CN103807329A - Eddy current retarder device based on magnetorheological effect - Google Patents

Abstract

The invention relates to an eddy current retarder based on the magnetorheological effect, which comprises a rotor disk, a stator assembly, a transmission shaft and a magnetorheological fluid. Stator assembly includes bearing sleeve, stator housing, etc. The stator assembly is located in the middle, and the two rotor disks are respectively placed in the stator casing on both sides of the stator assembly. The gap between the casing and the rotor disk is filled with magnetorheological fluid, and eight excitation devices are respectively fixed on the stator casings on both sides. on the inner shell of the body. In this structure, the magnetorheological fluid with high magnetic permeability and extremely low electrical conductivity is used to replace the air gap between the rotor and the stator, thereby reducing the reluctance of the magnetic circuit. At the same time, under the action of a magnetic field, the magnetorheological fluid changes from Newtonian fluid with extremely low viscosity to Bingham fluid with high shear yield stress. During braking, the braking torque generated by the eddy current and the braking torque generated by the magneto-rheological fluid act simultaneously. The eddy current retarder with this structure has the characteristics of energy saving, low coil heat generation, large braking torque, good controllability of braking torque and good low-speed performance.

Description

A kind of eddy current retarder device based on magnetorheological effect

technical field

The invention relates to an eddy current retarder based on magnetorheological effect, in particular to an eddy current retarder using magnetorheological fluid as a magnetic conduction medium and a working medium at the same time.

Background technique

With the development of the automobile industry, the driving speed of automobiles is getting faster and faster, and the braking efficiency and safety of automobiles have also received extensive attention. In the case of continuous braking for a long time, traditional brakes will produce thermal fading, which will greatly reduce the braking efficiency and seriously affect the safety performance of the car. With the introduction of relevant national automobile safety regulations in recent years, auxiliary brakes must be installed on large trucks and buses. The auxiliary brake of the automobile can bear most of the braking energy, reduce the braking load of the service brake, and greatly improve the safety of the automobile. The main auxiliary braking devices currently used are eddy current retarders and hydraulic retarders.

The existing eddy current retarders have the following disadvantages:

1. There is a certain air gap between the pole shoe and the rotor of the eddy current retarder. Due to the extremely low permeability of the air, the magnetic resistance of the magnetic circuit is very large. Therefore, to generate a sufficiently large eddy current effect in the rotor, the excitation coil must pass A large excitation current will cause the temperature of the excitation coil to be too high, and the battery load will be large, which will affect the life of the battery.

2. The braking torque of the eddy current retarder is not only related to the current passing into the excitation coil, but also has a great relationship with the speed of the vehicle. The higher the vehicle speed, the greater the braking torque; the lower the speed, the smaller the braking torque. Therefore, when the vehicle is at low speed, the braking torque of the eddy current retarder is small, and the retarding effect is not ideal.

Current hydraulic retarders have the following disadvantages:

1. The structure of the hydraulic retarder is complicated, the manufacturing precision is high, and the cost is high.

2. The braking torque of the hydraulic retarder is very small at low speed, which cannot meet the braking requirements; and when braking, it takes a certain time for the working hydraulic pressure to enter the working chamber, resulting in a long braking response time.

Magnetorheological fluid is a new type of intelligent material, which is a suspension formed by dispersing and dissolving soft magnetic particles with high magnetic permeability and low hysteresis in insulating base fluid. Under the action of a magnetic field, the apparent viscosity of the magnetorheological fluid increases rapidly within a few milliseconds, and the shear yield stress increases with the increase of the magnetic field. When the magnetic field is removed, it quickly returns to the original low-viscosity state. . This liquid is not only a stable suspension whose rheological properties can be controlled with the change of the applied magnetic field, but also has high magnetic permeability, low electrical conductivity and excellent thermal stability. So in recent years, it has been widely used in the research of new brakes, and has a good application prospect.

At present, magnetorheological fluid brakes are mostly disc brakes (for example, see Chinese patent 201110427735.9, US patent US8631917B2), which use magnetorheological fluid as brake working fluid to fill between the rotor and stator, and make the magnetorheological fluid The shear yield stress increases to achieve the effect of braking. However, only using the rheological characteristics of magnetorheological fluid under the action of an external magnetic field to generate braking torque for braking, the braking torque provided is very limited. Chinese patent 201210434149.1, entitled "Independent hydraulic retarder based on magnetorheological fluid and its control method", uses magnetorheological fluid as the working fluid of the hydraulic retarder, and through the rheology of the magnetorheological fluid characteristics to increase the braking torque and improve the low-speed performance of the retarder, but its structure is complex, it is difficult to design an excitation device that makes the viscosity of the magnetorheological fluid change uniformly, and the magnetorheological fluid with uneven viscosity has a flow field in the vortex cavity The complexity is difficult to guarantee the stability of the braking effect.

