CN113677574A

CN113677574A - Actuating device for a brake system

Info

Publication number: CN113677574A
Application number: CN202080026749.7A
Authority: CN
Inventors: W·纳格尔; E·科尔特斯瓜施; M·奥塞斯
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-04-01
Filing date: 2020-03-24
Publication date: 2021-11-19
Anticipated expiration: 2040-03-24
Also published as: DE102019204554A1; WO2020200915A1; JP7235429B2; CN113677574B; JP2022525800A

Abstract

The invention relates to an actuating device (1) for a brake system, comprising an entry lever (10) which can be displaced by a brake pedal in an actuating direction (4); with a displacement sensor (11) which has a measured value transmitter (14) and a receiver (12) and which is designed to detect a displacement position of the entry lever (10); and with a braking force generator (5) having a spindle drive (6) with a spindle nut (7) and a spindle (8), wherein the spindle nut (7) is mounted so as to be rotatable about a rotational axis (46) extending in a steering direction (4), and the spindle (8) can be displaced in the axial direction by rotation of the spindle nut (7), and the braking force generator is designed to: displacing the spindle (8) in an axial direction for actuating a master brake cylinder (2) of the brake system as a function of the detected displacement position, wherein the inlet rod (10) can be displaced in the axial direction relative to the spindle (8), and wherein the actuating device (1) has a pedal travel simulator (18) which can be actuated by means of the inlet rod (10). A bearing (19) for transmitting axial forces is provided, which is held axially between the spindle nut (7) on the one hand and the pedal travel simulator (18) on the other hand.

Description

Actuating device for a brake system

Technical Field

The invention relates to an actuating device for a brake system, comprising an entry lever which can be displaced in an actuating direction by a brake pedal; with a displacement sensor having a measured value transmitter and a receiver and being configured to acquire a displacement position of the entry rod; and with a braking force generator having a screw drive with a screw nut and with a screw, wherein the screw nut is supported rotatably about a rotational axis extending in the operating direction and the screw can be displaced axially by rotation of the screw nut, and the braking force generator is configured for: displacing the threaded spindle in an axial direction for actuating a master brake cylinder of the brake system as a function of the detected displacement position, wherein the inlet rod is displaceable in the axial direction relative to the threaded spindle, and wherein the actuating device has a pedal travel simulator which can be actuated by the inlet rod.

Background

Hydraulic brake systems for motor vehicles usually have at least one wheel brake system associated with a wheel. The brake system also has a master cylinder which is fluidically connected to the wheel brake cylinders of the wheel brake device, so that by an axial displacement of a hydraulic piston mounted in the master cylinder in the actuating direction, brake fluid is displaced into the wheel brake cylinders, and thus a deceleration torque is generated by the wheel brake device. An actuating device is provided for actuating the master brake cylinder, i.e. for displacing the hydraulic piston.

An actuating device for a brake system is known, for example, from the publication DE 102015217522 a 1. The actuating device has a braking force generator with a spindle drive. The spindle drive comprises a spindle nut which is mounted so as to be rotatable about a rotational axis extending in the actuating direction, and a spindle which can be displaced axially by rotation of the spindle nut. Furthermore, previously known actuating devices have an entry lever which can be displaced by the brake pedal in the actuating direction. In this case, the inlet rod can be displaced in the axial direction relative to the threaded spindle. Furthermore, the actuating device has a displacement sensor which has a measured value transmitter and a receiver and which is designed to detect a displacement position of the entry lever. Finally, the braking force generator is configured to: displacing the threaded spindle in an axial direction for actuating the master brake cylinder as a function of the acquired displacement position. In the case of previously known actuating devices, the inlet rod is directly mechanically coupled to the hydraulic piston at least when the master brake cylinder is actuated, so that an axial force can be transmitted directly to the hydraulic piston by displacement of the inlet rod. The brake equipment with the previously known operating device is therefore a service brake.

Furthermore, dynamic brakes are known from the prior art. The power brake is characterized in that the inlet rod of the actuating device and the hydraulic piston of the master brake cylinder are mechanically decoupled during normal operation of the actuating device for actuating the master brake cylinder. This means that there is at least no rigid mechanical coupling between the inlet rod and the hydraulic piston. In order to generate the desired reaction force in the case of a power brake, which counteracts the displacement of the entry lever in the actuation direction and which can be sensed by the user of the actuation device, the power brake usually has a pedal travel simulator which can be actuated by the entry lever.

