EP4627307A1

EP4627307A1 - Force sensor apparatus with a spherical force interface

Info

Publication number: EP4627307A1
Application number: EP23847661.8A
Authority: EP
Inventors: Jan-Willem Sloetjes; Frank Hendri JACOBS; Sander Johannes Gerardus PAS
Original assignee: Sensata Technologies Inc
Current assignee: Sensata Technologies Inc
Priority date: 2022-12-10
Filing date: 2023-12-10
Publication date: 2025-10-08
Also published as: CN120548460A; WO2024124225A1

Abstract

In a particular embodiment, a force sensor apparatus is disclosed that includes a force-compliant element that deforms in response to applications of forces to the force sensor apparatus. The force-compliant element has a bottom portion with an outer rim that surrounds a force interface. In this embodiment, the outer rim and the force interface extend outward from the bottom portion. The force interface forms a solid, spherical shape centered at a center line of the force-compliant element. The spherical force interface is configured to receive an application of load force and distribute the load force to the force-compliant element. The apparatus also includes one or more sensing elements coupled to the force-compliant element and configured to generate a signal indicating the degree that the force-compliant element deforms in response to the applications of forces to the force sensor apparatus.

Description

FORCE SENSOR APPARATUS WITH A SPHERICAL FORCE INTERFACE

FIELD OF THE TECHNOLOGY

[0001] The subject disclosure relates to a force sensor apparatus with a spherical force interface.

BACKGROUND

[0002] Force sensors are often used to control or regulate a force that is applied to a component. In one type of force sensor, the force sensor is positioned in such a way that forces to be measured act on the sensor. The force sensor may be configured to transform a measurement of forces into an electrical signal for further use in the control or regulation of the forces. This type of force sensor may be used in a variety of applications, such as for measuring braking force of electromechanical brakes in automobiles. For example, a force- compliant element of the force sensor may be coupled to some component of the braking system and as forces are applied, the force-compliant element temporarily deforms. In this example, the strain on the force-compliant element may be measured and used to generate an electrical signal that is indicative of the forces acting on the component of the braking system.

SUMMARY

[0003] In a particular embodiment, a force sensor apparatus is disclosed that includes a force- compliant element that deforms in response to applications of forces to the force sensor apparatus. The force-compliant element has a bottom portion with an outer rim that surrounds a force interface. In this embodiment, the outer rim and the force interface extend outward from the bottom portion. The force interface forms a solid, spherical shape centered at a center line of the force-compliant element. The spherical force interface is configured to receive an application of load force and distribute the load force to the force-compliant element. The apparatus also includes one or more sensing elements coupled to the force- compliant element and configured to generate a signal indicating the degree that the force- compliant element deforms in response to the applications of forces to the force sensor apparatus.

[0004] In another embodiment, a method of assembling a force sensor apparatus is disclosed that includes attaching a printed circuit board (PCB) having electrical components to a support structure. The method also includes electrically coupling the electrical components of the PCB to at least two sensing elements on a force-compliant element. In this example embodiment, the at least two sensing elements are configured to measure forces applied to the force sensor apparatus. The method also includes attaching the support structure to a force-compliant element having a bottom portion with an outer rim that surrounds a force interface. In this embodiment, the outer rim and the force interface extend outward from the bottom portion. The force interface forms a solid, spherical shape centered at a center line of the force-compliant element. The spherical force interface is configured to receive an application of load force and distribute the load force to the force-compliant element.

[0005] The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary' embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 A is a diagram illustrating a force sensor apparatus with a ring-shaped force interface;

[0007] FIG. IB is a diagram illustrating radial movement of a force-compliant element of the force sensor apparatus of FIG. 1A;

[0008] FIG. 2A is a diagram illustrating a side view of a force-compliant element with a ringshaped force interface;

[0009] FIG. 2B is a diagram illustrating an exploded view' of another force sensor apparatus that includes the force-compliant element of FIG. 2A;

[0010] FIG. 2C is a diagram illustrating function test results for lubricated and non-lubricated ring-shaped force interfaces;

[0011] FIG. 3 is a diagram illustrating a side view of a force-compliant element with a spherical force interface according to at least one embodiment of the present disclosure; [0012] FIG. 4A is a diagram illustrating Von Mises stresses on a ring-shaped force interface; [0013] FIG. 4B is a diagram illustrating Von Mises stresses on the spherical shaped interface of FIG. 3;

[0014] FIG. 5 A is a diagram illustrating a comparison of FT data of a non-lubricated force interface of a ring-shaped force interface;

[0015] FIG. 5B is a diagram illustrating a comparison of FT data of a non-lubricated force interface of the spherical force interface of FIG. 3;

[0016] FIG. 5C is a diagram illustrating a comparison of FT data of a lubricated force interface of a ring-shaped force interface;

[0017] FIG. 5D is a diagram illustrating a comparison of FT data of a lubricated force interface of the spherical force interface of FIG. 3; [0018] FIG. 6 is a diagram illustrating a graph indicating the accuracy of the spherical force interface with non-linearity correction;

[0019] FIG. 7A is a diagram illustrating an example e-pedal force sensor apparatus with a spherical force interface according to at least one embodiment of the present disclosure; [0020] FIG. 7B is a diagram illustrating another view of the e-pedal force sensor apparatus of FIG. 7A;

