Field of Invention

[0001] This disclosure relates generally to cables used in drive-by-wire applications for vehicles, and particularly to an Electrical Parking Brake (EPB) and Wheel Speed Sensor (WSS) cable with a single data wire.

Background of the Invention

[0002] In the automotive industry load/data cables, i.e., those having both a load line and data line are well known and have been used for a long period of time for reducing the weight of load and data wirings in vehicles and for simplifying their assembly.

[0003] The rapid transition to drive-by-wire technologies in general, and in particular to a brake-by-wire configuration, poses challenging technical and cost-related problems for the industry, which arise from the increasing amount of necessary wiring. The utilization of such load/data cables is a sustainable way for manufactures to keep costs at bay, but such a configuration adds certain problems related to electrical safety and reliability. For example, expansive electrical safety requirements necessitate the use of voluminous claddings and jackets in such cables, which contribute to the cables, and thus the vehicle’s weight. The reliability of data transfer is also critically important in vehicles because if interference between load and data lines in a load/data cable is not properly mitigated, such interference may distort or prevent data transfer, potentially causing life-threatening occurrences. Such requirements have made traditional load/data cables relatively heavy and expensive. [0004] Various solutions are known in the art, which constitute a combination of two load wires for delivering power to the EPB and two data wires for delivering data from the WSS to a Vehicle Control Unit (VCU). In order to achieve a desired level of insulation between the load and data wires, additional separation films made of nonwovens or paper layers are conventionally used: and for the attenuation of interference between the EPB and WSS lines metal braids and foils (e.g., metal shielding) are usually employed. Such a complex multi-layer structure of such a contemporary load/data design results in high manufacturing costs, while also resulting in a heavy weight cable, which is undesirable.

Summary of the Invention

[0005] Various illustrative embodiments of the present disclosure provide a complex cable and related methods. In accordance with one aspect of an illustrative embodiment of the present disclosure, the complex cable is implemented with a WSS, EPB, and associated control module.

[0006] The present disclosure allows for reducing the weight of load/data cables for the

EPB and WSS; decreasing the amount of materials needed for their manufacturing and simplifying the manufacturing process, thereby reducing the cost of the final product.

[0007] According to configurations of an automobile, a WSS produces low frequency signals, typically not exceeding several kHz. The WSS is connected to the vehicle’s EPB and WSS control module, which feeds DC voltage to the WSS. When a vehicle is in motion, a WSS sensor monitors the wheel’s angular velocity and provides an electric sine or rectangular (depending on which kind of sensor is used) impulse to a control module. A conventional variable (passive) wheel speed sensor is comprised of a magnetic pin, with a wrapped wire. When a toothed metal ring, which is firmly connected with a wheel, approaches the pin's end a magnetic flux changes, causing a voltage variations at the wire’s terminals. The frequency of the signal produced is directly proportional to the wheel’s rotational speed, and when it increases, the signal’s amplitude similarly increases. An amplitude of the electromotive force is the time derivation of a solenoid’s reluctance, a passive wheel speed sensor generates a low-voltage signal at low speed. Accordingly, the controller, which cannot read this poorly discernible signal, does not do so at all at speeds, particularly at speeds, for example, of 3 - 5 mph.

[0008] According to configurations of an automobile, the EPB is an electromagnetic system that fixes a vehicle in a motionless state by using a DC motor, which applies pressure to braking pads via the EPB’s gear train and spindle piston. Since an EPB is commonly used only when a vehicle is motionless or when its speed is below 5 mph, the EPB is active when a vehicle is motionless and the WSS operates only when it is in motion.

[0009] One aspect of the present disclosure relates to the separation of signals in time in consideration of the fact that the WSS generates a low-frequency signal not exceeding several kHz and that the EPB is active only when a vehicle is motionless and the WSS operates only when the vehicle is in motion. According to this aspect, a WSS data return wire is omited, and instead, one of two EBP load wires, in particular an EBP ground wire, is utilized as a return conductor for the W SS. The low-frequency data signals generated by the sensor of the WSS allows for producing cables with length of up to 15m, in which there are no wave conditions, so that an adaptation of the impedance between the data wire and the load wires can be omitted.

[0010] According to aspects of the present disclosure, a cable for connecting a WSS,

EPB, and control module comprises an EPB ground load wire, an EPB power load wire, and a WSS power data wire. Each of the EPB ground load wire, EPB power load wire, and WSS power data wire may include a central conductive core surrounding by insulation. The EPB ground load wire, EPB power load wire, and WSS power data wire may be collectively encased in a common outer sheath.

