Brake booster system, braking system and vehicle

Abstract

Brake booster device (1), comprising at least one piston (22, 23) deflectable in the axial direction and at least one spring element (7, 11, 16) which is designed to exert a restoring force on the piston (22, 23), wherein the brake booster device (1) has at least one magnet (13) which is designed to exert a magnetic restoring force on the piston (22, 23)

Description

[0001] The present invention relates to a brake booster device, a braking system and a vehicle. State of the art

[0002] DE 10 2014 215 790 A1 shows a storage chamber valve device.

[0003] DE 199 05 790 A1 concerns a piston pump. Disclosure of the invention

[0004] The core of the invention in the brake booster device, comprising at least one piston deflectable in the axial direction and at least one spring element configured to exert a restoring force on the piston, consists in the fact that the brake booster device has at least one magnet configured to exert a magnetic restoring force on the piston.

[0005] The background of the invention is that the magnet serves to improve the restoring capability of the brake booster device, particularly in the event of a reduced restoring force due to increased viscosity of the brake fluid at low temperatures or in the event of a return mechanism failure. This allows the use of a spring element with lower spring force and / or a drive with higher mechanical resistance. The brake booster device thus operates more efficiently because less counterpressure acts on the piston during braking. This is achieved by a high restoring force at short piston travels and, at the same time, a low restoring force at long piston travels.

[0006] Further advantageous embodiments of the present invention are the subject of the subclaims.

[0007] According to an advantageous embodiment, the brake booster device has a neutral position, wherein the magnetic restoring force on the piston is greatest in the neutral position, in particular wherein the magnet is spaced apart from a housing of the brake booster device or from deflectable parts of the brake booster device connected to the piston in the neutral position. As a result, the magnetic force acts more strongly in the region of the neutral position, so that the restoring force that must be overcome in the operating range of the brake can be reduced. Advantageously, the magnet acts without contact and is therefore wear-free.

[0008] It is advantageous if the magnet(s) are immobile in the axial direction. The magnet(s) are thus designed to attract the axially displaceable piston or a ferromagnetic component connected to the piston, such as an anti-rotation plate. The magnets can be arranged so that they can rotate in the radial direction.

[0009] Alternatively or additionally, it is advantageous if the magnet(s) are movable in the axial direction, particularly if the magnet(s) are at least indirectly connected to the piston. This allows, for example, two magnets with opposite polarity to be used, which attract each other and amplify the magnetic restoring force. One magnet is movable in the axial direction, while the other magnet is immobile in the axial direction.

[0010] Furthermore, it is advantageous if the brake booster device has a plurality of magnets arranged distributed around an axis of the piston, in particular wherein the magnets are arranged along a radius, in particular wherein the magnets are evenly distributed in the circumferential direction. Thus, a uniform magnetic restoring force can be exerted on the piston.

[0011] According to an advantageous embodiment, the brake booster device has a gear mechanism, wherein the magnet is connected to the gear mechanism, in particular wherein the magnet is arranged on a surface of the gear mechanism facing the piston. This allows the brake booster device to be designed compactly.

[0012] According to a further advantageous embodiment, the brake booster device comprises a housing, wherein the housing has a housing portion, in particular a projection, which exerts a magnetic attraction force on the piston, in particular wherein the housing is ferromagnetic. As a result, no additional second magnet is required, so that the brake booster device can be implemented cost-effectively.

[0013] It is advantageous if a magnet is arranged on the housing section. This allows, for example, two magnets with opposite polarity to be used, which attract each other and amplify the magnetic restoring force. Alternatively, the magnet acts on a ferromagnetic component connected to the piston, such as an anti-rotation plate.

[0014] Alternatively or additionally, a magnet is at least indirectly connected to the piston, in particular, a magnet is arranged on a bushing by means of which an anti-rotation plate connected to the piston is guided on a tie rod. This allows, for example, two magnets with opposite polarity to be used, which attract each other and amplify the magnetic restoring force.

[0015] Furthermore, it is advantageous if the magnet or magnets are spaced apart from a sensor and / or an electric motor and / or a control unit of the brake booster device. Thus, the sensor and / or the electric motor and / or the control unit are protected from the magnetic field of the magnets. Additionally, a magnetic shield, such as a housing, can be provided between the magnets and the sensor and / or the electric motor and / or the control unit.

[0016] According to a further advantageous embodiment, the brake booster device has an electric motor and a mechanism by means of which the piston can be deflected and / or reset.

[0017] The essence of the invention in the braking system is that the braking system has a brake booster device as described above or according to one of the claims relating to the brake booster device.

[0018] The background of the invention is that the braking system can be designed compactly and efficiently. Furthermore, the availability of the braking system is improved.

[0019] The essence of the invention in the vehicle is that the vehicle has a braking system as described above or according to the claim relating to the braking system.