[0021] FIG. 7C is a diagram illustrating a cross-section view of the e-pedal force sensor apparatus of FIG. 7A;

[0022] FIG. 8A is a diagram illustrating an example e-caliper force sensor apparatus with a spherical force interface according to at least one embodiment of the present disclosure. [0023] FIG. 8B is a diagram illustrating another view of the e-caliper force sensor apparatus of FIG. 8A;

[0024] FIG. 8C is a diagram illustrating a cross-section view of the e-caliper force sensor apparatus of FIG. 8A;

[0025] FIG. 9A is a diagram illustrating an example e-drum force sensor apparatus with a spherical force interface according to at least one embodiment of the present disclosure. [0026] FIG. 9B is a diagram illustrating another view of the e-drum force sensor apparatus of FIG. 9A;

[0027] FIG. 9C is a diagram illustrating a cross-section view of the e-drum force sensor apparatus of FIG. 9A;

[0028] FIG. 10 is a flowchart to illustrate an implementation of a method for assembling a force sensor apparatus according to embodiments of the present disclosure; and

[0029] FIG. 11 is a flowchart to illustrate another implementation of a method for assembling a force sensor apparatus according to embodiments of the present disclosure.

DETAILED DESCRIPTION

[0030] The terminology used herein for the purpose of describing particular examples is not intended to be limiting for further examples. Whenever a singular form such as “a”, “an” and “the” is used and using only a single element is neither explicitly or implicitly defined as being mandatory, further examples may also use plural elements to implement the same functionality. Likewise, when a functionality is subsequently described as being implemented using multiple elements, further examples may implement the same functionality using a single element or processing entity . It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including”, when used, specify the presence of the stated features, integers, steps, operations, processes, acts, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, acts, elements, components and/or any group thereof. [0031] It will be understood that when an element is referred to as being “connected” or “coupled” to another element, the elements may be directly connected or coupled or via one or more intervening elements. If two elements A and B are combined using an “or”, this is to be understood to disclose all possible combinations, i.e., only A, only B, as well as A and B. An alternative wording for the same combinations is “at least one of A and B”. The same applies for combinations of more than two elements.

[0032] Accordingly, while further examples are capable of various modifications and alternative forms, some particular examples thereof are shown in the figures and will subsequently be described in detail. However, this detailed description does not limit further examples to the particular forms described. Further examples may cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. Like numbers refer to like or similar elements throughout the description of the figures, which may be implemented identically or in modified form when compared to one another while providing for the same or a similar functionality.

[0033] The function of a pressure sensor is to transform the physical “fluid pressure” into a ratio-metric output voltage. This is achieved by using micro-fused strain gauges (or any other suitable technology) to measure the strain field change on a sensing element due to the applied pressure. The same (MSG) technology can be used to measure forces, as an applied force will also result into a strain field change on the sensing element of the sensor.

[0034] The main difference between pressure sensors and force sensors is that pressure is a scalar and force is a vector. Since force is a vector, the force and support interfaces are much more important, as they could impact the accuracy of the sensor. With the current trend of force sensors needing to become smaller for cost and integration reasons, this is becoming more and more an issue.

[0035] For most application, it’s important to measure the axial applied load and sensor should not measure parasitic forces in radial direction. For an 25kN EMB ring sensor, there was always about l%Fs hysteresis (so the maximum sensor output delta between upwards and downwards force curve). For the next Generation EMB sensor, the forces went up to 65kN. Also the sensor had to become smaller. This resulted into 5%Fs hysteresis. The hysteresis is mainly caused by the friction coefficient in the force interface. The friction will result in radial loading on the bearing/force interface which was also measured by the sensor. By changing the friction coefficient, the amount of hysteresis will change as well, but also the full scale output (for instance reducing the friction will bend the sensing element more resulting into a higher output, therefore Gain shift).

[0036] As will be explained further below, by moving to a ‘'spherical’’ (or Hertzian) force interface, those two problems, “Gain shift” and “hysteresis”, will be solved. With a spherical interface on the center line of the sensing element/sensor, the engagement of the force will start at the center line of the sensor. With this design, there will be no radial loading on the sensor (independent of the friction coefficient) which is positive. Moreover, there will be no radial movement of the sensing element force interface and therefore negligible impact of different friction coefficients on the sensor “Gain”.

[0037] For further explanation, FIG. 1 A sets forth a diagram illustrating a 25kN EMB Ring force sensor apparatus 100 and FIG. IB sets forth a diagram illustrating radial movement of a sensing element of the EMB ring force sensor of FIG. 1A. The apparatus 100 of FIG. 1A includes a force-compliant element 102 configured to deform in response to forces applied to the force sensor apparatus. In a particular embodiment, the force-compliant element 102 has a first surface arranged to receive a first force. The force-compliant element is connected with an interface structure 118 that is arranged to receive a second force opposite in direction to the first force, such that the force-compliant element 102 deforms in response to the application of the first force and the second force on the force sensor apparatus 100. The force-compliant element 102 may a piece of material, such as metal or plastic, that deforms in response to applications of forces. For example, the force-compliant element 102 may be a ring-shaped metal disk.

