the first lever point in the suspension of the mounting base 13, which in the present case is given by the position of the center of the first bi-directionally prestressed tension and compression rib 35.

For the braking force components F _Rx and F _Ry , the following relationship holds: F _Rx = F _2a + F _2b ; F _Ry = Fi - F ₃ (equation 6).

The equations 3 and 4 described in connection with the first embodiment also apply in this case. Again, both the braking force F _R and the effective angle ß can be determined, as well as the effective mean braking radius r _m . From these quantities can be determined according to equation 1, the braking torque M _B.

LIST OF REFERENCE NUMBERS

1 brake disc

 2 center of the brake disc

3 console

 4 first chassis-side suspension point

 5 second chassis-side suspension point

10 brake caliper unit

1 1 brake caliper

 12 actuator

 13 mounting base

 14 first brake caliper side suspension point

15 second brake caliper side suspension point

20 brake pad

30 connecting element

 31 - 33 rotatably mounted on both sides pull and push tab 34 on one side rotatably mounted pull and push tab

35, 36 clamped on both sides tension and pressure rib

 37 Measuring console x, y Coordinates in the plane of the brake disc

F _R friction force

F _Rx x component of frictional force

F _Ry y component of frictional force

Fi, F ₂ , F ₃ measured force

F2a, F ₂ b measured force

r _m mean braking radius

M _B braking torque

ß effective angle

α orientation angle of the second pressure and pull tab _; , E _y Koordianten the first effective mounting point of the standardized Bremszangenein

 apparent lever arm length in x-direction

 Distance of the suspension points in x-direction

Claims

1 . Braking device for a rail vehicle with a brake caliper unit (10) which is attachable to a chassis of the rail vehicle via a bracket (3) and acts on at least one brake pad (20) on a brake disc (1), wherein on the console (3) and / or the brake caliper unit (10) and / or on connecting elements (30) between the bracket (3) and the brake caliper unit (10) force sensors are arranged to determine a brake disc (1) acting braking torque (M _B ), characterized in that with the force sensors all forces (Fi, F ₂ , F _2a , F ₂ b, F ₃ ) acting in the plane of the brake disc (1), transmitted by the brake caliper unit (10) into the console or into the bogie and force components are detectable. 2. Braking device according to claim 1, wherein the force sensors for measuring at least three different forces (Fi, F ₂ , F _2a , F _2b , F ₃ ) are arranged in the plane of the brake disc (1), wherein at least two of the forces ( Fi, F ₂ , F _2a , F _2b , F ₃ ) are transverse to each other. 3. Braking device according to claim 1 or 2, wherein at least one of the forces (Fi, F ₂ , F _2a , F ₂ b, F ₃ ) wholly or at least with a force component in the direction (x) of a Longitudinal axis of the brake caliper unit (10) extends. 4. Braking device according to one of claims 1 to 3, wherein the brake caliper unit (10) via three mutually rotatably mounted pull and pressure tabs (31, 32, 33) is connected to the console (3), wherein the forces (Fi, F ₂ , F ₃ ) along each one of the tension and pressure tabs (31, 32, 33) act. 5. Braking device according to claim 4, wherein two of the two sides rotatably mounted pull and pressure tabs (31, 32, 33) are aligned parallel to each other and the third of the pull and pressure tabs (31, 32, 33) extends diagonally between the other two , 6. Braking device according to one of claims 1 to 3, wherein the brake caliper unit (10) via a double-sided rotatably mounted pull and pressure tab (33) and a one-sided rotatably mounted pull and push tab (34) to the console (3) is connected, wherein two of the forces (Fi, F ₃ ) along each one of the pull and pressure tabs (33, 34) act and the other of the forces (F ₂ ) is a bending force in the one-sided rotatably mounted pull and push tab (34). 7. Braking device according to one of claims 1 to 3, wherein the brake caliper unit (10) via a measuring console (37) with two clamped on both sides tension and pressure ribs (35, 36) is connected to the console (3), wherein two of the forces (Fi, F ₃ ) along each one of the pull and pressure tabs (33, 34) act and another of the forces (F _2a , F ₂ b) by bending forces in the clamped on both sides tension and pressure ribs (35, 36) is given , 8. Braking device according to one of claims 1 to 7, wherein the force sensors are strain sensors on the tension and pressure tabs (31, 32, 33, 34) or tension and pressure ribs (35, 36). 9. Braking device according to one of claims 1 to 8, wherein the force sensors in the bearing points of the tension and pressure tabs (31, 32, 33, 34) are arranged. 10. A method for determining a braking torque acting on a brake disc (1) (M _B ) at a braking device with the following steps: - Measuring at least three different forces (Fi, F ₂ , F _2a , F _2b , F ₃ ) in the plane of the brake disc (1), which act on a suspension of a brake caliper unit (10) of the braking device, wherein at least two of the forces ( Fi, F ₂ , F _2a , F _2b , F ₃ ) are transverse to each other; Determining, based on the at least three different forces (Fi, F ₂ , F _2a , F _2b , F ₃ ), a frictional force (F _R ), in an average friction radius (r _m ) between at least one brake pad (20) and the Brake disc (1) acts; and Determining the braking torque (M _B ) from the friction force (F _R ) and the average friction radius (r _m ).