Electric anti-lock braking system for motor vehicles

Abstract

Title: Electric anti-lock braking system for motor vehicles. The control device comprises a body including a base (11) supporting a cylinder (12) receiving a piston (2) equipped with an actuating pad (23) for the driver's foot, and a spring system (3) including a return spring (31) for the piston (2) to its rest position, and, in parallel, an auxiliary spring (32) acting on the piston (2) from a piston (2) deflection threshold (S). A sensor (4) detects the translation of the piston (2), and an operating unit (5) connected to the translation sensor (4) generates a signal transmitted to the vehicle's control unit. Figure 2

Description

Title of the invention: Anti-lock braking system for motor vehicles. FIELD OF THE INVENTION

[0001] The invention relates to an electrical control device for a motor vehicle of the brake or accelerator control type. STATE OF THE ART

[0002] In the automotive field, manufacturers are increasingly developing electrical control devices for braking and acceleration functions to replace mechanical devices with articulated pedals and to significantly reduce the number of components and their size in order to create available space for other equipment.

[0003] According to the prior art, skates or pedals are known which use articulated pedal kinematics or other linear movement guided in a plane.

[0004] PURPOSE OF THE INVENTION

[0005] The present invention aims to develop a control device of the accelerator or brake control type allowing a reduction of components in linear guidance systems and facilitating their manufacture through modularity and adjustments to meet the multiple demands of customers.

[0006] DESCRIPTION AND ADVANTAGES OF THE INVENTION

[0007] The invention relates to an electrical control device of the accelerator or brake pedal type for a vehicle, operated by the driver,

[0008] comprising: a body with a base carrying a cylinder receiving a piston equipped with an actuating pad for the driver's foot, a spring system comprising a spring for returning the piston to its rest position, and an auxiliary spring, in parallel with the return spring and acting on the piston from a piston deflection threshold, a piston translation sensor, an operating unit connected to the translation sensor to generate a signal transmitted to the vehicle management unit, to control the braking system in response to the driver's push P on the pad.

[0009] According to an advantageous feature, the device comprises

[0010] a thrust sensor cooperating with the auxiliary spring to detect the thrust exerted on the piston and generate a signal transmitted to the management unit.

[0011] Particularly interestingly, the piston cylinder has an axial cavity opening into the underside of the piston and receiving the helical return spring, supported against the bottom of the cavity and against a spring support connected to the base through the bottom of the cylinder.

[0012] This support is preferably a plate surmounted by a cylindrical relief engaged in the end of the return spring to guide and hold it, the support being integral with an adjustment rod freely passing through the bottom of the cylinder.

[0013] The thrust sensor makes it possible to provide a useful signal to form the control signal that the processing unit provides to the vehicle's braking system.

[0014] In addition, since the return spring is supported on an adjustable support, this allows the spring characteristic to be adjusted and adapted more precisely.

[0015] According to another advantageous feature, the piston is crossed diametrically by a branch fixed in translation to the piston and whose ends protrude from the cylinder and rest on the auxiliary spring, external to the cylinder.

[0016] This embodiment allows the auxiliary spring to be controlled in a particularly advantageous way as a function of the stroke (or push) exerted on the pad of the control device by the driver.

[0017] This branch helps to guide and maintain the piston in a precise orientation relative to its axis, which is important for various reasons and in particular for the orientation of the pad carried by the top of the cylinder.

[0018] This orientation is guaranteed by the guide slots of the cylinder whose orientation is parallel to the axis of the cylinder to receive the spindle.

[0019] Advantageously, for reasons of overall symmetry, the guide slots open into two diametrically opposed sectors, bordered by two pairs of parallel ribs, connecting the cylinder to the base plate.

[0020] This structure advantageously uses the space left free between the sectors delimited by the radial ribs, connecting the cylinder by the base to reinforce the structure of the body of the device without having to increase certain dimensional characteristics.

[0021] According to another characteristic, the auxiliary spring has a spring constant (or more precisely a spring characteristic) which is not linear unlike that of a helical spring such as the main return spring whose spring characteristic is effectively a spring constant.

[0022] Advantageously, the piston carries a magnet on the part of its body that engages with the cylinder, and the cylinder has a magneto-sensitive translation sensor along the path of the magnet as the piston is pushed in. This allows for particularly precise, efficient, and reliable detection of the piston stroke, providing a signal that confirms or reinforces the other signals received by the central control unit, which then provides the braking signal.

[0023] According to one feature, the body has externally to the cylinder a housing for the translation sensor in a position associated with the path of the magnet carried by the piston.