Disclosure of Invention

The inventive actuating device for a brake system ensures a low-friction and therefore low-wear support or bearing for the end of the pedal travel simulator facing away from the inlet lever. In particular, the following advantages are furthermore obtained: the actuation device ensures a Push-Through-function (durchreten-function) of the brake system, which is designed as a power brake. Here, the penetrating function is to be understood as: the master brake cylinder can be actuated directly by displacement of the inlet rod in the actuation direction in the event of failure of the brake force generator, in particular of an electric motor of the brake force generator, i.e. in this case a rigid mechanical coupling is present or produced between the inlet rod and the hydraulic piston. This increases the safety when operating a vehicle having the actuating device or having a brake system with the actuating device. According to the invention, the actuating device has a bearing for transmitting axial forces, which is held axially between the spindle nut on the one hand and the pedal travel simulator on the other hand. The bearing is therefore designed to transmit axial forces, that is to say forces acting in or counter to the actuating direction, from the pedal travel simulator to the spindle nut or from the spindle nut to the pedal travel simulator. Furthermore, the bearing is designed in such a way that it enables a low-friction rotation of the spindle nut relative to the pedal travel simulator. In order to ensure the through-type function, the spindle nut can be displaced axially in the actuating direction at least in the event of a failure of the brake force generator, so that the spindle nut is displaced in the actuating direction by a displacement of the inlet rod in the actuating direction in the event of a failure of the brake force generator, and the master brake cylinder is actuated by a displacement of the spindle nut.

According to a preferred embodiment, provision is made for: the bearing is designed as a rolling bearing, in particular a ball bearing, or as a sliding bearing. These bearing types ensure, on the one hand, the transmission of axial forces from the pedal travel simulator to the spindle nut or from the spindle nut to the pedal travel simulator, and on the other hand enable a rotation of the spindle nut about the axis of rotation relative to the pedal travel simulator. Here, a rolling bearing is to be understood as a bearing having rolling elements for reducing frictional resistance. The following advantages are obtained if the bearing is designed as a rolling bearing: the screw nut can be rotated particularly low-friction. It is particularly preferred that the rolling elements are balls, so that the rolling bearing is designed as a ball bearing. As an alternative to being designed as a rolling bearing, the bearing is designed as a plain bearing. Here, a plain bearing is to be understood as a bearing: in which the frictional resistance is at least substantially reduced by lubrication of the bearing. The following advantages are obtained if the bearing is designed as a plain bearing: particularly high axial forces can be transmitted through the bearing without damaging the bearing.

According to a preferred embodiment, provision is made for: the bearing, which is designed as a rolling bearing, has a first bearing ring and a second bearing ring, wherein the bearing rings are rotatable relative to one another about an axis of rotation, and wherein the rolling bodies of the bearing are arranged radially or axially between the bearing rings. In particular, the rolling bodies are arranged radially between the bearing rings. According to this embodiment, the bearing rings are arranged concentrically to one another, wherein the outer bearing ring of the bearing rings has a larger diameter than the inner bearing ring of the bearing rings. As an alternative to this, the rolling bodies are arranged axially between the bearing rings. According to this embodiment, the two bearing rings are arranged one behind the other, as seen in the actuating direction. The following advantages are thereby obtained: the bearing is designed to transmit particularly high axial forces.

According to a preferred embodiment, provision is made for: the entry rod extends coaxially through at least a section of the pedal stroke simulator. This results in a space-saving arrangement of the pedal travel simulator.

Preferably, the pedal travel simulator has a first spring device, in particular a helical spring and/or an elastomer spring.

Therefore, the pedal stroke simulator is configured to be elastically deformable when the entry lever is displaced in the manipulation direction. The present invention relates to a particularly simple design of the pedal travel simulator in terms of construction. Preferably, the pedal travel simulator is supported at the entry lever by means of the first spring device. The end of the first spring device facing away from the master brake cylinder therefore bears axially against the end of the inlet rod facing the master brake cylinder. Preferably, the first spring device has at least one helical spring. In particular, the coil spring has a small spring constant, so that a reaction force of at most 90N can be provided by the coil spring. In particular, alternatively or additionally, the first spring device has an elastomer spring. The elastic body spring has a larger spring constant than the coil spring and is directly supported at the coil spring in an axial direction. The damping effect of the first spring device is thus increased by providing the elastomer spring as an alternative or in addition to providing it only in comparison with providing it.

Preferably, the pedal travel simulator has a second spring device, in particular at least one elastomer spring. By providing the second spring device, a more precise adaptation of the displacement position/reaction force characteristic curve can be achieved. Preferably, the second spring means has a spring constant greater than that of the first spring means. Preferably, the second spring device has at least one elastomer spring for this purpose. In particular, the second spring device is configured such that at least one reaction force between 90N and 1000N can be provided by the second spring device depending on the degree of elastic deformation of the second spring device.

