Detector

Abstract

To provide a detector capable of properly detecting inundation.SOLUTION: A detector 1 includes a sensor unit 10, CAN transceiver 36, and control unit 35. The sensor unit 10 includes a resistor 15 connected to a first conducting part 11 and second conducting part 12 included in a sensor substrate 18, and is installed in an area having a possibility of inundation. The CAN transceiver 36 outputs an inundation detection signal to the first conducting part 11, and receives an inundation detection signal from the second conducting part 12 via the resistor 15. The control unit 35 includes an inundation detection block 352 that detects inundation of the sensor unit 10 on the basis of the inundation detection signal. The CAN transceiver 36 and control unit 35 are installed in a place different from that of the sensor unit 10. When a received inundation detection signal has a signal pattern different from a normal-time signal pattern, the inundation detection block 352 determines that the sensor unit 10 is inundated.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a detection device. [Background technology]

[0002] Conventionally, there is known an electric power steering device in which an assist mechanism is provided on a rack shaft. For example, in Patent Document 1, a water detection device is provided that detects water accumulated in a recess of a housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-234102 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a pair of electrodes is used as a water detection device, and water is detected by the electrical continuity caused by the immersion of the pair of electrodes through water. However, in Patent Document 1, it is necessary to add logic for detecting water intrusion, such as applying a voltage to the electrodes from the control unit and detecting the voltage.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a detection device capable of appropriately detecting water ingress. [Means for solving the problem]

[0006] The detection device of the present invention includes a sensor unit (10, 100), a communication circuit (36), and a control unit (35). The sensor unit has a resistor (15) or a capacitor (16) connected to a first conductive unit (11) and a second conductive unit (12) provided on a sensor board (18), and is provided in an area where water may be present. The communication circuit (36) outputs a water ingress detection signal to the first conductive unit, and receives the water ingress detection signal from the second conductive unit via the resistor or the capacitor. The control unit has a water ingress detection unit (352) that detects water ingress in the sensor unit based on the water ingress detection signal.

[0007] The communication circuit and the control unit are provided in a location different from the sensor unit. If the received water-submersion detection signal has a signal pattern different from that of a normal state, the water submersion detection unit determines that the sensor unit is submerged in water. This allows water submersion to be detected appropriately. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing a steering system according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing an electric power steering device according to a first embodiment. [Diagram 3] FIG. 1 is a schematic diagram showing a detection device according to a first embodiment. [Figure 4] FIG. 1 is a block diagram showing a detection device according to a first embodiment. [Diagram 5] 4 is a time chart illustrating water submersion detection according to the first embodiment. [Figure 6] 4 is a flowchart illustrating a water submersion detection process according to the first embodiment. [Figure 7] FIG. 4 is a schematic diagram showing a detection device according to a second embodiment. [Figure 8] FIG. 11 is a block diagram showing a detection device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) A detection device according to the present invention will be described below with reference to the drawings. In the following, in a number of embodiments, substantially the same configurations are given the same reference numerals and description thereof will be omitted. A detection device according to a first embodiment is shown in Figs. 1 to 6. As shown in Figs. 3 and 4, the detection device 1 includes a sensor unit 10, a CAN transceiver 36, and a control unit 35, and is applied to an electric power steering device 8 which is a steering device for assisting the steering operation of a vehicle (see Fig. 2).

[0010] 1 shows the overall configuration of a steering system 90 including an electric power steering device 8. The steering system 90 includes a steering wheel 91, which is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, the electric power steering device 8, and the like.

[0011] The steering wheel 91 is connected to a steering shaft 92. A torque sensor 93 that detects steering torque is provided on the steering shaft 92. A pinion gear 96 is provided at the end of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like. Various parts related to the transmission of steering and provided on the path from the steering wheel 91 to the wheels 98 are referred to as steering transmission parts. The steering transmission parts include the steering shaft 92, the pinion gear 96, the rack shaft 97, etc.

[0012] When a driver turns a steering wheel 91, a steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of a rack shaft 97 by a pinion gear 96. A pair of wheels 98 are steered to an angle according to the amount of displacement of the rack shaft 97.

[0013] The electric power steering device 8 includes a drive device 30 having an ECU 31 and a motor 60, and a speed reduction mechanism 70 as a power transmission section that reduces the speed of rotation of the motor 60 and transmits it to a rack shaft 97. The electric power steering device 8 of this embodiment is a so-called "rack assist type", but may be a so-called "column assist type" in which the rotation of the motor 60 is transmitted to a steering shaft 92. The drive device 30 is attached to the vertically lower side of the rack shaft 97.

