Airplane wheel speed sensor

Abstract

The invention discloses an airplane wheel speed sensor, and particularly relates to the field of airplane brake system accessories. Comprising a shell; the rotating shaft is located in the shell, and the rotating shaft is sequentially sleeved with a first bearing, an impeller, a magnetic conduction assembly and a second bearing; a stator is arranged between the impeller and the shell, teeth with the same number are arranged on the impeller and the stator, and a tooth groove is formed between every two adjacent teeth. The cover plate is located in the shell and located on the side, away from the magnetic conduction assembly, of the second bearing. A groove is formed in the surface of the cover plate, a gasket is arranged in the groove, the width of the groove is larger than the outer diameter of the second bearing, and the depth of the groove is larger than the thickness of the gasket. Based on the structure, inflexible rotation and clamping stagnation caused by dimensional tolerance accumulation during installation of the second bearing can be avoided.

Description

Technical Field

[0001] The present application relates to the field of aircraft brake system accessories, and in particular to an aircraft wheel speed sensor. Background Art

[0002] An aircraft's wheel speed sensor converts the wheel's rotational speed signal into a near-sine wave electrical signal, which is then transmitted to the anti-skid brake system's control box. During landing and roll, the control box interprets and analyzes the received sinusoidal wheel speed signal to apply or release the brakes. Therefore, the accuracy and stability of the wheel speed sensor's conversion of the mechanical wheel speed signal into an electrical signal directly impacts the efficiency of the anti-skid brake system.

[0003] The rotating shaft in an aircraft wheel speed sensor is supported by two bearings. This structure requires a large number of components between the outer ring locating surfaces of the two bearings, leading to a wide cumulative range of component assembly tolerances. As the shaft rotates, axial play and accumulated dimensional tolerances can easily cause friction between the bearing end faces and the bearing cover plate, leading to stiff rotation and resulting in jamming. This can affect the stability and continuity of the wheel speed sensor's output sinusoidal signal. Summary of the Invention

[0004] The main purpose of the present application is to provide an aircraft wheel speed sensor, aiming to solve the problem in the prior art that the rotating shaft of the speed sensor is prone to getting stuck.

[0005] To achieve the above-mentioned objectives, the present application provides an aircraft wheel speed sensor, comprising: a housing; a rotating shaft located in the housing, on which a first bearing, an impeller, a magnetic conductive component, and a second bearing are sequentially sleeved; a stator is arranged between the impeller and the housing, and the impeller and the stator are provided with the same number of teeth, with tooth grooves formed between adjacent teeth; a cover plate is located in the housing and on the side of the second bearing away from the magnetic conductive component; a groove is formed on the surface of the cover plate corresponding to the second bearing; a gasket is provided in the groove, the width of the groove is greater than the outer diameter of the second bearing, and the depth of the groove is greater than the thickness of the gasket; the size and number of the teeth are determined by: establishing a first equation based on the thickness of the teeth, the thickness of the tooth groove, the number of teeth and the outer diameter of the impeller; establishing a second equation based on the thickness of the teeth and the thickness of the tooth groove; and determining the thickness of the teeth, the thickness of the tooth groove and the number of teeth by combining the first equation and the second equation.

[0006] Optionally, the first equation is: the quotient of π and the number of teeth, and the product of the outer diameter of the impeller, is equal to the sum of the thickness of the tooth and the thickness of the tooth groove; the second equation is: the sum of the thickness of the tooth and the thickness of the tooth groove is greater than or equal to twice the thickness of the tooth.

[0007] Optionally, a first cavity, a second cavity, and a third cavity that are connected in sequence are opened in the shell along the first direction, the output end of the rotating shaft is located in the first cavity, the first bearing is located in the second cavity adapted thereto, and the impeller, stator, magnetic conductive component, second bearing, bearing seat and cover plate are all located in the third cavity.

[0008] Optionally, steps are formed at both ends of the rotating shaft, the first bearing is sleeved on one step, and the second bearing is sleeved on the other step; the diameter and thickness of the first bearing are both larger than those of the second bearing.

[0009] Optionally, the method for determining the difference between the depth of the groove and the thickness of the gasket is that the sum of the length of the second cavity in the first direction, the axial dimension of the stator, and the axial dimension of the magnetic conductive component is used as the first dimension; the sum of the axial dimension of the first bearing, the distance between the two steps and the axial dimension of the second bearing is used as the second dimension, and the absolute value of the difference between the first dimension and the second dimension is equal to the difference between the depth of the groove and the thickness of the gasket.