According to a preferred embodiment, the pedal travel simulator has a third spring device, which in particular has at least one leg spring. The accuracy of the adaptation of the displacement position-reaction force characteristic curve is further increased by the provision of the third spring device. In this case, the third spring device preferably has a spring constant which is greater than the spring constant of the second spring device. Preferably, the spring means of the pedal stroke simulator are connected in series. The spring devices are thus arranged such that an axial force can be transmitted by each of the spring devices of the pedal travel simulator directly or indirectly (for example in the case of an intermediate connection of a force-transmitting element such as, for example, a sleeve, a follower or the like) to the further spring devices of the pedal travel simulator.

Preferably, the actuating device has a sleeve-shaped first element which is displaceable in the axial direction relative to the threaded spindle, wherein the element has an axial recess in which the first spring device is arranged, and wherein the actuating device has at least one first unloaded state in which the radial projection of the entry rod has an axial spacing to the rear side of the first element, and a first actuating state in which the radial projection, after compressing the first spring device, bears axially against the rear side of the first element, so that further compression of the first spring device is prevented by the axial abutment. Since the first spring device is arranged in an axial recess of the first element, the end of the first spring device facing the master brake cylinder bears axially against the side of the first element facing away from the master brake cylinder. The maximum permissible extent of the compression of the first spring device is defined by the provision of a first element which is constructed as described above. Thereby, the accuracy of the adaptation of the reaction force is further improved. The sleeve-shaped element is in particular a cylindrical element, which has an axial groove. The housing wall of the element is in particular designed continuously, so that the axial recess is completely enclosed by the housing wall. As an alternative to this, the housing wall has at least one housing wall opening. The radial projection is to be understood as a cross-sectional thickening of the entry rod. The entry lever therefore has a larger cross section in the region of the radial projection than immediately behind the radial projection, as viewed in the actuating direction. The rear side is understood in the scope of the patent application to be the side of the element facing away from the master brake cylinder. An end face is to be understood as meaning the side of the element facing the master brake cylinder.

Preferably, the screw has an axial groove in which either the first spring device or the first spring device and the first element are arranged. By means of such an arrangement of the spring device or the spring device and the first element, a particularly space-saving design of the pedal travel simulator is achieved.

Preferably, the actuating device has a sleeve-shaped second element which is displaceable in the axial direction relative to the first element, through which the entry rod extends coaxially, wherein the second element has a radial projection, against the end side of which the third spring device rests, wherein the second element has a larger cross section than the first element, and wherein the first element has a radial projection, the cross-sectional narrowing of which engages behind the radial projection. By providing a second element configured as described above, it is ensured that: an actuating force exerted by the user on the entry lever, which actuating force acts axially in the actuating direction, can be transmitted or transmitted at least to the third spring device.

Preferably, the actuating device has two guide disks which are displaceable relative to one another in the axial direction, wherein an end face of a first of the guide disks bears axially against a rear face of the second spring device and a rear face of a second of the guide disks bears axially against an end face of the second spring device, wherein at least one of the guide disks has an axial projection which extends in the direction of the other guide disk, and wherein the actuating device has a second unloaded state in which the axial projection of the one guide disk has an axial distance to the other guide disk and a second actuated state in which the axial projection bears axially against the other guide disk after compression of the second spring device, thereby preventing further compression of the second spring means by axial abutment. The maximum permissible compression of the second spring device is therefore predetermined by the provision of the guide disk which is constructed as described above. In this way, the displacement position/reaction force characteristic curve can be specified particularly precisely. Furthermore, plastic deformations of the elastomer spring due to too severe a compression of the elastomer spring are avoided. In particular, the first unloaded state corresponds to the second unloaded state, so that in the unloaded state not only the first spring device but also the second spring device can then be compressed by a displacement of the entry lever in the actuation direction. A guide disk is to be understood as a disk-shaped element, that is to say the following: the radial extension of the element is greater, in particular significantly greater, than its axial extension.

According to a preferred embodiment, provision is made for: the third spring device has a first and a second leg spring, wherein the leg springs are arranged axially spaced apart from one another, and wherein either the second spring device or the second spring device and the guide disk are arranged between the leg springs. Such a design of the second spring device and the third spring device relates on the one hand to a particularly space-saving design of the pedal travel simulator. On the other hand, the configuration or arrangement of the second and third spring devices ensures that: axial forces can be transmitted from the second spring device to the third spring device or from the third spring device to the second spring device.