[0014] The ECU 31 is provided with connectors 41 and 42. The connector 41 is provided so as to be connectable to the vehicle communication network 6, the sensor unit 10, and a vehicle power source (not shown). In this embodiment, the vehicle communication network 6 and the sensor unit 10 are connected by CAN (Controller Area Network) wiring 43 and 44, which are signal wiring. The connector 42 is connected to a torque sensor 93. In this embodiment, the connector 41 is an integrated hybrid connector in which a communication system connector and a power system connector are integrated, but the openings may be separated for the communication system and the power system. The number and orientation of the openings of the connector can be designed as appropriate.

[0015] The motor 60 is a three-phase brushless motor. The motor 60 outputs a part or all of the torque required for steering, and is driven by power supplied from a vehicle power source to rotate the reduction gear mechanism 70 forward and reverse. The reduction gear mechanism 70 is housed in a gear housing 75.

[0016] As shown in FIG. 2, the drive device 30 has the ECU 31 integrally provided on one side of the motor 60 in the axial direction, and is a so-called “mechanically and electrically integrated” type. However, the motor 60 and the ECU 31 may be provided separately without being of the mechanically integrated type.

[0017] The ECU 31 has an ECU board 32, connectors 41 and 42, and an ECU cover 45. On the ECU board 32, various electronic components are mounted, such as a microcomputer constituting a control unit 35, a CAN transceiver 36 (see FIG. 3), a switching element 37 that switches the current supply to the motor line 66, and a rotation angle sensor 38.

[0018] The connectors 41, 42 are connected to the ECU board 32 by connector terminals. The openings of the connectors 41, 42 are provided on the outside of the ECU cover 45 and are provided so that the harness can be inserted and removed. The ECU cover 45 is formed in a generally cylindrical shape with a bottom and houses the ECU board 32 therein. The connectors 41, 42 and the ECU cover 45 may be formed integrally.

[0019] The motor 60 includes a motor case 61, a motor frame 62, a stator 63, a rotor 64, a shaft 65, and a motor wire 66. The motor case 61 is formed in a cylindrical shape with a bottom that opens to the ECU 31 side, and the stator 63 is fixed to the radially inner side. The motor frame 62 is provided on the opening side of the motor case 61.

[0020] The rotor 64 is provided radially inside the stator 63 and is provided so as to be rotatable relative to the stator 63. The shaft 65 is fitted into the rotor 64 and rotates integrally with the rotor 64. The shaft 65 is rotatably supported by the motor case 61 and the motor frame 62 by bearings 651 and 652. A waterproof rubber 653 is provided on the small diameter pulley 71 side of the bearing 651 to separate the interior of the gear housing 75 from the interior of the motor 60. An end of the shaft 65 on the ECU 31 side is exposed from the motor frame 62 to the ECU board 32 side, and a sensor magnet 655 is provided thereon. A rotation angle sensor 38 is provided at a location facing the sensor magnet 655.

[0021] The motor wire 66 is wound around the stator 63. Lead wires 661 are taken out from each phase of the motor wire 66 and connected to the ECU board 32. A rotating magnetic field is formed in the stator 63 by controlling the supply of electricity to the motor wire 66. A magnet is provided on the radially outer side of the rotor 64, and the rotor 64 rotates integrally with the shaft 65 due to the rotating magnetic field formed in the stator 63.

[0022] The reduction gear mechanism 70 has a small diameter pulley 71, a large diameter pulley 72, and a belt 73. The small diameter pulley 71 is provided at the end of the shaft 65 opposite the ECU 31, and rotates integrally with the shaft 65. The large diameter pulley 72 is formed to have a larger diameter than the small diameter pulley 71. The diameters of the pulleys 71 and 72 are appropriately set according to the required reduction ratio. The belt 73 is wound around the small diameter pulley 71 and the large diameter pulley 72.

[0023] When the motor 60 rotates, the motor torque is transmitted to the large diameter pulley 72 via the small diameter pulley 71 and the belt 73. The rotation of the large diameter pulley 72 is converted into linear motion of the rack shaft 97 by the rack and pinion mechanism.

