Actuation unit for a braking system

Abstract

The invention relates to an actuation unit (1) for a braking system (2), having an actuatable main brake cylinder (10), comprising a transmission unit (12) having a moveably mounted transmission element (13), comprising an electric motor (8) for driving the transmission unit (12), comprising a moveably mounted pressure force transmitter (20) which is connected to an input rod (24) in such a way that the pressure force transmitter (20) can be shifted by the input rod (24), wherein the main brake cylinder (10) can be actuated both by a shifting of the transmission element (13) and by a shifting of the pressure force transmitter (20), and comprising a sensor (30) having a first sensor part (32) that can be shifted alongside the pressure force transmitter (20) and a second sensor part (33) that can be shifted alongside the transmission element (13). According to the invention, the first and the second sensor part (32, 33) are moveably mounted on a common carrier element (31) of the sensor (30).

Description

[0001] Description

[0002] title

[0003] Actuating device for a braking system

[0004] The invention relates to an actuating device for a brake system having an actuatable master brake cylinder, with a transmission device having a displaceably mounted transmission element, with an electric motor for driving the transmission device, with a displaceably mounted pressure force transmitter which is connected to an input rod in such a way that the pressure force transmitter can be displaced by the input rod, wherein the master brake cylinder can be actuated both by a displacement of the transmission element and by a displacement of the pressure force transmitter, and with a sensor which has a first sensor part which can be displaced together with the pressure force transmitter and a second sensor part which can be displaced together with the transmission element.

[0005] State of the art

[0006] A hydraulic braking system of a motor vehicle typically has several friction brake devices that are hydraulically connected to a master brake cylinder of the braking system. When the master brake cylinder is actuated, hydraulic fluid is displaced into the slave cylinders of the friction brake devices, so that the friction brake devices then generate a friction braking torque. An actuating device is typically present to actuate the master brake cylinder. With the increasing electrification of motor vehicles, actuating devices of braking systems are also becoming increasingly electrified. An actuating device of the type mentioned above is known, for example, from published patent application DE 10 2019 203 511 A1. The actuating device has a transmission device with a displaceably mounted transmission element. The transmission device can be driven by an electric motor of the actuating device.The actuating device also has a movable pressure force transmitter. The pressure force transmitter is connected to an input rod such that the pressure force transmitter can be moved by the input rod. If the actuating device is installed in the braking system as intended, the master brake cylinder can be actuated both by moving the transmission element and by moving the pressure force transmitter. The actuating device also has a sensor, which has a first sensor part that can be moved along with the pressure force transmitter and a second sensor part that can be moved along with the transmission element. The sensor can detect a sliding position of the pressure force transmitter relative to a sliding position of the transmission element. In the actuating device known from published patent application DE 10 2019 203 511 A1, the first sensor part is a sensor transmitter.The second sensor part is a sensor receiver. The first sensor part and the second sensor part are attached to the pressure force transmitter and the transmission element, respectively.

[0007] Disclosure of the invention

[0008] The actuating device according to the invention, with the features of claim 1, is characterized in that the first sensor part and the second sensor part are movably mounted on a common support element of the sensor. By mounting both the first sensor part and the second sensor part on the common support element, the elements of the sensor can be easily handled together as an assembly. This significantly simplifies the installation of the sensor in the actuating device, as well as the disassembly of an installed sensor, compared to previously known solutions. The support element is preferably made of plastic.

[0009] According to a preferred embodiment, the support element is frame-shaped, and the first and second sensor parts are displaceably mounted in a frame opening of the support element. By being mounted in the frame opening, the first and second sensor parts are protected from damage by the support element. The frame-shaped support element preferably has two first legs aligned in the direction of displacement of the sensor units and two second legs aligned perpendicular to the direction of displacement, so that the frame is rectangular. Particularly preferably, the sensor parts are displaceably mounted by the first legs of the frame-shaped support element. The first legs therefore contribute to the mounting of the sensor parts.

[0010] According to a preferred embodiment, at least one guide rod, in particular a metal one, is fastened to the support element, and the first sensor part and the second sensor part are displaceably mounted by the guide rod. The guide rod ensures a particularly robust mechanical support of the first sensor part and the second sensor part. Preferably, the first and second sensor parts are plugged or pushed onto the guide rod. Particularly preferably, a plurality of guide rods arranged parallel to one another are fastened to the support element, wherein the first sensor part and the second sensor part are then displaceably mounted by the plurality of guide rods.

