Rear wheel driving assembly of electric golf cart

Abstract

The invention discloses a rear wheel driving assembly of an electric golf cart, which belongs to the technical field of electric propulsion devices.The rear wheel driving assembly of the electric golf cart comprises a motor and a motor shaft, and the motor shaft provides rotation driving force through a bevel gear; the protective shell comprises a shell body, the motor is fixedly connected with the shell body through bolts, the motor shaft is rotationally installed in the shell body, and an installation shell is fixedly installed at the end, away from the motor, of the shell body and is parallel to the motor shaft. High-torque output is achieved in a limited space through the two-stage parallel shaft speed reducing mechanism, a bevel gear on the output shaft of the motor is meshed with a first transmission gear on the middle shaft, the middle shaft synchronously drives a second transmission gear to drive an outer gear ring of the differential mechanism, and the requirement for driving force of complex road conditions such as fluctuating grassland is effectively met; the middle shaft is of a two-end full-supporting structure and is rigidly installed in thick-wall bearing seats on the two sides of the shell through ball bearings, a high-rigidity simply-supported beam layout is formed, and the radial bearing capacity is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of electric propulsion technology, specifically relating to a rear-wheel drive assembly for an electric golf cart. Background Technology

[0002] Electric golf carts are low-speed, environmentally friendly electric vehicles designed specifically for golf courses and short-distance commuting. They feature zero emissions, low noise, flexible handling, and moderate range. Utilizing an electric drive system, they are compact, comfortable to ride, and widely used for golf course transportation, scenic area shuttles, community patrols, and other scenarios, combining practicality with the concept of green travel.

[0003] In the current electric golf cart market, the design of rear-wheel drive assemblies faces multiple challenges. Traditional drive systems often struggle to balance a compact spatial layout with efficient power transmission performance, especially when driving on complex terrains such as undulating grass, mud, or uneven surfaces. This requires the drive system to not only provide sufficient torque output but also possess excellent control capabilities. Furthermore, the axial impact force generated during motor start-up and shutdown can easily cause additional radial loads on intermediate transmission components, leading to premature bearing damage and affecting the overall service life and reliability of the vehicle. Therefore, designing a rear-wheel drive assembly that can achieve efficient power transmission within a limited space while effectively suppressing vibration and extending the service life of key components has become an urgent problem to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an electric golf cart rear-wheel drive assembly.

[0005] The technical solution adopted to solve the above technical problems is: An electric golf cart rear-wheel drive assembly includes: An electric motor, including a motor shaft, wherein the motor shaft provides rotational driving force via a helical gear; A protective housing includes a housing, wherein the motor is fixedly connected to the housing by bolts, the motor shaft is rotatably mounted in the housing, and a mounting housing is fixedly mounted on the end of the housing away from the motor and parallel to the motor shaft; The coupling includes an intermediate shaft and a differential. The intermediate shaft is rotatably supported at both ends by ball bearings. A first transmission gear and a second transmission gear are disposed in the intermediate shaft. The second transmission gear meshes with a helical gear. The differential includes a frame. An external gear ring that meshes with the first transmission gear is fixedly installed on the outside of the frame. Two output gears are symmetrically installed on the frame at the rotation axis of the external gear ring. The two output gears are connected by bevel gear meshing. A damper is provided in the middle section of the output gear. The damper can change the rotational resistance of the output gear. A wheel axle is rotatably mounted in a mounting housing via bearings. One end of the wheel axle located inside the housing has a spline head, and the wheel axle is engaged with the spline hole of the output gear through the spline head. The system consists of a motor that drives the motor shaft to rotate at high speed, a helical gear that drives a second transmission gear to reduce the speed and rotate the intermediate shaft, and a first transmission gear that rotates synchronously with the intermediate shaft. This rotation, via an external gear ring, drives the frame to rotate at a reduced speed, which in turn drives the tires to rotate via the wheel axles. This two-stage speed reduction ensures a large output torque to adapt to the driving environment of undulating grassy terrain. The wheel axles are encased and protected to prevent direct impact from uneven ground. The intermediate shaft, as a reduction component, is parallel to the motor shaft and wheel axles with a radial distance to accommodate the limited space of the housing. This results in a small overall height after assembly, while increasing the distance from the top to the frame, reducing the impact on the tires and frame. The impact of the damping stroke between the two shafts is reduced, but this will cause the intermediate shaft to be subjected to a large radial force from the motor shaft and the differential. At this time, bearings are used to limit and support both ends of the intermediate shaft. Compared with the conventional single bearing design of the cantilever shaft, the radial stability is higher and the bearing damage and abnormal noise are avoided. The output gear drives the two wheel shafts to rotate independently to form differential drive. When high-speed steering or one side of the tire slips, the damper on the same side applies frictional resistance to the output gear to suppress excessive speed difference that may cause steering fishtailing or drive wheel slippage. The two dampers are fixed to the housing to center and limit the differential, preventing the differential from axial movement.

[0006] Furthermore, the motor shaft includes a drive shaft, which is connected to the motor via a coupling. Tapered roller bearings are provided at both ends of the helical gear on the drive shaft, and the tapered roller bearings are connected to the housing.

