Hybrid excitation type wheel speed sensor

Abstract

The invention belongs to the technical field of wheel type take-off and landing aircraft anti-skid braking systems, and particularly relates to a hybrid excitation type wheel speed sensor which comprises a shell, a rotor assembly and a stator assembly, the rotor assembly and the stator assembly are contained in the shell, and the stator assembly comprises a stator shaft and at least one group of hybrid excitation assemblies arranged on the stator shaft in a sleeving mode. The hybrid excitation assembly comprises a winding group, a magnetic conductive plate and a permanent magnet fixed on the magnetic conductive plate, the magnetizing direction of the permanent magnet is consistent with the direction of a magnetic field generated after the winding group is electrified, and stator teeth are arranged on the periphery of the magnetic conductive plate; the rotor assembly comprises a rotor shaft and a rotor yoke fixed on the rotor shaft. The inner ring of the rotor yoke is provided with rotor teeth opposite to the stator teeth. According to the wheel speed sensor, the permanent magnet is fixedly arranged on the magnetic conductive plate, so that the permanent magnet and the winding group jointly serve as a magnetic source, the requirement for low output voltage, high rotating speed and high amplitude of the wheel speed sensor under the condition that exciting current is limited is met, meanwhile, the size of the wheel speed sensor is smaller, and the requirement for the limited size is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of anti-skid brake systems of wheeled vertical take-off and landing aircrafts, and particularly relates to a composite excitation type wheel speed sensor. BACKGROUND

[0002] Wheeled aircrafts, covering from large fixed-wing transporters, commercial passenger aircrafts to rotary-wing helicopters, rely on efficient and reliable brake systems to achieve safe deceleration and stopping during landing and ground running stages. For high-speed landing fixed-wing aircrafts, the brake system is one of the decisive factors to ensure landing safety, shorten the sliding distance and improve runway utilization. For helicopters, the sliding and braking on the wheeled landing gear also require precise anti-skid control. The anti-skid brake system is a key subsystem to ensure the brake efficiency and directional stability of the above-mentioned aircrafts, and the wheel speed sensor, as the speed feedback source of the system, detects the angular velocity of the wheel and generates an alternating signal frequency proportional to it, providing an input signal for the anti-skid brake system.

[0003] The wheel speed sensor applied to the prior art aircraft mainly adopts an electromagnetic excitation type design, and its working principle is based on electromagnetic induction effect. Such a sensor usually includes a shell, a rotor assembly and a stator assembly. The stator assembly is composed of a stator shaft and a winding set sleeved on the stator shaft, and the winding set generates an alternating magnetic field after being powered. The rotor assembly includes a rotor shaft and a rotor yoke, and the rotor yoke is provided with rotor teeth. When the rotor shaft rotates, the magnetic resistance between the rotor teeth and the stator teeth changes periodically, thereby inducing an electric signal in the winding set to realize wheel speed detection.

[0004] However, the pure electromagnetic excitation sensor has some inherent defects. First, since only the winding set is powered to generate a magnetic field, in order to obtain sufficient magnetic field strength, a larger winding set and a higher excitation current are often required, resulting in a bulky sensor structure, which is difficult to apply in limited installation space. Second, the electromagnetic excitation method has high power consumption, and the magnetic field strength is easily affected by current fluctuations, which is insufficient in stability. In addition, under high-speed rotation conditions, the response speed and signal-to-noise ratio of the electromagnetic excitation type sensor may decrease, affecting the measurement accuracy. Therefore, the existing electromagnetic excitation type wheel speed sensor faces challenges in miniaturization and high performance, and a new design is urgently needed to reduce the space occupation and improve the performance. SUMMARY

[0005] To solve the above technical problems, the application provides a composite excitation type wheel speed sensor, which uses a permanent magnet and a coil as a magnetic source together. By changing the size of the excitation current, the output voltage amplitude is improved, the demand for low speed and high amplitude of the wheel speed sensor output voltage under the condition of limited excitation current is met, and the volume of the wheel speed sensor is smaller, meeting the demand of limited volume.

