BRAKING DEVICE OF A VEHICLE WITH AN OPERATING BRAKE PEDAL DEVICE WITH AN INDUCTIVE POSITION DETECTION DEVICE

Description

[0001] The invention is based on a braking device of a vehicle with a service brake pedal device and with an inductive position detection device, as well as on a vehicle according to claim 12, which comprises a braking device.

[0002] A position detection device is known, for example, from EP 2 265 903 B1, and is used therein to detect the position of a position sensor coupled to a shift or actuating rod of a braking device or a transmission of a vehicle. The coil of the known position detection device is formed by a planar coil that surrounds the position sensor in a semicircle.

[0003] EP 3 194 221 B4 discloses a generic braking device comprising a service brake pedal device and an inductive position detection device, which comprises electrical magnetic coils wound on a coil body. In such a service brake pedal device, the axial actuation travel or the axial stroke of the plunger piston is measured within an electrical channel by means of an inductive position detection device, whereby this axial stroke then represents the braking request signal. The magnetic coils then enclose the plunger piston. In particular, two magnetic coils arranged axially one behind the other are provided. Furthermore, a helical spring arrangement axially supports the plunger piston on a valve piston actuating a double-seat valve. Such service brake pedal devices are used, for example, in purely electric or electro-pneumatic service brake systems of commercial vehicles.

[0004] In purely electric service brake systems, at least one electric brake circuit is present, with at least one electric brake value sensor integrated in the service brake pedal device, which generates an electric service brake request signal depending on an actuation of the service brake pedal, which is fed into an electronic brake control unit, which generates control commands for electric brake actuators depending on the service brake request signal.

[0005] In electro-pneumatic service brake systems, a priority electro-pneumatic service brake circuit is provided, to which an electrical channel of the service brake pedal device or foot brake module (FBM) is assigned, i.e. when the service brake pedal is actuated, an electrical brake value transmitter (sensor device plus evaluation electronics) arranged in the service brake pedal device generates an electrical service brake request signal, which is fed into an electronic brake control unit in order to control a pneumatic brake pressure corresponding to the service brake request signal in pneumatic service brake cylinders by appropriately controlling solenoid valves or pressure control modules.In parallel, the actuation of the service brake pedal causes a plunger piston connected to it by a plunger / plunger receptacle to actuate a relay or valve piston via a compression spring, which in turn controls a double-seat valve of the service brake pedal device in order to generate a pneumatic control pressure corresponding to the braking request in at least one pneumatic channel of the service brake pedal device, which then forms a braking pressure in the brake cylinders in subordinate, purely pneumatic service brake circuits if the priority electro-pneumatic service brake circuit has failed due to a defect.

[0006] In order to transmit the actuating force from the piston to the valve piston that actuates the double-seat valve and at the same time to give the driver a pressure feeling on his foot that corresponds to the actuation of the service brake pedal, the coil spring arrangement is provided, which axially supports the tappet piston on the valve piston that actuates the double-seat valve.

[0007] Further position detection devices are described in DE 10 2013 204957 A1, DE 10 2007 052162 A1, DE 199 13 869 A1, DE 199 13 869 A1, DE 11 08 449 B, DE 41 41 545 A1, US 2009 / 001968 A1, DE 299 23 127 U1, and DE 10 2014 210 618 A1. The measuring principle in each case is based on a change in the length of a spring used as a measuring coil, which changes its inductance.

[0008] The present invention is based on the object of designing the service brake pedal device in such a way that it is simpler in construction and also saves installation space. A vehicle is also to be provided that includes such a braking device.

