Brake booster device for a vehicle braking system and manufacturing method for a brake booster device for a vehicle braking system

Abstract

The invention relates to a brake booster device for a vehicle's braking system, comprising an input rod component (10) which can be arranged to a brake actuating element (12) in such a way that the input rod component (10) is adjustable by means of a driver braking force exerted on the brake actuating element (12), and a guide body (14) with a bore (16) formed therein, into which the input rod component (10) projects at least partially, wherein an initial spring (18) is arranged in a compressible manner between an inner wall (20) of the bore (16) in the guide body (14) and an enlarged intermediate section (22) of the input rod component (10), and the initial spring (18) is restrained by means of a spring restraint device (24) in such a way that expansion of the initial spring (18) from a partially compressed state of the initial spring (18) is prevented by means of the spring restraint device (24).The invention also relates to a braking system for a vehicle. Furthermore, the invention relates to a manufacturing method for a brake booster device for a vehicle's braking system.

Description

[0001] The invention relates to a brake booster device for a vehicle's braking system. The invention also relates to a braking system for a vehicle. Furthermore, the invention relates to a manufacturing method for a brake booster device for a vehicle's braking system. State of the art

[0002] German patent DE 103 27 553 A1 describes an electromechanical brake booster. The electromechanical brake booster has a piston rod as its input rod component, which is adjustable by means of a braking force applied by the driver to the brake pedal. The piston rod runs through a bore in a guide body designed as the booster body. The guide body is adjustable by means of a motor and a gearbox so that a boosting force can be transmitted to a driver formed on the piston rod. In this way, the user of the electromechanical brake booster is intended to experience reduced effort during braking. Disclosure of the invention

[0003] The invention provides a brake booster device for a braking system of a vehicle with the features of claim 1, a braking system for a vehicle with the features of claim 11 and a manufacturing method for a brake booster device for a braking system of a vehicle with the features of claim 12. Advantages of the invention

[0004] Equipping the brake booster with the initial spring ensures a favorable / standard brake feel (pedal feel) for the driver. The initial spring is further secured by the spring restraint device, which provides it with an advantageous preload even when the brake actuator is in its unactuated state. This eliminates the conventional need for a spring / return spring to counteract the initial spring's engagement with the master cylinder. Since this function of the spring / return spring is eliminated in the present invention, a weaker spring / return spring can be installed in the brake booster. In a particularly advantageous embodiment, the spring / return spring can even be omitted entirely.Therefore, in the brake booster device that can be realized by means of the present invention, lower braking forces (initial forces) are already sufficient to build up brake pressure in a master brake cylinder connected to the brake booster device.

[0005] For example, the spring restraint device can include at least one compressible clamping element. The spring restraint device can therefore be manufactured cost-effectively.

[0006] In an advantageous embodiment, the spring restraint device comprises a spring housing consisting of at least a first housing part and a second housing part, wherein the first housing part is at least partially slidable into the second housing part. Such a spring restraint device ensures reliable pre-tensioning of the initial spring, even when no driver braking force is exerted on it.

[0007] In an advantageous embodiment, the brake booster device comprises, in addition to the initial spring restrained by the spring clamping device, an auxiliary spring by means of which the extended intermediate section of the input rod component is supported against the inner wall of the bore in the guide body. Such an auxiliary spring reliably ensures that the input rod component is displaced relative to the guide body, so that an interruption / termination of the brake actuation (e.g., releasing a brake pedal) is reliably detectable. Termination of the brake actuation thus causes a movement of the input rod component relative to the guide body. The driver therefore immediately feels a response from the brake actuation (e.g., a recoil) after terminating / interrupting its actuation.

[0008] For example, the auxiliary spring can be arranged in series with the initial spring. This can be easily achieved by arranging the auxiliary spring in a recess formed in the extended intermediate section of the input rod component. Such an arrangement of the auxiliary spring ensures its function as described in the preceding paragraph.

[0009] Alternatively, the auxiliary spring can also be arranged parallel to the initial spring. Such an arrangement of the auxiliary spring also reliably ensures its function as described above.