[0024] The small diameter pulley 71 is accommodated in a gear housing 75. The large diameter pulley 72 and the rack shaft 97 are accommodated in a cylindrical rack housing 76. In FIG. 2, the gear housing 75 and the rack housing 76 are integrally formed, but they may be formed separately. Inside the gear housing 75, a sensor unit 10 is provided on the vertically lower side. A CAN wiring 44 connected to the sensor unit 10 is taken out from a hole formed in the gear housing 75 and connected to the connector 41.

[0025] 3 and 4, the sensor unit 10 has a first conductive portion 11, a second conductive portion 12, and a resistor 15. The first conductive portion 11, the second conductive portion 12, and the resistor 15 are provided on a sensor board 18. The sensor board 18 is attached to the inside of the gear housing 75, on the lower wall in the vertical direction.

[0026] The first conductive part 11 is connected to a first terminal 311 of the ECU 31. The second conductive part 12 is connected to a second terminal 312 of the ECU 31. One end of the resistor 15 is connected to the first conductive part 11, and the other end is connected to the second conductive part 12. The resistance value of the resistor 15 is appropriately set to a value that enables CAN communication. As a result, the CAN signal transmitted from the first terminal 311 is input to the second terminal 312 via the first conductive part 11, the resistor 15, and the second conductive part 12.

[0027] The ECU 31 has a control unit 35, a CAN transceiver 36, etc. The control unit 35 is mainly composed of a microcomputer, etc., and includes a CPU, ROM, RAM, I / O, and bus lines connecting these components, none of which are shown. Each process in the control unit 35 may be software processing in which the CPU executes a program stored in advance in a substantial memory device (i.e., a readable non-transitory tangible storage medium) such as a ROM, or may be hardware processing in which a dedicated electronic circuit is used.

[0028] 4, the control unit 35 has, as functional blocks, a drive control unit 351, a water intrusion detection unit 352, and a notification unit 353. The drive control unit 351 performs various processes relating to drive control of the motor 60.

[0029] The flooding detection unit 352 uses the CAN signal as a flooding detection signal to detect flooding of the sensor unit 10. When flooding is detected, the notification unit 353 notifies the driver that flooding has occurred, for example by turning on a warning light 48 provided on the instrument panel. Alternatively, the notification may be by voice through a speaker 49.

[0030] The CAN transceiver 36 converts the bit signal from the control unit 35 into a CAN_H signal and a CAN_L signal, and outputs them to the sensor unit 10 side via the first terminal 311. The CAN signal output from the CAN transceiver 36 to the sensor unit 10 passes through the first conductive unit 11, the resistor 15, and the second conductive unit 12, and is input to the second terminal 312. The CAN transceiver 36 converts the CAN signal input from the sensor unit 10 side via the second terminal 312 into a bit signal, and outputs it to the control unit 35. Note that in FIG. 4, some control lines, signal lines, etc. are omitted to avoid complication.

[0031] Details of water submersion detection will be described with reference to the time chart in Fig. 5. In Fig. 5, a common time axis is taken as the horizontal axis, and from the top, an output signal from control unit 35, an input signal to control unit 35, and a CAN signal, which are a CAN_H signal and a CAN_L signal, are shown.

[0032] A square wave signal with a predetermined period is output from the control unit 35. When the sensor unit 10 is not submerged in water, the CAN_H signal and the CAN_L signal transmitted and received from the CAN transceiver 36 are square wave signals corresponding to the output signal. Also, the input signal input from the CAN transceiver 36 is a square wave signal corresponding to the output signal. When the input signal is a normal pattern corresponding to the output signal, the water submersion detection unit 352 determines that the sensor unit 10 is not submerged in water.

[0033] When the sensor unit 10 is submerged in water at time xf, the first conductive part 11 and the second conductive part 12 are shorted, and the CAN signal cannot be transmitted or received, so that the CAN_H signal and the CAN_L signal have an abnormal pattern different from the normal pattern. In FIG. 5, an example is shown in which the CAN_H signal and the CAN_L signal are fixed at a predetermined value (e.g., 2.5 [V]), but depending on the condition of the water, the abnormal pattern may be other than the predetermined value fixation. In addition, the input signal input from the CAN transceiver 36 has an abnormal pattern different from the output signal. When the input signal has an abnormal pattern different from the output signal, the water submersion detection unit 352 determines that the sensor unit 10 is submerged in water.

