Ultrasonic sensor and fault detection device

Abstract

The present application provides an ultrasonic sensor and a fault detection device for detecting an object to be detected. The ultrasonic sensor includes at least one piezoelectric unit, which is arranged on the axial side of the object to be detected. The piezoelectric unit includes a first section and a second section. The first section is elliptical, and the second section is in the same plane as the first section. The second section is connected to the first section and bulges toward a side away from the first section at a sharp angle, so that the piezoelectric unit emits a beam along a first direction to detect a section of the object to be detected close to the ultrasonic sensor, and the piezoelectric unit emits a beam along a second direction to detect a section of the object to be detected far from the ultrasonic sensor. By setting the piezoelectric unit to a specific shape, the piezoelectric unit is non-uniformly excited and forms an eccentric fan-shaped ultrasonic sound field, so that beams are emitted toward the object to be detected in two directions, and the object to be detected is detected without disassembling and disassembling the equipment. The detection operation is simpler and more convenient, and the work efficiency is improved.

Description

Technical Field

[0001] The present application belongs to the field of sensor technology, and specifically relates to an ultrasonic sensor and a fault detection device. Background Art

[0002] During the operation of a hydroelectric generator set, the turbine top cover bolts may be fatigued and break, thus causing a "flooded plant" accident. Ultrasonic sensors are usually used to detect fatigue cracks inside the bolts. Conventional ultrasonic sensors can only emit a main beam toward the center axis of the bolt when detecting bolt damage. Due to the long length of the bolt, the propagation path of the beam inside the bolt is limited, and only the section of the bolt close to the ultrasonic sensor can be detected, resulting in insignificant fatigue crack detection effect on the section of the bolt far from the ultrasonic sensor.

[0003] Usually, the bolts need to be disassembled and removed, and tested from both end faces to ensure that all fatigue cracks inside the bolts are detected. However, the turbine cover bolts can only be disassembled and removed during the overhaul of the unit (15 to 30 years). The bolts cannot be removed during long-term operation. Conventional ultrasonic detection sensors cannot reliably detect fatigue cracks in the bolts. Therefore, there is an urgent need for a sensor that can emit multiple main beams in different directions of the bolts to reliably detect fatigue cracks inside the bolts without disassembling the turbine. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide an ultrasonic sensor and a fault detection device, wherein the ultrasonic sensor can emit beams in two directions toward the object to be detected, so as to detect the object to be detected without disassembling and dismantling the equipment, so as to make the detection result more reliable and improve work efficiency.

[0005] In order to solve the above problems, the present application provides an ultrasonic sensor for detecting an object to be detected, the ultrasonic sensor comprising at least one piezoelectric unit, the piezoelectric unit being arranged on the axial side of the object to be detected, the piezoelectric unit comprising a first section and a second section, the first section being elliptical, the second section being in the same plane as the first section, the second section being connected to the first section, and protruding at a sharp angle toward a side away from the first section, so that the piezoelectric unit emits a beam along a first direction to detect a section of the object to be detected that is close to the ultrasonic sensor, and the piezoelectric unit emits a beam along a second direction to detect a section of the object to be detected that is away from the ultrasonic sensor.

[0006] Optionally, the first direction is the axial direction of the object to be detected, and the second direction is a direction toward the outer peripheral wall of the object to be detected and forming an angle a with the first direction, 6°≤a≤12°.

[0007] Optionally, the first section of the piezoelectric unit is located on a side of the second section away from the central axis of the object to be detected, and the major axis of the ellipse of the first section is perpendicular to the angular bisector of the second section.

[0008] Optionally, the tip of the second section of the piezoelectric unit is arranged toward the central axis of the object to be detected.

[0009] Optionally, the tip angle of the second section of the piezoelectric unit is b, 40°≤b≤60°;

[0010] The first section of the piezoelectric unit has an elliptical shape with a major axis length of L1 and a minor axis length of L2, and a ratio of the major axis length L1 to the minor axis length L2 is (2.4-2.6):1;

[0011] The length of the junction between the first section and the second section of the piezoelectric unit is L3, 22mm≤L3≤33mm;

[0012] The maximum length of the first section and the second section of the piezoelectric unit 1 in the arrangement direction is L4, 28mm≤L4≤42mm;

[0013] The thickness of the piezoelectric unit is L5, 90 μm≤L5≤110 μm.

