ULTRASCHALLSENSOR

Abstract

Ultrasonic sensor (1), comprising: an ultrasonic wave transmitter receiver (2) comprising a vibration element (21) with a function for converting between mechanical vibration and an electrical signal and a transmitter receiver box (22) configured to cover the vibration element (21); a sensor box (5) which accommodates a control board (60) which is electrically connected to the ultrasonic wave transmitter (2), and carries the ultrasonic wave transmitter (2); and a shielding element (7) which electromagnetically shields at least a part of an electrical circuit (6) including the vibration element (21) and the control board (60) in at least five of six directions and has a first end (71) and a second end (72), wherein the shielding element (7) is designed in a thin sheet metal or wire mesh form; the part of the electrical circuit (6) to be shielded includes at least the control board (60); the first end (71) of the shielding element (7) is configured to be permanently connected to a ground wire (G) in order to electromagnetically shield at least part of the electrical circuit (6); and the second end (72) is configured to be selectively connected to a power source (B), wherein the shielding element (7) is configured to generate heat when it is powered while the second end (72) is connected to the power source (B).

Description

[Technical field]

[0001] The present invention relates to an ultrasonic sensor. [State of the art]

[0002] Ultrasonic sensors are known that detect an object by transmitting and receiving ultrasonic waves. Specifically, this type of ultrasonic sensor transmits ultrasonic waves through a vibrating element, such as a piezoelectric element, which excites a membrane. This type of ultrasonic sensor then detects objects by converting the vibration of the membrane, which occurs when the waves are received and reflected by the object to which the ultrasonic wave was transmitted, into an electrical signal.

[0003] If the diaphragm in this type of ultrasonic sensor is covered with ice or snow in a low-temperature environment, the sensing performance of the ultrasonic sensor decreases. Therefore, it is common practice to provide a heater to heat the diaphragm (see, for example, US 2009 / 0211360A1).

[0004] Reference is also made to DE 10 2005 045 019 A1, WO 2017 / 054 930 A1, CN 1 03 471 633 A, DE 20 2007 007 135 U1 and US 4 450 430 A, which were identified as prior art. [Overview of the invention]

[0005] Adding a heater to an ultrasonic sensor to prevent or eliminate freezing and snow adhesion, as described in US 2009 / 0211360A1 and others, presents a disadvantage of increased manufacturing effort due to the increased number of components. The present disclosure was prepared with respect to the circumstances described above.

[0006] According to one aspect of the present disclosure, an ultrasonic sensor comprises: an ultrasonic transceiver including a vibrating element with a function for converting between mechanical vibration and an electrical signal, and a transceiver housing configured to cover the vibrating element; a sensor housing containing a control board electrically connected to and supporting the ultrasonic transceiver; and a shielding element electromagnetically shielding at least a portion of an electrical circuit, including the vibrating element and the control board, in at least five out of six directions, and having a first and a second end. The shielding element is formed in a thin-sheet or wire mesh form. The portion of the electrical circuit to be shielded includes at least the control board.The first end of the shielding element is configured to be constantly connected to a ground wire in order to electromagnetically shield at least part of the electrical circuit; and the second end is configured to be selectively connected to a power source, with the shielding element being configured to generate heat when powered while the second end is connected to the power source.

[0007] In the above configuration, the first end of the shielding element is configured to be permanently connected to a ground wire to shield at least part of the electrical circuit. Furthermore, the second end is configured to be selectively connected to a power source, with the shielding element being configured to generate heat when powered while the second end is connected to the power source.

[0008] This means that, in the configuration described above, the shielding element, which electromagnetically shields at least part of the electrical circuit, can act as a heater to prevent or eliminate freezing and snow accumulation. Therefore, this configuration makes it possible to prevent or eliminate freezing and snow accumulation in the ultrasonic sensor, while minimizing any increase in manufacturing costs due to an increase in the number of components.