[0007] Through the above technical solution, the drive shaft is designed as a solid shaft and is mounted on the upper part of the inner side of the housing by two tapered roller bearings. The helical gear is placed in the middle section of the drive shaft. The tapered roller bearings are located on both sides of the helical gear to balance the force on the drive shaft. The helical teeth of the helical gear and the transmission gear can convert part of the radial reaction force into axial reaction force. Moreover, the high-speed rotation reduces the radial force between the intermediate shaft and the motor shaft and reduces the radial load on the bearings. The two tapered roller bearings can simultaneously withstand large radial and axial loads, which is compatible with the force situation of the drive shaft. Furthermore, the tapered roller bearings can change the relative axial position of the inner and outer rings by adjusting the nuts or shims, thereby controlling the preload of the drive shaft and stabilizing the meshing clearance of the helical gear and the transmission gear, avoiding abnormal noise and play caused by the increase of the gear key clearance over a long period of use.

[0008] Furthermore, the intermediate shaft includes a shaft body, the thickness of the second transmission gear is twice the thickness of the first transmission gear, the first transmission gear and the external gear ring are connected by a spur key, and the first transmission gear is centrally located in the middle of the shaft body.

[0009] Through the above technical solution, the shaft body is made of high-strength steel and is fixed to transmission gear one and transmission gear two respectively, making the position between transmission gear one and transmission gear two more secure. The thickness of transmission gear two increases the meshing contact surface and avoids deformation of the contact surface. The thinner thickness of transmission gear two reduces the lateral space occupied by transmission gear one and transmission gear two in the housing, thereby reducing the width of the housing and reducing the overall mass and volume of the housing and internal components. The meshing method of transmission gear one and the spur key of the external gear ring avoids the differential being subjected to excessive axial force transmitted from transmission gear one.

[0010] Furthermore, the motor shaft includes a second drive shaft and a coaxial rotating sleeve coaxially mounted. The second drive shaft is assembled and connected to the motor via a coupling. A stabilizer is provided at the end of the second drive shaft away from the motor. The stabilizer is located outside the housing. The second drive shaft and the coaxial rotating sleeve are assembled and connected to the stabilizer via a first meshing member and a second meshing member, respectively. The stabilizer enables damped torsion between the second drive shaft and the coaxial rotating sleeve.

[0011] Through the above technical solution, the structure of the motor shaft is optimized. The second drive shaft is connected to the motor, and the coaxial sleeve is connected to the helical gear. A stabilizer is set between the second drive shaft and the coaxial sleeve. The axial impact generated during the start-up, stop, acceleration and deceleration of the motor is absorbed and converted by the stabilizer, avoiding transmission to the intermediate shaft through the meshing of the helical gear. This effectively avoids the rapid damage of the bearings at both ends of the intermediate shaft caused by the combined action of high radial force and bidirectional axial force.

[0012] Furthermore, the stabilizer includes a fixed shell, which is fixedly connected to the housing by bolts. The fixed shell houses a coaxially arranged active disk and a driven disk. A torque assembly is provided between the active disk and the driven disk. The counterweight disk is fixedly connected to the active disk.

[0013] The above technical solution discloses a specific configuration of a stabilizer. The active disc engages with a first engagement component via a spline groove, and the driven disc engages with a second engagement component via a spline groove. This allows for quick horizontal insertion and removal for assembly. After assembly, the fixing shell is secured to the housing with bolts to ensure stable engagement. Simultaneously, the counterweight disc increases the counterweight, enhancing the rotational stability of the second active shaft. The torque assembly transmits torsional driving force, causing the active disc to rotate the driven disc. When the active disc vibrates axially, the torque assembly can be stretched axially and reset under its own elasticity. During frequent motor speed changes, this significantly reduces the axial force directly transmitted to the driven disc, achieving axial vibration isolation and protecting the stable operation of the intermediate shaft.

[0014] Furthermore, the damper includes a housing, a resistance source, and a relay ring. The relay ring is coaxially sleeved and fixed on the outer side of the middle section of the output gear. The housing is sleeved on the outer side of the relay ring. The resistance source applies variable pressure to the friction ring of the relay ring along the axial direction. The housing is provided with a plane bearing on the side of the relay ring away from the resistance source. The outer circumference of the relay ring is provided with a scale groove. The housing is provided with a Hall sensor directly opposite the scale groove.

[0015] The above technical solution discloses a specific configuration of a damper. The housing is fitted onto the outside of the output gear, and the lower end of the housing is fixed to the lower inner wall of the outer shell. This can support the differential and provide centering and limiting. When it is necessary to decelerate the output gear, because the relay ring and the output gear are fixed, when the resistance source squeezes the friction ring of the relay ring, the friction increases the rotational resistance of the output gear, thereby reducing the speed of the output gear. Meanwhile, the plane bearing provides support from the other side to prevent the output gear from moving axially. At the same time, the Hall sensor with the scale groove can generate a pulse signal. The pulse signal is converted into a digital signal by the peripheral control module, which can obtain the speed of the output gear in real time. This allows for precise control of the speed difference between the two output gears, significantly reducing the risk of steering fishtailing and getting stuck.

