An eight-speed automatic transmission with smooth transmission

Abstract

The invention provides an eight-speed automatic transmission with smooth transmission. It includes a transmission housing, an input shaft, an output shaft, an 11-rod 2-degree-of-freedom separable planetary gear system and a torque transmission device installed inside the transmission housing. The 11-rod 2-degree-of-freedom separable planetary gear system includes four basic planetary gear system units arranged in sequence from the input shaft to the output shaft; the clutch in the torque transmission device connects the input shaft and the planetary gear system, the brake in the torque transmission device connects the transmission housing and the planetary gear system, and three combinations of each clutch and each brake are selectively engaged to establish eight forward gear ratios and one reverse gear ratio between the input shaft and the output shaft, which are 5, 3, 2, 1.4, 1, 0.82, 0.71, 0.6, and 4 respectively. The structure is simple, the step ratio between gears is stable, the gear shifting is smooth, the transmission efficiency is high, the control is simple, and it is conducive to reducing the size, weight and manufacturing cost of the automatic transmission.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle transmission, and in particular relates to an eight-speed automatic transmission with smooth transmission. Background Art

[0002] The automatic transmission is one of the core devices of the automobile and the focus of competition among countries around the world. The mechanism is the carrier for the automatic transmission to realize the motion function. The design and invention of a new mechanism is the source and foundation for the development of a new automatic transmission. The 8-speed automatic transmission mechanism is mainly composed of a planetary gear train, a clutch and a brake. In the prior art, the transmission has good adaptability to the driving road conditions and can shift gears according to different resistances, so that the power output of the power unit can be matched with the driving road conditions to a certain extent, and therefore is widely used. The existing transmission is usually provided with multiple sets of constantly meshed gear pairs, the number of gear pairs is the same as the number of gear positions of the transmission, and the gears are shifted by different control combinations of the clutch and the brake. When the number of gear positions of the transmission is large, the structural complexity and processing difficulty of the transmission will be greatly increased. At the same time, the volume of the transmission is also greatly increased, making it difficult to be mounted on some small vehicles with high cost requirements. Patent CN103758977B discloses an 8-speed automatic transmission. In the mechanism displayed, they arranged 7 control elements, which will increase the volume of the entire automatic transmission. And the step between the 1st gear and the 2nd gear displayed is relatively large, and the shifting shock is relatively large. The step ratio between transmission gears is reasonable, so gear shifting will be smoother and fuel consumption will be relatively reduced. Summary of the invention

[0003] The purpose of the present invention is to provide an eight-speed automatic transmission with smooth transmission in view of the above-mentioned deficiencies in the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention provides an eight-speed automatic transmission with smooth transmission, comprising a transmission housing; an input shaft, an output shaft and a torque transmission device installed inside the transmission housing, and an 11-rod 2-DOF separable planetary gear train, wherein the 11-rod 2-DOF separable planetary gear train comprises four basic planetary gear train units arranged in sequence from the input shaft to the output shaft, namely a first basic planetary gear train unit, a second basic planetary gear train unit, a third basic planetary gear train unit and a fourth basic planetary gear train unit, each of which comprises a ring gear, a planetary gear, a planet carrier and a sun gear; the first basic planetary gear train unit comprises a first gear ring ... The planet carrier of the planetary gear train unit is fixedly connected to the planet carrier of the second basic planetary gear train unit; the ring gear of the first basic planetary gear train unit is fixedly connected to the sun gear of the second basic planetary gear train unit; the ring gear of the second basic planetary gear train unit is fixedly connected to the sun gear of the third basic planetary gear train unit; the planet carrier of the third basic planetary gear train unit is fixedly connected to the ring gear of the fourth basic planetary gear train unit; the ring gear of the third basic planetary gear train unit is fixedly connected to the planet carrier of the fourth basic planetary gear train unit, and the ring gear of the third basic planetary gear train unit and the planet carrier of the fourth basic planetary gear train unit are both fixedly connected to the output shaft;

[0006] The torque transmission device comprises:

[0007] a first clutch, which connects the input shaft to the ring gear of the first basic planetary gear train unit and the sun gear of the second basic planetary gear train unit respectively;

[0008] a second clutch connecting the input shaft to the planet carrier of the first basic planetary gear train unit and the planet carrier of the second basic planetary gear train unit;

[0009] a third clutch connecting the input shaft to the planet carrier of the third basic planetary gear train unit and the ring gear of the fourth basic planetary gear train unit;

[0010] a first brake connected to the sun gear of the first basic planetary gear train unit;

[0011] a second brake connecting the planet carrier of the first basic planetary gear train unit and the planet carrier of the second basic planetary gear train unit;

[0012] a third brake connected to the sun gear of the fourth basic planetary gear train unit;

[0013] Three combinations of the first clutch, the second clutch, the third clutch, the first brake, the second brake and the third brake are selectively engaged to establish eight forward speed ratios and one reverse speed ratio between the input shaft and the output shaft.

