Wheel rotation speed measuring system equipped with a rotation speed sensor

Abstract

Title of the invention: System for measuring the rotational speed of a wheel equipped with a rotational speed sensor The invention relates to a system for measuring the rotational speed of a wheel comprising at least one rotational speed sensor (10) which extends along a main axis (100) and at least one transmission member (2) comprising at least one transmission joint and at least one tulip (22), the transmission joint being arranged in the tulip (22) and comprising at least three journals (213) whose axes are concurrent and contained in the same plane, the tulip (22) comprises an internal surface (221) and an external surface (222) which has a succession of projections (223) and hollows (224), characterized in that the rotational speed sensor (10) is arranged such that its main axis (100) passes through the succession of projections (223) and hollows (224) of the tulip (22). Abstract figure: Figure 2

Description

Title of the invention: System for measuring the rotation speed of a wheel equipped with a rotation speed sensor

[0001] The present invention relates to the field of measuring systems, in particular for motor vehicles, provided with a rotation speed sensor, and more particularly capable of measuring the rotation speed of a wheel.

[0002] Human means of transport have evolved considerably over the last few decades, the appearance of increasingly efficient vehicles as well as the increasing complexity of road traffic have led manufacturers to provide increasingly efficient driving assistance systems. These systems use, among other things, the rotation speed of a wheel as essential technical data for the operation of their system. Among these systems, ABS (acronym for "Antiblockiersystem" in German) or ESP (acronym for "Electronic stability program" in English) are remarkable. Information relating to the rotation speed of a wheel is also used, for example, to prevent an electric column lock from engaging while the vehicle is moving.

[0003] However, some vehicles, in particular motor quadricycles, do not have such driving assistance systems and consequently, no system for measuring the rotational speed of a wheel is provided.

[0004] It is known to equip vehicles initially without a wheel rotation speed measuring system with an inductive rotation speed sensor. Such sensors operate in combination with a pulse wheel attached to the wheel hub or to the transmission shaft. The inductive rotation speed sensor is placed opposite the pulse wheel, which has a toothed wheel shape. The rotation speed sensor can then detect the frequency of appearance of the teeth of the pulse wheel in its detection field. A wheel rotation speed measuring system comprising a pulse wheel has a degree of accuracy appropriate for a system such as ABS or ESP. On the other hand, the degree of accuracy of such a wheel rotation speed measuring system is excessive to detect a change in the rotation speed of a wheel of the order of a few rotations per minute.This excess precision of such a system for measuring the rotation speed of a wheel implies high costs which are not compatible with a motor quadricycle, for example.

[0005] It is also known to install an electromagnetic rotation speed sensor in combination with a magnetic encoder to determine the rotation speed of a wheel. However, this solution is difficult to implement, especially when the bearing is small and cannot accommodate a magnetic encoder seal.

[0006] The present invention falls within this context by proposing an alternative to existing solutions, this alternative offering a suitable measurement, less expensive and not requiring significant modifications to the vehicle to measure the rotation speed of a wheel.

[0007] The main object of the present invention is thus a system for measuring the rotational speed of a wheel comprising at least one rotational speed sensor which extends along a main axis and at least one transmission member comprising at least one transmission joint and at least one tulip, the transmission joint being arranged in the tulip and comprising at least three journals whose axes are concurrent and contained in the same plane, the tulip comprises an internal surface and an external surface which has a succession of projections and hollows, characterized in that the rotational speed sensor is arranged in such a way that its main axis passes through the succession of projections and hollows of the tulip.

[0008] The rotation speed sensor has an elongated shape along a main axis defined by the bisector of the detection angle of the sensor. This sensor is held in a fixing support, by means of fixing elements such as a screw, opposite a tulip of a transmission member that the vehicle comprises. This fixing support has an orifice intended to receive the rotation speed sensor. This rotation speed sensor is positioned such that the main axis of the rotation speed sensor intersects the external surface of the tulip. This tulip has a succession of projections and hollows formed on its external surface. This succession of projections and hollows results from the ramps present on the internal surface of the tulip allowing a transmission joint, engaged in this tulip, to transmit a rotary mechanical movement.This rotary mechanical movement causes the tulip to rotate in front of the rotational speed sensor, and thus transmits a rotational force to the vehicle wheel. The detection, by the rotational speed sensor, of the succession of projections and hollows allows this sensor to receive information relating to the rotational speed of the transmission member, and by extension of the wheel, independently of the position of the transmission joint. Indeed, the transmission joint has a variable position in the transmission member, unlike the external surface of this tulip. According to an advantageous characteristic, the rotational speed sensor is a magnetic rotational speed sensor. A magnetic rotational speed sensor generally comprises a magnet, a coil and a pole piece.The rotational speed sensor is placed opposite the outer surface of the tulip, the magnet producing a magnetic field which is concentrated by a pole piece. The magnetic field undergoes changes when passing the outer surface of the tulip. Indeed, the succession of projections and hollows present on the . The external surface of the tulip modifies the magnetic field by compressing it at the protrusions and expanding it at the hollows. The coil detects these changes in the magnetic field and produces an electrical signal which is detected by a computer to which the rotation speed sensor is connected.

