Temperature sensor for measuring temperature of moving end face of bearing
By designing a flexible temperature sensor adapted to the bearing end face, and using flexible circuit technology and non-contact antenna installation, the problem of unstable signal coupling under high-speed rotation of the bearing moving end face was solved, and high-precision temperature measurement was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-10
- Publication Date
- 2026-04-07
AI Technical Summary
Existing temperature sensors are difficult to use for real-time measurement on the moving end face of bearings, especially under high-speed rotation conditions where signal undercoupling and data integrity are poor.
A temperature sensor comprising a circular flexible substrate, an inductor layer, and a capacitor layer is designed and fabricated using flexible circuit technology. The circular substrate is adapted to the curvature of the bearing end face. The inductor layer and the capacitor layer are connected by a conductive metal layer to form an LC resonant circuit. The antenna is non-contactly mounted to ensure stable signal coupling.
It achieves high-sensitivity measurement in the range of -40℃ to 150℃, with an average sensitivity of 13.236kHz/℃, stable signal strength, resonant frequency deviation of less than 0.1% during high-speed rotation, and signal strength fluctuation of less than ±1dB.
Smart Images
Figure CN121804703A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial temperature measurement technology, and more specifically, to a temperature sensor for measuring the temperature of the moving end face of a bearing. Background Technology
[0002] Traditional temperature sensors (such as thermocouples, infrared thermometers, and fiber Bragg gratings) are difficult to mount on the moving end face of a bearing, making in-situ monitoring impossible. Fiber optics are prone to breakage in environments with strong vibrations, thermocouples require lead wire connections, and self-powered sensors cannot meet the demands of high-temperature environments, all of which compromise the long-term reliability of bearing operation. Existing solutions also employ sputtering processes to deposit temperature sensors on the moving end face of the bearing; however, the signal transmission of point-like temperature sensors relies on slip rings with limited lifespan (contact type) or is affected by the degree of alignment between the antenna and the sensor during movement (non-contact type). The frequency of the swept-frequency signal emitted by the antenna cannot keep up with the bearing's rotational speed, resulting in signal undercoupling during high-speed rotation and poor data integrity. Summary of the Invention
[0003] (a) Technical problems to be solved The technical problem to be solved by this invention is that existing technologies are unable to achieve real-time temperature measurement of the moving end face of a bearing under high-speed rotation conditions.
[0004] (II) Technical Solution To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a temperature sensor for measuring the temperature of the moving end face of a bearing, comprising a circular flexible substrate, an inductor layer, a capacitor layer, and a conductive metal layer; the circular flexible substrate has multiple interlayer through-holes, and the width of the circular flexible substrate does not exceed the width of the moving end face of the bearing; the inductor layer is disposed on one side surface of the circular flexible substrate; the capacitor layer is disposed on the other side surface of the circular flexible substrate; one end of the conductive metal layer is electrically connected to the inductor layer, and the other end of the conductive metal layer passes through the interlayer through-holes and is electrically connected to the capacitor layer; wherein the width of both the inductor layer and the capacitor layer does not exceed the width of the circular substrate. The circular flexible substrate, as a sensor carrier, is a flexible structure that can adapt to the curvature of the bearing end face for adhesive bonding, ensuring a tight fit. While the width of the circular flexible substrate does not exceed the width of the moving end face of the bearing, it also ensures full end face coverage, avoiding signal blind spots during high-speed rotation.
[0005] Preferably, the inductor layer is a spiral copper coil. The spiral copper coil structure provides a uniform inductance distribution, enhancing the response sensitivity to temperature changes. The spiral shape of the coil optimizes the magnetic field coupling efficiency, making the resonant frequency change linearly correlated with temperature, thus improving measurement accuracy.
[0006] Preferably, the spiral copper coil is formed by a single copper wire arranged in a spiral shape, and the spacing between two adjacent copper wires is 0.0762 mm.
