Speed sensor

Abstract

The present invention discloses a speed sensor, comprising: a housing; a speed sensing chip disposed in the housing; and a temperature sensing element disposed in the housing. The temperature sensing element is arranged to be in direct thermal contact with the speed sensing chip or thermally connected to the speed sensing chip through a heat conducting material to accurately detect the temperature of the speed sensing chip. In the present invention, the temperature sensing element can timely and accurately detect the temperature of the speed sensing chip, so that it can monitor in real time and accurately whether the speed sensing chip fails due to too high or too low temperature. The present invention is very convenient to use and has a low cost.

Description

Technical Field

[0001] The present invention relates to a speed sensor, and more particularly to a Hall speed sensor. Background Art

[0002] In the prior art, a Hall speed sensor usually detects the rotational speed according to the high and low level changes generated by the Hall chip sensing the rotation of a gear. The operating temperature range of the Hall chip is usually from -40 degrees Celsius to +125 degrees Celsius. Long-term high-temperature (above +125 degrees Celsius) or low-temperature (below -40 degrees Celsius) environments will affect the lifespan of the Hall speed sensor.

[0003] The Hall speed sensor is a key component in the railway braking system. However, the railway braking system has been operating in a high-temperature environment, which will affect the lifespan of the Hall speed sensor. We need to detect the temperature of the Hall chip itself, so that the failure time of the Hall speed sensor can be judged according to the detected ambient temperature data.

[0004] In the prior art, an additional temperature sensor is usually directly used to detect the external ambient temperature of the Hall speed sensor rather than directly measuring the temperature of the Hall chip itself. Since the Hall speed sensor has a housing and is filled with resin therein, resulting in a significant temperature difference between the external ambient temperature and the temperature of the Hall chip, it cannot be used to accurately judge whether the Hall chip has failed or will fail, resulting in the inability to give an early warning or replace the Hall chip in time. Summary of the Invention

[0005] The object of the present invention aims to solve at least one of the above problems and defects existing in the prior art.

[0006] According to one aspect of the present invention, there is provided a speed sensor, comprising: a housing; a speed sensing chip disposed in the housing; and a temperature sensing element disposed in the housing. The temperature sensing element is arranged to be in direct thermal contact with the speed sensing chip or thermally connected to the speed sensing chip through a heat-conducting material to accurately detect the temperature of the speed sensing chip.

[0007] According to an exemplary embodiment of the present invention, the heat-conducting material is a metallic material.

[0008] According to another exemplary embodiment of the present invention, the heat-conducting material is the copper material on a printed circuit board, and the copper material forms a heat-conducting contact with both the speed sensing chip and the temperature sensing element at the same time to conduct the heat on the speed sensing chip to the temperature sensing element.

[0009] According to another exemplary embodiment of the present invention, the printed circuit board (60) is a flexible printed circuit board disposed in the housing. The flexible printed circuit board has a mounting portion located on top of the speed sensing chip, and the temperature sensing element is mounted on the mounting portion.

[0010] According to another exemplary embodiment of the present invention, the mounting portion of the flexible printed circuit board has a first surface facing the speed sensing chip and a second surface facing away from the speed sensing chip, and the temperature sensing element is mounted on the first surface or the second surface of the mounting portion.

[0011] According to another exemplary embodiment of the present invention, the speed sensor further includes an insulating film attached to the second surface of the mounting portion of the flexible printed circuit board to electrically isolate the flexible printed circuit board from the housing.

[0012] According to another exemplary embodiment of the present invention, the heat-conducting material is disposed on the mounting portion of the flexible printed circuit board for thermally connecting the temperature sensing element and the speed sensing chip.

[0013] According to another exemplary embodiment of the present invention, the heat-conducting coefficient of the heat-conducting material is not less than 100 W / m·K.

[0014] According to another exemplary embodiment of the present invention, the top surface of the speed sensing chip is thermally connected or in thermal contact with the mounting portion of the flexible printed circuit board, and is thermally connected to the temperature sensing element via the heat-conducting material.

[0015] According to another exemplary embodiment of the present invention, the speed sensor further includes an insulating seat mounted in the housing. An installation chamber for mounting the speed sensing chip and a positioning groove for positioning the temperature sensing element are formed on the insulating seat.

