Magnetic transmission speed reducer and built-in motor of power-assisted bicycle

Abstract

The utility model discloses a magnetic transmission speed reducer and a built-in motor of a power-assisted bicycle, and belongs to the power-assisted technology of bicycles. An existing middle motor is large in size, low in rotating efficiency and high in working noise. The modulation ring is arranged between the first rotor and the first stator, power is transmitted through the magnetic field coupling effect, the first air gap is formed between the modulation ring and the first stator, and the second air gap is formed between the modulation ring and the first rotor. Magnetic fields generated by the first rotor and the first stator are modulated by the modulation ring and then generate a series of space harmonic magnetic fields in the first air gap and the second air gap, stable output torque is generated on the modulation ring through magnetic field coupling, and the effects of speed reduction and torque amplification are achieved. Due to the friction-free characteristic of magnetic transmission and the ultrahigh torque density brought by the magnetic gathering structure and the high-permeability magnetic material, the system efficiency is improved, and the operation noise is reduced.

Description

Technical Field

[0001] The utility model belongs to the assisting technology of the mid - motor of a technical - assisted bicycle, and particularly relates to a magnetic - drive reduction device and a mid - motor of an assisted bicycle. Background Art

[0002] The mid - motor of an assisted bicycle or a bicycle usually outputs after the motor is decelerated by a reduction device. The reduction device among them is a gear reduction device, a cycloidal pin reduction device or a harmonic reduction device, which makes the mid - motor have a large volume, low rotation efficiency, high noise during operation, and a short service life. Content of the Utility Model

[0003] The technical problem to be solved and the technical task proposed by the utility model is to overcome at least one of the defects of the existing mid - motor, such as large volume, low rotation efficiency, high noise during operation, and short service life, and provide a magnetic - drive reduction device and a mid - motor of an assisted bicycle. The aim is to achieve deceleration through magnetic drive to achieve the purpose of the utility model.

[0004] To achieve the above - mentioned purpose, the magnetic - drive reduction device of the utility model is characterized by including a first stator, a first rotor and a modulation ring, wherein:

[0005] The first stator, which includes a first stator magnetic - pole assembly for providing a constant first stator magnetic field;

[0006] The first rotor, which includes a first rotor permanent magnet, and a first rotor magnetic - pole assembly for providing a first rotor magnetic field that rotates with the first rotor. The first rotor is located inside the first stator and is coaxial with the first stator;

[0007] The modulation ring, which is located between the first rotor and the first stator, is coaxial with the first rotor and the first stator, maintains a first air gap between the modulation ring and the first stator, and maintains a second air gap between the modulation ring and the first rotor;

[0008] The first stator and the first rotor are configured with different pole - pair numbers, so that the magnetic field in the first air gap is coupled with the magnetic field in the second air gap, and the rotation from the first rotor is output after being decelerated by the modulation ring.

[0009] The utility model realizes deceleration through magnetic drive. On the premise of limited installation space for the mid - motor, it improves the maximum output torque, thereby improving the motor operation efficiency and reducing the overall noise of the motor.

[0010] Preferably, the magnetic field of the first stator converges magnetically inward, and the magnetic field of the first rotor converges magnetically outward. In particular, the magnetic fields of both the first stator magnetic - pole assembly and the first rotor magnetic - pole assembly adopt the Halbach Array structure, which greatly improves the magnetic - field strength in the space where the modulation ring is located.

[0011] Preferably, the first rotor magnetic pole assembly is formed by magnetizing the first rotor permanent magnet in blocks and splicing them together, with a single pole divided into four pieces, and the whole is magnetized outward; the first stator magnetic pole assembly is formed by magnetizing the first stator permanent magnet in blocks and splicing them together, with a single pole divided into two pieces, which are magnetized radially and tangentially, and the whole is magnetized inward. In this way, a stronger magnetic field is provided to achieve greater torque transmission

[0012] Preferably, the number of first rotor pole pairs is p1, the first rotor comprises 8×p1 first rotor permanent magnets, and the magnetization directions of two adjacent first rotor permanent magnets differ by (45-360 / (8×p1)) degrees, so as to maximize the utilization of magnetic force and ensure easy implementation in terms of process.

[0013] Preferably, the axial projection profile of the first rotor permanent magnet is sector-shaped, and each first rotor permanent magnet has the same size, with a radial thickness of H1 and an average circumferential width of W1, H1 / W1=0.8-1.5, so as to maximize the utilization of magnetic force while ensuring process feasibility.

[0014] Preferably, the first stator permanent magnet is configured in any of the following ways:

[0015] (1) The axial projection profiles of the first stator permanent magnets are all sector-shaped and of the same size. The first stator permanent magnets are divided into radial permanent magnets and tangential permanent magnets. The radial permanent magnets are radially magnetized, and the tangential permanent magnets are tangentially magnetized. The radial permanent magnets and the tangential permanent magnets are spliced ​​at intervals to form a first stator magnetic pole assembly. The magnetization directions of two adjacent radial permanent magnets are opposite, and the magnetization directions of two adjacent tangential permanent magnets are opposite. The radial thickness of the first stator permanent magnet is H3, the circumferential average width of the first stator permanent magnet is W3, and W3 / H3=0.52-0.6. The magnetic circuit is optimized and the output torque is maximized.

[0016] (2) The axial projection profile of each first stator permanent magnet is a sector. The first stator permanent magnet is divided into a large permanent magnet and a small permanent magnet. The large permanent magnet is magnetized radially, and the small permanent magnet is magnetized tangentially. The large permanent magnet and the small permanent magnet are spliced ​​to form a first stator magnetic pole assembly. The magnetization directions of adjacent large permanent magnets are opposite, and the magnetization directions of adjacent small permanent magnets are opposite; the angle between the two radial edges of the small permanent magnet is D2, and the radial thickness of the small permanent magnet is H5; the angle between the two radial edges of the large permanent magnet is D3, and the radial thickness of the large permanent magnet is H6; and 1.5<D3 / D2<2.2, 0.4<H6 / H5<0.6. The output torque can be maximized while reducing the amount of magnetic steel.

[0017] (3) The axial projection profile of each first stator permanent magnet is a triangle. The first stator permanent magnet is divided into an angular centripetal permanent magnet and an edge centripetal permanent magnet. The edge centripetal permanent magnet is magnetized radially, and the angular centripetal permanent magnet is magnetized tangentially. The angular centripetal permanent magnet and the edge centripetal permanent magnet are spliced ​​together to form a first stator magnetic pole assembly. The magnetization directions of two adjacent angular centripetal permanent magnets are opposite, and the magnetization directions of two adjacent edge centripetal permanent magnets are opposite. The sides of the angular centripetal permanent magnets constitute the outer side of the first stator magnetic pole assembly, and the sides of the edge centripetal permanent magnets constitute the inner side of the first stator magnetic pole assembly. The adjacent sides of the angular centripetal permanent magnet and the edge centripetal permanent magnet are of equal length and completely aligned. The outer diameter of the first stator is d5, the inner diameter of the first stator is d4, the number of pole pairs of the first stator is p3, and 0.8×d4×sin(360deg / 4p3)<d5-d4<0.9×d4×sin(360deg / 4p3). At this time, the magnetic circuit is optimal, the internal magnetic field effect is best, and the torque density is highest.

[0018] Preferably, the modulation ring includes modulation teeth, and the modulation teeth are made of a material with high saturation magnetic induction intensity. This greatly improves the maximum output torque (i.e. torque density) of the reduction gear when the installation space is fixed, and the torque is transmitted through the magnetic field without friction. There is no mechanical loss, thereby improving the motor operation efficiency and reducing the overall noise of the motor.

[0019] Preferably, the modulation ring comprises a cage, the cage comprises two end plates and a plurality of connecting rods connected between the two end plates, the connecting rods extend axially and are distributed along the circumference, and the modulation teeth are fixed in the gaps between adjacent connecting rods, thereby ensuring the overall strength of the modulation ring.

[0020] Preferably, each modulation tooth has the same size, the total number of modulation teeth is p2, the axial projection profile of the modulation tooth is fan-shaped, the angle between the two radial edges of the modulation tooth is D1, and D1 / (360deg / p2)=0.5-0.6; the radial thickness of the modulation tooth is H2, the circumferential average width of the modulation tooth is W2, and H2 / W2=0.55-1.3, so as to achieve the best modulation effect.

[0021] Preferably, the connecting rod is cylindrical, and arc grooves are provided in the middle of the two circumferential sides of the modulation teeth, and the arc grooves fit the surface of the connecting rod so that the connecting rod and the cylindrical shape support each other, while the modulation effect is not affected and the overall structural strength of the modulation ring after installation is increased.