[0014] Optionally, a plurality of the piezoelectric units are provided, and the plurality of the piezoelectric units are evenly arranged along the circumferential direction of the central axis of the object to be detected.

[0015] Optionally, four piezoelectric units are provided, and the four piezoelectric units are symmetrically arranged along the circumferential direction of the central axis of the object to be detected.

[0016] Optionally, the ultrasonic sensor further includes a damping block, which is disposed on a side of the piezoelectric unit away from the object to be detected, and the damping block is connected to the piezoelectric unit.

[0017] Optionally, the ultrasonic sensor further includes a shell, a signal transmitting unit and a signal receiving unit, the signal transmitting unit and the signal receiving unit are electrically connected to the piezoelectric unit, and the signal transmitting unit and the signal receiving unit are arranged in the shell.

[0018] In another aspect of the present application, a fault detection device is provided, comprising any one of the ultrasonic sensors described above.

[0019] Beneficial Effects

[0020] An ultrasonic sensor and fault detection device are provided in an embodiment of the present invention, wherein the ultrasonic sensor sets a piezoelectric unit in a specific shape so that the piezoelectric unit can be non-uniformly excited and forms an eccentric fan-shaped ultrasonic sound field, emitting main beams in two directions toward the inside of the object to be detected, the beam in the first direction is used to detect damage defects in a section of the object to be detected close to the ultrasonic sensor, and the beam in the second direction is used to detect damage defects in a section of the object to be detected away from the ultrasonic sensor. The internal defects of the object to be detected can be reliably detected, and the accuracy of the detection is improved. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, thereby reducing the intensity of manual labor, shortening the detection period, improving the availability of the equipment, further improving the work efficiency, and being able to detect the object to be detected at any time, reducing the accident rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of an ultrasonic sensor according to an embodiment of the present application;

[0022] Figure 2 Schematic diagram of the structure of the piezoelectric unit according to an embodiment of the present application.

[0023] The reference numerals are:

[0024] 1. Piezoelectric unit; 11. First section; 12. Second section; 2. Damping block; 3. Housing; 4. Signal transmitting unit; 5. Signal receiving unit. DETAILED DESCRIPTION

[0025] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0027] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] See also Figure 1 to Figure 2 As shown, according to an embodiment of the present application, the present application provides an ultrasonic sensor for detecting an object to be detected, the ultrasonic sensor includes at least one piezoelectric unit 1, the piezoelectric unit 1 is arranged on the axial side of the object to be detected, the piezoelectric unit 1 includes a first section 11 and a second section 12, the first section 11 is elliptical, the second section 12 and the first section 11 are in the same plane, the second section 12 is connected to the first section 11, and is convex at a sharp angle to the side away from the first section 11, so that the piezoelectric unit 1 emits a beam along a first direction to detect a section of the object to be detected close to the ultrasonic sensor, and the piezoelectric unit 1 emits a beam along a second direction to detect a section of the object to be detected far from the ultrasonic sensor. The ultrasonic sound field emitted by the piezoelectric unit 1 can be approximately regarded as all piezoelectric microcrystals, as the result of the interference of multiple emission sound sources. By designing the shape of the piezoelectric unit 1, the sound field shape and direction of the ultrasonic wave can be changed. The present application sets the first section 11 of the piezoelectric unit 1 to be elliptical and the second section 12 to be roughly triangular, so that the piezoelectric unit 1 can be non-uniformly excited and form an eccentric fan-shaped ultrasonic sound field, emitting main beams in two directions toward the object to be detected. The beam in the first direction is used to detect damage defects in a section of the object to be detected close to the ultrasonic sensor, and the beam in the second direction is used to detect damage defects in a section of the object to be detected away from the ultrasonic sensor. The internal defects of the object to be detected can be reliably detected, and the accuracy of the detection is improved. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, thereby reducing the intensity of manual labor, shortening the detection period, improving the availability of equipment, further improving work efficiency, and being able to detect the object to be detected at any time, reducing the accident rate.

[0030] The ultrasonic sensor may be arranged directly above the object to be detected, and the cross-sectional area of ​​the object to be detected is smaller than the coverage range of the ultrasonic sensor, so that the ultrasonic sensor can fully detect the defects inside the object to be detected, thereby making the detection result more accurate.

