A wheel speed sensor

Abstract

The present invention provides a wheel speed sensor, which includes: a Hall element and a signal processing circuit board, the signal processing circuit board includes: a Hall element detection circuit connected to the Hall element, a comparison output circuit and a trigger selection circuit connected to the Hall element detection circuit, and a stable voltage signal circuit and a switch chip; wherein the stable voltage signal circuit and the comparison output circuit are connected to the input end of the switch chip; the output end of the trigger selection circuit is connected to the control end of the switch chip; when the switch chip detects a square wave in the trigger selection circuit, the comparison output circuit is controlled to be connected to the output end of the switch chip; when the square wave is not detected, the stable voltage signal circuit is controlled to be connected to the output end of the switch chip. The beneficial effect of the present invention is that it can automatically identify whether the test wheel is in motion, and the sensor outputs a stable voltage signal when the test senses that the test wheel is not in motion, thereby improving the accuracy of the wheel speed measurement.

Description

Technical Field

[0001] The invention relates to the technical field of rail transportation, and in particular to a wheel speed sensor. Background Art

[0002] The speed sensor is a non-contact speed sensor commonly used in electric locomotives. On rail vehicles, the stability of the vehicle system depends largely on the reliability and accuracy of the speed signal it collects, and the collected speed signal includes the current speed value and the speed change. The collection of speed signals is involved in the traction control, wheel slip protection and train control of the locomotive. Among them, the output signal of the Hall type wheel speed sensor is a square wave. When the test wheel of the wheel speed sensor stops, the high and low levels of its output signal are uncertain, which can easily cause the collection system to misjudge the action and cause vehicle accidents. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a wheel speed sensor.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention provides a wheel speed sensor, which includes: a Hall element, and a signal processing circuit board, wherein the signal processing circuit board includes: a Hall element detection circuit connected to the Hall element, a comparison output circuit connected to the Hall element detection circuit, and a stable voltage signal circuit, a switch chip and a trigger selection circuit; wherein the stable voltage signal circuit and the comparison output circuit are connected to the input end of the switch chip; the input end of the trigger selection circuit is connected to the Hall element detection circuit, and the output end of the trigger selection circuit is connected to the control end of the switch chip; wherein,

[0006] The trigger selection circuit is used to detect whether the Hall element detection circuit outputs a square wave; when the trigger selection circuit detects a square wave, the switch chip controls the comparison output circuit to be connected to the output end of the switch chip; when no square wave is detected, the stable voltage signal circuit is controlled to be connected to the output end of the switch chip.

[0007] Preferably, it also includes a filter output circuit connected to the output end of the switch chip.

[0008] Preferably, the switch chip is a single-pole double-throw switch chip.

[0009] Preferably, the comparison output circuit is a rail-to-rail output circuit.

[0010] Preferably, it further comprises a sensor housing, wherein the Hall device and the signal processing circuit board are arranged in the sensor housing.

[0011] Preferably, the trigger selection circuit is a dual-channel repeatedly triggerable monostable chip.

[0012] The beneficial effects of the present invention are that it can automatically identify whether the test wheel is in motion, and enable the sensor to output a stable voltage signal when the test wheel senses that the test wheel is not in motion, thereby improving the accuracy of wheel speed measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the structure of a wheel speed sensor provided by an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of the circuit structure of a wheel speed sensor provided by an embodiment of the present invention;

[0015] Figure 3 is a circuit diagram of a trigger selection circuit provided by an embodiment of the present invention;

[0016] Figure 4 is a functional diagram of a switch chip of a wheel speed sensor provided by an embodiment of the present invention;

[0017] Figure 5 It is a waveform diagram of the trigger circuit provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0018] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0019] In the description of the present invention, 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", "axial", "radial", "circumferential" 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 limiting the present invention.

[0020] 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.

[0021] In the present invention, 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, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between 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.

[0022] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "towards" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0023] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0024] See also Figure 1 and Figure 2 , Figure 1 is a structural schematic diagram of a wheel speed sensor provided by the present invention, Figure 2 The figure is a schematic diagram of the circuit structure of a wheel speed sensor provided by an embodiment of the present invention.

