WHEEL STRUCTURE WITH BUILT-IN REDUCER AND MOTOR

Abstract

A wheel structure with a built-in reducer and motor is provided. As the driving wheel in a rudder wheel, which has a high degree of integration and significantly reduces the overall height of the rudder wheel while maintaining high speed and acceleration. The wheel structure includes a wheel coupled to a reducer, a drive motor connected to the reducer, and the reducer.

Claims

1. A wheel structure with a built-in reducer and motor, comprising: a wheel coupled to a reducer; a drive motor connected to the reducer; and the reducer, wherein the reducer is connected at each end to the drive motor and the wheel, and the reducer decelerates and increases a torque of an output of the drive motor and feeds the output of the drive motor to the wheel; wherein the reducer and the drive motor are built into the wheel; external support points of the wheel structure with the built-in reducer and motor are located at an outermost of two ends of the wheel structure as a whole, in a form of a simply supported beam structure.

2. The wheel structure according to claim 1, wherein the wheel comprises a hub and a tyre, the hub has a hollow structure with an offset “I” shape in a cross-section and vertical spokes offset in a middle to provide a strength support; the vertical spokes divide a space inside the wheel into two different volumes of a hub cavity to house the drive motor and the reducer, respectively.

3. The wheel structure according to claim 2, wherein the inner cavity gradually increases in a diameter from inside to outside, providing a space for the motor and the reducer to be mounted while increasing an assembly clearance; and an outer cylindrical surface of the hub has grooves for bonding the tyres.

4. The wheel structure according to claim 1, wherein the drive motor is a high power motor in a small diameter, the drive motor is sized, and the drive motor is allowed to be arranged inside the wheel.

5. The wheel structure according to claim 1, wherein the reducer is a planetary reducer comprising a gear ring holder, a ring bearing, an inner gear ring, a gear ring holder, a wheel planetary holder, an outer planetary holder, a sun gear, a retaining ring, a sun gear shaft, a motor output shaft, a pressure plate, a key, a planetary holder flange bearing, a gear ring holder flange bearing, a planetary gear shaft, a planetary gear flange bearing, a planetary gear, and wheel flange bearings; the motor output shaft of the drive motor is connected to the sun gear shaft by pressing a D-shaped shaft located at an end of the motor output shaft by means of the pressure plate, the sun gear shaft is connected to the sun gear co-axially by means of the key, a sun gear end face is provided with the axially restrained retaining ring; the outer planetary holder and the wheel planetary holder are connected to the hub by means of countersunk screws, the planetary gear is restrained to the planetary gear shaft by means of two planetary gear flange bearings, the planetary gear shaft is connected to an outer planetary gear and a wheel planetary gear, and the planetary gear is restrained between the outer planetary gear and the wheel planetary gear; the inner gear ring and a wheel gear ring holder are attached to a ring mounting bracket by means of hexagon socket screws.

6. The wheel structure according to claim 5, wherein the wheel is coaxially constrained to the motor output shaft by means of a wheel flange bearing, the wheel gear ring holder is coaxially constrained to the wheel planetary holder by means of a gear ring bearing, the outer planetary holder is coaxially constrained to the sun gear shaft by means of the planetary holder flange bearing, and the sun gear shaft is coaxially constrained to the gear ring holder by means of a gear ring holder flange bearing.

7. The wheel structure according to claim 5, wherein the planetary reducer has the inner gear ring as a fixed end, the sun gear as an input end and the wheel planetary holder as an output end, the sun gear engages with the planetary gear, the planetary gear engages with the inner gear ring, and the sun gear drives the planetary gear to rotate forward on the fixed inner gear ring when the sun gear rotates, driving the wheel planetary holder to decelerate the output coaxially with the sun gear; the input end of the planetary reducer is connected to the drive motor, the output end is connected to the wheel, and the fixed end serves as a support for the reducer.