[0011] Preferably, the first and second sensor parts are mounted one behind the other on the support element in the sliding direction. Such an arrangement of the sensor parts allows for the realization of a sensor with a narrow width.

[0012] According to an alternative embodiment, the sensor parts are arranged next to each other, for example in the sliding direction.

[0013] According to a preferred embodiment, the actuating device comprises a housing in which the transmission element and the pressure force transmitter are at least partially arranged, and the sensor is attached to the housing. This embodiment of the actuating device is mechanically particularly robust. In particular, the sensor is attached to the housing by means of the support element. Preferably, the sensor is detachably attached to the housing. This simplifies the replacement of an installed sensor. Particularly preferably, the sensor is attached to the housing by a detachable screw connection.

[0014] According to a preferred embodiment, the sensor is inserted into an opening in a casing wall of the housing. Inserting it into the opening ensures that both the mechanical coupling of the first sensor part and the second sensor part to the pressure force transmitter or the transmission element, as well as an electrical connection to a control unit arranged outside the housing, are technically easy to implement. Preferably, the sensor is inserted into the opening such that the first sensor part and the second sensor part face the interior of the housing.

[0015] According to a preferred embodiment, a first driver element is fastened to the pressure force transmitter, wherein the first driver element is connected to the first sensor part by a positive connection. The positive connection ensures that the first sensor part is securely displaced together with the pressure force transmitter, wherein the positive connection is designed to transmit forces acting at least in the direction of displacement of the pressure force transmitter to the first sensor part. The first driver element can be fastened to the pressure force transmitter both directly and indirectly. Alternatively or additionally, the actuating device preferably has a second driver element fastened to the gear element, wherein the second driver element is connected to the second sensor part by a positive connection.

[0016] To form the positive connection, the first driver element preferably cooperates with a fork-shaped retaining structure of the first sensor part. Such a positive connection reliably ensures that the first sensor part is displaced along with the pressure force transmitter. Furthermore, the positive connection is easy to form, namely by inserting the first driver element into the fork-shaped retaining structure. Alternatively or additionally, the second driver element cooperates with a fork-shaped retaining structure of the second sensor part to form the positive connection.

[0017] According to a preferred embodiment, the first driver element is fastened to the first sensor part by a snap-in connection or a clamp-in connection. This ensures a particularly robust mechanical connection between the first driver element and the first sensor part, so that the connection can withstand, for example, vibrations from the actuating device. In addition, a snap-in connection or a clamp-in connection is easy to produce when installing the sensor in the actuating device, for example by plugging together the first driver element and the first sensor part. The snap-in connection or the clamp-in connection is preferably designed to be detachable. This has the advantage that the sensor can be easily replaced. The second driver element is preferably fastened to the second sensor part by a snap-in connection, in particular a detachable, or a clamp-in connection, in particular a detachable.

[0018] According to a preferred embodiment, the sensor has a printed circuit board on the carrier element, on which at least one receiver coil is formed. The receiver coil is therefore formed by conductor tracks of the printed circuit board. Such a design of the receiver coil is technically simple and cost-effective to implement. By attaching the printed circuit board to the carrier element, the electrical connection of the printed circuit board or the receiver coil, for example, to a control unit is simplified. If the printed circuit board or the receiver coil were slidably mounted on the carrier element, the electrical connection to the control unit would at least be more difficult. The receiver coil can be used to realize contactless detection of the sliding position of the first sensor part and the second sensor part. The sensor is preferably designed as an inductive sensor.Particularly preferably, the circuit board has a transmitter coil and two receiver coils. As previously mentioned, the carrier element is preferably frame-shaped. The circuit board is then preferably arranged such that it covers or closes the frame opening of the carrier element. According to an alternative embodiment, the first sensor part or the second sensor part is designed as a receiver. The second sensor part or the first sensor part is then designed as a measured value transmitter.