[0022] Preferably, the number of first rotor pole pairs is p1, the total number of modulation teeth is p2, the number of first stator pole pairs is p3, and p1=|p2-p3|.

[0023] Preferably, the first stator is fixed to the casing, and a shielding ring is embedded in the inner wall of the casing to reduce magnetic leakage to the outside of the casing. The first rotor has too strong outward magnetic field collection ability, which will generate large eddy current losses in the casing. When the shielding ring is embedded in the inner wall of the casing, the thickness of the casing can be reduced, which ensures the overall strength of the casing and allows the shielding ring to shield the magnetic field, thereby effectively reducing the eddy current of the casing.

[0024] Preferably, the following formula relationship exists among the thickness H4 of the shielding ring, the outer diameter d1 of the first rotor, the inner diameter d5 of the shielding ring, and the number of first rotor pole pairs p1:

[0025] d5-d1<d1×sin(360deg / 4p1), H4≥0.185×d1×(1+sin(360deg / 4p1))-0.5×d5. Therefore, it is ensured that the shielding ring effectively shields the magnetic field and reduces the eddy current loss.

[0026] If d5-d1>d1×sin(360deg / 4p1), a shielding ring is not required.

[0027] Preferably, the shielding ring is evenly divided into N sections in the axial direction, the axial length of each shielding ring is L1, the axial length of the first stator magnetic pole assembly is L, all shielding rings are evenly distributed in the axial direction, the shielding rings at the ends are aligned with the first stator magnetic pole assembly, the distance between the end faces of each two shielding rings is (LN*L1) / (N-1), and L1>0.65*(L / N), N<10. In this way, the weight of the shielding ring can be further reduced, and the torque loss caused by the magnetic shielding effect can be reduced to a certain extent.

[0028] In order to achieve the above-mentioned object, the bicycle mid-mounted reduction motor of the utility model is characterized by comprising:

[0029] chassis;

[0030] A torque assembly, which runs through the housing and has two ends extending out of the housing to receive external torque (such as the torque generated by pedaling when riding);

[0031] The motor part includes a second stator and a second rotor, the second stator includes an iron core attached to the housing and a winding wound on the iron core, the winding generates a rotating magnetic field when energized, and the second rotor includes a second rotor, the second rotor is used to provide a permanent magnetic field matching the electromagnetic field generated by the stator winding, the second rotor is located inside the second stator and coaxial with the second stator, and a third air gap is maintained between the second rotor and the second stator;

[0032] In the magnetic transmission speed reducer of the utility model, the first rotor is driven by the second rotor to rotate synchronously;

[0033] A two-way clutch is arranged between the torque assembly and the modulation ring for selectively transmitting torque to it by the torque assembly or by the magnetic transmission reduction device. The two-way clutch has a cylindrical output shaft extending out of the housing for outputting torque, and the cylindrical output shaft is sleeved on the radial outer side of one end of the torque assembly.

[0034] The power-assisted bicycle has a central motor, the permanent magnetic field of the second rotor is coupled with the rotating magnetic field generated by the second stator to generate an effective torque, the first rotor is driven by the second rotor to rotate synchronously, and the power of the motor part is transmitted to the reduction device, which is output by the modulation ring. The motor part and the magnetic transmission reduction device both use magnetic force to achieve transmission, which greatly improves the field strength of the space where the modulation ring part is located, and greatly improves the maximum output torque (i.e. torque density) of the reduction device when the installation space size is fixed, thereby improving the motor operation efficiency and reducing the overall noise of the motor.

[0035] Preferably, the mid-mounted reduction motor includes a sensor and a controller, and the controller instructs the motor part to work according to the torque signal provided by the sensor. Accordingly, when the mid-mounted reduction motor is installed on the bicycle, the motor part is instructed to work through the pedaling action to drive the power assist, and the bicycle moves forward.

[0036] Preferably, a fixed inner shell is arranged outside the torque assembly, and a sensor is arranged in the inner shell for detecting the torque signal and receiving the pedal driving torque. Specifically, the pedal driving torque can be a pressure signal or the rotation speed of the torque assembly.

[0037] Preferably, the two-way clutch comprises an inner sleeve, an outer sleeve, a plurality of first clutches and a plurality of second clutches, the inner sleeve is arranged in the torque assembly and rotates together with the torque assembly, the outer sleeve is arranged in the modulation ring and rotates together with the modulation ring, the cylindrical output shaft is sleeved on the radial outer side of the inner sleeve, the outer sleeve is sleeved on the radial outer side of the cylindrical output shaft, a plurality of first clutches are distributed between the cylindrical output shaft and the inner sleeve, and a plurality of second clutches are distributed between the cylindrical output shaft and the outer sleeve; the first clutch and the second clutch are arranged in reverse. Accordingly, the torque transmission between the first outer peripheral surface and the first inner peripheral surface through the first clutch and the torque transmission between the second inner peripheral surface and the second outer peripheral surface through the second clutch can only be selected to work, and when one of the first clutch and the second clutch transmits torque, the other does not transmit torque. Make the mid-mounted reduction motor suitable for various movement forms of the bicycle: First, when the bicycle starts to move forward normally from a stationary state, the pedaling action is allowed to drive the bicycle alone without being hindered by the mid-mounted reduction motor. At this time, the mid-mounted reduction motor is not powered and does not work. Second, by supplying power to the mid-mounted reduction motor, the mid-mounted reduction motor is allowed to output power alone to drive the bicycle without being hindered by the torque component, and the pedaling action can be stopped at this time. Third, when the sensor detects the pedaling action, it provides an electrical signal to the controller. The controller can achieve different sizes of rotational torque by controlling the size of the winding current to drive its second rotor. The motor and the pedaling force provide power at the same time. At this time, the torque provided by the motor is determined by the pedaling force and the pedaling frequency.

[0038] In order to facilitate assembly with other parts, the torque assembly includes a motor shaft and a torque sleeve sleeved on the motor shaft and rotating with the motor shaft. This can simplify the processing of the torque assembly, and different materials can be selected to make the motor shaft and the torque sleeve based on structural requirements. Based on this, it is easy to think that the torque assembly can be embodied as a component under the condition that the processing technology can be realized.

[0039] Preferably, the second rotor includes a second rotor core and main magnetic steel and auxiliary magnetic steel arranged at intervals on the circumference of the second rotor core, the main magnetic steel is magnetized tangentially, the auxiliary magnetic steel is magnetized radially, and the second rotor core has an interval magnetic bridge located between the main magnetic steel and the auxiliary magnetic steel for isolating the main magnetic steel and the auxiliary magnetic steel. The interval magnetic bridge can achieve the effect of focusing magnetic flux to the air gap, effectively improve the output torque, and at the same time can save more magnetic steel than the conventional Halbach array, and facilitate the manufacture of the rotor.

[0040] Preferably, the second rotor core has an inner rotor magnetic bridge located on the inner circumference of the main magnetic steel and the auxiliary magnetic steel.

[0041] Preferably, the main magnetic steel and the auxiliary magnetic steel are embedded in the second rotor core, thereby increasing the convenience of assembly and ensuring the structural strength of the second rotor.

[0042] Preferably, two boots are extended from the two vertex positions of the second rotor core corresponding to the main magnetic steel near the third air gap side to form a semi-open main magnetic steel installation slot. On the one hand, it is convenient to install the main magnetic steel. On the other hand, the magnetic circuit closed loop of the main magnetic steel near the third air gap is reduced to reduce magnetic leakage. Furthermore, when the magnetic lines of force extend from the auxiliary magnetic steel to the third air gap, they are more evenly diffused from the rotor boots in the third air gap, and cooperate with the stator slots to effectively reduce torque fluctuations.

[0043] In one embodiment, the axial projection profile of the main magnetic steel is rectangular, the axial projection profile of the auxiliary magnetic steel is fan-shaped, the auxiliary magnetic steel is located radially inward, the width of the main magnetic steel is w1, the radial length of the main magnetic steel is h1, the inner width of the auxiliary magnetic steel is w5, the radial length of the auxiliary magnetic steel is h2, and the width of the magnetic bridge between the main magnetic steel and the auxiliary magnetic steel is w2. The conditions 1.2<w1 / w5<2.2, 1.5

[0044] In one embodiment, the axial projection profile of the main magnetic steel is a rectangle, the axial projection profile of the auxiliary magnetic steel is a rectangle, and the auxiliary magnetic steel is located radially inward. Accordingly, the magnetic force lines that are self-closed in the inner part of the main magnetic steel can be pulled back to the main magnetic circuit to reduce magnetic leakage, so that the magnetic force at the third air gap is stronger and the output torque is greater.

