CN107524767A - Three planet row automatic transmission and vehicle - Google Patents

Abstract

The invention relates to the field of automobiles, and discloses a three-planetary automatic transmission and a vehicle, including an input member and an output member, first, second and third planetary rows, first, second and third clutches and first and third clutches. Two brakes, wherein the first planetary row is a double planetary gear set planetary row, the second and third planetary row are single planetary gear set planetary row; the first sun gear is fixed, and the first ring gear is connected to the output through the first clutch component connection, the first planetary carrier is fixedly connected to the second planetary carrier, the second ring gear is fixedly connected to the third planetary carrier, the input member is fixedly connected to the second sun gear, the input member is connected to the third sun gear through the third clutch, The second clutch is closed to make the second planetary row rotate as a whole; the third planetary carrier is connected to the casing through the first brake, and the third sun gear is connected to the casing through the second brake.

Description

Three planetary automatic transmission and vehicle

technical field

The invention relates to the field of automobiles, in particular to a three-planetary automatic transmission and a vehicle.

Background technique

The gear train mechanism of the electronically controlled hydraulic transmission generally includes multiple planetary arrays, and the engine power is transmitted to the planetary gear transmission mechanism through the hydraulic torque converter for gear shifting and then output. The volume, weight, efficiency and carrying capacity of the automatic transmission are directly related to the layout of the planetary row structure. The more gears of the automatic transmission drive train, the lower the fuel consumption of the car and the better the economy. However, as the number of gears increases, the number of planetary rows and the number of operating clutches and brakes also increase, and it is even more difficult to achieve a design that satisfies the theoretical step ratio.

At present, the schemes of six-speed automatic transmissions used in the passenger car market are mainly: (1) Lape Lajie schemes used by Aisin, ZF (ZF) and Geely (DSI); (2) Hyundai A6MF and A6LF (3) The scheme used by the GM 6T series; (4) The six-speed scheme used by Mazda Chuangchi Lantian.

However, the Lepe Leger scheme is realized by adding a planetary row on the basis of the Lavina four-speed automatic transmission, which cannot realize direct gearing;

The scheme of the six-speed automatic transmission used in modern and general use contains two clutches and three brakes. The number of brakes is relatively large. During the manufacturing process of the transmission, the friction steel teeth of the brakes are finally connected to the case. The manufacturing process More complex, more brakes will undoubtedly increase the difficulty of processing and manufacturing the box, and the box material of the transmission is generally aluminum alloy, more brakes will undoubtedly make the lightweight design of the box while ensuring the strength of the box. difficulty;

The six-speed scheme used by Chuangchi Lantian is derived from the horizontal layout scheme matching the six-speed scheme used on heavy-duty diesel locomotives. In terms of matching with gasoline locomotives, it has inherently insufficient characteristics in terms of the speed ratio configuration that can be realized.

Contents of the invention

The purpose of the present invention is to provide a three-planetary automatic transmission that can realize six speed ratio outputs by using only two brakes on the premise of using five operating elements, so as to reduce the manufacturing difficulty of the transmission case and make the case The body can ensure the strength while improving the feasibility of the lightweight design of the box body.

In order to achieve the above object, the present invention provides a three-planetary automatic transmission, which includes an input member and an output member, the first, second and third planetary rows arranged in sequence along the same rotary shaft, the first, second and third Three clutches and first and second brakes, wherein the first planetary row includes a first ring gear, a first inner planetary gear set and a first outer planetary gear set meshing with each other, a first sun gear and a first planet carrier ; The second planetary row includes the second ring gear, the second planetary gear set, the second sun gear and the second planet carrier; the third planetary row includes the third ring gear, the third planetary gear set, the third sun gear wheel and the third planet carrier; the first sun gear is fixed, the first ring gear is connected to the output member through the first clutch, and the first planet carrier is fixed to the second planet carrier connected, the second ring gear is fixedly connected to the third planet carrier, the input member is fixedly connected to the second sun gear, and the input member is connected to the third sun gear through the third clutch , the second clutch is disposed on the second planetary row, the second clutch is selectively closed so that the second planetary row and the input member rotate integrally; the first brake is selectively closed, to brake the third planet carrier, and the second brake is selectively closed to brake the third sun gear.

As a preferred solution, the second clutch is arranged between the second ring gear and the second sun gear, and the second ring gear is connected to the second sun gear through the second clutch.