[0016] According to another exemplary embodiment of the present invention, the speed sensor includes two speed sensing chips, and the two speed sensing chips are respectively mounted in two installation chambers on the insulating seat; the positioning groove is located between the two installation chambers, such that the temperature sensing element is positioned between the two speed sensing chips and adjacent to the two speed sensing chips.

[0017] According to another exemplary embodiment of the present invention, the speed sensor further includes a circuit board mounted in the housing. The leads of the speed sensing chip are electrically connected to the circuit board, and the temperature sensing element is electrically connected to the circuit board via conductive traces on the flexible printed circuit board.

[0018] According to another exemplary embodiment of the present invention, the speed sensor further includes a connector which is mounted on a port of the housing, and the connector has external terminals that are electrically connected to the circuit board and used for outputting electrical signals.

[0019] According to another exemplary embodiment of the present invention, the speed sensor further includes a sealing gasket which is disposed between the housing and the connector to seal the mating interface between the housing and the connector.

[0020] According to another exemplary embodiment of the present invention, the housing further includes a mounting plate connected to an outer surface of its peripheral wall, and a plurality of mounting holes are formed in the mounting plate, so that the speed sensor can be mounted on a fixing bracket through threaded connectors passing through the mounting holes.

[0021] According to another exemplary embodiment of the present invention, epoxy resin for electrical insulation is filled in the housing to electrically isolate the electronic devices in the housing from the housing.

[0022] According to another exemplary embodiment of the present invention, the speed sensor is a Hall speed sensor, the speed sensing chip is a Hall chip, and the temperature sensing element is a thermistor.

[0023] In the foregoing various exemplary embodiments according to the present invention, the temperature sensing element can detect the temperature of the speed sensing chip in a timely and accurate manner, so as to be able to monitor in real time and accurately whether the speed sensing chip fails due to too high or too low temperature.

[0024] Other objects and advantages of the present invention will become apparent and can help to have a comprehensive understanding of the present invention through the description of the present invention with reference to the accompanying drawings hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A perspective schematic diagram showing a speed sensor according to an exemplary embodiment of the present invention;

[0026] Figure 2 Show Figure 1 An exploded schematic diagram of the shown speed sensor;

[0027] Figure 3 Show Figure 2 A schematic diagram of a circuit board, a flexible printed circuit board and a temperature sensing element of the shown speed sensor;

[0028] Figure 4 Show Figure 2 An assembled schematic diagram of internal electronic devices of the shown speed sensor;

[0029] Figure 5 Display Figure 2 Schematic diagram of the assembly of the temperature sensing element, speed sensing chip and insulating seat of the speed sensor shown;

[0030] Figure 6 Display Figure 2 Exploded view of the temperature sensing element, speed sensing chip and insulating seat of the speed sensor shown. Detailed implementation mode

[0031] The technical solution of the present invention will be further specifically described below through embodiments in conjunction with the drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0032] In addition, in the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments disclosed herein. However, it is obvious that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in diagrammatic form to simplify the drawings.

[0033] According to an overall inventive concept of the present invention, there is provided a speed sensor, comprising: a housing; a speed sensing chip disposed in the housing; and a temperature sensing element disposed in the housing. The temperature sensing element is arranged to be in direct thermal contact with the speed sensing chip or thermally connected to the speed sensing chip through a heat conductive material to accurately detect the temperature of the speed sensing chip.

[0034] Figure 1 Display a three-dimensional schematic diagram of a speed sensor according to an exemplary embodiment of the present invention. Figure 2 Display Figure 1 Exploded view of the speed sensor shown. Figure 3 Display Figure 2 Schematic diagram of the circuit board 30, flexible printed circuit board 60 and temperature sensing element 70 of the speed sensor shown.

[0035] As Figures 1 to 3 shown, in the illustrated embodiment, the speed sensor includes a housing 10, a speed sensing chip 40, a temperature sensing element 70 and an insulating film 80. The housing 10 has a peripheral wall and a top wall 10a. The speed sensing chip 40 is disposed in the housing 10 and close to the top wall 10a of the housing 10. In the illustrated embodiment, the temperature sensing element 70 is disposed in the housing 10 and adjacent to the speed sensing chip 40. Therefore, the temperature sensing element 70 can timely and accurately detect the temperature of the speed sensing chip 40.