[0038] The apparatus 100 of FIG. 1A also includes sensing elements (not pictured) coupled to the force-compliant element 102. Each of the sensing elements is configured to generate a signal indicating the degree that the force-compliant element 102 deforms in response to the application of forces on the apparatus 100. The sensing elements may be micro-fused silicon strain gauges (MSG).

[0039] In addition, the apparatus 100 of FIG. 1A also includes a printed circuit board (PCB) (110) on which electrical components (e.g., integrated circuits, and passive elements such as resistors, capacitors, etc.) are positioned and configured to receive the signal from the sensing elements. In the force sensor apparatus (100) of FIG. 1, a support structure 108 has a surface on which the PCB 110 is coupled. The support structure may be made of many types of material, such as metal and plastic, that is suitable for supporting the PCB 110. In the example of FIG. 1A. the support structure 108 is positioned in a stack of the components of the force sensor apparatus 100 to rest on the force-compliant element 102. The support structure 108 may also include openings (not pictured) through which the components of the PCB may be coupled to the sensing elements. In this example, the openings in the support structure 108 may align with positions of bonding pads on the PCB 110, so that the contacts on the sensing elements may be bonded to the bonding pads on the PCB 110.

[0040] The apparatus 100 of FIG. 1A also includes a sensor housing 112 that covers the PCB 110. The sensor housing 112 is designed to protect the electrical components of the force sensor apparatus 100. The apparatus 100 of FIG. 1A also includes an environmental seal ring 106, which when placed between the sensor housing 112 and the force-compliant element 102, ensures that the internal components of the force sensor apparatus 100 are protected. In the example of FIG. 1A, the environmental seal ring is an O-ring. but readers of the skill in the art will realize that a number of other shapes and configurations, such as D-rings and potting compounds, may be used to provide a seal from the environment. Using an environmental seal may allow the sensor housing to be assembled and sealed to the force- compliant element without having to weld or otherw ise couple the inner rim of the sensor housing to the force-compliant element.

[0041] The apparatus 100 of FIG. 1A also includes an electrical connector assembly that is aligned for positioning within an opening of the sensor housing 1 12. In the example of FIG. 1A, the electrical connector assembly includes a plurality⁷ of electrical connection pins 117 for transmitting a signal to an external component (not pictured). The electrical connector assembly also includes a plurality of mechanical orientation features 119 for aligning the apparatus with an external component (not pictured).

[0042] In addition, the apparatus 100 of FIG. 1A includes an interface structure 118 that distributes a load to the force-compliant element 102 when the interface structure 118 is attached to the force-compliant element 102. In the example of FIG. 1A. the interface structure 118 is a ring or interface ring that when coupled to the force-compliant element 102, evenly distributes the load to the force-compliant element 102, so that the sensing elements can accurately measure the load on the force-compliant element. The interface structure 118 may also be used to create an interface for coupling the force sensor apparatus 100 to a component that provides a force to the force-compliant element 102. For example, the interface structure 118 may be used to fix the apparatus 100 to a caliper of an electromechanical braking system.

[0043] In the example of FIG. 1A, the force-compliant element 102 includes a ring-shaped force interface 105 for coupling to an external component that applies a force or load to be measured. For example, the force-compliant element 102 may be coupled to a piston of the electromechanical braking system. As explained above, the applications of these forces may result in the force-compliant element 102 temporarily deforming. In this example, the sensing elements may generate an electrical signal having properties that are commensurate with the amount of deformation in the force-compliant element 102.

[0044] In the example of FIG. 1A, the ring-shaped force interface 105 is positioned at a diameter away from the center line of the sensor. By increasing the load, the force interface will not only move in axial direction, but also in radial direction. This would mean that also radial forces are acting on the sensing element. The level of this force depends on the friction coefficient (which can vary over life and differ between make site calibration and customer application) which will impact the accuracy of the sensor.

[0045] For further explanation, FIG. 2A sets forth a diagram illustrating a side view of a force-compliant element 202 with a ring-shaped force interface 205. The ring-shaped force interface 205 is the surface for coupling the force-compliant element 202 to an external component that applies a force or load to be measured. The force-compliant element 202 also includes a support surface 203 for coupling to an interface structure of a force sensor apparatus.

[0046] For further explanation, FIG. 2B sets forth a diagram illustrating an exploded view of another force sensor apparatus that includes the force-compliant element of FIG. 2A. The apparatus 200 of FIG. 2B includes many components that are similar to the components of the apparatus 100 of FIG. 1 A but are configured and shaped to create a more cylindricalshaped sensor assembly.

[0047] The apparatus 200 of FIG. 2B includes a force-compliant element 202 arranged to receive oppositely directed forces. In a particular embodiment, the force-compliant element 202 is a component of material, such as metal or plastic, that deforms in response to applications of forces. For example, the force-compliant element 202 may be a buttonshaped metal disk.

[0048] The apparatus 200 of FIG. 2B also includes four sensing elements 204 coupled to the force-compliant element 202. Each of the sensing elements 204 is configured to generate a signal indicating the degree that the force-compliant element 202 deforms in response to the application of oppositely directed forces. These signals from the sensing elements 204 may be transmitted through electrical connections (not shown) to a printed circuit board (PCB) 216 and may be used by the PCB 216 and other components coupled to the PCB. In a particular embodiment, the sensing elements are micro-fused silicon strain gauges (MSG). In order to measure the amount of force applied to the force-compliant element, the sensing elements may be evenly distributed on a circle on a top surface of the force-compliant element 202.