[0031] Specifically, the ultrasonic sensor is fixed on the upper end surface to be detected and works continuously, which improves the signal-to-noise ratio and resolution of the ultrasonic sensor, while also improving the transmitting power and receiving sensitivity of the ultrasonic sensor, facilitating digital processing of the received signal, and further improving the signal-to-noise ratio and resolution of the ultrasonic sensor received signal.

[0032] The piezoelectric unit 1 may be arranged horizontally, and the second section 12 and the first section 11 of the piezoelectric unit 1 are in the same plane.

[0033] Among them, the piezoelectric unit 1 can be a piezoelectric ceramic crystal material. In the embodiment of the present application, the piezoelectric unit 1 is an iron-platinum-manganese-calcium quaternary doped modified (PZT-4) polycrystalline piezoelectric ceramic, and the structure of the piezoelectric unit 1 is a single layer.

[0034] Among them, the strain constant of the piezoelectric unit 1 can be 289×10-12m / V.

[0035] Specifically, the piezoelectric unit 1 can convert the emitted electrical pulse signal into an ultrasonic signal, and convert the received ultrasonic signal into an electrical signal.

[0036] The ultrasonic wave type emitted by the piezoelectric unit 1 may be a longitudinal wave, and the center frequency may be 5 MHz.

[0037] Among them, the piezoelectric unit 1 is irregular in shape, the first section 11 of the piezoelectric unit 1 is roughly elliptical, and the second section 12 of the piezoelectric unit 1 is roughly triangular. In the embodiment of the present application, the piezoelectric unit 1 can be an integrally formed structure. Through the irregular shape of the piezoelectric unit 1, the piezoelectric unit 1 can be non-uniformly excited by the electric pulse signal and form an eccentric fan-shaped ultrasonic sound field. Through the eccentric fan-shaped ultrasonic sound field, the detection range of the ultrasonic sensor is expanded, so that a section of the object to be detected far away from the ultrasonic sensor can also be detected, so that the detection range is more sufficient and the detection result is more reliable.

[0038] Specifically, the piezoelectric unit 1 can emit main beams in two directions toward the object to be detected, wherein the beam in the first direction is used to detect internal defects in a section of the object to be detected close to the ultrasonic sensor, and the beam in the second direction is used to detect internal defects in a section of the object to be detected far from the ultrasonic sensor, so as to avoid the piezoelectric unit 1 emitting a beam in only one direction, whose beam has a limited propagation path in the object to be detected and cannot detect a section of the object to be detected far from the ultrasonic sensor. By emitting beams in two directions by the piezoelectric unit 1, the detection of the object to be detected can be more complete, the detection effect is improved, and the accuracy of the detection result is improved. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, thereby reducing the intensity of manual labor, shortening the detection period, improving the availability of equipment, further improving work efficiency, and being able to detect the object to be detected at any time, reducing the accident rate.

[0039] Among them, one or more piezoelectric units 1 can be provided, and the multiple piezoelectric units 1 can emit multiple main beams in the first direction and the second direction to make the detection effect more accurate.

[0040] The first direction is the axial direction of the object to be detected, and the second direction is a direction toward the outer peripheral wall of the object to be detected and forming an angle a with the first direction, 6°≤a≤12°.

[0041] The ultrasonic sensor may be arranged directly above the object to be detected, and the ultrasonic beam in the first direction may be emitted vertically downward. The first direction may be the axial direction of the object to be detected or a direction parallel to the axial direction of the object to be detected.

[0042] Among them, the ultrasonic beam in the second direction can be emitted toward the outer wall of the object to be detected, the second direction has a certain angle with the first direction, the beam in the second direction can be obliquely emitted into the object to be detected, and the second direction intersects with the axial direction to be detected or the parallel line direction of the axis of the object to be detected.

[0043] Among them, the angle range between the second direction and the first direction is between 6° and 12°. In the embodiment of the present application, the object to be detected is a bolt, and the angle between the second direction and the first direction is most preferably 8°, which can enable the ultrasonic sensor to detect the entire bolt, so the detection effect is more sufficient and the accuracy of the detection result is improved.

