Pedal force simulation device with stroke-dependent hysteresis, actuation system and clutch

Abstract

Pedal force simulation device (1) for a motor vehicle, comprising a housing (2), a piston (4) accommodated in the housing (2) so as to be displaceable along a longitudinal axis (3), and a spring device (5) acting on the piston (4), wherein the spring device (5) has at least one resilient pre-tensioning section (6a, 6b), and said at least one pre-tensioning section (6a, 6b) is pressed against a conical surface (7a, 7b) of a wedge segment (8) fixed to the piston, rising and / or falling along the longitudinal axis (3), in such a way that the piston (4) is axially supported by means of the spring device (5) by a supporting force which changes over its displacement path, wherein a friction device (9) is provided, and the friction device (9) is operatively connected to the piston (4) in such a way that a friction force acting axially on the piston (4) changes over the displacement path, wherein the friction device (5) has a spring device (5) connected,second friction component (12), wherein the second friction component (12) has a friction surface (13a, 13b) provided on the at least one pre-tensioning section (6a, 6b), characterized in that the at least one pre-tensioning section (6a, 6b) forms the friction surface (13a, 13b) on a side facing away from the wedge segment (8).

Description

[0001] The invention relates to a pedal force simulation device for a motor vehicle, in particular for a clutch pedal of a motor vehicle, such as a car, truck, bus, or other commercial vehicle, comprising a housing, a piston accommodated in the housing so as to be displaceable along a longitudinal axis, and a spring device acting on the piston. The spring device has at least one resilient preloading section, and this at least one preloading section is pressed against a conical surface of a wedge segment fixed to the piston, which rises and / or falls along the longitudinal axis, in such a way that the piston is axially supported by the spring device through a supporting force that changes over its displacement path (and inhibits the displacement of the piston). The invention also relates to an actuation system for a motor vehicle clutch comprising this pedal force simulation device, as well as to a clutch comprising this actuation system.

[0002] Generic pedal force simulation devices, also referred to as pedal force simulators, are well known in the art. In this context, DE 10 2015 204 702 A1, for example, discloses a device for simulating force on an actuating element of a vehicle, in particular a pedal force simulator, with a piston connected to the actuating element via a piston rod. When actuated, the actuating element moves the piston axially within a cylinder against the spring force of a spring.

[0003] However, the disadvantage of the pedal force simulation devices known from the prior art has been that they are often unsuitable for applications requiring piston stroke-dependent hysteresis. DE 10 2014 225 996 A1 discloses a pedal force simulation device according to the preamble of claim 1. Further prior art is described in DE 10 2017 103 994 A1.

[0004] It is therefore the object of the present invention to eliminate the disadvantages known from the prior art and in particular to provide a pedal force simulation device which can be adapted to the stroke-dependent hysteresis.

[0005] This is achieved according to the invention in that a friction device is provided and the friction device is operatively connected to the piston in such a way that a friction force acting axially on the piston (through the friction device) changes over the displacement path.

[0006] Thus, with relatively little effort, the corresponding pedal force simulation device is designed with a stroke-dependent hysteresis. The pedal force simulation device thus has a stroke-dependent hysteresis adapted to the respective application.

[0007] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0008] With regard to the friction device, it is therefore also advantageous if it has a first friction component that is rigidly connected to the piston. This allows one component of the friction device to be accommodated in the existing piston in a space-saving manner, thus saving additional installation space.

[0009] In this context, it is expedient for the first friction component to have a friction element fixedly attached to the piston. The friction element is preferably designed to be elastically compressible. This further simplifies the design of the friction device.

[0010] Furthermore, the friction device comprises a second friction component that is firmly connected to the spring device, preferably firmly connected to the at least one preloading section. The second friction component is preferably in direct frictional contact with the first friction component. This also simplifies the design of the friction device.

[0011] In order to further simplify the structure of the friction device, the second friction component has a friction surface provided / formed on the at least one preloading section (immediately / directly).