[0024] This housing is advantageously located in a sector between two radial ribs and on either side of the piston in a diametrical position, in the preferred case of a device comprising two magnets on the piston in a diametrical position, cooperating with two sensors in a corresponding position, in order to increase redundancy. This redundancy is thus obtained simply without modifying the overall size of the control device.

[0025] Indeed, the magnet is doubled on the piston in diametrically opposed positions, angularly offset around the axis of the piston relative to the axial plane of the spindle and the translation sensor is also doubled, associated with the respective path of the doubled element.

[0026] According to another advantageous feature, the auxiliary spring is housed in a cavity outside the cylinder in a sector delimited by two radial ribs. This sector is preferably the other sector to the pair of sectors than the one or two sectors occupied by the housing of the translation sensor(s).

[0027] The control device according to the invention allows:

[0028] - a compact and robust design,

[0029] - adjusting the pedal feel,

[0030] - a segmented, symmetrically designed system using pairs of components identical, which translates into savings.

[0031] The control device also facilitates the complete separation and sealing of electronic components and connectors for robust redundancy.

[0032] Among its many other advantages, the device allows:

[0033] - the adjustment of the main spring preload by the threshold force, i.e. the thrust associated with the adjustable threshold

[0034] - the adjustment of the transition point between the linear and non-linear parts of the curve of the stroke / push,

[0035] - the possibility of adjusting the non-linear part of the spring characteristic auxiliary using different interchangeable springs (made of elastomer or other materials) and with a modular set of components depending on the characteristics required.

[0036] The symmetrical design allows the use of pairs of identical components, which represents a significant saving.

[0037] The complete separation and isolation of the electronic components and connectors ensures robust redundancy and near-total separation of the compartments Electronic components, compared to mechanical components, avoid any risk of contamination. Brief description of the drawings

[0038] The present invention will be described in more detail below with reference to an embodiment of an electrical control device shown schematically in the accompanying drawings in which:

[0039] [Fig-1] Perspective view of the control device without its cover,

[0040] [Fig.2] Axial cross-sectional view of the control device passing through the spindle of the piston,

[0041] [Fig.2A] axial cross-sectional view according to [Fig.2] of the body of the control device,

[0042] [Fig.2B] Axial cross-sectional view of the device body through a plane perpendicular to the plane of section of [Fig.2A],

[0043] [Fig.2C] Detail view of [Fig.2A],

[0044] [Fig.2D] Example of spring thrust / stroke curve,

[0045] [Fig.3] Axial cross-sectional view of the control device by a cutting plane perpendicular to the cutting plane of [Fig.2],

[0046] [Fig.3A] Axial cross-sectional view of the piston through a plane passing through the spindle,

[0047] [Fig.3B] Detail view of the axial section of [Fig.3],

[0048] [Fig.4] Perspective view of the control device with its cover and without its support pad,

[0049] [Fig.4A] Front view of the control device of the [Fig.1],

[0050] [Fig.4B] side view of the control device of the [Fig.l].

[0051] DESCRIPTION OF A MODE OF EMBODIMENT OF THE INVENTION

[0052] According to Figures 1, 2, 3, and 4, the electrical control device 100 consists of a body 1 formed by a base 11 and a cylinder 12 receiving a piston 2 actuated by the driver's foot pushing (P) in the direction of indentation against a spring system 3 composed of a main return spring 31 combined with an auxiliary spring 32. The action of the auxiliary spring 32 adds to that of the return spring 31 from a penetration threshold (S) of the piston 2 to generate a haptic response to the push (P) of the piston 2 by the driver. The assembly thus formed has overall rotational symmetry with respect to the axis ZZ of the piston 2.

[0053] The control device 100 is covered by a cover 17.

[0054] The stroke of the piston 2 is detected by a translation sensor 4 connected to a sensor signal processing unit 5 Si generating a signal SF corresponding to the driver's action request for the control of the braking action.

[0055] In more detail, according to [Fig. 1], the circular plate-shaped base 111 attached to the cylinder 12 has legs 112 distributed, preferably, regularly around the periphery and drilled for fixing device 100 to its location in the vehicle.

[0056] The circular plate 111 has a groove 113 for fixing a seal which receives the edge of the hood 17 so as to cover the body 1 in a manner that is sealed against dust and moisture.

[0057] The base 11 supporting the cylinder 12 is further connected to it by radial ribs 13 forming buttresses. It has, for example, four radial ribs 13 diametrically opposed in pairs and leaving between them sectors in which elements associated with the piston 2 are integrated outside the cylinder 12.