[0036] Figure 4 Display Figure 2 Schematic diagram of the internal electronics assembly of the shown speed sensor.

[0037] As Figures 1 to 4 shown, in the illustrated embodiment, the speed sensor further includes a flexible printed circuit (FPC) 60. The flexible printed circuit 60 is disposed in the housing 10 and includes a mounting portion 61 perpendicular to the axis of the housing 10. In the illustrated embodiment, since the flexible printed circuit 60 is flexible, the mounting portion 61 can be made perpendicular to the axis of the housing 10 by bending the flexible printed circuit 60. After assembly, the mounting portion 61 of the flexible printed circuit 60 is located on top of the speed sensing chip 40, and the temperature sensing element 70 is mounted on the mounting portion 61.

[0038] As Figures 1 to 4 shown, in the illustrated embodiment, the mounting portion 61 of the flexible printed circuit 60 has a first surface 61a facing the speed sensing chip 40 and a second surface 61b facing away from the speed sensing chip 40. In the illustrated embodiment, the temperature sensing element 70 is mounted on the first surface 61a of the mounting portion 61 such that the temperature sensing element 70 and the speed sensing chip 40 are on the same side of the mounting portion 61 of the flexible printed circuit 60. However, it should be noted that the present invention is not limited to the illustrated embodiment. For example, the temperature sensing element 70 can also be mounted on the second surface 61b of the mounting portion 61 such that the temperature sensing element 70 and the speed sensing chip 40 are on opposite sides of the mounting portion 61 of the flexible printed circuit 60.

[0039] As Figures 1 to 4 shown, in the illustrated embodiment, the speed sensor further includes an insulating film 80, which is attached to the second surface 61b of the mounting portion 61 of the flexible printed circuit 60. The insulating film 80 is located between the top wall 10a of the housing 10 and the flexible printed circuit 60 and is used to electrically isolate the speed sensing chip 40, the flexible printed circuit 60, and the temperature sensing element 70 from the housing 10. In the illustrated embodiment, the insulating film 80 needs to have good electrical insulation properties. Generally, the insulation strength of the insulating film 80 is not less than 2 kV. For example, the insulation strength of the insulating film 80 can be 2 kV, 3 kV, 4 kV, 5 kV, or higher.

[0040] As Figures 1 to 4As shown, in the illustrated embodiment, a heat-conducting material (not shown) is provided on the mounting portion 61 of the flexible printed circuit board 60. The heat-conducting material is used for thermally connecting the temperature sensing element 70 and the speed sensing chip 40. The heat-conducting material on the mounting portion 61 can improve the heat conduction performance and can transfer heat from the speed sensing chip 40 to the temperature sensing element 70 more quickly. For example, in an exemplary embodiment of the present invention, the heat-conducting material can be a metallic heat-conducting material or a non-metallic heat-conducting material formed on the mounting portion 61, and the heat conduction coefficient of the heat-conducting material is not less than 100 W / m·K. In an exemplary embodiment of the present invention, the heat-conducting material can be the copper material on the flexible printed circuit board 60. For example, a copper heat-conducting pad or a copper heat-conducting layer.

[0041] As Figures 1 to 4 shown, in the illustrated embodiment, the mounting portion 61 of the flexible printed circuit board 60 is disc-shaped, and the other parts of the flexible printed circuit board 60 are strip-shaped. The shape and size of the surface of the disc-shaped mounting portion 61 are the same as or substantially the same as the shape and size of the inner surface of the top wall 10a of the housing 10. Similarly, the shape and size of the surface of the insulating film 80 attached to the mounting portion 61 are also the same as or substantially the same as the shape and size of the inner surface of the top wall 10a of the housing 10.

[0042] As Figures 1 to 4 shown, in the illustrated embodiment, the speed sensor further includes a circuit board 30 mounted in the housing 10. The lead 41 of the speed sensing chip 40 is electrically connected to the circuit board 30, and the temperature sensing element 70 is electrically connected to the circuit board 30 via a conductive trace (not shown) on the flexible printed circuit board 60.

