Brake calliper

Abstract

A brake calliper (20) configured to move one or more brake pads into and out of contact with a brake 5 disc (30), wherein the brake calliper (20) includes a variable reluctance pickup sensor (22) including: a permanent magnet (24); a ferromagnetic pole piece (26); and a coil of wire (28) at least partially surrounding the ferromagnetic pole piece (26); 10 a disc brake (10) including such a brake calliper (20); and a vehicle including one or more disc brakes (10) including a such brake calliper (20).

Description

[0001] ©

[0002] Haldex Aktiebolag

[0003] MSP Ref: 48622 PT- WO Nk / zi

[0004] BRAKE CALLIPER

[0005] FIELD

[0006] The present invention relates to a brake calliper, a disc brake including the brake calliper, and a vehicle including the disc brake.

[0007] BACKGROUND

[0008] Disc brakes are commonly used as the braking mechanisms in vehicles. For example, cars, motorcycles and trucks may include a disc brake for one wheel, a pair of wheels (e.g. the front wheels) or all of the wheels. Typically, a brake disc, or rotor, rotates on the wheel axle with the wheel. A pair of brake pads are positioned on either side of the brake disc. Each brake pad may include a high-friction surface adjacent the brake disc. The brake pads can be moved into contact with the brake disc, thereby causing friction. This hinders the rotation of the wheel axle, on which both the brake disc and the wheel are mounted. The speed of rotation of the wheel is therefore slowed, in order to slow or halt the vehicle.

[0009] The friction between the brake pads and the brake disc transforms the kinetic energy into thermal energy, which causes the disc brake to heat up. Therefore, it can be desirable to provide means of dissipating this heat. For example, the brake disc can be “double skinned”, with cooling fins connecting the two skins of the brake disc. The cooling fins may increase the surface area of the brake disc, thereby transferring more heat away from the brake disc by convection.

[0010] Disc brakes also typically include a brake calliper, which is used to control the movement of the brake pads into and out of contact with the brake disc. The brake calliper may be configured to fit over the brake disc, to act as a clamp that pushes the brake pads into contact with the brake disc. The brake calliper may operate hydraulically, mechanically, pneumatically and / or electromagnetically. For example, the brake calliper may include a hydraulically actuated piston within a cylinder. When the driver brakes (e.g. by stepping on the brake pedal), brake fluid may create hydraulic pressure on the piston in the brake calliper, which causes the brake pads to clamp against the brake disc.

[0011] A wheel end unit provides additional functionality to the vehicle, for example the wheel end unit may include a wheel speed sensor and / or pad wear sensors, to monitor wheel end data. The sensors provided in the wheel end unit require a power source. However, additional wires and / or components may interfere with the operation of the disc brake, or with other components of the vehicle. It may also be desirable for other electrical components adjacent the brake calliper to be provided. However, providing energy to those components can be problematic, also due to wires or components interfering with the operation of the disc brake or other components.

[0012] BRIEF DESCRIPTION OF THE INVENTION

[0013] There is provided a brake calliper configured to move one or more brake pads into and out of contact with a brake disc, wherein the brake calliper includes a variable reluctance pickup sensor including: a permanent magnet; a ferromagnetic pole piece; and a coil of wire at least partially surrounding the ferromagnetic pole piece.

[0014] The brake calliper may include an electronic circuit in electrical communication with the coil of wire, the electronic circuit being supplied with electrical energy from the variable reluctance pick up sensor.

[0015] The electronic circuit may include one or more electronic components.

[0016] The one or more electronic components may be configured to determine the speed of rotation of the brake disc.

[0017] The one or more electronic components may include a pad wear sensor that is configured to monitor the wear of the one or more brake pads.

[0018] The one or more electronic components may include a temperature sensor that is configured to monitor the temperature of the one or more brake pads and / or the brake disc.

[0019] The one or more electronic components may include a vibration sensor that is configured to monitor the vibration of the one or more brake pads and / or the brake disc.

[0020] The one or more electronic components may include a capacitor or battery configured to store electrical energy from the variable reluctance pickup sensor.

[0021] The one or more electronic components may include a transmitter that is configured to transmit information from the brake calliper to a control unit of a vehicle.

[0022] The transmitter may be configured to transmit the speed of rotation of the brake disc. 48622 PT- WO Nk / zi ©

[0023] The transmitter may be configured to transmit information from other electronic components.

[0024] There is also provided a disc brake including a brake calliper as described herein and a brake disc, wherein the brake disc includes a plurality of ferromagnetic protrusions, and wherein the variable reluctance pickup sensor is configured to generate a voltage based on the movement of the plurality of protrusions as the brake disc rotates.

