Speed reduction hub electric wheel integrated with electronic parking mechanism

Abstract

The invention relates to a speed reduction hub electric wheel integrated with an electronic parking mechanism, which comprises an electric wheel shell and a shell end cover connected with the electric wheel shell, the electric wheel shell is rigidly connected with an axle, the shell end cover is connected with a rim, and a motor and a planetary gear reducer are nested on the inner side of the electric wheel shell. A drum brake and a hub bearing unit are arranged on the inner side of the shell end cover in an embedded mode, and the electronic parking mechanism is arranged on an axle or an electric wheel shell in a sleeving mode and connected to the drum brake through a parking inhaul cable. Compared with the prior art, the electric wheel assembly has the advantages that the planetary gear reducer is nested in the motor, the brake is nested on the outer side of the hub bearing unit and is positioned between the rim and the shell end cover, and the scheme of the drum brake and the electronic parking actuator pull cable is adopted, so that the integration level of the electric wheel assembly is improved, the axial size is reduced, and the electric wheel assembly is more compact in structure. And meanwhile, the electronic parking mechanism is integrated with the axle or the electric wheel shell, so that the loss in the tensioning force transmission process can be reduced, and the transmission efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hub motor electric drive, and particularly relates to a reduction hub motor electric wheel integrated with an electronic parking mechanism. BACKGROUND

[0002] Hub motor electric drive is a driving method in which an electric motor is embedded in a wheel. Compared with the traditional engine and transmission driving method, this technology brings many advantages, including a simplified power transmission path, efficient energy utilization, improved suspension design and vehicle balance, lower noise and vibration levels, and excellent vehicle handling and reliability.

[0003] Currently, the development of hub motor electric drive technology mainly focuses on two directions: hub direct drive electric wheel and hub reduction electric wheel. Compared with the hub direct drive electric wheel method in which the electric motor is directly embedded in the wheel, the hub reduction electric wheel further integrates the electric motor and the reducer in the wheel. This method is beneficial to reduce manufacturing complexity and improve system efficiency, and is widely used in the fields of electric bicycles and electric motorcycles, and is also gradually applied in the electric vehicle market.

[0004] When applying the hub reduction electric wheel scheme to electric vehicles, it is often necessary to cooperate to realize the parking brake of the electric vehicle. The traditional method, such as Chinese patent CN116605042A, designs a disc brake connected directly with the motor rotor, and uses the electronic rotor to drive the disc brake to move to realize the braking process. However, this method has high disc brake wear due to the high speed of the rotor, and has the defect of large axial size in structure. In addition, most existing vehicles use an electronic parking (EPB) mechanism. However, the electronic parking mechanism usually occupies a large volume, which on the one hand makes it difficult to integrate into the electric wheel structure, and on the other hand has the problem of low transmission efficiency. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art and provide a reduction hub motor electric wheel integrated with an electronic parking mechanism, which can improve the integration of the electric wheel assembly, reduce the axial size, and at the same time ensure the transmission efficiency and reliability of the electronic parking.

[0006] The purpose of the application can be realized by the following technical solutions: a reduction hub motor wheel integrated with an electronic parking mechanism, comprising an electric motor wheel shell and a shell end cover connected thereto, the electric motor wheel shell is rigidly connected with an axle, the shell end cover is connected with a rim, a motor and a planetary gear reducer are nested on the inner side of the electric motor wheel shell, a drum brake and a hub bearing unit are nested on the inner side of the shell end cover, the electronic parking mechanism is sleeved on the axle or the electric motor wheel shell and is connected to the drum brake through a parking cable.

[0007] Further, the motor comprises a stator and a rotor, the stator is nested on the inner side of the electric motor wheel shell, and the rotor is nested on a rotor support, and the planetary gear reducer is nested and installed in the interior of the rotor support.

[0008] Further, the planetary gear reducer comprises a sun gear, a planet gear, a planet gear ring, a planet carrier and a planet carrier output shaft, the planet gear, the planet carrier, the sun gear and the planet gear ring are connected in floating connection in the axial direction, and the sun gear is connected in radial torsion resistance with the rotor support through a first spline.