[0016] Furthermore, the resistance source includes a contact ring, the housing has a movable cavity for the contact ring to slide along the output gear axis, the outer circumferential wall of the contact ring slides and seals with the inner wall of the movable cavity, a straight sliding sleeve is provided between the contact ring and the housing, the housing has a straight tube at the side wall of the movable cavity, the straight tube extends to the bottom of the inner side of the housing, and a pump is connected in series on the straight tube.

[0017] The above technical solution discloses a specific design for a resistance source. To apply pressure to the friction ring, a contact ring is provided. When the pump is working, gear oil inside the housing can be directly pumped into the moving chamber as the transmission medium. The outer circumference of the contact ring slides and seals against the inner wall of the moving chamber, preventing gear oil from entering the gap between the contact ring and the friction ring. Hydraulic pressure then forces the contact ring against the friction ring. The position of the contact ring is limited by a linear sliding sleeve, preventing it from rotating around the output gear, thus allowing relative sliding between it and the friction ring. This achieves frictional speed reduction. Furthermore, the pump uses a metering pump or is used in conjunction with a flow meter to control the pressure applied to the contact ring, making the pressure applied to the friction ring controllable and allowing for more flexible control of the output gear's speed.

[0018] Furthermore, the resistance source includes an electromagnetic ring, the housing has a movable cavity for the electromagnetic ring to slide along the output gear axis, the electromagnetic ring has a lug on its circumferential sidewall, the housing has a straight groove corresponding to the lug, and the relay ring is a permanent magnet.

[0019] The above technical solution discloses a specific design of a resistance source and a hydraulic control method. However, this method requires numerous control and execution components, as well as controlling the surface finish of the contact surfaces for sliding sealing. This results in high processing precision and maintenance costs. In contrast, using an electromagnetic ring instead of a contact ring allows for direct energization, generating magnetism and attracting the electromagnetic ring to the friction ring surface. The lugs prevent the electromagnetic ring from rotating, allowing it to slide against the friction ring and quickly generate frictional resistance. Controlling the input current changes the magnetic force. This method requires fewer execution components, lowers assembly precision requirements, and makes controlling the output gear speed more convenient. Furthermore, the relay ring uses a permanent magnet material, increasing the attraction force and adapting to greater frictional forces. For example, one output gear can be completely stopped, using only the other output gear to provide rotational drive for single-wheel escape in harsh environments. When it's not necessary to reduce the output gear speed, the electromagnetic ring can be reverse-energized, causing the electromagnetic ring to move away from the friction ring through magnetic repulsion, avoiding the loss of driving force caused by continuous contact between the electromagnetic ring and the friction ring during normal operation.

[0020] Furthermore, the frame adopts a hollow square frame structure, and the inner wall of the outer toothed ring is provided with a support block. The support block is fixedly connected to the frame, and the support block has a notch facing the opening of the frame.

[0021] Through the above technical solution, in order to ensure the stable installation of the external gear ring, the inner surface of the external gear ring is arc-shaped, and there are few contact points with the straight edge of the frame, which makes direct welding insufficient. However, by using a support block as a relay, the weldable area at the contact position can be increased. In addition, the straight surface at the notch of the support block can push or swing the gear oil below upward along the straight surface when the external gear ring rotates, so that the gear oil can flush the contact surface of the bevel gear and the output gear, and actively flush and cool it down, ensuring that the temperature of the bevel gear and the output gear is controllable when the speed difference between the two gear shafts is large.

[0022] Furthermore, a cantilever is connected to the lower part of the mounting housing via a rubber pad, and a shock absorber is installed on the top of the mounting housing. The cantilever and the shock absorber are assembled and connected to the vehicle frame.

[0023] With the above technical solution, the lower end of the cantilever is flexibly connected to the chassis via foot pads and mounting shell, while the upper end of the cantilever is connected to the chassis. Combined with the shock absorber design, this can prevent excessive tire vibration from being transmitted to the chassis, thereby improving the vehicle's ride comfort.

