CN-121993594-A - Electric drive system with hydraulic torque converter and forklift

CN121993594ACN 121993594 ACN121993594 ACN 121993594ACN-121993594-A

Abstract

The invention relates to the technical field of electric drive systems, and discloses an electric drive system with a hydraulic torque converter and a forklift. The system comprises a driving motor, a hydraulic torque converter, a speed reducer and a vehicle controller, wherein a locking clutch is integrated in the hydraulic torque converter, an output shaft of the driving motor is connected with an input side of a pump impeller of the hydraulic torque converter, an output side of a turbine of the hydraulic torque converter is connected with an input shaft of the speed reducer, an output end of the speed reducer is used for being connected with a vehicle driving axle, the vehicle controller is configured to control the locking clutch to be connected and disconnected according to the working condition of the vehicle, the locking clutch is controlled to be disconnected when the vehicle is in a low-speed large-torque requirement working condition, the hydraulic torque converter is enabled to work in the torque conversion working condition, and the locking clutch is controlled to be connected when the vehicle is in a high-speed small-torque requirement working condition, so that the pump impeller of the hydraulic torque converter is locked with the turbine machinery, and the vehicle is in the coupling working condition. The vehicle power performance and energy efficiency are improved, the cost of an electric drive system is reduced, and the economy and NVH performance are improved.

Inventors

LONG GUANGCHENG
CHANG FANGPO
QIU JING
LIU BING
HAN BINGBING

Assignees

安徽合力股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260211

Claims (10)

1. The electric drive system with the hydraulic torque converter is characterized by comprising a drive motor (1), the hydraulic torque converter (2), a speed reducer (4) and a vehicle controller, wherein a locking clutch (22) is integrated inside the hydraulic torque converter (2), an output shaft of the drive motor (1) is connected with an input side of a pump wheel (24) of the hydraulic torque converter (2), an output side of a turbine (27) of the hydraulic torque converter (2) is connected with an input shaft of the speed reducer (4), an output end of the speed reducer (4) is used for being connected with a vehicle drive axle, and the vehicle controller is configured to control the engagement and the disengagement of the locking clutch (22) according to vehicle working conditions. When the vehicle is in a low-speed high-torque demand working condition, the locking clutch (22) is controlled to be separated, so that the hydraulic torque converter (2) works in a torque conversion working condition, and when the vehicle is in a high-speed low-torque demand working condition, the locking clutch (22) is controlled to be connected, so that a pump wheel (24) of the hydraulic torque converter (2) is mechanically locked with a turbine (27), and the hydraulic torque converter is in a coupling working condition.
2. The electric drive system with torque converter according to claim 1, characterized in that the lockup clutch (22) is a normally closed clutch.
3. The electric drive system with torque converter according to claim 1 or 2, characterized in that the lockup clutch (22) is controlled by a hydraulic drive mechanism controlled by an electric signal emitted by the vehicle control unit.
4. An electric drive system with torque converter according to claim 1, characterized in that the reduction gear (4) is a multi-stage gear reduction mechanism comprising three pairs of parallel axis gear pairs meshed in sequence, constituting a three-stage reduction.
5. The electric drive system with torque converter according to claim 4, characterized in that the three pairs of parallel axis gear pairs include a first gear pair formed of a first gear (41) and a sixth gear (46), a second gear pair formed of a second gear (42) and a fifth gear (45), and a third gear pair formed of a third gear (43) and a fourth gear (44).
6. The electric drive system with torque converter according to claim 5, characterized in that it further comprises a differential (5) and a pair of drive half shafts (6), the housing of the differential (5) being connected to the final output gear of the reduction gear (4), the two outputs of the differential (5) being connected to the drive half shafts (6) respectively.
7. An electric drive system with a torque converter according to claim 1, characterized in that the drive motor (1), the torque converter (2) and the retarder (4) are integrated in a housing (3).
8. The electric drive system with a torque converter according to claim 7, characterized in that the drive motor (1), the torque converter (2) and the retarder (4) are arranged coaxially in the power transmission direction.
9. A forklift truck, characterized in that it is equipped with an electric drive system with a torque converter according to any one of claims 1 to 8.
10. The forklift of claim 9, wherein said forklift is an electric forklift.