Preferably, the bearing is axially retained between the screw nut on the one hand and the belleville spring of the third spring means on the other hand. A particularly stable abutting contact between the bearing and the pedal stroke simulator is thereby obtained. According to a preferred embodiment, provision is made for: the belleville springs are arranged and configured to be elastically deformable such that they bear against only one of the bearing rings under an axial load which is less than a threshold load and bear against both of the bearing rings under an axial load which is greater than the threshold load. The bearing is designed as a rolling bearing, the bearing rings of which are arranged concentrically to one another, so that the rolling bodies of the bearing are arranged radially between the bearing rings. Bearings of this type usually have a maximum permissible axial load, wherein the bearing can be damaged by the axial load when the maximum permissible axial load is exceeded. The belleville springs are configured or arranged such that the threshold load is equal to or lower than the maximum allowable axial load. This achieves that the pedal travel simulator bears against the two bearing rings under an axial load that is higher than the maximum permissible axial load, as a result of which damage to the bearings is avoided.

Preferably, the pedal travel simulator is held preloaded between the entry lever on the one hand and a component arranged on the first housing part on the other hand. In this case, the components arranged are arranged either directly next to one another, that is to say directly or not directly next to one another, or, with the interposition of at least one further element, on the first housing part. In particular, the component arranged is the first housing part itself, a further housing part or the master brake cylinder. The advantages resulting from the pretensioning of the pedal travel simulator are as follows: the components of the pedal stroke simulator are held together compactly.

Preferably, the actuating device has a fourth spring device, which is supported on one side on a component arranged on the first housing part and on the other side on the pedal travel simulator for preloading the pedal travel simulator. The pretensioning of the pedal travel simulator is therefore provided at least partially by the fourth spring device. The fourth spring device is also supported at the component arranged or at the pedal travel simulator either directly, i.e., not directly, i.e., in the middle of the connection of at least one further element. Preferably, the fourth spring device has a return spring for the threaded spindle. The component arranged is then, for example, the first housing part itself, a further housing part or the master brake cylinder. For support at the pedal travel simulator, the return spring for the spindle is supported, for example, at a pressure plate coupled to the spindle, wherein the pressure plate is displaceable with the spindle at least in the actuating direction and the spindle is displaceable with the pressure plate at least counter to the actuating direction. Thus, the return spring for the screw is supported at the pedal stroke simulator by means of the pressure plate, the screw nut, and the bearing. Alternatively or additionally, the fourth spring device has a return spring for the hydraulic piston. The return spring is supported on one side within the master brake cylinder on the side of the master brake cylinder facing the inlet rod and on the other side on the side of the hydraulic piston facing away from the inlet rod. Thus, the return spring for the hydraulic piston is supported at the pedal stroke simulator by means of the hydraulic piston, the pressure rod, the screw nut, and the bearing.

Drawings

The invention is explained in more detail below with the aid of the drawings, in which identical and corresponding elements are provided with the same reference numerals in the figures.

Wherein:

fig. 1 shows a first exemplary embodiment of an advantageous actuating device of a brake system; and is

Fig. 2 shows a second exemplary embodiment of the actuating device.

Detailed Description

Fig. 1 shows a longitudinal section through an actuating device 1 of a brake system. The actuating device 1 shown in fig. 1 is a first exemplary embodiment of the actuating device 1. The actuating device 1 is designed to actuate a master brake cylinder 2 of the brake system, i.e. to displace a hydraulic piston 3 supported in the master brake cylinder 2 in an actuating direction 4. The master brake cylinder 2 is fluidically connected to wheel brake cylinders of a wheel brake system, not shown. By displacing the hydraulic piston 3 in an actuating direction 4, hydraulic fluid is displaced from the master brake cylinder 2 into the wheel brake cylinder. A deceleration torque is thus generated by the wheel braking device.

The manipulator 1 has a braking force generator 5. The braking force generator 5 has a screw drive 6. The spindle drive 6 has a spindle nut 7 which can be driven by an electric motor of the braking force generator 5 and is mounted so as to be rotatable about a rotational axis 46 extending in the actuating direction 4. Furthermore, the spindle drive 6 has a spindle 8 arranged in a rotationally fixed and axially displaceable manner, wherein an outer drive of the spindle 8 engages with an inner drive of the spindle nut 7, so that the spindle 8 can be displaced axially by rotation of the spindle nut 7. By displacing the threaded spindle 8 in the axial direction of the actuating direction 4, a pressure rod 9, the end face of which bears against the hydraulic piston 3 at least during actuation of the master brake cylinder 2, is displaced together with the threaded spindle 8.