[0025] The protrusions may be teeth arranged on the outer surface of the brake disc.

[0026] The protrusions may be cooling fins.

[0027] The brake disc may include two plates separated by the cooling fins.

[0028] There is also provided a vehicle including one or more disc brakes including a brake calliper as described herein.

[0029] A vehicle wherein the brake calliper may be configured to determine the speed of rotation of a wheel of the vehicle.

[0030] A vehicle wherein the vehicle is a trailer, in particular a semi-trailer.

[0031] Use of a brake disc in a disc brake, in particular to generate a voltage in the variable reluctance pickup sensor.

[0032] Use of a brake pad in a disc brake, in particular to be moved into and out of contact with a brake disc.

[0033] 48622 PT- WO Nk / zi ©

[0034] BRIEF DESCRIPTION OF THE FIGURES

[0035] In orderthat the present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0036] FIGURE 1 is a perspective view of a portion of a disc brake, including a brake calliper that includes a variable reluctance pickup sensor; FIGURE 2 is a front view of the variable reluctance pickup sensor of FIGURE 1 , with a toothed gear; and

[0037] FIUGRE 3 is a perspective view of a portion of the disc brake of FIGURE 1 , wherein the brake calliper includes an electronic circuit.

[0038] DETAILED DESCRIPTION OF THE DISCLOSURE

[0039] Figure 1 illustrates a portion of a disc brake 10 including a brake calliper 20 and a brake disc 30. The disc brake 10 may also include one or more brake pads, which are not shown in Figure 1. Figure 1 illustrates the brake disc 30 and a portion of the brake calliper 20. In use, the brake disc 30 may be mounted on a wheel axle on which a wheel is also mounted.

[0040] The brake calliper 20 may include any of the features found in existing brake callipers, for example as described above. The brake calliper 20 may be configured to move one or more brake pads into and out of contact with the brake disc 30. When the brake pad(s) are brought into contact with the brake disc 30, friction may be caused. This may hinder the rotation of the wheel axle on which the brake disc 30 is mounted, thereby slowing the speed of rotation of the wheel or keeping the wheel stationary. The brake calliper 20 may operate hydraulically, mechanically, pneumatically and / or electromagnetically. For example, the brake calliper 20 may include a hydraulically actuated piston within a cylinder. When the driver brakes (e.g. by stepping on the brake pedal), brake fluid may create hydraulic pressure on the piston in the brake calliper 20, which causes the brake pads to clamp against the brake disc 30.

[0041] As shown, the brake calliper 20 may include a sensor 22. The sensor may be a variable reluctance pickup sensor 22. Figure 2 illustrates a variable reluctance pickup sensor 22 in more detail. A variable reluctance pickup sensor 22 is a sensor that is able to generate a voltage as a toothed gear 40 rotates. Figure 2 illustrates the variable reluctance pickup sensor 22 and the toothed gear 40. If the spacing of the teeth on the toothed gear 40 is known, then the voltage generated by the variable reluctance pickup sensor 22 may be used to determine the speed of rotation of the toothed gear 40, as explained below.

[0042] As shown in Figure 2, the variable reluctance pickup sensor 22 may include a permanent magnet 24. The variable reluctance pickup sensor 22 may include a ferromagnetic pole piece 26. The ferromagnetic pole piece 26 may be made from any suitable ferromagnetic material, such as iron. As shown in Figure 2, the permanent magnet 24 and the ferromagnetic pole piece 26 may be adjacent one another, such that a magnetic field is created through and around the ferromagnetic pole piece 26. The variable reluctance pickup sensor 22 may include a coil of wire 28. The coil of wire 28 may surround at least a portion of the ferromagnetic pole piece 26. For example, and as shown in Figure 2, the ferromagnetic pole piece 26 may have an elongated shape. The coil of wire 28 and the elongated ferromagnetic pole piece 26 may have a common axis, such that the wire 28 forms a coil extending along the ferromagnetic pole piece 26.

[0043] Due to the presence of the magnetic field and the coil of wire 28, a current will be generated if a ferromagnetic material moves within the magnetic field. For example, if a toothed gear 40 is placed adjacent the ferromagnetic pole piece 26, as shown in Figure 2, then the rotation of the toothed gear 40 within the magnetic field will cause a voltage to be induced in the coil of wire 28. This is because the air gap between the toothed gear 40 and the pole piece 26 will vary in size as the toothed gear 40 rotates. This causes the reluctance to change, which causes a varying amount of current to be induced in the coil 28. In particular, when a tooth 42 passes adjacent the ferromagnetic pole piece 26, then the air gap between the toothed gear 40 and the ferromagnetic pole piece 26 will be smaller. This causes a larger current to be induced in the coil 28. Conversely, when a gap 44 between the teeth 42 of the toothed gear 40 passes adjacent the ferromagnetic pole piece 26, then the air gap between the toothed gear 40 and the ferromagnetic pole piece 26 will be larger. This results in a smaller current being induced in the coil 28.