[0009] Reference numerals in parentheses, which are assigned to elements, merely show examples of correspondences between the elements and specific units in embodiments described later. Thus, the present disclosure is not limited to the description of the reference numerals. [Brief description of the drawings] Fig. Figure 1 is a side cross-sectional view of a schematic device configuration of an ultrasonic sensor according to one embodiment. Fig. Figure 2 is a diagram illustrating a schematic circuit configuration of the main components of the ultrasonic sensor, which is used in Fig. 1 is illustrated. Fig. 3 is a flowchart illustrating an operational example of a control unit located in Fig. 2 is illustrated. Fig. Figure 4 is a side cross-sectional view of a schematic device configuration of an ultrasonic sensor according to a modification example. Fig. Figure 5 is a diagram illustrating a schematic circuit configuration in the main components of an ultrasonic sensor according to another modification example. Fig. 6 is a flowchart illustrating an operational example of a control unit located in Fig. 5 is illustrated. [Description of embodiments](design forms)

[0010] The following sections describe embodiments with reference to the drawings. Different modifications applicable to an embodiment are explained collectively after the description of the embodiment, as including the description of the modifications within the description of the embodiment could impair the understanding of the embodiment. (Entire configuration)

[0011] First, an overall configuration of an ultrasonic sensor 1 according to the present embodiment is described with reference to Fig. 1 described. As in Fig. As illustrated in Figure 1, the ultrasonic sensor 1 includes an ultrasonic wave transmitter / receiver 2, an elastic holding element 3, a damping element 4, a sensor box 5, an electrical circuit 6, a shielding element 7 and a filling material 8.

[0012] The ultrasonic wave transmitter 2 is enabled to transmit and receive ultrasonic waves. Specifically, the ultrasonic wave transmitter 2 is configured to transmit a test wave along a directional axis DA based on an applied drive signal and to receive a reflected wave from an object in the environment, generating a received signal. Hereinafter, a direction parallel to the directional axis DA is also referred to as an "axial direction." A "front end in the axial direction" corresponds to the top side in Fig. 1. A “base end face in the axial direction” corresponds to the underside in Fig. 1. Directions orthogonal to the axial direction are also referred to as "in-plane directions".

[0013] The ultrasonic wave transmitter 2 has a vibration element 21 and a transmitter / receiver box 22. The vibration element 21 is an electrical element that has a function to convert between mechanical vibration and an electrical signal, which is formed from a piezoelectric element or the like.

[0014] The transmitter-receiver housing 22 is designed to cover the vibrating element 21. In the present embodiment, the transmitter-receiver housing 22 has a cylindrical outer shape with a base having a central axis along the direction axis DA. In particular, the transmitter-receiver housing 22 has a diaphragm support element 23 and a diaphragm element 24. In the present embodiment, the transmitter-receiver housing 22 is integrally and seamlessly formed from a metal such as aluminum.

[0015] The diaphragm support element 23 is formed in a cylindrical shape extending along the directional axis DA. The diaphragm part 24 is a thin sheet metal part that blocks the front end of the diaphragm support element 23 in the axial direction and is designed to form an upper plate part of the transmitter-receiver housing 22.

[0016] The membrane back surface 25 serves as an inner surface of the membrane part 24, and the vibration element 21 is fixed to a substantially central part of the membrane back surface 25 in a corresponding in-plane direction; that is, the vibration element 21 is located on the front end of the ultrasonic wave transmitter 2 in the axial direction. The membrane part 24 is excited by vibration of the vibration element 21 due to the application of a control signal or by receiving a reflection wave, so that an outer edge portion, which is fixed and supported by the membrane support part 23, serves as a fixed end.

[0017] The elastic retaining element 3 is made of an elastic resin material such as silicone rubber, possessing insulating properties and elasticity. This elastic resin material is also known as a viscoelastic material or elastomer. The elastic retaining element 3 has a substantially cylindrical shape. It is configured to elastically support the ultrasonic wave transmitter 2 by covering its base end while leaving its front end exposed in the axial direction.

[0018] The damping element 4 is a disc-shaped element with an outer diameter corresponding to the inner diameter of the elastic retaining element 3. That is, the damping element 4 is embedded in a cylindrical space within the elastic retaining element 3, axially closer to the base end than the portion of the elastic retaining element 3 that supports the ultrasonic wave transmitter 2. The damping element 4 is made of a foamed elastic material, such as foamed silicone, with insulating properties and elasticity to suppress the transmission of vibration from the ultrasonic wave transmitter 2 to the sensor housing 5.

[0019] The sensor box 5, which forms the housing of the ultrasonic sensor 1, is configured to hold the base end part of the elastic retaining element 3 in the axial direction. That is, the ultrasonic wave transmitter 2 is supported by the sensor box 5 by means of the elastic retaining element 3.