[0009] This object is achieved according to the invention by the features of claims 1 and 12. Disclosure of the invention

[0010] The invention is based on a braking device for a vehicle, wherein the braking device has an inductive position detection device, wherein the braking device is designed as an electro-pneumatic or electric braking device and has a service brake pedal device which comprises at least the following: a) a service brake pedal, b) a plunger connected to the service brake pedal, c) a service brake pedal device housing, d) a plunger piston mounted axially movably in the service brake pedal device housing with a plunger receptacle into which the plunger engages, e) a service brake pedal device coil spring arrangement which axially supports the plunger piston on a valve piston actuating a seat valve or on a housing section of the service brake pedal device housing, wherein f) the inductive position detection device is designed for contactless detection of a position of a position sensor and comprises at least the following: f1) a position detection device housing, f2) a coil which generates a magnetic field in a magnetic field region, f3) a measuring and evaluation device functionally coupled to the coil, f4) the position sensor, f5) a relative to the Position detection device housing movable actuator,by means of which a position of the position sensor can be changed, wherein the position sensor is arranged and configured in the magnetic field region such that a change in the position of the position sensor with respect to the magnetic field causes a change in the inductance of the coil, f6) a position detection device coil spring arrangement with at least one coil spring which exerts spring forces on the position sensor, wherein f7) the measuring and evaluation device has a function with which the change in the inductance of the coil is detected and the position of the position sensor is determined therefrom, wherein g) the plunger forms an actuating rod and is encompassed by the actuating device of the position detection device or forms the actuating device of the position detection device, and wherein h) the plunger piston is encompassed by the position sensor of the position detection device or forms the position sensor of the position detection device,and wherein i) the service brake pedal device coil spring assembly is comprised by the position detection device coil spring assembly or forms the position detection device coil spring assembly, and wherein j) the service brake pedal device housing is comprised by the position detection device housing or forms the position detection device housing. ,

[0011] According to the invention it is then provided that k) the at least one helical spring is designed and arranged such that it at least partially forms the coil, and that I) the at least one helical spring is electrically conductively connected to the measuring and evaluation device.

[0012] The position detection device thus uses at least one coil that generates a magnetic field and at least one position sensor arranged in the region of the magnetic field. The coil and the position sensor are movable relative to each other, and the position sensor generates eddy current losses that cause a change in the coil's inductance. The measuring and evaluation device detects the change in the coil's inductance and uses this to determine the position of the position sensor.

[0013] The position detection device coil spring arrangement can be provided for exerting spring forces on the position sensor for various purposes, for example, so that the position sensor is always preloaded by the spring forces along an actuation path that encompasses different positions of the position sensor and is thus guided in a defined manner. The at least one coil spring is preferably designed to exert tensile or compressive forces on the position sensor.

[0014] In other words, the at least one helical spring then performs the function of the coil by generating the magnetic field in the magnetic field region and is functionally coupled to the measuring and evaluation device. This is possible because the at least one helical spring has helical turns, similar to the coil turns of a magnetic coil, through which a magnetic field can be generated as a result of electrical excitation (energization) by means of the measuring and evaluation device. Therefore, the at least one helical spring is formed from an electrically conductive material that is capable of generating a magnetic field when an electrical current flows through it. Consequently, the helical turns of the at least one helical spring form coil turns of at least one coil.

[0015] The at least one coil spring thus has an advantageous dual function: on the one hand, it exerts spring forces on the position sensor for the reasons mentioned above, and on the other hand, it performs the function of the coil, which can then be omitted as a separate or additional component of the position detection device. Therefore, the invention reduces the number of components, the installation space, and the weight of the position detection device.

[0016] The measures listed in the subclaims enable advantageous further developments and improvements of the invention specified in claim 1.

[0017] Particularly preferably, the position sensor is made of an electrically conductive material. The position sensor can also be made of a non-magnetic material, in particular aluminum and / or copper.

[0018] The function of the measuring and evaluation device is preferably designed in such a way that it can determine a distance traveled by the position sensor.

[0019] The actuating device can also comprise an actuating rod. The position sensor can be fixed to the actuating rod by force, material, and / or form-fitting means and / or contact the actuating rod in such a way that the position of the position sensor can be changed.

[0020] The service brake pedal device coil spring arrangement can also wrap around at least one axial section of the tappet piston when viewed in the axial direction.