[0043] Figure 5 Show Figure 2 The assembly schematic diagram of the temperature sensing element 70, the speed sensing chip 40 and the insulating seat 50 of the speed sensor shown; Figure 6 Show Figure 2 The exploded schematic diagram of the temperature sensing element 70, the speed sensing chip 40 and the insulating seat 50 of the speed sensor shown.

[0044] As Figures 2 to 6 shown, in the illustrated embodiment, the speed sensor further includes an insulating seat 50 mounted in the housing 10. An installation chamber 51 for installing the speed sensing chip 40 is formed on the insulating seat 50, and the speed sensing chip 40 is installed in the installation chamber 51.

[0045] As Figures 2 to 6 shown, in the illustrated embodiment, the insulating seat 50 is located between the mounting portion 61 of the flexible printed circuit board 60 and one end of the circuit board 30. A positioning groove 52 for positioning the temperature sensing element 70 is formed on the insulating seat 50, and the temperature sensing element 70 is positioned in the positioning groove 52.

[0046] As Figures 2 to 6 shown, in the illustrated embodiment, the speed sensor includes two speed sensing chips 40, and the two speed sensing chips 40 are respectively mounted in two mounting chambers 51 on the insulating seat 50. A positioning groove 52 is located between the two mounting chambers 51, so that the temperature sensing element 70 is positioned between the two speed sensing chips 40. Since the temperature sensing element 70 is positioned adjacent to both of the two speed sensing chips 40, the temperatures of the two speed sensing chips 40 can be detected more accurately and timely.

[0047] As Figures 2 to 6 shown, in the illustrated embodiment, the top surface of the speed sensing chip 40 is thermally connected or in thermal contact with the mounting portion 61 of the flexible printed circuit board 60, and is thermally connected to the temperature sensing element 70 via the heat conductive material on the mounting portion 61.

[0048] As Figure 1 and Figure 2 shown, in the illustrated embodiment, the speed sensor further includes a connector 20. The connector 20 is mounted on the port of the housing 10, and the connector 20 has an external terminal 21 that is electrically connected to the circuit board 30 and is used for outputting an electrical signal.

[0049] As Figure 1 and Figure 2 shown, in the illustrated embodiment, the speed sensor further includes a sealing gasket (not shown). The sealing gasket is disposed between the housing 10 and the connector 20 to seal the mating interface between the housing 10 and the connector 20.

[0050] As Figure 1 and Figure 2 shown, in the illustrated embodiment, the housing 10 further includes a mounting plate 11 connected to the outer surface of its peripheral wall. A plurality of mounting holes 11a are formed in the mounting plate 11, so that the speed sensor can be mounted on a fixing bracket (not shown) through threaded connectors passing through the mounting holes 11a.

[0051] As Figure 1 and Figure 2 shown, in the illustrated embodiment, epoxy resin for electrical insulation is filled in the housing 10 to electrically isolate the electronic devices (such as the circuit board 30, the flexible printed circuit board 60, the speed sensing chip 40, and the temperature sensing element 70, etc.) in the housing 10 from the housing 10.

[0052] As Figure 1 and Figure 2 shown, in the illustrated embodiment, the speed sensor is a dual-channel Hall speed sensor, and the speed sensing chip 40 is a Hall chip. The temperature sensing element 70 can be a thermistor or other suitable temperature detection device.​

[0053] In the foregoing embodiments of the present invention, when the temperature detected by the temperature sensing element 70 is higher than a predetermined high temperature or lower than a predetermined low temperature, it can be determined that the speed sensing chip 40 fails. In this way, the failure time of the speed sensing chip 40 can be determined according to the detected temperature data.

[0054] Those skilled in the art can understand that the above-described embodiments are all exemplary, and those skilled in the art can make improvements thereto. The structures described in various embodiments can be freely combined without conflict in terms of structure or principle, and these changes should reasonably fall within the protection scope of the present invention.

[0055] Although the present invention has been described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to exemplarily illustrate the preferred embodiments of the present invention and should not be construed as a limitation of the present invention.

[0056] Although some embodiments of the general concept of the present invention have been shown and described, those of ordinary skill in the art will understand that changes can be made to these embodiments without departing from the principles and spirit of the general concept of the present invention. The scope of the present invention is defined by the claims and their equivalents.