[0010] Optionally, a fourth cavity is further provided in the shell, and the fourth cavity is located between the first cavity and the second cavity. In the second direction, the length of the fourth cavity is greater than the length of the first cavity and less than the length of the second cavity; wherein the second direction is the radial direction of the rotating shaft.

[0011] Optionally, the sensor further includes a bearing seat, which is arranged between the second bearing and the housing, and the thickness of the bearing seat is greater than the thickness of the second bearing.

[0012] Optionally, the cover plate is fixed in the housing by nuts.

[0013] Optionally, the cross-sectional shape of the groove is circular.

[0014] Optionally, the gasket is ring-shaped and made of rubber.

[0015] Compared with the prior art, the present invention has the following advantages: The aircraft wheel speed sensor of the present invention has a groove formed on the surface of a cover plate, wherein the width of the groove is greater than the outer diameter of the second bearing, thereby preventing the second bearing from rotating inflexibly or getting stuck due to accumulated dimensional tolerances during installation. A gasket is disposed in the groove, and the depth of the groove is greater than the thickness of the gasket. A gap is formed between the gasket and the second bearing, thereby eliminating unstable installation or interference of small bearings due to accumulated dimensional tolerances, and simultaneously acting as a buffer when axial play exists between the inner and outer rings of the second bearing. The relationship between the thickness of the teeth, the thickness of the tooth grooves, the number of teeth, and the outer diameter of the impeller is established through a first equation, and is constrained by a second equation. The calculated tooth parameters can ensure the output accuracy stability and processing economy of the wheel speed sensor, thereby facilitating the accurate measurement of wheel speed by an anti-skid brake control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic structural diagram of an aircraft wheel speed sensor for this application; Figure 2 This is a schematic structural diagram of a housing in an aircraft wheel speed sensor of the present application; Figure 3 This is a schematic diagram of the structure of a rotating shaft in an aircraft wheel speed sensor of the present application; Figure 4 This is a schematic diagram of the dimensions of the teeth in an aircraft wheel speed sensor according to the present application.

[0017] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0019] A first embodiment of the present invention provides an aircraft wheel speed sensor, such as Figure 1 As shown, it includes a housing 1, a rotating shaft 2 and a cover plate 3; the rotating shaft 2 is located in the housing 1, and a first bearing 4, an impeller 5, a magnetic conductive component 6, and a second bearing 7 are sequentially sleeved on the rotating shaft 2. The first bearing 4 is located at the output end of the rotating shaft 2, and the diameter and thickness of the first bearing 4 are both larger than the second bearing 7; the cover plate 3 is located in the housing 1 and on the side of the second bearing 7 away from the magnetic conductive component 6; a groove is formed on the surface of the cover plate 3 corresponding to the second bearing; a gasket 8 is disposed in the groove, the width of the groove being larger than the outer diameter of the second bearing 7, and the depth of the groove being larger than the thickness of the gasket 8; Among them, a stator 9 is provided between the impeller 5 and the housing 1. In order to prevent the impeller 5 from getting stuck due to contact with the magnetic conductive component 6 during rotation, the thickness of the impeller 5 must be smaller than the thickness of the stator 9 to ensure the rotation space of the impeller 5. If the thickness of the impeller 5 is significantly different from the thickness of the stator 9, the magnetic flux area between the impeller 5 and the stator 9 will be smaller, resulting in a decrease in the magnetic flux in the magnetic circuit. In order to ensure the rotation space of the impeller 5 and maximize the magnetic flux area, the thickness of the impeller 5 should be 2~3mm smaller than the thickness of the stator 9. Figure 2As shown, the impeller 5 and the stator 9 are provided with the same number of teeth, and tooth slots are formed between adjacent teeth. Generally speaking, the dimensions of the teeth of the rotating shaft 2 and the stator 9 include the tooth top diameter, tooth slot diameter, tooth thickness, tooth slot thickness, and the number of teeth. When the wheel drives the rotor (impeller) to rotate, the alternating relative positions of the tooth tops and tooth slots of the rotor and the stator cause the magnetic flux in the magnetic circuit to change periodically, thereby outputting a voltage signal that is approximately a sinusoidal wave. If the thickness of the teeth is unreasonable, it will lead to uneven distribution of the magnetic field, causing the waveform signal output by the wheel speed sensor to be distorted, thereby affecting the frequency stability and accuracy of the wheel speed signal. Generally speaking, the size difference between the tooth top diameter and the tooth slot diameter is (2 to 3) mm; the tooth thickness is about 0.5 mm. In this embodiment, the size and number of the teeth are specifically determined by the following method, specifically: A first equation is established based on the tooth thickness, tooth groove thickness, number of teeth, and the outer diameter of the impeller 5. A second equation is established based on the tooth thickness and tooth groove thickness. The first and second equations are combined to determine the tooth thickness, tooth groove thickness, and number of teeth. Specifically, the first equation is: the quotient of π and the number of teeth multiplied by the outer diameter of the impeller 5 is equal to the sum of the tooth thickness and the tooth groove thickness, that is, D1×π / n=h1+h2. The second equation is: the sum of the tooth thickness and the tooth groove thickness is greater than or equal to twice the thickness, that is, h1+h2≥2×h1. Where the outer diameter of the rotating shaft 2 is D1, the number of teeth is n, the tooth thickness is h1, and the tooth groove thickness is h2.