[0012] The friction surface is advantageously designed to rise and / or fall in the axial direction (i.e., along the longitudinal axis in the retraction or extension direction of the piston relative to the housing). This allows for particularly customized hysteresis adjustment.

[0013] The friction surface further preferably has a first longitudinal region which has a first inclination / inclination relative to the longitudinal axis or runs parallel to the longitudinal axis, and a second longitudinal region which is axially adjacent to the first longitudinal region and has a second inclination / inclination relative to the longitudinal axis, wherein the second inclination is greater than the first inclination.

[0014] According to the invention, the friction surface of the at least one pre-tensioning section is formed on a side of the at least one pre-tensioning section facing away from the wedge segment.

[0015] Furthermore, it is practical if the spring device has two preload sections that are pressed against two opposing conical surfaces of the wedge segment. A friction surface is preferably provided / formed for each preload unit, with a separate friction element being applied to each friction surface, or the same friction element being applied to both friction surfaces. This achieves a particularly effective distribution of the forces acting on the piston.

[0016] Furthermore, the invention relates to an actuation system for a motor vehicle clutch, with the pedal force simulation device according to the invention according to at least one of the previously described embodiments.

[0017] The invention also relates to a clutch, such as a friction clutch, for a drive train of a motor vehicle with this actuation system.

[0018] In other words, a pedal force simulator (pedal force simulation device) with stroke-dependent hysteresis is thus realized. In order to adjust the friction or hysteresis in this pedal force simulator as a function of the stroke (depending on the displacement position of the piston), the invention proposes providing an additional friction element between the piston and a leaf spring (preloading section). The additional friction element and a corresponding counter contour (friction surface) of the leaf spring allow the hysteresis to be easily adapted to the specific customer requirements.

[0019] The invention will now be explained in more detail below with reference to a figure in conjunction with a preferred embodiment.

[0020] It shows the only Fig. 1 a longitudinal sectional view of a pedal force simulation device according to the invention, whereby the overall structure of this pedal force simulation device can be seen particularly well.

[0021] The figure is merely schematic in nature and serves solely to understand the invention.

[0022] In Fig. Figure 1 illustrates the pedal force simulation device 1 according to the invention according to a preferred embodiment. The pedal force simulation device 1 typically serves to simulate a pedal force exerted by a clutch pedal of a motor vehicle when actuating a clutch. During operation, the pedal force simulation device 1 is arranged in the signal transmission path between the clutch pedal and the clutch. The pedal force simulation device 1 thus serves to simulate a disengagement path or an engagement path of the clutch, such as a friction clutch, on the part of the clutch pedal. The pedal force simulation device 1 is typically a component of an actuation system of this clutch and is preferably operatively connected (electrically, electrohydraulically, etc.) to a slave cylinder arranged directly on the side of the clutch.

[0023] The pedal force simulation device 1 comprises a housing 2, also referred to as a cylinder. A cylindrical receiving space 16 is formed in the housing 2. A piston 4 is displaceably arranged in the receiving space 16. In particular, a base body 19 of the piston 4 is displaceably guided in the housing 2 / the receiving space 16. In particular, the base body 19 has running surface regions 20 that are displaceably guided along a longitudinal axis 3 of the housing 2 by contact with the housing 2. The piston 4 also has a piston rod 17 that is connected to the base body 19 of the piston 4. The clutch pedal is, in turn, displaceably coupled to the piston rod 17 in a typical manner during operation. A preload spring 18, here in the form of a helical compression spring, serves to support the piston 4 in its disengaged position according to Fig. 1. The preload spring 18 is clamped between the housing 2 and a piston-fixed / piston rod-fixed area.

[0024] A spring device 5 also acts on the piston 4 during its displacement. The spring device 5 has two resilient preloading sections 6a and 6b anchored in the housing 6 above a base region 21. The preloading sections 6a and 6b are arranged with their free ends in the housing 2 so as to be resilient relative to the base region 21, in particular so as to be deformable in the radial direction with respect to the longitudinal axis 3. The preloading sections 6a and 6b each interact with a conical surface 7a, 7b of a wedge segment 8, which is a component of the piston 4, namely the base body 19. The wedge segment 8 is firmly / non-displaceably connected to the base body 19.