[0049] The PCB 216 includes electrical components (integrated circuits, and passive elements such as resistors, capacitors, etc.) that are positioned and configured to receive the signals from the sensing elements 204.

[0050] In the force sensor apparatus 200 of FIG. 2B, the support structure 208 has a surface on which the PCB 216 is coupled. The support structure may be made of many types of material, such as metal and plastic, that are suitable for supporting the PCB 216. In the example of FIG. 2B, the support structure 208 is positioned in a stack of the components of the force sensor apparatus 200 to rest on the force-compliant element 202. For example, in the assembled state, an outer rim of the support structure 208 is coupled to an outer rim 292 of the force-compliant element 202. The support structure 208 may also include openings (not pictured) through which the components of the PCB may be coupled to the sensing elements.

[0051] In addition, the apparatus 200 of FIG. 2B also includes a sensor housing 212 that covers the PCB 216 and the support structure 208. The sensor housing 212 is designed to protect the electrical components of the force sensor apparatus 200 and receive the counterforce for force measurement. Although not pictured, the apparatus 200 of FIG. 2B may also include an electrical connector that is aligned for positioning within an opening of the sensor housing 212. In the assembled state, an outer rim of the sensor housing 212 is coupled to an outer rim 290 of the force-compliant element 202.

[0052] In the example of FIG. 2A and FIG. 2B, the size of the sensor apparatus was reduced to lower the sensor cost. Also, the full scale application force was increased to 65kN. The results in FIG. 2B indicate approximately 5%Fs hysteresis and 5%Fs Gain shift.

[0053] For further explanation, FIG. 3 sets forth a diagram illustrating a side view of a force- compliant element 302 with a spherical force interface 305. The force-compliant element 302 is configured to deform in response to applications of forces. In the example of FIG. 3, the force-compliant element 302 has a bottom portion 349 with an outer rim 347 that surrounds the force interface 305. The outer rim 347 and the force interface 305 extend outward from the bottom portion 349 and are separated by a gap 345. The force interface 305 forms a solid, spherical shape centered at a center line 330 of the force-compliant element 302. The force interface 305 is configured to receive an application of a load force and distribute the load force to the force-compliant element 302. A center 306 of the force interface 305 is configured to contact with an external component to receive the application of the load force. In a particular embodiment, the force interface includes a flat surface for coupling with the external component. In other embodiments, the force interface includes a parabolic shaped surface for coupling with the external component.

[0054] In contrast to the ring-shaped force interface of FIG. 1A and FIG. 2A which is missing a center, the center 306 of the spherical force interface 305 is solid and continuous that allows the load force to be distributed to the center of the force-compliant element. In an alternative embodiment of force-compliant element with a spherical force interface, the outer rim of the force-complaint element and the force interface extend outward from the bottom portion and are not separated by a gap. In this alternative embodiment, the force interface is connected to and extends from the outer rim of the force-compliant element.

[0055] For further explanation, FIG. 4A sets forth a diagram illustrating Von Mises stresses on a ring-shaped force interface, such as one of the ring-shaped interfaces in FIG. 1 A or FIG. 2A. FIG. 4B sets forth a diagram illustrating Von Mises stresses on a spherical force interface 305 of FIG. 3.

[0056] At low load there will be load at the center line of the sensor with the spherical shaped interface. While increasing the load, the contact area will increase. The radius of the spherical interface is optimized in such a way, that plastic deformation in the force interface will be avoided. It is advantageous to avoid yielding in the rest of the sensor. The moment arm, between force interface and support interface of the spherical shaped interface is larger compared to the ring-shaped force interface.

[0057] For further explanation, FIG. 5 A is a diagram illustrating a comparison of FT data of a non-lubricated force interface of a ring-shaped force interface. FIG. 5B is a diagram illustrating a comparison of FT data of a non-lubricated force interface of the spherical force interface of FIG. 3. FIG. 5C is a diagram illustrating a comparison of FT data of a lubricated force interface of a ring-shaped force interface. FIG. 5D is a diagram illustrating a comparison of FT data of a lubricated force interface of the spherical force interface of FIG.

3.

[0058] For further explanation, FIG. 6 sets forth a diagram illustrating a graph indicating the accuracy of the spherical/Hertzian interface with non-linearity correction. For the spherical/Hertzian interface, the non-linearity can largely be compensated in the ASIC resulting in the following accuracy illustrated in FIG. 6.

[0059] For further explanation, FIG. 7A sets forth a diagram illustrating a e-pedal force sensor apparatus 700 with a spherical force interface 705. FIG. 7B illustrates another view of the pedal force sensor apparatus of FIG. 7A and FIG. 7C sets forth a cross-section view of the pedal force sensor apparatus of FIG. 7A. An automobile electronic pedal (e-pedal) force sensor are designed to measure load applied to the brake, accelerator, and clutch pedals during acceleration, deceleration, and transmission shift events.