[0024] The beneficial effects of this invention are as follows: (1) The present invention achieves high torque output in a limited space through a two-stage parallel shaft reduction mechanism: the helical gear on the motor output shaft meshes with the first transmission gear on the intermediate shaft, and the intermediate shaft synchronously drives the second transmission gear to drive the differential outer gear ring, effectively meeting the driving force requirements of complex road conditions such as undulating grass. The intermediate shaft adopts a fully supported structure at both ends and is rigidly installed in the thick-walled bearing seats on both sides of the housing by ball bearings, forming a high-rigidity simply supported beam layout, which significantly improves the radial bearing capacity and avoids early wear, abnormal noise or even failure caused by the concentrated force of traditional cantilever single bearings. (2) The present invention integrates an adjustable damping device on the output gears on both sides of the differential. The device applies controllable pressure to the friction ring through a sleeve fixed in the housing, dynamically adjusting the rotational resistance of the output gear. When turning at high speed or when one tire slips, it automatically suppresses excessive wheel speed difference to prevent tail-swing or the drive wheel getting stuck. At the same time, the left and right damping devices are symmetrically arranged and also serve as the axial limiting structure of the differential, effectively preventing it from moving under alternating loads. The axle is fully enclosed by the mounting shell that extends from the housing, with only the outer end exposed to connect the wheel, avoiding direct collision with ground obstacles such as gravel and grass roots. The lower part of the mounting shell is connected to the cantilever bracket through an elastic rubber pad, and the top is equipped with a shock absorber. Both are assembled with the frame, greatly isolating the road vibration from being transmitted to the vehicle body and significantly improving driving comfort. (3) This invention adds an external stabilizer at the motor output end. The stabilizer connects the inner and outer transmission components through a torque component, converting axial vibration energy into elastic deformation and dissipating it. This effectively blocks the impact from being transmitted to the intermediate shaft through gear meshing, protecting the core transmission components. The overall layout adopts a staggered parallel arrangement, making the drive assembly compact in the height direction and increasing the distance from the top of the housing to the frame, thus reserving sufficient damping stroke for the rear suspension system. Through multi-dimensional structural collaborative innovation, this invention systematically solves the shortcomings of traditional electric golf cart drive assemblies in terms of load-bearing capacity, operational durability, driving safety, and ride comfort. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the housing of the present invention; Figure 3 This is a schematic diagram showing the positions of the drive shaft, intermediate shaft, differential, and damper of the present invention. Figure 1 ; Figure 4 This is a schematic diagram showing the positions of the drive shaft, intermediate shaft, differential, and damper of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the structure between the differential and the damper of the present invention; Figure 6 This is a schematic diagram of the assembly between the output gear and the damper of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of the assembly between the output gear and the damper of the present invention. Figure 2 ; Figure 8 This is a schematic diagram showing the state in which a stabilizer is added between the second drive shaft and the intermediate shaft of the present invention; Figure 9 This is a schematic diagram showing the positions of the second drive shaft, the intermediate shaft, and the stabilizer in this invention; Figure 10 This is a schematic diagram of the structure between the second drive shaft and the stabilizer of the present invention.

[0026] Reference numerals: 1. Motor; 2. Housing; 21. Half-shell one; 22. Half-shell two; 3. Axle; 4. Mounting housing; 41. Cantilever; 42. Shock absorber; 5. Stabilizer; 51. Fixed housing; 52. Driven disc; 521. Counterweight disc; 53. Driven disc; 54. Torque assembly; 6. Motor shaft; 61. Driven shaft one; 62. Helical gear; 63. Driven shaft two; 631. Meshing part one; 64. Coaxial rotating sleeve; 641. Meshing part two; 7. Intermediate shaft; 71. Shaft body; 72. Transmission gear one; 73. 74. Transmission gear; 8. Ball bearing; 9. Differential; 81. Frame; 811. Support block; 82. External gear ring; 83. Bevel gear; 84. Output gear; 841. Spline hole; 9. Damper; 91. Sleeve; 911. Straight groove; 92. Pump; 921. Straight pipe; 93. Moving chamber; 94. Relay ring; 941. Friction ring; 942. Scale groove; 943. Hall sensor; 95. Contact ring; 951. Linear sleeve; 96. Surface bearing; 97. Electromagnetic ring; 971. Support lug. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] like Figure 1 - Figure 10 As shown, this embodiment provides a rear-wheel drive assembly for an electric golf cart, including a motor 1, a protective shell, a coupling, a wheel axle 3, and a damping structure.

[0029] Reference Figure 1The motor 1 is fixedly mounted on the upper rear of the vehicle frame, with its output end facing the side of the vehicle. The motor 1 has a motor shaft 6 arranged laterally along the vehicle. A helical gear 62 is fixedly fitted at the end of the motor shaft 6 (the end furthest from the motor body) to transmit rotational driving force. The protective housing includes a housing 2 and a mounting housing 4 located at its lower end, which are rigidly connected by fasteners. The housing 2 is formed by combining half-shell 1 21 and half-shell 22. Its rear side is tightly fitted and fixed to the flange face of the motor 1 housing by multiple circumferentially distributed bolts, ensuring a rigid and reliable power transmission path. The motor shaft 6 passes through bearing holes in the sidewall of half-shell 21 and is rotatably supported inside the housing 2 by deep groove ball bearings. The mounting housing 4 extends axially from the lower end of the housing 2 along the motor shaft 6, with its axis parallel to the motor shaft 6 and spaced apart in the height direction, to accommodate and protect the wheel axle 3.

[0030] Reference Figure 2 The coupling is located in the central area inside the housing 2, and includes an intermediate shaft 7 and a differential 8. The intermediate shaft 7 is arranged laterally along the vehicle, with its axis parallel to the motor shaft 6 and wheel axles 3, but lower than the motor shaft 6 in the vertical direction, and centered between the left and right wheel axles 3 in the horizontal direction, to accommodate the compact layout inside the housing 2. The two ends of the intermediate shaft 7 are rigidly supported in the bearing seat holes on both sides of the housing 2 by a pair of ball bearings 74 (preferably deep groove ball bearings with seals), forming a full-span double-support structure, which effectively resists the radial load from gear meshing. A transmission gear 1 72 and a transmission gear 2 73 are coaxially fixed in the middle of the intermediate shaft 7, wherein the transmission gear 2 73 is away from the motor side and meshes with the helical gear 62 on the motor shaft 6; the transmission gear 1 72 is close to the differential 8 side and meshes with the outer gear ring 82 of the differential 8.