[0021] The service brake pedal device coil spring assembly can also be supported on the one hand on the tappet piston and on the other hand on at least one spring plate, which is arranged to transmit axial force relative to the valve piston, the tappet piston, or the housing section. At least the spring plate, the tappet piston, the valve piston, and the service brake pedal device coil spring assembly can be arranged coaxially.

[0022] In particular, the service brake pedal device coil spring arrangement can have a plurality of coil springs arranged in parallel.

[0023] A first coil spring of the service brake pedal device coil spring arrangement can also be constantly preloaded between the plunger piston and the spring plate, but a second coil spring of the service brake pedal device coil spring arrangement can be supported at one end on the spring plate and only come into contact with the plunger piston with its other end after the plunger piston has traveled a certain application stroke. This can create an actuation force / actuation travel characteristic curve in which the actuation force increases abruptly starting at a certain actuation travel, stroke, or angle of the service brake pedal.

[0024] Last but not least, the invention comprises a vehicle with a braking device as described above. drawing

[0025] The invention is described in more detail below using an exemplary embodiment with reference to the accompanying drawing. The single figure shows a schematic longitudinal section through a preferred embodiment of an upper part of a service brake pedal device, which has a preferred embodiment of a position detection device. Description of the embodiment

[0026] The upper part of an electro-pneumatic service brake pedal device 1 or an electro-pneumatic service brake valve or foot brake module shown in the figure as a preferred embodiment of the invention is a component of an electro-pneumatic braking device of a commercial vehicle. The electro-pneumatic service brake device has, for example, one electric brake circuit and two pneumatic service brake circuits.

[0027] The service brake pedal device 1 includes, among other things, a plunger 2 actuated by a service brake pedal (not shown), which engages in a plunger receptacle 3 of a plunger piston 6 axially movable in a housing 4. The plunger piston 6 has a piston skirt 8, on which a helical compression spring arrangement 9, consisting, for example, of two parallel and coaxially arranged helical springs, a first, for example outer, helical spring 5 and a second, for example inner, helical spring 7, is supported at one end, the other end being supported on a valve piston 10 via an intermediate spring plate 16. The plunger piston 6 is made, for example, of paramagnetic material, in particular aluminum. The inner or second helical spring 7 is also made of a paramagnetic material.

[0028] An adjusting screw 11, with its adjusting screw head 24, is screwed into an internal thread of a blind bore 18 of the tappet piston 6, facing away from the tappet receptacle 3, with an external thread of its adjusting screw shaft 20. It is arranged centrally and coaxially with respect to the helical compression spring arrangement 9. It is guided axially movably in a bore 26 of the valve piston 10 facing the tappet piston 6. The guiding of the adjusting screw head 24 in the bore 26 of the valve piston 10 consists, for example, of an axial plain bearing. This bore 26 is, in particular, a through-bore in the valve piston 10.

[0029] The adjusting screw protrudes with its adjusting screw shaft 20 through a central through-bore 27 of the spring plate 16, wherein the adjusting screw head 24 comes to rest on the edge of the through-bore 27 and is thereby counter-locked there because its outer diameter is larger than the inner diameter of the through-bore 27.

[0030] The spring plate 16 is then clamped between the valve piston 10 and the coil spring assembly 9. Furthermore, a replaceable spacer element 29 can be arranged between the spring plate 16 and the valve piston 10. The threaded connection formed by the internal thread of the blind hole 18 and the external thread of the adjusting screw 11 is preferably a self-locking thread. Furthermore, the coil springs 5, 7 of the coil spring assembly 9 are preferably made of paramagnetic material.

[0031] The valve piston 10 is supported on the housing 4 via a third coil spring 28, only partially visible in the figure. Furthermore, the valve piston 10, with its piston surface facing away from the coil spring arrangement 9, defines a working chamber 30, which is connected via a working port of the housing 4 to a brake pressure line leading to pneumatic wheel brake cylinders.