[0045] In one embodiment, the axial projection profile of the main magnetic steel is rectangular, the axial projection profile of the auxiliary magnetic steel is fan-shaped, and the radial length of the auxiliary magnetic steel is equal to the radial length of the main magnetic steel. The iron core of the auxiliary magnetic steel radially outside extends two boots at two vertex positions on the air gap side of the main magnetic steel to form a semi-open main magnetic steel installation slot.

[0046] Preferably, the material grade of the main magnetic steel is higher than that of the auxiliary magnetic steel. Maximize the utilization rate of the permanent magnetic force of the rotor and reduce cost waste. Due to the limitation of the magnetic saturation upper limit of the magnetic conductive material used in the motor, the main permanent magnetic field at the air gap is provided by the main magnetic steel, and the auxiliary magnetic steel plays a role in enhancing the field strength at the air gap. At the same time, through reasonable position placement and magnetization direction setting, the magnetic lines of force of the main magnetic steel away from the air gap end are twisted to reduce the leakage of the main magnetic steel. The main magnetic flux is provided by the main magnetic steel.

[0047] ​Preferably, uniformly distributed and equal-width stator teeth are formed on the second stator core, winding slots are formed between adjacent stator teeth, and the winding slots have stator slots facing the third air gap; the number of pole pairs of the winding generating the magnetic field is P1, the number of stator teeth is P2, the number of second rotor pole pairs is P3, and P1+P3=P2. Furthermore, a stator boot extending toward the stator slot is provided near the third air gap on the stator teeth. The equal-width stator teeth serve as both the stator magnetic circuit and the magnetic field of the second rotor, which not only facilitates winding, but also cooperates with the opening of the main magnetic steel to adjust the torque wave.

[0048] Preferably, the first rotor and the second rotor are configured on the same cylindrical rotor shaft, and the cylindrical rotor shaft sleeve is radially outside the torque assembly, thereby simplifying the structure of the first rotor and the second rotor and increasing the concentricity of the first rotor and the second rotor.

[0049] In one embodiment, the motor part is coaxially connected in series with the magnetic transmission reduction device, thereby reducing the radial size of the entire mid-mounted reduction motor.

[0050] In one embodiment, the motor part partially overlaps with the magnetic transmission reduction device in the axial direction, and the motor part is placed inside the reduction device, thereby reducing the axial size of the entire mid-mounted reduction motor.

[0051] In one embodiment, the motor part overlaps with the magnetic transmission reduction device in the axial direction, and the motor is entirely placed inside the reduction device, thereby minimizing the axial size of the entire mid-mounted reduction motor.

[0052] The utility model realizes deceleration through magnetic transmission. When the central reduction motor is working, the second rotor rotates by means of the magnetic flux generated by the second stator, and the first rotor is driven by the second rotor to rotate synchronously, and the power of the motor part is transmitted to the reduction device, which is decelerated and output by the reduction device. Both the motor part and the reduction device use magnetic force to realize transmission, which greatly improves the field strength of the space where the modulation ring part is located, and greatly improves the maximum output torque of the reduction device when the installation space size is fixed, thereby improving the motor operation efficiency and reducing the overall noise of the motor.

[0053] The central reduction motor of the utility model realizes reduction in speed by means of magnetic transmission, so that the volume of the central motor can be reduced, the rotation efficiency can be improved, and the noise during operation can be reduced and the service life can be extended while ensuring the reduction ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is an orthographic projection schematic diagram of a mid-mounted motor of an electric power-assisted bicycle according to Embodiment 1 of the present utility model from one viewing angle;

[0055] Figure 2 for Figure 1 AA section view;

[0056] Figure 3 for Figure 1 BB section view;

[0057] Figure 4 for Figure 1 CC section view;

[0058] Figure 5 for Figure 1 The schematic diagram of the structural breakdown of the mid-mounted motor shown;

[0059] Figure 6 for Figure 1-4 A partially enlarged schematic cross-sectional view of a reduction gear device of a mid-mounted motor is shown in FIG.

[0060] Figure 7 for Figure 6 A schematic diagram of a first rotor pole assembly in FIG.

[0061] Figure 8 for Figure 6 Schematic diagram of the modulation loop;

[0062] Fig. 9 for Figure 6 A schematic diagram of a first stator pole assembly in;

[0063] Fig.10 for Figure 6 Schematic diagram of the shielding ring;

[0064] Fig.11 for Figure 5 A schematic diagram of the structural decomposition of the first housing and the first stator shown in ;

[0065] Fig.12 It is a partial schematic diagram of a cross section of a first structure of a first stator magnetic pole assembly of the utility model;

[0066] Fig.13 for Fig.12 A schematic diagram of the magnetization direction of the first stator permanent magnet constituting the first stator magnetic pole assembly;

[0067] Fig.14 is a partial schematic diagram of a cross section of a second structure of a first stator pole assembly;

[0068] Fig.15 for Fig.14 A schematic diagram of the magnetization direction of the first stator permanent magnet constituting the first stator magnetic pole assembly;

[0069] Fig.16 is a partial schematic diagram of a cross section of a third structure of the first stator pole assembly;

[0070] Fig.17 for Fig.16 A schematic diagram of the magnetization direction of the first stator permanent magnet constituting the first stator magnetic pole assembly;

[0071] Fig.18 for Figure 5 A schematic diagram of the structure in which the first rotor and the second rotor are co-arranged on the same cylindrical rotor shaft;

[0072] Fig.19 for Figure 5 , a schematic diagram of an orthographic projection of a first rotor and a second rotor being co-arranged on the same cylindrical rotor shaft from one viewing angle;

[0073] Fig. 20 for Fig.19 DD section view;

[0074] Fig.21 for Fig. 20 EE section enlarged view;

[0075] Fig. 22 A partial schematic diagram of another structure of the second rotor is shown, and the magnetization directions of the main magnetic steel and the auxiliary magnetic steel are illustrated;

[0076] Fig.23 is a partial schematic diagram showing a third structure of the second rotor;

[0077] Fig.24 for Fig.18 Schematic diagram of the structural decomposition of the second rotor;

[0078] Fig.25 for Fig. 20 FF section view;

[0079] Fig.26 is a schematic diagram of the magnetization direction of the first rotor permanent magnet;

[0080] Fig. 27 for Figure 2 A partial schematic diagram of the second stator core;

[0081] Fig.28 This is another structural schematic diagram of the second stator core of the utility model;

[0082] Fig.29 for Figure 5 An axial orthographic projection diagram of the modulation ring shown in ;

[0083] Fig.30 for Fig.29 GG section view;

[0084] Fig.31 for Fig.30 HH sectional view;

[0085] Fig.32 A partial schematic diagram of another cross-sectional structure of a modulation ring;

[0086] Fig.33 for Figure 5 Schematic diagram of the structural decomposition of the modulation ring shown in;

[0087] Fig.34 A schematic diagram of a two-way clutch of the utility model;

[0088] Fig.35 for Fig.34 a schematic orthographic projection of one view of the structure shown;

[0089] Fig.36 for Fig.35 A partial enlarged view of the JJ section;

[0090] Fig.37 for Fig.36 KK sectional view;

[0091] Fig.38 This is a schematic cross-sectional structure diagram of a mid-mounted motor for an electric power-assisted bicycle according to Embodiment 2 of the present utility model;

[0092] Fig.39 This is a schematic cross-sectional structure diagram of a mid-mounted motor for an electric power-assisted bicycle according to Embodiment 3 of the present utility model;

[0093] Fig.40 This is a schematic diagram of the position of the mid-mounted motor of the power-assisted bicycle of the utility model on the bicycle;

[0094] Fig.41 It is a schematic diagram of the assembly structure of the mid-mounted motor of the power-assisted bicycle and the frame of the bicycle;

[0095] Description of the numbers in the figure:

[0096] 100 housing, 101 first housing, 102 second housing, 103 first end cover, 104 second end cover, 105 shielding ring, 106 inner housing, 107 first bearing, 108 second bearing, 109 third bearing, 110 fourth bearing, 111 fifth bearing; shielding ring thickness H4, shielding ring inner diameter d5;

[0097] 200 torque assembly, 201 motor shaft, 202 torque sleeve;

[0098] 300 motor part,

[0099] 310 second stator, 311 second stator core, 312 winding, 313 stator tooth, 314 winding slot, 315 stator notch, 316 stator boot,