[0031] Please refer to Figure 2 The differential 8 is located at the lower center of the housing 2. Its frame 81 is a square ring structure with an external gear ring 82 integrally formed on its outer circumference, which meshes with the transmission gear 72. Inside the frame 81, two output gears 84 are symmetrically mounted along its axis of rotation. The axes of the two output gears 84 are collinear with the left and right axles 3, respectively. The two output gears 84 mesh with each other through a pair of bevel gears 83, forming a standard planetary differential mechanism. A damper 9 is integrated in the middle section of the hub of each output gear 84. The outer ring of the damper 9 is rigidly fixed to the mounting platform on the inner wall of the housing 2 by screws, and the inner ring applies frictional resistance to the output gear 84. This provides controllable rotational resistance while applying axial bidirectional limiting to the entire differential 8, preventing it from axially shifting under high torque impact.

[0032] Reference Figure 1The axle 3 consists of two solid axles arranged symmetrically on the left and right. The inner end of each axle 3 (i.e., the end closest to the center of the vehicle) is machined with an external spline, which is inserted into the spline hole 841 at the center of the corresponding output gear 84 to achieve torque transmission. The outer end of the axle 3 extends out of the mounting shell 4 and connects to the wheel hub. The axle 3 is completely enclosed by the mounting shell 4. That is, the mounting shell 4 extends horizontally from the end face of the front shell 2, completely covering the bearing mounting section and spline connection section of the axle 3, with only the outer end exposed for connecting the tire. This effectively prevents the axle 3 from being directly hit or scratched by gravel, grass roots or raised terrain when the vehicle is driving on undulating grass or potholes.

[0033] The working principle of this embodiment is as follows: After motor 1 starts, motor shaft 6 rotates at high speed, driving helical gear 62 to drive transmission gear 73, causing intermediate shaft 7 to rotate at a reduced speed. Since transmission gear 72 is fixed to intermediate shaft 7, it synchronously drives external gear ring 82 and frame 81 to rotate, completing the second stage of reduction. Power is distributed to left and right output gears 84 via bevel gear 83, and then connected to drive wheel axle 3 via spline, ultimately driving the rear wheels to rotate. This two-stage parallel shaft plus differential 8 combination structure is arranged in a compressed manner in the height direction—intermediate shaft 7 is located below motor shaft 6, and wheel axle 3 is located even lower, which significantly increases the distance from the top of the drive assembly (i.e., the upper surface of housing 2) to the frame mounting surface, providing sufficient shock absorption travel for the rear suspension system and preventing contact with the frame during bumps. Since the intermediate shaft 7 simultaneously bears the downward radial force generated by the meshing of the helical gear 62 (from the motor shaft 6) and the upward radial force generated by the reaction of the external gear ring 82 (from the differential 8), it is extremely easy to bend and deform if a single-end support is used, leading to uneven bearing wear. In this embodiment, both ends of the intermediate shaft 7 are rigidly supported by ball bearings 74 in the thick-walled bearing seats on both sides of the housing 2, forming a high-rigidity simply supported beam structure, which greatly improves the radial load-bearing stability and effectively suppresses early bearing fatigue, abnormal noise, and even seizure. When a vehicle is cornering at high speed or one wheel is stuck in mud or grass and slips, the differential 8 naturally amplifies the speed difference between the two wheels. At this time, the output gear 84 on the slipping side rotates rapidly, and its integrated damper 9 can controllably generate greater frictional resistance, limiting excessive spinning on that side. At the same time, the two dampers 9 are symmetrically fixed to the inner wall of the housing 2, together forming the axial positioning reference of the differential 8, preventing the frame 81 from moving back and forth under alternating torque, and avoiding impact noise caused by sudden changes in gear meshing clearance. Thus, while ensuring the differential function, it significantly improves traction stability on wet or uneven roads, reduces the risk of fishtailing, and enhances driving safety.

[0034] In a further embodiment, refer to Figure 3 and Figure 4The motor shaft 6 includes a drive shaft 61, which is connected to the motor 1 via a coupling. Tapered roller bearings are located at both ends of the helical gear 62 on the drive shaft 61. These tapered roller bearings are connected to the housing 2. The drive shaft 61 is designed as a solid shaft and is supported on the upper inner side of the housing 2 by two tapered roller bearings. The helical gear 62 is positioned in the middle of the drive shaft 61. The tapered roller bearings on both sides of the helical gear 62 ensure balanced force distribution on the drive shaft 61. The helical teeth of the helical gear 62 and the transmission gear 73 can convert part of the radial reaction force into… The axial reaction force, and the high-speed rotation, thereby reducing the radial force between the intermediate shaft 7 and the motor shaft 6, reducing the radial load on the bearings. The two tapered roller bearings can simultaneously withstand large radial and axial loads, which are adapted to the stress conditions of the drive shaft 61. Furthermore, the tapered roller bearings can change the relative axial position of the inner and outer rings by adjusting the nuts or shims, thereby controlling the preload of the drive shaft 61, controlling the meshing clearance of the helical gear 62 and the transmission gear 73 to stabilize, and avoiding abnormal noise and play caused by the increase of the gear key clearance after long-term use.