[0060] The apparatus 700 includes a force-compliant element 702 arranged to receive oppositely directed forces. In a particular embodiment, the force-compliant element 702 is a component of material, such as metal or plastic, that deforms in response to applications of forces.

[0061] The apparatus 700 also includes sensing elements (not pictured) coupled to the force- compliant element 702. Each of the sensing elements is configured to generate a signal indicating the degree that the force-compliant element 702 deforms in response to the application of oppositely directed forces. These signals from the sensing elements may be transmitted through electrical connections (750) to a printed circuit board (PCB) 710 and may be used by the PCB 710 and other components coupled to the PCB. In a particular embodiment, the sensing elements are micro-fused silicon strain gauges (MSG). In order to measure the amount of force applied to the force-compliant element 702, the sensing elements may be evenly distributed on a circle on a top surface of the force-compliant element 702.

[0062] The PCB 710 includes electrical components (integrated circuits, and passive elements such as resistors, capacitors, etc.) that are positioned and configured to receive the signals from the sensing elements.

[0063] In the force sensor apparatus 700, a support structure 708 has a surface on which the PCB 710 is coupled. The support structure may be made of many types of material, such as metal and plastic, that are suitable for supporting the PCB 710. In this example, the support structure 708 is positioned in a stack of the components of the force sensor apparatus 700 to rest on the force-compliant element 702. For example, in the assembled state, an outer rim of the support structure 708 is coupled to an outer rim 792 of the force-compliant element 702. The support structure 708 may also include openings (not pictured) through which the components of the PCB may be coupled to the sensing elements.

[0064] In addition, the apparatus 700 also includes a sensor housing assembly 761 having a sensor housing 770 that covers the PCB 710 and the support structure 708. The sensor housing 770 is designed to protect the electrical components of the force sensor apparatus 700 and receive the counterforce for force measurement. In the assembled state, an outer rim of the sensor housing 770 is coupled to an outer rim 790 of the force-compliant element 702. The force-compliant element 702 also includes a support surface 754 for coupling to an interface structure and receiving a counter force.

[0065] The sensor housing assembly 761 also includes a sensor cap portion 780 for housing electrical connections 788. The electrical connections 788 are coupled to and receive electrical signals from the electrical components of the PCB. The electrical connections 788 are configured for coupling with an external component and transmitting signals from the PCB to the external component. An environmental seal 799 is positioned between the sensor cap portion 780 and the sensor housing 770.

[0066] The force-compliant element 702 has a bottom portion 749 with an outer rim 747 that surrounds the force interface 705. The outer rim 747 and the force interface 705 extend outward from the bottom portion 749 and are separated by a gap 745. The force interface 705 forms a solid, spherical shape centered at a center line (not pictured) of the force-compliant element 702. The force interface 705 is configured to receive a load force and distribute the load force to the force-compliant element 702. In this example, the force interface 706 includes a parabolic shaped surface for coupling with an external component for receiving the load force.

[0067] For example, the force interface 705 may be coupled to a component of an automobile electronic pedal system, such that the force applied to the component may be measured and reported by the apparatus 700. As can be seen in the example of FIG. 7C, the outer rim 747 of the force-compliant element 702 extends beyond the force interface 705 in a direction perpendicular to a plane parallel to the bottom portion 749 of the force-compliant element. Readers of skill in the art will realize that the force interface may be optimized for particular applications by fine tuning the radius of the spherical shape.

[0068] For further explanation, FIG. 8A sets forth a diagram illustrating a e-caliper force sensor apparatus 800 with a spherical force interface 805. FIG. 8B illustrates another view of the e-caliper force sensor apparatus of FIG. 8A and FIG. 8C sets forth a cross-section view of the e-caliper force sensor apparatus of FIG. 8A. An automobile electro-mechanical caliper brake system (e-caliper) force sensor provides monitoring and control an electro-mechanical caliper brake system.

[0069] The apparatus 800 includes a force-compliant element 802 arranged to receive oppositely directed forces. In a particular embodiment, the force-compliant element 802 is a component of material, such as metal or plastic, that deforms in response to applications of forces. [0070] The apparatus 800 also includes sensing elements (804) coupled to the force- compliant element 802. Each of the sensing elements 804 is configured to generate a signal indicating the degree that the force-compliant element 802 deforms in response to the application of oppositely directed forces. These signals from the sensing elements 804 may be transmitted through electrical connections (not shown) to a printed circuit board (PCB) 810 and may be used by the PCB 810 and other components coupled to the PCB. In a particular embodiment, the sensing elements are micro-fused silicon strain gauges (MSG). In order to measure the amount of force applied to the force-compliant element 802, the sensing elements 804 may be evenly distributed on a circle on a top surface of the force-compliant element 802.

[0071] The PCB 810 includes electrical components (integrated circuits, and passive elements such as resistors, capacitors, etc.) that are positioned and configured to receive the signals from the sensing elements.

[0072] In the force sensor apparatus 800, a support structure 808 has a surface on which the PCB 810 is coupled. The support structure may be made of many types of material, such as metal and plastic, that are suitable for supporting the PCB 810. In this example, the support structure 808 is positioned in a stack of the components of the force sensor apparatus 800 to rest on the force-compliant element 802. For example, in the assembled state, an outer rim of the support structure 808 is coupled to an outer rim 892 of the force-compliant element 802. The support structure 808 may also include openings (not pictured) through which the components of the PCB 810 may be coupled to the sensing elements 804.

