Brake caliper with a sensor and brake with such a caliper

Abstract

The invention relates to a brake caliper (5) comprising an actuator zone (7), a radially external arch (9) and an axially opposed zone (13) to the actuator zone (7), together defining a housing (15) for receiving a radially external part of a brake disc, the arch (9) securing the actuator zone (7) with the axially opposed zone (13), the actuator zone (7) being provided with a first brake pad (17.1) comprising a friction lining and an actuator comprising a motor (21) comprising a rotor and a mechanism (25) for converting the rotational movement of the rotor into a translational movement applying the pad (17.1) to the disc, the axially opposed zone (13) comprising a second brake pad (17.2) equipped with a friction lining, the caliper (5) further comprising a sensor (29) of a characteristic braking value characterized in that the sensor (29) of a characteristic braking value is disposed in the axially opposite zone (13). (Fig. 1).

Description

Title of the invention: Brake caliper comprising a sensor and brake comprising such a caliper. Technical field of the invention

[0001] The invention relates to a brake caliper comprising a sensor and to a brake comprising such a caliper. Prior art

[0002] It is known to produce numerically controlled braking systems (BBW in Anglo-Saxon terminology) comprising means for generating a braking command of the hydraulic pressure type, means for measuring the generated pressure, and means for applying the command in a closed loop. Furthermore, electric braking systems have been described, in particular electric disc brakes for motor vehicles, that is to say, brakes equipped with an electric motor that, via a mechanical transmission device, applies brake pads against the friction tracks of a brake disc upon command.

[0003] Furthermore, EP 1 438 519 describes an electric disc brake equipped with a force sensor and a force transmission path bypassing the force sensor. Unfortunately, this device only allows force measurement over a limited force range, thus preventing the brake from being operated under high forces.

[0004] It is therefore an object of the present invention to provide a disc brake caliper comprising a sensor for a characteristic braking value and a brake comprising such a caliper, enabling the brake to be controlled according to a setpoint. It is also an object of the present invention to provide a brake that is easily integrated into a vehicle's braking system. These objects are achieved by a brake caliper, a brake, and a method according to the invention. Description of the invention

[0005] The invention aims to overcome all or part of the drawbacks of the prior art. In this regard, the invention relates to a brake caliper comprising an actuator zone, a radially external arch, and a zone axially opposite to the actuator zone, together defining a housing for receiving a radially external portion of a brake disc. The arch connects the actuator zone to the axially opposite zone. The actuator zone is provided with a first brake pad comprising a friction lining and an actuator comprising a motor including a rotor and a mechanism for converting the rotational movement of the rotor into a translational movement applying the first pad to the disc. The axially opposite zone comprises a second brake pad provided with a lining. friction, the caliper further comprising a sensor of a characteristic braking value characterized in that the sensor of a characteristic braking value is disposed in the axially opposite zone.

[0006] The invention also relates to such a stirrup characterized in that the sensor is a force sensor.

[0007] The invention also relates to such a caliper characterized in that the sensor is a strain gauge.

[0008] The invention also relates to such a stirrup characterized in that it comprises a cable connected to the sensor and cable supports arranged on the outside of the stirrup.

[0009] The invention also relates to such a caliper characterized in that the cable is connected to a data processing and / or brake control circuit.

[0010] The invention also relates to such a caliper characterized in that the area axially opposite to the actuator area comprises caliper fingers and in that the sensor is carried by a caliper finger.

[0011] The invention also relates to such a caliper characterized in that the area axially opposite to the actuator area comprises caliper fingers and a space between the caliper fingers, a crossbar is disposed in said space and in that the sensor is carried by said crossbar.

[0012] The invention also relates to such a caliper characterized in that it comprises elastic means for applying the sensor to the second brake pad.

[0013] The invention also relates to such a caliper characterized in that the elastic means apply the sensor to a support plate of the second brake pad.

[0014] The invention also relates to a vehicle brake characterized in that it comprises a caliper according to the invention.

[0015] The invention also relates to such a vehicle brake characterized in that it comprises a yoke and a floating caliper.

[0016] The invention also relates to a braking system characterized in that it comprises a caliper according to the invention and data processing means receiving a characteristic value of the braking from the sensor and ensuring a correction of the measured value and a comparison of the corrected value with a setpoint value.

[0017] The invention also relates to such a braking system characterized in that it includes means for controlling the brake as a function of the difference between the corrected value and the setpoint value.

[0018] The invention also relates to such a braking system characterized in that the measurement, correction and control are ensured in a closed loop.