[0035] In a further embodiment, refer to Figure 3 and Figure 4 The intermediate shaft 7 includes a shaft body 71. The thickness of the second transmission gear 73 is twice the thickness of the first transmission gear 72. The first transmission gear 72 and the external gear ring 82 are connected by a spur key. The first transmission gear 72 is centrally located in the middle of the shaft body 71. The shaft body 71 is made of high-strength steel and is fixed to the first transmission gear 72 and the second transmission gear 73 respectively, making the position between the first transmission gear 72 and the second transmission gear 73 more secure. The thickness of the second transmission gear 73 increases the meshing contact surface and avoids deformation of the contact surface. The thinner thickness of the second transmission gear 73 reduces the lateral space occupied by the first transmission gear 72 and the second transmission gear 73 in the housing 2, thereby reducing the width of the housing 2 and reducing the overall mass and volume of the housing 2 and internal components. The spur key meshing method between the first transmission gear 72 and the external gear ring 82 avoids the differential 8 from being subjected to excessive axial force transmitted by the first transmission gear 72.

[0036] In a further embodiment, the structure of the motor shaft 6 is optimized, referring to... Figure 8 , Figure 9 and Figure 10The motor shaft 6 includes a coaxially fitted drive shaft 63 and a coaxial rotating sleeve 64. The drive shaft 63 is assembled and connected to the motor 1 via a coupling. A stabilizer 5 is provided at the end of the drive shaft 63 away from the motor 1. The stabilizer 5 is located outside the housing 2. The drive shaft 63 and the coaxial rotating sleeve 64 are assembled and connected to the stabilizer 5 via meshing parts 631 and 641, respectively. The stabilizer 5 enables damped torsion between the drive shaft 63 and the coaxial rotating sleeve 64. The drive shaft 63 is connected to the motor 1, and the coaxial rotating sleeve 64 is connected to the helical gear 62. The stabilizer 5 is set between the drive shaft 63 and the coaxial rotating sleeve 64. The axial impact generated during the start-up, stop, acceleration and deceleration of the motor 1 is absorbed and converted by the stabilizer 5, avoiding transmission to the intermediate shaft 7 through the meshing of the helical gear 62. This effectively avoids the rapid damage of the bearings at both ends of the intermediate shaft 7 caused by the combined action of high radial force and bidirectional axial force.

[0037] In a further embodiment, a specific configuration of the stabilizer 5 is disclosed, referring to... Figure 10 The stabilizer 5 includes a fixed housing 51, which is fixedly connected to the housing 2 by bolts. The fixed housing 51 houses a coaxially arranged active disk 52 and driven disk 53. A torque assembly 54 is provided between the active disk 52 and the driven disk 53. A counterweight disk 521 is fixedly connected to the active disk 52. The active disk 52 engages with engagement member 631 via a spline groove, and the driven disk 53 engages with engagement member 641 via a spline groove. This allows for quick horizontal insertion and removal during assembly. After assembly, the fixed housing 51 is fixed to the housing by bolts. 2. This ensures stable meshing. At the same time, the counterweight plate 521 can increase the counterweight, making the rotational stability of the second drive shaft 63 stronger. The torque component 54 can transmit torsional driving force, causing the drive plate 52 to drive the driven plate 53 to rotate. When the drive plate 52 vibrates axially, the torque component 54 can be stretched axially and reset under its own elasticity. When the motor 1 frequently changes speed, it greatly reduces the axial force directly transmitted to the driven plate 53, realizes the isolation of axial vibration, and protects the stable operation of the intermediate shaft 7.

[0038] In a further embodiment, a specific configuration of the damper 9 is disclosed, referring to... Figure 5 - Figure 7The damper 9 includes a housing 91, a resistance source, and a relay ring 94. The relay ring 94 is coaxially sleeved and fixed on the outer side of the middle section of the output gear 84. The housing 91 is sleeved on the outer side of the relay ring 94. The resistance source applies variable pressure to the friction ring 941 of the relay ring 94 along the axial direction. A plane bearing 96 is provided on the side of the housing 91 away from the resistance source. A scale groove 942 is provided on the outer circumference of the relay ring 94. A Hall sensor 943 is provided on the housing 91 opposite to the scale groove 942. The housing 91 is sleeved on the outer side of the output gear 84. The lower end of the housing 91 is fixed on the lower inner wall of the housing 2, which can support the differential 8 and perform centering and limiting. When the output gear 84 is decelerated, since the relay ring 94 and the output gear 84 are fixed, when the resistance source squeezes the friction ring 941 of the relay ring 94, the friction increases the rotational resistance of the output gear 84, thereby reducing the speed of the output gear 84. Meanwhile, the plane bearing 96 provides support from the other side to prevent the output gear 84 from moving axially. At the same time, the Hall sensor 943, in conjunction with the scale groove 942, can generate a pulse signal. The pulse signal is converted into a digital signal by the peripheral control module, which can obtain the speed of the output gear 84 in real time. This allows for precise control of the speed difference between the two output gears 84, significantly reducing the risk of steering fishtailing and getting stuck.