[0009] According to an advantageous characteristic, the rotation speed sensor is a Hall effect sensor. Hall effect sensors are magnetic sensors comprising an internal electronic system which amplifies and / or processes the signal before transmitting it. Such sensors are more efficient and limit environmental disturbances. It should be noted that the rotation speed sensor of the system for measuring the rotation speed of a wheel can be of any type as long as it makes it possible to detect the passage of a part of the external surface of the tulip in the field of action of the sensor. It will be noted in particular that the rotation speed sensor of a wheel can be a magnetic sensor with flexible blades or a magnetoresistive sensor.

[0010] According to an advantageous characteristic, the system for measuring the rotational speed of a wheel comprises at least one steering knuckle of a vehicle. This steering knuckle comprises a support for fixing the rotational speed sensor, the support for fixing the rotational speed sensor being configured to arrange the rotational speed sensor in line with the succession of projections and hollows.

[0011] According to an advantageous characteristic, the support for fixing the rotation speed sensor is made from the same material as the stub axle.

[0012] According to an advantageous characteristic, the support for fixing the rotation speed sensor is a part added to the steering knuckle.

[0013] The rotation speed sensor mounting bracket may be an individually machined part, this part is then fixed to a steering knuckle by means of fixing elements such as one or more screws. This mounting bracket may also be made in one piece with the steering knuckle and in such a case, it is formed with the steering knuckle from a single, single piece.

[0014] Advantageously, the transmission joint forms a cardan joint - sliding relative to the tulip.

[0015] According to an advantageous characteristic, the tulip comprises a succession of projections and hollows of between three and six.

[0016] The projections and hollows present on the external surface of the tulip come from the modification of the internal surface of the tulip by ramps. These ramps allow the transmission joint to circulate inside the tulip. Depending on the number of journals present on the transmission joint, the internal surface of the tulip can accommodate between three and six ramps. Thus, the external surface of the tulip will have a succession of projections and hollows of between three and six.

[0017] According to a preferred characteristic, the transmission joint is a tripod joint, that is to say comprising three journals.

[0018] According to an advantageous characteristic, the rotation speed sensor is configured to discriminate between projections and hollows.

[0019] According to another advantageous characteristic, the fixing support is fixed to the steering knuckle by screws of a yoke of a brake caliper. The brake caliper is an element common to most vehicles, and in particular motor quadricycles, located near the tulip of the transmission member of the vehicle. The possibility of fixing the fixing support to this brake caliper allows the system for measuring the rotational speed of a wheel according to the invention to be compatible with a very large number of vehicles.

[0020] The invention also covers a motor vehicle comprising at least one system for measuring the rotational speed of a wheel, characterized in that the speed measuring system provides the vehicle with information relating to the movement or non-movement of said vehicle.

[0021] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the appended drawings on the other hand, in which:

[0022] [Fig-1] illustrates, schematically, a vehicle equipped with a system for measuring the rotational speed of a wheel according to the invention;

[0023] [Fig.2] illustrates, schematically, a perspective view of an organ of transmission of a vehicle equipped with a system for measuring the rotational speed of a wheel;

[0024] [Fig.3] illustrates, schematically, a sectional view of a tulip of the organ of transmission of [Fig.2] equipped with the system for measuring the rotation speed of a wheel. ;

[0025] [Fig.4] illustrates, schematically, a view of an alternative embodiment of the invention.

[0026] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0027] In the figures, the elements common to several figures retain the same reference.

[0028] In the detailed description which follows, the term “longitudinal” corresponds to a main direction of elongation of the object concerned.