[0044] Therefore, as the toothed gear 40 rotates, a pulsed voltage will be induced in the coil 28, with each pulse corresponding to a tooth 42 of the toothed gear 40 passing the sensor 22.

[0045] If the number of teeth 42 on the toothed gear 40 is known, then the pulsed voltage signal can be used to determine the speed of rotation of the toothed gear 40.

[0046] As mentioned above, Figure 1 depicts a brake calliper 20 including a variable reluctance pickup sensor 22. Instead of a toothed gear 40, Figure 1 shows the variable reluctance pickup sensor 22 of the brake calliper 20 being used in combination with a brake disc 30. The brake disc 30 may be at least partially made from a ferromagnetic material. Therefore, a brake disc 30 may be used in place of the toothed gear 40 described above, in order to generate current from the variable reluctance pickup sensor 22 in the brake calliper 20.

[0047] As shown in Figure 1 , the brake calliper 20 may be used with a brake disc 30 that includes a plurality of cooling fins 32. The brake disc 30 may be a “double skinned” brake disc 30. In other words, the brake disc 30 may include two plates, or skins, 36 connected by a plurality of cooling fins 32, as shown in Figure 1. The cooling fins 32 may be made from a ferromagnetic material. The cooling fins 32 may be configured to allow heat to dissipate from the brake disc 30. In particular, and as explained above, the cooling fins 32 may increase the surface area of the brake disc 30, thereby increasing the area of the brake disc 30 that is exposed to air. This allows heat that is generated in the brake disc 30 due to the friction with the brake pads to efficiently dissipate.

[0048] The cooling fins 32 may act as the teeth 42 for the variable reluctance pickup sensor 22. That is, instead of using the teeth 42 of a toothed gear 40 to generate voltage, the variable reluctance pickup sensor 22 may generate voltage using the cooling fins 32 of the brake disc 30. As the brake disc 30 rotates, the air gap between the brake disc 30 and the ferromagnetic pole piece 26 of the variable reluctance pickup sensor 22 will vary, due to the presence of the cooling fins 32. The air gap will be smaller as a cooling fin 32 passes adjacent the ferromagnetic pole piece 26, and the air gap will be larger as a gap 34 between cooling fins 32 passes adjacent the ferromagnetic pole piece 26. Therefore, as the brake disc 30 rotates, the reluctance will vary, which will cause a current to be generated. In this way, the variable reluctance pickup sensor 22 in the brake calliper 20 may generate an analogue voltage output signal in the coil of wire 28.

[0049] As shown in Figure 3, the brake calliper 20 may include an electronic circuit 50. The electronic circuit 50 may be part of a wheel end unit. The electronic circuit 50 may be in electrical communication with the coil of wire 28, such that the electronic circuit 50 receives the analogue voltage signal from the coil of wire 28 of the sensor 22. The electronic circuit may be powered by the output of the variable reluctance sensor 22.

[0050] The electronic circuit 50 may be configured to determine the speed of rotation of the brake disc 30. If the number of cooling fins 32 in the brake disc 30 is known, then the voltage signal may be used to determine the speed of rotation of the brake disc 30, because the voltage signal may include a series of pulses, with each pulse corresponding to one of the cooling fins 32. Therefore, the number of pulses in a minute will correspond to the number of cooling fins 32 passing the ferromagnetic pole piece 26 in a minute. If the number of cooling fins 32 in the brake disc 30 is known, then the voltage signal may be used to determine the number of revolutions of the brake disc 30 per minute.

[0051] Since the brake disc 30 may be mounted on the same axle as a wheel of the vehicle, the brake disc 30 may rotate at the same speed as the wheel of the vehicle. Therefore, the voltage signal may be used to determine the speed of rotation of the wheel of the vehicle.

[0052] This may be advantageous, because the use of a variable reluctance pickup sensor 22 in the brake calliper 20 may allow the speed of rotation of the wheel to be monitored, without requiring the need for an external power source. This avoids the need for any additional components, which could interfere with the operation of the disc brake 10. In this way, the brake calliper 20 provides a simple means for monitoring the speed of rotation of a wheel, without requiring an external power source.

