WO2012171180A1

WO2012171180A1 - All electric wheel assembly

Info

Publication number: WO2012171180A1
Application number: PCT/CN2011/075744
Authority: WO
Inventors: 杜坤梅
Original assignee: 浙江博望科技发展有限公司
Priority date: 2011-06-14
Filing date: 2011-06-14
Publication date: 2012-12-20

Abstract

An all electric wheel assembly comprises a hub (1) and a tire (2). A closed accommodation space is provided in the hub (1), and a sun wheel (4) is provided in the space. Planetary gears (5) driven to rotate by permanent-magnet motors (6) are provided along the axial direction of the sun wheel (4). The number Z of teeth of the sun wheel (4) and the number N of the planetary gears (5) meet a formula, Z=KN, wherein both K and N are integers greater than 2. The all electric wheel assembly adopts multiple permanent-magnet motors (6), and transfers torque and rotating speed to the sun wheel (4) by driving the planetary gears (5) on the output shaft of the permanent-magnet motors (6). Finally, the sun wheel (4) drives the hub (1) to rotate. The multiple permanent-magnet motors (6) have a planet-shaped layout and drive the sun wheel (4) commonly. Meanwhile, the expansion of both of torque and power can be realized, and the axial dimension of the motors (6) need not be expanded. The space of the hub (1) is fully utilized and the basic appearance feature of the hub (1) is retained.

Description

Full electric wheel assembly

Technical field

The present invention relates to an automobile wheel assembly, and more particularly to an all-electric wheel assembly driven by a plurality of three-phase permanent magnet motors arranged in a planetary arrangement.

Background technique

At present, hub motors have been widely used in electric bicycles and electric bicycles, but their use in electric vehicles is still rare. The main reason is that each wheel of an electric vehicle usually requires a continuous torque of 20-200 Nm, a continuous power of 2-200 KW, and the rotational speed of the hub is not high, usually only 1000-1500 rpm. Therefore, if the diameter is directly driven by the motor, the diameter is inevitable. It will be very large and the materials and costs used in the motor will be very high. The solution is to use a reduction gear. This method usually adds a 5:1 reducer, which can increase the speed of the motor to 5000-7500 rpm. The size of the motor can be reduced by a factor of two. This scheme is usually called For the wheel motor solution. However, this conventional wheel-side motor solution also has the disadvantage that the axial dimension of the motor is too large, and the basic shape characteristics of the flat motor of the hub are destroyed, which is not conducive to the layout of the hub on the whole vehicle. A schematic diagram of the conventional structure using a wheel motor and a direct drive motor hub is shown in FIG.

Application No. 200410037252.8, a Chinese invention patent entitled 'A structure in which a plurality of motors constitute a hub motor', proposes a structure in which a plurality of motors constitute an electric bicycle hub motor to disperse power, thereby reducing costs and configuring different powers by changing the number of motors. The purpose of the product. This solution is only applicable to low-power electric bicycle hubs, and the multiple drives of multiple motors increase control difficulty and control costs.

Summary of the invention

The technical problem to be solved by the present invention is that the axial size of the motor of the above-mentioned wheel motor for the prior art is large, which is not conducive to the overall layout of the wheel hub. The hub using the plurality of motors is only suitable for the low-power electric bicycle and the control difficulty and cost. High defect, providing an all-electric wheel assembly.

The technical solution adopted by the present invention to solve the technical problem thereof is to construct an all-electric wheel assembly. And including a wheel hub, and a tire disposed on a periphery of the hub, wherein a central accommodating space is disposed in a center of the hub, and a through hole is formed in a center of a sidewall of the accommodating space, and the through hole is assembled through a bearing. Have a hollow axle;

a sun gear passing through the axle is fixed in the accommodating space, and N planetary gears are evenly distributed along a circumferential direction of the sun gear, and each of the planetary wheels is fixed by a permanent magnet fixed on the frame The motor drives the rotation to drive the sun gear to rotate, and the reduction ratio of the sun gear to the planetary gear is 4:1-10:1;

The stator zero position and the rotor zero position of the permanent magnet motor are both aligned with the zero position of the planetary gear such that the zero position of the planetary gear meshes with the tooth groove of the sun gear; the number of teeth of the sun gear is Z, then Z satisfies the following formula:

Z = KN , where N and K are both integers greater than two.

The all-electric wheel assembly of the present invention, wherein the accommodating space is surrounded by a substrate matching the shape of the hub and for fixing the permanent magnet motor and a side wall of the hub, On the substrate, a through hole equal in number to the number of planet wheels is evenly distributed in a circumferential direction of the hub, and an output shaft of the permanent magnet motor is fitted into the through hole through a bearing.