Contents of the invention

In view of the deficiencies in the prior art, the object of the present invention is to provide a novel retarder device in which the magneto-rheological effect and the eddy current effect work together, it has no air gap between the stator and the rotor, the excitation current is small, the coil heat is low, It has the characteristics of large braking torque, good low-speed braking performance, good controllability of braking torque and simple structure.

Technical scheme of the present invention is:

An eddy current retarder device based on the magneto-rheological effect, characterized in that it includes a bearing sleeve and a transmission shaft arranged in the bearing sleeve, and a stator shell is respectively provided at both ends of the bearing sleeve The stator housing is equipped with a rotor disk connected to the transmission shaft, the magnetorheological fluid is filled between the rotor disk and the stator housing, and the outer circumference of the bearing sleeve between the two stator housings is provided with A magnetic core, an excitation coil is wound around the magnetic core, and both ends of the magnetic core are fixedly connected to the inner wall of the stator housing through pole shoes.

Wherein, the stator housing includes an outer housing, an inner housing and a cylindrical housing.

The pole shoe, the magnetic core, and the excitation coil form an excitation device, and there are eight excitation devices, and the centers of the eight excitation devices are respectively located between the stator housings on both sides, and a pair of pole shoes of each excitation device Evenly distributed and fixed on the same indexing circle of the inner casing of the stator casings on both sides, and the magnetic poles of the two adjacent excitation devices are always opposite.

The shape of the pair of pole shoes is two protruding sectors with different sizes, and the inner housing is provided with a fan-shaped through slot matching the pole shoes, and the pole shoes are inserted into the fan-shaped through slots of the inner housing In this case, a closed disk is formed with the inner casing, and the pole piece is in direct contact with the magnetorheological fluid filled in the stator casing.

There is an exhaust hole on the inner shell, and a liquid injection hole on the outer shell, and the liquid injection hole and the exhaust hole are blocked by slotted flat head set screws; there are two holes on both sides of the cylindrical shell. A threaded hole for connection to an external stator.

The advantages of the present invention are:

1. The magnetorheological fluid with high magnetic permeability and extremely low conductivity is used to replace the non-magnetic air gap in the traditional eddy current retarder, which greatly reduces the magnetic resistance in the magnetic circuit. Therefore, under the same excitation current, the magnetic flux passing through the rotor disk can be significantly increased, so that the braking torque of the retarder can be significantly increased. Under the premise of obtaining the same retarding effect, the excitation current required by the excitation coil is significantly reduced, thereby greatly reducing the heat generation of the excitation coil and the load on the battery.

2. In this device, the braking torque generated by the magneto-rheological effect is only related to the strength of the external magnetic field, and has nothing to do with the rotational speed of the rotor disk. Therefore, when braking, the braking torque generated by the magneto-rheological effect and the braking torque generated by the eddy current effect act simultaneously, which not only increases the maximum braking torque of the eddy current retarder, but also improves the speed of the eddy current retarder. low-speed braking performance and braking torque controllability.

3. The shear yield stress of magnetorheological fluid can increase rapidly within a few milliseconds, not only will not reduce the braking response time of the eddy current retarder, but also the current through the excitation coil can simultaneously control the shear of the magnetorheological fluid The yield stress and the magnetic flux through the rotor disk make the current control of the device simple and reliable.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Figure 2 is a right side view of the outer casing.

Figure 3 is a left side view of the inner shell.

Figure 4 is a left side view of the cylindrical shell.

Figure 5 is a left view of the pole shoe.

Fig. 6 is a schematic diagram of the magnetic circuit in the working state.

Among them: 1. Cylindrical shell; 2. Outer shell; 3. Rotor disc; 4. Magnetorheological fluid; 5. Inner shell; 6. Ordinary flat key; 7. Outer lip seal ring; 8. Bearing Cover; 9. Pole shoe; 10. Sector seal ring; 11. Inner bearing; 12. Inner lip seal ring; 13. Outer bearing; 14. Transmission shaft; 15. Spring retaining ring; 16. Sleeve; 17. Bearing Sleeve; 18. Countersunk head screw; 19. Slotted flat end set screw; 20. Magnetic core; 21. Exciting coil; 22. Sealing washer.