[0006] The application adopts the following technical solutions:

[0007] A composite excitation wheel speed sensor includes a housing, and a stator assembly and a rotor assembly housed within the housing;

[0008] The stator assembly includes a stator shaft, a stator end cover fixed to one end of the stator shaft, and at least one set of composite excitation components sleeved on the stator shaft. The stator shaft is fixed inside the housing. The composite excitation component includes a winding assembly, a magnetic guide plate, and a permanent magnet fixed on the magnetic guide plate. The magnetization direction of the permanent magnet is consistent with the direction of the magnetic field generated after the winding assembly is energized. Stator teeth are provided on the outer periphery of the magnetic guide plate.

[0009] The rotor assembly includes a rotor shaft, a rotor end cover fixed to one end of the rotor shaft, and a rotor yoke fixed to the rotor end cover. The rotor shaft and the stator shaft are axially spaced and coaxially arranged. The rotor shaft is rotatably mounted on the housing and one end of it extends out of the housing. The ends of the rotor shaft and the stator shaft opposite to each other are rotatably connected by a first bearing. The inner ring of the first bearing is connected to the rotor shaft, and the outer ring is supported on the stator shaft by a bearing seat.

[0010] The stator end cover and the rotor end cover form a magnetic circuit space. The composite excitation assembly is installed sequentially in the magnetic circuit space along the axial direction. The inner ring of the rotor yoke is provided with rotor teeth that are opposite to the stator teeth, so that when the rotor shaft rotates, the magnetic resistance between the rotor teeth and the stator teeth changes periodically.

[0011] Furthermore, a set of composite excitation components is provided in the magnetic circuit space; the magnetic guide plate and the stator end cover are respectively located on both sides of the axial direction of the winding group, and the end of the magnetic guide plate facing away from the winding group abuts against the bearing seat; the winding group includes a winding bracket and a winding, the winding bracket is sleeved on the stator shaft, and a winding groove is formed on the outer side of the winding bracket, and the winding is set in the winding groove.

[0012] Furthermore, two sets of composite excitation components are fitted on the stator shaft, and the two sets of composite excitation components are isolated by a magnetic shielding plate; one set of composite excitation components is located between the stator end cover and the magnetic shielding plate, and the other set of composite excitation components is located between the magnetic shielding plate and the bearing housing;

[0013] Two magnetic plates abut against the axial end faces of the magnetic shielding plate respectively. One winding group is located between the magnetic plate and the stator end cover, and the other winding group is located between the magnetic plate and the bearing seat. The winding group includes a winding bracket and a winding. The winding bracket is sleeved on the stator shaft, and a winding groove is formed on the outer side of the winding bracket. The winding is set in the winding groove.

[0014] Furthermore, the magnetic guide plate includes a disc-shaped portion fitted on the stator shaft and a cylindrical portion extending axially from the outer periphery of the disc-shaped portion. At least a portion of the cylindrical portion surrounds the winding assembly, and stator teeth are provided on the outer periphery of the cylindrical portion. The permanent magnet is disposed on the disc-shaped portion at one end opposite to the winding assembly.

[0015] Furthermore, an annular groove is provided on one end face of the disc-shaped part facing the winding assembly, and the permanent magnet has an annular structure and is embedded in the annular groove.

[0016] Furthermore, at least three sets of composite excitation components are sleeved on the stator shaft. The at least three sets of composite excitation components are isolated from each other by magnetic shielding plates. The two sets of composite excitation components located on both sides of the axial direction have the same structure, and the remaining composite excitation components have the same structure.

[0017] The outer wall of the magnetic guide plate of the composite excitation assembly located in the middle has an annular groove. The permanent magnet is embedded in the opposite side walls of the annular groove, and the winding assembly is located in the annular groove. The outer wall of the magnetic guide plate is provided with stator teeth that cooperate with the rotor teeth.

[0018] Furthermore, a stator pressure plate is provided on the side of the stator end cover facing away from the winding assembly. The stator pressure plate is connected to the housing through a threaded structure to press the stator assembly into the housing.

[0019] Furthermore, the rotor assembly and stator assembly are sealed inside the housing by a rear cover and an oil seal at both ends, respectively.

[0020] The oil seal is fitted onto the rotor shaft, and its outer ring is sealed to the housing.

[0021] The end of the housing away from the rotor shaft is provided with a mounting stop, and the rear cover is installed on the housing through the mounting stop.

[0022] Furthermore, the composite excitation wheel speed sensor is cylindrical in shape, with a diameter of 30mm to 35mm and a height of 28mm to 32mm.