[0019] According to a preferred embodiment, the circuit board has at least one electrically conductive contact plate for electrically contacting a control unit. Such contact plates are technically easy to contact, for example, using electrically conductive contact springs on the control unit side. As previously mentioned, the sensor preferably has a transmitter coil and two receiver coils. The circuit board then preferably has six electrically conductive contact plates, with two of the contact plates being assigned to each of the coils. Particularly preferably, the contact plates are arranged one behind the other in a row.

[0020] According to a preferred embodiment, it is provided that the first sensor part comprises an electrically conductive material and is arranged such that an electrical voltage of the receiver coil can be influenced by a sliding position of the first sensor part, and / or that the second sensor part comprises an electrically conductive material and is arranged such that the electrical voltage of the receiver coil can be influenced by a sliding position of the second sensor part. This results in a particularly advantageous inductive sensor. Particularly preferably, the first and / or the second sensor part each have a base body made of plastic, wherein the electrically conductive material is arranged on a side of the base body facing the receiver coil.

[0021] The actuating device preferably has a control unit that is arranged on the housing of the actuating device such that the control unit covers the sensor. By arranging the control unit in this way, the sensor is protected from external influences by the control unit. Furthermore, the connection of the sensor to the control unit is simplified because the control unit is located in the immediate vicinity of the sensor. The control unit is preferably electrically connected to the circuit board. Particularly preferably, the electrical connection is realized by contact springs on the control unit side, which are in touching contact with the aforementioned contact plates on the circuit board side. The control unit is preferably designed to control the electric motor depending on a sensor signal from the sensor.

[0022] According to a preferred embodiment, the control unit has a control unit housing, and the sensor is arranged in an opening in a casing wall of the control unit housing. This further increases the protection of the sensor against external influences and also further simplifies the connection of the sensor to the control unit. Preferably, the sensor protrudes into the control unit in such a way that the sensor's circuit board is arranged inside the control unit housing.

[0023] The invention is explained in more detail below with reference to the drawings.

[0024] Figure 1 is a perspective view of an actuating device for a braking system,

[0025] Figure 2 is a sectional view of the actuating device,

[0026] Figure 3 shows a sensor of the actuating device,

[0027] Figure 4 shows another representation of the sensor,

[0028] Figure 5 shows the sensor coupled with elements of the actuating device,

[0029] Figure 6 shows a housing of the actuating device and

[0030] Figure 7 shows a further illustration of the actuating device.

[0031] Figure 1 shows a perspective view of an actuating device 1 for a braking system 2 of a motor vehicle (not shown in detail). The actuating device 1 has a housing 3. The housing 3 is tubular and therefore has a circumferential jacket wall 4 that encloses an interior 5 of the housing 3. The actuating device 1 also has a drive unit 6 arranged on the housing 3. The drive unit 6 has an electric motor 8, which is arranged in a motor housing 7 and is therefore not visible in Figure 1. In addition, the actuating device 1 has a control unit 9. The control unit 9 is arranged on a side of the housing 3 facing away from the drive unit 6. The control unit 9 is designed to control the electric motor 8.A master brake cylinder 10 is arranged on one end face of the housing 3, in which two hydraulic pistons 11 are displaceably mounted. If the actuating device 1 is installed as intended in the brake system 2, the master brake cylinder 10 is fluidly connected to slave cylinders of friction brake devices of the brake system 2.