[0009] Further, a hub flange plate is sleeved on the planet carrier output shaft, the hub bearing unit is assembled on the radial outer side of the planet carrier output shaft, and the rim is installed on the axial outer side of the planet carrier output shaft.

[0010] Further, the hub bearing unit comprises a hub bearing seat and a pair of back-to-back installed hub ball bearings, the inner side of the hub bearing unit is connected with the planet carrier output shaft in interference, and the outer side of the hub bearing unit is fixed on the shell end cover in interference.

[0011] Further, the drum brake comprises a brake bottom plate and a brake drum, the brake bottom plate is installed on the hub bearing seat and is hard connected with the surface of the shell end cover, and brake shoes, a brake cylinder, a parking rocker arm and a cable interface are integrally installed on the brake bottom plate.

[0012] The brake drum is installed on the hub flange plate, and the hub flange plate is connected with the rim through a pre-buried connecting bolt.

[0013] Further, a magnetic ring is sleeved on the inner side of the hub flange plate, and a wheel speed sensor is installed on the brake bottom plate.

[0014] Further, when the electronic parking mechanism is sleeved on the axle, the parking cable is specifically a long brake cable, the long brake cable is inserted along the edge of the shell end cover and connected to the cable interface of the brake bottom plate.

[0015] Further, when the electronic parking mechanism is sleeved on the electric wheel shell, the parking cable is specifically a short brake cable, the short brake cable is inserted along the edge of the electric wheel shell and connected to the cable interface of the brake bottom plate.

[0016] Further, a sleeve is arranged on the parking cable, and the sleeve is filled with lubricating grease.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] The present application nests a motor and a planetary gear reducer inside the electric wheel shell, nests a drum brake and a hub bearing unit inside the shell end cover, and sleeves an electronic parking mechanism on the axle or the electric wheel shell, and connects the electronic parking mechanism to the drum brake through a parking cable. In this way, the planetary gear reducer is nested inside the motor, the brake is nested outside the hub bearing unit and between the rim and the shell end cover, and the drum brake and the electronic parking mechanism with the cable are used, which not only improves the integration of the electric wheel assembly and reduces the axial size, but also integrates the electronic parking mechanism with the axle or the electric wheel shell, so that the loss in the tension transmission process is reduced and the transmission efficiency is improved.

[0019] The present application installs the brake bottom plate on the hub bearing seat and hard connects the brake bottom plate with the surface of the shell end cover, and integrally installs brake shoes, a brake cylinder, a parking rocker arm and a cable interface on the brake bottom plate; the brake drum is installed on the hub flange plate, so that the brake drum is connected to the rim in a torsion-resistant manner and rotates with the rim, overcoming the defects of high wear and high speed of disc brakes in similar products, and the entire brake is located between the in-wheel motor and the rim, fully utilizing the internal space of the rim and saving the axial space. In addition, a magnetic ring is sleeved on the inner side of the hub flange plate, and a wheel speed sensor is installed on the brake bottom plate, and the magnetic ring and the wheel speed sensor are coaxially arranged with the drum brake and the wheel shaft, effectively saving the radial space.

[0020] The present application designs to sleeve the electronic parking mechanism on the electric wheel shell or the axle, when the electronic parking mechanism is sleeved on the axle, a long brake cable is selected, the long brake cable is inserted along the edge of the shell end cover and connected to the cable interface of the brake bottom plate; when the electronic parking mechanism is sleeved on the electric wheel shell, a short brake cable is selected, the short brake cable is inserted along the edge of the electric wheel shell and connected to the cable interface of the brake bottom plate. The wire routing of the parking cable is guided through the hole in the edge of the shell, which not only realizes the integration of the electronic parking mechanism and the electric wheel assembly, but also efficiently and reliably transmits the parking force to the brake bottom plate.