[0100] 320 second rotor, 321 second rotor magnetic pole assembly, 322 main magnetic steel, 323 auxiliary magnetic steel, 324 interval magnetic bridge, 325 rotor inner magnetic bridge, 326 second rotor core, 327 opening, 328 rotor shoe,

[0101] The width of the main magnet is w1, the radial length of the main magnet is h1, the inner width of the auxiliary magnet is w5, the radial length of the auxiliary magnet is h2, and the width of the magnetic bridge between the main magnet and the auxiliary magnet is w2;

[0102] 330 third air gap;

[0103] 400 magnetic transmission reduction device;

[0104] 410 first stator, 411 first stator magnetic pole assembly, 412 radial permanent magnet, 413 tangential permanent magnet, 414 large-size permanent magnet, 415 small-size permanent magnet, 416 angular centripetal permanent magnet, 417 edge-centripetal permanent magnet,

[0105] The radial thickness of the first stator permanent magnet is H3, the circumferential average width of the first stator permanent magnet is W3, the angle between the two radial edges of the small-sized permanent magnet is D2, and the radial thickness of the small-sized permanent magnet is H5; the angle between the two radial edges of the large-sized permanent magnet is D3, and the radial thickness of the large-sized permanent magnet is H6; the outer diameter of the first stator is d5, the inner diameter of the first stator is d4,

[0106] 420 a first rotor, 421 a first rotor magnetic pole assembly, 422 a first rotor permanent magnet,

[0107] The radial thickness of the first rotor permanent magnet is H1, the circumferential average width of the first rotor permanent magnet is W1, and the outer diameter of the first rotor is d1.

[0108] 430 modulation ring, 431 squirrel cage, 432 end plate, 433 connecting rod, 434 arc groove, 435 modulation tooth,

[0109] The angle between the two radial sides of the modulation tooth is D1, the radial thickness of the modulation tooth is H2, and the average circumferential width of the modulation tooth is W2.

[0110] 440 first air gap,

[0111] 450 second air gap;

[0112] 500 two-way clutch, 501 cylindrical output shaft, 502 inner sleeve, 503 outer sleeve, 504 first clutch member, 505 second clutch member;

[0113] 601 sensor, 602 controller;

[0114] 700 cylindrical rotor shaft;

[0115] 800 power-assisted bicycle, 801 frame, 802 crank, 803 pedal, 804 driving sprocket, 805 driving sprocket locking nut, 806 chain, 807 driving wheel, 808 driven sprocket;

[0116] 900 power-assisted bicycle with mid-mounted motor. DETAILED DESCRIPTION

[0117] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0118] The terms "including" and "having" and any variations thereof in the specification and claims of the present utility model are intended to cover non-exclusive inclusions. For example, a method or product comprising a series of technical features is not necessarily limited to those technical features clearly listed, but may also include other technical features that are not clearly listed and can be included in the method or product.

[0119] In the description of the present utility model, it is necessary to understand that the technical features defined by the terms "first", "second", "third" and the like with sequential concepts are only for the purpose of clearly describing the defined technical features so that the defined technical features can be clearly distinguished from other technical features, but do not represent such naming in actual implementation, and therefore cannot be understood as a limitation of the present utility model.

[0120] The present invention is described in detail below in conjunction with specific embodiments and drawings.

[0121] Power-assisted bicycles are well known, and they drive the bicycle forward by transmitting torque to the wheels through the rider's pedals. Equipping a bicycle with a mid-mounted motor can provide external power without affecting pedaling, which can save the rider more effort. Compared with a hub motor, the hub motor will generate resistance to the vehicle when the vehicle slides forward because the hub motor is coaxial with the wheel and transmits power directly to the wheel. The mid-mounted motor is installed in the middle of the frame and transmits power to the wheel through a transmission mechanism, so that the bicycle is basically not subject to resistance from the mid-mounted motor when sliding forward, allowing the bicycle to slide a longer distance.

[0122] Each embodiment of the utility model provides such a mid-mounted motor for a power-assisted bicycle.

[0123] Example 1

[0124] like Figure 1-5 The mid-mounted motor of the power-assisted bicycle of this embodiment is shown, which includes: a housing 100 , a torque assembly 200 , a motor part 300 , a magnetic transmission reduction device 400 , a two-way clutch 500 , a sensor 601 and a controller 602 .

[0125] The housing 100 is used as a base for assembling the torque assembly, the motor part, the magnetic transmission speed reducer, and the two-way clutch, and is also used to assemble the mid-mounted speed reducer motor on the bicycle. Figure 5 The housing 100 shown includes a first shell 101, a second shell 102 and a first end cover 103 assembled together by fasteners.

[0126] The torque assembly 200 passes through the housing 100 and its two ends extend out of the housing to receive external torque, such as the torque generated by pedaling when riding. In this embodiment, the torque assembly 200 includes a motor shaft 201 and a torque sleeve 202. The torque sleeve 202 is sleeved on the motor shaft and assembled with the motor shaft by splines so that the torque sleeve rotates with the motor shaft. A fixed inner shell 106 is configured on the outer side of the torque assembly, and one end of the inner shell 106 is fixed to the second end cover 104, so that the torque assembly can rotate relative to the inner shell.

[0127] The motor part 300 is Figure 4 The motor part 300 is enclosed by a double-dot chain line, and includes a second stator 310 and a second rotor 320. The second rotor 302 is located inside the second stator 310 and is coaxial with the second stator. A third air gap 330 is maintained between the second rotor 320 and the second stator 310. In particular, the axial height of the second rotor permanent magnet is consistent with the axial thickness of the second stator core, which can ensure that the axial size of the product is compact.

[0128] The second stator 310 includes a second stator core 211 attached to the second housing 102 of the casing and a winding 312 wound around the second stator core. Fig. 27 , Fig.28 As shown, uniformly distributed and equal-width stator teeth 313 are formed on the second stator core 311, winding slots 314 are formed between adjacent stator teeth, and the winding slots 314 have stator slots 315 facing the third air gap. The number of pole pairs generated by the winding is P1, the number of stator teeth is P2, the number of second rotor pole pairs is P3, and P1+P3=P2. Stator teeth 313 are provided with stator boots 316 extending toward the stator slots near the third air gap.

[0129] Applying an alternating signal to the winding 312 can generate a changing magnetic field for driving the second rotor to rotate.

[0130] like Figure 18-24As shown, the second rotor 320 includes an annular second rotor magnetic pole assembly 321, which is used to provide a second rotor magnetic field that rotates with the second rotor. The second rotor magnetic pole assembly 321 includes a main magnetic steel 322 and an auxiliary magnetic steel 323 that are spaced apart and arranged on the circumference of the second rotor core. The main magnetic steel is magnetized tangentially, and the auxiliary magnetic steel is magnetized radially. The magnetization direction is Fig. 22 , Fig.23 Indicated by arrows. The second rotor core 326 has a spacing magnetic bridge 324 located between the main magnetic steel 322 and the auxiliary magnetic steel 323 for isolating the main magnetic steel from the auxiliary magnetic steel. The second rotor core 326 has a rotor inner magnetic bridge 325 located on the inner circumference of the main magnetic steel and the auxiliary magnetic steel. In addition, the spacing magnetic bridge 324 and the rotor inner magnetic bridge 325 are formed on the second rotor core 326, and the main magnetic steel 322 and the auxiliary magnetic steel 323 are embedded in the second rotor core 326. The second rotor core 326 is provided with an opening 327 corresponding to the position of the main magnetic steel 322 close to the third air gap 330, and two opposite rotor boots 328 are formed at the two edges of the opening. In addition, the material grade of the main magnetic steel is higher than that of the auxiliary magnetic steel.

[0131] like Fig.21 As shown, the axial projection profile of the main magnetic steel 322 is a rectangle, and the axial projection profile of the auxiliary magnetic steel 323 is a sector. The auxiliary magnetic steel 323 is located radially inward and is adjacent to the rotor internal magnetic bridge 325 together with the main magnetic steel 322. The rotor internal magnetic bridge 325 is embodied as a circular ring with uniform thickness. The width of the main magnetic steel is w1, the radial length of the main magnetic steel is h1, the inner width of the auxiliary magnetic steel is w5, the radial length of the auxiliary magnetic steel is h2, and the width w2 of the magnetic bridge between the main magnetic steel and the auxiliary magnetic steel meet the conditions 1.2<w1 / w5<2.2, 1.5 Fig. 22 As shown, the axial projection profile of the main magnetic steel 322 is a rectangle, the axial projection profile of the auxiliary magnetic steel 323 is a rectangle, the auxiliary magnetic steel is located radially inward and is adjacent to the rotor inner magnetic bridge together with the main magnetic steel, and the rotor inner magnetic bridge is embodied as a circular ring with uniform thickness. Fig.23 As shown, the axial projection profile of the main magnetic steel 322 is rectangular, the axial projection profile of the auxiliary magnetic steel 323 is fan-shaped, and the radial length of the auxiliary magnetic steel is equal to the radial length of the main magnetic steel.