[0029] In the detailed description which follows, the term “axial direction” corresponds to a direction parallel to the longitudinal axis of the object concerned.

[0030] [Fig.l] schematically represents a view of a system for measuring the rotational speed of a wheel integrated into a vehicle 1. The vehicle 1, according to the invention, is a motorized vehicle comprising at least three wheels, for example, a vehicle for transporting goods or people, an agricultural vehicle, or a motor quadricycle. In the embodiment represented by [Fig.l], the vehicle 1 is a four-wheel drive quadricycle which comprises an engine 3. This engine 3 may be an internal combustion engine, a hybrid engine, an electric motor or any other element making it possible to initiate a mechanical movement of the vehicle 1.

[0031] This mechanical movement initiated by the engine 3 is, in this embodiment, a rotary movement which passes to a gearbox 6 before being distributed to front or rear transmission shafts 8, as well as a central transmission shaft 8'. The front or rear transmission shafts 8 extend in a plane substantially orthogonal to a longitudinal axis 800 of the vehicle 1. These front or rear transmission shafts 8 ensure the transmission of the rotary mechanical movement, initiated by the engine 3, to the wheels 4 or 5.

[0032] The central transmission shaft 8' extends substantially along the longitudinal axis 800 of the vehicle 1. The rotary movement transmitted by the gearbox 6 is transmitted to a transfer box 7, located at the rear of the vehicle, by means of the central transmission shaft 8'. The rotary movement is finally distributed to the rear wheels by the rear transmission shafts 8.

[0033] It should be noted that each front or rear transmission shaft 8 as well as the central transmission shaft 8' have at their ends a transmission member 2. This transmission member 2 ensures the transfer of a mechanical movement, in particular a rotary mechanical movement, between the front or rear transmission shafts 8 and central 8' and on the one hand the wheels 4 and 5, on the other hand the gearbox 6 and the transfer box 7.

[0034] It will be noted at this stage that the invention applies to any one of the front or rear transmission shafts 8 or to the central transmission shaft 8'.

[0035] Figures 2 and 3 schematically represent respectively a perspective view of the transmission member 2 equipped with a rotation speed sensor 10 and a section of a tulip 22 of the transmission member 2 equipped with the rotation speed sensor 10. This transmission member 2 comprises a transmission joint which, in the embodiment shown, is a tripod joint referenced 21. This tripod joint 21 is, in the embodiment shown, integral with the shaft of transmission 8 and comprises three journals 213, each of these journals 213 being distributed at 120° inside the tulip 22. Each of these journals extends along a longitudinal axis, the longitudinal axes of the journals 213 being concurrent and contained in the same plane. These journals 213 have, at their distal end, rollers 211 which are rotatably and slidably mounted on these journals 213.

[0036] The tripod joint 21 engages in the tulip 22 which has an internal surface 221 and an external surface 222. This tulip 22 is a hollow bowl-shaped part and forms the first end of the part connecting the transmission shaft 8 to a spindle. The internal surface 221 of the tulip 22 has three ramps 212 in which the rollers 211 slide. These ramps 212 extend in the axial direction of the tulip 22 and form the part of the internal surface 221 furthest from the longitudinal axis 200 of the tulip 22. Thus, the tripod joint 21 is in a cardan-sliding connection relative to the tulip 22. This cardan-sliding connection allows the tripod joint 21 to perform a translation in a direction parallel to the longitudinal axis 200 relative to the tulip 22, and to block a rotation of the tripod joint 21 around this longitudinal axis 200 relative to the tulip 22.

[0037] These ramps 212 form on the internal surface 221 of the tulip 22 housings allowing the rollers 211 to circulate. These ramps 212, which in the embodiment shown are arranged angularly at 120° to each other and extend in the axial direction of the tulip 22, parallel to the longitudinal axis 200 of the tulip 22, form the part of the internal surface 221 furthest from the longitudinal axis 200 of the tulip 22. The part of the external surface 222, at the level of the part of the internal surface 221 forming these ramps 212, is formed of projections 223 separated from each other by hollows 224, such that this external surface 222 has a succession of projections 223 and hollows 224. These projections 223 form the part of the external surface 222 of the tulip 22 furthest from the longitudinal axis 200, while the hollows 224 form the part of the surface external 222 closest to the longitudinal axis 200.It should be noted that in the embodiment shown in [Fig.2], the tulip 22 comprises a succession of three projections 223 and three recesses 224 forming a succession of projections 223 and recesses 224 of three. It should also be noted that, in an alternative embodiment, the number of projections and recesses of the tulip may be greater depending on the type of transmission joint that is used within the transmission member. For example, the tulip may comprise a succession of six projections and six recesses.