The all-electric wheel assembly of the present invention, wherein the substrate is further provided with a dynamic sealing structure at a periphery of the hub.

The all-electric wheel assembly of the present invention, wherein one of the permanent magnet motors is further provided with a position sensor.

The all-electric wheel assembly of the present invention, wherein the position sensor comprises a Hall switch, a magnetic encoder, a resolver or a photoelectric encoder.

The all-electric wheel assembly of the present invention, wherein the windings of all of the permanent magnet motors and the lead wires of the position sensor form a wire harness sealed within the axle and threaded out of the axle.

The all-electric wheel assembly of the present invention, wherein the permanent magnet motors are all three-phase permanent magnet motors of a Y-type winding, and all of the permanent magnet motors are electrically connected in parallel or in series.

The all-electric wheel assembly of the present invention, wherein the all-electric wheel assembly further comprises a drive controller, the drive controller driving the permanent magnet motor with a three-phase square wave current or a three-phase sinusoidal current.

The all-electric wheel assembly of the present invention, wherein the sun gear comprises a metal gear, the planetary gear comprising a metal gear or a non-metallic gear.

The all-electric wheel assembly of the present invention, wherein the sun gear comprises an internal gear or an external gear.

The all-electric wheel assembly of the present invention, wherein The all-electric wheel assembly also includes a brake mounted coaxially with the sun gear, the brake including a disc brake or a drum brake.

The all-electric wheel assembly embodying the invention has the following beneficial effects: the invention adopts multiple permanent magnet motors to transmit torque and rotational speed to the sun gear by driving the planetary gears on the output shaft of the permanent magnet motor and finally drives the hub to rotate by the sun gear. . A plurality of permanent magnet motors are arranged in a planetary shape to jointly drive the sun gear, and at the same time achieve the purpose of torque and power expansion, and the axial dimension of the motor does not have to be enlarged, and the space of the hub is fully utilized to maintain the basic shape characteristics of the hub.

DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic view showing the structure of a wheel hub motor and a direct drive motor hub;

2 is a schematic structural view of a preferred embodiment of an all-electric wheel assembly according to the present invention;

Figure 3 is a view showing the meshing of the sun gear and the planetary wheel in a preferred embodiment of the all-electric wheel assembly of the present invention;

4 is a circuit diagram showing a parallel connection of three three-phase windings of three permanent magnet motors in a preferred embodiment of an all-electric wheel assembly according to the present invention;

Figure 5 is a circuit diagram showing the series connection of three three-phase windings of three permanent magnet motors in a preferred embodiment of the all-electric wheel assembly of the present invention.

detailed description

The invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 2, in a preferred embodiment of the present invention, the all-electric wheel assembly includes a hub 1 and a tire 2 disposed at a periphery of the hub 1. The central portion of the hub 1 is provided with a sealed receiving space. A through hole is formed in the center of the side wall of the accommodating space, and a hollow axle 3 is assembled through the bearing in the through hole. Secondly, a sun gear 4 passing through the axle 3 is fixed in the accommodating space, and in the above-mentioned accommodating space, N planet wheels 5 are evenly distributed along the circumferential direction of the sun gear 4, and each of the planet wheels 5 Both are driven by the permanent magnet motor 6 fixed on the frame, which in turn drives the sun gear 4 to rotate, and in order to control the rotational speed of the wheel, the axial dimension of the motor is minimized, and the reduction ratio of the sun gear 4 to the planetary gear 5 is specified. It is 4:1-10:1.

In the preferred embodiment of the present invention, the rotational speed of the hub 1 is about 1000 rpm, and the reduction ratio is set to be about 4:1 to 10:1, that is, the rotational speed of the motor is set to about 4,000 to 10,000 rpm. Generally speaking, the motor speed can be increased by 4 to 10 times, and the motor power can be increased by 4 to 10 times because: the motor power P=Tω, T is the torque, ω=2 n n/60 It is the angular velocity, the T torque is constant, the motor size is constant, the ω is increased, and the motor output power P is also increased. The invention improves the rotational speed of the motor by the deceleration of the gear, and the power density of the electric wheel hub is improved. And the motor speed can not exceed 6000 ~ 10000 rpm, because the iron loss and noise of the motor will increase sharply, the life of the motor is also a problem. Therefore, it is reasonable to set the reduction ratio to be around 4:1 to 10:1.