[0132] like Figure 6 As shown, the magnetic transmission reduction device 400 includes a first stator 410 , a first rotor 420 and a modulation ring 430 .

[0133] like Fig.11 ​As shown, the first stator 410 is fixed in the first shell 101 of the housing, and the inner wall of the first shell 101 is embedded with a steel ring as a shielding ring 105 to shield the magnetic field of the first rotor. The first stator 410 includes an annular first stator magnetic pole assembly 411, and the first stator magnetic pole assembly is used to provide a fixed first stator magnetic field. Figure 12-17 As shown, the magnetic field of the first stator pole assembly 411 is distributed according to the Halbach Array. The first stator pole assembly 411 is formed by magnetizing the first stator permanent magnet in blocks and splicing them together. The single pole is divided into two blocks, which are radially magnetized and tangentially magnetized respectively, and the whole is magnetically concentrated inward. Moreover, the shielding ring is evenly divided into N sections in the axial direction, and the axial length of each shielding ring is L1. The axial length of the first stator pole assembly is L. All shielding rings are evenly distributed in the axial direction, and the shielding rings at the ends are aligned with the first stator pole assembly. The distance between the end faces of each two shielding rings is (LN*L1) / (N-1), and L1>0.65*(L / N), N<10.

[0134] The first stator permanent magnet is configured in any of the following ways:

[0135] (1) Figure 12-13 As shown, the axial projection profiles of each first stator permanent magnet are all fan-shaped and of the same size. The first stator permanent magnet is divided into radial permanent magnets 412 and tangential permanent magnets 413. The radial permanent magnets are magnetized radially, and the tangential permanent magnets are magnetized tangentially. The arrows in the figure indicate the magnetization direction. The radial permanent magnets and the tangential permanent magnets are spliced ​​at intervals to form the first stator magnetic pole assembly. The magnetization directions of two adjacent radial permanent magnets are opposite, and the magnetization directions of two adjacent tangential permanent magnets are opposite; the radial thickness of the first stator permanent magnet is H3, the circumferential average width of the first stator permanent magnet is W3, and W3 / H3=0.52-0.6; the circumferential average width of the first stator permanent magnet is the chord length width confirmed by the circle where the geometric center of the axial projection profile of the first stator permanent magnet is located;

[0136] (2) Figure 14-15 As shown, the axial projection profile of each first stator permanent magnet is fan-shaped. The first stator permanent magnet is divided into a large permanent magnet 414 and a small permanent magnet 415. The large permanent magnet is magnetized radially, and the small permanent magnet is magnetized tangentially. The arrows in the figure indicate the magnetization direction. The large permanent magnets and the small permanent magnets are spliced ​​into the first stator magnetic pole assembly at intervals. The magnetization directions of adjacent large permanent magnets are opposite, and the magnetization directions of adjacent small permanent magnets are opposite; the angle between the two radial edges of the small permanent magnet is D2, and the radial thickness of the small permanent magnet is H5; the angle between the two radial edges of the large permanent magnet is D3, and the radial thickness of the large permanent magnet is H6; and 1.5<D3 / D2<2.2, 0.4<H6 / H5<0.6;

[0137] (3) Figure 16-17As shown, the axial projection profile of each first stator permanent magnet is a triangle. The first stator permanent magnets are divided into angular centripetal permanent magnets 416 and edge centripetal permanent magnets 417. The edge centripetal permanent magnets are magnetized radially and the angular centripetal permanent magnets are magnetized tangentially. The arrows in the figure indicate the magnetization direction. The angular centripetal permanent magnets and the side centripetal permanent magnets are spliced ​​at intervals to form a first stator magnetic pole assembly, the magnetizing directions of two adjacent angular centripetal permanent magnets are opposite, the magnetizing directions of two adjacent side centripetal permanent magnets are opposite, the sides of the angular centripetal permanent magnets constitute the outer side of the first stator magnetic pole assembly, the sides of the side centripetal permanent magnets constitute the inner side of the first stator magnetic pole assembly, the adjacent sides of the angular centripetal permanent magnets and the side centripetal permanent magnets are of equal length and completely aligned; the outer diameter of the first stator is d5, the inner diameter of the first stator is d4, the number of pole pairs of the first stator is p3, and 0.8×d4×sin(360deg / 4p3)<d5-d4<0.9×d4×sin(360deg / 4p3).

[0138] like Figure 5 , Figure 18-20 , Figure 25-26 As shown, the first rotor 420 includes a first rotor pole assembly 421, which is used to provide a first rotor magnetic field that rotates with the first rotor. The first rotor 420 is located on the inner side of the first stator 410 and is coaxial with the first stator. The magnetic field of the first rotor pole assembly 421 is distributed according to the Halbach Array. The first rotor pole assembly is formed by magnetizing the first rotor permanent magnet 422 in blocks and splicing them together. A single pole is divided into four blocks, and the whole is magnetized outward. The number of pole pairs of the first rotor is p1, and the first rotor contains 8×p1 first rotor permanent magnets. The magnetization directions of two adjacent first rotor permanent magnets differ by (45-360 / (8×p1)) degrees. Fig.26 The arrows in the figure indicate the magnetizing direction of the adjacent first rotor permanent magnets. The magnetizing direction changes its angle one by one in one direction (such as clockwise or counterclockwise) on the axial projection plane, so that the magnetic pole directions of adjacent single poles are opposite. Fig.26 When the four adjacent first rotor permanent magnets form a single pole, the magnetic pole directions of the two adjacent single poles are opposite. Figure 7 As shown, the axial projection profile of the first rotor permanent magnet is fan-shaped, and the sizes of the first rotor permanent magnets are the same, with a radial thickness of H1 and an average circumferential width of W1, where H1 / W1=0.8-1.5. The average circumferential width of the first rotor permanent magnet is the chord length width confirmed by the circle where the geometric center of the axial projection profile of the first rotor permanent magnet is located.

[0139] In the illustrated structure, the first rotor 420 and the second rotor 320 are co-arranged on the same cylindrical rotor shaft 700, and the first rotor is rotated synchronously with the second rotor.

[0140] Furthermore, the shielding ring 105 has a thickness H4 (see Fig.10), the first rotor outer diameter d1 (see Fig.25 ), shielding ring inner diameter d5 (see Fig.10 ), there is the following formula relationship between the number of first rotor pole pairs p1: d5-d1<d1×sin(360deg / 4p1), H4≥0.185×d1×(1+sin(360deg / 4p1))-0.5×d5.

[0141] The modulation ring 430 is located between the first rotor 420 and the first stator 410 . The modulation ring 430 is coaxial with the first rotor 420 and the first stator 410 . A first air gap 440 is maintained between the modulation ring and the first stator, and a second air gap 450 is maintained between the modulation ring and the first rotor.

[0142] like Figure 5 , Figure 29-Figure 33 As shown, the modulation ring 430 includes a modulation tooth 435 and a cage 431. The modulation tooth 431 is made of a high saturation magnetic induction material such as 1J22 iron-cobalt-vanadium soft magnetic alloy or DT4 electromagnetic pure iron.

[0143] The cage 431 includes two end plates 432 and a plurality of connecting rods 433 connected between the two end plates. The connecting rods extend axially and are distributed along the circumference. The modulation teeth 435 are fixed in the gaps between adjacent connecting rods 433. The modulation teeth 435 are fixed in the gaps between adjacent connecting rods 433. The modulation teeth 435 can be embedded in the gaps between adjacent connecting rods 433, or the modulation ring can be completed by injection molding. The cage is a composite material. The cage end plates and the modulation teeth are placed in a mold for integral injection molding, thereby ensuring the size requirements and strength requirements of the modulation teeth, the cage and the cage end plates.