[0058] The top of the cylinder 12 is extended by the top of the piston 2 with a collar 211 and a reduced diameter ring 212 to receive, by fitting, the sleeve 231 of the pad 23 whose top 232 forms the support surface of the driver's foot.

[0059] According to figures 2, 2A which are sections by the same radial plane. The wall of the cylinder 12 is cut by two diametrically opposed guide slots 122 oriented parallel to the axis ZZ of the cylinder; these slots 122 serve to guide a pin 22 passing diametrically through the piston 2.

[0060] The pin 22 serves both to detect the thrust P exerted on the pad 23 and the piston 2, as will be seen later, and to lock the orientation around the axis ZZ to maintain the piston 2 and its pad 23 in a defined orientation.

[0061] the cylinder 12 has a bottom 121 provided with a sleeve 1211 receiving a spring support 16 for the main spring 31. The cylinder 12 is provided, in the upper part and near its bottom 121, with a bearing 123 for guiding the piston 2.

[0062] External to the cylinder 12, in the axial plane of the guide slots 122, the base 11 carries two cavities 14 receiving two auxiliary springs 32, each held in a cup 33 carried by an adjusting rod 34 with an interposed thrust sensor 35; the spring 32 has a non-linear characteristic. According to one embodiment ([Fig. 2C]), the auxiliary spring 32 is formed of a casing 32a and a conical inner pin 32b projecting into the casing; the spring 32 is a single piece of elastic material deformable by compression in the axial direction, parallel to the axis ZZ; its spring characteristic is variable and different depending on whether only its casing 32a is compressed or whether the casing 32a and the inner pin 32b are compressed by the piston 2.

[0063] The two parts of the auxiliary spring 32 are subjected to the thrust (P) on the piston 2 and transmitted by the pin 22 when the latter exceeds the penetration threshold (S) of the piston 2.

[0064] Fig. 2B is a section through an axial plane perpendicular to that of Fig. 2A; it shows the two housings 15 bordering the cylinder 12 in the two other segments delimited by the pairs of radial ribs 13 not appearing in this section.

[0065] The housings 15 each have a magnetic sensor 4 connected to a printed circuit board 41 and a pin 42.

[0066] Fig. 3 is a cross-sectional view of the device 100 along a cutting plane perpendicular to that of Fig. 2, and Fig. 3A is the cross-section of the piston alone along the cutting plane of Fig. 2. The piston 2 has a body 21, the lower part of which has a cavity 24 for receiving the main return spring 31, which is in the form of a helical spring; the return spring 31 bears at one end against the bottom 241 of the cavity 24 and at its other end against the spring support 16. The cavity 24 is provided with vents 242.

[0067] The body 21 of the piston is traversed by a diametrical bore receiving the pin 22 whose two ends outside the body 21 are provided with pads 221 to bear against the auxiliary springs 32.

[0068] Beneath the pin 22, the body 21 has a peripheral groove 243 with a rectangular cross-section to receive two magnets 25 in an angular position perpendicular to that of the pin 22. This position is shown in [Fig. 3], which shows two magnets 25 cooperating with the translation sensors 4 installed in the wall of the cylinder 12 under the corresponding guide slot 122. For reasons of redundancy and safety, the body 21 is equipped with a pair of magnets 25 associated with a pair of translation sensors 4. The sensors 4 are connected to a common circuit 41 (or separate circuits) as in the example for redundancy; the circuits are connected to a pin 42 for the transmission of the signals Si to the processing unit 5.

[0069] The thrust sensors 45 associated with the auxiliary springs 32 are also connected to the circuits 41 for signal processing and sending it to the processing unit 5.

[0070] The piston body 21 is held in the cylinder 12 by the bearings 123.

[0071] The top of the cylinder 21 carries the pad 23, the sleeve 231 of which is engaged on the segment 212 of piston 2.

[0072] According to the separate representation of [Fig.2C] the auxiliary spring 32 is embedded in the cup 33; the adjustable rod 34 is, for example, a threaded rod screwed into the circular plate 111, next to a radial rib 13; it is also offset relative to a pair of lugs 112. The screwing allows the height of the spring 32 relative to the pin 22 to be adjusted to set the threshold S.

[0073] For reasons of symmetry of the action of the piston 2 in the example above, the auxiliary spring 32 is doubled on either side of the cylinder 12 in the axial plane of the spindle 22 or of its guide slots 122. Functionally this pair of auxiliary springs 32 can be considered as a single auxiliary spring 32 since the structure of these two auxiliary springs 32 is the same.