As a preferred solution, the second clutch is arranged between the second planet carrier and the second sun gear, and the second planet carrier is connected to the second sun gear through the second clutch.

As a preferred solution, the first sun gear is fixedly connected to the case of the transmission.

As a preferred solution, in the first planetary row, the first sun gear is externally meshed with the first inner planetary gear set, and the first inner planetary gear set is externally meshed with the first outer planetary gear set , the first outer planetary gear set is internally meshed with the first ring gear, and both the first inner planetary gear set and the first outer planetary gear set are mounted on pin shafts at corresponding positions of the first planet carrier through bearings.

As a preferred solution, in the second planetary row, the second sun gear and the second planetary gear set are externally meshed, the second planetary gear set is internally meshed with the second ring gear, and the second planetary gear set is installed on the second planet carrier through bearings On the pin shaft; in the third planetary row, the third sun gear and the third planetary gear set are externally meshed, the third planetary gear set is internally meshed with the third ring gear, and the third planetary gear set is installed on the third planetary gear through bearings on the pin shaft of the rack.

As a preferred solution, one end of the first brake is connected to the case of the transmission, and the other end is connected to the third planet carrier; one end of the second brake is connected to the case of the transmission, and the other end is connected to the third planet carrier. Sun wheel connection.

As a preferred solution, the first, second and third clutches are all multi-plate wet clutches or dog clutches.

As a preferred solution, when the first clutch and the first brake are closed simultaneously, a first forward speed ratio can be generated between the input member and the output member; when the first clutch and the second When the brakes are simultaneously closed, a second forward speed ratio can be generated between the input member and the output member; A third forward speed ratio is produced between the first and second clutches; a fourth forward speed ratio is produced between the input member and the output member when the first clutch and the second clutch are simultaneously closed; when the second clutch When the third clutch is closed simultaneously, a fifth forward speed ratio can be produced between the input member and the output member; when the second brake is closed simultaneously with the second clutch, the input A sixth forward speed ratio is created between the input member and the output member; a reverse speed ratio is created between the input member and the output member when the first brake and the third clutch are simultaneously closed.

In order to solve the same problem, the present invention also provides a vehicle comprising the three-planetary automatic transmission of any one of the solutions above.

The three-planetary automatic transmission of the present invention adopts three clutches and two brakes as the connection scheme of operating elements combined with three planetary rows, and can realize multiple combinations of selectively closing only two operating elements In this way, multiple (six forward speed ratios and one reverse speed ratio) speed ratio conversions can be generated; and relatively few (two) brakes are used as operating elements, which can greatly reduce the difficulty of processing and manufacturing the box. In the case of the strength of the body, it is beneficial to the lightweight design and manufacture of the box; in addition, the use of more clutches can facilitate the nesting design of the clutches, making the structure of the transmission more compact, and it is beneficial to cut off the gearbox in a specific gear. The connection relationship among the planetary rows makes the redundant planetary rows idle without carrying torque or participating in rotation, so as to reduce the drag torque of the planetary rows and improve the transmission efficiency of the transmission.

Description of drawings

Fig. 1 is a schematic diagram of the connecting structure of each member of a three-planetary automatic transmission of a preferred embodiment of the present invention;

Fig. 2 is the connection structure schematic diagram of each component of the three-planetary automatic transmission of another preferred embodiment of the present invention;

Fig. 3 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the first forward speed ratio;

Fig. 4 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the second forward speed ratio;

Fig. 5 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the third forward speed ratio;

Fig. 6 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the fourth forward speed ratio;

Fig. 7 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the fifth forward speed ratio;

Fig. 8 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in Fig. 1 realizes the sixth forward speed ratio;

FIG. 9 is a schematic diagram of the power transmission route when the three-planetary automatic transmission shown in FIG. 1 realizes the reverse speed ratio.