[0014] Further, the input shaft is connected to the sun gear of the second basic planetary gear train unit and the ring gear of the first basic planetary gear train unit through a third transmission member; the input shaft is connected to the planet carrier of the first basic planetary gear train unit and the planet carrier of the second basic planetary gear train unit through a second transmission member, and the ring gear of the second basic planetary gear train unit is connected to the sun gear of the third basic planetary gear train unit through a fourth transmission member; the input shaft is connected to the planet carrier of the third basic planetary gear train unit and the ring gear of the fourth basic planetary gear train unit through a fifth transmission member, and the ring gear of the third basic planetary gear train unit and the planet carrier of the fourth basic planetary gear train unit are both connected to the output member, and the output member is connected to the output shaft.

[0015] Further, the first clutch is connected to the third transmission member, the second clutch is connected to the second transmission member, and the third clutch is connected to the fifth transmission member.

[0016] Furthermore, the first brake is connected to the first transmission member; the second brake is connected to the second transmission member; and the third brake is connected to the sixth transmission member.

[0017] Furthermore, the eight-speed automatic transmission has eight gear ratios of four reduction gears, one direct gear and three overdrive gears.

[0018] Further, by engaging the first clutch, the first brake and the third brake, a first gear ratio is established between the input shaft and the output shaft;

[0019] establishing a second gear ratio between the input shaft and the output shaft by engaging the second clutch, the first brake, and the third brake;

[0020] establishing a third gear ratio between the input shaft and the output shaft by engaging the first clutch, the second clutch, and the third brake;

[0021] establishing a fourth gear ratio between the input shaft and the output shaft by engaging the first clutch, the third clutch, and the third brake;

[0022] establishing a fifth gear ratio between the input shaft and the output shaft by engaging the first clutch, the second clutch, and the third clutch;

[0023] establishing a sixth gear ratio between the input shaft and the output shaft by engaging the second clutch, the third clutch, and the first brake;

[0024] establishing a seventh gear ratio between the input shaft and the output shaft by engaging the first clutch, the third clutch, and the first brake;

[0025] An eighth gear ratio is established between the input shaft and the output shaft by engaging the third clutch, the first brake and the second brake.

[0026] Further, a reverse gear ratio is established between the input shaft and the output shaft by engaging the first clutch, the second brake and the third brake.

[0027] Furthermore, the first clutch, the second clutch and the third clutch are all multi-plate wet clutches.

[0028] Furthermore, the first brake, the second brake and the third brake are all multi-disc wet brakes.

[0029] Furthermore, the first brake, the second brake and the third brake are all fixed on the transmission housing.

[0030] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0031] (1) The present invention provides an eight-speed automatic transmission with smooth transmission, which consists of an 11-bar 2-DOF planetary gear train, three clutches and three brakes, has a simple structure, a reasonable transmission ratio of each gear, and a step ratio between gears within a reasonable range. It has fewer control elements, high transmission efficiency, simple control of clutches and brakes, and excellent overall performance. It is beneficial to reduce the size, weight and manufacturing cost of the automatic transmission.

[0032] (2) The control of the working state of the clutch and the brake in the present invention is simple, and satisfies the "single conversion principle", that is, when two adjacent gears are switched, only the working state of one clutch or brake needs to be changed, which reduces the control difficulty of the transmission. The step ratio between the gears is stable, and the gear shifting is smooth.

[0033] (3) The present invention uses only six control elements in the arrangement of control elements, thereby improving the power of the vehicle and reducing fuel consumption, reducing the speed ratio interval between adjacent gears, and making gear shifting smooth and responsive; at the same time, it improves the smoothness of vehicle driving, simplifies the overall structure of the transmission, reduces weight, and is conducive to energy saving and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of an eight-speed automatic transmission with smooth transmission according to the present invention;

[0035] Figure 2 The present invention is an operational logic diagram of an eight-speed automatic transmission with smooth transmission.