[0011] According to embodiments, the EPB ground load wire and EPB power load wire have approximately the same outer diameter. The centers of the EPB ground load wire and EPB power load wire (i.e., the centers in a cross-sectional view along the length of the cable) may lie in a common plane that cuts through the center of the cable in a cross-sectional view. According to these embodiments, the EPB ground load wire and EPB power load wire may run parallel to each other along the length of the cable. According to certain embodiments, the EPB ground load wire and EPB power load wire contact each other at, at least one point on their respective outer surfaces.

[0012] According to embodiments, the WSS power data wire has an outer diameter that is less than the outer diameter of the EPB ground load wire and EPB power load wire. According to these embodiments, the WSS power data wire may have a center (i.e., the centers in a cross- sectional view along the length of the cable) located between the centers of the EPB ground load wire and EPB power load wire. According to one embodiment, the WSS power data wire may be located in a recessed space formed by the EPB ground load wire and EPB power load wire.

[0013] According to aspects implementing the cable, a control module, winch controls the WSS and EPB, is connected to the WSS and EPB at least partially by way of the cable. According to embodiments, the EPB ground load wire, the EPB power load wire, and the WSS power data wire at a first end of the cable are terminated and connected to the control module. The EPB ground load wire, the EPB power load wire, and the WSS power data wire at a second end of the cable are similarly terminated. At the second end of the cable the EPB ground load wire and the EPB power load wire terminations are connected to the EPB, while the WSS power data wire termination is connected to the WSS. The EPB ground terminal and the WSS ground terminal are electrically connected with each other by means of a conductive bridge. According to embodiments, the conductive bridge may take the form of an insulated wire or an uninsulated wire. According to alternative embodiments, the conductive bridge may take the form of a part of an external housing, which houses the EPB and W SS. For example, the conductive bridge may be a metallic (or other conductive part) portion of a housing that houses the EPB and WSS. According to still further embodiments, the conductive bridge may be built into an electronic device (e.g., a circuit board) that includes additional functional elements (e.g., inductors, capacitors, etc.).

Brief Description of the Drawings

[0014] The following description is given as an example, and is not intended to limit the scope of the invention to the disclosed details, is made in conjunction with the accompanying drawings, wherein:

[0015] FIG.1 shows a transverse-sectional view of a WSS and EPB cable of the present disclosure;

[0016] FIG.2 shows a WSS and EPB cable of the present disclosure connected to respective elements. Detailed Description

[0017] Detailed embodiments of the present connection systerm and methods are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of a connection system, and methods that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the connection systems and methods are intended to be illustrative, and not restrictive. Further, the drawings and photographs are not necessarily to scale, and some features may be exaggerated to show details of particular components. In addition, any measurements, specifications and the like shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present cable system, and methods.

[0018] When a vehicle moves, the WSS constantly tracks wheel speed. The frequency of signals passing through the WSS line do not typically exceed several kHz, and there are no wave conditions in WSS cables having a length of up to 15m. Therefore, an adaptation of the impedance between the data wire and the power wires is omitted. When a vehicle is at standstill the EPB operates and the WSS does not. With this in mind, and according to embodiments, only one dedicated wire is necessary for the WSS to properly function.

[0019] With reference to FIG.1, a transverse-sectional view of an embodiment of a complex cable 8 of the present disclosure is illustrated. The cable 8 comprises three wires: one EPB ground load wire 1 or 2; one EPB power load wire 1 or 2, and one WSS power data wire 3. Each of the three wires may each include a conductive core that is insulated, while all three are covered with a common sheath 4. According to embodiments, EPB wires 1, 2 touch each other along the length of cable 8, so as touch points form a line parallel to the cable’s longitudinal centra! line of symmetry.

[0020] According to embodiments, the EPB ground load wire 1 or 2 and EPB power load wire 1 or 2 have approximately the same outer diameter. The centers of the EPB ground load wire 1 or 2 and EPB power load wire 1 or 2 (i.e., the centers in a cross-sectional view along the length of the cable) may lie in a common plane that cuts through the center of the cable 8 in a cross-sectional view. According to certain of these embodiments, the EPB ground load ware and EPB power load wire may run parallel to each other along the length of the cable 8. According to further embodiments, EPB ground load wire 1 or 2 and EPB power load wire 1 or 2 may be a twisted wire pair. According to these embodiments, WSS power data wire 3 may similarly be twisted so as to keep a fixed wire orientation (e.g., the configuration of Fig. 1).

[0021] According to embodiments, the WSS power data wire 3 has an outer diameter that is less than the outer diameter of the EPB ground load wire and EPB power load wire 1, 2.