[0020] In the present embodiment, the sensor box 5 has a main body part 51, a connector part 52, and a tube part 53. The sensor box 5 is integrally formed from a rigid synthetic resin such as polypropylene.

[0021] The main body section 51 is a box-like part with a substantially rectangular parallelepiped shape and is formed as a cylindrical shape with a base in which the base end is open in the axial direction. The connector section 52 extends outwards from a side wall section of the main body section 51 to electrically connect the ultrasonic sensor 1 to an external device such as an electronic control unit.

[0022] The box tube section 53 is a substantially cylindrical part that projects axially from the main box body section 51 towards its front end. The cylindrical space within the box tube section 53 is designed to communicate with the substantially rectangular parallelepiped space within the main box body section 51. Hereinafter, the portion of the space within the box tube section 53, excluding the section occupied by the damping element 4, and the space within the main box body section 51 are collectively referred to as the space within the sensor box 5.

[0023] The space inside the sensor box 5 accommodates a control board 60 and a wiring section 61, which together form the electrical circuit 6, and a shielding element 7. That is, the sensor box 5 is configured to elastically support the ultrasonic wave transmitter 2, while simultaneously supporting the wiring section 61 and the control board 60, which is electrically connected to the ultrasonic wave transmitter 2 via the wiring section 61.

[0024] The electrical circuit 6, which is formed within the ultrasonic sensor 1, includes the vibration element 21, the control board 60 and the wiring part 61. The control board 60 has several electrical circuit elements including a control circuit unit 62 and a temperature sensor 63.

[0025] The control circuit unit 62 is designed to control the operations of the ultrasonic sensor 1. Specifically, the control circuit unit 62 is configured to control transmit and receive operations performed by the ultrasonic wave transmitter 2 based on control signals received from an external device, such as an electronic control unit. The control circuit unit 62 is configured to send an object detection signal to an external device in response to a received signal obtained through transmit and receive operations performed by the ultrasonic wave transmitter 2. The temperature sensor 63 is designed to generate an output indicating the temperature of the ultrasonic sensor 1 (for example, a voltage).

[0026] In the present embodiment, the shielding element 7 is provided in the sensor housing 5 for electromagnetic shielding at least a part of the electrical circuit 6. In particular, the shielding element 7 is fixed to the inner surface of the sensor housing 5 to cover the control board 60 and the wiring section 61, which extends axially from the damping element 4 to the base end in the space inside the sensor housing 5.

[0027] The shielding element 7 is configured to perform both the electromagnetic shielding and heat generation functions. In particular, in the present embodiment, the shielding element 7 is formed in a thin sheet or wire mesh form from a metal resistor such as a nickel-chromium alloy. The electrical connection of the shielding element 7 is described later.

[0028] The space inside the sensor box 5 is filled with a filling material 8 such as silicone rubber with insulating properties and elasticity. (Circuit configuration)

[0029] Fig. Figure 2 schematically illustrates a circuit configuration of the electrical circuit 6 when the ultrasonic sensor 1 is electrically connected to a power source B according to the present embodiment. Fig. 2 is a first terminal 71, which is one end of a current-flow path of the shielding element 7, permanently electrically connected to a ground wire G. A second terminal 72, which is the other end of the current-flow path of the shielding element 7, is electrically connected to the power source B in a selective manner. Specifically, the shielding element 7 is configured to generate heat when it is powered while the second terminal 72 is connected to the power source B, and the shielding element 7 is configured not to generate heat while the second terminal 72 is connected to the ground wire G.

[0030] As described above, the first terminal 71 of the shielding element is configured to be permanently connected to a ground wire G to electromagnetically shield at least part of the electrical circuit 6; and the second terminal 72 is configured to be selectively connectable to a power source B, with the shielding element being configured to generate heat when powered while its second end is connected to the power source. A specific configuration example of how the second terminal 72 is alternatively connected to either the power source B or the ground wire G is described below.

[0031] In the present embodiment, the control circuit unit 62 has a control unit 620, a transmitting circuit 621, a receiving circuit 622 and a heater switch 623.