[0019] The invention also relates to a method for braking a motor vehicle comprising a first step consisting of measuring a characteristic braking value, a second step of correcting the measured value, a step developing a setpoint value, a step of comparing the setpoint value with the measured and corrected value and a braking command based on the result of comparing the measured corrected value and the setpoint value.

[0020] The invention also relates to such a method characterized in that the characteristic value of the braking is a braking force. Brief description of the figures

[0021] The present invention will be better understood upon reading the description of non-limiting examples of embodiments, with reference to the accompanying figures, which illustrate: • [Fig.1]: an axial cross-sectional view of a brake according to the invention; • [Fig. 2]: A perspective view of the axially external end of a first example of the realization of the brake of the [Fig.l]; • [Fig.3]: a perspective view of the axially external end of a second example of the implementation of the brake of [Fig.1]; • [Fig.4]: an explanatory diagram of the preferred example of the process according to the invention. Detailed description of at least one embodiment

[0022] For clarity, identical elements are identified by identical reference signs from one figure to another.

[0023] Figure 1 shows a preferred embodiment of a brake 1 according to the present design, comprising a yoke 3 and a floating caliper 5. The yoke 3 is provided with means for mounting it on a motor vehicle chassis. The caliper 5 is mounted to slide relative to the yoke 3. The caliper 5 has an actuator area 7 extended axially, along an axis parallel to the axis of rotation of a brake disc (not shown), by an arch 9 radially external to the disc and by a caliper nose 11 forming an axially opposite area 13 to the actuator area 7. The actuator area 7, the arch 9, and the caliper nose 11 form a housing 15 for receiving the radially external periphery of the brake disc. In other words, the caliper 5 straddles the brake disc.

[0024] The actuator area 7 includes an actuator that, upon command, applies a first brake pad 17.1 to a first face of the brake disc, and slides the caliper 5 relative to each 3 until a second brake pad 17.2, carried by the caliper nose 11, is applied to a second face of the disc, opposite said first face. The application of the first and second brake pads 17.1 and 17.2 to the disc, with a desired, time-modulated force, ensures, upon command, the braking and / or steering of the vehicle.

[0025] The actuator comprises a geared motor 19 formed by an electric motor 21 equipped with a rotor whose output shaft forms an input shaft of a speed reducer rotation 23 coupled to a mechanism 25 for transforming rotational motion into translational motion and a mechanical interface 27 with the first brake pad 17.1. The mechanism 25 advantageously includes a ball screw. The mechanism 25 for transforming rotational motion into translational motion is advantageously housed in a bore, typically a cylinder, of the actuator area 7 of the caliper 5.

[0026] According to the invention, the desired braking modulation is achieved based on a characteristic value of the braking force measured by a sensor 29. Preferably, this characteristic value is a function, advantageously increasing, of the braking force, i.e., the force applied by the pads 17.1 and 17.2 to the disc, thus generating a braking torque. In the preferred embodiment of the invention, the characteristic value is proportional to the braking force. Advantageously, the proportionality coefficient is greater than 1, for example, between 2 and 10,000, preferably between 50 and 1,000, for example, equal to 70, 150, or 300. In other words, the sensor 29 is subjected to a force less than the force exerted on the pads 17.1 and / or 17.2. This allows for a wider choice of sensors 29, including sensors with higher accuracy and / or lower cost.Advantageously, the proportionality between the force applied by the pads 17.1 and / or 17.2 on the brake disc and the force experienced and therefore measured by the sensor 29 extends over the entire braking force range, or at least over a predominant part of said range. Advantageously, the elastic means hold the sensor 29 against the second pad 17.2 without displacing the latter relative to the caliper nose 11, or displacing it only by a value less than a predetermined threshold, for example, to prevent the second pad 17.2 from contacting the disc, in order to avoid the occurrence of any residual braking torque, i.e., unwanted braking.

[0027] Alternatively, the sensor is a temperature, magnetic field, or other type of sensor. For example, a magnetic field sensor can measure the angular position of the disc and its variation, forming a wheel speed sensor (WWS) with increased angular resolution. In such a case, the disc has uniformly spaced ridges or slots on its periphery, at the level of housing 15. A temperature sensor can measure the temperature to modify the braking modulation.

[0028] The caliper 5 includes means 31 for communicating the measured values ​​to a processing circuit 33 of a vehicle braking system, advantageously to the brake control circuit. The communication means 31 include, for example, a cable and cable supports 35 for retaining this cable on the stirrup. Alternatively, the communication means 31 include a transmitting antenna and wireless transmission means.

[0029] It seems natural to place the sensor 29 at the level of the actuator zone 7 which generates the value to be measured, as illustrated in EP 1 438 519. In addition, the actuator zone 7 is located on the side of the information and / or data processing circuit 33 capable of receiving the values ​​measured by the sensor 29.