According to these embodiments, the WSS power data wire may have a center (i.e., the center in a cross-sectional view along the length of the cable) located between the centers of the EPB ground load wire and EPB power load wire. That is, the center of WSS power data wire 3, as illustrated in FIG. 1, is located in a vertical plane that is between the centers of the EPB ground load wire and EPB power load wire 1, 2. According to one embodiment, the WSS power data wire 3 may be located in a recessed space formed by the EPB ground load wire and EPB power load wire. According to these embodiments, power data wire 3 may be adjacent to and abut each of the EPB ground load wire 1 or 2 and EPB power load wire 1 or 2. [0022] A filler material may be located in the spaces between the wires and the outer sheath such that the wires do not move within the cable. According to certain embodiments, during manufacture the outer sheath may be formed via an extrusion process (e.g., pressure extrusion), such that its thickness fills the interior space of cable 8 and makes contact with the outer surface of the wires. Accord to alternative embodiments, the spaces between the wires and the outer sheath may be filled with a filler material (e.g., yam, filaments, etc.). Additionally, the space between the wires (i.e., the space created by abutting surfaces of the wires) may also be filled with such a filler material (or left empty). According to alternative embodiments, the space between the wires and the outer sheath is left empty (e.g., filled with a gas), such that the wires may move within the cable.

[0023] According to embodiments where the outer sheath may be formed via an extrusion process, and in particular a pressure extrusion process, a separator (not shown) may surround the wires, thus separating them from contacting the outer sheath. According to embodiments, the separator may take the form of a foil, paper, or fleece sheath, and thus act as an inner sheath for encasing the three wires. According to alternative embodiments the separator may take the form of a powder that is placed (e.g., sprayed) on the three wires.

[0024] With the above description in mind, the cable may consist essentially of two load wires, one data wire, and an outer sheath. According to a preferred embodiment, the cable consists of two load wires, one data wire, and an outer sheath.

[0025] With reference to FIG.2, an embodiment of cable 8 connected to respective modules of the present disclosure is illustrated. A ground terminal of the WSS 5 is connected with a ground terminal of the EPB 6 by means of a conductive bridge 9. The EPB 6 and WSS 5 are connected with the EPB and WSS Control Module 7, which controls by the WSS 5 and EPB 6, by the way of cable 8. For example, the EPB ground load wire, the EPB power load wire, and the WSS power data wire at a first end of the cable are terminated and connected to respective terminals of the control module 7. The EPB ground load wire, the EPB power load wire, and the WSS power data wire at a second end of the cable 8 are similarly terminated. At the second end of the cable 8 the EPB ground load wire and the EPB power load wire terminations are connected to the EPB, while the WSS power data wire termination is connected to the WSS.

[0026] The EPB 6 is active only when a vehicle is motionless and the WSS 5 operates only when the vehicle is in motion, the shared EPB ground load wire 1 or 2 is used for both the WSS and EBP individually. Neither the WSS nor EPB are active at the same time, and thus, the shared EPB ground wire does not cater to both the WSS and EBP concurrently. When a vehicle is in motion, the WSS continuously monitors the rotational speed of its wheel, and the EPB is not active, so that the EPB does not require a supply of power. In this scenario, the signals generated by the WSS are delivered to the EPB and WSS Control Module through the EPB’s ground wire, by way of the conductive bridge and the W SS power data wire. When the vehicle decelerates and come to a standstill, the data on the vehicle wheels’ angular speed are no longer needed, but securing the vehicle’s motionless position by means of the EBP is necessary. In this mode, when the WSS is non-active, the EPB and WSS Control Module 7 delivers DC voltage to the EPB’s DC motor through the EBP power and ground wires, which, in turn, by using an EPB gear train and spindle piston, activates the wheel’ s braking pads.

[0027] According to embodiments, the conductive bridge 9 may take the form of an insulated ware or an uninsulated wire. According to alternative embodiments, the conductive bridge 9 may take the form of a part of an external housing, which houses the EPB and WSS. For example, the conductive bridge 9 may be a metallic (or other conductive part) portion of a housing that houses the EPB and WSS. According to a specific example, the conductive bridge may be a metallic portion of the under carriage of the automobile to which the EPB and WSS are mounted. According to still further embodiments, the conductive bridge 9 may be built into an electronic device (e.g., a circuit board) that includes additional functional elements (e.g., inductors, capacitors, etc.).

[0028] The three-wire cable system of the present disclosure provides the advantages of reducing the costs associated with mass production of EBP and WSS cables as well as reducing the weight of cabling necessary to run the W'SS and EPB, which reduces the weight of the final product (e.g., vehicle). These advantages are realized at least in part based upon the use of three wires, as compared to four wires, which are routinely used in the industry. This means that the cable’s final weight (e.g., the weight per unit of length) is reduced by at least by the weight of a single wire as compared to contemporary load/data cables; and its specific manufacturing cost are similarly reduced. The cost reduction may be even greater because of additional reduction of associated assembly costs.