[0039] In a further embodiment, a specific design of a resistance source is disclosed, referring to... Figure 6 The resistance source includes a contact ring 95. The housing 91 has a movable cavity 93 for the contact ring 95 to slide axially along the output gear 84. The outer circumferential wall of the contact ring 95 slides and seals against the inner wall of the movable cavity 93. A linear sliding sleeve 951 is provided between the contact ring 95 and the housing 91. A straight pipe 921 is provided on the side wall of the movable cavity 93 of the housing 91, extending to the bottom of the inner side of the housing 2. A pump 92 is connected in series on the straight pipe 921. A contact ring 95 is provided to apply pressure to the friction ring 941. When the pump 92 is working, the gear oil in the housing 2 can be directly pumped into the movable cavity 93 as the transmission medium. The outer circumference of ring 95 slides and seals against the inner wall of the movable cavity 93, preventing gear oil from entering the gap between contact ring 95 and friction ring 941. Hydraulic pressure then forces contact ring 95 against friction ring 941. The position of contact ring 95 is limited by linear sleeve 951, preventing it from rotating around output gear 84. This allows relative sliding between contact ring 95 and friction ring 941, achieving frictional speed reduction. Furthermore, pump 92, using a metering pump or a flow meter, can control the pressure applied to contact ring 95, making the pressure applied to friction ring 941 controllable and allowing for more flexible control of the output gear 84's rotational speed.

[0040] In a further embodiment, a specific design of a resistance source is disclosed, referring to... Figure 7The resistance source includes an electromagnetic ring 97. The housing 91 has a movable cavity 93 for the electromagnetic ring 97 to slide along the axial direction of the output gear 84. The circumferential side wall of the electromagnetic ring 97 has a support lug 971, and the housing 91 has a straight groove 911 corresponding to the support lug 971. The relay ring 94 uses a permanent magnet and is hydraulically controlled. This requires many control and execution components, and also requires controlling the smoothness of the contact surface for sliding sealing. The machining precision requirements are high, and the maintenance cost is high. However, by using the electromagnetic ring 97 instead of the contact ring 95, it can generate magnetism directly when energized and be attracted to the surface of the friction ring 941. The support lug 971 prevents the electromagnetic ring 97 from rotating, which allows the electromagnetic ring 97 and the friction ring 941 to slide, quickly generating frictional resistance. By controlling the magnitude of the input current, the magnitude of the magnetic force can be changed. Fewer actuators are required, lower assembly precision is needed, and the speed control of the output gear 84 is more convenient. Furthermore, the relay ring 94 is made of permanent magnet material, which can increase the attraction force and thus adapt to the greater friction force requirements. For example, one side of the output gear 84 can be completely stopped, and only the other side of the output gear 84 can be used to output rotational driving force for single-wheel escape in harsh environments. When it is not necessary to reduce the speed of the output gear 84, the electromagnetic ring 97 can be reverse-energized, and the magnetic repulsion of the relay ring 94 can keep the electromagnetic ring 97 away from the friction ring 941, which can avoid the loss of driving force caused by the continuous contact between the electromagnetic ring 97 and the friction ring 941 during normal operation.

[0041] In a further embodiment, refer to Figure 4 The frame 81 adopts a hollow square frame structure. The inner wall of the outer gear ring 82 is provided with a support block 811, which is fixedly connected to the frame 81. The support block 811 has a notch facing the opening of the frame 81. In order to ensure the stable installation of the outer gear ring 82, the inner surface of the outer gear ring 82 is arc-shaped, and there are few contact points with the straight edge of the frame 81. Direct welding is not strong enough. By using the support block 811 as a relay, the weldable area at the contact position can be increased. In addition, the straight surface at the notch of the support block 811 can push or swing the gear oil below upward along the straight surface when the outer gear ring 82 rotates, so that the gear oil can flush the contact surface of the bevel gear 83 and the output gear 84, and perform active flushing and cooling, ensuring that the temperature of the bevel gear 83 and the output gear 84 is controllable when the speed difference between the two gear shafts 3 is large.

[0042] In a further embodiment, refer to Figure 1 The lower part of the mounting shell 4 is connected to the suspension arm 41 via a rubber pad, and the top of the mounting shell 4 is equipped with a shock absorber 42. The suspension arm 41 and the shock absorber 42 are assembled and connected to the frame. The lower end of the suspension arm 41 is flexibly connected to the mounting shell 4 via a foot pad, and the upper end of the suspension arm 41 is connected to the frame. With the design of the shock absorber 42, excessive tire vibration can be avoided from being transmitted to the frame, thus improving the driving comfort of the vehicle.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A rear-wheel drive assembly for an electric golf cart, characterized in that, include: The motor (1) includes a motor shaft (6) which provides rotational driving force through a helical gear (62); The protective shell includes a housing (2), the motor (1) is fixedly connected to the housing (2) by bolts, the motor shaft (6) is rotatably installed in the housing (2), and a mounting shell (4) is fixedly installed on the end of the housing (2) away from the motor (1) parallel to the motor shaft (6). The coupling includes an intermediate shaft (7) and a differential (8). The intermediate shaft (7) is rotatably supported at both ends by ball bearings (74). A transmission gear one (72) and a transmission gear two (73) are placed in the intermediate shaft (7). The transmission gear two (73) meshes with a helical gear (62). The differential (8) includes a frame (81). An external gear ring (82) that meshes with the transmission gear one (72) is fixedly installed on the outside of the frame (81). Two output gears (84) are symmetrically installed on the frame (81) at the rotation axis of the external gear ring (82). The two output gears (84) are connected by bevel gears (83). A damper (9) is provided in the middle section of the output gear (84). The damper (9) can change the rotational resistance of the output gear (84). A wheel axle (3) is rotatably mounted in a mounting housing (4) via a bearing. One end of the wheel axle (3) located inside the housing (2) is provided with a spline head. The wheel axle (3) is engaged with the spline hole (841) of the output gear (84) via the spline head.