Detailed ways

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

As shown in Figure 1, the present invention is a symmetrical structure with a central stator assembly and double rotors on both sides, including a cylindrical shell 1 (2 pieces), an outer shell 2 (2 pieces), a rotor disk 3 (2 pieces ), magnetorheological fluid 4, inner housing 5 (2 pieces), ordinary flat key 6 (2 pieces), outer lip seal ring 7 (2 pieces), bearing cap 8 (2 pieces), pole shoe 9 (16 pcs), sector seal ring 10 (4 pcs), inner bearing 11 (2 pcs), inner lip seal ring 12 (2 pcs); outer bearing 13 (2 pcs), transmission shaft 14, spring retaining ring 15 (4 pcs ), sleeve 16 (2 pcs), bearing sleeve 17, countersunk head screw 18 (16 pcs), slotted flat end set screw 19 (4 pcs), magnetic core 20 (8 pcs), field coil 21 (8 pcs ), sealing gasket 22 (4 pieces). Among them, the cylindrical shell 1, the outer shell 2, the inner shell 5, and the bearing sleeve 17 form a stator assembly. The cylindrical case 1, the outer case 2, and the inner case 5 are assembled into a stator case. The rotor discs 3 are respectively placed in the stator housings on both sides of the rotor. The bearing sleeve 17 is located between the two stator housings, and the two sides are respectively fixed on the two stator housings. The pole shoe 9, the magnetic core 20, and the excitation coil 21 form the excitation device. The centers of the eight excitation devices are respectively located between the stator housings on both sides, and are evenly distributed and fixed on the inner shells of the stator housings on both sides through the two pole shoes 9. On the same indexing circle of body 5, and the magnetic poles of two adjacent excitation devices are always opposite.

As shown in Figure 2 and Figure 3, there is a vent hole 24 on the inner shell 5, and a liquid injection hole 23 on the outer shell 2, and the liquid injection hole 23 and the vent hole 24 are all blocked by slotted flat head set screws live. After the retarder is installed, the slotted flat-head set screw 19 can be taken out, and the magnetorheological fluid 4 can be evenly filled in the gap between the rotor disk 3 and the stator casing to replace the air between the rotor disk 3 and the stator casing. Gap.

An excitation device is composed of two pole pieces 9 , a magnetic core 20 , and an excitation coil 21 . The two pole pieces 9 are symmetrically distributed on both sides of the magnetic core 20 and connected by set screws 18 with slotted flat ends.

As shown in Figure 3 and Figure 5, the shape of the pole shoe 9 is two raised sectors of different sizes, which match with the through groove 25 on the inner casing 5 of the stator casing, and the pole shoe 9 is directly inserted into the inner casing 5 In this process, the pole piece 9 is in direct contact with the magnetorheological fluid 4 . It is fixed with screws, and the fan-shaped sealing ring 10 is sealed to prevent the magnetorheological fluid 4 from leaking.

The cylindrical shell 1, the outer shell 2, and the inner shell 5 are assembled into a stator shell through screw connection, wherein the cylindrical shell 1, the outer shell 2, and the inner shell 5 are all magnetic isolation materials (such as low carbon steel , aluminum), between the inner shell 5 and the cylindrical shell 1, between the outer shell 2 and the cylindrical shell 1 are sealed with gaskets 22, so as to avoid the leakage of the magneto-rheological fluid 4.

The inner casing 5 of the stator casing on both sides is connected with the two sides of the bearing sleeve 17 by screws, and the bearing sleeve 117 is equipped with a pair of symmetrically distributed inner bearings 11 and sleeves 16, and the sleeve 16 is used to fix the inner bearing 11 . The shoulder inside the bearing sleeve 17 is used to determine the installation position of the inner bearing 11 , and the sleeve 16 is used to fix the position of the inner bearing 11 .

Bearing caps 8 on both sides are connected with the outer casing by screws, and outer bearings 13 are respectively housed in the bearing caps 8 .

Both the rotor disk 3 and the drive shaft 14 are connected by ordinary flat keys 6 , and two spring retaining rings 15 are respectively installed on both sides of the rotor disk 3 for fixing the axial position of the rotor disk 3 .