[0010] In an advantageous embodiment, the brake booster device comprises a motor connected to the guide body via at least one transmission component, wherein the guide body is adjustable by means of a booster force applied by the motor. The advantageous brake booster device can thus be designed, in particular, as an electromechanical brake booster. It should be noted, however, that the brake booster device described here is not limited to an electromechanical brake booster design.

[0011] In a further advantageous embodiment, the brake booster device comprises an output rod component to which the driver's braking force and / or the booster force can be at least partially transmitted, and which can be arranged in relation to a master brake cylinder such that at least one piston of the master brake cylinder is adjustable by means of at least a portion of the driver's braking force and / or the booster force. Thus, the booster force can advantageously be transmitted together with the driver's braking force to the at least one adjustable piston of the master brake cylinder, thereby relieving the driver of force during actuation of the brake actuator to decelerate the vehicle.

[0012] In a further advantageous embodiment, the brake booster device comprises a first return spring arranged between an inner wall of a housing of the brake booster device and a displaceable inner wall component of the brake booster device, the latter having an opening through which the output rod component projects. The brake booster device further comprises a second return spring arranged between a widened section of the output rod component and the inner wall component. This arrangement also ensures low initial forces required to build up brake pressure in the connected brake booster.

[0013] The advantages described in the preceding paragraphs are also guaranteed with a suitably designed braking system for a vehicle.

[0014] Furthermore, the advantages described above can also be achieved by implementing a corresponding manufacturing process for a brake booster device for a vehicle's braking system. Further development of the manufacturing process according to the embodiments and refinements described above is also possible and leads to the advantages outlined. Brief description of the drawings

[0015] Further features and advantages of the present invention are explained below with reference to the figures. They show: Fig. 1 a schematic representation of a first embodiment of the brake booster device; Fig. 2 a schematic representation of a second embodiment of the brake booster device; Fig. 3 a schematic representation of a third embodiment of the brake booster device; and Fig. 4 a schematic representation of a fourth embodiment of the brake booster device. Embodiments of the invention

[0016] Fig. Figure 1 shows a schematic representation of a first embodiment of the brake booster device.

[0017] The in Fig. Figure 1, a schematically depicted brake booster device for a vehicle's braking system, has an input rod component 10 which can be arranged / is arranged with respect to a brake actuation element 12 such that the input rod component 10 is adjustable by means of a driver braking force exerted on the brake actuation element 12. The input rod component 10 can, for example, be an input rod. However, it should be noted that the input rod component 10 is not limited to a specific external shape, such as a rod-shaped design. As a brake actuation element 12, the input rod component 10 can, for example, interact with a brake pedal. However, other embodiments of a brake actuation element 12 can also be used together with the brake booster device.

[0018] The brake booster device also includes a guide body 14 with a bore 16 formed therein. The guide body 14 can, for example, be a booster body. The input rod component 10 projects at least partially into the bore 16 formed in the guide body 14. An initial spring 18 (cut-in spring) is compressibly arranged between an inner wall 20 of the bore 16 in the guide body 14 and an expanded intermediate section 22 of the input rod component 10. This can also be understood to mean that the expanded intermediate section 22 is supported by the initial spring 18 (cut-in spring) against the inner wall 20 of the bore 16. The expanded intermediate section 22 can advantageously be located in an expanding central section of the bore 16, so that slippage of the expanded intermediate section 22 by means of two narrower end sections of the bore is prevented.The inner wall 20 preferably lies against a subsection of the guide body 14 that points away from the brake actuating element 12. The inner wall 20 can in particular be aligned with the brake actuating element 12.

[0019] By means of a spring restraint device 24, the initial spring 18 is restrained in such a way that expansion of the initial spring 18 from a partially compressed state is prevented by the spring restraint device 24. This can also be described as the spring restraint device 24 defining a partially compressed state of the initial spring 18, which allows further compression of the initial spring 18, but from which the initial spring 18 cannot expand. The spring restraint device 24 thus creates a preload on the initial spring 18 in its restrained state.

[0020] It is expressly pointed out that the spring-loaded restraint device 24 comprises at least one additional component arranged between the inner wall 20 of the bore 16 and the extended intermediate section 22 of the entry rod component 10. The spring-loaded restraint device 24 therefore does not refer to a locking mechanism that positions the inner wall 20 and the extended intermediate section 22 at a maximum distance.