The actuating device 1 has an entry lever 10 which can be displaced in an actuating direction 4 by a brake pedal, not shown, and can be displaced axially relative to the spindle 8. In order to displace the entry lever 10 in the actuating direction 4, a user of the actuating device 1 actuates the brake pedal, as a result of which an axial force or actuating force acting in the actuating direction 4 is transmitted to the entry lever 10. Furthermore, the actuating device 1 has a displacement sensor 11, which is designed to detect a displacement position of the entry lever 10. The displacement sensor 11 has a receiver 12, which is arranged on a first, fixed housing part 13 of the actuating device 1. Furthermore, the displacement sensor 11 has a measured value transmitter 14, which is arranged on a second housing part 15 of the actuating device 1, which is coupled to the entry lever 10. The two housing parts 13 and 15 are arranged concentrically to one another, the second housing part 15 being guided radially in the first housing part 13. The second housing part 15 has a radial projection 16 at its rear end, as viewed in the actuating direction 4, which engages behind a cross-sectional constriction 17 of the front end, as viewed in the actuating direction 4, of the first housing part 13. The maximum permissible displacement of the entry lever 10 opposite the actuating direction 4 is defined by the radial projection 16 and the cross-sectional constriction 17. In this case, the entry lever 10 cannot be displaced or cannot be displaced further counter to the actuating direction 4 when the radial projection 16 axially abuts against the cross-sectional constriction 17.

Furthermore, the actuating device 1 has a pedal travel simulator 18. Here, the pedal travel simulator 18 is to be understood as the following: the device is designed to provide a force, i.e. a reaction force, acting on the entry lever 10 counter to the actuating direction 4. Since the entry lever 10 is coupled to the brake pedal, the reaction force is transmitted to the brake pedal via the entry lever 10 and is thus perceived by the user of the actuating device 1. In order to provide the reaction force, the pedal travel simulator 18 can be actuated via the entry lever 10.

Furthermore, the actuating device 1 has a bearing 19 which transmits axial forces and is held axially between the spindle nut 7 on the one hand and the pedal travel simulator 18 on the other hand. In this case, the bearing 19 enables the spindle nut 7 to be rotated relative to the pedal travel simulator 18. For this purpose, the bearing 19 has two bearing rings 20 and 21, which are rotatable relative to one another about a rotational axis 46. Here, the bearing 19 is a ball bearing 19. The balls of the ball bearing 19 are arranged radially between the bearing rings 20 and 21. The bearing rings 20 and 21 are therefore an outer bearing ring 20 and an inner bearing ring 21, wherein the outer bearing ring 20 has a larger diameter than the inner bearing ring 21 and the bearing rings 20 and 21 are arranged concentrically to one another. According to the illustration from fig. 1, the spindle nut 7 bears axially against the outer bearing ring 20. The pedal travel simulator 18 bears axially against an inner bearing ring 21 of the bearing 19. As an alternative to this, the spindle nut 7 bears axially against the inner bearing ring 21 and the pedal travel simulator 18 bears axially against the outer bearing ring 20.

The pedal stroke simulator 18 has a first spring device 22, a second spring device 23 and a third spring device 24. The spring means 22, 23 and 24 are connected in series. The first spring device 22 has a helical spring 25 according to the exemplary embodiment from fig. 1. The coil spring 25 has a small spring constant. The helical spring 25 is therefore designed to provide only a small reaction force, in particular a reaction force of less than 90N. The end of first spring device 22 or of helical spring 25 facing away from master brake cylinder 2 bears axially at least indirectly against the end of inlet rod 10 facing master brake cylinder 2. Thus, the pedal travel simulator 18 is supported at the entry lever 10 by means of the first spring device 22. The second spring device 23 has an elastomer spring 26. The elastomeric spring 26 is configured to provide a reaction force between 90N and 1000N. For this purpose, the second spring device 23 or the elastomer spring 26 has a greater spring constant than the first spring device 22. The third spring arrangement 24 here has a first leg spring 27 and a second leg spring 28. The belleville springs 27 and 28 are each configured to provide a reaction force greater than 1000N. For this purpose, the third spring device 24 has a greater spring constant than the second spring device 23 or the first spring device 22.