[0036] In the figure: 1, the first basic planetary gear train unit; 11, the ring gear of the first basic planetary gear train unit; 12, the planetary gear of the first basic planetary gear train unit; 13, the planet carrier of the first basic planetary gear train unit; 14, the sun gear of the first basic planetary gear train unit; 2, the second basic planetary gear train unit; 21, the ring gear of the second basic planetary gear train unit; 22, the planetary gear of the second basic planetary gear train unit; 23, the planet carrier of the second basic planetary gear train unit; 24, the sun gear of the second basic planetary gear train unit; 3, the third basic planetary gear train unit; 31, the ring gear of the third basic planetary gear train unit; 32, the planetary gear of the third basic planetary gear train unit; 33, the planet carrier of the third basic planetary gear train unit; 34, the sun gear of the third basic planetary gear train unit Element's sun gear; 4. Fourth basic planetary gear train unit; 41. Ring gear of fourth basic planetary gear train unit; 42. Planetary gear of fourth basic planetary gear train unit; 43. Planet carrier of fourth basic planetary gear train unit; 44. Sun gear of fourth basic planetary gear train unit; 5. Torque transmission device; 51. First transmission member; 52. Second transmission member; 53. Third transmission member; 54. Fourth transmission member; 55. Fifth transmission member; 56. Sixth transmission member; 57. Output member; C1. First clutch; C2. Second clutch; C3. Third clutch; B1. First brake; B2. Second brake; B3. Third brake; 6. 11-rod 2-DOF separable planetary gear train; 7. Input shaft; 8. Output shaft. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings. The following is a preferred embodiment of the present invention, which is intended to provide a basic understanding of the present invention, but is not intended to confirm the key or decisive elements of the present invention or to limit the scope of protection.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "fixed connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, it can be an electrical connection, it can be a direct connection, it can be an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Please refer to Figure 1An embodiment of the present invention provides an eight-speed automatic transmission with smooth transmission, including a transmission housing 9; and an input shaft 7, an output shaft 8, an 11-rod 2-degree-of-freedom separable planetary gear system 6 and a torque transmission device 5 installed inside the transmission housing 9.

[0040] The 11-rod 2-DOF separable planetary gear train 6 includes four basic planetary gear train units arranged in sequence from the input shaft 7 to the output shaft 8, namely, a first basic planetary gear train unit 1, a second basic planetary gear train unit 2, a third basic planetary gear train unit 3 and a fourth basic planetary gear train unit 4.

[0041] Each basic planetary gear train unit includes a ring gear, planet gears, a planet carrier and a sun gear.

[0042] Specific:

[0043] The sun gear 14 of the first basic planetary gear train unit and the planetary gear 12 of the first basic planetary gear train unit are externally meshed for transmission, the planetary gear 12 of the first basic planetary gear train unit and the ring gear 11 of the first basic planetary gear train unit are internally meshed for transmission, and the planetary gear 12 of the first basic planetary gear train unit is rotatably supported on the planet carrier 13 of the first basic planetary gear train unit.

[0044] The sun gear 24 of the second basic planetary gear unit and the planetary gear 22 of the second basic planetary gear unit are externally meshed for transmission, the planetary gear 22 of the second basic planetary gear unit and the ring gear 21 of the second basic planetary gear unit are internally meshed for transmission, and the planetary gear 22 of the second basic planetary gear unit is rotatably supported on the planet carrier 23 of the second basic planetary gear unit.

[0045] The sun gear 34 of the third basic planetary gear train unit and the planetary gear 32 of the third basic planetary gear train unit are externally meshed for transmission, the planetary gear 32 of the third basic planetary gear train unit and the ring gear 31 of the third basic planetary gear train unit are internally meshed for transmission, and the planetary gear 32 of the third basic planetary gear train unit is rotatably supported on the planet carrier 33 of the third basic planetary gear train unit.

[0046] The sun gear 44 of the fourth basic planetary gear train unit and the planetary gear 42 of the fourth basic planetary gear train unit are externally meshed for transmission, the planetary gear 42 of the fourth basic planetary gear train unit and the ring gear 41 of the fourth basic planetary gear train unit are internally meshed for transmission, and the planetary gear 42 of the fourth basic planetary gear train unit is rotatably supported on the planet carrier 43 of the fourth basic planetary gear train unit.

[0047] The planet carrier 13 of the first basic planetary gear train unit is fixedly connected to the planet carrier 23 of the second basic planetary gear train unit; the ring gear 11 of the first basic planetary gear train unit is fixedly connected to the sun gear 24 of the second basic planetary gear train unit; the ring gear 21 of the second basic planetary gear train unit is fixedly connected to the sun gear 34 of the third basic planetary gear train unit; the planet carrier 33 of the third basic planetary gear train unit is fixedly connected to the ring gear 41 of the fourth basic planetary gear train unit; the ring gear 31 of the third basic planetary gear train unit is fixedly connected to the planet carrier 43 of the fourth basic planetary gear train unit, and the ring gear 31 of the third basic planetary gear train unit and the planet carrier 43 of the fourth basic planetary gear train unit are both fixedly connected to the output shaft 8.