It should be noted that, as shown in FIG. 3, at the time of assembly, the stator zero position 601 and the rotor zero position of the permanent magnet motor 6 should be aligned with the zero position 501 of the planetary gear 5, so that the zero position 501 of the planetary gear 5 is made. Engaging with the tooth groove of the sun gear 4, so that the phase of the counter electromotive force of the three-phase windings of the plurality of permanent magnet motors 6 is the same when the sun gear 4 is rotating, and if the number of teeth of the sun gear 4 is Z, the sun The following formula should be satisfied between the number of teeth Z of the wheel and the number of planet wheels 5:

Z = KN , where N and K are both integers greater than two.

This is because, if N=3, the back electromotive forces of the three permanent magnet motors are E _a1 , E _a2 , E _a3 , and the phases are the same, after series connection:

The total electromotive force E _a =E _a1 +E _a2 +E _a3 =3E _a1 . If the phases are different, the magnitude of the back electromotive force synthesized by E _a after series will decrease, the phase will also change, and the synthesized motor efficiency will inevitably decrease. Therefore, it is important to ensure zero alignment. At the same time, with three permanent magnet motors 6, the number of teeth Z of the corresponding sun gear 4 should be a multiple of 3, which is also very important, because if the number of teeth Z of the sun gear 4 is a multiple of 4 The three planetary gears 5 are engaged with the slots of the sun gear 4, which are asymmetrical anyway, so it is impossible to ensure that the phases of the three-phase windings of the three permanent magnet motors 6 are the same.

Further, the above-mentioned accommodating space is surrounded by the substrate 12 for matching the shape of the hub 1 and for fixing the permanent magnet motor 6 and the side wall of the hub 1. On the substrate 12, there are uniformly distributed through holes in the circumferential direction of the hub 1 in the same number as the planetary gears 5, and the output shaft of the permanent magnet motor 6 is fitted into the through holes through the bearings 7. The sun gear 4 is rigidly connected to the hub 1, so that the hub 1 can be rotated relative to the substrate 12 of the fixed permanent magnet motor 6.

Preferably, a dynamic sealing structure 11 is further provided at a periphery (i.e., the spoke 10) where the substrate 12 is in contact with the hub 1. The dynamic sealing structure 11 may be a stator metal ring or a stator metal ring with a labyrinth, and one or several rubber rings on the rotor, or a sealing ring of a composite material to form a dynamic sealing structure 11; or a metal ring or a labyrinth on the rotor The stator metal ring, one or several rubber rings on the stator, or a sealing ring of the composite material constitutes the dynamic sealing structure 11. When the hub 1 rotates, the sun gear 4 rotates and generates a positive pressure in the sealed accommodating space, thereby ensuring a positive pressure motion seal in the sealed accommodating space.

Preferably, one of the permanent magnet motors 6 is further provided with a position sensor, and the set sensor may be a Hall switch, a magnetic encoder, a resolver or a photoelectric encoder.

In a preferred embodiment of the invention, the windings of all permanent magnet motors 6 and the leads of the position sensor are made into a wire harness sealed within the hollow axle 3 and threaded out of the axle 3.

Further, the above permanent magnet motor 6 adopts a three-phase permanent magnet motor of a Y-type winding, and all of the permanent magnet motors 6 are electrically connected in parallel or in series. As shown in FIG. 4, a plurality of Y-type winding three-phase permanent magnet motors may be connected in parallel according to U phase, V phase, and W phase to form a set of UVW three-phase windings, or may be U as shown in FIG. Phase, V phase, and W phase are connected in series to form a set of UVW three-phase windings.

Since a plurality of three-phase permanent magnet motors 6 are engaged with the sun gear 4 through the respective planet wheels 5, an equivalent three-phase permanent magnet motor that is mechanically coaxial with the respective output shafts is connected in series. When the sun gear 4 rotates, the phases of the counter electromotive forces of the plurality of three-phase permanent magnet motors 6 are the same; conversely, when the plurality of three-phase permanent magnet motors 6 are driven, since the respective planetary gears 5 are engaged with one of the sun gears 4, Therefore, the rotational speeds of the plurality of three-phase permanent magnet motors 6 are inevitably coincident with the steering, so that the plurality of three-phase permanent magnet motors 6 are equivalent to an equivalent three-phase permanent magnet motor in which the output shafts are connected in series and mechanically coaxial.

Therefore, it is possible to use one drive controller to drive an equivalent three-phase permanent magnet motor, that is, a plurality of permanent magnet motors 6 using a three-phase square wave current or a three-phase sinusoidal current.