[0023] Furthermore, the stator end cover, rotor yoke, magnetic guide plate, and stator shaft form a first magnetic circuit space, in which a set of windings is located within the first magnetic circuit space;

[0024] The rotor end cover, bearing housing, rotor yoke, magnetic guide plate, and stator shaft form a second magnetic circuit space. Another set of windings is located in the second magnetic circuit space, and the volume of the second magnetic circuit space is greater than the volume of the first magnetic circuit space.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The composite excitation wheel speed sensor of this application uses a permanent magnet fixed on a magnetic plate, so that the permanent magnet and the winding group together serve as a magnetic source. The magnetization direction of the permanent magnet is consistent with the direction of the magnetic field generated after the winding group is energized, which constitutes the core of composite excitation. The permanent magnet provides a stable magnetic field that does not require external energy to maintain. The magnetic field generated after the winding group is energized is superimposed on it, realizing the superposition and enhancement effect of the magnetic field. This allows the sensor to obtain a stronger effective working magnetic field under the same volume, or to significantly reduce the excitation current under the same output signal requirements, thereby directly reducing the power consumption of the sensor.

[0027] (2) The composite excitation wheel speed sensor of this application, through the design of composite excitation, makes the sensor structure more compact and the space utilization rate higher. The magnetic guide plate, as the carrier of the permanent magnet, is also a key component of the magnetic circuit, which can efficiently guide and concentrate the magnetic lines of force and reduce the loss of magnetic energy in the non-working area. At the same time, the stator teeth are directly set on the outer periphery of the magnetic guide plate, forming a precise working air gap with the rotor teeth, making the entire magnetic circuit system path short and efficient. This compact layout allows the sensor to have stronger performance while its physical volume is significantly compressed, meeting the strict installation requirements of modern aerospace for sensor miniaturization and lightweighting. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0029] Figure 1 This is an overall outline view of a composite excitation wheel speed sensor provided in an embodiment of the present invention;

[0030] Figure 2 A cross-sectional view of a set of composite excitation components provided in an embodiment of the present invention;

[0031] Figure 3 A cross-sectional view of a present invention comprising two sets of composite excitation components;

[0032] Figure 4 A cross-sectional view of a three-group composite excitation assembly provided in an embodiment of the present invention;

[0033] Figure 5 A perspective view of the rotor assembly of a composite excitation wheel speed sensor provided in an embodiment of the present invention;

[0034] Figure 6This is a cross-sectional view of the rotor assembly of a composite excitation wheel speed sensor provided in an embodiment of the present invention;

[0035] Figure 7 A perspective view of the stator assembly of a composite excitation wheel speed sensor according to an embodiment of the present invention;

[0036] Figure 8 This is a cross-sectional view of the stator assembly of a composite excitation wheel speed sensor provided in an embodiment of the present invention;

[0037] Wherein: 1-House, 2-Rotor assembly, 21-Rotor shaft, 211-First shaft section, 212-Second shaft section, 22-Rotor yoke, 23-Rotor end cover, 24-First bearing, 25-Second bearing, 26-Rotor tooth, 27-Bearing seat, 3-Stator assembly, 31-Stator shaft, 32-Composite excitation assembly, 321-Winding group, 3211-Winding support, 3212-Winding, 322-Magnetic guide plate, 3221-Disc-shaped section, 3222-Cylindrical section, 323-Stator tooth, 324-Permanent magnet, 33-Stator end cover, 4-Magnetic shielding plate, 5-First magnetic circuit space, 6-Second magnetic circuit space, 7-Stator pressing plate, 8-Rear cover, 9-Oil seal. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0039] The following is in conjunction with the appendix Figure 1 To be continued Figure 8 The invention is described in detail with specific embodiments.