[0048] The torque transmission device includes three clutches and three brakes. The three clutches are respectively a first clutch C1, a second clutch C2 and a third clutch C3, and the three brakes are respectively a first brake B1, a second brake B2 and a third brake B3.

[0049] A first clutch C1, which connects the input shaft 7 to the sun gear 24 of the second basic planetary gear train unit and the ring gear 11 of the first basic planetary gear train unit;

[0050] A second clutch C2, which connects the input shaft 7 to the planet carrier 13 of the first basic planetary gear train unit and the planet carrier 23 of the second basic planetary gear train unit;

[0051] A third clutch C3, which connects the input shaft 7 to the planet carrier 33 of the third basic planetary gear train unit and the ring gear 41 of the fourth basic planetary gear train unit;

[0052] A first brake B1 connected to the sun gear 14 of the first basic planetary gear train unit;

[0053] A second brake B2, which connects the planet carrier 13 of the first basic planetary gear train unit and the planet carrier 23 of the second basic planetary gear train unit;

[0054] A third brake B3 connected to the sun gear 44 of the fourth basic planetary gear train unit;

[0055] Three combinations of the first clutch C1, the second clutch C2, the third clutch C3, the first brake B1, the second brake B2 and the third brake B3 are selectively engaged to establish eight forward gear ratios and one reverse gear ratio between the input shaft 7 and the output shaft 8.

[0056] In this embodiment, the input shaft 7 is connected to the sun gear 24 of the second basic planetary gear train unit and the ring gear 11 of the first basic planetary gear train unit through the third transmission member 53; the input shaft 7 is connected to the planet carrier 13 of the first basic planetary gear train unit and the planet carrier 23 of the second basic planetary gear train unit through the second transmission member 52, and the ring gear 21 of the second basic planetary gear train unit is connected to the sun gear 34 of the third basic planetary gear train unit through the fourth transmission member 54; the input shaft 7 is connected to the planet carrier 33 of the third basic planetary gear train unit and the ring gear 41 of the fourth basic planetary gear train unit through the fifth transmission member 55, and the ring gear 31 of the third basic planetary gear train unit and the planet carrier 43 of the fourth basic planetary gear train unit are both connected to the output member 57, and the output member 57 is connected to the output shaft 8.

[0057] In this embodiment, the structural features of the three clutches in the transmission are as follows: the first clutch C1 is connected to the third transmission member 53 , the second clutch C2 is connected to the second transmission member 52 , and the third clutch C3 is connected to the fifth transmission member 55 .

[0058] In this embodiment, the structural features of the three brakes in the transmission are as follows: the first brake B1 is connected to the first transmission member 51 ; the second brake B2 is connected to the second transmission member 52 ; and the third brake B3 is connected to the sixth transmission member 56 .

[0059] The input shaft 7 is connected to the third transmission member 53, the second transmission member 52 and the fifth transmission member 55 through the first clutch C1, the second clutch C2 and the third clutch C3. The input shaft is connected to the generator through the torque converter, and the power provided by the generator is transmitted to the input shaft through the torque converter.

[0060] The output shaft 7 is connected to the vehicle drive wheels through a differential to transmit the output power to the vehicle drive wheels.

[0061] In the present embodiment, the first clutch C1, the second clutch C2 and the third clutch C3 are all multi-plate wet clutches. When the active plate and the driven plate of the clutch are pressed tightly under the action of hydraulic pressure, the clutch is engaged and is in a working state. At this time, the movable components connected to both ends of the clutch are engaged and have the same rotation speed; conversely, when the clutch is in a non-working state, the movable components connected to both ends of the clutch are separated and have different rotation speeds.

[0062] In this embodiment, the first brake B1, the second brake B2 and the third brake B3 are all multi-disc wet brakes used to connect the transmission member and the transmission housing. When the brake is in working state, the transmission member is engaged with the transmission housing, the transmission member cannot rotate, and is in a braking state.

[0063] The eight forward gears of the present invention are four reduction gears, one direct gear and three overdrive gears, as follows:

[0064] By engaging the first clutch C1, the first brake B1 and the third brake B3, a first gear ratio is established between the input shaft 7 and the output shaft 8;

[0065] By engaging the second clutch C2, the first brake B1 and the third brake B3, a second gear ratio is established between the input shaft 7 and the output shaft 8;

[0066] By engaging the first clutch C1, the second clutch C2 and the third brake B3, a third gear ratio is established between the input shaft 7 and the output shaft 8;

[0067] By engaging the first clutch C1, the third clutch C3 and the third brake B3, a fourth gear ratio is established between the input shaft 7 and the output shaft 8;

[0068] By engaging the first clutch C1, the second clutch C2 and the third clutch C3, a fifth gear ratio is established between the input shaft 7 and the output shaft 8;

[0069] By engaging the second clutch C2, the third clutch C3 and the first brake B1, a sixth gear ratio is established between the input shaft 7 and the output shaft 8;

[0070] By engaging the first clutch C1, the third clutch C3 and the first brake B1, a seventh gear ratio is established between the input shaft 7 and the output shaft 8;

[0071] By engaging the third clutch C3 , the first brake B1 and the second brake B2 , an eighth gear ratio is established between the input shaft 7 and the output shaft 8 .