[0053] As explained above, Figure 1 illustrates a brake disc 30 having cooling fins 32 that are used to induce the voltage. However, it will be appreciated that the brake calliper 20 could be used with any brake disc 30 having a series of ferromagnetic protrusions. The protrusions could be internal to the brake disc 30, such as the cooling fins 32 shown in Figure 1 . Alternatively, the brake disc 30 could include external protrusions or teeth, such as a series of teeth that surround the outer surface of the brake disc 30. In other words, the brake disc 30 may be a toothed gear 40.

[0054] The disc brake 10 may include one or more electronic components 60. The electronic components 60 may be part of the wheel end unit. The electronic components 60 may be positioned on or near, connected to or associated with, the brake calliper 20. The one or more electronic components 60 may be configured to receive power from the electronic circuit 50. In this way, the variable reluctance pickup sensor 22 in the brake calliper 20 may be used to generate a voltage that is supplied to power the one or more electronic components 60 . The brake calliper 20 may therefore be advantageous, because the brake calliper 20 may be able to provide additional functions, without the need for an external power source which, as mentioned above, traditionally requires wired connections.

[0055] For example, the one or more electronic components 60 may include a pad wear sensor. The pad wear sensor may be configured to monitor the wear of one or more brake pads. The pad wear sensor may be configured to provide an indication of whether the wear on one or more of the brake pads exceeds a predetermined limit.

[0056] Additionally or alternatively, the one or more electronic components 60 may include a temperature sensor. The temperature sensor may be configured to measure the temperature of the brake disc 30 and / or the brake pads. In this way, the brake calliper 20 can be used to monitor the temperate of the components of the disc brake 10, to ensure that the disc brake 10 is not overheating.

[0057] Additionally or alternatively, the one or more electronic components 60 may include a vibration sensor. For example, the vibration sensor may be a knock sensor or a piezo sensor. The use of a vibration sensor may be advantageous, since monitoring vibrations within the disc brake 10 may provide an indication of whether or not the disc brake 10 is operating correctly.

[0058] Additionally or alternatively, the one or more electronic components 60 may include one or more energy storage devices, for example one or more batteries and / or capacitors. For example, the electronic circuit 50 may include a low capacity battery or a super capacitor. The inclusion of a battery or capacitor may allow the brake calliper 20 to store electrical energy from the variable reluctance pickup sensor 22. This may allow any of the one or more electronic components 60 to continue operating, even when the voltage generated by the variable reluctance pickup sensor 22 is low, and / or when voltage is no longer being generated by the variable reluctance pickup sensor 22. For example, the inclusion of an energy storage device may allow one or more of the electronic components 60 to continue operation for a period of time while the associated wheel (and / or the vehicle) is stationary.

[0059] The one or more electronic components 60 may include a transmitter. The transmitter may be configured to transmit information to a control unit of the vehicle. For example, the transmitter may be a radio frequency transmitter. The transmitter may be configured to communicate information from one or more other electronic components 60 in the brake calliper 20. For example, the transmitter may be configured to transmit information about one or more of the speed of rotation of the wheel, the wear of the brake pad(s), the temperature or the vibration. It will be appreciated that the brake calliper 20 could include any suitable electronic components 60, such as sensors, transmitters, receivers and control units.

[0060] The brake calliper 20 may be used in a vehicle that includes a plurality of brake callipers 20. For example, one brake calliper 20 may be provided for each wheel of the vehicle. The vehicle may include a receiver that is configured to receive information from the transmitters of each of the brake callipers 20. In this way, the receiver may collate the information about the operation of each of the disc brakes 10. Comparisons between the operations of the disc brakes 10 may be made, to identify whether any of the disc brakes 10 are faulty.

[0061] Additionally or alternatively, the electronic circuit 50 may be configured to provide power to one or more electronic components that are external to the brake calliper 20. For example, the electronic circuit 50 may be configured to provide power to a pad wear sensor, a temperature sensor, a vibration sensor, or any other electronic component that may not be part of the brake calliper 20.

[0062] The brake calliper 20 may include a plurality of variable reluctance pickup sensors 22. When the brake calliper 20 is adjacent a brake disc 30, each variable reluctance pickup sensor 22 may be positioned with the ferromagnetic pole piece adjacent one of the teeth 42 or cooling fins 32 of the brake disc 30. The use of a plurality of variable reluctance pickup sensors 22 may increase the amount of voltage generated by each rotation of the brake disc 30. However, it will be appreciated that sufficient voltage to operate the brake calliper 20 may be provided by a single variable reluctance pickup sensor 22. It will also be appreciated that the amount of voltage generated can be modified by adapting one or more properties of the variable reluctance pickup sensor 22, such as the size and material of the permanent magnet 24 and the ferromagnetic pole piece 26, and the number of turns in the coil 28. These properties may be selected to provide a desired voltage.