[0021] The present application designs to sleeve the electronic parking mechanism on the electric wheel shell or the axle, when the electronic parking mechanism is sleeved on the axle, a long brake cable is selected, the long brake cable is inserted along the edge of the shell end cover and connected to the cable interface of the brake bottom plate; when the electronic parking mechanism is sleeved on the electric wheel shell, a short brake cable is selected, the short brake cable is inserted along the edge of the electric wheel shell and connected to the cable interface of the brake bottom plate. The wire routing of the parking cable is guided through the hole in the edge of the shell, which not only realizes the integration of the electronic parking mechanism and the electric wheel assembly, but also efficiently and reliably transmits the parking force to the brake bottom plate. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Schematic diagram of internal configuration of the present application;

[0023] Figure 2 Schematic diagram of the brake bottom plate in the present application;

[0024] Figure 3 Schematic diagram of the axle integrated electronic parking mechanism in Example 1;

[0025] Figure 4 Schematic diagram of the electric wheel housing integrated electronic parking mechanism in Example 2;

[0026] Marked description in the figure: 1, electric wheel housing, 2, housing end cover, 3, housing connecting threaded hole, 4, cooling inlet and outlet port, 5, cooling oil way, 6, left deep groove ball bearing, 7, brake oil way interface, 8, brake bottom plate, 9, hub bearing unit, 10, planetary gear ring, 11, sun gear, 12, planetary gear (including wheel shaft and needle bearing), 13, planetary carrier, 14, planetary carrier output shaft, 15, hub ball bearing, 16, hub bearing seat, 17, brake drum, 18, rim, 19, hub flange plate, 20, pre-buried connecting bolt, 21, stator, 22, rotor support, 23, rotor, 24, first spline, 25, planetary carrier output shaft spline, 26, sun gear small end shaft, 27, right small end deep groove ball bearing;

[0027] 31, wheel speed sensor and magnetic ring, 32, EPB actuator, 33, rear axle, 34, long brake cable, 35, parking rocker arm;

[0028] 41, EPB actuator output end, 42, short brake cable (including steel cable and rubber), 43, sleeve (internal lubricating grease injection), 44, sleeve fixing plate, 45, brake cable guide fixing plate;

[0029] 51, oil inlet hole, 52, brake wheel cylinder, 53, gap adjusting spring 54, parking cable, 55, exhaust hole, 56, upper return spring, 57, brake shoe, 58, lower return spring. DETAILED DESCRIPTION

[0030] The present application will be described in detail below in combination with the drawings and specific examples.

[0031] The scheme considers that the radial assembly design space of the hub reduction electric wheel configuration is limited within the rim, which determines the boundary conditions of the arrangement space of the electronic parking mechanism EPB. However, the axial design space allows to exceed the size of the rim and the tire, but this part of the size should be compressed as much as possible, otherwise there will be a large conflict with the connection of the axle. In addition, the electric wheel outer shell should be rigidly connected to the axle, and the cooling elements and cooling oil rails, connecting bolts (holes), connecting flanges and other mechanisms are integrated on the surface to meet the pipeline arrangement and integration with other key components. The electric wheel outer shell is a fixed part, which needs to bear the fixing function of other fixed parts, including but not limited to the motor stator, planetary gear ring and brake bottom plate; at the same time, the part and its related matching parts need to bear the positioning, bearing and sealing function of the fixed end of the bearing of other rotating parts, including but not limited to the sun gear shaft bearing and the hub bearing.

[0032] Therefore, the scheme provides a reduction hub electric wheel integrated with an electronic parking mechanism, which comprises an electric wheel shell 1 and a shell end cover 2 connected thereto, wherein the electric wheel shell 1 is rigidly connected to the axle, the shell end cover 2 is connected to the rim 18, the electric wheel shell 1 is nested with a motor and a planetary gear reducer inside, the shell end cover 2 is nested with a drum brake and a hub bearing unit 9 inside, the electronic parking mechanism is sleeved on the axle or the electric wheel shell 1, and is connected to the drum brake through a parking cable, the parking cable is arranged in the circumferential direction along the inside of the electric wheel outer shell and the rim, is installed on the shell stopper mounting surface, and is designed to pass through the parking cable through the axial hole of the shell.

[0033] Specifically, the motor comprises a stator 21 and a rotor 23, the stator 21 is nested inside the electric wheel shell 1, the rotor 23 is nested on a rotor support 22, and the planetary gear reducer is nested and installed inside the rotor support 22.