[0040] See Figures 1 to 8This invention provides a composite excitation wheel speed sensor, comprising a housing 1, a rotor assembly 2 and a stator assembly 3 housed within the housing 1. The stator assembly 3 includes a stator shaft 31, a stator end cap 33 fixed to one end of the stator shaft 31, and at least one set of composite excitation components 32 sleeved on the stator shaft 31. The stator shaft 31 is fixed within the housing 1. The composite excitation component 32 includes a winding assembly 321, a magnetic guide plate 322, and a permanent magnet 324 fixed to the magnetic guide plate 322. The magnetization direction of the permanent magnet 324 is consistent with the direction of the magnetic field generated after the winding assembly 321 is energized. Stator teeth 323 are provided on the outer periphery of the magnetic guide plate 322. The rotor assembly 2 includes a rotor shaft 21, a rotor end cap 33 fixed to one end of the rotor shaft 21, and a stator end cap 323. The rotor end cover 23 and the rotor yoke 22 fixed on the rotor end cover 23, the rotor shaft 21 and the stator shaft 31 are axially spaced and coaxially arranged. The rotor shaft 21 is rotatably arranged on the housing 1 and one end of it extends out of the housing 1. The opposite end of the rotor shaft 21 and the stator shaft 31 is rotatably connected by the first bearing 24, and the inner ring of the first bearing 24 is connected to the rotor shaft 21, and the outer ring is supported on the stator shaft 31 by the bearing seat 27. In other words, the rotor shaft 21 and the stator shaft 31 of this application are designed on the same straight line and are axially spaced from each other. The rotor shaft 21 does not penetrate the entire housing 1, but is partially located inside the housing 1 and partially extends out of the housing 1, while the stator shaft 31 is completely located inside the housing 1. The stator end cover 33 and the rotor end cover 23 form a magnetic circuit space. The composite excitation assembly 32 is sequentially installed in the magnetic circuit space along the axial direction. The inner ring of the rotor yoke 22 is provided with rotor teeth 26 that are opposite to the stator teeth 323, so that when the rotor shaft 21 rotates, the magnetic resistance between the rotor teeth 26 and the stator teeth 323 changes periodically. It should be noted that the rotor yoke 22 in this application extends axially and extends from the rotor end cover 23 to the stator end cover 33, that is, it covers the entire magnetic circuit space in the axial direction.

[0041] In practical implementation, since the rotor shaft 21 and stator shaft 31 are arranged at intervals, they do not interfere with each other. When the rotor shaft 21 rotates, the stator shaft 31 does not rotate with it. The rotor shaft 21 drives the rotor yoke 22 to rotate synchronously, and the rotor teeth 26 on the inner ring of the rotor yoke 22 also rotate synchronously. When the tooth tip of the rotor tooth 26 is opposite to the tooth tip of the stator tooth 323, the magnetic reluctance of the magnetic circuit is small; when the tooth groove of the rotor tooth 26 is opposite to the tooth tip of the stator tooth 323, the magnetic reluctance of the magnetic circuit is large. During the rotation of the rotor shaft 21, the magnetic reluctance changes periodically, causing the inductance of the wheel speed sensor to change alternately, thereby outputting a larger wheel speed sensor signal amplitude.

[0042] This invention utilizes a permanent magnet 324 fixedly mounted on a magnetic plate 322, allowing the permanent magnet 324 and the winding assembly 321 to jointly serve as a magnetic source. The magnetization direction of the permanent magnet 324 aligns with the direction of the magnetic field generated by the energized winding assembly 321, forming the core of composite excitation. This design significantly enhances the initial magnetic field strength, and the permanent magnet 324 provides a stable magnetic field for the sensor that requires no external energy. The magnetic field generated by the energized winding assembly 321 is superimposed on this magnetic field, achieving a magnetic field enhancement effect. This allows the sensor to obtain a stronger effective working magnetic field within the same volume, or to significantly reduce the excitation current while maintaining the same output signal requirements, directly lowering the sensor's power consumption. Furthermore, the strong composite magnetic field causes a more dramatic change in magnetic reluctance during rotor shaft 21 rotation, thereby inducing an electrical signal with higher amplitude and better signal-to-noise ratio in the winding assembly 321.

[0043] In some embodiments, see Figure 2 A set of composite excitation components is arranged within the magnetic circuit space; the magnetic guide plate 322 and the stator end cover 33 are respectively located on both axial sides of the winding assembly 321, and the end of the magnetic guide plate 322 facing away from the winding assembly 321 abuts against the bearing seat 27; the winding assembly 321 includes a winding bracket 3211 and a winding 3212. The winding bracket 3211 is sleeved on the stator shaft 31, and a winding groove is formed on the outer side of the winding bracket 3211, and the winding 3212 is disposed in the winding groove. Through the design of the winding bracket 3211, the winding can be completed on a special equipment and pre-insulated and fixed, which can ensure the consistency and reliability of the winding quality. Then, it is assembled as an integral component on the stator shaft 31, and the winding groove on the winding bracket 3211 can precisely constrain the position of the winding.