[0025] The two conical surfaces 7a, 7b, each of which is in contact / operative connection with one of the preloading sections 6a, 6b, face away from each other with respect to the longitudinal axis 3. A first conical surface 7a interacts with a first preloading section 6a. For this purpose, a roller / roller element 22 is provided on a radial inner side of the first preloading section 6a, which is directly supported on the first conical surface 7a. The first preloading section 6a is pressed against the first conical surface 7a with a certain preload force in the radial direction (on the part of its roller element 22). A second conical surface 7b interacts with a second preloading section 6b. For this purpose, a roller / roller element 22 is provided on a radial inner side of the second preloading section 6b, which is directly supported on the second conical surface 7b.The second preloading section 6b is pressed against the second conical surface 7b with a certain preload force in the radial direction (on the part of its roller element 22). The two preloading sections 6a and 6b are thus spaced apart from one another in the radial direction with respect to the longitudinal axis 3 and are pressed against the conical surfaces 7a, 7b by opposing radial sides of the wedge segment 8. The preloading sections 6a, 6b are therefore essentially designed as leaf spring segments / leaf springs.

[0026] The conical surfaces 7a and 7b each form different longitudinal regions that adjoin one another along the longitudinal axis, with each conical surface 7a, 7b having an initially rising and subsequently falling region / longitudinal region. The two conical surfaces 7a, 7b are mirror-symmetrical to one another with respect to the longitudinal axis 3.

[0027] If the piston 4 is moved from its release position to Fig. 1 is pushed into the housing 2 / displaced in its retraction direction, the roller elements 22 roll along the conical surfaces 7a, 7b and thus, due to the elastic preload of the preload sections 6a, 6b, an axial supporting force that changes over the displacement path and acts axially on the piston 4. By appropriately designing the preload sections 6a, 6b, in particular with regard to the spring hardness, together with the preload spring 18, an ideal clutch characteristic curve is simulated over the displacement path of the piston 4.

[0028] According to the invention, in order to additionally adjust the existing hysteresis of the piston stroke (when moving it in the retraction direction and oppositely in the extension direction), a friction device 9 is provided in the pedal force simulation device 1. This friction device 9 is essentially operatively connected to the piston 4 in such a way that it generates a friction force acting on the piston 4 that changes axially over the displacement path of the piston 4. This friction device 5 thus specifically generates a friction force that changes its magnitude depending on the displacement path of the piston 4 in the housing 2.

[0029] As in Fig. As can also be clearly seen in Figure 1, this friction device 5 comprises two friction components 10, 12. A first friction component 10 is formed by two friction elements 11a, 11b. These two friction elements 11a, 11b can, as in this exemplary embodiment, be formed separately / individually from one another, or, according to further embodiments, can be formed integrally with one another. Each friction element 11a, 11b interacts with a friction surface 13a, 13b of a second friction component 12.

[0030] A first friction surface 13a is formed directly on the first preload section 6a. The first friction surface 13a is formed on a side of the first preload section 6a that is (radially) remote from the first conical surface 7a / the wedge segment 8. A second friction surface 13b is formed directly on the second preload section 6b. The second friction surface 13b is formed on a side of the second preload section 6b that is (radially) remote from the second conical surface 7b / the wedge segment 8. The first friction element 11a is in direct frictional contact with the first friction surface 13a; the second friction element 11b is in direct frictional contact with the second friction surface 13b. When the piston 4 is displaced, due to the piston-fixed arrangement of the friction elements 11a, 11b, a targeted / defined rubbing of the friction elements 11a, 11b occurs along the corresponding preload section 6a, 6b forming a housing-fixed component.