[0073] In addition, the apparatus 800 also includes a sensor housing assembly 861 having a sensor housing 870 that covers the PCB 810 and the support structure 808. The sensor housing 870 is designed to protect the electrical components of the force sensor apparatus 800 and receive the counterforce for force measurement. In the assembled state, an outer rim of the sensor housing 870 is coupled to an outer rim 890 of the force-compliant element 802. [0074] The sensor housing assembly 861 also include a sensor cap portion 880 for housing electrical connections 888. The electrical connections 888 are coupled to and receive electrical signals from the electrical components of the PCB. The electrical connections 888 are configured for coupling with an external component and transmitting signals from the PCB to the external component.

[0075] The force-compliant element 802 has a bottom portion 849 with an outer rim 847 that surrounds the force interface 805. The outer rim 847 and the force interface 805 extend outward from the bottom portion 849 and are separated by a gap 845. In an alternative embodiment of force-compliant element with a spherical force interface, the outer rim of the force-complaint element and the force interface extend outward from the bottom portion and are not separated by a gap. In this alternative embodiment, the force interface is connected to and extends from the outer rim of the force-compliant element.

[0076] The force interface 805 forms a solid, spherical shape centered at a center line (not pictured) of the force-compliant element 802. The force interface 805 is configured to receive a load force and distribute the load force to the force-compliant element 802. The force-compliant element 802 also includes a support surface 854 for coupling to an interface structure and receiving a counter force. For example, the force interface 805 may be coupled to a component of an automobile electro-mechanical caliper brake system (e-caliper), such that the force applied to the component may be measured and reported by the apparatus 800. Readers of skill in the art will realize that the force interface may be optimized for particular applications by fine tuning the radius of the spherical shape.

[0077] For further explanation, FIG. 9A sets forth a diagram illustrating an example e-drum force sensor apparatus 900 with a spherical force interface 905. FIG. 9B illustrates another view of the e-drum force sensor apparatus of FIG. 9A and FIG. 9C sets forth a cross-section view of the e-drum force sensor apparatus of FIG. 9A. An automobile electro-mechanical drum brake system (e-drum) force sensor provides monitoring and control an electromechanical drum brake system.

[0078] The apparatus 900 includes a force-compliant element 902 arranged to receive oppositely directed forces. In a particular embodiment, the force-compliant element 902 is a component of material, such as metal or plastic, that deforms in response to applications of forces.

[0079] The apparatus 900 also includes sensing elements (not shown) coupled to the force- compliant element 902. Each of the sensing elements is configured to generate a signal indicating the degree that the force-compliant element 902 deforms in response to the application of oppositely directed forces. These signals from the sensing elements may be transmitted through electrical connections (not shown) to a printed circuit board (PCB) 910 and may be used by the PCB 910 and other components coupled to the PCB. In a particular embodiment, the sensing elements are micro-fused silicon strain gauges (MSG). In order to measure the amount of force applied to the force-compliant element 902, the sensing elements may be evenly distributed on a circle on a top surface of the force-compliant element 902. [0080] The PCB 910 includes electrical components (integrated circuits, and passive elements such as resistors, capacitors, etc.) that are positioned and configured to receive the signals from the sensing elements.

[0081] In the force sensor apparatus 900, a support structure 908 has a surface on which the PCB 910 is coupled. The support structure may be made of many ty pes of material, such as metal and plastic, that are suitable for supporting the PCB 910. In this example, the support structure 908 is positioned in a stack of the components of the force sensor apparatus 900 to rest on the force-compliant element 902. The support structure 908 may also include openings (not pictured) through which the components of the PCB 910 may be coupled to the sensing elements.

[0082] In addition, the apparatus 900 also includes a sensor housing 970 that covers the PCB 910 and the support structure 908. The sensor housing 970 is designed to protect the electrical components of the force sensor apparatus 900 and receive the counterforce for force measurement. In the assembled state, the sensor housing 970 is coupled to the force- compliant element 902, such that any force applied to the housing 970 is then applied or ■‘flows’⁷ through the housing and contacts the force-compliant element 902. For example, the housing 970 includes a support surface 954 for coupling to an interface structure and receiving a counter force.

[0083] The apparatus 900 also include a sensor cap 980 for housing electrical connections 988. The electrical connections 988 are coupled to and receive electrical signals from the electrical components of the PCB. The electrical connections 988 are configured for coupling with an external component and transmitting signals from the PCB to the external component.