[0020] In this embodiment, a groove is formed on the surface of the cover plate 3, and the width of the groove is greater than the outer diameter of the second bearing 7 to prevent the second bearing 7 from being stiff and stuck due to accumulated dimensional tolerances during installation. A gasket 8 is provided in the groove, and the depth of the groove is greater than the thickness of the gasket 8. A gap is formed between the gasket 8 and the second bearing 7, which can eliminate unstable installation or interference of small bearings due to accumulated dimensional tolerances. At the same time, it acts as a buffer when there is axial clearance between the inner and outer rings of the second bearing 7. The relationship between the thickness of the teeth, the thickness of the tooth grooves, the number of teeth, and the outer diameter of the impeller 5 is established through the first equation. That is, the number of teeth should ensure that the teeth are evenly distributed on the outer diameter of the rotating shaft 2, that is, the number of teeth should be divisible by the circumferential angle of 360°. At the same time, the calculated tooth parameters, constrained by the second equation, can ensure the output accuracy and stability of the wheel speed sensor and the economical processing, which helps the anti-skid brake control system to accurately measure the wheel speed.

[0021] Further, such as Figure 3 As shown, a first cavity 101, a second cavity 102, and a third cavity 103 are sequentially connected in the housing 1 along the first direction. The first direction is the axial direction of the rotating shaft 2. The output end of the rotating shaft 2 is located in the first cavity 101, the first bearing 4 is located in the second cavity 102 adapted thereto, and the impeller 5, the stator 9, the magnetic conductive component 6, the second bearing 7, the bearing seat and the cover plate 3 are all located in the third cavity 103. Figure 4 As shown, steps are formed at both ends of the rotating shaft 2, the first bearing 4 is sleeved on one step, and the second bearing 7 is sleeved on the other step. Based on the above structure, the method for determining the difference between the depth of the groove and the thickness of the liner 8 is as follows: The sum of the length H1 of the second cavity 102 in the first direction, the axial dimension H2 of the stator 9, and the axial dimension H3 of the magnetic conductive component 6 is taken as the first dimension, that is, ∑H= H1+ H2+ H3; the sum of the axial dimension L1 of the first bearing 4, the distance L2 between the two steps and the axial dimension L3 of the second bearing 7 is taken as the second dimension, that is, ∑L= L1+ L2+ L3. The absolute value of the difference between the first dimension and the second dimension is equal to the difference between the depth of the groove and the thickness of the liner 8, that is, Δδ=∑H-∑L.

[0022] If Δδ>0, the end face of the second bearing 7 is lower than the end face of the bearing seat after installation, and the second bearing 7 is not interfered with. If Δδ is less than 0, the end face of the second bearing 7 is higher than the end face of the bearing seat after installation, and the second bearing 7 is interfered with. Therefore, to prevent interference after the second bearing 7 is installed, the end face of the gasket 8 should be lower than the end face of the cover plate 3 by |Δδ|, which is the difference between the depth of the cover plate 3 and the thickness of the gasket 8.

[0023] In order to prevent the inner ring of the first bearing 4 from contacting and causing jamming with the housing 1, a fourth cavity 104 is further provided in the housing 1 of this embodiment. The fourth cavity 104 is located between the first cavity 101 and the second cavity 102. In the second direction, the length of the fourth cavity 104 is greater than the length of the first cavity 101 and less than the length of the second cavity 102; wherein the second direction is the radial direction of the rotating shaft 2.