[0032] The valve piston 10 actuates, in a known manner, a double-seat valve (not shown here for reasons of scale), to connect the working port or the working chamber either to a vent (driving position) or to a supply port (braking position), to which a supply pressure line leading to a compressed air supply is connected. The working port is connected via a pneumatic pressure line of the pneumatic service brake circuit to a pneumatic connection of a pressure control module, which further routes the pneumatic service brake circuit to pneumatic service brake cylinders via an integrated backup solenoid valve. Therefore, depending on the actuation state of the double-seat valve, the working chamber is connected either to a vent or to a compressed air supply.

[0033] Furthermore, a contactless position detection device 100 operating according to the inductive principle is provided. The position detection device 100 comprises the housing 4, which here represents a common housing with the service brake pedal device 1, the plunger piston 6 as a position sensor, a measuring and evaluation device 34, the plunger 2, which is movable relative to the housing 4 and by means of which an axial position of the plunger piston 6 can be changed, and the coil spring arrangement with the first coil spring 5 and the second coil spring 7.

[0034] The first coil spring 5 and the second coil spring 7 are electrically connected to an electronic measuring and evaluation device 14 arranged in an electronics housing 32 flanged to the housing 4 on a peripheral section. The components of the measuring and evaluation device 14 are arranged on a circuit board 34 which, when the electronics housing 32 is installed, is parallel to a central axis 36 of the service brake pedal device 1, for example. The first coil spring 5 and the second coil spring 7 enclose, in particular, the piston skirt 8 of the tappet piston 6 in a ring shape, so that the piston skirt 8 of the tappet piston 6 can move axially within the first coil spring 5 and the second coil spring 7 when the tappet piston 6 moves axially as a result of a movement of the tappet 2, i.e. changes its axial position.The measuring and evaluation device 14 is designed to energize the first coil spring 5 and the second coil spring 7, generating a magnetic field with a magnetic field range as a result of the energization, which magnetic field detects the plunger piston 6, in particular the piston skirt 8 of the plunger piston 6. A change in the axial position of the plunger piston 6 causes a change in the inductance of the first coil spring 5 and the second coil spring 7, which is detected by the measuring and evaluation device 14 and on the basis of which the position or position change of the plunger piston 6 is then determined without contact.

[0035] Furthermore, a housing cover 22 is attached to the head of the housing 4. An upper stop for the plunger piston 6 can be formed by a guide body 38, which is held in the head of the housing 4 and in whose central bore the plunger piston 6 is sealingly guided.

[0036] The housing 4, the tappet 2, the tappet piston 6, the spring plate 16, the coil spring arrangement 9, the valve piston 10, the adjusting screw 11, the guide body 38 and the housing cover 22 are arranged essentially coaxially with the central axis 36, ie possibly with locally deviating shapes due to design reasons, such as those caused by the electronics housing 32.

[0037] An upper end position of the plunger piston 6, in which it strikes the guide body 38, then marks the driving state with the service brake released, in which the plunger 2 is unloaded from the service brake plate and the valve piston 10 is lifted from a valve body of the double-seat valve axially guided in the housing 4. This allows compressed air to flow from the working port through the working chamber into the vent, resulting in venting of the pneumatic service brake circuit. The measuring and evaluation device 14 generates a corresponding electrical (zero) service brake request signal.

[0038] When the driver then applies the service brake plate with their foot from the driving position, the tappet 2 and thus also the tappet piston 6 move axially downward. This movement is transmitted to the valve piston 10 exclusively by the first coil spring 5 up to an initial stroke. Once the initial stroke is overcome, the tappet piston 6 comes into contact with the second coil spring 7, whereby the second coil spring 7 now also transmits the actuating force to the valve piston 10. As explained above, the tappet piston 6 moves axially as a result of the movement of the tappet 2, i.e., its axial position changes.When the piston skirt 8 of the plunger piston 6 plunges deeper into the first coil spring 5 and the second coil spring 7 in the axial direction due to actuation of the service brake plate, the first coil spring 5 and the second coil spring 7 change their inductance L, which can be detected in a known manner by the measuring and evaluation device 14, which then, by means of a circuit integrated on the circuit board 34, forms an electrical service brake request signal proportional to the axial movement of the plunger piston 6 from the changed inductance L of the first coil spring 5 and the second coil spring 7. Since the plunger piston 6 is made, in particular, of paramagnetic material, it weakens the magnetic field generated by the first coil spring 5 and the second coil spring 7 when it plunges into it.