[0021] By restraining the initial spring 18 using the spring restraint device 24, a suitable preload can be achieved without pre-tensioning the initial spring 18 by means of a spring / return spring. Conventionally, the preload of the initial spring 18 is often achieved by means of a spring / return spring supported against a master brake cylinder 26. The in Fig. The dashed arrows 28 in Figure 1 show the conventional force flow of the (not shown) spring / return spring, which, according to the prior art, causes the preload of the initial spring 18. To ensure sufficient preload of the initial spring 18, conventional brake boosters use comparatively large spring constants for the respective spring / return spring. In particular, the preload of the respective spring / return spring should generally be at least equal to the preload of the initial spring 18 so that the initial spring 18 is preloaded accordingly (at the rear stop).

[0022] In contrast, the brake booster device described here does not require pre-tensioning the initial spring 18 by means of a spring / return spring opposing the braking movement of the input rod component 10. Therefore, the brake booster device described here requires at most one spring / return spring opposing the braking movement of the input rod component 10, with a comparatively low spring constant. This ensures that the braking movement of the input rod component 10 is not subjected to high spring forces from the respective spring / return spring. The minimum force required to brake into the master cylinder 26 is thus reduced by restraining the initial spring 18 using the spring restraint device 24. Consequently, the brake booster device described here enables braking into the master cylinder 26 after overcoming a lower resistance / force threshold.This is particularly advantageous if the driver wants to build up brake pressure in the master brake cylinder 26 quickly and with a comparatively small force.

[0023] In particular, in some embodiments of the brake booster device, it is possible to dispense with equipping the brake booster device with a spring / return spring that counteracts the braking movement of the input rod component 10. This is the case, for example, in the embodiment of the Fig. Case 1. The brake booster device of the Fig. 1 merely has an amplifier mechanism return spring 29, by means of which the guide body 14, which has been moved from its initial position in the manner described below, can be moved back into this position. As shown by the Fig. As can be seen in Figure 1, the amplifier mechanism return spring 29 only opposes a movement of the guide body 14 from its initial position, but not a movement of the input rod component 10 relative to the guide body 14. Thus, the input rod component 10 can be adjusted by a non-zero differential travel relative to the guide body 14 without exerting any force on the amplifier mechanism return spring 29. Preferably, only the guide body 14 is supported by the amplifier mechanism return spring 29 against a wall in the brake booster device located close to the master brake cylinder 26.

[0024] The advantageous adjustability of the input rod component 10 (relative to the guide body 14) without compression of a spring / return spring conventionally required to pre-tension the initial spring 18 allows braking into the master brake cylinder 26 by means of a comparatively small force to be applied to the input rod component 10. The embodiment of Fig. 1 makes it significantly easier for a driver to build up pressure in the master brake cylinder 26 compared to conventional brake boosters.

[0025] In the embodiment of the Fig. 1. The spring restraint device 24 comprises a spring housing made up of at least a first housing part 30 and a second housing part 32, wherein the first housing part 30 is at least partially slidable into the second housing part 32. The housing parts 30 and 32 can also be described as interlocking clamp parts. It should be noted that the housing parts 30 and 32 need not be designed to completely surround the initial spring 28. Instead, the housing parts 30 and 32 can also be designed as interlocking clamp parts. Furthermore, the spring restraint device 24 can also include at least one compressible clamp part. The advantageous function of the spring restraint device 24, which contributes to reducing the force required for braking in the master brake cylinder 26, is not limited to a specific embodiment of the spring restraint device 24.

