Powertrain

Abstract

The invention discloses a power transmission system, including a motor and a gearbox, the gearbox including a housing and a transmission mechanism and a brake arranged in the housing; the transmission mechanism includes an input mandrel, a mandrel hub, a hollow shaft hub, a hollow shaft, and a transmission output assembly, the transmission output assembly includes a plurality of transmission output paths, the hollow shaft is coaxially assembled outside the mandrel and can rotate freely relative to the mandrel, the inner end of the mandrel hub is fixed to the outside of the input mandrel, and the outer end is connected to the hollow shaft hub through a clutch, the inner end of the hollow shaft hub is fixed to the hollow shaft, and the transmission output assembly is arranged outside the hollow shaft; the transmission mechanism is coaxially connected to the output shaft of the motor through the housing with its mandrel, and the brake is arranged outside the transmission output assembly to control the transmission or locking of each transmission output path of the transmission output assembly. Multi-speed shifting is realized; through transmission speed shifting, the torque and speed working width of the drive motor can be effectively expanded, so that the motor works in a high-efficiency range, thereby improving the efficiency of the power system.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicle power transmission, and in particular relates to a power transmission system. Background Art

[0002] The planetary gear structure has actually been used in the automotive field for a long time. Most automatic transmissions on the market use several sets of planetary gears, and then cooperate with torque converters to achieve the function of speed change. The three mechanisms of the planetary gear, the sun gear, the ring gear, and the planetary carrier, can be connected to three power output or input ends respectively. If any one of them is fixed, the other two are equivalent to ordinary gear meshing; if two of them are fixed, the entire planetary gear is locked. The planetary gear is not connected to any input and output mechanism, and it is always free to rotate, otherwise the entire planetary gear set cannot rotate. The planetary carrier is connected to the power. After the planetary carrier is fixed, the planetary gear only rotates on its own, but does not revolve around the sun gear. However, the power transmission system using planetary gear technology currently has the following defects: First, when the motor drives the vehicle alone, there is only one deceleration path, and the final transmission of this deceleration path is relatively high, so that when the driving speed is low, the motor also needs to run at a low-efficiency higher speed. Secondly, when the engine speed is suitable for driving the wheels alone, but the required torque is too high or too low, there is no way to adjust the engine output torque through the motor, and the engine cannot work in the optimal range at this time. If the motor is to work, the engine speed can only be changed at the same time, and the engine efficiency will also decrease. Summary of the invention

[0003] The purpose of the present invention is to address the deficiencies of the prior art and provide an improved power transmission system capable of efficiently outputting multi-speed power.

[0004] The power transmission system provided by the present invention includes a motor and a gearbox, wherein the gearbox includes a housing and a transmission mechanism and a brake arranged in the housing; the transmission mechanism includes an input core shaft, a core shaft hub, a hollow shaft hub, a hollow shaft, and a transmission output assembly, wherein the transmission output assembly includes a plurality of transmission output paths, the hollow shaft is coaxially assembled outside the core shaft and can rotate freely relative to the core shaft, the inner end of the core shaft hub is fixedly connected to the outside of the input core shaft, and the outer end is connected to the hollow shaft hub through a clutch, the inner end of the hollow shaft hub is fixedly connected to the hollow shaft, and the transmission output assembly is arranged outside the hollow shaft; the transmission mechanism has its core shaft passing through the housing and is coaxially connected to the output shaft of the motor, and the brake is arranged outside the transmission output assembly to control the transmission or locking of each transmission output path of the transmission output assembly.

[0005] In a specific embodiment, the transmission output assembly includes a pair of planetary gear sets axially arranged outside the hollow shaft, with the front row being the side close to the motor; the front row planetary carrier is assembled on the outside of the hollow shaft through a shaft sleeve and can rotate freely around the hollow shaft, and the rear row sun gear is fixed to the outside of the hollow shaft and can rotate with the hollow shaft; the front row ring gear is connected to the rear row planetary carrier as an output component, and the front row planetary carrier is connected to the rear row ring gear; brakes are provided on the outside of the front row sun gear and the rear row ring gear.

[0006] In order to achieve multi-speed output, the hollow shaft hub includes a front input hub and a rear input hub; the inner ring of the front input hub is fixedly connected to the front planetary carrier, and the outer ring is connected to the outer side of the core shaft hub through a clutch; the inner ring of the rear input hub is threadedly connected to the hollow shaft, and the outer ring is connected to the inner side of the core shaft hub through a clutch.

