Pedal feel simulator

Abstract

The invention relates to a pedal feel simulator (10) for a vehicle braking system, comprising a piston (18) guided axially displaceably against a spring force in a cylinder bore (14). The piston (18) is designed as a deformed piston (18) and has a cylindrical or conical recess (34) on an axial side (30) facing the pressure.

Description

[0001] The present invention relates to a pedal feel simulator for a vehicle braking system. Furthermore, the invention relates to a vehicle braking system comprising such a pedal feel simulator. State of the art

[0002] Newer vehicle developments enable driving with an increasing degree of automation, which also places new demands on associated systems, such as the braking system. In particular, pressure generation using an external power source must be possible, even independently of the vehicle driver. At the same time, the driver must be given the impression that they are actively controlling the associated system when operating the vehicle's pedals. For this purpose, pedal simulators are regularly used in vehicles. These simulate a system to be operated on an associated pedal. The pedal thus gives the driver largely the same feeling as if a comparable system were operated automatically, i.e., not simulated.

[0003] DE 10 2022 207 233 A1 describes a pedal feel simulator for a vehicle braking system, comprising a piston guided axially displaceably in a cylinder bore against a spring force. The piston is formed in two parts, consisting of a first and a second piston part. The first piston part is adapted such that it is structurally identical across multiple pedal feel simulator types. The second piston part is designed to be structurally identical across multiple pedal feel simulator types with different axial dimensions.

[0004] The object underlying the invention is to provide a pedal feel simulator for a vehicle braking system which has a lower weight and can be produced more economically.

[0005] The object is achieved by a pedal feel simulator for a vehicle braking system having the subject matter of patent claim 1. Preferred embodiments can be found in the dependent claims. Disclosure of the invention

[0006] The invention provides a pedal feel simulator for a vehicle braking system, comprising a piston guided axially displaceably in a cylinder bore against a spring force. The piston is designed as a formed piston and has a cylindrical or conical recess on an axial side facing the pressure.

[0007] The axial side facing the pressure is the side of the piston on which the brake pressure applied by the pedal is applied. Forming is a process step in which the workpiece is plastically shaped into the desired form. This means that no material is removed from the workpiece. The material required to form such a workpiece is correspondingly reduced. The formed piston can therefore be manufactured more economically. By forming a recess in the piston, the material required can be reduced even further. In addition, a piston formed in this way is lighter. Since the recess is formed in the forming step, no additional work step is necessary to create this recess. The time required to manufacture the piston can therefore also be kept low.

[0008] In a preferred embodiment of the invention, the piston has a plurality of axial extensions on an axial side facing away from the pressure, which delimit a cylindrical receiving space for a spring, wherein the axial extensions are arranged in a crenellated manner around the cylindrical receiving space. The axial side of the piston facing away from the pressure is the side opposite the springs of the pedal feel simulator. The axial projections protrude from this side in the axial direction. A crenellated arrangement of the extensions is understood to mean an arrangement in which a gap is provided between each two extensions. The gap formed between the extensions reduces the amount of material required to form the piston. Furthermore, the weight of the piston is further reduced. The axial extensions and the gaps are formed during the forming step.This eliminates the need for an additional manufacturing step to create the gaps between the axial projections. This makes it possible to produce a pedal feel simulator economically and with a lower weight.

[0009] In a further preferred embodiment of the invention, recesses are formed on the axial side facing the pressure, via which the recess is fluidly connected to an outer circumference of the piston. Advantageously, the recesses are formed in the radial direction of the piston. The recesses make it possible to vent the air accumulated in the recess when filling the brake system. This prevents the air present in the recess from adversely altering the desired pedal feel.

[0010] Preferably, the piston is designed as a cold-formed part. Cold forming the workpiece has the advantage of not only strengthening the workpiece but also achieving better material utilization. In contrast to machining, processing time can be reduced.

[0011] In an advantageous further development, an outer circumference of the piston is machined. Machining the outer circumference is advantageously performed after forming the piston. Machining can improve the dimensional accuracy of the piston. Furthermore, such a machining step improves the surface quality of the outer circumference.

[0012] Advantageously, the recess has an axial depth of at least 1 / 3 of the axial length of the piston. Particularly advantageously, the recess has an axial depth of at least half the axial length of the piston. Such a recess makes it possible to significantly reduce the weight of the piston and the required material. Accordingly, a pedal feel simulator can be manufactured that is both cost-effective and lightweight.

[0013] In a further advantageous embodiment, a machined groove is arranged on the outer circumference. A seal is arranged in the groove to seal the axial side of the piston facing the pressure. The seal rests against the cylinder bore. Machining the groove allows for quick and easy formation.

[0014] According to a practical embodiment, the axial length of the extensions can be machined to achieve a desired pedal feel. In other words, only one type of piston is manufactured. To create different desired pedal feel profiles, only the axial length of the extensions needs to be adjusted by machining. The piston is thus versatile. Furthermore, only one forming tool is required for different pedal feel profiles, making such a pedal feel simulator economically feasible.