[0074] Fig. 2D is an example of stroke / thrust curves of the control device 100.

[0075] According to the combination rule for springs 31, 32, their constants are added as soon as the pin 22 presses on them; upstream of this position, only the constant of the main spring 31 is involved; the combination of these springs only occurs after this contact:

[0076] - if the auxiliary spring 32 has a fixed spring constant, the result is a curve piston stroke / effort 2 composed of two right-hand segments:

[0077] - a first segment between the rest position O and the corresponding position A at the first contact of the pin 22 and the auxiliary spring 32 and a second straight segment from this point A, with a spring constant, sum of those of the springs 31, 32, until the end of the stroke at point B.

[0078] - if, as in this example, the constant of the auxiliary spring 32 is not fixed However, since the travel / force curve varies according to the degree of compression of the outer casing 32a and the inner pin 32b, it no longer varies linearly with the force (P) after contact between the pin 22 and the outer casing 32a. After contact with the inner pin 32b, which offers high elastic resistance to compression compared to a spring with a fixed constant, the variation is different. This allows for a meaningful haptic response of the degree of compression to the rider, whose foot rests on the pad 23 and will perceive the different compression zones.

[0079] Fig. 2D represents two diagrams of the combined spring 31, 32 relating the thrust P to the stroke of the piston 2 and highlighting the shape of the curve at OAB for a thrust P less than the thrust PS corresponding to the stroke at the point of contact of the spindle 22 with the top of the auxiliary spring 32. In this first part of the stroke, the curve is linear, the spring 31 having a fixed constant.

[0080] From the PS thrust, up to the maximum PM thrust, the combined spring 31 + 32 intervenes.

[0081] The two spring constants add up, which corresponds to the curve AB which, for simplicity, is a curve composed of two linear segments.

[0082] In reality, the constant of the auxiliary spring 32 is not fixed, but varies according to the degree of deformation of the spring 32; in the particular case of the shape of the spring 32 composed of two parts 32a, 32b, the overall constant is first that of the casing 32a by the pin 22 (stroke Se) and then also the contact of the pin 22 with the pin 32b, which again modifies the overall constant of the spring and the shape of the curve AB, the slope of which becomes steeper. Thus, in practice, the curve AB is a non-linear curve AB1 composed of two segments ABo and B1; B0 represents the point of the stroke Se from which the pin 32b comes into play according to this example.

[0083] According to an unrepresented variant, the auxiliary spring 32 is housed in the cavity 24 of the cylinder 2 on the spring support 16, but at a distance S from the bottom 241 of the cavity 24. The support 34 of the auxiliary spring 32 then passes through the spring support 16 so as to be able to adjust the distance S in the cavity, relative to the piston 2, independently of the adjustment of the spring support 16 with regard to the return spring 31.

[0084] In this variant, the pin 22 and the guide slots 121 can be retained to block the pivoting of the piston 2 around its axis ZZ, but the pin 22 will be shorter and will no longer extend beyond the guide slots 122. Other means of blocking the rotation of the piston are also conceivable.

[0085] Fig. 4 shows the control device 100 with its cover 17 also covering the legs 112 but without the pad 23. The separate pad 23 can be customized according to the manufacturer's request, while the other parts of the device 100 are manufactured identically.

[0086] Fig. 4A is a front view of the device 100, i.e., whose axial plane passes through the spindle 22. This view shows a pocket 15 between two radial ribs 10, 13 and behind these the two sectors occupied by the spindle 22 and the axial springs 32.

[0087] Fig. 4B shows a side view rotated 90° relative to that of Fig. 4A, revealing the cup 33 housed in the cavity 14 and the auxiliary spring 32 in the sector between two ribs 13.