[0032] The control unit 620 is electrically connected to the transmitter circuit 621 for controlling the transmitter circuit 621 to output a control signal. The transmitter circuit 621 is electrically connected to the vibrating element 21 for outputting a control signal to the vibrating element 21 under the control of the control unit 620. The transmitter-receiver box 22 is permanently electrically connected to the ground wiring G by a constant electrical connection to a reference electrode, that is, a ground-side electrode in the vibrating element 21.

[0033] The receiving circuit 622 is electrically connected to the vibrating element 21 for signal processing, such as amplification of the received signal generated by the vibrating element 21 through the reception of a reflection wave by the ultrasonic wave transmitter 2. The control unit 620 is electrically connected to the receiving circuit 622 to receive the received signal from the receiving circuit 622 after it has undergone signal processing.

[0034] The control unit 620 is electrically connected to the temperature sensor 63 to receive an output corresponding to the temperature of the ultrasonic sensor 1 from the temperature sensor 63. The control unit 620 is electrically connected to the heater switch 623 to control the power supply state of the shielding element 7 according to the temperature of the ultrasonic sensor 1, which is detected by the temperature sensor 63. The heater switch 623 is provided to electrically connect the second terminal 72 to one of the power source B and the ground wiring G in an alternative manner under the control of the control unit 620. (Beneficial effects)

[0035] The following is an overview of operations in the configuration according to the present embodiment, together with a description of advantageous effects produced by the configuration, with reference to the drawings.

[0036] In the present embodiment, the shielding element 7 has its first terminal 71 permanently electrically connected to the ground wiring G. Consequently, the shielding element 7 covers and electromagnetically shields at least a portion of the electrical circuit 6, in particular the control board 60 and the wiring section 61. The vibration element 21 in the electrical circuit 6 is electromagnetically shielded by the grounded metallic transceiver housing 22. The second terminal 72 is configured to be selectively connected to a power source B, with the shielding element 7 being configured to generate heat when powered while the second terminal 72 is connected to the power source B.

[0037] This means that, in the configuration described above, the shielding element 7, which electromagnetically shields at least part of the electrical circuit 6, can act as a heater to prevent or eliminate freezing and snow accumulation. Therefore, according to this configuration, it is possible to prevent or eliminate freezing and snow accumulation in the ultrasonic sensor 1, while minimizing any increase in manufacturing costs due to an increase in the number of components.

[0038] In the present embodiment, the shielding element 7 is configured to generate heat when powered while the second terminal 72 is connected to the power source B, and the shielding element 7 is configured not to generate heat while the second terminal 72 is connected to the ground wire G. That is, the shielding element 7 is configured not to generate heat while both the first terminal 71 and the second terminal 72 are connected to the ground wire G. Therefore, according to this configuration, the control board 60 and the like can preferably be electrically shielded even using the shielding element 7, which is formed from a resistive element.

[0039] The ultrasonic sensor 1 detects environmental objects by transmitting / receiving ultrasonic waves through the ultrasonic wave transmitter 2, provided a predetermined object detection operating condition is met. In the present embodiment, the control unit 620 supplies power to the shielding element 7 while the object detection operating condition of the ultrasonic sensor 1 is not met. This preferably prevents or eliminates the freezing and adhesion of snow in the ultrasonic sensor 1 without adversely affecting its object detection operation.

[0040] In the present embodiment, the control unit 620 controls the power supply state of the shielding element 7 based on an output from the temperature sensor 63. Specifically, the control unit 620 controls the power supply state of the shielding element 7 in order to change the amount of heat to be generated by the shielding element 7 according to a difference between a temperature T of the ultrasonic sensor 1, detected by the temperature sensor 63, and a predetermined reference temperature TF. This results in correct control of heat generation in the shielding element 7 according to the temperature of the ultrasonic sensor 1, i.e., the ambient temperature.

[0041] Fig. Figure 3 is a flowchart showing an example of power supply control operations performed by control unit 620 for shielding element 7. In the drawing and the following description, the term "step" is abbreviated as "S". This also applies to the section described later in Fig. 6 flowcharts shown.

[0042] Since a system equipped with the ultrasonic sensor 1 is switched on, for example, when the ignition switch is turned on, the control unit 620 repeatedly activates a power supply control routine which is in Fig. 3 is shown, at predetermined time intervals. If the feed control routine, which is in Fig. As shown in 3, when activated, the control unit 620 at S310 first determines whether the object detection operation condition is met.