[0025] An embodiment of the present invention provides a wheel speed sensor, which includes: a Hall element 13, and a signal processing circuit board 14, wherein the signal processing circuit board 14 includes: a Hall element detection circuit 21 connected to the Hall element 13, a comparison output circuit 26 connected to the Hall element detection circuit 21, and a stable voltage signal circuit 27, a switch chip 23 and a trigger selection circuit 22; wherein the stable voltage signal circuit and the comparison output circuit 26 are connected to the input end of the switch chip 23; the input end of the trigger selection circuit 22 is connected to the Hall element detection circuit 21, and the output end of the trigger selection circuit 22 is connected to the control end of the switch chip 23; wherein,

[0026] The trigger selection circuit 22 is used to detect whether the Hall element detection circuit 21 outputs a square wave; when the trigger selection circuit 22 detects a square wave, the switch chip 23 controls the comparison output circuit 26 to be connected to the output end of the switch chip 23; when no square wave is detected, the stable voltage signal circuit 27 is controlled to be connected to the output end of the switch chip 23.

[0027] Preferably, it further includes a filter output circuit 24 connected to the output end of the switch chip 23 .

[0028] Preferably, the switch chip 23 is a single-pole double-throw switch chip 23 .

[0029] Preferably, the comparison output circuit 26 is a rail-to-rail output circuit.

[0030] Preferably, the sensor further comprises a sensor housing 12 , in which the Hall device and the signal processing circuit board 14 are arranged.

[0031] Preferably, the trigger selection circuit 22 is a dual-channel repeatedly triggerable monostable chip.

[0032] The signal processing circuit board 14 further includes a Hall device detection circuit 21 , and an input end of the Hall device detection circuit 21 is connected to the Hall element 13 , and an output end of the Hall device detection circuit 21 is respectively connected to the comparison output circuit 26 and the trigger selection circuit 22 .

[0033] In the above embodiment, it is possible to automatically identify whether the test wheel is in motion, and enable the sensor to output a stable voltage signal when the sensor senses that the test wheel is not in motion, thereby improving the accuracy of wheel speed measurement.

[0034] In order to facilitate understanding of a wheel speed sensor provided by an embodiment of the present invention, it is described in detail below in conjunction with a specific embodiment.

[0035] Continue to refer Figure 1The present invention provides a wheel speed sensor for measuring the rotation speed of a locomotive wheel, which is installed at the end of the locomotive wheel shaft and is arranged adjacent to a test wheel disc, such as Figure 1 As shown, the wheel speed sensor includes: a sensor housing 12, a Hall element 13 and a signal processing circuit board 14 arranged in the sensor housing 12, and also includes a transmission cable 15 and a connector plug 16 connected to the signal processing circuit board 14, wherein the sensor housing 12 is a housing made of non-magnetic conductive material, thereby wrapping and shielding the Hall element 13 and the signal processing circuit board 14 as a whole, and the transmission cable 15 is a shielded cable, and the outer layer of the shielded cable is connected to the housing made of non-magnetic conductive material. Thus, the electromagnetic environment of the entire signal is improved and external interference is reduced.

[0036] In specific use, such as Figure 1 As shown in the figure, the wheel speed sensor is installed on the end of the locomotive wheel shaft and is arranged relatively adjacent to the test wheel disc 11. The sensor housing 12 is connected to the base through fixing bolts. The Hall element 13 and the signal processing circuit board 14 are connected with the sensor housing 12. The transmission cable 15 and the connector plug 16 connect the signal processed by the signal processing circuit board 14 to the outside.

[0037] For reference Figure 1 and Figure 2 The signal processing circuit board 14 includes a Hall element detection circuit 21, a trigger selection circuit 22, a switch chip 23, a filter output circuit 24, a power supply processing circuit 25, a comparison output circuit 26 and a stable voltage signal circuit 27. The switch chip 23 is a single-pole double-throw switch chip. When the test wheel 11 rotates, the Hall element detection circuit 21 converts the rotation signal of the test wheel 11 tested by the Hall element 13 into a square wave signal and sends it to the trigger selection circuit 22 and the comparison output circuit 26. The comparison output circuit 26 is a rail-to-rail output circuit. After receiving the square wave signal, the trigger selection circuit 22 outputs a high level signal (default is a low level signal) to the switch chip 23, and connects the SB and D inside the switch chip 23. The comparison output circuit 26 processes the received square wave signal and then normally inputs it to the filter output circuit 24 through the switch chip 23. The output filter output circuit 24 outputs the signal after filtering. When the test wheel stops, the test wheel signal (high level or low level) detected by the Hall element detection circuit 21 is sent to the trigger selection circuit 22 and the comparison output circuit 26. The trigger selection circuit 22 does not receive the square wave trigger signal, and outputs a low level signal to the switch chip 23 after T time. SA and D inside the switch chip 23 are connected. The stable voltage signal output by the stable voltage signal circuit 27 is input to the output filter output circuit 24 through the switch chip 23. The output filter output circuit 24 filters the signal and outputs it. The power supply processing circuit 25 supplies the external power supply to other circuits after filtering and anti-reverse connection processing.