[0030] According to the invention, differently, the brake characteristic value sensor 29 is disposed in the axially opposite area 13 to the actuator area 7 of the caliper 5, typically in the caliper nose 11. Indeed, the second brake pad 17.2 carried by the caliper nose 11 also exerts a braking force which can therefore be measured. Moreover, the caliper nose 11 is an area with free spaces suitable for receiving the sensor 29. In addition, the communication means 31, for example the cable, are advantageously disposed in available spaces such as the outside of the caliper 5. In the illustrated example, means 35 for securing the data cable are disposed on the caliper nose 11, the arch 9, and in the actuator area 7 to connect the sensor 29 to the brake processing and control circuit 33.The cable is protected from the environment (electromagnetic interference, temperature and mechanical shocks), and is optionally inserted into a recess in the outer surface of the bracket.

[0031] In a first embodiment, the sensor 29 is analog, for example a strain gauge, for example of the piezoelectric type or by resistance variation, typically mounted to operate in compression. The cable transmits an electrical voltage, a current, or a frequency, which is a function of the measured value, to an analog-to-digital converter advantageously located in the processing and / or control circuit 33 of the brake 1. In a second embodiment, the sensor 29 is digital, and the cable directly transmits the measured digital value to the processing circuit 33.

[0032] Alternatively, brake 1 according to the invention and equipped with wireless communication means between the sensor 29 and the information processing circuit of the braking system.

[0033] In the preferred embodiment, illustrated in Figures 2 and 3, the caliper nose 11 comprises two caliper fingers 37 separated by a recess 39 allowing the receiving bore of the mechanism 25 for converting rotational motion into translational motion to be machined. Advantageously, the caliper nose 11 comprises a decorative plate 41, axially external, concealing the caliper fingers 37 and / or the recess 39. It is understood that calipers 5 with a tangentially continuous caliper nose 11, and therefore lacking a recess 39, do not fall outside the scope of the present invention.

[0034] Figure 2 shows an example of an embodiment of the caliper 5 according to the invention in which the characteristic braking value sensor 29, advantageously a force sensor, is disposed on an axially internal face of a caliper finger 37 opposite a backplate 43 of the second brake pad 17.2. The sensor 29 is applied by the caliper finger 37 (rigid mounting) or by elastic means (suspended mounting) to the axially external face of the second brake pad 17.2. In other words, the sensor 29 is fixed directly or indirectly, rigidly or elastically, to at least one of the caliper fingers 37. During braking, the sensor 29 is compressed between the second brake pad 17.2, typically its backplate 43, and the caliper nose 11.

[0035] In the example illustrated in [Fig.3], the sensor 29 is carried by a tangential cross member 45 anchored on the stirrup fingers 37.

[0036] In a first embodiment the cross member 45 has a rigidity equivalent to that of the stirrup fingers 37 and the arch 9.

[0037] The sensor 29 in rigid mounting, on caliper finger 37 and / or on the cross member 45, directly measures the braking force.

[0038] In a second embodiment the crossbar 45 is elastic.

[0039] In the case of a suspended mounting on a caliper finger 37 and / or on the cross member 45, the force exerted on the sensor 29 is less than the braking force absorbed by the caliper nose 11. The elasticity and / or rigidity of the elastic means for suspending the sensor 29 are preferably chosen so as to always maintain mechanical contact between the sensor 29 and the support plate 43 of the brake pad 17.2, thereby reducing the force exerted on the sensor, at least for high braking forces of the brake 1, and having a definite and / or determinable function between the values ​​measured by the sensor 29 and the corresponding values ​​of the braking force. The processing circuit 33, advantageously the control circuit of the brake 1, performs any corrections and / or conversions that may be necessary to determine the actual braking force from the measured value.In the first example, the conversion and / or correction of the measured value to the actual value is carried out by applying the laws of physics, taking into account the elasticity and opening of the caliper 5 when braking force is applied. In the second example, a conversion table (LUT in Anglo-Saxon terminology) is used, the values ​​of which are obtained by calculation or experimental measurement.

[0040] It is understood that a caliper comprising a plurality of identical or different sensors does not fall outside the scope of the present invention.

[0041] Figure 4 illustrates the preferred example of the braking method according to the invention.

[0042] At 47, the sensor 29 measures a characteristic braking value, typically a force, and transmits the measured value to the processing circuit 33.