[0057] It should be noted that the term "comprising" does not exclude other elements or steps, and the terms "a" or "an" do not exclude a plurality. Additionally, any element number in the claims should not be construed as limiting the scope of the present invention.

Claims

1. A speed sensor, characterized in that, Comprising: A housing (10); A speed sensing chip (40), disposed in the housing (10); And A temperature sensing element (70), disposed in the housing (10), The temperature sensing element (70) is thermally connected to the speed sensing chip (40) through a heat conductive material to accurately detect the temperature of the speed sensing chip (40), The speed sensor further includes a printed circuit board (60) disposed in the housing (10), and the heat conductive material is copper on the printed circuit board (60), and the copper simultaneously forms a heat conductive contact with the speed sensing chip (40) and the temperature sensing element (70) to conduct the heat on the speed sensing chip (40) to the temperature sensing element (70), The printed circuit board (60) is a flexible printed circuit board (60) disposed in the housing (10), and the flexible printed circuit board (60) has a mounting portion (61) located on the top of the speed sensing chip (40), and the temperature sensing element (70) is mounted on the mounting portion (61), The mounting portion (61) of the flexible printed circuit board (60) has a first surface (61a) facing the speed sensing chip (40) and a second surface (61b) facing away from the speed sensing chip (40), and the temperature sensing element (70) is mounted on the first surface (61a) or the second surface (61b) of the mounting portion (61), The speed sensor further includes an insulating film (80), and the insulating film (80) is attached to the second surface (61b) of the mounting portion (61) of the flexible printed circuit board (60) to electrically isolate the flexible printed circuit board (60) from the housing (10), The speed sensor further includes an insulating seat (50) mounted in the housing (10), and an installation chamber (51) for mounting the speed sensing chip (40) and a positioning groove (52) for positioning the temperature sensing element (70) are formed on the insulating seat (50), The speed sensor includes two speed sensing chips (40), and the two speed sensing chips (40) are respectively mounted into two installation chambers (51) on the insulating seat (50), and the positioning groove (52) is located between the two installation chambers (51), so that the temperature sensing element (70) is positioned between the two speed sensing chips (40) and adjacent to the two speed sensing chips (40).

2. The speed sensor according to claim 1, wherein: The heat conductive material is disposed on the mounting portion (61) of the flexible printed circuit board (60) for thermally connecting the temperature sensing element (70) and the speed sensing chip (40).

3. The speed sensor according to claim 2, wherein: The heat conductivity coefficient of the heat conductive material is not less than 100 W / m·K.

4. The speed sensor according to claim 2, wherein: The top surface of the speed sensing chip (40) is thermally connected or in thermal contact with the mounting portion (61) of the flexible printed circuit board (60), and is thermally connected to the temperature sensing element (70) via the heat conductive material.

5. The speed sensor according to claim 1, wherein: The speed sensor further includes a circuit board (30) mounted in the housing (10), leads (41) of the speed sensing chip (40) are electrically connected to the circuit board (30), and the temperature sensing element (70) is electrically connected to the circuit board (30) via conductive traces on the flexible printed circuit board (60).

6. The speed sensor according to claim 5, wherein: The speed sensor further includes a connector (20), the connector (20) is mounted on a port of the housing (10), and the connector (20) has external terminals (21) electrically connected to the circuit board (30) for outputting electrical signals.

7. The speed sensor according to claim 6, wherein: The speed sensor further includes a sealing gasket, and the sealing gasket is disposed between the housing (10) and the connector (20) to seal the mating interface between the housing (10) and the connector (20).

8. The speed sensor according to claim 1, wherein: The housing (10) further includes a mounting plate (11) connected to the outer surface of its peripheral wall, and a plurality of mounting holes (11a) are formed in the mounting plate (11), so that the speed sensor can be mounted on a fixing bracket through threaded connectors passing through the mounting holes (11a).

9. The speed sensor according to claim 1, wherein: Epoxy resin for electrical insulation is filled in the housing (10) to electrically isolate the electronic devices in the housing (10) from the housing (10).

10. The speed sensor according to claim 1, wherein: The speed sensor is a Hall speed sensor, the speed sensing chip (40) is a Hall chip, and the temperature sensing element (70) is a thermistor.

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