[0063] Through the use of the variable reluctance pickup sensor 22, the brake calliper 20 is able to generate a voltage signal from the brake disc 30. The brake calliper 20 may also be able to monitor information about the operation of the disc brake 10, such as the speed of rotation of the wheel, the wear, the temperature and / or the vibration. The brake calliper 20 may also be able to communicate some or all of this information to a control unit of the vehicle. In this way, the brake calliper 20 may monitor the operation of the disc brake 10, and may communicate information about the operation of the disc brake 10 to a control unit of the vehicle. This may improve the safety of the disc brake 10, by allowing the vehicle and / or the user of the vehicle to promptly identify any issues with the operation of the disc brake 10. Identifying problems with the disc brake 10 early may allow the disc brake 10 to be repaired, rather than requiring a full replacement when the disc brake 10 has become completely inoperable, which may also provide environmental benefits. By providing a means of generating voltage (i.e. the variable reluctance pickup sensor 22) within the brake calliper 20, the brake calliper 20 is able to provide any or all of the additional functions described above, without requiring an external power source. Therefore, the brake calliper 20 is simple in design, and avoids the need for additional wiring that could interfere with the operation of the disc brake 10.

[0064] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0065] The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

[0066] Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

[0067] Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents.

Claims

CLAIMS1 . A brake calliper configured to move one or more brake pads into and out of contact with a brake disc, wherein the brake calliper includes a variable reluctance pickup sensor including: a permanent magnet; a ferromagnetic pole piece; and a coil of wire at least partially surrounding the ferromagnetic pole piece.

2. A brake calliper according to claim 1 , further including an electronic circuit in electrical communication with the coil of wire, the electronic circuit being supplied with electrical energy from the variable reluctance pick up sensor.

3. A brake calliper according to claim 2, wherein the electronic circuit includes one or more electronic components.

4. A brake calliper according to claim 3, wherein the one or more electronic components are configured to determine the speed of rotation of the brake disc.

5. A brake calliper according to claim 3 or 4, wherein the one or more electronic components include a pad wear sensor that is configured to monitor the wear of the one or more brake pads.

6. A brake calliper according to claim 3 to 5, wherein the one or more electronic components include a temperature sensor that is configured to monitor the temperature of the one or more brake pads and / or the brake disc.

7. A brake calliper according to any of claims 3 to 6, wherein the one or more electronic components include a vibration sensor that is configured to monitor the vibration of the one or more brake pads and / or the brake disc.

8. A brake calliper according to any of claims 3 to 7, wherein the one or more electronic components include a capacitor or battery configured to store electrical energy from the variable reluctance pickup sensor.

9. A brake calliper according to any of claims 3 to 8, wherein the one or more electronic components include a transmitter that is configured to transmit information, in particular from the brake calliper and / or to a control unit of a vehicle.

10. A brake calliper according to claim 9, in particular when directly or indirectly dependent on claim 4, wherein the transmitter is configured to transmit the speed of rotation of the brake disc.

11. A brake calliper according to claim 9 or 10, in particular when directly or indirectly dependent on claim 4, wherein the transmitter is configured to transmit information from other electronic components, in particular the wear of the one or more brake pads and / or he temperature of the one or more brake pads and / or the brake disc and / or the vibration of the one or more brake pads and / or the brake disc.

12. A disc brake including the brake calliper according to any of the preceding claims and a brake disc, wherein the brake disc includes a plurality of ferromagnetic protrusions, and wherein the variable reluctance pickup sensor is configured to generate a voltage based on the movement of the plurality of protrusions as the brake disc rotates.

13. A disc brake according to claim 12, wherein the protrusions are teeth arranged on the outer surface of the brake disc.

14. A disc brake according to claim 12 or 13, wherein the protrusions are cooling fins.

15. A disc brake according to claim 14, wherein the brake disc includes two plates separated by the cooling fins.

16. A vehicle including one or more disc brakes according to any of claims 12 to 15.

17. A vehicle according to claim 16, wherein the brake calliper is configured to determine the speed of rotation of a wheel of the vehicle.

18. A vehicle according to claim 17, wherein the vehicle is a trailer, in particular a semi-trailer.

19. Use of a brake disc in a disc brake according to any of the claims 12 to 15, in particular to generate a voltage in the variable reluctance pickup sensor.

20. Use of a brake pad in a disc brake according to any of claims 12 to 15, in particular to be moved into and out of contact with a brake disc.

Images