Among them, 1. The first planetary row; 11. The first sun gear; 12. The first ring gear; 13. The first planet carrier; 14. The first inner planetary gear set; 15. The first outer planetary gear set; 2. The second planet row; 21, the second sun gear; 22, the second ring gear; 23, the second planet carrier; 24, the second planetary gear set; 3, the third planet row; 31, the third sun gear; 32, The third ring gear; 33, the third planet carrier; 34, the third planetary gear set; 4, the box; 5, the input member; 6, the output member; C1, the first clutch; C2, the second clutch; C3, the second clutch Three clutches; B1, the first brake; B2, the second brake.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

As shown in Figure 1, a three-planetary automatic transmission according to an embodiment of the present invention is schematically shown, which includes an input member 5 (input shaft) and an output member 6 (output shaft), and the first one arranged in sequence along the same rotary shaft A planetary row 1, a second planetary row 2 and a third planetary row 3, a first clutch C1, a second clutch C2, a third clutch C3, a first brake B1, and a second brake B2;

Wherein, the first planetary row 1 includes a first sun gear 11, a first ring gear 12, a first planet carrier 13, a first inner planetary gear set 14 and a first outer planetary gear set 15 meshing with each other, and the connection relationship of these components It is: the first sun gear 11 is externally meshed with the first inner planetary gear set 14, the first inner planetary gear set 14 is externally meshed with the first outer planetary gear set 15, and the first outer planetary gear set is internally meshed with the first ring gear 12 , the first inner planetary wheel set 14 and the first outer planetary wheel set 15 are installed on the pin shafts at the corresponding positions of the first planetary carrier 13 through bearings;

The second planetary row 2 includes a second sun gear 21, a second ring gear 22, a second planet carrier 23, and a second planetary gear set 24. The connection relationship of these components is: the second planetary gear set 24 and the second sun gear 21 External meshing, the second planetary gear set 24 is internally meshed with the second ring gear 22, and the second planetary gear set 24 is installed on the pin shaft of the second planetary carrier 23 through a bearing;

The third planetary row 3 includes a third sun gear 31, a third ring gear 32, a third planet carrier 33 and a third planetary gear set 34. The connection relationship of these components is: the third planetary gear set 34 and the third sun gear 31 External meshing, the third planetary gear set 34 is internally meshing with the third ring gear 32, and the third planetary gear set 34 is installed on the pin shaft of the third planet carrier 33 through bearings.

Please continue to refer to Fig. 1, the first sun gear 11 is fixed, that is to say the first sun gear 11 is in the state of constant braking, therefore, the first sun gear 11 can be fixedly connected with the casing 4, so as to Avoid setting brakes at positions where it is unnecessary to set brakes, so as to reduce the number of brakes as much as possible;

The first ring gear 12 is connected to the output member 6 through the first clutch C1. The first planet carrier 13 and the second planet carrier 23 are fixedly connected by welding, integral manufacturing or spline connection. The second ring gear 22 and the third The planet carrier 33 is fixedly connected by means of welding, integral manufacturing or spline connection, etc., the input member 5 and the second sun gear 21 are fixedly connected by welding, integral manufacturing or by spline connection, etc., and the input member 5 is connected through the third clutch C3 Connect with the third sun gear 31;

The second clutch C2 is arranged between the second ring gear 22 and the second sun gear 21, the second ring gear 22 is connected with the second sun gear 21 through the second clutch C2, the function of the second clutch C2 is, when it selectively When the ground is closed, the second planetary row 2 and the input member 5 are rotated as a whole;

One end of the first brake B1 is connected to the case 4 of the transmission, and the other end is connected to the third planetary carrier 33. Its function is to brake the third planetary carrier 33 when the first brake B1 is selectively closed; One end of the second brake B2 is connected with the case 4 of the transmission, and the other end is connected with the third sun 31. Its effect is that when the second brake B2 is selectively closed, the third sun 31 can be wheel braked.

In addition, the above-mentioned three clutches can be multi-disc wet clutches or dog-tooth clutches, which facilitates the nesting design of clutches.

How the three-planetary automatic transmission according to the embodiment of the present invention realizes that two of the five operating elements are selectively closed can produce multiple speed ratio conversions between the input member 5 and the output member 6 below. of:

As shown in Table 1, it is the speed ratio conversion logic table of the three-planetary automatic transmission of the embodiment of the present invention. Table 1 lists which two operating elements are selectively closed, so that the input member 5 and the output member Between 6, six forward speed ratios and one reverse speed ratio are produced. For the convenience of expression, these six forward speed ratios are named as the first forward speed ratio to the sixth forward speed ratio, and these are listed in Table 1. The six forward speed ratios are marked as 1st gear to 6th gear in turn, and the reverse speed ratio is marked as R gear; in Table 1, K1, K2, and K3 are the characteristic parameters of the three planetary rows, and their specific values are the respective ring gears The ratio of the number of teeth to the number of teeth of the sun gear.