[0038] Thus, this transmission member 2 ensures the transmission of the rotary movement between, on the one hand, the front or rear transmission shafts 8 and central 8' and, on the other hand, the wheels 4 and 5, the gearbox 6 and / or the transfer box 7. Indeed, the rotary movement coming from the front or rear transmission shaft 8 is transmitted by the joint tripod 21 to tulip 22 which in turn drives the rocket, then the wheel of the vehicle.

[0039] Figures 2 and 3 also illustrate a steering knuckle 11, which is generally formed from a molded and / or machined part comprising in its central part the knuckle and in its peripheral part suspension or steering arms used to connect the knuckle to the front or rear axle of the vehicle.

[0040] According to the invention, the rotation speed sensor 10 is placed opposite the tulip 22 in such a way that a main axis 100 of the rotation speed sensor 10 intersects the external surface 222 of the tulip 22, that is to say that the main axis 100 of the rotation speed sensor 10 passes through the succession of projections 223 and hollows 224 of the tulip 22. Thus, the rotation speed sensor 10 is able to discriminate between the projections 223 and the hollows 224 of the tulip 22.

[0041] The main axis 100 of the rotation speed sensor 10, according to the invention, corresponds to the bisector cutting a detection angle a of the rotation speed sensor 10 into two equal angles. The rotation speed sensor has an elongated profile extending along its main axis 100. Furthermore, the detection angle a of the rotation speed sensor 10, according to the invention, opens towards the tulip 22.

[0042] A fixing support 102, comprising an orifice intended to receive the rotation speed sensor 10. This rotation speed sensor 10 is, in the embodiment shown, a magnetic sensor comprising a magnet, a coil and a pole piece. This rotation speed sensor 10 is capable of generating a magnetic field, and of detecting the modifications of this magnetic field induced by the passage of the hollows 224 and the projections 223 of the external surface 222 of the tulip 22. The rotation speed sensor 10 comprises a fixing sole 1021 which, when the rotation speed sensor 10 is inserted into an orifice of the fixing support 102 provided for this purpose, comes into abutment against the fixing support 102. This fixing sole 1021 is held integral with the fixing support 102 by a screw 1024.The fixing support 102 is fixed on the steering knuckle 11 by two screws 1022 and 1023. In the embodiment shown in Figures 2 and 3, these holes, such as the holes 1111, are initially present on the steering knuckle 11 and are used, in particular in the case of a motor quadricycle, to fix the mudguard of the wheel.

[0043] It should also be noted that in an alternative embodiment, the fixing support 102 can be configured to be fixed in a “sandwich” manner with the brake caliper 111 and more precisely with the yoke of this brake caliper 111 in which a part of a brake disc 9 circulates. The screws 1112 and 1113 for fixing the yoke of the brake caliper 111 then serve as a means for fixing the fixing support 102 to the steering knuckle 11. The fixing support 102 being configured such that the main axis 100 of the rotation speed sensor 10, which is inserted into the orifice of the fixing support 102 and held by the fixing sole 1021 and the screw 1024, is intersecting the tulip 22, in particular of the external surface 222 of this tulip 22, such that the rotation speed sensor 10 detects the succession of hollows 224 and projections 223 of the external surface 222 of the tulip 22.

[0044] The fixing support 102 is an individually machined part, this part is not initially secured to the stub axle 11. Fixing means are necessary to secure it to the stub axle 11 which, in the embodiment shown, are screws 1022 and 1023. Thus, the fixing support 102 is a part added relative to the stub axle 11.

[0045] The rotation speed sensor 10 is supplied with energy by a cable 101, this cable 101 also connects the rotation speed sensor 10 to the various systems and applications of the vehicle 1 so as to deliver the information detected by the rotation speed sensor 10. Thus, the system for measuring the rotation speed of a wheel is capable of transmitting to the various systems and applications of the vehicle 1 information relating to the movement or absence of movement of the vehicle 1.