[0032] Figure 2 shows a longitudinal section of the actuating device 1. The actuating device 1 has a gear device 12. The gear device 12 is operatively connected to the electric motor 8 such that the gear device 12 can be driven by the electric motor 8. The gear device 12 has a displaceably mounted gear element 13, wherein the gear element 13 is at least partially arranged in the housing 3. The gear element 13 is displaceable in a first direction 14 and in a second direction 15 opposite the first direction 14. In the present case, the gear element 13 is a threaded spindle 13, which is part of a spindle gear 16. In addition to the threaded spindle 13, the spindle gear 16 has a rotatably mounted spindle nut 17. An internal toothing of the spindle nut 17 meshes with an external toothing of the threaded spindle 13.To ensure that the threaded spindle 13 is displaced when the spindle nut 17 rotates instead of rotating with the spindle nut 17, the threaded spindle 13 is assigned an anti-rotation device 18. For this purpose, an anti-rotation element 19 is provided, which is fastened to the threaded spindle 13, in this case to an end of the threaded spindle 13 facing the master brake cylinder 10. The anti-rotation element 19 cooperates with the housing 3 to form the anti-rotation device 18. In this case, a pot-shaped thrust body 26 is fastened to the anti-rotation element 19. The actuating device 1 also has a pressure force transmitter 20 that is displaceably mounted relative to the gear element 13, wherein the pressure force transmitter 20 is also arranged at least partially in the housing 3. The pressure force transmitter 20 is displaceable in the first direction 14 and in the second direction 15.In the present case, the pressure force transmitter 20 is mounted in an opening 21 of the transmission element 13. According to the exemplary embodiment shown in Figure 2, the pressure force transmitter 20 is designed in several parts. For this purpose, the pressure force transmitter 20 has a rod-shaped section 22 arranged in the opening 21. In addition, the pressure force transmitter has a pressure cap 23 arranged on an end of the pressure force transmitter 20 facing the master brake cylinder 10. The pressure cap 23 is fastened to the rod-shaped section 22, in this case by crimping. An end of the pressure force transmitter 20 facing away from the master brake cylinder 10 is connected to an input rod 24, such that the pressure force transmitter 20 can be displaced by the input rod 24. In the present case, the pressure force transmitter 20 is connected to the input rod 24 by a ball joint 25.An end of the input rod 24 facing away from the pressure force transmitter 20 is attached to a brake pedal, not shown.

[0033] The master brake cylinder 10 can be actuated both by displacing the transmission element 13 and by displacing the pressure force transmitter 20. Actuating the master brake cylinder 10 means displacing the hydraulic pistons 11 in the first direction 14. If the actuating device 1 is installed as intended in the brake system 2, this displaces hydraulic fluid from the master brake cylinder 10 into the slave cylinders of the friction brake devices, so that the friction brake devices then generate a friction braking torque. In this case, the transmission element 13 and the pressure force transmitter 20 are operatively connected or can be operatively connected to the hydraulic pistons 11 by a coupling element 27. The coupling element 27 has an elastically deformable coupling disc 28 and a rigid push rod 29.If the master brake cylinder 10 is actuated by the electric motor 8, the electric motor 8 acts on the hydraulic pistons 11 via the gear element 13, the anti-rotation element 19, the thrust body 26, and the coupling element 27. If the master brake cylinder 10 is actuated by actuating the brake pedal, the brake pedal acts on the hydraulic pistons 11 via the input rod 24, the pressure force transmitter 20, and the coupling element 27.

[0034] The actuating device 1 also has a sensor 30. The sensor 30 is designed to monitor a sliding position of the pressure force transmitter 20 as well as a sliding position of the transmission element 13. The structure of the sensor 30 is explained in more detail below with reference to Figures 3, 4, and 5. Figures 3 and 4 each show a perspective view of the sensor 30. Figure 5 shows the sensor 30 together with other elements of the actuating device 1.

[0035] The sensor 30 has a support element 31. The support element 31 is made of a plastic material. A first sensor part 32 and a second sensor part 33 are slidably mounted on the support element 31. As can be seen from the figures, the sensor parts 32 and 33 are arranged one behind the other in the sliding direction.

[0036] According to the exemplary embodiment illustrated in the figures, the support element 31 is frame-shaped, such that the support element 31 has a frame opening 34. The support element 31 has two first legs 35 aligned parallel to one another and two second legs 36 aligned parallel to one another, wherein the second legs 36 are aligned perpendicular to the first legs 35. The first legs 35 are longer than the second legs 36, such that the support element 31 is elongated overall. The legs 35 and 36 together form or define the frame opening 34. The sensor parts 32 and 33 are slidably mounted in the frame opening 34, such that the sensor parts 32 and 33 are protected by the support element 31. Two metallic guide rods 37 are fastened to the support element 31. The guide rods 37 extend through the frame opening 34 and are aligned parallel to the first legs 35.As can be seen from the figures, the sensor parts 32 and 33 are mounted by the guide rods 37. For this purpose, the sensor parts 32 and 33 each have two openings and are plugged or pushed onto the guide rods 37.