[0144] Moreover, each modulation tooth has the same size, the total number of modulation teeth is p2, the axial projection profile of the modulation teeth is fan-shaped, the angle between the two radial edges of the modulation teeth is D1, and D1 / (360deg / p2)=0.5-0.6; the radial thickness of the modulation tooth is H2, the circumferential average width of the modulation tooth is W2, and H2 / W2=0.55-1.3. Among them, the circumferential average width of the modulation tooth is the chord length width confirmed by the circle where the geometric center of the axial projection profile of the modulation tooth is located. In another embodiment, alternatively, the connecting rod 433 is cylindrical, and an arc groove 434 is opened in the middle position of the two circumferential sides of the modulation tooth 435, and the arc groove 434 fits the surface of the connecting rod so that the connecting rod and the cylindrical shape support each other.

[0145] Further, the number of first rotor pole pairs is p1, the total number of modulation teeth is p2, the number of first stator pole pairs is p3, and p1=|p2-p3|.

[0146] Among them, the first stator and the first rotor are configured with different pole pairs, and the modulation ring modulates the magnetic field of the first rotor's magnetomotive force, so that the magnetic field of the first air gap is coupled with the magnetic field of the second air gap, and the rotation from the first rotor is decelerated through the modulation ring and output coaxially with the first rotor to increase the torque.

[0147] like Figure 4-5 , Figure 34-37 As shown, the bidirectional clutch 500 is arranged between the torque assembly 200 and the modulation ring 430. For alternative, the torque assembly transmits torque to it or the modulation ring transmits torque to it, and the bidirectional clutch has a cylindrical output shaft 501 extending out of the housing for outputting torque. The bidirectional clutch 500 includes an inner sleeve 502, an outer sleeve 503, a plurality of first clutch members 504 and a plurality of second clutch members 505. The inner sleeve 502 is configured on the torque assembly 200 through spline matching and rotates with the torque assembly. The outer sleeve 503 is fixedly configured on the modulation ring by die-casting with one end face of the modulation ring and rotates with the modulation ring. The cylindrical output shaft 501 is sleeved on the radial outer side of the inner sleeve 502, and the outer sleeve 503 is sleeved on the radial outer side of the cylindrical output shaft 501. The plurality of first clutch members 504 are distributed between the cylindrical output shaft 501 and the inner sleeve 502, and the plurality of second clutch members 505 are distributed between the cylindrical output shaft 501 and the outer sleeve 503. The first clutch member 504 and the second clutch member 505 are arranged in opposite directions. In order to make the first clutch and the second clutch evenly distributed on the circumference to make the two-way clutch sensitive, adjacent first clutches are separated by rollers in the circumferential direction and fill the circumferential gap between the cylindrical output shaft and the inner sleeve together with the rollers, and adjacent second clutches are separated by rollers in the circumferential direction and fill the circumferential gap between the cylindrical output shaft and the outer sleeve together with the rollers. In the illustrated structure, the first clutch and the second clutch have the same cross-sectional structure, and the first clutch and the second clutch are arranged in reverse, which means that their installation directions are opposite.

[0148] exist Figure 4 In the embodiment, the first clutch 504 and the second clutch 505 are located at different positions in the axial direction, and the first clutch and the second clutch are misaligned in the axial direction. Figure 35-37 In the embodiment, the first clutch member 504 and the second clutch member 505 are located at the same position in the axial direction and correspond to each other in the radial direction. Any structure can be selected according to the requirements.

[0149] As described above, a first bearing 107 is assembled between the pivot 201 and the second end cover 104 of the second shell, a second bearing 108 is assembled between the pivot 201 and the cylindrical output shaft 501 of the two-way clutch, a third bearing 109 is assembled between the cylindrical rotor shaft 700 and the second end cover 104 of the second shell, a fourth bearing 110 is assembled between the cylindrical rotor shaft 700 and the cylindrical output shaft 501 of the two-way clutch, and a fifth bearing 111 is assembled between the cylindrical rotor shaft 700 and the first end cover 103, so that the torque assembly 200, the first rotor 420 and the second rotor 320 can all rotate relative to the casing 100, and the cylindrical output shaft 501 of the two-way clutch can rotate relative to the torque assembly and the modulation ring.

[0150] Reference Fig.36 As shown, when the inner sleeve 502 is rotated clockwise by pedaling, the first clutch 504 is subjected to friction and has a tendency to rotate counterclockwise, and the long diameter direction of the first clutch is squeezed between the cylindrical output shaft 501 and the inner sleeve 502. The clockwise rotation of the inner sleeve 502 is transmitted to the cylindrical output shaft 501 by the first clutch in the same direction, causing the cylindrical output shaft 501 to rotate clockwise. Further, when the cylindrical output shaft 501 rotates clockwise, the second clutch 505 is subjected to friction and has a tendency to rotate counterclockwise, and the short diameter direction of the second clutch corresponds to the cylindrical output shaft 501 and the outer sleeve 503. The second clutch 505 will not transmit the clockwise rotation of the cylindrical output shaft to the outer sleeve 503 in the same direction. At this time, the torque of the torque assembly will not be transmitted to the outer sleeve and the modulation ring. This situation is suitable for driving the bicycle forward by pedaling.

[0151] Reference Fig.36 As shown, the mid-mounted motor is started by supplying power to the mid-mounted motor, and the second rotor rotates by means of the magnetic flux generated by the second stator. The first rotor is driven by the second rotor to rotate synchronously, and the power of the motor part is transmitted to the modulation ring of the reduction device. Its outer sleeve is connected to the modulation ring. When its outer sleeve 503 rotates clockwise, the second clutch 505 has a tendency to rotate clockwise due to friction. The long diameter direction of the second clutch 505 is squeezed between the cylindrical output shaft 501 and the outer sleeve 503. The clockwise rotation of the outer sleeve 503 is transmitted to the cylindrical output shaft 501 in the same direction by the second clutch 505, causing the cylindrical output shaft 501 to rotate clockwise. Furthermore, when the cylindrical output shaft 501 rotates clockwise, the first clutch 504 has a tendency to rotate clockwise due to friction, and the short diameter direction of the first clutch 504 corresponds to the cylindrical output shaft 501 and the inner sleeve 502, and the first clutch 504 will not transmit the clockwise rotation of the cylindrical output shaft to the inner sleeve 502 in the same direction. At this time, the torque of the modulation ring will not be transmitted to the torque assembly. This situation is suitable for driving the bicycle forward by the mid-mounted motor.

[0152] When riding a bicycle and the bicycle slides forward, according to the one-way clutch mechanism of the transmission mechanism between the mid-mounted motor and the driving wheel, such as the ratchet pawl mechanism configured in the driving wheel and the driven sprocket, the power transmission between the driving sprocket and the driven sprocket of the mid-mounted motor is cut off, and there is no need to provide pedal power or motor power to the bicycle.

[0153] During the riding of the bicycle, when the bicycle is moved backward by actions such as turning around, the bicycle driving wheel establishes transmission with the cylindrical output shaft through the transmission mechanism. According to the above-mentioned rotation of the cylindrical output shaft in the clockwise direction when the bicycle moves forward, the backward movement of the bicycle driving wheel causes the cylindrical output shaft 501 to rotate counterclockwise. The counterclockwise rotation of the cylindrical output shaft causes the inner sleeve 502 and the torque assembly 200 to rotate counterclockwise through the first clutch 504, and causes the outer sleeve and the modulation ring to rotate counterclockwise through the second clutch 505. At this time, the mid-mounted motor is not powered and is in a non-working state.

[0154] During riding, the bicycle may be driven forward by pedaling and by the mid-mounted motor alternately. To this end, the mid-mounted reduction motor includes a sensor 601 and a controller 602. The controller receives a signal of the pedal driving torque provided by the sensor to instruct the motor part to work. Accordingly, when the mid-mounted reduction motor is installed on the bicycle, the pedal action instructs the motor part to work to drive the power-assisted bicycle forward. Figure 5 As shown, the sensor 601 is arranged on the inner shell 106 to detect the torque component receiving the pedal drive torque. The pedal drive torque can be a pressure signal or the rotation of the torque component. The controller 602 can be arranged on the mid-mounted motor or the vehicle. When the rider wants to ride the bicycle forward, the rider pedals the pedal, and the pedal drive torque generated by the pedaling action is transmitted to the torque component through the crank. The sensor detects the rotation trend of the torque component or the pressure signal or rotation signal generated by the rotation and provides the signal to the controller.

[0155] In this embodiment, the permanent magnets constituting the magnetic pole assemblies of the first stator, the first rotor and the second rotor are all distributed along the circumference on the axial projection surface.

[0156] In this embodiment, the motor part 300 and the magnetic transmission reduction device 400 are coaxially connected in series. Figure 4 It is shown in .