[0043] If the object detection operation condition is met (YES at S310), the control unit 620 proceeds with processing to S320 and then terminates this routine. At S320, the control unit 620 prohibits electrical connection between the shielding element 7 and the power source B. Consequently, the heater operation of the shielding element 7 is switched off. On the other hand, if the object detection operation condition is not met (NO up to S310), the control unit 620 continues with its processing to S330 and S331.

[0044] In S330, the control unit 620 obtains the temperature T of the ultrasonic sensor 1 based on an output from the temperature sensor 63. In S331, the control unit 620 determines whether the temperature T obtained in S330 is lower than the reference temperature TF.

[0045] If the temperature T is equal to or greater than the reference temperature TF (NO at S331), the control unit 620 continues its processing to S320 and then temporarily terminates this routine. That is, in this case, the control unit 620 prohibits electrical connection between the shielding element 7 and the power source B. Consequently, the heater operation of the shielding element 7 is switched off.

[0046] If the temperature T is lower than the reference temperature TF (JA in S331), the control unit 620 continues with its processing to S340 and the subsequent steps. That is, at S340, the control unit 620 allows an electrical connection between the shielding element 7 and the power source B. Consequently, the heater operation is switched on by the shielding element 7. The control unit 620 also performs heat generation control according to the temperature T of the ultrasonic sensor 1 through the processing at S341 and the subsequent steps.

[0047] In particular, in S341, the control unit 620 first determines whether the temperature T is lower than the temperature TL1, where TL1 < TF.

[0048] If the temperature T is equal to or greater than the temperature TL1 (NO at S341), the control unit 620 continues its processing to S342 and then temporarily terminates this routine. At S342, the control unit 620 sets the heat generation amount W to W1. Specifically, the control unit 620 adjusts the magnitude or duty cycle of the current flowing through the shielding element 7 such that the heat generation amount W of the shielding element 7 becomes W1.

[0049] If the temperature T is lower than the temperature TL1 (YES in S341), the control unit 620 continues its processing with S343. In S343, the control unit 620 determines whether the temperature T is lower than a temperature TL2, where TL2 < TL1.

[0050] If the temperature T is equal to or greater than the temperature TL2 (NO at S343), the control unit 620 continues its processing with S344 and then temporarily terminates this routine. At S344, the control unit 620 sets the heat generation amount W to W2, where W1 < W2.

[0051] If the temperature T is less than the temperature TL2 (YES at S343), the control unit 620 continues its processing to S345 and then temporarily terminates this routine. At S345, the control unit 620 sets the heat generation amount W to W3, where W2 < W3. (Modification example)

[0052] The present disclosure is not limited to the foregoing embodiments. Accordingly, the foregoing embodiments may be suitably modified. Typical examples of modification are described below. The following examples of modification will focus on differences from the preceding embodiments. In the embodiments and the examples of modification, identical or equivalent parts are designated with the same reference numerals. Therefore, in the following description of the examples of modification, the foregoing descriptions relating to the embodiments will be included for the components with the same reference numerals as in the preceding embodiments, unless there are technical inconsistencies or a specific additional specification.

[0053] The ultrasonic sensor 1 is not limited to a configuration that can both transmit and receive ultrasonic waves. That is, the ultrasonic sensor 1 can, for example, only transmit ultrasonic waves. Conversely, the ultrasonic sensor 1 can also have a function for receiving reflection waves from surrounding objects to which test waves were transmitted as ultrasonic waves by other ultrasonic transmitters.

[0054] The configurations of components of the ultrasonic sensor 1 are not limited to the specific examples given above. In particular, for example, the external shape of the ultrasonic wave transmitter / receiver 2 is not limited to a substantially circular column, but can be a substantially hexagonal column, an substantially octagonal column, or the like. The vibration element 21 is not limited to a piezoelectric element, but can be a static capacitance element.

[0055] In the foregoing embodiments, the shielding element 7 is provided in the sensor box 5 primarily to heat the sensor box 5. In particular, the shielding element 7 is fixed to the inner surface of the sensor box 5. However, the present disclosure is not limited to this mode.