[0072] The transmission of the present invention can also achieve a reverse gear by engaging the first clutch C1 , the second brake B2 and the third brake B3 to establish a reverse gear ratio between the input shaft 7 and the output shaft 8 .

[0073] The transmission ratio of an automatic transmission mechanism is the ratio of the rotational speed of an input member to that of an output member. The automatic transmission mechanism of the present invention can achieve 9 different transmission ratios, i.e., 9 gears, including 8 forward gears and 1 reverse gear. Each gear can be achieved by controlling the working state of the clutch and the brake.

[0074] refer to Figure 1 And such as Figure 2 The specific implementation process of each gear ratio of the transmission is as follows:

[0075] (1) The first gear is a deceleration gear, and the transmission ratio is greater than 1. The first clutch C1, the first brake B1 and the third brake B3 are in the working state, and the other clutches and brakes are in the non-working state. Due to the action of the clutch C1, the third transmission member 53 rotates together with the input shaft as a whole, and the third transmission member 53 is the input member. Due to the action of the first brake B1 and the third brake B3, the first transmission member 51 and the sixth transmission member 56 are in the braking state, and the rotation speed is 0. The power is transmitted from the input member (third transmission member) 53. In the first basic planetary gear train unit 1, the third transmission member 53 drives the planetary gear 12 of the first basic planetary gear train unit 1 to rotate, thereby driving the second transmission member 52 to rotate; in the second basic planetary gear train unit 2, the third transmission member 53 and the second transmission member 52 jointly drive the planetary gear 22 of the second basic planetary gear train unit 2 to rotate, thereby driving the fourth transmission member 54 to rotate; in the third basic planetary gear train unit 3, the fourth transmission member 54 drives the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, thereby driving the fifth transmission member 55 to rotate; in the fourth basic planetary gear train unit 4, the fifth transmission member 55 drives the planetary gear 42 of the fourth basic planetary gear train unit 4 to rotate. At this time, the planetary gear 32 of the third basic planetary gear train unit 3 and the planetary gear 42 of the fourth basic planetary gear train unit 4 rotate together, thereby driving the output member 57 to rotate, and transmitting the power to the output member 57. The speed of the output member 57 is lower than that of the input member (third transmission member) 53, and is in the lower first gear.

[0076] (2) The 2nd gear is a deceleration gear, and the transmission ratio is greater than 1. The second clutch C2, the first brake B1 and the third brake B3 are in the working state, and the other clutches and brakes are in the non-working state. Due to the action of the second clutch C2, the second transmission member 52 rotates together with the input shaft as a whole, and the second transmission member 52 is the input member. Due to the action of the first brake B1 and the second brake B3, the first transmission member 51 and the sixth transmission member 56 are in the braking state, and the rotation speed is 0. The power is transmitted from the input member (second transmission member) 52. In the first basic planetary gear train unit 1, the second transmission member 52 drives the planetary gear 12 of the first basic planetary gear train unit 1 to rotate, and then drives the third transmission member 53 to rotate; in the second basic planetary gear train unit 2, the third transmission member 53 and the second transmission member 52 jointly drive the planetary gear 22 of the second basic planetary gear train unit 2 to rotate, and then drives the fourth transmission member 54 to rotate; in the third basic planetary gear train unit 3, the fourth transmission member 54 drives the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drives the fifth transmission member 55 to rotate; in the fourth basic planetary gear train unit 4, the fifth transmission member 55 drives the planetary gear 42 of the fourth basic planetary gear train unit 4 to rotate. At this time, the planetary gear 32 of the third basic planetary gear train unit 3 and the planetary gear 42 of the fourth basic planetary gear train unit 4 rotate together, and then drive the output member 57 to rotate, and transmit the power to the output member 57. The speed of the output member 57 is lower than the speed of the input member (second transmission member) 52, and is in the second gear which is higher than the first gear.