[0044] Specifically, the ultrasonic wave has a limited propagation path in the object to be detected. The ultrasonic beam in the first direction is used to detect defects in a section of the object to be detected close to the ultrasonic sensor, and the ultrasonic beam in the second direction is used to detect defects in a section of the object to be detected far from the ultrasonic sensor. The beam in the first direction and the beam in the second direction can be used to detect the object to be detected as a whole, avoiding missed detections and improving the accuracy of the detection results. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, reducing the intensity of manual labor, shortening the detection period, improving the availability of equipment, further improving work efficiency, and being able to detect the object to be detected at any time, reducing the accident rate.

[0045] The first section 11 of the piezoelectric unit 1 is located on a side of the second section 12 away from the central axis of the object to be detected, and the major axis of the ellipse of the first section 11 is perpendicular to the angular bisector of the second section 12 .

[0046] The piezoelectric unit 1 is arranged horizontally, the plane where the piezoelectric unit 1 is located is parallel to the upper end surface of the object to be detected, the first section 11 of the piezoelectric unit 1 is arranged on the side away from the axis of the object to be detected, and the second section 12 of the piezoelectric unit 1 is arranged on the side close to the axis of the object to be detected.

[0047] Among them, the planes where the first section 11 and the second section 12 of the piezoelectric unit 1 are located are coplanar, and the planes where they are located are perpendicular to the central axis of the object to be detected. The first section 11 of the piezoelectric unit 1 is roughly elliptical, and the second section 12 of the piezoelectric unit 1 is roughly triangular, and one side of the triangle is in contact with the long arc side of the ellipse.

[0048] Specifically, the elliptical first section 11 and the roughly triangular second section 12 are combined to form an irregularly shaped piezoelectric unit 1, and the first section 11 of the piezoelectric unit 1 is located on the side of the second section 12 away from the central axis of the object to be detected, the long axis of the first section 11 is perpendicular to the angular bisector of the second section 12, and the tip of the second section 12 is arranged away from the first section 11. This piezoelectric unit 1 with a special shape can be non-uniformly excited and form an eccentric fan-shaped ultrasonic sound field, emitting two-directional main beams toward the object to be detected, and reliably detecting the internal defects of the object to be detected through the ultrasonic beams in two directions, thereby improving the accuracy of the detection. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, reducing the intensity of manual labor, shortening the detection period, improving the availability of the equipment, further improving the work efficiency, and being able to detect the object to be detected at any time, thereby reducing the accident rate.

[0049] The tip of the second section 12 of the piezoelectric unit 1 is arranged toward the central axis of the object to be detected.

[0050] Among them, as one embodiment, the second segment 12 of the piezoelectric unit 1 is roughly an isosceles triangle, and the base of the second segment 12 contacts the side corresponding to the long axis of the first segment 11. As another embodiment, the second segment 12 of the piezoelectric unit 1 is roughly an equilateral triangle, and any side of the second segment 12 can contact the side corresponding to the long axis of the first segment 11.

[0051] The angular bisector of the second segment 12 is perpendicular to the long axis of the first segment 11 , and the angular bisector of the second segment 12 is collinear with the short axis of the first segment 11 .

[0052] Specifically, the elliptical first segment 11 and the roughly triangular second segment 12 are combined to form an irregularly shaped piezoelectric unit 1, and the tip of the second segment 12 of the piezoelectric unit 1 is arranged toward the central axis of the object to be detected. This piezoelectric unit 1 with a special shape can be non-uniformly excited to form an eccentric fan-shaped ultrasonic sound field, and emits main beams in two directions toward the object to be detected. The internal defects of the object to be detected can be reliably detected through the ultrasonic beams in two directions, thereby improving the accuracy of detection.

[0053] The tip angle of the second section 12 of the piezoelectric unit 1 is b, 40°≤b≤60°; the major axis length of the ellipse of the first section 11 of the piezoelectric unit 1 is L1, the minor axis length is L2, and the ratio of the major axis length L1 to the minor axis length L2 is (2.4~2.6):1; the length of the junction between the first section 11 and the second section 12 of the piezoelectric unit 1 is L3, 22mm≤L3≤33mm; the maximum length of the first section 11 and the second section 12 of the piezoelectric unit 1 in the arrangement direction is L4, 28mm≤L4≤42mm; the thickness of the piezoelectric unit 1 is L5, 90μm≤L5≤110μm.