[0034] The water submersion detection process of this embodiment will be described with reference to the flowchart of Fig. 6. This process is executed at a predetermined cycle by the control unit 35. Hereinafter, the "step" of step S101 will be omitted and the step will be abbreviated to the symbol "S".

[0035] The control unit 35 outputs a water submersion detection signal in S101, and receives the water submersion detection signal in S102. In S103, the control unit 35 judges whether the received signal is normal or not. If it is judged that the received signal is normal (S103: YES), the process proceeds to S104, and it is determined that the sensor unit 10 is not submerged in water. If it is judged that the received signal is not normal (S103: NO), the process proceeds to S105, and it is determined that the sensor unit 10 is submerged in water. In S106, the notification unit 353 notifies the driver that water submersion has occurred.

[0036] In FIG. 6, for the sake of simplicity, the signal transmission and reception and water submersion detection are depicted as a series of processes. However, for example, if the signal transmission and reception are performed at a relatively high speed, the signal transmission and reception cycle and the anomaly detection cycle may be different.

[0037] In the electric power steering device 8, there is a risk of water entering the inside of the gear housing 75, as indicated by the arrow W in Fig. 2. If the entered water freezes, there is a risk that torque transmission from the motor 60 will be impeded. Therefore, in this embodiment, a sensor unit 10 is provided inside the gear housing 75, and water ingress is detected by transmitting and receiving CAN signals. By utilizing CAN communication, which is commonly used in vehicles, water ingress can be detected with a relatively simple configuration without adding any special logic for water ingress detection.

[0038] As described above, the detection device 1 includes the sensor unit 10, the CAN transceiver 36, and the control unit 35. The sensor unit 10 has the resistor 15 connected to the first conductive unit 11 and the second conductive unit 12 provided on the sensor substrate 18, and is provided in an area that may be subject to flooding.

[0039] The CAN transceiver 36 outputs a water submersion detection signal to the first conductive section 11, and receives the water submersion detection signal from the second conductive section 12 via the resistor 15. The control section 35 has a water submersion detection section 352 that detects water submersion in the sensor section 10 based on the water submersion detection signal. The CAN transceiver 36 and the control section 35 are provided in a location different from the sensor section 10. In this embodiment, they are provided in the ECU 31, which is a control unit. The water submersion detection section 352 determines that the sensor section 10 is submerged in water when the received water submersion detection signal has a signal pattern different from that in a normal state. This makes it possible to detect water submersion with a relatively simple configuration.

[0040] The detection device 1 is used in a steering system 90 related to steering of a vehicle. The sensor unit 10 is provided inside a gear housing 75 that houses a reduction mechanism 70 that connects a steering transmission path from a steering wheel 91 to wheels 98 to a motor 60. The control unit 35 has a drive control unit 351 that controls the drive of the motor 60. This makes it possible to appropriately detect water ingress in the gear housing 75. In particular, when the reduction mechanism 70 is attached to a rack shaft 97 close to the ground, the detection device 1 is preferably used because the reduction mechanism 70 is more likely to be submerged in water than when the reduction mechanism 70 is mounted at a position relatively far from the ground. In addition, since water ingress detection is performed by the control unit 35 used for drive control of the motor 60, no separate control component is required for water ingress detection.

[0041] In this embodiment, the water inundation detection signal is a CAN signal. When the water inundation detection signal reaches a constant value, the water inundation detection unit 352 determines that the sensor unit 10 is submerged in water. Note that the constant value is one in which fluctuations due to detection errors and noise are permitted. By using a CAN signal that is generally used in vehicles for water inundation detection, normal CAN communication control can be applied, and no separate logic for water inundation detection is required. Furthermore, by utilizing an existing CAN circuit, the impact on noise performance can be suppressed.

[0042] Second embodiment The second embodiment is shown in Fig. 7 and Fig. 8. As shown in Fig. 7 and Fig. 8, the detection device 2 includes a sensor unit 100, a CAN transceiver 36, and a control unit 35. The sensor unit 100 of this embodiment is similar to the sensor unit 10 of the above embodiment, except that a capacitor 16 is provided instead of the resistor 15. The capacitor 16 is, for example, a surface-mount type ceramic capacitor having a capacitance that allows CAN communication. One electrode of the capacitor 16 is connected to the first conductive part 11, and the other electrode is connected to the second conductive part 12.

