CN102943846A - Two-gear automatic transmission for electric automobile - Google Patents

Abstract

The invention discloses a two-speed automatic transmission for an electric vehicle, which comprises two electromagnetic clutches and two fixed-axis gear trains with two-stage deceleration. The working principle of the two sets of fixed-axis gear trains is the same. The power is transmitted to the first pair of gears through the drive motor to complete the first-stage deceleration. By controlling the operation of the electromagnetic clutch, the power is transmitted to the rear pair of gears to complete the second-stage deceleration. In order to realize the switching of the two gears, different combinations of whether the two electromagnetic clutches work or not are controlled. The invention adopts two single electromagnetic clutches as the shifting elements of the two-speed automatic transmission, and has small shifting impact, simple form, compact structure, small volume and light weight, and conforms to the principles of high efficiency and light weight of automobiles.

Description

A two-speed automatic transmission for electric vehicles

Technical field:

The invention relates to a two-speed automatic transmission for an electric vehicle.

Background technique:

Petroleum resource crisis and vehicle exhaust emissions have become two major technical problems faced by vehicles powered by internal combustion engines. The automotive industry must seek vehicles with low emissions and comprehensive utilization of energy. Therefore, the electric vehicle with these characteristics has become a research hotspot in various countries. It is an important way to solve the energy crisis and environmental pollution, and it is an important new type of green transportation in the 21st century.

At present, electric vehicles on the market do not have automatic transmissions, but use single-stage reducers, which mainly rely on controlling the speed of the drive motor itself to achieve speed change. This makes it impossible for the drive motor to provide high instantaneous torque in the constant torque area and high operating speed in the constant power area at the same time. This has led to problems such as low working efficiency of the electric vehicle drive motor and short driving range of the vehicle.

The existing two-speed transmissions for electric vehicles mainly include: the AMT structure and the DCT structure derived from the "deformation" of the automatic transmission of fuel vehicles. When the AMT structure is adopted, a synchronizer is required, and the shifting impact is relatively large at this time; while when the DCT structure is adopted, a dual clutch is required, and the production cost is relatively high at this time.

Therefore it is very necessary to invent a kind of mechanical transmission device suitable for the needs of the electric vehicle according to the characteristics of the drive motor and the characteristics of the electric vehicle itself.

Invention content:

In order to overcome the defects of the prior art, the purpose of the present invention is to provide a two-speed automatic transmission for electric vehicles, which adopts a relatively mature single clutch in domestic technology as the shift element, and compared with the AMT structure, the shift impact is smaller; Compared with the DCT structure, the production cost is lower.

The present invention solves technical problem and adopts following technical scheme:

A two-speed automatic transmission for an electric vehicle:

The two-speed automatic transmission is composed of a first transmission system and a second transmission system connected in parallel, and the first transmission system and the second transmission system do not work at the same time; that is to say, when the first transmission system works, the second transmission system Not working, when the second transmission system is working, the first transmission system is not working.

The first transmission system is a fixed-axis gear transmission system, and the overall structure is a layout of three parallel shafts, which are: a motor, a motor shaft, an upper shaft, and an output shaft; gear, the second gear meshing with the first gear is fixedly connected to the upper shaft through a key, and the coil part of the first electromagnetic clutch is fixedly connected with the coil part of the first electromagnetic clutch on the upper shaft through a key, and the first electromagnetic clutch The armature part of the clutch is fixedly connected with the third gear through a screw, the third gear is supported on the upper shaft through a bearing, and meshes with the fourth gear fixedly connected with the output shaft through a key;

The second transmission system is a fixed-axis gear transmission system, and the overall structure is a layout of three parallel shafts, which are: the motor, the motor shaft, the lower shaft, and the output shaft; gear, the fifth gear meshed with the first gear is fixedly connected to the lower shaft through a key, and the coil part of the second electromagnetic clutch is fixedly connected with the coil part of the second electromagnetic clutch on the lower shaft through a key, and the second electromagnetic clutch The armature part of the clutch is fixedly connected with the sixth gear through a screw, and the sixth gear is supported on the lower shaft through a bearing, and meshes with the seventh gear fixedly connected with the output shaft through a key; two transmission systems Power and torque are output by the output shaft.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. The present invention uses a single clutch as a shifting element, and compared with the AMT structure, the shifting impact is smaller; compared with the DCT structure, the production cost is lower. Therefore, its comprehensive performance is good, and it is easy to realize industrialization development.