[0026] The brake booster device of the Fig. In addition to the initial springs 18, which are restrained by the spring restraint device 24, component 1 has an auxiliary spring 34 by means of which the extended intermediate section 22 of the input rod component 10 is supported by the inner wall 20 of the bore 16 in the guide body 14. The auxiliary spring 34 essentially causes the input rod component 10 to be displaced relative to the guide body 14, so that an interruption / termination of an actuation of the brake actuation element 12, such as the release of a brake pedal, can be reliably detected. The preload of the auxiliary spring 34 can be much smaller than the preload of the initial spring 18. The preload of the auxiliary spring 34 can be achieved, as shown by arrows 37, in particular by means of the master brake cylinder 26. Therefore, a spring is not required to preload the auxiliary spring 34. The auxiliary spring 34 also has little to no effect on the spring constant of anyThe auxiliary spring 34 counteracts the braking movement of the input rod component 10. It therefore does not increase the minimum force required to brake into the master brake cylinder 26 by applying it to the input rod component 10. The embodiment of the... Fig. 1 thus has an optimized spring arrangement through the restraint of the initial spring 18 and the additional use of the auxiliary spring 34.

[0027] The master brake cylinder 26 can, for example, be a tandem master brake cylinder. However, the brake booster device is not limited to interaction with a master brake cylinder 26 designed as a tandem master brake cylinder.

[0028] In the embodiment of the Fig. In 1, the auxiliary spring 34 is arranged in series with the initial spring 18. This can be understood to mean that a first end of the auxiliary spring 34 contacts the initial spring 18, while a second end of the auxiliary spring 34 abuts a surface of the extended intermediate section 22 of the input rod component 10.

[0029] For example, in this case, the auxiliary spring 34 is arranged in a recess 36 formed in the extended intermediate section 22 of the input rod component 10. Equipping the brake booster device with the auxiliary spring 34 is therefore possible without enlarging and / or requiring more installation space for the brake booster device.

[0030] As an extension, the brake booster device includes a motor 40 connected to the guide body 14 via at least one transmission component 38a to 38c, wherein the guide body 14 can be adjusted from its (forceless) initial position by means of a booster force applied by the motor 40. The brake booster device can thus be designed as an electromechanical brake booster.

[0031] The return of the guide body 14, which has been moved from its initial position by means of the motor 40, can be achieved by means of an optional separate spring 42. However, the separate spring 42 has no effect on the minimum force / initial force to be applied to the master brake cylinder 26 for braking after a failure of the motor 40, since the driver can move the input rod component 10 relative to the guide body 14 without compressing the separate spring 42.

[0032] Due to the advantageous design of the brake booster, which allows for the low minimum / initial forces for braking into the master cylinder 26 already described above, the driver can still brake into the master cylinder 26 with a comparatively small driver braking force even in the event of a failure of the engine 40. If the engine 40 fails in the illustrated embodiment, the driver only needs to overcome the spring forces of (not shown) springs in the master cylinder 26 to brake into it. The auxiliary spring 34 and the restrained initial spring 18 are connected in series with the springs in the master cylinder 26 and do not increase the braking / initial force required after an engine 40 failure. This significantly facilitates braking into the master cylinder 26 after an engine 40 failure.Thus, the brake booster device designed as an electromechanical brake booster exhibits the following characteristics. Fig. 1. an advantageous backup mode.

[0033] Optionally, at least one sensor 46 and 48 can be installed in a housing 44 (outer housing) of the brake booster device.

[0034] For example, a (magnetic) rotary angle sensor 46 can be provided in the housing 44 to determine / verify the operation of the motor 40. Likewise, a (magnetic) displacement sensor 48, in particular a rod displacement sensor 48, can be installed in the housing 44 to determine / verify an adjustment travel of the input rod component 10, an adjustment travel of the guide body 14, and / or a differential travel between the input rod component 10 and the guide body 14. However, equipping the brake booster device with at least one sensor 46 and 48 is optional.

[0035] Furthermore, the brake booster device can include an output rod component 50 to which the driver braking force and / or the booster force can be at least partially transmitted. The output rod component 50, for example, an output rod, is preferably arranged / arranged relative to the master brake cylinder 26 such that at least one piston of the master brake cylinder 26 can be adjusted by means of at least a portion of the driver braking force and / or the booster force. The driver braking force and / or the booster force can be at least partially transmitted to the output rod component 50 via a reaction disk 52, which is preferably arranged in an opening in the guide body 14 on a side facing the master brake cylinder 26. A reaction disk 52 can thus be used for the advantageous brake booster device.

[0036] Fig. Figure 2 shows a schematic representation of a second embodiment of the brake booster device.