[0043] Similarly to the above embodiment, when the capacitor 16 is provided instead of the resistor 15, if the sensor unit 100 is submerged in water, the first conductive unit 11 and the second conductive unit 12 are shorted, making it impossible to send and receive CAN signals, and the CAN_H signal and the CAN_L signal exhibit an abnormal pattern different from normal, making it possible to detect submersion of the sensor unit 100 in water. Details of submersion detection are the same as those of the above embodiment.

[0044] In this embodiment, the detection device 2 includes a sensor unit 100, a CAN transceiver 36, and a control unit 35. The sensor unit 100 has a capacitor 16 connected to a first conductive unit 11 and a second conductive unit 12 provided on a sensor substrate 18, and is provided in an area that may be subject to flooding.

[0045] The CAN transceiver 36 outputs a water submersion detection signal to the first conductive section 11, and receives the water submersion detection signal from the second conductive section 12 via the capacitor 16. The control section 35 has a water submersion detection section 352 that detects water submersion in the sensor section 100 based on the water submersion detection signal. The CAN transceiver 36 and the control section 35 are provided in a location different from the sensor section 100, and the water submersion detection section 352 determines that the sensor section 100 is submerged in water if the received water submersion detection signal has a signal pattern different from that in a normal state. This configuration also provides the same effects as the above embodiment.

[0046] In the embodiment, the CAN transceiver 36 corresponds to the "communication circuit", the reduction gear mechanism 70 corresponds to the "power transmission section", the gear housing 75 corresponds to the "housing", and the steering wheel 91 corresponds to the "steering member".

[0047] (Other embodiments) In the above embodiment, a CAN signal is used as the water ingress detection signal. In other embodiments, a signal other than a CAN signal may be used as long as the signal changes when the sensor unit is inundated with water. When a signal other than a CAN signal is used as the water ingress detection signal, a communication circuit that corresponds to the communication method can be used instead of a CAN transceiver.

[0048] In the above embodiment, the sensor board is provided on the bottom surface of the gear housing. In other embodiments, the sensor board may be provided anywhere where water ingress is possible and where it is desired to detect water ingress, for example, the sensor board may be attached to a vertically lower side surface of the gear housing. In other embodiments, a circuit component other than a resistor or a capacitor, such as an inductor, may be mounted on the sensor board. Also, a circuit pattern other than the first conductive portion and the second conductive portion may be formed on the sensor board.

[0049] In the above embodiment, the detection device is applied to a steering system including an electric power steering device. In other embodiments, the steering system may be a steer-by-wire system or the like. In other embodiments, the detection device may be applied to a device or system other than a steering system. In addition, the configuration of the drive device and the power transmission unit may be different from those in the above embodiment.

[0050] The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. As described above, the present invention is not limited to the above embodiment, and can be implemented in various forms within the scope of the invention. [Explanation of symbols]

[0051] 1, 2: Detection device 10, 100: Sensor unit 11... First conductive part 12... Second conductive part 15 Resistor 16 Capacitor 18 Sensor board 31...ECU 35...Control unit 351 Drive control unit 352 Water ingress detection unit 36 CAN transceiver (communication circuit) 60 Motor 70 Reduction gear (power transmission part) 75 Gear housing (housing) 90···Steering system 91 ... steering wheel (steering member) 98 ... wheel

Claims

1. a sensor unit (10, 100) provided in an area where flooding may occur, the sensor unit having a resistor (15) or a capacitor (16) connected to a first conductive portion (11) and a second conductive portion (12) provided on a sensor substrate (18); a communication circuit (36) that outputs a water submersion detection signal to the first conductive portion and receives the water submersion detection signal from the second conductive portion via the resistor or the capacitor; a control unit (35) having a water ingress detection unit (352) that detects water ingress of the sensor unit based on the water ingress detection signal; Equipped with the communication circuit and the control unit are provided at locations different from the sensor unit, The water submersion detection unit is a detection device that determines that the sensor unit is submerged in water when the received water submersion detection signal has a signal pattern different from that during normal operation.

2. A steering system (90) for steering a vehicle, the sensor unit is provided inside a housing (75) that accommodates a power transmission unit (70) that connects a steering transmission component extending from the steering member (91) to the wheels (98) and a motor (60); The detection device according to claim 1 , wherein the control unit has a drive control unit (351) that controls driving of the motor.

3. The water submersion detection signal is a CAN signal, The detection device according to claim 1 , wherein the water-immersion detection unit determines that the sensor unit is submerged in water when the water-immersion detection signal reaches a constant value.

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