[0007] Preferably, the annular flexible substrate is made of polyimide. Polyimide (PI) is a substrate material with high temperature resistance (>200℃), flexibility, and insulation, making it suitable for harsh working conditions. Its flexibility ensures that the substrate fits snugly against the bearing end face without cracking, solving the fatigue problem of traditional rigid substrates in vibration environments and extending the sensor's lifespan. The insulating properties of polyimide prevent short circuits between the inductor and capacitor layers, ensuring the electrical safety of the LC circuit.
[0008] Preferably, the capacitor layer comprises a pair of interdigital capacitors.
[0009] Preferably, the inductor layer and the capacitor layer are fabricated using flexible circuit technology.
[0010] Preferably, the inner diameter of the annular flexible substrate is 22 mm, and the outer diameter of the annular flexible substrate is 28.8 mm.
[0011] Preferably, the inductor layer is a spiral copper coil with 9 turns, each turn having a wire width of 0.1 mm and a spacing of 0.3 mm between adjacent turns.
[0012] Preferably, the capacitor layer is an interdigital capacitor, which has 6 pairs of fingers, each finger being 4.4 mm long and 0.1 mm wide.
[0013] Secondly, the present invention also provides a bearing temperature monitoring component, including a bearing, an antenna, and a temperature sensor for measuring the temperature of the moving end face of the bearing. The temperature sensor for measuring the temperature of the moving end face of the bearing is glued to the end face of the bearing, and the antenna is positioned opposite the temperature sensor for measuring the temperature of the moving end face of the bearing and spaced apart.
[0014] (III) Beneficial Effects The above-described technical solution of the present invention has at least the following advantages: (1) The circular flexible substrate is a flexible material. The circular temperature sensor used to measure the temperature of the moving end face of the bearing can be adapted to the curvature design of the moving end face of the bearing, which solves the problem that traditional sensors cannot be installed in place.
[0015] (2) The antenna and sensor used for signal acquisition are non-contact installed. The present invention is designed as a ring shape, covering the entire moving end face of the bearing. During the high-speed rotation of the bearing, the projection of the antenna signal receiving end on the moving end face of the bearing is always within the range of the sensor, thereby avoiding interference from high-speed operating conditions and achieving stable coupling and signal acquisition.
[0016] (3) The present invention has an average sensitivity of 13.236 kHz / ℃ and a minimum signal strength of over -10 dB in a wide temperature range of -40℃ to 150℃. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a cross-sectional structural diagram of a temperature sensor for measuring the temperature of the moving end face of a bearing, provided in an embodiment of the present invention.
[0019] Figure 2 This is a front structural schematic diagram of a temperature sensor for measuring the temperature of the moving end face of a bearing, provided in an embodiment of the present invention.
[0020] Figure 3 This is a schematic diagram of the integrated structure of a temperature sensor for measuring the temperature of the moving end face of a bearing, provided in an embodiment of the present invention.
[0021] Figure 4 This is a schematic diagram of the bearing temperature monitoring component provided in an embodiment of the present invention. Figure 5 This is a chart of test data from a temperature sensor used to measure the temperature of the moving end face of a bearing, provided in an embodiment of the present invention.
[0022] The labels for the attached figures are as follows: 100. Temperature sensor for measuring the temperature of the moving end face of a bearing; 200. Bearing; 300. Antenna; 1. Circular flexible substrate; 2. Inductor layer; 3. Capacitor layer. Detailed Implementation
[0023] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0024] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.
[0025] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.
[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments: like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment of the invention provides a temperature sensor 100 for measuring the temperature of the moving end face of a bearing, comprising an annular flexible substrate 1, an inductor layer 2, a capacitor layer 3, and a conductive metal layer; the annular flexible substrate 1 has multiple interlayer through-holes, and the width of the annular flexible substrate 1 does not exceed the width of the moving end face of the bearing; the inductor layer 2 is disposed on one side surface of the annular flexible substrate 1; the capacitor layer 3 is disposed on the other side surface of the annular flexible substrate 1; one end of the conductive metal layer is electrically connected to the inductor layer 2, and the other end of the conductive metal layer passes through the interlayer through-holes and is electrically connected to the capacitor layer 3; wherein the width of both the inductor layer 2 and the capacitor layer 3 does not exceed the width of the annular substrate 1. It should be noted that the moving end face of the bearing can be either the inner ring end face or the outer ring end face of the bearing.