[0056] In an ultrasonic sensor 1 according to a modification example that is in Fig. As illustrated in Figure 4, the transmitter-receiver housing 22 is integrally and seamlessly formed from an insulating synthetic resin. A transmitter-receiver shielding element 700 is embedded in the transmitter-receiver housing 22, which is made of an insulating synthetic resin.

[0057] In the present modification example, the transmitter-receiver shielding element 700 is a coil-like electrical heating wire formed from a metallic resistance element such as a nickel-chromium alloy and surrounding the directional axis DA. The transmitter-receiver shielding element 700 is provided in the membrane support part 23.

[0058] In the configuration of the present modification example, the ultrasonic wave transmitter 2 in the ultrasonic sensor 1, which is likely to be closest to cold air, is preferably heated by the transmitter-receiver shielding element 700. Therefore, according to this configuration, it is preferably possible to prevent or eliminate freezing and snow adhesion in the ultrasonic sensor 1.

[0059] In the configuration of the modification example, which is in Fig. As illustrated in Figure 4, the shielding element 7, which is provided on the sensor box 5, can be omitted. That is, the ultrasonic sensor 1 can be heated by only the transmitter-receiver shielding element 700.

[0060] The transmitter-receiver shielding element 700 can be provided in the membrane part 24, provided that the function of the ultrasonic wave transmitter-receiver 2 for transmitting and receiving ultrasonic waves is adversely affected. In particular, for example, the transmitter-receiver shielding element 700 can be provided in the membrane part 24 on an outer edge part that is connected to the membrane support part 23.

[0061] The transmitter-receiver shielding element 700 can be provided in the membrane support part 23 or the membrane part 24. Alternatively, the transmitter-receiver shielding element 700 can be provided to cross the membrane support part 23 and the membrane part 24.

[0062] Shielding element 7 can be divided into several split shielding elements. Similarly, in the configuration of the modification example shown in Fig. Figure 4 illustrates that the shielding element 7, provided on the side of the sensor box 5, and the transmitter-receiver shielding element 700 can each be considered as forming several divided shielding elements. There is no definite limit to the number of subdivisions N of the shielding element 7, where N represents an integer of 2 or more. That is to say, the configuration of the modification example shown in Figure 4 can be considered as follows: Fig. Figure 4 illustrates the case where N = 2.

[0063] Fig. Figure 5 illustrates a circuit configuration example of the shielding element 7, which is divided into three subdivided shielding elements, namely a first shielding element 701, a second shielding element 702, and a third shielding element 703. As shown in Fig. As illustrated in Figure 5, the control circuit unit 62 has the same number of heater switches 623 as the number of divided shielding elements, that is, three heater switches 623 arranged in parallel between the power source B and the ground wiring G.

[0064] The control unit 620 is designed to individually control the respective power supply states of the several subdivided shielding elements, namely the first shielding element 701, the second shielding element 702, and the third shielding element 703. In particular, the control unit 620 is configured to control the presence or absence of power supply to each of the first shielding element 701, the second shielding element 702, and the third shielding element 703 according to the difference between the temperature T of the ultrasonic sensor 1, detected by the temperature sensor 63, and the predetermined reference temperature TF.

[0065] Fig. Figure 6 illustrates an operational example of the configuration that is in Fig. 5 is illustrated. According to Fig. 6 the expression “Heizer H1” corresponds to the first shielding element 701, “Heizer H2” corresponds to the second shielding element 702 and “Heizer H3” corresponds to the third shielding element 703.

[0066] If the feed control routine, which is in Fig. As shown in Figure 6, when the process is started, the control unit 620 at S610 first determines whether the object detection operation condition is met.

[0067] If the object detection operation condition is met (YES at S610), the control unit 620 proceeds with processing S615 and then terminates this routine. At S615, the control unit 620 prohibits the respective electrical connections of the first shielding element 701, the second shielding element 702, and the third shielding element 703 with the power source B. Consequently, the respective heater operations of the first shielding element 701, the second shielding element 702, and the third shielding element 703 are deactivated.

[0068] If the object detection operation condition is not met (NO up to S610), the control unit 620 continues its processing with S630 and S631.

[0069] In S630, the control unit 620 obtains the temperature T of the ultrasonic sensor 1 based on the output of the temperature sensor 63. In S631, the control unit 620 determines whether the temperature T obtained in S630 is lower than the reference temperature TF.