2. The arrangement of transmission gears is simple, compact in structure, small in size and light in weight, which conforms to the principle of lightweight vehicles.

Description of drawings:

Fig. 1 is a structural schematic diagram of the present invention.

Labels in the figure: 1 motor, 2 first gear, 3 second gear, 4 third gear, 5 fourth gear, 6 fifth gear, 7 sixth gear, 8 seventh gear, I is the motor shaft, II is the upper shaft, III is the lower shaft, IV is the output shaft, C1 is the first electromagnetic clutch, and C2 is the second electromagnetic clutch.

The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

Detailed ways:

Embodiment: In conjunction with Fig. 1, the two-speed automatic transmission for electric vehicles of the present embodiment is composed of the first transmission system and the second transmission system in parallel, and the first transmission system and the second transmission system do not work at the same time; that is to say when When the first transmission system works, the second transmission system does not work, and when the second transmission system works, the first transmission system does not work.

The first transmission system is a fixed-axis gear transmission system, and the overall structure is a layout of three parallel shafts, which are: motor 1 and motor shaft I (the input shaft of the first transmission system, which is also the wheel shaft of the first gear), and the upper shaft II , output shaft IV; on the motor shaft I, the first gear 2 is fixedly connected by a key, and the second gear 3 meshing with the first gear 2 is fixedly connected on the upper shaft II by a key, and is connected by a key on the upper shaft II). The coil part of the first electromagnetic clutch C1 is fixedly connected, and the armature part of the first electromagnetic clutch C1 is fixedly connected with the third gear 4 through a screw, and the third gear 4 is supported on the upper shaft II through a bearing, and is fixedly connected with the through key The fourth gear (5) on output shaft IV meshes.

The second transmission system is a fixed-axis gear transmission system, and the overall structure is the layout of three parallel shafts, which are: motor 1, motor shaft I, lower shaft III, and output shaft IV; A gear 2, the fifth gear 6 meshed with the first gear 2 is fixedly connected on the lower shaft III by a key, and is fixedly connected with the coil part of the second electromagnetic clutch C2 on the lower shaft III by a key, the second electromagnetic clutch C2 The armature part is fixedly connected with the sixth gear 7 through screws, and the sixth gear 7 is supported on the lower shaft III through a bearing, and meshes with the seventh gear 8 fixedly connected on the output shaft IV through a key; both transmission systems are Power and torque are output from the output shaft IV.

During work, the motor 1 drives the motor shaft I (the axle of the first gear 2) to rotate clockwise at a certain speed and torque. When the second electromagnetic clutch C2 is engaged and the first electromagnetic clutch C1 is not working, the power is driven by the drive motor The ground gear 2 and the fifth gear 6 complete the first-stage deceleration, and then pass the sixth gear 7 and the seventh gear 8 to complete the second-stage deceleration, and finally the power is output through the output IV. At this time, the transmission is in the D1 gear position; when the first electromagnetic clutch When C1 is engaged and the second electromagnetic clutch C2 is not working, the power is driven by the drive motor through the first gear 2 and the second gear 3 to complete the first-stage deceleration, and then through the third gear 4 and the fourth gear 5 to complete the second-stage deceleration. Finally, the power is output through the output shaft IV. At this time, the transmission is in the D2 gear position; when the input motor drives the motor shaft I to rotate counterclockwise with a certain speed and torque, the second electromagnetic clutch C2 is engaged, and the first electromagnetic clutch C1 is not working. When the power is driven by the drive motor through the first gear 2 and the fifth gear 6 to complete the first-stage deceleration, then through the sixth gear 7 and the seventh gear 8 to complete the second-stage deceleration, and finally the power is output through the output shaft IV. At this time, the transmission is in the R gear Location.

Thus, two forward gears and one reverse gear can be realized by controlling different combinations of two single electromagnetic clutches in the control system.

Taking the actual development of a certain type of pure electric vehicle as an example, the number of selected gears is two, the transmission ratio of the first gear is 11.74, and the transmission ratio of the second gear is 4.83. The number of teeth of each gear is calculated by matching the gear teeth, as shown in Table 1.

Table 1 Gear teeth table

As shown in Figure 1, the two-speed automatic transmission uses two shift actuators: two electromagnetic clutches.