[0034] In the embodiment, the motor is an inner rotor type permanent magnet synchronous motor, the stator and the winding part are rigidly connected to the inside of the electric wheel shell 1 in the circumferential direction, and the stator winding length should be slightly smaller than the inside radial arrangement space of the electric wheel shell 1, so as to ensure the installability of the stator and the electromagnetic stability of the winding. In actual application, the design of the motor stator winding and the rotor should consider two aspects: one is whether the output external characteristic can meet the needs of the system; the other is whether the selection of the stator and the rotor can be integrated with the hub reduction electric wheel, that is, whether the size of the outside stator and winding exceeds the shell boundary, and whether the size of the inside rotor is too small to integrate the planetary gear mechanism or too large to receive a large centrifugal force and cause structural instability.

[0035] The planetary gear reducer comprises a sun gear 11, a planet gear 12, a planet gear ring 10, a planet carrier 13 and a planet carrier output shaft 14, the planet gear 12, the planet carrier 13, the sun gear 11 and the planet gear ring 10 are in floating connection in the axial direction, and the sun gear 11 is in radial anti-torsion connection with the rotor support 22 through the first spline 24. The hub flange plate 19 is sleeved on the planet carrier output shaft 14, the hub bearing unit 9 is assembled on the radial outer side of the planet carrier output shaft 14, and the rim 18 is installed on the axial outer side of the planet carrier output shaft 14.

[0036] The hub bearing unit 9 comprises a hub bearing seat 16 and a pair of back-to-back installed hub ball bearings 15, the inner side of the hub bearing unit 9 is in interference connection with the planet carrier output shaft 14, and the outer side of the hub bearing unit 9 is fixed on the shell end cover 2 in interference.

[0037] The drum brake comprises a brake bottom plate 8 and a brake drum 17, the brake bottom plate 8 is installed on the hub bearing seat 16 and is in hard connection with the surface of the shell end cover 2, as shown in the figure, Figure 2 The brake shoe 57, the brake cylinder 52, the parking rocker arm and the cable interface are integrally installed on the brake bottom plate 8, the brake drum 17 is installed on the hub flange plate 19, and the hub flange plate 19 is connected with the rim 18 through the embedded connecting bolt 20. The inner side of the hub flange plate 19 is sleeved with a magnetic ring, and the wheel speed sensor is installed on the brake bottom plate 8. In the scheme, the brake bottom plate 8 is hard connected with the surface of the shell end cover 2 to bear the brake torque and its own gravity. The magnetic ring and the electromagnetic wheel speed sensor are fixed on the hub flange plate 19 and the brake bottom plate 8 respectively, both of which are sleeved inside the brake drum 17 and relatively rotate, and are used for measuring the wheel speed. The electronic parking mechanism is internally integrated with a DC motor and a speed reduction mechanism, which is used for driving the parking brake cable to drive the parking rocker arm on the brake shoe, and the parking rocker arm provides the clamping force between the brake shoe and the brake drum, so as to realize the parking brake torque. Although the electronic parking mechanism is sleeved on the axle or integrated on the electric wheel shell, the brake cable is connected with the parking rocker arm on the brake bottom plate through the brake bottom plate in the direction of the shell, so as to realize the application of the parking force.

[0038] In the scheme, the drum brake is sleeved on the outer side of the hub bearing and the hub output shaft in the radial direction to save the axial space, and the magnetic ring and the wheel speed sensor are coaxially arranged with the drum brake and the wheel shaft to save the radial space. In addition to the mounting surface, the axial space should be left between the brake bottom plate and the shell to integrate the brake oil pipe and the exhaust screw. The brake bottom plate 8 of the drum brake is completely integrated with the shell, the exhaust screw and the brake oil way are integrated on the shell, and the brake cylinder and the brake shoe mounting surface are connected together in anti-torsion through the bolt, so as to transmit the brake torque to the shell.