Furthermore, the actuating device 1 has a sleeve-shaped first element 29. The first element 29 has an axial groove 44, in which the first spring device 22 or the helical spring 25 is arranged. The end of first spring device 22 or of coil spring 25 facing master brake cylinder 2 abuts axially within axial recess 44 against the side of first element 29 facing away from master brake cylinder 2. In this case, the first element 29 can be displaced axially relative to the threaded spindle 8 and is mounted in an axial groove 45 of the threaded spindle 8.

Here, an intake piston 30 is arranged between the intake rod 10 and the helical spring 25. The inlet piston 30 is mounted in an axially displaceable manner within the first element 29 and has a radial projection 31. The intake piston 30 is mechanically rigidly coupled to the intake rod 10 at least in the axial direction. The following is therefore assumed: the intake piston 30 is a component of the intake rod 10. Thus, the radial projection 31 is also an integral part of the entry lever 10. According to the illustration from fig. 1, the radial projection 31 has an axial distance 32 to a rear side 33 of the first element 29. The handling device 1 is thus in the first unloaded state. Starting from the first unloaded state, the helical spring 25 can be compressed by a displacement of the inlet lever 10 in the actuation direction 4. In contrast, when the radial projection 31 bears axially against the rear side 33, the actuating device 1 is in the first actuating state. Starting from the first actuating state, the helical spring 25 cannot be compressed or cannot be compressed any further when the entry lever 10 is displaced in the actuating direction 4. Thus, the compression of the helical spring 25 is prevented by the axial abutment of the radial projection 31 at the back side 33.

Furthermore, the actuating device 1 has a sleeve-shaped second element 34, which has an axial passage 35 through which the inlet rod 10 extends coaxially. The second element 34 and the first element 29 are arranged at least partially concentrically to one another, wherein the second element 34 has a larger cross section than the first element 29. The first element 29 is thus guided radially in the second element 34. The second element 34 has a cross-sectional narrowing 36 which engages behind a radial projection 37 of the first element 29. The cross-sectional constriction 36 is located in the region of the rear end of the second element 34, as viewed in the actuating direction 4. The radial projection 37 is located at the front end of the first element 29, as seen in the actuating direction. Furthermore, the second element 34 has a radial projection 38 located in front of the cross-sectional constriction 36 in the actuating direction 4, wherein the third spring device 24 or the first leg spring 27 is supported on the end face of the radial projection 38. The first spring device 22 and the third spring device 24 are therefore connected in series by the first element 29 and the second element 34. According to fig. 1, the radial projection 38 is located at the front end of the second element 34, as seen in the actuating direction 4. Furthermore, the entry lever 10 has a radial projection 48. The radial projection 48 is coupled to the entry lever 10 and axially abuts against the second element 34 in a first operating state, so that, starting from the first operating state, the second element 34 can be displaced together with the entry lever 10 when the entry lever 10 is displaced further in the operating direction 4.

According to the exemplary embodiment shown in fig. 1, the actuating device 1 has a first guide disk 39 and a second guide disk 40, the first guide disk 39 being arranged in front of the second guide disk 40, as seen in the actuating direction 4. The guide discs 39 and 40 are displaceable relative to each other in the axial direction. Furthermore, each of the guide disks 39 and 40 has an axial passage through which the inlet rod 10 extends. The first guide disk 39 has a rear side, against which the end side of the first leg spring 27 rests, and an end side, against which the rear side of the elastomer spring 26 of the second spring device 23 rests. The second guide disk 40 has a rear side, against which the end side of the elastomer spring 26 rests, and an end side, against which the rear side of the second leg spring 28 rests. Furthermore, the second guide disk 40 has an axial projection 41 which extends in the direction of the first guide disk 39. According to the illustration from fig. 1, the end face of the first guide disk 39 has an axial distance 42 from the axial projection 41. Thus, the handling device 1 is in the second unloaded state. Starting from the second unloaded state, the elastomer spring 26 can be compressed when the entry lever 10 is displaced in the actuating direction 4. In contrast, the actuating device 1 is in the second actuating state when the end face of the first guide disk 39 bears axially against the axial projection 41. Starting from the second loaded state, the elastomer spring 26 cannot be compressed or cannot be compressed any further by a displacement of the feed rod 10 in the actuating direction 4. The compression of the elastomer spring 26 is thus prevented by the axial abutment of the end face of the first guide disk 39 against the axial projection 41.

The pedal travel simulator 18 is designed in such a way that it is held preloaded between the inlet rod 10 on the one hand and a component arranged at least indirectly on the first housing part 13 on the other hand. That is to say, the pedal travel simulator 18 provides, at least in the case of the cross-sectional constriction 17 of the first housing part 13 axially abutting against the radial projection 16 of the second housing part 15, an axial force acting on the inlet rod 10 counter to the actuation direction on the one hand, and on the other hand an axial force acting in the actuation direction 4 on a component arranged at least indirectly at the first housing part 13.