[0015] According to a further advantageous embodiment, the axial side facing the pressure is designed such that the piston can be clamped via the recess to allow machining. This already creates a clamping area for machining. Such a design of the axial side allows the piston to be easily machined for reworking the outer circumference.

[0016] The object underlying the invention is additionally achieved by a vehicle braking system that includes such a pedal feel simulator. Such a vehicle braking system achieves the properties and advantages described above.

[0017] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description. It shows: Fig. 1 sectional view of a pedal feel simulator according to an embodiment of the invention, Fig. 2 Top view of the axial side of the piston facing the pressure, and Fig. 3 Sectional view of the piston according to an embodiment of the invention.

[0018] In Fig. Figure 1 shows a sectional view of a pedal feel simulator 10 according to an embodiment of the invention. The pedal feel simulator 10 comprises a cylinder bore 14 in which a piston 18 is axially movable. The piston 18 is designed as a cold-formed piston 18. A hat-shaped cover 22 is arranged on the cylinder bore 14, in which a disc spring assembly 26 is positioned to simulate a brake feel.

[0019] On an axial side 30 of the piston 18 facing the brake pressure, a conical recess 34 is formed on the piston 18. In this exemplary embodiment, the conical recess 34 extends from the axial side 30 to the center of the piston 18. This recess 34 is formed via a forming step. The recess 34 reduces the weight of the piston 18. A groove 42 is provided on an outer circumference 38 of the piston 18, in which a seal 46 is arranged, via which the axial side 30 facing the brake pressure is sealed off from the disc spring assembly 26.

[0020] On an axial side 50 of the piston 18 facing away from the brake pressure, a plurality of axial extensions 54 are formed, forming a cylindrical receiving space 58 for a spring 62. In the illustrated embodiment, the spring 62 is a helical spring. The axial extensions 54 are also formed by a forming step. The axial extensions 54 have gaps 66 between them, forming a crenellated structure. The gaps 66 between the axial extensions 54 allow the weight of the piston 18 to be reduced. The helical spring 62 is arranged between the piston 18 and the disc spring assembly 26 and forms a jump-in function for the pedal feel simulator 10.

[0021] Fig. Figure 2 shows a plan view of the axial side 30 of the piston 18 facing the pressure. This figure shows the conical recess 34. The axial side 30 additionally has recesses 70 extending radially, via which the conical recess 34 is fluidically connected to the outer circumference 38 of the piston 18. These recesses 70 allow venting of the conical recess 34. A stop surface 74 for clamping in a machining machine is formed annularly around the conical recess 34 on the axial side 30. The piston 18 can thus be clamped in the machining machine via this stop surface 74, so that the outer circumference 38 of the piston 18 can be machined.

[0022] Fig.Figure 3 shows a sectional view of the piston 18 according to an embodiment of the invention. This figure shows which areas of the piston 18 can still be machined after a forming step. For example, the groove 42 on the outer circumference 38 is machined. The axial length of the extensions 54 can also be adjusted to achieve a desired pedal feel. 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 2022 207 233 A1

[0003]

Claims

[1] Pedal feel simulator (10) for a vehicle brake system, with a piston (18) guided axially displaceably against a spring force in a cylinder bore (14), characterized by that the piston (18) is designed as a deformed piston (18) and has a cylindrical or conical recess (34) on an axial side (30) facing the pressure. [2] Pedal feel simulator (10) according to claim 1, characterized by that the piston (18) has, on an axial side (50) facing away from the pressure, a plurality of axial extensions (54) which delimit a cylindrical receiving space (58) for a spring (62), wherein the axial extensions (54) are arranged in a crenellated manner around the cylindrical receiving space (58). [3] Pedal feel simulator (10) according to claim 1 or 2, characterized by that recesses (70) are formed on the axial side (30) facing the pressure, via which the depression (34) is fluidically connected to an outer circumference (38) of the piston (18). [4] Pedal feel simulator (10) according to one of the preceding claims, characterized by that the piston (18) is designed as a cold-formed part. [5] Pedal feel simulator (10) according to one of the preceding claims, characterized by that an outer circumference (38) of the piston (18) is machined. [6] Pedal feel simulator (10) according to one of the preceding claims, characterized by that the recess (34) has an axial depth of at least 1 / 3 of the axial length of the piston (18). [7] Pedal feel simulator (10) according to one of the preceding claims, characterized by that a machined groove (42) is arranged on the outer circumference (38). [8] Pedal feel simulator (10) according to one of the preceding claims, characterized by that an axial length of the extensions (54) can be adjusted by machining to form a required pedal feel. [9] Pedal feel simulator (10) according to one of the preceding claims, characterized bythat the axial side (30) facing the pressure is designed such that the piston (18) can be clamped via the recess (34) in order to be machined. [10] Vehicle braking system comprising a pedal feel simulator (10) according to any one of the preceding claims.

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