[0007] Preferably, the input core shaft is a stepped shaft, including a large diameter section and a small diameter section; the outer diameter of the hollow shaft matches the outer diameter of the large diameter section, and the inner diameter matches the outer diameter of the small diameter section; the length of the small diameter section is greater than the length of the hollow shaft, and the hollow shaft is assembled outside the small diameter section of the input core shaft through a sleeve.

[0008] Furthermore, the front row planetary carrier and the rear row planetary carrier have the same structure, both including a shaft sleeve section and a flange plate, and the flange plate is provided with a shaft hole; the front row planetary carrier is assembled on the outside of the hollow shaft with its shaft sleeve section; the rear row planetary carrier is assembled on the small diameter section of the core shaft extending to the outside of the hollow shaft with its shaft sleeve section.

[0009] Correspondingly, the front gear ring includes a gear ring body and a connecting plate, an axial hole is provided on the connecting plate, one end of the gear ring body is meshed with the front row planetary gear, and the other end is connected to the connecting plate, and the connecting plate is connected to the rear row planetary carrier via a connecting shaft placed in the axial hole.

[0010] Correspondingly, the rear gear ring includes a gear ring body and a connecting plate, an axial hole is provided on the connecting plate, one end of the gear ring body is meshed with the rear planetary gear, and the other end is connected to the connecting plate, and the connecting plate is connected to the front planetary carrier via a connecting shaft placed in the axial hole.

[0011] Preferably, the clutch and the brake are both multi-plate clutches.

[0012] In order to improve the heat dissipation effect, in a specific embodiment, the motor includes a shell, a stator, a rotor and a main shaft; the main shaft includes a solid section and a hollow section, and an oil outlet hole is arranged on the side wall of the hollow section; a heat dissipation oil channel connected to the oil hole is arranged in the rotor; a spiral heat dissipation oil channel is arranged in the shell; a radial hole is arranged on the input core shaft, and a gear oil pump is arranged outside the radial hole, and the gear oil pump injects oil into the heat dissipation oil channel and the spiral heat dissipation oil channel.

[0013] Furthermore, a positioning groove is physically provided on the outer end of the housing for installing the piston of the clutch.

[0014] The present invention can select different transmission output paths through the cooperation of brakes and clutches to achieve torque requirements under different vehicle speed conditions and realize multi-speed shifting; the transmission speed shifting can effectively expand the torque and speed working width of the drive motor and improve the adaptability under different working conditions; at the same time, due to the use of corresponding speed transmission under different working conditions, the motor can work in a better high-efficiency range, thereby improving the efficiency of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional schematic diagram of a preferred embodiment of the present invention.

[0016] Figure 2 for Figure 1 Enlarged diagram of the gearbox.

[0017] Figure 3 for Figure 1 An enlarged schematic diagram of the transmission output assembly.

[0018] Figure 4 for Figure 1 Enlarged schematic diagram of the motor.

[0019] Figure 5 This is an equivalent schematic diagram of the transmission path of this preferred embodiment.

[0020] Fig. 6A , 6B , 6C, and 6D are equivalent schematic diagrams of the transmission path of this preferred embodiment when it is in the first gear, second gear, third gear, and fourth gear respectively.

[0021] Figure serial number:

[0022] 1—Gearbox,

[0023] 11 - box shell,

[0024] 121 - input mandrel, 122 - hollow shaft, 123 - mandrel hub, 124 - front input hub, 125 - rear input hub, 126 - connecting shaft, 127 - pin shaft,

[0025] 13—Gear oil pump;

[0026] 2—Motor,

[0027] 21 - housing, 22 - stator, 23 - rotor, 24 - main shaft;

[0028] CL1—first multi-plate clutch, CL2—second multi-plate clutch;

[0029] B1—first brake, B2—second brake;

[0030] R1—front ring gear, C1—front planetary carrier, S1—front sun gear;

[0031] R2—front and rear ring gears, C2—rear planetary carrier, S2—rear sun gear. DETAILED DESCRIPTION

[0032] like Figure 1 As shown, the power transmission system disclosed in this embodiment includes a gearbox 1 and a motor 2; the gearbox 1 includes a housing 11, a transmission mechanism and a brake, wherein the transmission mechanism inputs a spindle 121, a hollow shaft 122, a spindle hub 123, a hollow shaft hub, and a transmission output assembly.