[0070] If the temperature T is equal to or greater than the reference temperature TF (NO for S631), the control unit 620 continues its processing with S615 and then temporarily terminates this routine. That is, in this case, the control unit 620 prohibits the respective electrical connections of the first shielding element 701, the second shielding element 702, and the third shielding element 703 with the power source B. Consequently, the respective heater operations of the first shielding element 701, the second shielding element 702, and the third shielding element 703 are deactivated.

[0071] If the temperature T is lower than the reference temperature TF (YES in S631), the control unit 620 continues its processing with S650 and S651. At S650, the control unit 620 electrically connects the first shielding element 701 to the power source B. Consequently, the heating operation of the first shielding element 701 is activated. Next, at S651, the control unit 620 determines whether the temperature T is lower than the temperature TL1, where TL1 < TF.

[0072] If the temperature T is equal to or greater than the temperature TL1 (NO at S651), the control unit 620 continues its processing with S652 and then temporarily terminates this routine. At S652, the control unit 620 prohibits the respective electrical connections of the second shielding element 702 and the third shielding element 703 with the power source B. Consequently, the respective heating operations of the second shielding element 702 and the third shielding element 703 are deactivated. That is, if the temperature T is lower than the reference temperature TF and equal to or greater than the temperature TL1, of the first shielding element 701, the second shielding element 702, and the third shielding element 703, only the first shielding element 701 is powered.

[0073] If the temperature T is lower than the temperature TL1 (YES at S651), the control unit 620 continues its processing with S653 and S654. At S653, the control unit 620 electrically connects the second shielding element 702 to the power source B. Consequently, the heater operation of the second shielding element 702 is activated. Next, at S654, the control unit 620 determines whether the temperature T is lower than the temperature TL2, where TL2 < TL1.

[0074] If the temperature T is equal to or greater than the temperature TL2 (NO at S654), the control unit 620 continues its processing with S655 and then temporarily terminates this routine. At S655, the control unit 620 prohibits the electrical connection of the third shielding element 703 to the power source B. Consequently, the respective heating operations of the first shielding element 701 and the second shielding element 702 are activated, while the heating operation of the third shielding element 703 is deactivated. That is, if the temperature T is lower than the temperature TL1 and equal to or greater than the temperature TL2, the first shielding element 701, the second shielding element 702, and the third shielding element 703 are powered.

[0075] If the temperature T is lower than the temperature TL2 (YES at S654), the control unit 620 continues its processing with S656 and then temporarily terminates this routine. At S656, the control unit 620 electrically connects the third shielding element 703 to the power source B. Consequently, the heating operation of the third shielding element 703 is activated. That is, in this case, the first shielding element 701, the second shielding element 702, and the third shielding element 703 are all powered.

[0076] Through a combination of the configuration that is in Fig. 4 is illustrated, and the configuration shown in Fig.As illustrated in Figure 5, the control unit 620 can be configured to control the power supply states of the shielding element 7, located on the side of the sensor box 5, and the transmitter-receiver shielding element 700, depending on the temperature T. In particular, the control unit 620 can be configured to switch between a first mode in which only the shielding element 7, located on the sensor box 5, generates heat; a second mode in which only the transmitter-receiver shielding element 700 generates heat; and a third mode in which both generate heat, depending on the temperature.

[0077] The ultrasonic sensor 1 does not necessarily have to include the temperature sensor 63. In this case, the temperature sensor 63 can be mounted in a system (e.g., a vehicle) that is equipped with the ultrasonic sensor 1 in a different position than the ultrasonic sensor 1. In particular, the temperature sensor 63 could, for example, be an outside air temperature sensor in a vehicle air conditioning system. Alternatively, the temperature sensor 63 could be an intake air temperature sensor in a vehicle with an internal combustion engine.

[0078] In each of the specific examples described above, the control unit 620 is mounted in the ultrasonic sensor 1 to control the supply state, that is, the heat-generating state of the shielding element 7. Therefore, in a case where the system is equipped with multiple ultrasonic sensors 1, it is possible to perform preferential heater control according to differences in the status between the multiple ultrasonic sensors 1. That is, for example, it is possible to perform autonomous heater control according to a difference in ambient temperature between the ultrasonic sensor 1 located on a sunlit part of the vehicle and the ultrasonic sensor 1 located on a shaded part of the vehicle.