2. The electric golf cart rear-wheel drive assembly according to claim 1, characterized in that, The motor shaft (6) includes a drive shaft (61), which is connected to the motor (1) via a coupling. The drive shaft (61) is provided with tapered roller bearings at both ends of the helical gear (62), and the tapered roller bearings are connected to the housing (2).

3. The electric golf cart rear-wheel drive assembly according to claim 2, characterized in that, The intermediate shaft (7) includes a shaft body (71), the thickness of the second transmission gear (73) is twice the thickness of the first transmission gear (72), the first transmission gear (72) and the external gear ring (82) are connected by a straight key, and the first transmission gear (72) is centrally located in the middle of the shaft body (71).

4. The electric golf cart rear-wheel drive assembly according to claim 1, characterized in that, The motor shaft (6) includes a second drive shaft (63) and a coaxial rotating sleeve (64) coaxially mounted. The second drive shaft (63) is assembled and connected to the motor (1) via a coupling. A stabilizer (5) is provided at the end of the second drive shaft (63) away from the motor (1). The stabilizer (5) is located outside the housing (2). The second drive shaft (63) and the coaxial rotating sleeve (64) are assembled and connected to the stabilizer (5) via a first meshing part (631) and a second meshing part (641) respectively. The stabilizer (5) enables damped torsion to occur between the second drive shaft (63) and the coaxial rotating sleeve (64).

5. The electric golf cart rear-wheel drive assembly according to claim 4, characterized in that, The stabilizer (5) includes a fixed shell (51), which is fixedly connected to the shell (2) by bolts. The fixed shell (51) has a coaxially arranged active disk (52) and driven disk (53) inside. A torque assembly (54) is provided between the active disk (52) and the driven disk (53). A counterweight disk (521) is fixedly connected to the end of the active disk (52) away from the driven disk (53).

6. The electric golf cart rear-wheel drive assembly according to any one of claims 1-5, characterized in that, The damper (9) includes a housing (91), a resistance source, and a relay ring (94). The relay ring (94) is coaxially sleeved and fixed on the outer side of the middle section of the output gear (84). The housing (91) is sleeved on the outer side of the relay ring (94). The resistance source applies variable pressure to the friction ring (941) of the relay ring (94) along the axial direction. The housing (91) is provided with a plane bearing (96) on the side of the relay ring (94) away from the resistance source. The outer circumference of the relay ring (94) is provided with a scale groove (942). The housing (91) is provided with a Hall sensor (943) facing the scale groove (942).

7. The electric golf cart rear-wheel drive assembly according to claim 6, characterized in that, The resistance source includes a contact ring (95), and the housing (91) is provided with a movable cavity (93) for the contact ring (95) to slide along the axial direction of the output gear (84). The outer circumferential wall of the contact ring (95) is slidably sealed with the inner wall of the movable cavity (93). A linear sliding sleeve (951) is provided between the contact ring (95) and the housing (91). A straight tube (921) is provided on the side wall of the movable cavity (93) of the housing (91). The straight tube (921) extends to the bottom of the inner side of the housing (2). A pump (92) is connected in series on the straight tube (921).

8. The electric golf cart rear-wheel drive assembly according to claim 6, characterized in that, The resistance source includes an electromagnetic ring (97), the housing (91) is provided with a movable cavity (93) for the electromagnetic ring (97) to slide along the axial direction of the output gear (84), the electromagnetic ring (97) is provided with a lug (971) on its circumferential sidewall, the housing (91) is provided with a straight groove (911) corresponding to the lug (971), and the relay ring (94) is made of a permanent magnet.

9. The electric golf cart rear-wheel drive assembly according to claim 6, characterized in that, The frame (81) adopts a hollow square frame structure. The inner wall of the outer toothed ring (82) is provided with a support block (811). The support block (811) is fixedly connected to the frame (81). The support block (811) has a notch facing the opening of the frame (81).

10. The electric golf cart rear-wheel drive assembly according to claim 9, characterized in that, The lower part of the mounting shell (4) is connected to the cantilever (41) via a rubber pad, and the top of the mounting shell (4) is equipped with a shock absorber (42). The cantilever (41) and the shock absorber (42) are assembled and connected to the vehicle frame.

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