[0033] like Figure 2 As shown, the input core shaft 121 is a stepped shaft, including a large diameter section and a small diameter section; the outer diameter of the hollow shaft 124 matches the outer diameter of the large diameter section, and the inner diameter matches the outer diameter of the small diameter section; a radial hole is provided on the entity of the large diameter section, and a gear oil pump 13 is provided outside the radial hole; the length of the small diameter section is greater than the length of the hollow shaft, and the hollow shaft is assembled on the outside of the small diameter section of the input core shaft through a shaft sleeve; the inner end of the core shaft hub 123 is fixedly connected to the outside of the large diameter section of the input core shaft.

[0034] There are two hollow hubs, namely the front input hub 124 and the rear input hub 125. The inner ring of the front input hub is fixedly connected to the front planet carrier C1, the outer ring is connected to the driven plate CL2 of the second multi-plate clutch, and the driving plate of the multi-plate clutch CL2 is connected to the outer side of the mandrel hub. The inner ring of the rear input hub 125 is threadedly connected to the hollow shaft 124, and the outer ring is connected to the inner side of the mandrel hub through the first multi-plate clutch CL1.

[0035] like Figure 3 As shown, the transmission output assembly includes a pair of planetary gear sets arranged axially outside the hollow shaft, the front planetary gear set is near the motor side, and the rear planetary gear set is near the other side. The front planetary gear set includes the front ring gear R1, the front planet carrier C1 and the front sun gear S1, and the rear planetary gear set includes the rear ring gear R2, the rear planet carrier C2 and the rear sun gear S2. The front planet carrier is assembled outside the hollow shaft through the shaft sleeve and can rotate freely around the hollow shaft, and the rear sun gear is fixed outside the hollow shaft and can rotate with the hollow shaft; the front ring gear is connected to the rear planet carrier, and the front planet carrier is connected to the rear ring gear; the front sun gear and the rear ring gear are both provided with multi-plate clutches as brakes, the first brake outside the front sun gear is marked as B1; the second brake outside the rear ring gear is marked as B2.

[0036] The front row planetary carrier and the rear row planetary carrier have the same structure, both including a shaft sleeve section and a flange plate, and the flange plate is provided with a shaft hole; the front row planetary carrier is assembled on the outside of the hollow shaft with its shaft sleeve section; the rear row planetary carrier is assembled on the small diameter section of the core shaft extending outside the hollow shaft with its shaft sleeve section. The front row ring gear includes a ring gear body and a connecting plate, and a shaft hole is provided on the connecting plate. One end of the ring gear body meshes with the front row planetary gear and the other end is connected to the connecting plate. The connecting plate is connected to the rear row planetary carrier through a connecting shaft 126 placed in the shaft hole. The rear row ring gear includes a ring gear body and a connecting plate, and a shaft hole is provided on the connecting plate. One end of the ring gear body meshes with the rear row planetary gear and the other end is connected to the connecting plate. The connecting plate is connected to the front row planetary carrier through a pin shaft 127 placed in the shaft hole.

[0037] like Figure 4 As shown, the motor 2 includes a housing 21, a stator 22, a rotor 23 and a main shaft 24; the main shaft includes a solid section and a hollow section, and an oil outlet is provided on the side wall of the hollow section; a heat dissipation oil channel connected to the oil hole is provided in the rotor; a spiral heat dissipation oil channel is provided in the housing; oil is injected into the heat dissipation oil channel and the spiral heat dissipation oil channel through the gear oil pump on the input mandrel. Thus, the heat generated by the motor when working is effectively taken away, and the cooling and heat dissipation capacity of the motor is improved; so that the gear oil pump can provide hydraulic pressure for the hydraulic pressure source of the gear shifting clutch operation of the gear shifting operation, and can also provide power for the cooling and lubrication inside the motor and the gearbox.

[0038] like Figure 5 Therefore, in this embodiment, the front ring gear R1 and the rear planetary carrier C2 are connected as a component as an output component, referred to as R1-C2; the front planetary carrier C1 and the rear ring gear R2 are connected as a component, referred to as C1-R2; the front sun gear S1 is connected to the brake B1, the rear sun gear S2 is controlled by the clutch CL1, the C1-R2 component is controlled by the clutch CL2, and is connected to the brake B2, and the R1-C2 component is used as an output component. According to the lever analysis method of planetary gears, the equivalent lever transmission status table of the above multi-speed transmission is as follows:

[0039]

[0040] That is, when it is put into use, the following four output gears can be selected according to the working conditions.