Further, the sun gear 4 may be a metal gear, and the planetary gear 5 may be any one of a metal gear or a non-metal gear. And the sun gear 4 may be any of an internal gear or an external gear. In a preferred embodiment of the invention, the sun gear 4 is an external gear.

It will be understood that the all-electric wheel assembly should also include a brake mounted coaxially with the sun gear 4, the brake typically comprising a brake member 9 and a brake disc 8, which are well known in the art and can be used with disc brakes or drums. Any of the brakes.

The invention adopts a plurality of permanent magnet motors to transmit torque and rotational speed to the sun gear by driving the planetary gears on the output shaft of the permanent magnet motor and finally drive the hub to rotate by the sun gear. A plurality of permanent magnet motors are arranged in a planetary shape to jointly drive the sun gear, and at the same time achieve the purpose of torque and power expansion, and the axial dimension of the motor does not have to be enlarged, and the space of the hub is fully utilized to maintain the basic shape characteristics of the hub. In addition, the multi-motor and multi-planetary gear drive method has the advantages that the output shaft is multi-pointed, symmetrically and uniformly driven and driven along the circumference, and the force and mass distribution are symmetric and uniform, and the influence of the motor gear gap is also driven by the multi-point drive. The average effect is greatly suppressed, so the noise when the hub is rotated at a high speed is also greatly reduced.

Therefore, the invention has a series of advantages such as high power density, large torque, small torque fluctuation, low noise, strong overload capability, uniform mass distribution, high material utilization rate, low cost and small axial dimension.

The above embodiments are merely illustrative of the technical concept and the features of the present invention. The purpose of the present invention is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention without limiting the scope of the present invention. Equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the appended claims.

Claims

An all-electric wheel assembly comprising a hub (1) and a tire (2) disposed on a periphery of the hub (1), characterized in that a central portion of the hub (1) is provided with a sealed housing a space, a center of the side wall of the accommodating space is provided with a perforation, wherein the perforation is fitted with a hollow axle (3) through a bearing;

A sun gear (4) passing through the axle (3) is fixed in the accommodating space, and N planetary wheels (5) are uniformly arranged in a circumferential direction of the sun gear (4), each of which The planetary gear (5) is driven to rotate by a permanent magnet motor (6) fixed to the frame to drive the sun gear (4) to rotate, and the sun gear (4) and the planetary gear (5) are decelerated. The ratio is 4:1-10:1;

The stator zero position (601) and the rotor zero position of the permanent magnet motor (6) are both aligned with the zero position (501) of the planetary gear (5) such that the zero position of the planetary gear (5) (501) ) engaging with the tooth groove of the sun gear; the number of teeth of the sun gear (4) is Z, then Z satisfies the following formula:

Z = KN, where N and K are both integers greater than two.

2. The all-electric wheel assembly according to claim 1, wherein the accommodating space is matched by the shape of the hub (1) and used to fix the permanent magnet motor (6) a substrate (12) enclosing a side wall of the hub (1), on the substrate (12), equally distributed in the circumferential direction of the hub (1) with the number of the planet wheels (5) The through hole, the output shaft of the permanent magnet motor (6) is fitted into the through hole through a bearing (7).

3. The all-electric wheel assembly according to claim 2, characterized in that the substrate (12) is further provided with a dynamic sealing structure (11) at a periphery of the hub (1).

4. The all-electric wheel assembly of claim 1 wherein a position sensor is further mounted on one of said permanent magnet motors (6).

5. An all-electric wheel assembly according to claim 4 wherein the position sensor comprises a Hall switch, a magnetic encoder, a resolver or a photoelectric encoder.

6. An all-electric wheel assembly according to claim 5, wherein all of said permanent magnet motor (6) windings and position sensor lead wires are sealed within said axle (3) and from said The axle (3) is worn out.

The all-electric wheel assembly according to any one of claims 1 to 6, wherein the permanent magnet motor (6) is a Y-phase winding three-phase permanent magnet motor, and all of the permanent magnets The motor (6) is electrically connected in parallel or in series.

8. The all-electric wheel assembly of claim 7, wherein the all-electric wheel assembly further comprises a drive controller, the drive controller employing a three-phase square wave current to the permanent magnet motor (6) Or three-phase sine wave current drive.

9. An all-electric wheel assembly according to claim 1 wherein the sun gear (4) comprises an internal gear or an external gear.

10. The all-electric wheel assembly of claim 1 wherein the all-electric wheel assembly further comprises a brake mounted coaxially with the sun gear (4), the brake comprising a disc brake or drum Brake.