[0037] The sensor 30 is designed as an inductive sensor 30 and, for this purpose, has an elongated printed circuit board 38 on which a coil arrangement 40 (only indicated in the figures) with at least one receiver coil 41 is formed. In the present case, the coil arrangement 40 has a transmitter coil and two receiver coils 41. The coils of the coil arrangement 40 are designed as conductor tracks on the printed circuit board 38. The printed circuit board 38 is fastened to the carrier element 31, in this case by two fastening means 39. The printed circuit board 38 is arranged such that it covers or closes the frame opening 34. The printed circuit board 38 also has a contacting device with a plurality of electrically conductive printed circuit boards 42. The printed circuit boards 42 are arranged on a side of the printed circuit board 38 facing away from the sensor parts 32 and 33.In this case, six circuit boards 42 are provided, with the circuit boards 42 arranged one behind the other in the sliding direction of the sensor parts 32 and 33. Each of the coils is electrically connected to two other circuit boards 42.

[0038] The sensor parts 32 and 33 each have a base body 43 and 44 made of plastic, respectively. On a side facing the circuit board 38, the base bodies 43 and 44 each have an electrically conductive material. The sensor parts 32 and 33 are arranged such that an electrical voltage of the receiver coil 41 can be influenced or is influenced by a sliding position of the sensor parts 32 and 33.

[0039] To monitor the sliding position of the pressure force transmitter 20 and the transmission element 13, the sensor parts 32 and 33 are operatively connected to the pressure force transmitter 20 and the transmission element 13, respectively. This is explained in more detail below with reference to Figure 5. A first driver element 45 attached to the pressure force transmitter 20 is operatively connected to the first sensor part 32 by a first positive connection 46 such that the first sensor part 32 can be moved along with the pressure force transmitter 20. In the present case, the first driver element 45 is formed integrally with the pressure cap 23. The first positive connection 46 is formed in that the first driver element 45 is inserted into a fork-shaped holding structure 47 of the first sensor part 32. The first driver element 45 and the holding structure 47 are shaped such that the holding structure 47 exerts a clamping force on the first driver element 45.The clamping force holds the first driver element 45 in the holding structure 47. However, with a sufficiently large force, the first driver element 45 can be pulled out of the holding structure 47 in order to release the positive connection 46. The first positive connection 46 is therefore designed as a releasable clamping connection 46. A second driver element 48 fastened to the gear element 13 is operatively connected to the second sensor part 33 by a second positive connection 49 such that the second sensor part 33 can be displaced along with the gear element 13. In the present case, the second driver element 48 is formed integrally with the anti-rotation element 19, so that the second driver element 48 is indirectly fastened to the gear element 13. The gear element 13 itself is not shown in Figure 5 for reasons of clarity.The second positive connection 49 is formed by the second driver element 48 being inserted into a fork-shaped holding structure 50 of the second sensor part 33. The second driver element 48 and the holding structure 50 are shaped such that the holding structure 50 exerts a clamping force on the second driver element 48. The clamping force holds the second driver element 48 in the holding structure 50. However, with a sufficiently large force, the second driver element 48 can be pulled out of the holding structure 50 in order to release the positive connection 49. The second positive connection 49 is therefore designed as a releasable clamping connection 49. According to a further exemplary embodiment, the first and / or the second positive connection 46, 49 are preferably designed as a releasable snap-in connection.

[0040] The arrangement of the sensor 30 on the housing 3 is explained in more detail below with reference to Figures 6 and 7. Figure 6 shows a perspective view of the housing 3. Figure 7 shows a further perspective view of the actuating device 1, wherein the control unit 9 is shown semi-transparent in Figure 7. As can be seen from Figure 6, the casing wall 4 has an opening 51. The opening 51 is designed to match the shape of the sensor 30 or the carrier element 31 in such a way that the carrier element 31 can be inserted into the opening 51 at least substantially without play. If the sensor 30 is inserted into the opening 51 as shown in Figure 7 and is thus installed as intended in the actuating device 1, the sensor parts 32 and 33 face the housing interior 5 of the housing 3. In particular, the holding structures 47 and 50 protrude into the housing interior 5.The sensor 30 is fastened to the housing 3 by two fastening means 52, here designed as screws 52. As can be seen from Figure 7, the control unit 9, when the actuating device 1 is assembled as intended, is arranged such that it covers the sensor 30. A casing wall 53 of a control unit housing 54 of the control unit 9 has an opening (not visible in Figure 7) in which the sensor 30 is arranged. The circuit board 38 thus faces directly towards the interior of the control unit housing 54. The control unit 9 is electrically connected to the circuit board 38 by the contact plates 42. For this purpose, the control unit 9 has a number of electrically conductive contact springs corresponding to the number of contact plates 42, whereby the contact springs are not visible in the figures. Each of the contact springs is in touching contact with a different one of the contact plates 42.