[0041] First gear: Fig. 6A As shown, the CL1 clutch is engaged, the motor power is transmitted to the rear sun gear S2 through CL1, and the B2 brake is engaged, so that the rear ring gear R2-C1 component is fixed, and the motor power is output through the rear planetary carrier C2. The front planetary gears are in a free rotation state and do not transmit power. In this state, the gearbox reduces speed and the speed ratio is: k2+1, where k2 is the proportional coefficient of the rear planetary gear, specifically the ratio of the number of teeth of the rear planetary gear ring to the number of teeth of the rear planetary gear sun gear.

[0042] Second gear: Figure 6B As shown, when the first gear enters the second gear working state, the motor power still transmits the input power to the rear sun gear S2 through the CL1 clutch, the B2 brake is released, the front sun gear S1 brake B1 is engaged, the rear ring gear R2-C1 is converted from a static fixed state to a transmission state, and the front sun gear S1 is converted from the brake B1 to a braking state, and the input power is transmitted to the output through the C2-R1 component. In this state, the gearbox outputs the reduction gear, and the speed ratio is (k1+k2+1) / (k1+1); wherein k1 is the proportional coefficient of the front planetary row, specifically the ratio of the number of teeth of the front planetary row ring gear R1 to the number of teeth of the front planetary row sun gear S1; k2 is the proportional coefficient of the rear planetary row, specifically the ratio of the number of teeth of the rear planetary row ring gear to the number of teeth of the rear planetary row sun gear.

[0043] Third gear: Figure 6C As shown, when the second gear is switched to the third gear, the brake B1 fixing the front sun gear S1 is released, the clutch CL2 at the input end is engaged, and the motor input power is transmitted to the rear sun gear S2 via the CL1 clutch, and at the same time, the CL2 clutch is transmitted to the C1-R2 component, and then transmitted to the R1-C2 component via the planetary gear set to output power. In this state, the gearbox directly outputs the gear, and the speed ratio is 1;

[0044] Fourth gear: Fig.6D As shown, when the third gear enters the fourth gear, the input end clutch CL1 is released, and the input power is transmitted to the C1-R2 component through the CL2 clutch, and the brake B1 connected to the front sun gear S1 is engaged, S1 is fixed, and the power is output through the R1-C2 component. In this state, the transmission outputs in overdrive, and the speed ratio is: k1 / (k1+1); wherein k1 is the proportional coefficient of the front planetary gear, specifically the ratio of the number of teeth of the front planetary gear ring R1 to the number of teeth of the front planetary gear sun gear S1.

[0045] Moreover, in actual use, the present embodiment sets the clutch CL1 and the brake B1 to be normally engaged, so that when the system starts working, the first gear output can be achieved without the need for the hydraulic pump to provide pressure; when the system is running, the internal hydraulic oil pump or the external electronic oil pump can provide pressure to achieve the switching of the clutch working state, thereby achieving gear shifting.

[0046] In actual application, this solution is based on different vehicle requirements. For example, if a two-speed ratio or three-speed ratio transmission scheme is required, it is only necessary to reduce the number of clutches.

[0047] Equivalent to the prior art, the present invention has the following beneficial technical effects:

[0048] (1) Two planetary gear sets are used to form a transmission output assembly, wherein the front planetary carrier is connected to the rear ring gear to form a first component, and the rear planetary carrier is connected to the front ring gear to form a second component, and the second component serves as an output component. The first component is connected to two clutches, wherein the rear sun gear is connected to the input shaft through a clutch, and the front sun gear is connected to the gearbox housing through a clutch, thereby realizing four gear shifting.

[0049] (2) An oil pump integrated inside the gearbox is used to provide hydraulic pressure for the hydraulic pressure source of the gear shifting clutch operation, and also provides lubrication for the cooling and lubrication of the motor and the gearbox. The motor of the power source adopts an oil cooling design, and its oil cooling circuit design includes a spiral heat dissipation oil channel of the housing and a cooling and heat dissipation oil channel inside the motor stator and rotor, thereby effectively removing the heat generated by the motor when it is working and improving the motor's cooling and heat dissipation capacity. In addition to the mechanical oil pump, an electronic oil pump is integrated inside the multi-speed transmission to supplement the hydraulic pressure of the multi-speed transmission shifting operation, and also provide a hydraulic pressure power source for the vehicle's power steering.