[0077] (3) The third gear is a deceleration gear, with a transmission ratio greater than 1. The first clutch C1, the second clutch C2 and the third brake B3 are in working state, and the other clutches and brakes are in non-working state. Due to the action of the first clutch C1 and the second clutch C2, the third transmission member 53 and the second transmission member 52 are both input members, and the power is simultaneously transmitted from the third transmission member 53 and the second transmission member 52, driving the first basic planetary gear train unit 1 and the second basic planetary gear train unit 2 to rotate as a whole, and then driving the fourth transmission member 54 to rotate, and its speed is equal to the speed of the input shaft. Due to the action of the third brake B3, the sixth transmission member 56 is in a braking state, and the speed is 0. In the third basic planetary gear train unit 3, the fourth transmission member 54 drives the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drives the fifth transmission member 55 to rotate; in the fourth basic planetary gear train unit 4, the fifth transmission member 55 drives the planetary gear 42 of the fourth basic planetary gear train unit 4 to rotate, at this time, the planetary gear 32 of the third basic planetary gear train unit 3 and the planetary gear 42 of the fourth basic planetary gear train unit 4 rotate together, and then drive the output member 57 to rotate, and transmit power to the output member 57. The speed of the output member 57 is lower than the speed of the input member (third transmission member) 53 and the input member (second transmission member) 52, and is in the third gear with a higher speed than the second gear.

[0078] (4) The 4th gear is a deceleration gear, with a transmission ratio greater than 1. The first clutch C1, the third clutch C3 and the third brake B3 are in working state, and the other clutches and brakes are in non-working state. Due to the action of the first clutch C1 and the third clutch C3, the third transmission member 53 and the fifth transmission member 55 are both input members, and power is transmitted from the third transmission member 53 and the fifth transmission member 55 at the same time. Due to the action of the third brake B3, the sixth transmission member 56 is in a braking state, and the speed is 0. In the fourth basic planetary gear train unit 4, the fifth transmission member 55 drives the planetary gear 42 of the fourth basic planetary gear train unit 4 to rotate, and then drives the output member 57 to rotate, and transmits power to the output member 57. The speed of the output member 57 is lower than the speed of the input member (fifth transmission member) 55, and is in the 4th gear with a higher speed than the 3rd gear.

[0079] (5) The fifth gear is a direct gear, with a transmission ratio of 1. The first clutch C1, the second clutch C2 and the third clutch C3 are in operation, and the other brakes are in non-operation. Due to the action of the first clutch C1, the second clutch C2 and the third clutch C3, the third transmission member 53, the second transmission member 52 and the fifth transmission member 55 are all input members. Power is simultaneously transmitted from the third transmission member 53, the second transmission member 52 and the fifth transmission member 55, driving the entire mechanism to rotate as a whole. Therefore, the input member and the output member have the same rotation speed, and the gear is in a direct gear.

[0080] (6) The 6th gear is an overdrive gear, with a transmission ratio less than 1. The second clutch C2, the third clutch C3 and the first brake B1 are in operation, and the other clutches and brakes are in non-operation. Due to the action of the second clutch C2 and the third clutch C3, the second transmission member 52 and the fifth transmission member 55 are both input members, and power is transmitted from the second transmission member 52 and the fifth transmission member 55 at the same time. Due to the action of the first brake B1, the first transmission member 51 is in a braking state, and the speed is 0. In the first basic planetary gear train unit 1, the second transmission member 52 drives the planetary gear 12 of the first basic planetary gear train unit 1 to rotate, and then drives the third transmission member 53 to rotate; in the second basic planetary gear train unit 2, the third transmission member 53 and the second transmission member 52 jointly drive the planetary gear 22 of the second basic planetary gear train unit 2 to rotate, and then drives the fourth transmission member 54 to rotate; in the third basic planetary gear train unit 3, the fourth transmission member 54 and the fifth transmission member 55 jointly drive the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drives the output member 57 to rotate, and transmits power to the output member 57. The rotation speed of the output member 57 is greater than the rotation speeds of the input member (second transmission member) 52 and the input member (fifth transmission member) 55 , and is in the sixth gear with a relatively high rotation speed.

[0081] (7) The 7th gear is an overdrive gear, with a transmission ratio less than 1. The first clutch C1, the third clutch C3 and the first brake B1 are in operation, and the other clutches and brakes are in non-operation. Due to the action of the first clutch C1 and the third clutch C3, the third transmission member 53 and the fifth transmission member 55 are both input members, and power is transmitted from the third transmission member 53 and the fifth transmission member 55 at the same time. Due to the action of the first brake B1, the first transmission member 51 is in a braking state, and the speed is 0. In the first basic planetary gear train unit 1, the third transmission member 53 drives the planetary gear 12 in the first basic planetary gear train unit 1 to rotate, and then drives the second transmission member 52 to rotate; in the second basic planetary gear train unit 2, the third transmission member 53 and the second transmission member 52 jointly drive the planetary gear 22 of the second basic planetary gear train unit 2 to rotate, and then drive the fourth transmission member 54 to rotate; in the third basic planetary gear train unit 3, the fourth transmission member 54 and the fifth transmission member 55 jointly drive the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drive the output member 57 to rotate, and transmit the power to the output member 57. The rotation speed of the output member 57 is greater than the rotation speeds of the input member (third transmission member) 53 and the input member (fifth transmission member) 55 , and is in the seventh gear which is higher than the sixth gear.