[0079] However, the present disclosure is not limited to the aforementioned mode. In particular, for example, the control unit 620, which controls the supply state, that is, the heat-generating state of the shielding element 7, can be provided in an external device such as an electronic control unit, which is electrically connected to several ultrasonic sensors 1. That is, the several ultrasonic sensors 1 can be subjected to central heater control by an external device such as an electronic control unit.

[0080] The multiple components described above as integrally formed in a seamless manner can be formed by joining several separate elements together. Similarly, multiple components formed by attaching separate elements to one another can be integrally formed in a seamless manner.

[0081] The multiple components described above as being made of the same material can be made of different materials. Similarly, multiple components made of different materials can also be made of the same material.

[0082] It is obvious that the elements constituting the foregoing embodiment are not necessarily essential unless they are expressly designated as essential or are generally and unambiguously considered to be essential. When the numbers, values, quantities, and ranges of the components are specified, the present disclosure is not limited to these values ​​unless these values ​​are clearly described as essential and the components are generally and unambiguously limited to these specific values.When the forms, directions, positional relationships, and other constituent elements are specified, the present disclosure is not limited to these forms, directions, positional relationships, and others unless these forms, directions, positional relationships, and others are clearly described to be essential and the constituent elements are limited in principle to the forms, directions, positional relationships, and others.

[0083] The modification example is not limited to the preceding examples. Furthermore, several modification examples can be combined. All or some parts of the preceding embodiments can be combined with all or some parts of any modification example.

Claims

[1] Ultrasonic sensor (1) comprising: an ultrasonic wave transmitter receiver (2) comprising a vibration element (21) with a function for converting between mechanical vibration and an electrical signal and a transmitter receiver box (22) configured to cover the vibration element (21); a sensor box (5) which accommodates a control board (60) which is electrically connected to the ultrasonic wave transmitter (2), and carries the ultrasonic wave transmitter (2); and a shielding element (7) which electromagnetically shields at least a part of an electrical circuit (6) including the vibration element (21) and the control board (60) in at least five of six directions and has a first end (71) and a second end (72), wherein the shielding element (7) is designed in a thin sheet metal or wire mesh form; the part of the electrical circuit (6) to be shielded includes at least the control board (60); the first end (71) of the shielding element (7) is configured to be permanently connected to a ground wire (G) in order to electromagnetically shield at least part of the electrical circuit (6); and the second end (72) is configured to be selectively connected to a power source (B), wherein the shielding element (7) is configured to generate heat when it is powered while the second end (72) is connected to the power source (B). [2] Ultrasonic sensor (1) according to claim 1, wherein the shielding element (7) is configured to generate heat when powered, while the second end (72) is connected to the power source (B), and the shielding element (7) is configured to not generate heat, while the second end (72) is connected to the ground wiring (G). [3] Ultrasonic sensor (1) according to claim 1 or 2, wherein the shielding element (7) is provided in the sensor box (5) to cover the control board (60). [4] Ultrasonic sensor (1) according to any one of claims 1 to 3, wherein the shielding element (7) is embedded in the transmitter receiver box (22), wherein the transmitter receiver box (22) is made of an insulating synthetic resin. [5] Ultrasonic sensor (1) according to one of claims 1 to 4, further comprising a control unit (620) which controls a power supply state of the shielding element (7). [6] Ultrasonic sensor (1) according to claim 5, wherein the control unit (620) is configured to power the shielding element (7) while an object detection operation condition of the ultrasonic sensor (1), under which the ultrasonic sensor (1) detects environmental objects, is not met. [7] Ultrasonic sensor (1) according to claim 5 or 6, wherein the control unit (620) is configured to control the power state of the shielding element (7) based on an output from a temperature sensor (63) which generates the output indicating a temperature of the ultrasonic sensor (1). [8] Ultrasonic sensor (1) according to claim 7, wherein the control unit (620) is configured to control the power state of the shielding element (7) in order to change an amount of heat to be generated by the shielding element (7) according to a difference between the temperature and a predetermined reference temperature. [9] Ultrasonic sensor (1) according to claim 8, wherein the shielding element (7) consists of several subdivided shielding elements (701 to 703), and the control unit (620) is configured to individually control respective power states of the several subdivided shielding elements (701 to 703).

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