The outer lip-shaped sealing ring 7 and the inner lip-shaped sealing ring 12 are used for axial sealing of the stator housing to prevent the magneto-rheological fluid 4 from leaking from both axial sides of the stator housing. The outer lip seal ring 7 is installed in the groove of the outer shell 2, and the other end is fixed by the bearing cover 8, and the inner lip seal ring 12 is installed in the groove of the inner shell 5, and the other end is fixed by the shoulder of the drive shaft 14 .

As shown in FIG. 4 , there are two threaded holes 26 on both sides of the cylindrical shell 1 for connecting with an external stator.

As shown in Figure 6, in the non-braking state, the excitation coil 21 is not energized, and there is no magnetic field in the device. At this time, the magnetorheological fluid 4 is a Newtonian fluid with extremely low viscosity, and the resistance of the rotor disk 3 to rotate is extremely small. There is no braking effect, so the rotor disc 3 rotates freely within the stator housing. In the braking state, the excitation coil 21 is energized, and a magnetic field closed circuit is generated in the device. Since the stator housing is made of a magnetic isolation material, the magnetic circuit does not pass through the stator housing, so its magnetic conduction circuit is: magnetic core 20-1, pole shoe 9-1, magnetorheological fluid 4-1, rotor disc 3-1, magnetorheological fluid 4-1, pole shoe 9-2 of adjacent excitation device, magnetic core 20-2 of adjacent excitation device, Pole shoe 9-3, magnetorheological fluid 4-2, rotor disc 3-2, magnetorheological fluid 4-2, pole shoe 9-4, and magnetic core 20-1 of the adjacent excitation device. As the rotor disk 3 rotates in the magnetic field and cuts the magnetic field, eddy currents are generated on the rotor disk 3 . Under the action of the magnetic field, the eddy current causes the rotor disc 3 to generate a braking torque. Since the conductivity of the magnetorheological fluid 4 is extremely low, which is equivalent to an insulator, no eddy current is generated inside the magnetorheological fluid. At the same time, the magnetorheological fluid 4 in direct contact with the pole piece 9 is transformed from a Newtonian fluid with extremely low viscosity to a Bingham fluid with a high shear yield stress under the action of a magnetic field, thereby generating a braking torque on the rotor disk 3 . The two braking torques act at the same time to produce a retarding braking effect.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (5)

1. A kind of eddy current retarder device based on magneto-rheological effect, it is characterized in that: comprise a bearing sleeve and a transmission shaft that is located in the bearing sleeve, the two ends of described bearing sleeve are respectively provided with certain The sub-housing, the rotor disk connected to the transmission shaft is installed in the stator casing, the magnetorheological fluid is filled between the rotor disk and the stator casing, and the outer circumference of the bearing sleeve between the two stator casings A magnetic core is provided, and an excitation coil is wound on the magnetic core, and both ends of the magnetic core are fixedly connected to the inner wall of the stator housing through pole shoes. 2 . The magneto-rheological effect-based eddy current retarder device according to claim 1 , wherein the stator housing includes an outer housing, an inner housing and a cylindrical housing. 3 . 3. A kind of eddy current retarder device based on magneto-rheological effect according to claim 2, characterized in that: said pole shoe, magnetic core, and excitation coil form an excitation device, and said excitation device is 8 The centers of the 8 excitation devices are respectively located between the stator housings on both sides, and a pair of pole pieces of each excitation device are evenly distributed and fixed on the same indexing circle of the inner housings of the stator housings on both sides, and The magnetic poles of two adjacent exciters are always opposite. 4. The eddy current retarder device based on the magneto-rheological effect according to claim 3, characterized in that: the shape of the pair of pole pieces is two protruding sectors with different sizes, and the The inner housing is provided with fan-shaped through grooves matching with the pole shoes, and the pole shoes are inserted into the fan-shaped through grooves of the inner housing to form a closed disc with the inner housing, and the pole shoes and the stator housing filled The magnetorheological fluid is in direct contact. 5. The eddy current retarder device based on the magneto-rheological effect according to claim 2, characterized in that: there are vent holes on the inner casing, and liquid injection holes are arranged on the outer casing, and the liquid injection Both the hole and the exhaust hole are blocked by slotted flat-head set screws; two threaded holes are respectively provided on both sides of the cylindrical shell for connecting with the external stator.

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