Description

Electric drive system with hydraulic torque converter and forklift Technical Field The invention relates to the technical field of electric drive systems, in particular to an electric drive system with a hydraulic torque converter and a forklift. Background Currently, industrial vehicles such as electric forklifts generally adopt a power system scheme of a driving motor matched with a fixed speed ratio reducer. The scheme has a simple structure, but has obvious defects when facing complex and changeable working conditions. Taking an electric forklift as an example, the working cycle of the electric forklift generally comprises no-load/full-load high-speed running, full-load climbing, low-speed micro-motion loading and unloading and the like, and the load and rotation speed requirements of a driving system are severely changed. A fixed ratio speed reducer cannot optimize both high speed and low speed high torque conditions. In order to meet the maximum speed and maximum grade requirements of the vehicle, the motor is forced to have a wide high-efficiency area and high peak torque and rotational speed capabilities, which results in high costs for the motor and the electronic control system. In actual operation, the motor is often operated in a low-efficiency zone, and particularly, the system is low in overall energy efficiency when the motor climbs a slope at a low speed and a large torque or runs at a high speed. In addition, increasing the size and weight of the motor to meet high torque output, or to meet vehicle speed requirements by increasing rotational speed, can negatively impact noise, vibration and harshness (NVH) performance and economy of the system. Disclosure of Invention The invention aims to solve the problems that a traditional driving motor and a single-speed ratio speed reducer power system in the prior art are difficult to consider the high-efficiency area and high-dynamic output of an electric driving system and the system cost is high, and provides the electric driving system with the hydraulic torque converter and a forklift, so that the dynamic performance and the energy efficiency of a vehicle are improved, the cost of the electric driving system is reduced, and meanwhile, the economy and the NVH performance are improved. In order to achieve the above object, according to one aspect of the present invention, there is provided an electric drive system with a torque converter, the system including a drive motor, a torque converter, a speed reducer, and a vehicle controller, wherein a lockup clutch is integrated in the torque converter, an output shaft of the drive motor is connected to an input side of a pump impeller of the torque converter, an output side of a turbine of the torque converter is connected to an input shaft of the speed reducer, an output end of the speed reducer is used for connecting a vehicle drive axle, and the vehicle controller is configured to control engagement and disengagement of the lockup clutch according to a vehicle condition: When the vehicle is in the working condition of low-speed and high-torque demand, the locking clutch is controlled to be separated, so that the hydraulic torque converter works in the working condition of torque conversion, and when the vehicle is in the working condition of high-speed and low-torque demand, the locking clutch is controlled to be engaged, so that the pump impeller of the hydraulic torque converter is locked with the turbine machinery, and the hydraulic torque converter is in the working condition of a coupling. Preferably, the lockup clutch is a normally closed clutch. Preferably, the lockup clutch is controlled by a hydraulic driving mechanism controlled by an electric signal sent by the vehicle controller. Preferably, the speed reducer is a multi-stage gear speed reducing mechanism, and comprises three pairs of parallel shaft gear pairs which are meshed in sequence to form three-stage speed reduction. Preferably, the three pairs of parallel axis gear pairs include a first gear pair formed of a first gear and a sixth gear, a second gear pair formed of a second gear and a fifth gear, and a third gear pair formed of a third gear and a fourth gear. Preferably, the system further comprises a differential and a pair of drive half shafts, the housing of the differential being connected to the final output gear of the reducer, the two outputs of the differential being connected to the drive half shafts respectively. Preferably, the drive motor, torque converter and retarder are integrated in a housing. Preferably, the drive motor, the torque converter and the speed reducer are arranged coaxially in the power transmission direction. A second aspect of the invention provides a forklift equipped with an electric drive system with a torque converter as described above. Preferably, the forklift is an electric forklift. According to the technical scheme, through the torque amplifying function of the hydraulic torque converter,