[0039] The power and brake torque transmission path of the above-mentioned electric wheel assembly is as follows:

[0040] I. In the process of mechanical braking by drum brake device, friction torque is generated by the contact and friction between brake shoes installed on brake back plate and brake drum connected to the rim. The brake torque is transmitted to the rim through the connecting screws on the hub flange. In the non-braking working condition, the brake drum does not contact the brake shoes on the brake back plate in the radial direction; in the braking condition, the brake shoes are pushed against the inner wall of the brake drum under the action of brake cylinder oil pressure; in the parking brake condition, the brake shoes are pushed to contact and clamp the inner wall of the brake drum under the tension force transmitted from the brake cable to the brake arm, to achieve parking force.

[0041] II. In the process of implementing motor-driven driving, torque is transmitted from the motor rotor to the sun gear through the first spline between the rotor support and the sun gear, and then through the planetary gear train for speed reduction and torque increase, and then transmitted to the wheel shaft through the spline of the planetary carrier output shaft, and then transmitted to the rim and tire through the flange.

[0042] III. In the process of regenerative braking by electric motor, the transmission path of electric braking torque starts from the motor rotor, and then the braking torque is transmitted to the sun gear through the spline between the rotor support and the sun gear, and then through the planetary gear train for speed reduction and torque increase, and then transmitted to the wheel shaft through the spline of the planetary carrier output shaft, and then transmitted to the rim and tire through the flange.

[0043] Example I

[0044] In this embodiment, the electronic parking mechanism is set on the axle 33, as shown in Figure 3 The parking cable is a long brake cable 34, the EPB actuator 32 is connected to the long brake cable 34, and then enters the shell end cover 2 along the edge and is connected to the parking arm 35 of the brake back plate. The parking arm 35 is connected to the long brake cable 34 drawn out on the axle, and has a short stroke, but can provide sufficient shoe clamping force, thereby generating a large parking braking capacity. In addition, considering the mechanical loss of the parking cable during braking, in order to prolong the service life of the parking cable, a sleeve is provided on the parking cable, and grease is injected into the sleeve.

[0045] Example II

[0046] In this embodiment, the electronic parking mechanism is set on the electric wheel shell 1, as shown in Figure 4As shown, the parking cable specifically adopts a short brake cable 42, the EPB actuator output end 41 is connected with the short brake cable 42, and then enters along the edge of the electric wheel housing 1 and is connected to the cable interface of the brake bottom plate. The sleeve 43 is arranged on the short brake cable 42, and the sleeve fixing plate 44 and the brake cable guide fixing plate 45 are additionally arranged on the electric wheel housing 1 except for the corresponding hole design, so as to ensure that the short brake cable 42 can be accurately and reliably guided and connected to the brake bottom plate, so that the short brake cable 42 transmits the parking force to the parking rocker arm of the drum brake in the preset direction.

[0047] It should be noted that in actual application, if the electronic parking mechanism is mounted on the axle, the cable stroke is long and needs to pass through the axle, but the cable stroke inside the rim is easier to arrange; if the electronic parking mechanism is arranged on the electric wheel housing, the cable stroke is short and the transmission efficiency is high, but the arrangement of the cable is seriously affected by the space, which may be bent and worn, so the installation position of the EPB actuator on the electric wheel housing needs to be reasonably arranged according to the specific position of the parking rocker arm.

[0048] In summary, the present scheme can greatly reduce the axial size of the electric wheel assembly and improve the system integration degree through the high-integration arrangement of the hub motor, the planetary gear reducer, the hub bearing and the drum brake, and the parking cable. When arranging the electronic parking mechanism, the respective arrangement of the EPB actuator body and the parking cable is considered, and the internal space of the hub motor is fully utilized. Through the arrangement scheme, the conflict between the high integration of the electric wheel brake and the parking mechanism occupying volume is solved, and the parking efficiency of the drum brake mounted on the electric wheel is improved. The drum brake is installed between the housing end cover and the rim, and the axial space is relatively compact, while the radial size is relatively sufficient. The drum brake has a large radial size, which is convenient for implementing a large brake torque. The arrangement of the wheel speed sensor and the parking EPB cable fully utilizes the gap inside the brake bottom plate, brake shoe and hub flange plate, realizes the increase of integration degree, and integrates the brake at the wheel end. The low speed advantage makes the service life longer. In addition, considering the transmission process of the electronic parking device EPB tensioning force, the cable routing of the parking cable is reasonably designed, the integration of the EPB on the motor housing at the wheel end is realized, the loss in the transmission process is reduced, and the efficiency is improved; by punching holes on the motor housing, installing cable lubricating sleeve, cable fixing device and other means, the service life of the parking cable is increased, the mechanical loss is reduced, and the defects of the integrated difficulty and low transmission efficiency of the reduction hub motor electronic parking brake system are overcome.