[0044] In other embodiments, see Figure 3Two sets of composite excitation components are mounted on the stator shaft 31, and the two sets of composite excitation components are isolated from each other by a magnetic shielding plate 4. One set of composite excitation components is located between the stator end cover 33 and the magnetic shielding plate 4, and the other set of composite excitation components is located between the magnetic shielding plate 4 and the bearing housing 27. The setting of two sets of composite excitation components 32 can realize signal superposition and redundancy. When the sensor is working, the two sets of composite excitation components 32 can generate induction signals simultaneously, and the two signals can be superimposed to output a comprehensive signal with stronger amplitude and higher signal-to-noise ratio. In addition, the two sets of composite excitation components 32 constitute a redundant system. In practical applications, even if one set of composite excitation components 32 fails due to accidental damage, the other set of composite excitation components 32 can still work independently and output an effective wheel speed signal, avoiding the risk of the sensor being completely paralyzed due to the failure of a single component. The application of the magnetic shielding plate 4 effectively blocks the direct coupling of the magnetic fields between the two sets of excitation components 32, allowing them to form independent, closed, and precise high-efficiency magnetic circuits. As can be seen, the stator end cover 33, the magnetic shielding plate 4, and the bearing seat 27 are inherent structural components in the sensor. Using them as the positioning and installation boundaries of the two sets of composite excitation components 32 achieves reasonable utilization of the axial space inside the sensor, avoids additional axial dimension due to the installation of composite excitation components 32, and ultimately achieves the miniaturization and compactness requirements of the sensor as a whole.

[0045] Furthermore, two magnetic guide plates 322 respectively abut against the axial end faces of the magnetic shielding plate 4. One winding assembly 321 is located between the magnetic guide plate 322 and the stator end cover 33, and the other winding assembly 321 is located between the magnetic guide plate 322 and the bearing seat 27. The winding assembly 321 includes a winding bracket 3211 and a winding 3212. The winding bracket 3211 is sleeved on the stator shaft 31, and a winding groove is formed on the outer side of the winding bracket 3211. The winding 3212 is disposed in the winding groove. Through the design of the winding bracket 3211, the winding can be completed on a special equipment and pre-insulated and fixed, which can ensure the consistency and reliability of the winding quality. Then, it is installed as an integral component on the stator shaft 31, and the winding groove on the winding bracket 3211 can precisely constrain the position of the winding.

[0046] For further details, please refer to [link / reference]. Figure 8In the above embodiment, the magnetic guide plate 322 includes a disc-shaped portion 3221 fitted onto the stator shaft 31 and a cylindrical portion 3222 extending axially from the outer periphery of the disc-shaped portion 3221. At least a portion of the cylindrical portion 3222 surrounds the winding assembly 321, and stator teeth 323 are provided on the outer periphery of the cylindrical portion 3222. The permanent magnet 324 is disposed on the disc-shaped portion 3221 at the end opposite to the winding assembly 321. The cylindrical portion 3222 and the disc-shaped portion 3221 together form a highly efficient magnetic guide structure, providing a low magnetic resistance closed path for the magnetic field generated by the permanent magnet 324 and the winding assembly 321. This efficiently gathers and guides the magnetic lines of force to the stator teeth 323, greatly reducing the loss of magnetic energy in the air and improving the magnetic circuit efficiency. Furthermore, through the above-mentioned composite excitation design, the sensor structure is more compact and the space utilization rate is higher. The magnetic guide plate 322, serving as the carrier of the permanent magnet 324, is also a key component of the magnetic circuit. It efficiently guides and concentrates magnetic lines of force, reducing magnetic energy loss in non-working areas. Simultaneously, the stator teeth 323 are directly positioned on the outer periphery of the magnetic guide plate 322, forming a precise working air gap with the rotor teeth 26, resulting in a short and efficient magnetic circuit system. This compact layout allows the sensor to achieve enhanced performance while significantly reducing its physical size, meeting the stringent installation requirements of modern aerospace for sensor miniaturization and weight reduction.