[0027] In one embodiment, the inductor layer 2 is a spiral copper coil.
[0028] In one embodiment, the spiral copper coil is formed by a single copper wire arranged in a spiral shape, with a spacing of 0.0762 mm between adjacent copper wires. Existing technologies include sensor fabrication using magnetron sputtering, but the forming accuracy of magnetron sputtering is only 0.1 mm. In contrast, the FPC flexible circuit technology used in this application achieves a forming accuracy of 0.0762 mm, allowing for the arrangement of more spiral copper coil turns within the same width, thereby further enhancing signal strength.
[0029] In one embodiment, the material of the annular flexible substrate 1 is polyimide.
[0030] In one embodiment, capacitor layer 3 includes a pair of interdigitated capacitors.
[0031] In one embodiment, the inductor layer 2 and the capacitor layer 3 are fabricated using a flexible circuit process.
[0032] In one embodiment, the inner diameter of the annular flexible substrate 1 is 22 mm, and the outer diameter of the annular flexible substrate 1 is 28.8 mm.
[0033] In one embodiment, the inductor layer 2 is a spiral copper coil with 9 turns, each turn having a wire width of 0.1 mm and a spacing of 0.3 mm between adjacent turns.
[0034] In one embodiment, capacitor layer 3 is an interdigitated capacitor with six pairs of fingers, each finger being 4.4 mm long and 0.1 mm wide. The inductor layer is a spiral copper coil, and the capacitor layer is also an interdigitated capacitor; the two are connected by a conductive metal layer to form an LC resonant circuit. When the temperature changes, the dielectric constant of the substrate material changes, causing a change in the inductance or capacitance, which in turn changes the resonant frequency. The antenna couples this frequency signal non-contactly to achieve temperature measurement. The widths of both the inductor and capacitor layers do not exceed the width of the substrate, achieving full end-face coverage and ensuring signal uniformity and full-end-face sensitivity.
[0035] like Figure 4 As shown, this embodiment of the invention also provides a bearing temperature monitoring component, including a bearing 200, an antenna 300, and a temperature sensor 100 for measuring the temperature of the moving end face of the bearing. The temperature sensor for measuring the temperature of the moving end face of the bearing is glued to the end face of the bearing, and the antenna is positioned opposite the temperature sensor for measuring the temperature of the moving end face of the bearing and spaced apart. The diameter of the antenna 300 is greater than or equal to the outer diameter of the temperature sensor 100 for measuring the temperature of the moving end face of the bearing.
[0036] The following are specific embodiments provided in this application: The dimensions of the annular flexible substrate 1 are designed to match the dimensions of the inner ring end face of the 6204 bearing (inner diameter Φ22mm, outer diameter Φ28.8mm), that is, the inner diameter of the annular flexible substrate 1 is designed to be 22mm, and the outer diameter of the annular flexible substrate 1 is designed to be 28.8mm. The annular flexible substrate 1 uses a polyimide film (PI film, thickness 0.11mm), which has high temperature resistance (>200℃) and flexibility. The inductor layer 2 is a spiral copper coil (the outer diameter of the spiral copper coil is 28.0mm, with a total of 9 turns, and its line width / spacing = 0.1mm / 0.3mm). The capacitor layer 3 is an interdigital capacitor (its finger length is 4.4mm, the interdigital capacitor has a total of 6 pairs of fingers, and its width / spacing = 0.1mm / 0.1mm). The electrical connection between the inductor layer 2 and the capacitor layer 3 is achieved through interlayer vias, forming an LC resonant circuit.