[0049] The electric wheel system involved in the present scheme is currently mainly used for commercial vehicles with 16-inch rims, and can replace the mainstream centralized electric drive axle to realize the flattening of the vehicle floor. Compared with similar products, the weight is basically the same, but the axial space is more compact, and the connection space with the axle is more sufficient. Due to the more reasonable space arrangement, the specifications of the drive motor and the brake mounted are higher, and the overall drive / brake performance of the system is obviously improved compared with similar products.

Claims

1. A reduction hub electric wheel with integrated electronic parking mechanism, characterized in that: The invention comprises an electric wheel housing (1) and a housing end cover (2) connected thereto, wherein the electric wheel housing (1) is rigidly connected to a vehicle axle, the housing end cover (2) is connected to a wheel rim (18), a motor and a planetary gear reducer are nested inside the electric wheel housing (1), a drum brake and a wheel hub bearing unit (9) are nested inside the housing end cover (2), and the electronic parking mechanism is sleeved on the vehicle axle or the electric wheel housing (1) and connected to the drum brake via a parking cable.

2. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 1, characterized in that: The motor comprises a stator (21) and a rotor (23), wherein the stator (21) is nested inside the electric wheel housing (1), the rotor (23) is nested on the rotor bracket (22), and the planetary gear reducer is nested inside the rotor bracket (22).

3. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 2, characterized in that: The planetary gear reducer comprises a sun gear (11), planetary gears (12), a planetary gear ring (10), a planetary carrier (13) and a planetary carrier output shaft (14); the planetary gears (12), the planetary carrier (13), the sun gear (11) and the planetary gear ring (10) are kept in floating connection in the axial direction; the sun gear (11) is connected to the rotor support (22) in a radial torsion-resistant manner via a first spline.

4. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 3, characterized in that: A hub flange (19) is sleeved on the planetary carrier output shaft (14), the hub bearing unit (9) is assembled on the radial outer side of the planetary carrier output shaft (14), and the rim (18) is installed on the axial outer side of the planetary carrier output shaft (14).

5. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 4, characterized in that: The hub bearing unit (9) comprises a hub bearing seat (16) and a pair of hub ball bearings (15) mounted back to back. The inner side of the hub bearing unit (9) is connected to the planetary carrier output shaft (14) in an interference fit manner, and the outer side of the hub bearing unit (9) is fixed to the housing end cover (2) in an interference fit manner.

6. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 5, characterized in that: The drum brake comprises a brake base plate (8) and a brake drum (17); the brake base plate (8) is mounted on a wheel hub bearing seat (16) and is rigidly connected to the surface of a housing end cover (2); a brake shoe, a brake wheel cylinder, a parking rocker arm and a cable interface are integrally mounted on the brake base plate (8); The brake drum (17) is mounted on a wheel hub flange (19), and the wheel hub flange (19) is connected to the wheel rim (18) via pre-buried connecting bolts.

7. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 6, characterized in that: The inner side of the wheel hub flange (19) is sleeved with a magnetic ring, and the brake base plate (8) is equipped with a wheel speed sensor.

8. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 6, characterized in that: When the electronic parking mechanism is sleeved on the vehicle axle, the parking cable is specifically a long brake cable, which is passed through the edge of the housing end cover (2) and connected to the cable interface of the brake base plate (8).

9. The reduction hub electric wheel with integrated electronic parking mechanism according to claim 6, characterized in that: When the electronic parking mechanism is sleeved on the electric wheel housing (1), the parking cable is specifically a short brake cable, which penetrates along the edge of the electric wheel housing (1) and is connected to the cable interface of the brake base plate (8).

10. The reduction hub electric wheel with integrated electronic parking mechanism according to any one of claims 1 to 9, characterized in that: The parking cable is provided with a sleeve, and grease is injected into the sleeve.

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