[0047] This invention can increase the output voltage amplitude by changing the magnitude of the excitation current, thereby meeting the requirement of low speed and high amplitude output voltage of the wheel speed sensor under the condition of limited excitation current. At the same time, it can make the wheel speed sensor smaller and meet the requirement of limited size.

[0048] For further details, please refer to [link / reference]. Figure 7 and Figure 8 The stator shaft 31 is fixedly connected to the stator end cover 33 at the end away from the rotor shaft 21. Preferably, the stator end cover 33 is integrally formed with the stator shaft 31, and its end face away from the rotor shaft 21 is flush with the end face of the stator shaft 31. The integrally formed structure design fundamentally eliminates the assembly error and connection gap between the stator end cover 33 and the stator shaft 31, ensuring the rigidity and positioning accuracy of the stator assembly 3 as a whole. This provides a solid foundation for a stable and uniform working air gap between the rotor teeth 26 and the stator teeth 323. At the same time, the flush end face design can serve as an axial positioning reference during assembly, enabling the stator assembly 3 to be quickly and accurately positioned when installed into the housing 1, greatly simplifying the assembly process and improving production efficiency.

[0049] For further details, please refer to [link / reference]. Figure 5 and Figure 6The rotor shaft 21 is fixedly connected to the rotor end cover 23 at one end near the stator shaft 31. Preferably, the rotor end cover 23 and the rotor shaft 21 are integrally formed, and the two ends of the rotor shaft 21 protrude from the rotor end cover 23 respectively, forming a first shaft portion 211 and a second shaft portion 212. A first bearing 24 and a second bearing 25 are respectively provided on the first shaft portion 211 and the second shaft portion 212. The inner ring of the first bearing 24 is connected to the first shaft portion 211 of the rotor shaft 21, and the outer ring is supported on the stator shaft 31 by the bearing seat 27. The inner ring of the second bearing 25 is connected to the rotor end cover 23. The second shaft portion 212 of shaft 21 is connected, and the outer ring is supported on the housing 1. The design process of integrally forming rotor shaft 21 and rotor end cover 23 fundamentally eliminates the assembly error between end cover and shaft, ensuring that the center line of rotor yoke 22 coincides with that of rotor shaft 21. The first shaft portion 211 and the second shaft portion 212 protruding at both ends provide the installation reference for the first bearing 24 and the second bearing 25, so that the entire rotor assembly 2 can be stably positioned inside the housing through two-point support, ensuring the uniformity and stability of the air gap between rotor teeth 26 and stator teeth 323.

[0050] Specifically, the stator end cover 33, rotor yoke 22, magnetic guide plate 322, and stator shaft 31 form a first magnetic circuit space 5, within which one set of windings 321 is located. The rotor end cover 23, bearing housing 27, rotor yoke 22, magnetic guide plate 322, and stator shaft 31 form a second magnetic circuit space 6, within which another set of windings 321 is located. The volume of the second magnetic circuit space 6 is larger than that of the first magnetic circuit space 5. The magnetic path of the first magnetic circuit space 5 is relatively short, and the magnetic reluctance is relatively small, which is beneficial for fast response and excellent performance under high-speed conditions. The larger volume of the second magnetic circuit space 6 can establish and accommodate a stronger magnetic field, generating a signal with higher amplitude and better signal-to-noise ratio at low speeds, effectively improving the problem of weak signals from traditional sensors at extremely low speeds.

[0051] Furthermore, the disc-shaped portion 3221 of the magnetic guide plate 322 has an annular groove on its end face facing the winding assembly 321, and the permanent magnet 324 has an annular structure and is embedded in the annular groove. The annular groove provides a positioning slot and mounting position for the annular permanent magnet 324, ensuring that its position is reliably defined in the radial and axial directions, effectively preventing displacement and loosening during assembly. This tight fitting structure mechanically integrates the permanent magnet 324 with the magnetic guide plate 322, greatly enhancing the structural rigidity and reliability of the entire assembly. Preferably, the permanent magnet 324 is fixed in the annular groove of the magnetic guide plate 322 by adhesive bonding.