[0037] The in Fig. Figure 2, schematically depicted, comprises, as a supplement to the embodiment described above, a movable inner wall component 60 in which an opening is formed through which the output rod component 50 projects. A first return spring 62 of the brake booster is arranged between an inner wall of a housing 44 of the brake booster and the movable inner wall component 60. (In this case, the movable inner wall component 60 is preferably supported by the inner wall of the housing 44 located close to the master brake cylinder 26 via the first return spring 62.) Furthermore, the brake booster additionally includes a second return spring 64, which is arranged between a widened section / end section 66 of the output rod component 50 and the inner wall component 60.This can also be understood to mean that the widened section / end section 66 of the output rod component 50 is supported by the second return spring 64 on the movable inner wall component 60. The widened section / end section 66 of the output rod component 50 is preferably directed away from the master brake cylinder 26, while the second return spring 64 is arranged on a side of the movable inner wall component 60 facing away from the master brake cylinder 26.

[0038] The inner wall component 60 is designed to be displaceable, so that it can be adjusted along with the guide body 14. However, due to the opening formed in the inner wall component 60, a braking movement of the input rod component 10 and / or the output rod component 50 does not cause the inner wall component 60 to adjust. The first return spring 62 therefore only opposes the adjustment movement of the guide body 14. The spring constant of the first return spring 62 thus has no influence on the minimum force required to brake into the master brake cylinder after a motor 40 failure.

[0039] The second return spring 64 has a comparatively small spring constant. It is therefore optimized with regard to preload. Since, after a failure of the motor 40, only the second return spring 64 counteracts braking into the master brake cylinder 26, this also applies to the brake booster device. Fig. 2. A brake pressure build-up in the master brake cylinder 26 is possible in backup mode by means of a comparatively small braking force.

[0040] Fig. Figure 3 shows a schematic representation of a third embodiment of the brake booster device.

[0041] In contrast to the previously described embodiment, the brake booster device features the Fig. 3. The auxiliary spring 34 is mounted outside the input rod component 10. Nevertheless, the auxiliary spring 34 is still in series with the restrained initial spring 18. This can also be described as follows: a first end of the auxiliary spring 34 contacts the initial spring 18, while a second end of the auxiliary spring 34 abuts an outer surface of the extended intermediate section 22 of the input rod component 10.

[0042] Fig. Figure 4 shows a schematic representation of a fourth embodiment of the brake booster device.

[0043] At the in Fig. In the schematically depicted brake booster device, the auxiliary spring 34 is arranged parallel to the initial spring 18. This can be understood to mean that the auxiliary spring 34 contacts the inner wall 20 of the bore 16 in the guide body 14 at a first end, while a second end of the auxiliary spring 34 abuts an outer surface of the extended intermediate section 22 of the input rod component 10. In particular, the auxiliary spring 34 can be arranged in a volume spanned by the (restrained) initial spring 18. The design possibilities of the brake booster device are therefore not limited to an arrangement of the auxiliary spring 34 in series with the restrained initial spring 18.

[0044] It is noted that the second return spring 64 in the embodiments of the Fig.2 to 4 are merely optional. As soon as the spring forces of the master brake cylinder 26 are sufficient to preload the auxiliary spring 34, the second return spring 64 can be dispensed with entirely.

[0045] All the brake booster devices described above can be manufactured by carrying out the manufacturing process for a brake booster device for a vehicle's braking system. However, the feasibility of the manufacturing process is not limited to the brake booster devices described above.

[0046] In the manufacturing process, an input rod component 10, which is adjusted by means of a driver braking force exerted on a brake actuating element 12 during operation of the brake booster device, is arranged at least partially in a bore 16 of a guide body 14. An initial spring 18 is arranged in a compressible manner between an inner wall 20 of the bore 16 in the guide body 14 and an enlarged intermediate section 22 of the input rod component 10. The initial spring 18 is restrained between the inner wall 20 of the bore 16 and the enlarged intermediate section 22 of the input rod component 10 by means of a spring restraint device 24 such that the spring restraint device 24 prevents the initial spring 18 from expanding from a partially compressed state.Examples of the input rod component 10, the brake actuation element 12, the guide body 14, the initial spring 18, and the spring restraint device 24 have already been described above. Therefore, a graphical representation of the manufacturing process is omitted.