In this case, the actuating device 1 has a fourth spring device 43 for prestressing the pedal travel simulator 18. The fourth spring device 43 is supported on one side on a pressure plate 49, which bears axially against the spindle 8, wherein the pressure plate 49 is displaceable with the spindle 8 at least in the actuating direction 4, and the spindle 8 is displaceable with the pressure plate 49 at least opposite to the actuating direction 4. The fourth spring device 43 is therefore designed as a return spring 43 for the spindle 8. The fourth spring device 43 is supported on the other side on a housing part, not shown, which is arranged at least indirectly on the first housing 13. Finally, the transmission of axial forces from the inlet rod 10 to a housing part, not shown, is effected by means of the inlet piston 30, the pedal travel simulator 18, the bearing 19, the spindle nut 7, the spindle 8 and the fourth spring device 49.

The manner of functioning of the operating device 1 in the normal operation of the operating device 1 is explained below. Normal operation is to be understood here as the following operation of the actuating device 1: in this operation, master brake cylinder 2 is actuated by brake force generator 5 when inlet rod 10 is displaced in actuating direction 4. In normal operation, the threaded spindle 8 is displaced in the actuating direction 4 as a function of the extent of the displacement of the feed rod 10 in the actuating direction 4. Furthermore, depending on the extent of the displacement of the entry lever 10 in the actuating direction 4, either the first spring device 22, the first spring device 22 and the second spring device 23 or the first spring device 22, the second spring device 23 and the third spring device 24 are compressed by the displacement of the entry lever 10. By compressing the

spring devices

22, 23 and 24, an axial force acting in the actuating direction 4 is transmitted to the spindle nut 7. The spindle nut 7 is basically supported in an axially displaceable manner. In normal operation, however, the electric motor of the braking force generator 5, as a result of its operation, causes a reaction force which prevents the spindle nut 7 from being displaced axially.

The manner of functioning of the actuating device 1 in emergency braking operation is explained below. In this case, the emergency braking operation is to be understood as the following operation of the actuating device 1: in operation, no actuation of the master brake cylinder 2 by the braking force generator 5 takes place during displacement of the inlet rod 10 in the actuation direction 4, for example because the electric motor has a malfunction. In this case, the axial displacement of the screw nut 7 is not prevented by the reaction force. The

spring devices

22, 23 and 24 are also compressed during emergency braking operation as a function of the extent of the displacement of the entry lever 10 in the actuating direction 4. As a result, an axial force acting in the actuating direction 4 is transmitted to the spindle nut 7, wherein the spindle nut 7 is displaced in the axial direction for actuating the master brake cylinder 2 when the axial force acting in the actuating direction 4 exceeds the force exerted by the return spring 43 and acting on the spindle nut 7 opposite the actuating direction 4. In particular, the second element 34 bears axially against the spindle 8 during a hard braking operation when the inlet rod 10 is displaced in the actuating direction 4, so that an axial force acting in the actuating direction 4 is then transmitted on the one hand via the pedal travel simulator 18 and the bearing 19 to the spindle nut 7 and on the other hand via the second element 34 to the spindle 8.

Fig. 2 shows a longitudinal section through a second exemplary embodiment of the actuating device 1. In contrast to the exemplary embodiment from fig. 1, the actuating device 1 shown in fig. 2 has a first spring device 22 with a helical spring 25 and an elastomer spring 47. Here, the helical spring 25 and the elastomer spring 47 are arranged one behind the other, so that the helical spring 25 and the elastomer spring 47 bear against one another in the axial direction. The first spring device 22 of the exemplary embodiment shown in fig. 2 is designed to provide a higher damping than the first spring device 22 of the exemplary embodiment shown in fig. 1 of the actuating device 1. Thus, a greater damping effect is produced by the first spring means 22 of the embodiment shown in fig. 2.

Claims

1. An actuating device for a brake system, comprising an entry lever (10) which can be displaced by a brake pedal in an actuating direction (4); with a displacement sensor (11) which has a measured value transmitter (14) and a receiver (12) and which is designed to detect a displacement position of the entry lever (10); and with a braking force generator (5) having a spindle drive (6) with a spindle nut (7) and a spindle (8), wherein the spindle nut (7) is mounted so as to be rotatable about a rotational axis (46) extending in a steering direction (4), and the spindle (8) can be displaced in the axial direction by rotation of the spindle nut (7), and the braking force generator is designed to: displacing the spindle (8) in an axial direction for actuating a master brake cylinder (2) of the brake system as a function of the detected displacement position, wherein the inlet rod (10) can be displaced in the axial direction relative to the spindle (8), and wherein the actuating device (1) has a pedal travel simulator (18) which can be actuated by means of the inlet rod (10), characterized by a bearing (19) which transmits an axial force and which is held in the axial direction between the spindle nut (7) on the one hand and the pedal travel simulator (18) on the other hand.