Claims

Claims 1. Actuating device for a brake system comprising an actuated master brake cylinder (10), a transmission device (12) comprising a slidably mounted transmission element (13), an electric motor (8) for driving the transmission device (12), a slidably mounted pressure force transmitter (20) connected to an input rod (24) such that the pressure force transmitter (20) is displaceable by the input rod (24), wherein the master brake cylinder (10) can be actuated both by a displacement of the transmission element (13) and by a displacement of the pressure force transmitter (20), and a sensor (30) comprising a first sensor part (32) displaceable with the pressure force transmitter (20) and a second sensor part (33) displaceable with the transmission element (13), characterized in that the first and second sensor parts (32,33) are slidably mounted on a common support element (31) of the sensor (30).

2. Actuating device according to one of the preceding claims, characterized in that the carrier element (31) is frame-shaped, and that the first and second sensor parts (32, 33) are slidably mounted in a frame opening (34) of the carrier element (31).

3. Actuating device according to one of the preceding claims, characterized in that at least one guide rod (37) is attached to the support element (31), and that the first and the second sensor part (32, 33) are slidably mounted by the guide rod (37).

4. Actuating device according to one of the preceding claims, characterized in that the first and the second sensor part (32, 33) are mounted one behind the other in the sliding direction on the carrier element (31).

5. Actuating device according to one of the preceding claims, characterized in that the actuating device (1) has a housing (3) in which the gear element (13) and the pressure force transmitter (20) are at least partially arranged, and that the sensor (30) is attached to the housing (3) in a particularly detachable manner.

6. Actuating device according to claim 5, characterized in that the sensor (30) is inserted into an opening (51) in a shell wall (4) of the housing (3).

7. Actuating device according to one of the preceding claims, characterized in that a first drive element (45) is attached to the pressure force transmitter (20), wherein the first drive element (45) is connected to the first sensor part (32) by a positive locking connection (46), and / or that a second drive element (48) is attached to the gear element (13), wherein the second drive element (48) is connected to the second sensor part (33) by a positive locking connection (49).

8. Actuating device according to claim 7, characterized in that the first drive element (45) cooperates with a fork-shaped retaining structure (47) of the first sensor part (32) to form the positive locking connection (46), and / or that the second drive element (48) cooperates with a fork-shaped retaining structure (50) of the second sensor part (33) to form the positive locking connection (49).

9. Actuating device according to one of claims 7 and 8, characterized in that the first drive element (45) is attached to the first sensor part (32) by a detachable snap connection or a detachable clamping connection (46) and / or that the second drive element (48) is attached to the second sensor part (33) by a detachable snap connection or a detachable clamping connection (49).

10. Actuating device according to one of the preceding claims, characterized in that the sensor (30) has a circuit board (38) attached to the carrier element (31), on which at least one receiver coil (41) is formed.

11. Actuating device according to claim 12, characterized in that the circuit board (38) has at least one electrically conductive contact plate (42) for electrical contact with a control unit (9).

12. Actuating device according to one of claims 10 and 11, characterized in that the first sensor part (32) has an electrically conductive material and is arranged such that an electrical voltage of the receiver coil (41) can be influenced by a sliding position of the first sensor part (32), and / or that the second sensor part (33) has an electrically conductive material and is arranged such that the electrical voltage of the receiver coil (41) can be influenced by a sliding position of the second sensor part (33).

13. Actuating device according to one of the preceding claims, characterized by a control unit (9) which is arranged on the housing (3) of the actuating device (1) such that the control unit (9) covers the sensor (30).

14. Actuating device according to claim 13, characterized in that the control unit (9) has a control unit housing (54), and that the sensor (30) is arranged in an opening in a shell wall of the control unit housing (54).

Images