[0088] NOMENCLATURE OF MAIN ELEMENTS

[0089] 100 Electrical control device

[0090] 1 Body

[0091] 11 Base

[0092] 111 Circular plate

[0093] 112 Paw

[0094] 113 Gorge

[0095] 12 Cylinder

[0096] 121 Background

[0097] 1211 Sleeve

[0098] 122 Guide slot

[0099] 123 Bearing

[0100] 13 Radial rib

[0101] 14 Cavity

[0102] 15 Housing

[0103] 16 Spring support

[0104] 161 Plate

[0105] 162 Relief

[0106] 163 Stem

[0107] 17 Hood

[0108] 2 Piston

[0109] 21 Cylindrical body

[0110] 211 Collar [YES] 212 Reduced diameter segment

[0112] 22 Pin

[0113] 221 Support pad

[0114] 23 Skate

[0115] 231 Sleeve

[0116] 232 Above

[0117] 24 Cavity

[0118] 241 Fund

[0119] 242 Event

[0120] 243 Gorge

[0121] 25 Magnet

[0122] 3 Spring system

[0123] 31 Main return spring

[0124] 32 Auxiliary spring

[0125] 32a Envelope

[0126] 32b Conical inner pin

[0127] 33 Cup

[0128] 34 Adjustment rod

[0129] 341 Stem

[0130] 35 Thrust sensor

[0131] 4 Translation sensor

[0132] 41 Printed circuit board

[0133] 42 Pin

[0134] 5 Processing Unit

[0135] ZZ Piston pin

[0136] YY Spindle axis

[0137] S Threshold

[0138] P Push on the combined spring

[0139] If Sensor Signal

[0140] SC Control signal

Claims

Demands

1. An electrical control device (100) of the type accelerator or brake pedal of a vehicle, operated by the driver, comprising: A. a body with a base (11) carrying a cylinder (12) receiving a piston (2) provided with an actuating pad (23) for the driver's foot, B. a spring system (3) comprising: - a return spring (31) of the piston (2) to its rest position, and - an auxiliary spring (32), in parallel with the return spring (31) and acting on the piston (2) from a piston (2) deflection threshold (S), C. a sensor (4) of the translation of the piston (2) and D. an operating unit (5) connected to the translation sensor (4) to generate a signal (SC) transmitted to the vehicle control unit (5) to control the braking system in response to the driver's push (P) on the pad (23).

2. Control device (100) according to claim 1, characterized in that it comprises a thrust sensor (35) cooperating with the auxiliary spring (32) to detect the thrust exerted on the piston (2), and generate a signal transmitted to the control unit (5).

3. Control device (100) according to claim 1, characterized in that the cylinder (21) of the piston (2) has an axial cavity (24) opening into the underside of the piston and receiving the helical return spring (31), pressed against the bottom (241) of the cavity (24) and against a spring support (16) connected to the base through the bottom (121) of the cylinder (12).

4. Electrical control device (100) according to claim 3, characterized in that the spring support (16) is a plate (161) surmounted by a cylindrical relief (162) engaged in the end of the return spring (31) to guide and hold it, the support (161) being integral with an adjusting rod (163) freely passing through the bottom (121) of the cylinder (12).

5. Control device (100) according to claims 1 and 2, characterized in that the piston (2) is crossed diametrically by a pin (22) fixed in translation to the piston and whose ends protruding from the cylinder (12) bear on the auxiliary spring (32) external to the cylinder (12).

6. Control device (100) according to claim 5, characterized in that the auxiliary spring (32) is split diametrically with respect to the cylinder (12) and the two ends of the spindle (22) each bear on a respective auxiliary spring (32) for a piston (2) depressed above the threshold (S).

7. Control device (100) according to claim 6, characterized in that the cylinder (12) is traversed by two guide slots (122) oriented parallel to the axis (ZZ) of the cylinder to receive the spindle (22).

8. Control device (100) according to claim 7, characterized in that the guide slots (122) open into two diametrically opposed sectors, bordered by two pairs of parallel ribs (13) connecting the cylinder to the plate (111) of the base.

9. Control device (100) according to claim 2, characterized in that the auxiliary spring (32) has a non-linear spring constant.

10. Control device (100) according to claim 1, characterized in that - the piston (2) carries a magnet (25) on the part of its body (21) engaged in the cylinder (12) and, - the cylinder (12) has a magnetosensitive translation sensor (4) on the path of the magnet (25) when the piston (2) is pushed in.

11. Control device (100) according to claims 1 and 10, characterized in that the body (1) has externally to the cylinder (12) a housing (15) for the translation sensor (4) in a position associated with the path of the magnet (25) carried by the piston (2).

12. Control device (100) according to claim 10, characterized in that the magnet (25) is doubled on the piston (2) in diametrically opposite positions, angularly offset around the axis ZZ of the piston relative to the axial plane of the spindle (22) and the translation sensor (4) is doubled, associated with a respective path of the doubled magnet (25).

13. Control device (100) according to claim 1, characterized in that the cylinder (12) is integral with the base (11) by being connected to it by radial ribs (13) delimiting sectors between them.

14. Control device (100) according to claims 1, 6 and 13, characterized in that the spring (32) is housed in a cavity (14) external to the cylinder (12) in the sector delimited by two radial ribs (13).

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