[0052] In some embodiments, see Figure 4At least three sets of composite excitation components are sleeved on the stator shaft 31. These three sets of composite excitation components are isolated from each other by magnetic isolation plates 4. The two sets of composite excitation components located on opposite sides of the axial direction have the same structure. Specifically, they are similar to... Figure 2 , Figure 3 as well as Figure 8 The composite excitation components in the middle have the same structure, as do the other composite excitation components. The outer wall of the magnetic guide plate 322 of the middle composite excitation component has an annular groove, the permanent magnet 324 is embedded in the opposite side walls of the annular groove, the winding group 321 is located in the annular groove, and the outer wall of the magnetic guide plate 322 has stator teeth 323 that cooperate with the rotor teeth 26. Setting three or more sets of composite excitation components further realizes signal superposition and redundancy. When the sensor is working, all composite excitation components can generate induction signals simultaneously, outputting a comprehensive signal with stronger amplitude and higher signal-to-noise ratio. At the same time, at least three sets of composite excitation components also constitute a redundant system, avoiding the situation where the sensor is completely paralyzed due to the failure of a single composite excitation component.

[0053] For further details, please refer to [link / reference]. Figure 2 A stator clamping plate 7 is provided on the side of the stator end cover 33 facing away from the winding assembly 321. The stator clamping plate 7 is connected to the housing 1 by a threaded structure to press the stator assembly 3 tightly inside the housing 1. By tightening the stator clamping plate 7, a controllable and uniform axial preload can be applied to the entire stator assembly 3, firmly pressing it against the mounting reference surface of the housing 1. This rigid fixation effectively prevents the stator assembly from axial movement or slight rotation due to continuous vibration and impact during sensor operation, ensuring the accuracy and stability of signal output.

[0054] For further details, please refer to [link / reference]. Figure 2 The rotor assembly 2 and stator assembly 3 are sealed within the housing 1 at both ends by a rear cover 8 and an oil seal 9, respectively. The oil seal 9 is fitted onto the rotor shaft 21, and its outer ring is sealed to the housing 1. A mounting stop is provided at the end of the housing 1 furthest from the rotor shaft 21, and the rear cover 8 is mounted onto the housing 1 through the mounting stop. The combination of the rear cover 8 and the oil seal 9 forms a dual protection system against harsh external environments. The oil seal 9, fitted onto the high-speed rotating rotor shaft 21, effectively prevents external dust, mud, and other contaminants from entering the housing 1 along the bearing clearance. The rear cover 8 statically seals the other end of the housing 1, forming a complete sealed cavity together with the housing 1. This dynamic and static sealing scheme completely isolates the internal rotor assembly 2, stator assembly 3, and the precision magnetic circuit air gap from the outside, ensuring long-term stable operation and an ultra-long service life of the sensor's core components under harsh operating conditions.

[0055] Furthermore, the composite excitation wheel speed sensor is cylindrical in shape, with a diameter of 30mm to 35mm and a height of 28mm to 32mm. Preferably, the wheel speed sensor of this application has a diameter of 32mm, a height of 30mm, and a volume of 24115mm². 3 In comparison, existing wheel speed sensors have a diameter of 43.5 mm, a height of 51.5 mm, and a volume of 76,500 m³. 3 Therefore, it can be seen that this application has successfully integrated two independent composite excitation magnetic circuits and all support structures within such a compact size, realizing the miniaturization of the sensor in terms of physical form.

[0056] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A composite excitation type wheel speed sensor, comprising a housing, and a stator assembly and a rotor assembly housed within the housing, characterized in that: The stator assembly includes a stator shaft, a stator end cover fixed to one end of the stator shaft, and at least one set of composite excitation assemblies sleeved on the stator shaft. The stator shaft is fixed inside the housing. The composite excitation assembly includes a winding assembly, a magnetic guide plate, and a permanent magnet fixed to the magnetic guide plate. The magnetization direction of the permanent magnet is consistent with the direction of the magnetic field generated after the winding assembly is energized. Stator teeth are provided on the outer periphery of the magnetic guide plate. The rotor assembly includes a rotor shaft, a rotor end cap fixed to one end of the rotor shaft, and a rotor yoke fixed to the rotor end cap. The rotor shaft and the stator shaft are axially spaced and coaxially arranged. The rotor shaft is rotatably mounted on the housing and one end of it extends out of the housing. The ends of the rotor shaft opposite to the stator shaft are rotatably connected by a first bearing, and the inner ring of the first bearing is connected to the rotor shaft, while the outer ring is supported on the stator shaft by a bearing seat. The stator end cover and the rotor end cover form a magnetic circuit space. The composite excitation assembly is installed sequentially in the magnetic circuit space along the axial direction. The inner ring of the rotor yoke is provided with rotor teeth that are opposite to the stator teeth, so that when the rotor shaft rotates, the magnetic resistance between the rotor teeth and the stator teeth changes periodically.