8. The wheel structure according to claim 2, wherein a wheel size needs to be designed in conjunction with a tyre size, a wheel width is designed taking into account a tyre width, a drive motor width and a reducer width; a width of a single tyre is set to a; the hub needs to be arranged with K tyres, wherein a hub width is A=ka (k is a positive integer); the hub width A needs to be designed, wherein a motor rotor and the reducer are arranged inside the hub; outer dimensions of the hub are configured to match an inner diameter of the tyres, wherein the inner diameter is set as D; a maximum diameter of the inner cavity of the hub is d1, a minimum diameter of the inner cavity of the hub is d2 and a maximum diameter of the motor rotor is d, wherein D>d.sub.1>d.sub.2>d; considering that the space occupied by the motor in the inner cavity of the hub is larger and wider, a cantilever on a motor side of the hub is longer and has a largest deformation than a cantilever on a reducer side, with the largest deformation occurring at an outermost end of the cantilever on the motor side of the hub; let an initial clearance at the outermost end of the cantilever on the motor side of the hub be u=d.sub.1−d; when the hub is deformed by a force, a clearance is always configured to be greater than zero, wherein a maximum hub deformation variable u.sub.1<u.

9. The wheel structure according to claim 8, wherein a wheel design method analyses forces on the hub by means of a finite element analysis and selects a suitable hub material, wherein the suitable hub material meets strength and clearance requirements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows a diagram of the overall structure of a wheel with a built-in reducer and motor

[0023] FIG. 2 shows a cross-sectional view of the hub of the wheel structure with built-in reducer and motor

[0024] FIG. 3 shows an axonometric view of the hub of the wheel structure with built-in reducer and motor.

[0025] FIG. 4 shows a sectional view of the reducer of the wheel structure with built-in reducer and motor

[0026] FIG. 5 shows a finite element analysis stress diagram of the hub of the wheel structure with built-in reducer and motor.

[0027] FIG. 6 shows the FEA displacement diagram of the wheel structure with built-in reducer and motor.

[0028] In the drawing. 1 is the wheel, 1-1 is the hub, 1-1-1 is the outer hub, 1-1-2 is the spokes, 1-1-3 is the inner hub cavity, 1-1-4 is the recess, 1-2 is the tyre; 2 is the drive motor; 3 is the reducer, 3-1 is the wheel gear ring holder, 3-2 is the ring bearing, 3-3 is the inner gear ring, 3-4 is the socket head screw, 3-5 is the gear ring holder, 3-6 is the wheel planetary holder, 3-7 for outer planetary holder, 3-8 for countersunk screw, 3-9 for sun gear, 3-10 for retaining ring, 3-11 for the sun gear shaft, 3-12 for the motor output shaft, 3-13 for the pressure plate, 3-14 for the key, 3-15 for the planetary holder flange bearing, 3-16 for the ring holder flange bearing, 3-17 for the planetary gear shaft, 3-18 for the planetary gear flange bearing, 3-19 for the planetary gear, and 3-20 for the wheel flange bearing.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention is described in further detail below in conjunction with the accompanying drawings and specific examples:

[0030] The present invention a wheel structure with a built-in reducer and motor, including a wheel 1, a drive motor 2 and a reducer 3, as shown in FIG. 1.

[0031] The wheel 1 includes a hub 1-1 and a tyre 1-2. The hub 1-1 is a hollow structure with an “I” shape cross-section and vertical spokes 1-1-2 offset in the middle to provide strength support; the spokes 1-1-2 divide the space inside the wheel 1 into two different volume spaces 1-1-3 on the left and right side of the hub, where the drive motor 2 and the reducer 3 are placed respectively. The inner diameter of the wheel cavity 1-1-3 gradually increases from the inside to the outside, providing space for the motor 2 and reducer 3 to be installed while increasing the assembly clearance; the upper and lower horizontal part of the “I” is the wheel outer rim 1-1-1, which is cylindrical in shape and has grooves 1-1-4 on its surface for bonding with the tyre 1-2, as shown in FIGS. 2 and 3. Tyre 1-2 is a hot-melt bald-head tyre, an existing product with a width of 26 mm, an outer diameter of 66 mm and an inner diameter of 54 mm, with a high coefficient of friction.

[0032] The drive motor 2 is a small diameter, high power motor, providing a sufficient power source for wheel 1, arranged on the side of the larger spokes 1-1-2 in the inner cavity 1-1-3 of the wheel.