Claims

[1] Brake booster device for a braking system of a vehicle with: an input rod component (10) which can be arranged in such a way as to a brake actuation element (12) that the input rod component (10) is adjustable by means of a driver braking force exerted on the brake actuation element (12); and a guide body (14) with a bore (16) formed therein, into which the input rod component (10) at least partially projects; characterized by an initial spring (18) which is compressibly arranged between an inner wall (20) of the bore (16) in the guide body (14) and an extended intermediate section (22) of the input rod component (10); and a spring restraint device (24) by means of which the initial spring (18) is restrained in such a way that an expansion of the initial spring (18) from a partially compressed state of the initial spring (18) is prevented by means of the spring restraint device (24), wherein the brake booster device comprises an output rod component (50) to which the driver braking force and / or the booster force can be transmitted at least partially, and which can be arranged to a master brake cylinder (26) in such a way that at least one piston of the master brake cylinder (26) can be adjusted by means of at least a part of the driver braking force and / or the booster force, wherein the brake booster device comprises a first return spring (62) which is arranged between an inner wall of a housing (44) of the brake booster device and a displaceable inner wall component (60) of the brake booster device, having an opening formed therein through which the output rod component (50) projects, and wherein the brake booster device additionally comprises a second return spring (64) which is arranged between a widened section (66) of the output rod component (50) and the inner wall component (60). [2] Brake booster device according to claim 1, wherein the spring clamp device (24) comprises at least one compressible clamp part. [3] Brake booster device according to claim 1 or 2, wherein the spring restraint device (24) comprises a spring housing made of at least a first housing part (30) and a second housing part (32), and wherein the first housing part (30) is at least partially displaceable into the second housing part (32). [4] Brake booster device according to one of the preceding claims, wherein the brake booster device comprises, in addition to the initial spring (18) being restrained by means of the spring restraint device (24), an auxiliary spring (34) by means of which the extended intermediate section (22) of the input rod component (10) is supported by the inner wall (20) of the bore (16) in the guide body (14). [5] Brake booster device according to claim 4, wherein the auxiliary spring (34) is arranged in series with the initial spring (18). [6] Brake booster device according to claim 5, wherein the auxiliary spring (34) is arranged in a recess (36) formed in the extended intermediate section (22) of the input rod component (10). [7] Brake booster device according to claim 4, wherein the auxiliary spring (34) is arranged parallel to the initial spring (18). [8] Brake booster device according to one of the preceding claims, wherein the brake booster device comprises a motor (40) connected to the guide body (14) via at least one transmission component (38a to 38c), and wherein the guide body (14) is adjustable by means of a booster force applied by the motor (40). [9] Braking system for a vehicle comprising a brake booster device according to one of the preceding claims. [10] Manufacturing method for a brake booster device for a braking system of a vehicle comprising the steps: Arranging an input rod component (10), which is adjusted during operation of the brake booster device by means of a driver braking force exerted on a brake actuating element (12), at least partially in a bore (16) of a guide body (14); characterized by the steps Arranging an initial spring (18) compressibly between an inner wall (20) of the bore (16) in the guide body (14) and an enlarged intermediate section (22) of the input rod component (10), wherein the initial spring (18) is arranged by means of a spring restraint device (24) in such a way that an expansion of the initial spring (18) from a partially compressed state of the initial spring (18) is prevented by the spring restraint device (24), wherein the brake booster device comprises an output rod component (50) to which the driver braking force and / or the booster force can be transmitted at least partially, and which is arranged to a master brake cylinder (26) in such a way that at least one piston of the master brake cylinder (26) is adjustable by means of at least a part of the driver braking force and / or the booster force, wherein the brake booster device comprises a first return spring (62) which is arranged between an inner wall of a housing (44) of the brake booster device and a displaceable inner wall component (60) of the brake booster device, having an opening formed therein through which the output rod component (50) projects, and wherein the brake booster device additionally comprises a second return spring (64) which is arranged between a widened section (66) of the output rod component (50) and the inner wall component (60).

Images