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] In 49, the processing circuit 33 performs any necessary corrections to deduce the corrected value from the measured value, advantageously the actual value of the braking force. Alternatively, the correction and / or conversion of the measured value is performed directly at the sensor 29. In 51, the processing circuit 33 receives and / or generates a setpoint value for the characteristic braking value, advantageously the braking force exerted by the vehicle's brake 1, as a function of a desired vehicle speed and / or trajectory. The setpoint value advantageously takes into account the anti-lock braking system and the vehicle's trajectory control functions. In 53, the processing circuit 33 compares the measured and corrected value to the brake control setpoint value 1. The electrical control 55 of the motor 21 ensures the recoil of the first brake pad 17.1 relative to the brake disc, if the measured and corrected force exceeds the setpoint force and, on the contrary, the advance of the first pad 17.1 in the direction of the brake disc, if the measured and corrected force is less than the setpoint force. The process in [Fig.4] is advantageously carried out in a closed loop with a frequency sufficient to ensure the safety and stability of the vehicle as well as the comfort of the passengers. It is understood that the invention also applies to fixed caliper brakes. LIST OF DIGITAL REFERENCES 1 brake 3 clevis 5 caliper 7 actuator area 9 arch 11 caliper nose 13 area axially opposite to the actuator area 15 brake disc periphery receiving housing 17.1; 17.2 first and second brake shoes 19 geared motor 21 motor 23 speed reducer 25 mechanism for converting rotational motion into translational motion 27 mechanical interface 29 sensor 31 communication means; cable 33 processing circuit 35 cable fastening means 37 caliper fingers 39 caliper finger spacing 41 decorative plate 43 pad support plate 45 cross member 47 measurement 49 correction / conversion 51 brake setpoint value 53 comparison 55 brake motor control

Claims

Demands

1. Brake caliper (5) comprising an actuator zone (7), a radially external arch (9) and an axially opposed zone (13) to the actuator zone (7), together defining a housing (15) for receiving a radially external portion of a brake disc, the arch (9) connecting the actuator zone (7) with the axially opposed zone (13), the actuator zone (7) being provided with a first brake pad (17.1) comprising a friction lining and an actuator comprising a motor (21) comprising a rotor and a mechanism (25) for converting the rotational motion of the rotor into a translational motion of application of the pad (17.1) on the disc, the axially opposed zone (13) comprising a second brake pad (17.2) equipped with a friction lining, the caliper (5) further comprising a sensor (29) of a characteristic braking value characterized in that the sensor (29) of a characteristic braking value is disposed in the axially opposite zone (13).

2. Stirrup (5) according to claim 1 characterized in that the sensor (29) is a force sensor.

3. Stirrup (5) according to claim 2 of characterized in that the sensor (29) is a strain gauge.

4. Stirrup (5) according to any one of the preceding claims characterized in that it comprises a cable (31) connected to the sensor (29) and supports (35) for the cable (29) arranged on the outside of the stirrup (5).

5. Caliper (5) according to claim 4 characterized in that the cable (31) is connected to a brake processing and / or control circuit (33).

6. Stirrup (5) according to any one of the preceding claims characterized in that the axially opposite area (13) to the actuator area (7) comprises stirrup fingers (11) and in that the sensor (29) is carried by a stirrup finger (11).

7. Stirrups (5) according to any one of the preceding claims characterized in that the axially opposite area (13) to the actuator area (7) comprises stirrup fingers (11) and a space (39) between the stirrup fingers (11), in that a cross member (45) is disposed in said space (39) and in that the sensor (29) is carried by said cross member (45).

8. Caliper (5) according to any one of the preceding claims characterized in that it comprises elastic means for applying the sensor (29) to the second brake pad (17.2).

9. Caliper (5) according to claim 8 characterized in that the elastic means apply the sensor (29) to a support plate (43) of the second brake pad (17 2).

10. Vehicle brake characterized in that it comprises a caliper (5) according to any one of the preceding claims.

11. Vehicle brake according to claim 10 characterized in that it comprises a yoke (3) and a floating caliper (5).

12. Braking system characterized in that it comprises a caliper (5) according to any one of claims 1 to 9 and data processing means receiving a characteristic value of the braking from the sensor (29) and ensuring a correction of the measured value and a comparison of the corrected value with a setpoint value.

13. Braking system according to claim 12 characterized in that it comprises means for controlling the brake as a function of the difference between the corrected value and the setpoint value.

14. Braking system according to claim 12 or 13 characterized in that the measurement (47), correction (49) and control (55) are ensured in closed loop.

15. A method for braking a motor vehicle comprising a first step of measuring a characteristic braking value, a second step of correcting the measured value, a step of developing a setpoint value, a step of comparing the setpoint value with the measured and corrected value and a braking control (55) based on the result of the comparison (53) of the corrected measured value and the setpoint value.

16. Method according to claim 15 characterized in that the characteristic value of the braking is a braking force.

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