2. Operating device according to claim 1, characterized in that the bearing (19) is configured as a rolling bearing, in particular a ball bearing, or as a sliding bearing.

3. Handling device according to claim 2, wherein the bearing (19) configured as a rolling bearing has a first bearing ring (20) and a second bearing ring (21), wherein the bearing rings (20, 21) are rotatable relative to each other about a rotational axis (46), and wherein rolling bodies of the bearing (19) are arranged radially or axially between the bearing rings (20, 21).

4. Operating device according to one of the preceding claims, characterized in that the entry rod (10) extends coaxially through at least a section of the pedal stroke simulator (18).

5. Operating device according to one of the preceding claims, characterized in that the pedal travel simulator (18) has a first spring device (22), in particular a helical spring (25) and/or an elastomer spring (47).

6. Operating device according to one of the preceding claims, characterized in that the pedal travel simulator (18) has a second spring device (23), in particular having at least one elastomer spring (26).

7. Operating device according to one of the preceding claims, characterized in that the pedal travel simulator (18) has a third spring device (24), in particular having at least one belleville spring (27, 28).

8. Operating device according to one of claims 5 to 7, characterized by a sleeve-shaped first element (29) which is displaceable in the axial direction relative to the screw (8), wherein the first element (29) has an axial groove (44) in which the first spring device (22) is arranged, and wherein the handling device (1) has a first unloaded state and a first handling state, the radial projection (31) of the inlet rod (10) having an axial distance (32) from a rear side (33) of the first element (29) in the first unloaded state, in the first operating state, the radial projection (31) axially abuts against a rear side (33) of the first element (29) after compressing the first spring device (22), so that further compression of the first spring means (22) is prevented by the axial abutment.

9. Operating device according to any one of claims 5 to 8, characterized in that the screw (8) has an axial groove (45) in which either the first spring device (22) or the first spring device (22) and the first element (29) are arranged.

10. Handling device according to any of claims 8 and 9, c h a r a c t e r i z e d by a second element (34) which is displaceable in axial direction relative to the first element (29), through which the inlet rod (10) extends coaxially, wherein the second element (34) has a radial projection (38) at the end side of which the third spring means (24) rests, wherein the second element (34) has a larger cross section than the first element (29), and wherein the first element (29) has a radial projection (37), a cross sectional narrowing (36) of the second element (34) engaging behind the radial projection (37).

11. Operating device according to one of claims 6 to 10, characterized by two guide discs (39, 40) which can be displaced relative to one another in the axial direction, wherein an end side of a first one of the guide discs (39) bears axially against a rear side of the second spring device (23) and a rear side of a second one of the guide discs (40) bears axially against an end side of the second spring device (23), wherein at least one of the guide discs (40) has an axial projection (41) which extends in the direction of the other guide disc (39), and wherein the operating device (1) has a second unloaded state in which the axial projection (41) of the one guide disc (40) has an axial spacing (42) from the other guide disc (39), in the second operating state, the axial projection (41) axially abuts against the further guide disk (39) after the second spring device (23) has been compressed, so that further compression of the second spring device (23) is prevented by the axial abutment.

12. Operating device according to one of claims 7 to 11, characterized in that the third spring device (24) has a first and a second belleville spring (27, 28), wherein these belleville springs (27, 28) are arranged spaced apart with respect to one another in the axial direction, and wherein either the second spring device (23) or the second spring device (23) and the guide discs (39, 40) are arranged between the belleville springs (27, 28).

13. Handling device according to any of claims 7-12, c h a r a c t e r i z e d in that the bearing (19) is axially retained between the screw nut (7) on the one hand and a belleville spring (28) of the third spring means (24) on the other hand.

14. Operating device according to one of the preceding claims, characterised in that the pedal travel simulator (18) is pretensioned between the entry lever (10) on the one hand and a component arranged on the first housing part (13) on the other hand.

15. Actuating device according to claim 14, characterized by a fourth spring device (43) which, for preloading the pedal travel simulator (18), is supported on one side on a component arranged on the first housing part (13) and on the other side on the pedal travel simulator (18).