[0157] Example 2

[0158] like Fig.38 As shown, the difference between the embodiment 1 and the embodiment 1 is that the motor part 300 and the reduction gear 400 overlap in the axial direction, and the motor part is placed inside the reduction gear. The rest of the structure is the same as the embodiment 1 and will not be described in detail.

[0159] Example 3

[0160] like Fig.39 As shown, the difference between the embodiment 1 and the embodiment 1 is that the motor part 300 and the reduction gear 400 overlap in the axial direction, and the motor is placed inside the reduction gear. The rest of the structure is the same as the embodiment 1 and will not be described in detail.

[0161] The central motor of the above-mentioned embodiments, such as Fig.41 As shown, the vehicle frame is fastened with fasteners, a crank is mounted at each end of the pivot, a pedal 803 is mounted on each crank, and the driving sprocket 804 is fastened to the cylindrical output shaft 501 of the two-way clutch through a clamping sleeve 805. Fig.40 The chain 806 shown is hung on the active sprocket 804 and the driven sprocket 808 of the driving wheel 807, and the vehicle can be ridden as described above.

[0162] The utility model utilizes typical magnetic force rotation, a modulation ring is placed between the first rotor and the first stator, the three are non-contacting, and power is transmitted by magnetic field coupling. The first rotor has fewer magnetic poles, and the first stator has more magnetic poles. The first stator and the first rotor both adopt the Halbach Array to arrange magnetic steel, and the modulation ring is composed of modulation teeth of high magnetic permeability material and squirrel cages of non-magnetic permeability material arranged in an alternating manner. The first stator gathers magnetic force inwardly, and the first rotor gathers magnetic force outwardly. There is a first air gap between the modulation ring and the first stator, and a second air gap between the modulation ring and the first rotor. The first rotor and the second rotor of the motor part are axially integrated structures. When the motor is running, the second rotor drives the first rotor to rotate. The magnetic fields generated by the first rotor and the first stator are modulated by the modulation ring to generate a series of spatial harmonic magnetic fields in the first air gap and the second air gap, wherein the asynchronous spatial magnetic field with the largest amplitude in the first air gap and the second air gap can match the pole pairs of the first stator and the first rotor, respectively, and a stable output torque is generated on the modulation ring through magnetic field coupling, so as to achieve the effect of deceleration and torque amplification. Due to the frictionless characteristics of magnetic transmission, and the ultra-high torque density brought by the magnetic concentrating structure and high magnetic permeability materials designed in the utility model, the system efficiency is improved and the operating noise is reduced.

Claims

1. Magnetic transmission speed reducer, characterized by It comprises a first stator (410), a first rotor (420) and a modulation ring (430), wherein A first stator (410), comprising a first stator magnetic pole component (411), the first stator magnetic pole component being used to provide a first stator magnetic field; A first rotor (420), comprising a first rotor magnetic pole assembly (421), the first rotor magnetic pole assembly being used to provide a first rotor magnetic field that rotates with the first rotor, the first rotor (420) being located inside the modulation ring (430) and coaxial with the modulation ring; A modulation ring (430) is located between the first rotor and the first stator, the modulation ring is coaxial with the first rotor and the first stator, a first air gap (440) is maintained between the modulation ring and the first stator, and a second air gap (450) is maintained between the modulation ring and the first rotor; The first stator (410) and the first rotor (420) are configured with different pole pairs, so that the magnetic field of the first air gap is coupled with the magnetic field of the second air gap, and the rotation of the first rotor is decelerated and output by the modulation ring.

2. The magnetic transmission reduction device according to claim 1 is characterized in that: The magnetic field of the first stator (410) focuses inwards, and the magnetic field of the first rotor (420) focuses outwards.

3. The magnetic transmission reduction device according to claim 1 or 2, characterized in that: The first rotor magnetic pole assembly is formed by magnetizing the first rotor permanent magnet (422) in blocks and then splicing them together. A single pole is divided into four blocks, and the whole body gathers magnetic field outwards. The first stator magnetic pole assembly is formed by magnetizing the first stator permanent magnet in blocks and then splicing them together. A single pole is divided into two blocks, which are radially magnetized and tangentially magnetized respectively, and the overall magnetism is concentrated inwards.

4. The magnetic transmission reduction device according to claim 3 is characterized in that: The number of pole pairs of the first rotor is p1, and the first rotor includes 8×p1 first rotor permanent magnets. The magnetization directions of two adjacent first rotor permanent magnets differ by (45-360 / (8×p1)) degrees.

5. The magnetic transmission reduction device according to claim 3 is characterized in that: The axial projection profile of the first rotor permanent magnet (422) is sector-shaped, and the dimensions of each first rotor permanent magnet are the same, with a radial thickness of H1 and an average circumferential width of W1, where H1 / W1=0.8-1.

5.

6. The magnetic transmission reduction device according to claim 3 is characterized in that: The first stator permanent magnet is configured in any of the following ways: (1) The axial projection profiles of the first stator permanent magnets are all sector-shaped and have the same size. The first stator permanent magnets are divided into radial permanent magnets (412) and tangential permanent magnets (413). The radial permanent magnets are magnetized radially, and the tangential permanent magnets are magnetized tangentially. The radial permanent magnets and the tangential permanent magnets are spliced ​​at intervals to form a first stator magnetic pole assembly. The magnetization directions of two adjacent radial permanent magnets are opposite, and the magnetization directions of two adjacent tangential permanent magnets are opposite. The radial thickness of the first stator permanent magnet is H3, the circumferential average width of the first stator permanent magnet is W3, and W3 / H3=0.52-0.6; (2) The axial projection profile of each first stator permanent magnet is a sector shape. The first stator permanent magnet is divided into a large permanent magnet (414) and a small permanent magnet (415). The large permanent magnet is magnetized radially, and the small permanent magnet is magnetized tangentially. The large permanent magnet and the small permanent magnet are spliced ​​at intervals to form a first stator magnetic pole assembly. The magnetization directions of adjacent large permanent magnets are opposite, and the magnetization directions of adjacent small permanent magnets are opposite. The angle between the two radial edges of the small permanent magnet is D2, and the radial thickness of the small permanent magnet is H5. The angle between the two radial edges of the large permanent magnet is D3, and the radial thickness of the large permanent magnet is H6. Moreover, 1.5<D3 / D2<2.2, 0.4<H6 / H5<0.

6. (3) The axial projection profile of each first stator permanent magnet is a triangle. The first stator permanent magnet is divided into an angular centripetal permanent magnet (416) and an edge centripetal permanent magnet (417). The edge centripetal permanent magnet is magnetized radially, and the angular centripetal permanent magnet is magnetized tangentially. The angular centripetal permanent magnet and the edge centripetal permanent magnet are spliced ​​at intervals to form a first stator magnetic pole assembly. The magnetization directions of two adjacent angular centripetal permanent magnets are opposite, and the magnetization directions of two adjacent edge centripetal permanent magnets are opposite. The angular centripetal permanent magnet The edges of the first stator constitute the outer edges of the first stator pole assembly, the edges of the edge-centripetal permanent magnets constitute the inner edges of the first stator pole assembly, the adjacent edges of the angular-centripetal permanent magnets and the edge-centripetal permanent magnets are equal in length and completely aligned; the outer diameter of the first stator is d5, the inner diameter of the first stator is d4, the number of pole pairs of the first stator is p3, and 0.8×d4×sin(360deg / 4p3)<d5-d4<0.9×d4×sin(360deg / 4p3).

7. The magnetic transmission reduction device according to claim 1 or 2, characterized in that: The modulation ring (430) comprises modulation teeth (435), and the modulation teeth (435) are made of a material with high saturation magnetic induction intensity.

8. The magnetic transmission reduction device according to claim 7 is characterized in that: The modulation ring (430) comprises a cage (431), the cage comprising two end plates (432) and a plurality of connecting rods (433) connected between the two end plates, the connecting rods extending axially and distributed along the circumference, and the modulation teeth (435) are fixed in the gaps between adjacent connecting rods (433).

9. The magnetic transmission reduction device according to claim 7 is characterized in that: Each modulation tooth (435) has the same size, the total number of modulation teeth is p2, the axial projection profile of the modulation teeth is fan-shaped, the angle between the two radial edges of the modulation teeth is D1, and D1 / (360deg / p2)=0.5-0.6; the radial thickness of the modulation teeth is H2, the circumferential average width of the modulation teeth is W2, and H2 / W2=0.55-1.

3.