[0054] The angle of the tip of the second section of the piezoelectric unit 1 is b. In the embodiment of the present application, the angle b of the tip of the second section of the piezoelectric unit 1 is preferably 50°.

[0055] Among them, the first section 11 of the piezoelectric unit 1 is roughly elliptical, the major axis length of the ellipse is L1, and the minor axis length of the ellipse is L2. In the embodiment of the present application, the ratio of the major axis L1 to the minor axis L2 of the ellipse of the first section 11 is preferably 2.5:1.

[0056] The length of the connection between the first section 11 and the second section 12 of the piezoelectric unit 1 is the length of the intersection of the side corresponding to the long axis of the first section 11 and the bottom side of the second section 12, which is L3. In the embodiment of the present application, L3 is preferably 27.5 mm.

[0057] The length of the first section 11 and the second section 12 of the piezoelectric unit 1 in the arrangement direction is the sum of the short axis of the first section 11 and the height of the second section 12 of the piezoelectric unit 1, and the maximum sum of the lengths is L4. In the embodiment of the present application, L4 is preferably 35 mm.

[0058] The thickness of the piezoelectric unit is L5. In the embodiment of the present application, the thickness L5 of the piezoelectric unit is preferably 100 μm.

[0059] Specifically, the ultrasonic sound field emitted by the piezoelectric unit 1 can be approximately regarded as all piezoelectric microcrystals, as the result of the interference of multiple emitting sound sources. By designing the shape of the piezoelectric unit 1, the shape and direction of the ultrasonic sound field can be changed. The length L3 at the connection between the first section 11 and the second section 12 of the piezoelectric unit 1 is less than the maximum length L4 of the first section 11 and the second section 12 of the piezoelectric unit 1 in the arrangement direction, so that the piezoelectric unit 1 forms an irregular special shape. Through this special structure, the piezoelectric unit 1 can be non-uniformly excited and form an eccentric fan-shaped ultrasonic sound field, emitting main beams in two directions toward the object to be detected. The internal defects of the object to be detected can be reliably detected through the ultrasonic beams in two directions, thereby improving the accuracy of the detection. It can further realize the detection of the object to be detected without disassembling and dismantling the equipment, reducing the intensity of manual labor, shortening the detection period, and improving the availability of the equipment.

[0060] A plurality of piezoelectric units 1 are provided, and the plurality of piezoelectric units 1 are evenly arranged along the circumferential direction of the central axis of the object to be detected.

[0061] Among them, multiple piezoelectric units 1 can be provided, and the multiple piezoelectric units 1 have the same shape and structure. The planes where the multiple piezoelectric units 1 are located are located in the same plane. The multiple piezoelectric units 1 can be evenly arranged along the circumference of the central axis of the object to be detected.

[0062] Specifically, by evenly arranging a plurality of piezoelectric units 1 along the circumferential direction of the central axis of the object to be detected, it is possible to simultaneously emit a plurality of beams in the first direction and the second direction toward the object to be detected. Under the action of the beams in the first direction and the second direction, the internal defects of the object to be detected can be fully detected, thereby avoiding missing defects inside the object to be detected and improving the accuracy of the detection results of the ultrasonic sensor.

[0063] Four piezoelectric units 1 are provided, and the four piezoelectric units 1 are symmetrically arranged along the circumferential direction of the central axis of the object to be detected.

[0064] Among them, in the embodiment of the present application, four piezoelectric units 1 are provided, and the four piezoelectric units 1 have the same shape and structure. Four piezoelectric units 1 have the best detection effect and are the maximum number that can be placed in the circumferential direction of the center axis of the object to be detected.

[0065] Among them, the four piezoelectric units 1 can be arranged in an array with the central axis of the object to be detected as the center of the circle, and two adjacent piezoelectric units 1 can be obtained by rotating one of the piezoelectric units 1 by 90°, and the two opposite piezoelectric units 1 are symmetrically arranged.