[0039] Since the valve piston 10 is supported on the housing 4 via the third coil spring 28, the two coil springs 5, 7 of the coil spring arrangement 9 are compressed by a compression path, so that the adjusting screw head 24 of the adjusting screw 11 dips into the bore 26 of the valve piston 10 to compensate for this compression path, as can easily be imagined from the figure.

[0040] The measuring and evaluation device 14 is connected via a digital interface (A / D converter) to a communication line (not shown here), for example, to a data bus to which a central electronic brake control unit of the electro-pneumatic service brake system is also connected, so that the electrical service brake request signal is fed into this electronic brake control unit within the electrical service brake circuit. In the brake control unit, the service brake request signal can then be modified axle-by-axle or wheel-by-wheel through higher-level functions such as automatic axle-load-dependent brake pressure control, differential slip control, etc., before being fed into the pressure control modules of the front axle or rear axle.Local control units are installed in the pressure control modules. These then use an inlet / outlet solenoid valve combination, which pre-controls a relay valve, to generate a brake pressure in the assigned pneumatic service brake cylinder(s) that is dependent on the service brake request signal. A pressure sensor integrated into each of these pressure control modules then regulates the actual brake pressure by adjusting it to a target brake pressure represented by the service brake request signal.

[0041] To adjust the preload of the coil spring assembly 9, the adjusting screw 11 is simply turned in the internal thread of the plunger piston 6. For this purpose, the adjusting screw head 24 has a mounting surface for a tool, in particular for an Allen key, whereby the tool can be inserted via the other end of the through-bore 26 even in the assembled state.

[0042] The invention is not limited to the embodiment described above. The position detection device 100 can also be comprised, for example, by a service brake pedal device 1 of a purely electric braking device, which only has at least one electrical channel. Instead of being supported on the valve piston 10, the coil spring arrangement 9 is then supported on a base of the housing 4, which then has the bore 26 for guiding the adjusting screw head 24.

[0043] Likewise, the position detection device 100 can also be included in a transmission of a vehicle, which has at least one shift rod or an actuating rod preloaded by a transmission coil spring arrangement, wherein the position detection device is configured to detect the position of the shift rod or the actuating rod. Then, the transmission coil spring arrangement is included in the position detection device coil spring arrangement or forms the position detection device coil spring arrangement to achieve the effects described above. List of reference symbols

[0044] 1Service brake pedal assembly 2Plunger 3Plunger receptacle 4Housing 5First coil spring 6Plunger piston 7Second coil spring 8Piston skirt 9Coil spring assembly 10Valve piston 11Setting screw 14Measuring and evaluation device 16Spring plate 18Blind hole 20Setting screw shaft 22Housing cover 24Setting screw head 26Bore 27Through hole 28Third coil spring 29Spacer element 30Working chamber 32Electronics housing 34PCB 36Central axis 38Guide body 100Position detection device