[0084] The force-compliant element 902 has a bottom portion 949 with an outer rim 947 that surrounds the force interface 905. The outer rim 947 and the force interface 905 extend outward from the bottom portion 949 and are separated by a gap 945. The force interface 905 forms a solid, spherical shape centered at a center line (not pictured) of the force-compliant element 902. The force interface 905 is configured to receive a load force and distribute the load force to the force-compliant element 902. For example, the force interface 905 may be coupled to a component of an automobile electro-mechanical drum brake system (e-drum), such that the force applied to the component may be measured and reported by the apparatus 900. Readers of skill in the art will realize that the force interface may be optimized for particular applications by fine tuning the radius of the spherical shape. [0085] For further explanation, FIG. 10 sets forth a flowchart to illustrate an implementation of a method for assembling a force sensor apparatus according to embodiments of the present disclosure. The method of FIG. 10 includes attaching 1002 a printed circuit board (PCB) having electrical components to a support structure. Attaching 1002 a printed circuit board (PCB) having electrical components to a support structure may be carried out by soldering or applying an adhesive, tape, or glue to the bottom of a PCB (e.g., the PCB 710 of FIG. 7C; the PCB 810 of FIG. 8C; and the PCB 910 of FIG. 9C) to the support structure (e.g.. the support structure 708 of FIG. 7C; the support structure 808 of FIG. 8C; and the support structure 908 of FIG. 9C).

[0086] The method of FIG. 10 also includes electrically coupling 1004 the electrical components of the PCB to at least two sensing elements on a force-compliant element, the at least two sensing elements configured to measure forces applied to the force sensor apparatus. Electrically coupling 1004 the electrical components of the PCB to at least two sensing elements on a force ring may be carried out by connecting a lead from the PCB to the sensing elements on the force-compliant element (e.g., the force-compliant element (702) of FIG. 7C; the force-compliant element (802) of FIG. 8C; and the force-compliant element (902) of FIG. 9C).

[0087] The method of FIG. 10 also includes attaching 1006 the support structure to the force- compliant element that includes a force interface having a spherical shape that radiates outward from a center line of the force-compliant element. The force-compliant element has a bottom portion with an outer rim that surrounds a force interface. In this embodiment, the outer rim and the force interface extend outward from the bottom portion and are separated by a gap. The force interface forms a solid, spherical shape centered at a center line of the force-compliant element. The spherical force interface is configured to receive an application of load force and distribute the load force to the force-compliant element. The apparatus also includes one or more sensing elements coupled to the force-compliant element and configured to generate a signal indicating the degree that the force-compliant element deforms in response to the applications of forces to the force sensor apparatus. Attaching (1006) the support structure to the force-compliant element may be earned out by welding, gluing, or otherwise coupling the force-compliant element and the support structure.

[0088] For further explanation, FIG. 11 sets forth a flowchart to illustrate another implementation of a method for assembling a force sensor apparatus according to embodiments of the present disclosure. The method of FIG. 11 is similar to the method in FIG. 10 in that the method of FIG. 11 also includes all of the elements of FIG. 10. [0089] In addition, the method of FIG. 11 also includes positioning 1102 a sensor housing assembly over the electrical components of the PCB and the force-compliant element. Positioning 1 102 a sensor housing assembly over the electrical components of the PCB and the force-compliant element may be carried out by placing the sensor housing assembly (e.g., the sensor housing assembly 761 of FIG. 7C; the sensor housing assembly 861 of FIG. 8C) above the PCB.

[0090] Furthermore, the method of FIG. 1 1 also includes attaching 1104 the sensor housing assembly to the force-compliant element. Attaching 1104 the sensor housing assembly to the force-compliant element may be carried out by soldering or applying an adhesive, tape, or glue to the bottom to the sensor housing assembly for coupling the sensor housing assembly and the force-compliant element.

[0091] The flowchart and diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatus and methods according to various embodiments of the present disclosure. In some alternative implementations, the functions noted in the blocks or step in the method may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be performed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending on the functionality involved.

[0092] Advantages and features of the present disclosure can be further described by the following statements:

[0093] 1 . A force sensor apparatus, comprising: a force-compliant element that deforms in response to applications of forces to the force sensor apparatus, the force-compliant element having a bottom portion with an outer rim that surrounds a force interface, the outer rim and the force interface extending outward from the bottom portion, the force interface forming a solid, spherical shape centered at a center line of the force-compliant element, the spherical force interface configured to receive an application of load force and distribute the load force to the force-compliant element; and one or more sensing elements coupled to the force- compliant element and configured to generate a signal indicating the degree that the force- compliant element deforms in response to the applications of forces to the force sensor apparatus.

[0094] 2. The apparatus of statement 1 wherein the outer rim of the force-compliant element extends beyond the force interface in a direction perpendicular to a plane parallel to the bottom portion of the force-compliant element. [0095] 3. The apparatus of statement 1 or 2 wherein a center of the force interface is configured to contact with an external component to receive the application of the load force. [0096] 4. The apparatus of any of statements 1-3 further comprising: a printed circuit board configured to receive the signal from the one or more sensing elements; and a support structure having a surface on which the printed circuit board is coupled.

[0097] 5. The apparatus of any of statements 1-4 wherein the one or more sensing elements includes one or more gauges.

[0098] 6. The apparatus of any of statements 1-5 wherein the outer rim and the force interface are separated by a gap.

[0099] 6. The apparatus of any of statements 1-5 further comprising a sensor housing coupled to the force-compliant element and covering the PCB.

[00100] 7. The apparatus of any of statements 1-6 further comprising a sensor housing coupled to the force-compliant element and covering the PCB and the support structure. [00101] 8. The apparatus of any of statements 1-7 wherein the force sensor apparatus is an e- caliper force sensor apparatus.

[00102] 9. The apparatus of any of statements 1-7 wherein the force sensor apparatus is an e- pedal force sensor apparatus.