[0066] Specifically, the ultrasonic sound field emitted by the piezoelectric unit 1 can be approximately regarded as all piezoelectric microcrystals, which are the result of the interference of multiple emitting sound sources. By designing the shape of the piezoelectric unit 1, the shape and direction of the ultrasonic sound field can be changed. The four piezoelectric units 1 are roughly petal-shaped. Through this special shape, the piezoelectric unit 1 can be non-uniformly excited to form an eccentric fan-shaped ultrasonic sound field, and the main beams in two directions are emitted toward the object to be detected. The internal defects of the object to be detected can be reliably detected through the ultrasonic beams in two directions, thereby improving the accuracy of the detection. It can further realize the detection of the object to be detected without disassembling and dismantling the equipment, reducing the intensity of manual labor, shortening the detection period, and improving the availability of the equipment.

[0067] The ultrasonic sensor further includes a damping block 2 , which is disposed on a side of the piezoelectric unit 1 away from the object to be detected, and the damping block 2 is connected to the piezoelectric unit 1 .

[0068] Among them, the damping block 2 can be cylindrical. In the embodiment of the present application, the damping block 2 can be made of epoxy resin material, and the surface of the damping block 2 is brushed with tungsten powder.

[0069] Specifically, the damping block 2 can be set on the upper part of the piezoelectric unit 1 and contact the piezoelectric unit 1. The damping block 2 can absorb the ultrasonic wave radiated back from the piezoelectric unit 1 and increase the damping of the vibration of the piezoelectric unit 1, thereby improving the signal-to-noise ratio and resolution of the ultrasonic sensor, further improving the transmitting power and receiving sensitivity of the ultrasonic sensor, and facilitating digital processing of the received signal.

[0070] The ultrasonic sensor further includes a housing 3 , a signal transmitting unit 4 and a signal receiving unit 5 . The signal transmitting unit 4 and the signal receiving unit 5 are electrically connected to the piezoelectric unit 1 , and the signal transmitting unit 4 and the signal receiving unit 5 are disposed inside the housing 3 .

[0071] Among them, the shell 3 can be made of metal material, the piezoelectric unit 1 is arranged in the shell 3, the piezoelectric unit 1 is arranged at the bottom of the shell 3 and fits with the inner wall of the shell 3, the shell 3 provides an installation position for the piezoelectric unit 1, and the shell 3 is used to protect and support the electrical components inside the sensor.

[0072] Among them, a signal transmitting unit 4 and a signal receiving unit 5 are also provided in the shell 3. The signal transmitting unit 4 and the signal receiving unit 5 share a set of leads. The signal transmitting unit 4 is connected to the first surface of the piezoelectric unit 1 and is used to transmit the electric pulse signal to the piezoelectric unit 1 through the leads. The signal receiving unit 5 is connected to the second surface of the piezoelectric unit 1 and is used to receive the information acquired by the piezoelectric unit 1.

[0073] The first surface of the piezoelectric unit 1 is arranged opposite to the second surface of the piezoelectric unit 1 .

[0074] The housing 3 is fixedly connected to the upper part of the object to be detected, and the connection method may be bolt connection or riveting, etc. The connection method is not further limited in this application, and the bottom of the housing 3 fits with the upper end surface of the object to be detected.

[0075] A lead connector group is provided on the upper part of the housing 3, and the signal transmitting unit 4 and the signal receiving unit 5 are connected to the signal processing device through the lead connector group.

[0076] Specifically, the shell 3 provides a stable installation position for the piezoelectric unit 1, and the piezoelectric unit 1 is fixed on the upper end surface of the object to be detected through the shell 3, thereby improving the transmission power and receiving sensitivity of the piezoelectric unit 1. By setting the signal transmitting unit 4 and the signal receiving unit 5 to provide the piezoelectric unit 1 with an electric pulse signal, and digitally processing the signal received by the piezoelectric unit 1, the sensor can be fixed and continuously work on the upper end surface of the object to be detected. On the basis of high transmission power and receiving sensitivity, the received signal is digitally processed, and the signal-to-noise ratio and resolution of the signal are further improved, so that the detection result is more accurate and the work efficiency is improved.

[0077] Another aspect of the present embodiment provides a fault detection device, comprising any one of the ultrasonic sensors described above.