[0082] (8) The 8th gear is an overdrive gear, with a transmission ratio less than 1. The third clutch C3, the first brake B1 and the second brake B2 are in operation, and the other clutches and brakes are in non-operation. Due to the action of the third clutch C3, the fifth transmission member 55 rotates together with the input shaft as a whole, and the fifth transmission member 55 is an input member. Due to the action of the first brake B1 and the second brake B2, the first transmission member 51 and the second transmission member 52 are in a braking state, and the speed is 0. In the third basic planetary gear train unit 3, the fifth transmission member 55 drives the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drives the output member 57 to rotate, and transmits power to the output member 57. The speed of the output member 57 is greater than the speed of the input member (fifth transmission member) 55, and is in the 8th gear with a higher speed than the 7th gear.

[0083] (9) The 9th gear is the reverse gear. The first clutch C1, the second brake B2 and the third brake B3 are in the working state, and the other clutches and brakes are in the non-working state. Due to the action of the first clutch C1, the third transmission member 53 rotates together with the input shaft as a whole, and the third transmission member 53 is the input member. Due to the action of the second brake B2 and the third brake B3, the second transmission member 52 and the sixth transmission member 56 are in the braking state, and the rotation speed is 0. In the second basic planetary gear train unit 2, the third transmission member 53 drives the planetary gear 22 of the second basic planetary gear train unit 2 to rotate, and then drives the fourth transmission member 54 to rotate; in the third basic planetary gear train unit 3, the fourth transmission member 54 drives the planetary gear 32 of the third basic planetary gear train unit 3 to rotate, and then drives the fifth transmission member 55 to rotate; in the fourth basic planetary gear train unit 4, the fifth transmission member 55 drives the planetary gear 42 of the fourth basic planetary gear train unit 4 to rotate, at this time, the planetary gear 32 of the third basic planetary gear train unit 3 and the planetary gear 42 of the fourth basic planetary gear train unit 4 rotate together, and then drive the output member 57 to rotate, and transmit power to the output member 57. The rotation direction of the output member 57 is opposite to the rotation direction of the input member (third transmission member) 53, and is in reverse gear.

[0084] In the present invention, the characteristic parameter K of the basic planetary gear train unit is the gear ratio between the ring gear and the sun gear. The relationship between the transmission ratio of each gear and the characteristic parameter is shown in Table 1.

[0085] In order to make each gear have a higher transmission efficiency, the characteristic parameters of the four basic planetary gear train units in the mechanism are K1 = 1.5, K2 = 2.0, K3 = 1.5 and K4 = 2.5, and the transmission ratios of each gear calculated are 5, 3, 2, 1.4, 1, 0.82, 0.71, 0.6, -4. The implementation methods of each gear are summarized as follows Figure 2 shown.

[0086] Table 1. Relationship between transmission ratio and characteristic parameters

[0087]

[0088] The control of the working state of the clutch and the brake in the present invention is simple, and satisfies the "single conversion principle", that is, when two adjacent gears are switched, only the working state of one clutch or brake needs to be changed, which reduces the control difficulty of the transmission. The step ratio between the gears is stable, and the gear shifting is smooth.