[0024] Furthermore, the sensor also includes a bearing seat 10, which is disposed between the second bearing 7 and the housing 1. The thickness of the bearing seat 10 is greater than that of the second bearing 7. A gap is formed between the second bearing 7 and the magnetic component 6. This gap prevents the outer ring end face of the bearing 7 from contacting and rubbing with the magnetic component 6 during rotation, which can cause rotational inflexibility.

[0025] For example, the cover plate 3 is secured to the housing 1 via a nut 11. The cover plate 3 is a circular, thin-walled structure. Once tightened, the stator 9, magnetic permeable assembly 6, bearing seat 10, and cover plate 3 are sequentially compressed within the third cavity 103 of the housing 1. The shaft 2 is a rotating solid. The cross-section of the groove is circular. The gasket 8 is annular and made of rubber, bonded to the groove of the cover plate 3.

[0026] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An aircraft wheel speed sensor, characterized in that: include: case; A rotating shaft is located in the housing, and a first bearing, an impeller, a magnetic conductive component, and a second bearing are sequentially sleeved on the rotating shaft; A stator is provided between the impeller and the housing, and the impeller and the stator are provided with the same number of teeth, with tooth grooves formed between adjacent teeth; A cover plate is located in the housing and on a side of the second bearing away from the magnetic conductive component; a groove is formed along a surface of the cover plate corresponding to the second bearing; A liner is provided in the groove, the width of the groove is greater than the outer diameter of the second bearing, and the depth of the groove is greater than the thickness of the liner; The size and number of the teeth are determined as follows: The first equation is established based on the thickness of the teeth, the thickness of the tooth grooves, the number of teeth and the outer diameter of the impeller; The second equation is established based on the thickness of the tooth and the thickness of the tooth groove; The thickness of the teeth, the thickness of the tooth grooves and the number of teeth are determined by combining the first and second equations.

2. The aircraft wheel speed sensor according to claim 1, wherein: The first equation is: the product of π and the number of teeth, and the outer diameter of the impeller, is equal to the sum of the thickness of the tooth and the thickness of the tooth groove; The second equation is: the sum of the thickness of the tooth and the thickness of the tooth groove is greater than or equal to twice the thickness of the tooth.

3. The aircraft wheel speed sensor according to claim 1, wherein: A first cavity, a second cavity, and a third cavity that are connected in sequence are opened in the shell along the first direction. The output end of the rotating shaft is located in the first cavity, the first bearing is located in the second cavity adapted thereto, and the impeller, stator, magnetic conductive component, second bearing, bearing seat and cover plate are all located in the third cavity; wherein the first direction is the axial direction of the rotating shaft.

4. The aircraft wheel speed sensor according to claim 3, wherein: Steps are formed at both ends of the rotating shaft, the first bearing is sleeved on one step, and the second bearing is sleeved on the other step; The diameter and thickness of the first bearing are both greater than those of the second bearing.

5. The aircraft wheel speed sensor according to claim 4, wherein: The method for determining the difference between the depth of the groove and the thickness of the liner is as follows: The sum of the length of the second cavity in the first direction, the axial dimension of the stator, and the axial dimension of the magnetic conductive component is used as the first dimension; The sum of the axial dimension of the first bearing, the distance between the two steps and the axial dimension of the second bearing is used as the second dimension. The absolute value of the difference between the first dimension and the second dimension is equal to the difference between the depth of the groove and the thickness of the liner.

6. The aircraft wheel speed sensor according to claim 1, wherein: A fourth cavity is further defined in the shell, and is located between the first cavity and the second cavity. In the second direction, the length of the fourth cavity is greater than that of the first cavity and less than that of the second cavity. Wherein, the second direction is the radial direction of the rotating shaft.

7. The aircraft wheel speed sensor according to claim 1, wherein: The sensor further includes a bearing seat, which is arranged between the second bearing and the housing, and the thickness of the bearing seat is greater than the thickness of the second bearing.

8. The aircraft wheel speed sensor according to claim 1, wherein: The cover plate is fixed in the housing by nuts.

9. The aircraft wheel speed sensor according to claim 1, wherein: The cross-section of the groove is circular.

10. The aircraft wheel speed sensor according to claim 9, wherein: The gasket is in the shape of a ring and is made of rubber.

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