[0031] In order to generate friction dependent on the displacement path of the piston 4, each friction surface 13a, 13b has a plurality of longitudinal regions 14, 15 that differ in terms of their inclination relative to the longitudinal axis 3. In this exemplary embodiment, a first longitudinal region 14 of each friction surface 13a, 13b runs parallel to the longitudinal axis 3. A second longitudinal region 15, which is axially immediately adjacent to this first longitudinal region 14, is formed transversely / obliquely to the first longitudinal region 14 and therefore has a greater inclination than the first longitudinal region 14 relative to the longitudinal axis 3. Both friction surfaces 13a and 13b are, as a whole, mirror-symmetrical to one another with respect to the longitudinal axis 3.

[0032] Thus, when the piston 4 is moved (in its retraction direction) along its displacement path from the Fig.1 into an engagement position to slide the friction elements 11a, 11b along the respective first longitudinal region 14 and subsequently along the respective second longitudinal region 15, so that the friction force acting on the piston 4 on the part of the friction device 9 changes.

[0033] In other words, the pedal force simulation device 1 according to the invention is provided with an additional friction element 11a, 11b between the piston 4 and the leaf spring 6a, 6b and an associated contour 13a, 13b on the leaf spring 6a, 6b. The friction and thus the hysteresis can be varied and adjusted depending on the stroke. The friction element 11a, 11b is also connected to the piston 4. Upon actuation, the leaf spring 6a, 6b is deflected, thereby varying the contact force on the friction element 11a, 11b over the stroke. The contour 13a, 13b on the leaf spring 6a, 6b allows the friction to be adapted and configured to customer requirements. List of reference symbols 1 pedal force simulation device 2 housings 3 Longitudinal axis 4 pistons 5 Spring device 6a first preamble section 6b second preamble section 7a first conical surface 7b second conical surface 8 wedge segment 9 Friction device 10 first friction component 11a first friction element 11b second friction element 12 second friction component 13a first friction surface 13b second friction surface 14 first longitudinal section 15 second longitudinal area 16 Recording room 17 Piston rod 18 Preload spring 19 basic bodies 20 Tread area 21 Basic area 22 roller element

Claims

[1] Pedal force simulation device (1) for a motor vehicle, comprising a housing (2), a piston (4) accommodated in the housing (2) so as to be displaceable along a longitudinal axis (3), and a spring device (5) acting on the piston (4), wherein the spring device (5) has at least one resilient prestressing section (6a, 6b) and this at least one prestressing section (6a, 6b) is pressed against a conical surface (7a, 7b) of a wedge segment (8) fixed to the piston, which conical surface rises and / or falls along the longitudinal axis (3), in such a way that the piston (4) is axially supported by means of the spring device (5) by a supporting force which changes over its displacement path, wherein a friction device (9) is provided and the friction device (9) is operatively connected to the piston (4) in such a way that a friction force acting axially on the piston (4) changes over the displacement path, wherein the friction device (5) has a, firmly connected to the spring device (5),second friction component (12), wherein the second friction component (12) has a friction surface (13a, 13b) provided on the at least one preloading section (6a, 6b), characterized by that the at least one prestressing section (6a, 6b) forms the friction surface (13a, 13b) on a side facing away from the wedge segment (8). [2] Pedal force simulation device (1) according to claim 1, characterized by that the friction device (5) has a first friction component (10) connected to the piston (4) in a manner which prevents it from being displaced. [3] Pedal force simulation device (1) according to claim 2, characterized by that the first friction component (10) has a friction element (11a) fixedly attached to the piston (4). [4] Pedal force simulation device (1) according to one of the preceding claims, characterized by that the friction surface (13a, 13b) rises and / or falls in the axial direction. [5] Pedal force simulation device (1) according to one of claims 1 to 4, characterized by that the spring device (5) has two pre-tensioning sections (6a, 6b) which are pressed against two conical surfaces (7a, 7b) of the wedge segment (8) facing away from one another. [6] Actuating system for a motor vehicle clutch, comprising a pedal force simulation device (1) according to one of claims 1 to 5. [7] Coupling with an actuation system according to claim 6.

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