The actuators of each gear are shown in Table 2.

Table 2 Shift actuator worksheet

Note: "●" in the table means combination, "○" means separation;

The description of the power transmission route of each gear is combined with Figure 1 and Table 2.

1. Neutral position - N position

When the position is N, neither the first electromagnetic clutch C1 nor the second electromagnetic clutch C2 works, and the motor cannot transmit power to the output shaft IV at this time, and the vehicle runs by inertia or stops.

2. Forward gear - D position (the motor rotates clockwise)

(1) One gear forward (D1 gear)

In the D1 gear, the second electromagnetic clutch C2 works, and the first electromagnetic clutch C1 does not work.

The power drives the first gear 2 to rotate clockwise through the motor shaft, and the first gear 2 drives the fifth gear 6 to rotate counterclockwise to complete a first-stage deceleration. Due to the operation of the second electromagnetic clutch C2, the sixth gear 7 and the lower shaft III pass through The second electromagnetic clutch C2 is fixedly connected, and the power is transmitted from the fifth gear 6 to the lower shaft III, then to the second electromagnetic clutch C2, and then to the sixth gear 7 to make it rotate counterclockwise, and the sixth gear 7 drives the seventh The gear 8 rotates clockwise to complete the two-stage reduction, and finally the output shaft IV rotates clockwise to output power. This gear is a medium and low gear, mainly used for medium and low speed driving and climbing.

(2) Forward second gear (D2 gear)

In the D2 gear, the first electromagnetic clutch C1 works, and the second electromagnetic clutch C2 does not work.

The power drives the first gear 2 to rotate clockwise through the motor shaft, and the first gear 2 drives the second gear 3 to rotate counterclockwise to complete a first-stage deceleration. Due to the operation of the first electromagnetic clutch C1, the third gear 4 and the upper shaft II pass through The first electromagnetic clutch C1 is fixedly connected, and the power is transmitted from the second gear 3 to the upper shaft II, then to the first electromagnetic clutch C1, and then to the third gear 4 to make it rotate counterclockwise, and the third gear 4 drives the fourth gear 5 rotates clockwise to complete the two-stage deceleration, and finally the output shaft IV rotates clockwise to output power. This gear is a high-speed gear, mainly used for high-speed driving.

3. Reverse gear - R position (the motor rotates counterclockwise)

In the R gear, the second electromagnetic clutch C2 works, and the first electromagnetic clutch C1 does not work.

The power transmission route is the same as that of the D1 gear. Since the motor rotates counterclockwise, the final output shaft IV rotates counterclockwise to output power.

Claims (1)

1. A two-speed automatic transmission for electric vehicles, characterized in that: The two-speed automatic transmission is composed of a first transmission system and a second transmission system connected in parallel, and the first transmission system and the second transmission system do not work at the same time; The first transmission system is a fixed-axis gear transmission system, and the overall structure is a layout of three parallel shafts, which are: motor (1), motor shaft (I), upper shaft (II), and output shaft (IV); The first gear (2) is fixedly connected to the motor shaft (I) through a key, and the second gear (3) meshing with the first gear (2) is fixedly connected to the upper shaft (II) through a key , and the coil part of the first electromagnetic clutch (C1) is fixed on the upper shaft (II) through a key, and the armature part of the first electromagnetic clutch (C1) is fixed with the third gear (4) through screws connected, the third gear (4) is supported on the upper shaft (II) through a bearing, and meshes with the fourth gear (5) fixedly connected to the output shaft (IV) through a key; The second transmission system is a fixed-axis gear transmission system, and the overall structure is a layout of three parallel shafts, which are: motor (1), motor shaft (I), lower shaft (III), and output shaft (IV); The first gear (2) is fixedly connected to the motor shaft (I) through a key, and the fifth gear (6) meshing with the first gear (2) is fixedly connected to the lower shaft (III) through a key , and the coil part of the second electromagnetic clutch (C2) is fixed on the lower shaft (III) through a key, and the armature part of the second electromagnetic clutch (C2) is fixed with the sixth gear (7) through screws Connected, the sixth gear (7) is supported on the lower shaft (III) through a bearing, and meshes with the seventh gear (8) fixedly connected to the output shaft (IV) through a key; two transmissions The system outputs power and torque through the output shaft (IV).

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