2. The composite excitation wheel speed sensor according to claim 1, characterized in that: A set of the composite excitation components is arranged in the magnetic circuit space; the magnetic guide plate and the stator end cover are respectively located on both sides of the axial direction of the winding group, and the end of the magnetic guide plate facing away from the winding group abuts against the bearing seat; the winding group includes a winding bracket and a winding, the winding bracket is sleeved on the stator shaft, and a winding groove is formed on the outer side of the winding bracket, and the winding is arranged in the winding groove.

3. The composite excitation wheel speed sensor according to claim 1, characterized in that: Two sets of the composite excitation components are sleeved on the stator shaft, and the two sets of composite excitation components are isolated by a magnetic shielding plate; one set of composite excitation components is located between the stator end cover and the magnetic shielding plate, and the other set of composite excitation components is located between the magnetic shielding plate and the bearing seat; The two magnetic guide plates abut against the axial end faces of the magnetic shielding plate respectively. One winding group is located between the magnetic guide plate and the stator end cover, and the other winding group is located between the magnetic guide plate and the bearing seat. The winding group includes a winding bracket and a winding. The winding bracket is sleeved on the stator shaft, and a winding groove is formed on the outer side of the winding bracket. The winding is disposed in the winding groove.

4. The composite excitation wheel speed sensor according to claim 2 or 3, characterized in that: The magnetic guide plate includes a disc-shaped portion fitted on the stator shaft and a cylindrical portion extending axially from the outer periphery of the disc-shaped portion. At least a portion of the cylindrical portion surrounds the winding assembly. The stator teeth are provided on the outer periphery of the cylindrical portion. The permanent magnet is disposed on the disc-shaped portion at one end opposite to the winding assembly.

5. The composite excitation wheel speed sensor according to claim 4, characterized in that: The disc-shaped portion has an annular groove on one end face facing the winding assembly, and the permanent magnet has an annular structure and is embedded in the annular groove.

6. The composite excitation wheel speed sensor according to claim 1, characterized in that: At least three sets of the composite excitation components are sleeved on the stator shaft. The at least three sets of composite excitation components are isolated from each other by magnetic isolation plates. The two sets of composite excitation components located on both sides of the axial direction have the same structure, and the remaining composite excitation components have the same structure. The outer wall of the magnetic guide plate of the composite excitation assembly located in the middle has an annular groove. The permanent magnet is embedded in the opposite side walls of the annular groove. The winding assembly is arranged in the annular groove. The outer wall of the magnetic guide plate is provided with stator teeth that cooperate with the rotor teeth.

7. The composite excitation wheel speed sensor according to claim 1, characterized in that: A stator pressure plate is provided on the side of the stator end cover facing away from the winding assembly. The stator pressure plate is connected to the housing via a threaded structure to press the stator assembly into the housing.

8. The composite excitation wheel speed sensor according to claim 1, characterized in that: The rotor assembly and stator assembly are sealed inside the housing by a rear cover and an oil seal, respectively; The oil seal is fitted onto the rotor shaft, and its outer ring is sealed to the housing. The housing is provided with a mounting stop at one end away from the rotor shaft, and the rear cover is mounted on the housing through the mounting stop.

9. The composite excitation wheel speed sensor according to claim 1, characterized in that: The composite excitation wheel speed sensor is cylindrical in shape, with a diameter of 30mm to 35mm and a height of 28mm to 32mm.

10. The composite excitation wheel speed sensor according to claim 3, characterized in that: The stator end cover, rotor yoke, magnetic plate, and stator shaft form a first magnetic circuit space, in which a set of windings is located within the first magnetic circuit space; The rotor end cover, bearing housing, rotor yoke, magnetic guide plate, and stator shaft form a second magnetic circuit space. Another set of windings is located within the second magnetic circuit space, and the volume of the second magnetic circuit space is greater than the volume of the first magnetic circuit space.

Images