[0089] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An eight-speed automatic transmission with smooth transmission, comprising a transmission housing (9); and an input shaft (7), an output shaft (8) and a torque transmission device (5) installed inside the transmission housing, characterized in that: The invention also comprises an 11-rod 2-DOF separable planetary gear train (6), wherein the 11-rod 2-DOF separable planetary gear train (6) comprises four basic planetary gear train units arranged in sequence along the direction from the input shaft (7) to the output shaft (8), namely a first basic planetary gear train unit (1), a second basic planetary gear train unit (2), a third basic planetary gear train unit (3) and a fourth basic planetary gear train unit (4), each of the basic planetary gear train units comprising a ring gear, a planetary gear, a planet carrier and a sun gear; the planet carrier (13) of the first basic planetary gear train unit is fixedly connected to the planet carrier (23) of the second basic planetary gear train unit; the first The ring gear (11) of the basic planetary gear train unit is fixedly connected to the sun gear (24) of the second basic planetary gear train unit; the ring gear (21) of the second basic planetary gear train unit is fixedly connected to the sun gear (34) of the third basic planetary gear train unit; the planet carrier (33) of the third basic planetary gear train unit is fixedly connected to the ring gear (41) of the fourth basic planetary gear train unit; the ring gear (31) of the third basic planetary gear train unit is fixedly connected to the planet carrier (43) of the fourth basic planetary gear train unit, and the ring gear (31) of the third basic planetary gear train unit and the planet carrier (43) of the fourth basic planetary gear train unit are both fixedly connected to the output shaft (8); The torque transmission device comprises: a first clutch (C1) which connects the input shaft (7) to the ring gear (11) of the first basic planetary gear train unit and the sun gear (24) of the second basic planetary gear train unit; a second clutch (C2) connecting the input shaft (7) to the planet carrier (13) of the first basic planetary gear train unit and the planet carrier (23) of the second basic planetary gear train unit; a third clutch (C3) which connects the input shaft (7) to the planet carrier (33) of the third basic planetary gear train unit and the ring gear (41) of the fourth basic planetary gear train unit; a first brake (B1) connected to the sun gear (14) of the first basic planetary gear train unit; a second brake (B2) connecting the planet carrier (13) of the first basic planetary gear train unit and the planet carrier (23) of the second basic planetary gear train unit; a third brake (B3) connected to the sun gear (44) of the fourth basic planetary gear train unit; Three combinations of the first clutch (C1), the second clutch (C2), the third clutch (C3), the first brake (B1), the second brake (B2) and the third brake (B3) are selectively engaged to establish eight forward gear ratios and one reverse gear ratio between the input shaft (7) and the output shaft (8).

2. The eight-speed automatic transmission according to claim 1, characterized in that: The input shaft (7) is connected to the sun gear (24) of the second basic planetary gear train unit and the ring gear (11) of the first basic planetary gear train unit through a third transmission member (53); the input shaft (7) is connected to the planet carrier (13) of the first basic planetary gear train unit and the planet carrier (23) of the second basic planetary gear train unit through a second transmission member (52); the ring gear (21) of the second basic planetary gear train unit is connected to the sun gear (34) of the third basic planetary gear train unit through a fourth transmission member (54); the input shaft (7) is connected to the planet carrier (33) of the third basic planetary gear train unit and the ring gear (41) of the fourth basic planetary gear train unit through a fifth transmission member (55); the ring gear (31) of the third basic planetary gear train unit and the planet carrier (43) of the fourth basic planetary gear train unit are both connected to an output member (57); and the output member (57) is connected to the output shaft (8).

3. The eight-speed automatic transmission according to claim 2, characterized in that: The first clutch (C1) is connected to the third transmission member (53), the second clutch (C2) is connected to the second transmission member (52), and the third clutch (C3) is connected to the fifth transmission member (55).

4. The eight-speed automatic transmission according to claim 3, characterized in that: The first brake (B1) is connected to the first transmission member (51); the second brake (B2) is connected to the second transmission member (52); and the third brake (B3) is connected to the sixth transmission member (56).

5. The eight-speed automatic transmission according to claim 4, characterized in that: The eight-speed automatic transmission has eight gear ratios of four reduction gears, one direct gear and three overdrive gears.

6. The eight-speed automatic transmission according to claim 5, characterized in that: By engaging the first clutch (C1), the first brake (B1) and the third brake (B3), a first gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the second clutch (C2), the first brake (B1) and the third brake (B3), a second gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the first clutch (C1), the second clutch (C2) and the third brake (B3), a third gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the first clutch (C1), the third clutch (C3) and the third brake (B3), a fourth gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the first clutch (C1), the second clutch (C2) and the third clutch (C3), a fifth gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the second clutch (C2), the third clutch (C3) and the first brake (B1), a sixth gear ratio is established between the input shaft (7) and the output shaft (8); By engaging the first clutch (C1), the third clutch (C3) and the first brake (B1), a seventh gear ratio is established between the input shaft (7) and the output shaft (8); An eighth gear ratio is established between the input shaft (7) and the output shaft (8) by engaging the third clutch (C3), the first brake (B1) and the second brake (B2).

7. The eight-speed automatic transmission according to claim 6, characterized in that: A reverse gear ratio is established between the input shaft (7) and the output shaft (8) by engaging the first clutch (C1), the second brake (B2) and the third brake (B3).

8. The eight-speed automatic transmission according to claim 7, characterized in that: The first clutch (C1), the second clutch (C2) and the third clutch (C3) are all multi-plate wet clutches.

9. The eight-speed automatic transmission according to claim 8, characterized in that: The first brake (B1), the second brake (B2) and the third brake (B3) are all multi-disc wet brakes.

10. The eight-speed automatic transmission according to claim 9, characterized in that: The first brake (B1), the second brake (B2) and the third brake (B3) are all fixed on the transmission housing (9).

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