[0033] The reducer 3 of the wheel is a planetary reducer including a wheel gear ring holder 3-1, a gear ring bearing 3-2, an inner gear ring 3-3, a gear ring holder 3-5, a wheel planetary holder 3-6, an outer planetary holder 3-7, a sun gear 3-9, a retaining ring 3-10, a sun gear shaft 3-11, a motor output shaft 3-12, a pressure plate 3-13, a key 3-14, a planetary holder flange bearing 3-15, a gear ring holder flange bearing 3-16, planetary gear shaft 3-17, planetary gear flange bearing 3-18, planetary gear 3-19 and wheel flange bearing 3-20, etc. The motor output shaft 3-12 of the drive motor 2 is connected to the sun gear shaft 3-11 by pressing the D-shaped shaft located at its end through the pressure plate 3-13, and the sun gear shaft 3-11 is connected to the sun gear 3-9 co-axially through the key 3-14, and the sun gear 3-9 is provided with an axially restrained retaining ring 3-10 on its end face; the outer planetary holder 3-7 and the wheel planetary holder 3-6 are connected to the hub 1—through the countersunk head screw 3-8, and the planetary gear 3-7 and the wheel flange bearing 3-6 are connected to the hub 1 The planetary gear 3-19 is restrained on the planetary gear shaft 3-17 by two planetary gear flange bearings 3-18, and the planetary gear shaft 3-17 is connected to the outer planetary holder 3-7 and the wheel planetary holder 3-6, and the planetary gear 3-19 is restrained to move between the outer planetary holder 3-7 and the wheel planetary holder 3-6; the inner gear ring 3-3 and the wheel gear ring holder 3-1 are connected by hexagonal screws 3-4 to the gear ring holder 3-5.

[0034] Hub 1-1 is coaxially bound to motor output shaft 3-12 via wheel flange bearing 3-20, wheel ring holder 3-1 is coaxially bound to wheel planetary holder 3-6 via ring bearing 3-2, outer planetary holder 3-7 is coaxially bound to sun gear shaft 3-11 via planetary holder flange bearing 3-15, sun gear shaft 3-11 is coaxially bound to gear ring through ring holder flange bearing 3-16, as shown in FIG. 4.

[0035] The planetary reducer has the inner gear ring 3-3 as the fixed end, the sun gear 3-9 as the input end and the wheel planetary holder 3-6 as the output end, the sun gear 3-9 engages with the planetary gear 3-19, the planetary gear 3-19 engages with the inner gear ring 3-3, the sun gear 3-9 rotates to drive the planetary gear 3-19 to rotate forward on the fixed inner gear ring 3-3, driving the wheel planetary holder 3-6 coaxially to the sun gear 3-9 deceleration output. The input end of the planetary reducer is connected to the drive motor 2, the output end is connected to the wheel 1 and the fixed end serves as a support for the reducer 3.

[0036] The outer rim of the wheel 1-1-1 is designed to match the size of tyre 1-2. The width of hub 1-1 is designed taking into account the width of tyre 1-2, the width of drive motor 2 and the width of reducer 3. The width of a single tyre 1-2 is 26 mm, and the lateral arrangement of two tyres 1-2 brings the total width of the wheel to 52 mm, which is the width for the drive motor 2 and reducer 3 to be set in the wheel cavity 1-1-3 and just fill the wheel cavity 1-1-3 in a compact layout. In this example, the drive motor 2 has a diameter of 50 mm and the hub cavity 1-1-3 has a diameter of 51 to 52.5 mm widened from the inside to the outside, with a maximum clearance of 1 0.25 mm between the drive motor 2 and the hub cavity 1-1-3. analysis of the forces on hub 1-1, as shown in FIGS. 5 and 6. The design weight of a robot is 50 kg and the number of wheels is 4. Therefore, the force on a single wheel is 15 kgf. Aluminium alloy is chosen as the material of hub 1-1. Under this force condition, the maximum stress of hub 1-1 is less than the yield strength of the material, and the maximum deformation is less than the gap between the drive motor 2 and the inner cavity of hub 1-1-3, meeting the strength and deformation requirements of the material.

[0037] The wheel integral with built-in reducer and drive motor is connected to the outside through the threads at the end of the drive motor 2 and the threads of the gear ring holder 3-5 as two support points for the wheel structure integral with built-in reducer and motor. The two support points are on the outermost side of the wheel structure integral with built-in reducer and motor, making it a simple beam structure support with high load carrying capacity.