[0037] The specific preparation steps are as follows: To facilitate mounting on the inner ring of the bearing while ensuring high reliability and stable electrical performance of the sensor, the temperature sensor 100 for measuring the temperature of the moving end face of the bearing is fabricated using FPC flexible circuit technology. First, the polyimide film material is pretreated, then cut to the designed dimensions to obtain a circular flexible substrate 1. Next, interlayer vias are formed through drilling. Then, a conductive metal layer (preferably a conductive copper layer) is deposited on the via walls using copper plating and electroplating processes to achieve electrical interconnection between the inductor layer 2 and the capacitor layer 3. Subsequently, through processes such as laminating an outer dry film, exposure, and development, the sensing pattern is transferred to a copper foil. Excess copper is then removed through etching to form a precision circuit. After the circuit is fabricated, a cover film is laminated and pressed to provide insulation protection. At this point, the sensor base carrier is complete. The sensor is then cut to its circular shape, removing excess substrate material, and adhered to the inner ring end face of the 6204 bearing using high-low temperature adhesive. The completed flexible sensor and the bearing with the sensor attached, as shown in the image. Figure 3 As shown.
[0038] The bearing, equipped with a temperature sensor 100 for measuring the temperature of its moving end face, is placed in a constant temperature chamber, maintaining a 2mm gap between the temperature sensor 100 and the antenna 300. The temperature range is set from -40℃ to 150℃, with gradients in 10℃ increments. Ten sets of resonant frequency and intensity data are collected at each gradient and averaged. All data are then plotted on the same graph, and the corresponding test data are shown below. Figure 5 As shown in the figure, within this temperature range, the resonant bandwidth is approximately between 31.6 MHz and 34.3 MHz, and the calculated average sensitivity is approximately 13.236 kHz / ℃. When the temperature is gradually increased from -40℃ to 150℃, the resonant frequency shows a gradual decreasing trend. The bearing was then mounted on a rotating fixture for high-speed rotation verification, with the rotation speed increased from 0 rad / min in 100 rad / min increments to 3000 rad / min, with the antenna directly facing the inner ring end face of the bearing. Results: The resonant frequency offset was <0.1%, and the signal strength fluctuation was <±1 dB, proving that the rotation speed does not affect the temperature measurement performance.
[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A temperature sensor for measuring the temperature of the moving end face of a bearing, characterized in that, include: A circular flexible substrate, wherein the circular flexible substrate has multiple interlayer through holes, and the width of the circular flexible substrate does not exceed the width of the bearing moving end face; An inductor layer is disposed on one side surface of the annular flexible substrate; A capacitor layer is disposed on the other side surface of the annular flexible substrate; A conductive metal layer, one end of which is electrically connected to the inductor layer, and the other end of which passes through the interlayer via and is electrically connected to the capacitor layer; The widths of both the inductor layer and the capacitor layer do not exceed the width of the annular substrate.
2. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 1, characterized in that, The inductor layer is a spiral copper coil.
3. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 2, characterized in that, The spiral copper coil is formed by a single copper wire arranged in a spiral shape, with a spacing of 0.0762 mm between two adjacent copper wires.
4. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 1, characterized in that, The material of the annular flexible matrix is polyimide.
5. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 1, characterized in that, The capacitor layer comprises a pair of interdigital capacitors.
6. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 1, characterized in that, The inductor layer and the capacitor layer are fabricated using flexible circuit technology.
7. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 1, characterized in that, The inner diameter of the annular flexible substrate is 22 mm, and the outer diameter of the annular flexible substrate is 28.8 mm.
8. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 7, characterized in that, The inductor layer is a spiral copper coil with 9 turns, each turn having a wire width of 0.1 mm and a spacing of 0.3 mm between adjacent turns.
9. The temperature sensor for measuring the temperature of the moving end face of a bearing as described in claim 8, characterized in that, The capacitor layer is an interdigital capacitor, which has 6 pairs of fingers, each finger being 4.4 mm long and 0.1 mm wide.
10. A bearing temperature monitoring component, characterized in that, The device includes a bearing, an antenna, and a temperature sensor for measuring the temperature of the moving end face of the bearing as described in any one of claims 1-9, wherein the temperature sensor for measuring the temperature of the moving end face of the bearing is glued to the end face of the bearing, and the antenna is positioned opposite the temperature sensor for measuring the temperature of the moving end face of the bearing and spaced apart from it.