[0020] The above embodiments and developments can be combined with one another as desired, where appropriate. Further possible embodiments, developments, and implementations of the invention also include combinations of features of the invention described above or below with reference to the exemplary embodiments that were not explicitly mentioned. In particular, those skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention. Short description of the drawing

[0021] In the following section, the invention is explained using exemplary embodiments, from which further inventive features may arise, but to which the scope of the invention is not limited. The exemplary embodiments are illustrated in the drawings.

[0022] They show: Fig. 1 a schematic representation of a brake booster device 1 according to a first embodiment of the present invention, Fig. 2 a schematic representation of a brake booster device 1a according to a second embodiment of the present invention and Fig. 3 a magnetic restoring force on a piston (22, 23) of the brake booster device (1, 1a) according to the invention as a function of a distance d of the piston (22, 23) to a neutral position of the piston (22, 23).

[0023] The Fig. The brake booster device 1 shown in Figure 1 comprises an electric motor 6, a mechanism with a gear 5, a spindle 4, a third spring element 7 and a spindle nut 3, as well as a master brake cylinder 10.

[0024] In the exemplary embodiments shown in the figures, the master brake cylinder 10 has a first chamber 17 and a second chamber 12 and is thus designed as a tandem master brake cylinder. Alternatively, the master brake cylinder 10 can also have only a single chamber in which a single piston with a single spring element is arranged.

[0025] The master brake cylinder 10 has a first piston 22 and a second piston 23, wherein the first piston 22 is arranged in the first chamber 17 and the second piston 23 is arranged in the second chamber 12. The second piston 23 can be deflected by means of the first piston 22. The first piston 22 is connected to a first spring element 16 and the second piston 23 is connected to a second spring element 11. The respective spring element (11, 16) is designed to exert a restoring force on the respective piston (22, 23). The spring elements (7, 11, 16) are designed, for example, as coil springs.

[0026] The master brake cylinder 10 is connected to a brake circuit system not shown in the figure. Preferably, each chamber (12, 17) has a respective supply line connected to a respective brake circuit.

[0027] The brake booster device 1 can be actuated by means of an actuating device 2, which can be connected, for example, to a brake pedal. The actuating device 2 is arranged such that a driver braking force applied to the actuating device 2 deflects the spindle 4. The spindle 4 is connected to a first piston 22 and deflects it.

[0028] The brake booster device 1 has a sensor 26, in particular a differential travel sensor, for detecting the deflection of the spindle 4. The sensor 26 is designed, for example, as a magnetic sensor, in particular as a Hall sensor.

[0029] The actuation can be an adjustment or movement of a mechanism, whereby a braking effect on a friction brake can be activated or released, for example the master brake cylinder 10 of the brake booster device 1 can be reset from a braking position in which a friction brake is active to a neutral position.

[0030] To boost the brake force, the electric motor 6 is configured to drive the spindle nut 3 via the gear 5. The spindle nut 3 is connected to the spindle 4 and configured to amplify the deflection of the spindle 4. An anti-rotation plate 20 is connected to the spindle 4, which prevents the spindle 4 from rotating with the spindle nut 3. For this purpose, the anti-rotation plate 20 is connected to tie rods 21 via bushings 19. When the spindle nut 3 rotates, the anti-rotation plate 20 is guided by the tie rods 21, so that the spindle 4 is deflected and brake pressure is built up in the master brake cylinder 10.

[0031] The anti-rotation plate 20 is made of a ferromagnetic material, for example, steel. The anti-rotation plate 20 extends transversely to a rotational axis of the spindle 4 from the spindle 4 to the tie rods 21. The anti-rotation plate 20 at least partially surrounds the spindle 4. For example, the anti-rotation plate 20 is plate-shaped, with a plate base of the anti-rotation plate 20 being connected to the spindle 4 and a plate edge being connected to the tie rods 21.

[0032] The spring elements (7, 11, 16) exert a restoring force on the pistons (22, 23). This restoring force is limited in a position range of the pistons (22, 23) just before the neutral position, in which no braking force acts on the brake circuit system. Therefore, spring elements (7, 11, 16) with a high spring force should be selected, particularly at low temperatures, which cause increased viscosity of the brake fluid.

[0033] To locally amplify the restoring force, at least two magnets 13, in particular permanent magnets, are arranged on a surface of the gear 5 facing the anti-rotation plate 20. The magnets 13 are arranged substantially uniformly distributed in the circumferential direction around an axis of the piston (22, 23) on the same radius. An air gap is provided between the gear 5 and the anti-rotation plate 20, so that the magnets 13 attract the anti-rotation plate 20, but the gear 5, or the magnets 13, do not touch the anti-rotation plate 20.

[0034] The pistons (22, 23) in the master brake cylinder 10 can be reset by means of the spring force of the spring elements (7, 11, 16) and the magnetic force of the magnets 13 acting on the ferromagnetic anti-rotation plate 20. The spring force acts over the entire adjustment range of the pistons (22, 23). The magnets 13 have the strongest effect in a position range of the pistons (22, 23) just before the neutral position. The restoring force acting on the pistons (22, 23) is therefore the sum of the spring force of the first spring element 16, the spring force of the second spring element 11, the spring force of the third spring element 7, and the magnetic force of the magnets 13.