[0038] Further, such as Figure 3 As shown, the trigger selection circuit is a dual-channel retriggered monostable chip, and its function table is as follows Figure 4 As shown. The normal square wave signal is input to the A1 pin of the first monostable through the current limiting resistor R1, and is also input to the B2 pin of the second monostable. The Reset1 pin and Reset2 pin of the two monostable triggers are simultaneously connected to a high level, the B1 pin of the first trigger is connected to a high level, and the A2 pin of the second trigger is connected to a low level. The two monostable triggers Q1 and Q2 are processed by the OR gate circuit composed of D3, D4 and R4.

[0039] Further, such as Figure 5 As shown in the figure, when a square wave signal appears, its rising and falling edges can trigger a monostable to work, so that its Q terminal outputs a high level. The duration of the high level is determined by the circuit composed of D1, R2 and C1 or D2, R3 and C2. The delay time calculation formula is T = 0.2RX × CX. Because the signal input end does not determine the entry order of its rising and falling edges, in order to prevent the final output waveform from being lost, the Q values ​​of the two monostable trigger outputs are processed in an OR manner so that both the rising and falling edge signals can be processed in time.

[0040] The wheel speed sensor comprises: a Hall element and a signal processing circuit board, the signal processing circuit board comprises: a comparison output circuit connected to the Hall element, a stable voltage signal circuit, a switch chip and a trigger selection circuit; wherein the stable voltage signal circuit and the comparison output circuit are connected to the input end of the switch chip; the input end of the trigger selection circuit is connected to the Hall element, and the output end of the trigger selection circuit is connected to the control end of the switch chip; wherein,

[0041] The trigger selection circuit is used to detect whether the Hall element outputs a square wave; when the trigger selection circuit detects a square wave, the switch chip controls the comparison output circuit to be connected to the output end of the switch chip; when the square wave is not detected, the stable voltage signal circuit is controlled to be connected to the output end of the switch chip.

[0042] It can be seen from the above description that the wheel speed sensor can automatically identify whether the test wheel disc is moving, and make the sensor output a stable voltage signal when the test senses that the test wheel disc is not moving, thereby improving the accuracy of the wheel speed measurement.

[0043] The above are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. A wheel speed sensor, characterized in that: include: A Hall element, and a signal processing circuit board, wherein the signal processing circuit board comprises: a Hall element detection circuit connected to the Hall element, a comparison output circuit connected to the Hall element detection circuit, a stable voltage signal circuit, a switch chip and a trigger selection circuit; wherein the stable voltage signal circuit and the comparison output circuit are connected to the input end of the switch chip; the input end of the trigger selection circuit is connected to the Hall element detection circuit, and the output end of the trigger selection circuit is connected to the control end of the switch chip; wherein, The trigger selection circuit is used to detect whether the Hall element detection circuit outputs a square wave; when the trigger selection circuit detects a square wave, the switch chip controls the comparison output circuit to be connected to the output end of the switch chip; when the square wave is not detected, the stable voltage signal circuit is controlled to be connected to the output end of the switch chip; The switch chip is a single-pole double-throw switch chip; The trigger selection circuit is a dual-channel repeatable trigger monostable chip.

2. The wheel speed sensor according to claim 1, characterized in that: It also includes a filter output circuit connected to the output end of the switch chip.

3. The wheel speed sensor according to claim 1, characterized in that: The comparison output circuit is a rail-to-rail output circuit.

4. The wheel speed sensor according to claim 1, characterized in that: It also includes a sensor housing, in which the Hall element and the signal processing circuit board are arranged.

Images