[00103] 10. The apparatus of any of statements 1-7 wherein the force sensor apparatus is an e-drum force sensor apparatus.

[00104] 11. A method of assembling a force sensor apparatus, the method comprising: attaching a printed circuit board (PCB) having electrical components to a support structure; electrically coupling the electrical components of the PCB to at least two sensing elements on a force-compliant element, the at least two sensing elements configured to measure forces applied to the force sensor apparatus; and attaching the support structure to a force-compliant element having a bottom portion with an outer rim that surrounds a force interface, the outer rim and the force interface extending outward from the bottom portion, the force interface forming a solid, spherical shape centered at a center line of the force-compliant element, the spherical force interface configured to receive an application of load force and distribute the load force to the force-compliant element.

[00105] 12. The method of statement 11 further comprising: positioning a sensor housing assembly over the electrical components of the PCB and the force-compliant element; and attaching the sensor housing assembly to the force-compliant element.

[00106] 13. The method of any of statements 11-12 wherein the one or more sensing elements includes one or more gauges. [00107] 14. The method of any of statements 11-13 wherein the outer rim of the force- compliant element extends beyond the force interface in a direction perpendicular to a plane parallel to the bottom portion of the force-compliant element.

[00108] 15. The method of any of statements 11-14 wherein a center of the force interface is configured to contact with an external component to receive the application of the load force. [00109] 16. The method of any of statements 11-15 wherein the outer rim and the force interface are separated by a gap.

[00110] 17. The method of any of statements 11-16 wherein the force sensor apparatus is an e-caliper force sensor apparatus.

[00111] 18. The method of any of statements 11-16 wherein the force sensor apparatus is an e-pedal force sensor apparatus.

[00112] 19. The method of any of statements 11-16 wherein the force sensor apparatus is an e-drum force sensor apparatus.

[00113] One or more embodiments may be described herein with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claims. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality.

[00114] To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claims. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

[00115] While particular combinations of various functions and features of the one or more embodiments are expressly described herein, other combinations of these features and functions are likewise possible. The present disclosure is not limited by the particular examples disclosed herein and expressly incorporates these other combinations.

Claims

CLAIMS What is claimed is:

1. A force sensor apparatus, comprising: a force-compliant element that deforms in response to applications of forces to the force sensor apparatus, the force-compliant element having a bottom portion with an outer rim that surrounds a force interface, the outer rim and the force interface extending outward from the bottom portion, the force interface forming a solid. spherical shape centered at a center line of the force-compliant element, the spherical force interface configured to receive an application of load force and distribute the load force to the force-compliant element; and one or more sensing elements coupled to the force-compliant element and configured to generate a signal indicating the degree that the force-compliant element deforms in response to the applications of forces to the force sensor apparatus.

2. The apparatus of claim 1 wherein the outer rim of the force-compliant element extends beyond the force interface in a direction perpendicular to a plane parallel to the bottom portion of the force-compliant element.

3. The apparatus of claim 1 wherein a center of the force interface is configured to contact with an external component to receive the application of the load force.

4. The apparatus of claim 1 further comprising: a printed circuit board configured to receive the signal from the one or more sensing elements; and a support structure having a surface on which the printed circuit board is coupled.

5. The apparatus of claim 1 wherein the one or more sensing elements includes one or more gauges.

6. The apparatus of claim 1 wherein the outer rim and the force interface are separated by a gap.

7. The apparatus of claim 4 further comprising a sensor housing assembly coupled to the force-compliant element and covering the PCB.

8. The apparatus of claim 1 wherein the force sensor apparatus is an e-caliper force sensor apparatus.

9. The apparatus of claim 1 wherein the force sensor apparatus is an e-pedal force sensor apparatus.

10. The apparatus of claim 1 wherein the force sensor apparatus is an e-drum force sensor apparatus. A method of assembling a force sensor apparatus, the method comprising: attaching a printed circuit board (PCB) having electrical components to a support structure; electrically coupling the electrical components of the PCB to at least two sensing elements on a force-compliant element, the at least two sensing elements configured to measure forces applied to the force sensor apparatus; and attaching the support structure to a force-compliant element having a bottom portion with an outer rim that surrounds a force interface, the outer rim and the force interface extending outward from the bottom portion, the force interface forming a solid, spherical shape centered at a center line of the force-compliant element, the spherical force interface configured to receive an application of load force and distribute the load force to the force-compliant element. The method of claim 11 further comprising: positioning a sensor housing assembly over the electrical components of the PCB and the force-compliant element; and attaching the sensor housing assembly to the force-compliant element. The method of claim 11 wherein the one or more sensing elements includes one or more gauges. The method of claim 11 wherein the outer rim of the force-compliant element extends beyond the force interface in a direction perpendicular to a plane parallel to the bottom portion of the force-compliant element. The method of claim 11 wherein a center of the force interface is configured to contact with an external component to receive the application of the load force. The method of claim 11 wherein the outer rim and the force interface are separated by a gap. The method of claim 11 wherein the force sensor apparatus is an e-caliper force sensor apparatus. The method of claim 11 wherein the force sensor apparatus is an e-pedal force sensor apparatus. The method of claim 1 1 wherein the force sensor apparatus is an e-drum force sensor apparatus.