[0035] The magnets 13 are arranged at a distance from the sensor 26 and / or the motor 6 and / or a control unit (not shown) of the brake booster device 1. Additionally, a magnetic shield can be arranged between the magnets 13 and the sensor 26 and / or the motor 6 and / or the control unit.

[0036] The spindle 4, the spindle nut 3, the gear 5, the third spring element 7, the sensor 26 and the anti-twist plate 20 are arranged in a housing 18.

[0037] The Fig. The second embodiment of the brake booster device 1a shown in Fig. 2 differs from the first embodiment in the arrangement of the magnets 13a.

[0038] The magnets 13a are arranged in the bushings 19 between the anti-rotation plate 20 and the tie rods 21. For example, the bushings 19 are made of plastic, with the magnets 13a cast into the plastic. At least two magnets 13a are arranged evenly spaced from one another in the circumferential direction. Preferably, a respective magnet 13a is arranged in each bushing 19.

[0039] The housing 18 is at least partially ferromagnetic and has a counter surface, in particular a projection, for each magnet 13a. A magnetic attraction force acts between the magnets 13a and the counter surfaces, which acts as a restoring force on the pistons (22, 23). A further magnet with opposite polarity to the respective magnet can be arranged on each counter surface, which amplifies the magnetic attraction force acting on the anti-rotation plate 20.

[0040] In Fig.Figure 3 shows a magnetic restoring force acting on a piston (22, 23) of the brake booster device (1, 1a) according to the invention as a function of a distance d of the piston (22, 23) from a neutral position of the piston (22, 23). At a minimum distance d1, which corresponds to the neutral position, the maximum magnetic restoring force F acts on the piston (22, 23). This force F decreases with increasing distance, with the curve flattening out up to a maximum distance d2. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 215 790 A1

[0002] DE 199 05 790 A1

[0003]

Claims

[1] Brake booster device (1), comprising at least one piston (22, 23) which can be deflected in the axial direction and at least one spring element (7, 11, 16) which is designed to exert a restoring force on the piston (22, 23), characterized by that the brake booster device (1) has at least one magnet (13, 13a) which is designed to exert a magnetic restoring force on the piston (22, 23). [2] Brake booster device (1) according to claim 1, characterized by that the brake booster device (1) has a neutral position, wherein the magnetic restoring force on the piston (22, 23) is greatest in the neutral position, in particular wherein the magnet (13, 13a) in the neutral position is spaced from a housing (18) of the brake booster device (1) or is spaced from deflectable parts of the brake booster device (1) connected to the piston (22, 23). [3] Brake booster device (1) according to claim 1 or 2, characterized by , that the magnet (13, 13a) or the magnets (13, 13a) are immobile in the axial direction and / or that the magnet (13, 13a) or the magnets (13, 13a) are movable in the axial direction, in particular wherein the magnet (13, 13a) or the magnets (13, 13a) are at least indirectly connected to the piston (22, 23). [4] Brake booster device (1) according to one of the preceding claims, characterized by that the brake booster device (1) has a plurality of magnets (13) which are arranged distributed around an axis of the piston (22, 23), in particular wherein the magnets (13) are arranged on a radius, in particular wherein the magnets (13, 13a) are arranged uniformly distributed in the circumferential direction. [5] Brake booster device (1) according to one of the preceding claims, characterized bythat the brake booster device (1) has a gear (5), wherein the magnet (13) is connected to the gear (5), in particular wherein the magnet is arranged on a surface of the gear (5) facing the piston (22, 23). [6] Brake booster device (1) according to one of the preceding claims, characterized by that the brake booster device (1) has a housing (18), wherein the housing (18) has a housing section, in particular a projection, which exerts a magnetic attractive force on the piston (22, 23), in particular wherein the housing (18) is ferromagnetic. [7] Brake booster device (1) according to claim 6, characterized by , that a magnet is arranged on the housing section, and / or that a magnet (13a) is at least indirectly connected to the piston (22, 23), in particular wherein a magnet (13a) is arranged on a bushing (19) by means of which an anti-rotation plate (20) connected to the piston (22, 23) is guided on a tie rod (21). [8] Brake booster device (1) according to one of the preceding claims, characterized by that the magnet (13, 13a) or the magnets (13, 13a) are spaced from a sensor (26) and / or an electric motor (6) and / or a control unit of the brake booster device (1). [9] Brake booster device (1) according to one of the preceding claims, characterized by that the brake booster device (1) has an electric motor (6) and a mechanism by means of which the piston (22, 23) can be deflected and / or reset. [10] Brake system comprising a brake booster device (1) according to one of the preceding claims. [11] A vehicle comprising a braking system according to claim 10.

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