Claims

1. Braking apparatus for a vehicle, wherein the braking apparatus has an inductive position detection device (100), wherein the braking apparatus is designed as an electropneumatic or electric braking apparatus, and has a service brake pedal apparatus (1), which comprises at least the following: a) a service brake pedal, b) a tappet (2) connected to the service brake pedal, c) a service brake pedal apparatus housing (4), d) a tappet piston (6) mounted in an axially displaceable manner in the service brake pedal apparatus housing (4) with a tappet holder (3), in which the tappet (2) engages, e) a service brake pedal apparatus coil spring arrangement, which axially supports the tappet piston (6) on a valve piston (10) operating a seat valve or on a housing section of the service brake pedal apparatus housing, wherein f) the inductive position detection device (100) is designed for contactless detection of a position of a position sensor and comprises at least the following: f1) a position detection device housing (4), f2) a coil, which generates a magnetic field in a magnetic field region, f3) a measurement and evaluation apparatus (34) functionally coupled to the coil, f4) the position sensor, f5) an actuating apparatus (2) that can be moved relative to the position detection device housing (4), by means of which a position of the position sensor can be changed, wherein the position sensor is arranged in the magnetic field region and is designed such that a change in the position of the position sensor in relation to the magnetic field causes a change in inductance of the coil, f6) a position detection device coil spring arrangement (9) with at least one coil spring (5, 7), which exerts spring forces on the position sensor, wherein f7) the measurement and evaluation apparatus (34) has a function, with which the change in inductance of the coil is detected and the position of the position sensor (6) is determined therefrom, wherein g) the tappet (2) forms an actuator rod and is comprised of the actuating apparatus of the position detection device (100) or forms the actuating apparatus of the position detection device (100), and wherein h) the tappet piston (6) is comprised of the position sensor of the position detection device (100) or forms the position sensor of the position detection device (100), and wherein i) the service brake pedal apparatus coil spring arrangement is comprised of the position detection device coil spring arrangement (9) or forms the position detection device coil spring arrangement (9), and wherein j) the service brake pedal apparatus housing is comprised of the position detection device housing (4) or forms the position detection device housing (4), characterized in that k) the at least one coil spring (5, 7) is designed and arranged such that it at least partially forms the coil, and in that l) the at least one coil spring (5, 7) is electrically conductively connected to the measurement and evaluation apparatus (34).

2. Braking apparatus according to claim 1, characterized in that the position sensor is made from an electrically conductive material.

3. Braking apparatus according to claim 1 or 2, characterized in that the position sensor is made from a non-magnetic material.

4. Braking apparatus according to any one of claims 1 to 3, characterized in that the position sensor is made from aluminum and / or copper.

5. Braking apparatus according to any one of the preceding claims, characterized in that the function of the measurement and evaluation apparatus (10) is designed such that it can determine a path (s) traveled by the position sensor (6).

6. Braking apparatus according to any one of the preceding claims, characterized in that the position sensor is fixed in a force-fitting, material-fitting and / or form-fitting manner to the actuator rod and / or contacts the actuator rod such that the position of the position sensor can be changed.

7. Braking apparatus according to any one of the preceding claims, characterized in that, when viewed in an axial direction, the service brake pedal apparatus coil spring arrangement (9) loops around at least one axial section of the tappet piston (6).

8. Braking apparatus according to any one of the preceding claims, characterized in that the service brake pedal apparatus coil spring arrangement (9) is supported, on the one hand, on the tappet piston (6) and, on the other hand, on at least one spring plate (16), which is arranged so as transmit axial force in relation to the valve piston (10), the tappet piston (6) or the housing section.

9. Braking apparatus according to any one of the preceding claims, characterized in that at least the spring plate (16), the tappet piston (6), the valve piston (10) and the service brake pedal apparatus coil spring arrangement (9) are arranged coaxially.

10. Braking apparatus according to any one of the preceding claims, characterized in that the service brake pedal apparatus coil spring arrangement (9) has multiple coil springs (5, 7) arranged in parallel.

11. Braking apparatus according to claim 10, characterized in that a first coil spring (5) is constantly pretensioned between the tappet piston (6) and the spring plate (16), but a second coil spring (7) is supported with its one end on the spring plate (16) and with its other end only coming to rest on the tappet piston (6) after a certain application stroke of the tappet piston (6) has been traveled.

12. Vehicle comprising a braking apparatus according to any one of the preceding claims.