[0078] An ultrasonic sensor and a fault detection device are provided in an embodiment of the present invention, wherein the ultrasonic sensor is configured such that the first section 11 of the piezoelectric unit 1 is elliptical, and the second section 12 is convex at a sharp angle toward a side away from the first section. By designing the shape of the piezoelectric unit 1, the shape and direction of the ultrasonic sound field can be changed, so that the piezoelectric unit 1 can be non-uniformly excited and form an eccentric fan-shaped ultrasonic sound field, emitting main beams in two directions toward the inside of the object to be detected, the beam in the first direction is used to detect damage defects of a section of the object to be detected close to the ultrasonic sensor, and the beam in the second direction is used to detect damage defects of a section of the object to be detected away from the ultrasonic sensor. The internal defects of the object to be detected can be reliably detected, and the accuracy of the detection is improved. At the same time, the object to be detected can be detected without disassembling and dismantling the equipment, so that the detection operation is simpler and more convenient, the intensity of manual labor is reduced, the detection period is shortened, the availability of the equipment is improved, the work efficiency is further improved, and the object to be detected can be detected at any time, reducing the accident rate.

[0079] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0080] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. An ultrasonic sensor, characterized in that: The ultrasonic sensor is used for detecting an object to be detected, comprising at least one piezoelectric unit (1), the piezoelectric unit (1) being arranged on the axial side of the object to be detected, the piezoelectric unit (1) comprising a first section (11) and a second section (12), the first section (11) being elliptical, the second section (12) and the first section (11) being located in the same plane, the second section (12) being connected to the first section (11) and protruding at a sharp angle toward a side away from the first section (11), so that the piezoelectric unit (1) emits a beam in a first direction to detect a section of the object to be detected close to the ultrasonic sensor, and the piezoelectric unit (1) emits a beam in a second direction to detect a section of the object to be detected away from the ultrasonic sensor.

2. The ultrasonic sensor according to claim 1, characterized in that: The first direction is the axial direction of the object to be detected, and the second direction is a direction facing the outer peripheral wall of the object to be detected and forming an angle a with the first direction, 6°≤a≤12°.

3. The ultrasonic sensor according to claim 2, characterized in that: The first section (11) of the piezoelectric unit (1) is located on a side of the second section (12) away from the central axis of the object to be detected, and the major axis of the ellipse of the first section (11) is perpendicular to the angular bisector of the second section (12).

4. The ultrasonic sensor according to claim 3, characterized in that: The tip of the second section (12) of the piezoelectric unit (1) is arranged toward the central axis of the object to be detected.

5. The ultrasonic sensor according to claim 4, characterized in that: The tip angle of the second section (12) of the piezoelectric unit (1) is b, 40°≤b≤60°; The first section (11) of the piezoelectric unit (1) has an elliptical shape with a major axis length of L1 and a minor axis length of L2, and a ratio of the major axis length L1 to the minor axis length L2 is (2.4-2.6):1; The length of the junction between the first section (11) and the second section (12) of the piezoelectric unit (1) is L3, 22 mm ≤ L3 ≤ 33 mm; The maximum length of the first section (11) and the second section (12) of the piezoelectric unit (1) in the arrangement direction is L4, 28 mm ≤ L4 ≤ 42 mm; The thickness of the piezoelectric unit (1) is L5, 90 µm≤L5≤110 µm.

6. The ultrasonic sensor according to claim 5, characterized in that: A plurality of the piezoelectric units (1) are provided, and the plurality of the piezoelectric units (1) are evenly arranged along the circumferential direction of the central axis of the object to be detected.

7. The ultrasonic sensor according to claim 6, characterized in that: Four piezoelectric units (1) are provided, and the four piezoelectric units (1) are symmetrically arranged along the circumferential direction of the central axis of the object to be detected.

8. The ultrasonic sensor according to claim 7, characterized in that: The ultrasonic sensor further comprises a damping block (2), wherein the damping block (2) is arranged on a side of the piezoelectric unit (1) away from the object to be detected, and the damping block (2) is connected to the piezoelectric unit (1).

9. The ultrasonic sensor according to claim 8, characterized in that: The ultrasonic sensor further comprises a housing (3), a signal transmitting unit (4) and a signal receiving unit (5), wherein the signal transmitting unit (4) and the signal receiving unit (5) are electrically connected to the piezoelectric unit (1), and the signal transmitting unit (4) and the signal receiving unit (5) are arranged inside the housing (3).

10. A fault detection device, characterized in that: The ultrasonic sensor comprises the ultrasonic sensor as claimed in any one of claims 1 to 9.

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