10. The magnetic transmission reduction device according to claim 7, characterized in that: The connecting rod (433) is cylindrical, and arc grooves are formed at the middle positions of the two circumferential sides of the modulation teeth (435). The arc grooves fit the surface of the connecting rod so that the connecting rod and the cylindrical shape support each other.

11. The magnetic transmission reduction device according to claim 7, characterized in that: The first rotor pole pair number is p1, the total number of modulation teeth is p2, the first stator pole pair number is p3, and p1=|p2-p3|.

12. The magnetic transmission reduction device according to claim 1 is characterized in that: The first stator (410) is fixed to the casing (100), and a shielding ring (105) is embedded in the inner wall of the casing to reduce magnetic leakage to the outside of the casing.

13. The magnetic transmission reduction device according to claim 12, characterized in that: The following formula relationship exists among the thickness H4 of the shielding ring, the outer diameter d1 of the first rotor, the inner diameter d5 of the shielding ring, and the number of pole pairs p1 of the first rotor: d5-d1<d1×sin(360deg / 4p1), H4≥0.185×d1×(1+sin(360deg / 4p1))-0.5×d5.

14. The magnetic transmission reduction device according to claim 12, characterized in that: The shielding ring (105) is evenly divided into N sections in the axial direction, the axial length of each shielding ring section is L1, the axial length of the first stator magnetic pole assembly is L, all shielding rings are evenly distributed in the axial direction, the shielding rings located at the ends are aligned with the first stator magnetic pole assembly, the distance between the end faces of each two shielding ring sections that are close to each other is (LN*L1) / (N-1), and L1>0.65*(L / N), N<10.

15. A mid-mounted motor for a power-assisted bicycle, characterized in that include: Casing (100); A torque assembly (200) which penetrates the casing and has two ends extending out of the casing to receive external torque; The motor part (300) comprises a second stator (310) and a second rotor (320), wherein the second stator comprises an iron core (311) attached to a housing and a winding (312) wound around the iron core, the winding generating a rotating magnetic field when energized, the second rotor (320) being used to provide a permanent magnetic field matching the electromagnetic field generated by the stator winding, the second rotor (320) being located inside the second stator (310) and coaxial with the second stator, and a third air gap (330) being maintained between the second rotor and the second stator; The magnetic transmission reduction device (400) according to any one of claims 1 to 14, wherein the first rotor (420) is rotated synchronously with the second rotor (320); A two-way clutch (500) is arranged between a torque assembly (200) and a modulation ring (430) for selectively transmitting torque to it from the torque assembly or from the modulation ring. The two-way clutch has a cylindrical output shaft (501) extending out of a housing for outputting torque. The cylindrical output shaft is sleeved on the radially outer side of one end of the torque assembly (200).

16. The mid-mounted motor for power-assisted bicycle according to claim 15, characterized in that: The mid-mounted motor of the power-assisted bicycle comprises a sensor (601) and a controller (602), wherein the controller instructs the motor part to operate according to a torque signal provided by the sensor.

17. The mid-mounted motor for power-assisted bicycle according to claim 16, characterized in that: A fixed inner shell (106) is arranged outside the torque assembly (200), and a sensor (601) is arranged on the inner shell for detecting a torque signal and receiving a pedal driving torque.

18. The mid-mounted motor for power-assisted bicycle according to claim 15, characterized in that: The bidirectional clutch (500) comprises an inner sleeve (502), an outer sleeve (503), a plurality of first clutch members (504) and a plurality of second clutch members (505); the inner sleeve (502) is arranged on the torque assembly (200) and rotates together with the torque assembly; the outer sleeve (503) is arranged on the modulation ring (430) and rotates together with the modulation ring; the cylindrical output shaft (501) is sleeved on the radial outer side of the inner sleeve (502); the outer sleeve (503) is sleeved on the radial outer side of the cylindrical output shaft (501); the plurality of first clutch members (504) are distributed between the cylindrical output shaft (501) and the inner sleeve (502); and the plurality of second clutch members (505) are distributed between the cylindrical output shaft (501) and the outer sleeve (503); the first clutch member (504) and the second clutch member (505) are arranged in opposite directions.

19. The mid-mounted motor for power-assisted bicycle according to claim 15, characterized in that: The torque assembly (200) comprises a motor shaft (201) and a torque sleeve (202) sleeved on the motor shaft and rotating together with the motor shaft.

20. The mid-mounted motor for power-assisted bicycle according to claim 15, characterized in that: The second rotor (320) comprises a second rotor core (326) and a main magnetic steel (322) and an auxiliary magnetic steel (323) arranged at intervals on the circumference of the second rotor core (326); the main magnetic steel is magnetized tangentially, and the auxiliary magnetic steel is magnetized radially; the second rotor core (326) has an interval magnetic bridge (324) located between the main magnetic steel and the auxiliary magnetic steel for isolating the main magnetic steel and the auxiliary magnetic steel.

21. The mid-mounted motor for power-assisted bicycle according to claim 20, characterized in that: The second rotor core (326) has a rotor inner magnetic bridge (325) located on the inner circumference of the main magnetic steel and the auxiliary magnetic steel.

22. The mid-mounted motor for power-assisted bicycle according to claim 20, characterized in that: The main magnetic steel (322) and the auxiliary magnetic steel (323) are embedded in the second rotor iron core (326).

23. The mid-mounted motor for power-assisted bicycle according to claim 20, characterized in that: The second rotor iron core (326) extends two boots at two vertex positions corresponding to the main magnetic steel on the third air gap side to form a semi-open main magnetic steel installation groove.

24. The mid-mounted motor for power-assisted bicycle according to any one of claims 20 to 23, characterized in that: The axial projection profile of the main magnetic steel (322) is rectangular, the axial projection profile of the auxiliary magnetic steel (323) is fan-shaped, the auxiliary magnetic steel is located radially inward, the width of the main magnetic steel is w1, the radial length of the main magnetic steel is h1, the inner edge width of the auxiliary magnetic steel is w5, the radial length of the auxiliary magnetic steel is h2, and the width w2 of the magnetic bridge between the main magnetic steel and the auxiliary magnetic steel satisfies the conditions 1.2<w1 / w5<2.2, 1.5<h1 / h2<2.4, 0.08<w2 / w1<0.

15.

25. The mid-mounted motor for power-assisted bicycle according to any one of claims 20 to 23, characterized in that: The axial projection contour of the main magnetic steel is a rectangle, the axial projection contour of the auxiliary magnetic steel is a rectangle, and the auxiliary magnetic steel is located radially inward.

26. The mid-mounted motor for assisting bicycle according to any one of claims 20 to 23, characterized in that: The axial projection profile of the magnetic steel is rectangular, the axial projection profile of the auxiliary magnetic steel is fan-shaped, and the radial length of the auxiliary magnetic steel is equal to the radial length of the main magnetic steel.

27. The mid-mounted motor for power-assisted bicycle according to any one of claims 20 to 23, characterized in that: The material grade of the main magnetic steel is higher than that of the auxiliary magnetic steel.

28. The mid-mounted motor for power-assisted bicycle according to any one of claims 20 to 23, characterized in that: Uniformly distributed stator teeth (313) of equal width are formed on the second stator core (311), winding slots (314) are formed between adjacent stator teeth, and the winding slots have stator slot openings (315) facing the third air gap (330); the number of magnetic field pole pairs generated by the winding is P1, the number of stator teeth is P2, the number of second rotor pole pairs is P3, and P1+P3=P2.

29. The mid-mounted motor for power-assisted bicycle according to claim 28, characterized in that: A stator shoe portion (316) extending towards the stator slot (315) is provided on the stator tooth (313) near the third air gap (330).

30. The mid-mounted motor for power-assisted bicycle according to any one of claims 15 to 23, characterized in that: The first rotor (420) and the second rotor (320) are jointly arranged on the same cylindrical rotor shaft (700), and the cylindrical rotor shaft (700) is sleeved on the radially outer side of the torque assembly (200).

31. The mid-mounted motor for power-assisted bicycle according to any one of claims 15 to 23, characterized in that: The motor part (300) is coaxially connected in series with the magnetic transmission reduction device (400).

32. The mid-mounted motor for power-assisted bicycle according to any one of claims 15 to 23, characterized in that: The motor part (300) and the magnetic transmission reduction device (400) partially overlap in the axial direction, and the motor part is arranged inside the reduction device.

33. The mid-mounted motor for power-assisted bicycle according to any one of claims 15 to 23, characterized in that: The motor part (300) and the magnetic transmission reduction device (400) overlap in the axial direction, and the motor as a whole is placed inside the reduction device.

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