[0046] [Fig. 4] shows an alternative embodiment, in which the rotation speed sensor mounting bracket 10 is a ring 110. The rotation speed sensor 10 is inserted into the ring 110, the mounting base 1021 abutting against the ring 110 in such a way that a mounting element, which in the embodiment shown is a screw 1024, can hold this mounting base 1021 secured to a steering knuckle 1001. In the embodiment shown in [Fig. 4], the steering knuckle 1001 comprises a steering arm 1002, a support 1003 intended to receive a suspension ball joint, a suspension arm 1004 and a first mounting lug 1005 and a second mounting lug, not shown, intended to receive a yoke of the brake caliper 111 held secured to the steering knuckle 1001 by screws similar to screws 1112 and 1113.

[0047] The rotation speed sensor 10 is positioned, in this embodiment, such that its main axis 100 intersects the tulip 22 and more particularly the succession of projections 223 and hollows 224 of the external surface 222 of the tulip 22. This succession of projections 223 and hollows 224 is included in at least a part of the detection angle a of the rotation speed sensor 10. Thus, this rotation speed sensor 10 is able to discriminate the projections 223 with respect to the hollows 224. Furthermore, the rotation speed sensor 10 is powered and communicates with the various systems of the vehicle 1 by a cable 101. This cable 101 also connects the rotation speed sensor 10 to the various systems and applications of the vehicle 1 so as to deliver the information detected by the rotation speed sensor 10.

[0048] In the embodiment shown in [Fig. 4], the ring 110 and the stub axle 1001 are formed from a single piece, thus forming a single-piece assembly. for example from a foundry. Thus, the ring 110 is made from the same material as the stub axle 1001.

[0049] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

[0050] The invention, as just described, achieves the aim it set itself, and makes it possible to propose a system for measuring the rotational speed of a wheel comprising at least one transmission member and a rotational speed sensor, positioned opposite a tulip of the transmission member of a vehicle and whose main axis passes through a succession of projections and hollows of the tulip, making it possible to equip vehicles without wheel rotational speed sensors with a system adapted to the needs of these vehicles, for a less expensive cost than the systems which usually equip these vehicles.

Claims

Claims

1. System for measuring the rotational speed of a wheel of a vehicle (1), comprising at least one rotational speed sensor (10) which extends along a main axis (100), at least one transmission member (2) of the vehicle (1) comprising at least one transmission joint and at least one tulip (22) and at least one steering knuckle (11, 1001) of the vehicle (1), said transmission joint being arranged in said tulip (22) and comprising at least three journals (213) whose axes are concurrent and contained in the same plane, said tulip (22) comprises an internal surface (221) and an external surface (222) which has a succession of projections (223) and hollows (224), characterized in that the rotational speed sensor (10) is arranged such that its main axis (100) passes through the ... hollow (224) of the tulip (22), the rocket carrier (11, 1001) comprises a fixing support (102,110) of the rotation speed sensor (10), said fixing support (102, 110) of the rotation speed sensor (10) being configured to arrange the rotation speed sensor (10) in line with the succession of projections (223) and hollows (224) of the tulip (22).,

2. A system for measuring the rotational speed of a wheel according to claim 1, characterized in that the rotational speed sensor (10) is a magnetic rotational speed sensor.

3. System for measuring the rotational speed of a wheel according to any one of the preceding claims, characterized in that the fixing support (110) of the rotational speed sensor (10) is made in one piece with the steering knuckle (1001).

4. System for measuring the rotational speed of a wheel according to any one of claims 1 and 2, characterized in that the fixing support (102) of the rotational speed sensor (10) is a part attached to the steering knuckle (11).

5. System for measuring the rotational speed of a wheel according to any one of the preceding claims, characterized in that said transmission joint forms a cardan-sliding connection relative to said tulip (22).

6. System for measuring the rotational speed of a wheel according to any one of claims 1 to 5, characterized in that the tulip (22) comprises a succession of projections (223) and hollows (224) included between three and six.

7. System for measuring the rotational speed of a wheel according to any one of the preceding claims, characterized in that said transmission joint is a tripod joint (21).

8. System for measuring the rotational speed of a wheel according to any one of the preceding claims, characterized in that the fixing support (102) is fixed to the steering knuckle (11) by screws (1112, 1113) of a yoke of a brake caliper (111).

9. Motor vehicle (1) comprising at least one system for measuring the rotational speed of a wheel according to any one of the preceding claims, characterized in that the speed measuring system provides the vehicle (1) with information relating to the movement or absence of movement of said vehicle (1).

Images