[0050] (3) In view of the fact that the motor can work stably from zero speed, the clutch and brake are designed to be always connected. When the system starts working, the first gear output can be achieved without the need for a hydraulic pump to provide pressure. When the system is running, pressure can be provided by an internal hydraulic oil pump or an external electronic oil pump to switch the clutch working state, thereby achieving gear shifting.

Claims

1. A power transmission system, comprising a motor and a gearbox, characterized in that: The gearbox comprises a housing and a transmission mechanism and a brake arranged in the housing; The transmission mechanism includes an input mandrel, a mandrel hub, a hollow shaft hub, a hollow shaft, and a transmission output assembly. The transmission output assembly includes multiple transmission output paths. The hollow shaft is coaxially assembled outside the input mandrel and can rotate freely relative to the input mandrel. The inner end of the mandrel hub is fixed to the outside of the input mandrel, and the outer end is connected to the hollow shaft hub through a clutch. The transmission output assembly is arranged outside the hollow shaft. The transmission mechanism has its input spindle passing through the housing and coaxially connected to the output shaft of the motor, and the brake is arranged outside the transmission output assembly to control the transmission or locking of each transmission output path of the transmission output assembly; The transmission output assembly includes a pair of planetary gear sets arranged axially outside the hollow shaft, with the motor side being the front row; the front row planetary carrier is assembled outside the hollow shaft through a shaft sleeve and can rotate freely around the hollow shaft, and the rear row sun gear is fixed outside the hollow shaft and can rotate together with the hollow shaft; the front row ring gear is connected to the rear row planetary carrier as an output member, and the front row planetary carrier is connected to the rear row ring gear; brakes are provided outside the front row sun gear and the rear row ring gear; The hollow shaft hub comprises a front input hub and a rear input hub; the inner ring of the front input hub is fixedly connected to the front planet carrier, and the outer ring is connected to the outer side of the core shaft hub through a clutch; the inner ring of the rear input hub is threadedly connected to the hollow shaft, and the outer ring is connected to the inner side of the core shaft hub through a clutch; The clutch and the brake are both multi-plate clutches.

2. The power transmission system according to claim 1, characterized in that: The input core shaft is a stepped shaft, including a large diameter section and a small diameter section; the outer diameter of the hollow shaft matches the outer diameter of the large diameter section, and the inner diameter matches the outer diameter of the small diameter section; the length of the small diameter section is greater than the length of the hollow shaft, and the hollow shaft is assembled outside the small diameter section of the input core shaft through a sleeve.

3. The power transmission system according to claim 2, characterized in that: The front planetary carrier and the rear planetary carrier have the same structure, both including a shaft sleeve section and a flange plate, and the flange plate is provided with a shaft hole; the front planetary carrier is assembled on the outside of the hollow shaft with its shaft sleeve section; the rear planetary carrier is assembled on the small diameter section of the input core shaft extending outside the hollow shaft with its shaft sleeve section.

4. The power transmission system according to claim 3, characterized in that: The front ring gear includes a ring gear body and a connecting plate, an axial hole is arranged on the connecting plate, one end of the ring gear body is meshed with the front row planetary gear, and the other end is connected to the connecting plate, and the connecting plate is connected to the rear row planetary carrier via a connecting shaft placed in the axial hole.

5. The power transmission system according to claim 3, characterized in that: The rear gear ring includes a gear ring body and a connecting plate. The connecting plate is provided with an axial hole. One end of the gear ring body is meshed with the rear planetary gear and the other end is connected to the connecting plate. The connecting plate is connected to the front planetary carrier via a connecting shaft placed in the axial hole.

6. The power transmission system according to any one of claims 1 to 5, characterized in that: The motor comprises a casing, a stator, a rotor and a main shaft; the main shaft comprises a solid section and a hollow section, and an oil outlet hole is arranged on the side wall of the hollow section; a heat dissipation oil channel connected to the oil hole is arranged in the rotor; a spiral heat dissipation oil channel is arranged in the casing; a radial hole is arranged on the input core shaft, and a gear oil pump is arranged outside the radial hole, and the gear oil pump injects oil into the heat dissipation oil channel and the spiral heat dissipation oil channel.

7. The power transmission system according to claim 6, characterized in that: A positioning groove is physically provided on the outer end of the housing for installing the piston of the clutch.

Images