Please combine Table 1 and accompanying drawing 3 to show that when the first clutch C1 and the first brake B1 are closed simultaneously, the first forward speed ratio (first gear) can be generated between the input member 5 and the output member 6, and in the first gear , the first clutch C1 is closed to connect the first ring gear 12 with the output member 6, and the first brake B1 is closed so that the second ring gear 22 and the third planet carrier 33 are braked at the same time. Therefore, as shown in FIG. 3 As shown by the line, the power transmission route of the 1st gear is: the power is input from the input member 5 to the second sun gear 21, and then transmitted to the second planet carrier 23 by the second planetary gear set 24, and then transmitted to the second planet carrier 23 through the second planet carrier 23. The first planet carrier 13 is then transmitted to the first ring gear 12 by the first inner planetary gear set 14 and the first outer planetary gear set 15, and finally transmitted to the output member 6 by the first clutch C1 to output power; therefore, the first gear The transmission speed ratio is: i1=[K1×(1+K2)]/(K1-1).

As shown in Table 1 and accompanying drawing 4, when the first clutch C1 and the second brake B2 are closed at the same time, a second forward speed ratio (second gear) can be generated between the input member 5 and the output member 6, in the second gear , the first clutch C1 is closed to connect the first ring gear 12 with the output member 6, and the second brake B2 is closed so that the third sun gear 31 is braked. Therefore, as shown by the solid line in Figure 4, the power of the second gear There are two transmission routes: ①The power is input from the input member 5 to the second sun gear 21, and then transmitted to the second planetary carrier 23 by the second planetary gear set 24, and then transmitted to the first planetary carrier through the second planetary carrier 23 13, then the first inner planetary gear set 14 and the first outer planetary gear set 15 are transmitted to the first ring gear 12, and finally the first clutch C1 is transmitted to the output member 6 to output power; ②The power is input from the input member 5 to The second sun gear 21 is transmitted to the second ring gear 22 and the third planet carrier 33 by the second planetary gear set 24, and then transmitted to the third ring gear 32 by the third planetary gear set 34, and finally transmitted by the third ring gear 32 to the output member 6 to output the power; therefore, the transmission ratio of the 2nd gear is:

i2=[K1*(1+K2+K3)+K2*K3]/[(K1-1)*(1+K3)].

As shown in Table 1 and accompanying drawing 5, when the first clutch C1 and the third clutch C3 are simultaneously closed, a third forward speed ratio (3rd gear) can be generated between the input member 5 and the output member 6, in the 3rd gear , the first clutch C1 is closed to connect the first ring gear 12 to the output member 6, and the third clutch C3 is closed to connect the third sun gear 31 as an input element to the input member 5. Therefore, as shown by the solid line in FIG. 5 As shown, three power transmission routes are generated under the 3rd gear. ①The power is input from the input member 5 to the second sun gear 21, and is transmitted to the second planetary carrier 23 by the second planetary gear set 24, and then passes through the second planetary carrier. 23 is transmitted to the first planet carrier 13, then transmitted to the first ring gear 12 by the first inner planetary gear set 14 and the first outer planetary gear set 15, and finally transmitted to the output member 6 by the first clutch C1 to output power; ② The power is input to the second sun gear 21 by the input member 5, and then transmitted to the second ring gear 22 and the third planet carrier 33 by the second planetary gear set 24, and then transmitted to the third ring gear 32 by the third planetary gear set 34 , and finally the power is output from the third ring gear 32 to the output member 6; ③The power is input from the input member 5, transmitted to the third sun gear 31 through the third clutch C3, and then transmitted to the third sun gear 31 by the third planetary gear set 34. The ring gear 32 is finally transmitted to the output member 6 by the third ring gear 32 to output power; therefore, the transmission speed ratio of the third gear is:

i3=[K1*(1+K2+K3)+K2*K3]/[(K1-1)*(1+K2+K3)].

As shown in Table 1 and accompanying drawing 6, when the first clutch C1 and the second clutch C2 are closed at the same time, the fourth forward speed ratio (4th gear) can be generated between the input member 5 and the output member 6, in the 4th gear , the first clutch C1 is closed to connect the first ring gear 12 to the output member 6, and the second clutch C2 is closed to connect the second ring gear 22 to the input member 5. At this time, the second planetary row 2 and the input member rotate integrally Power input, therefore, as shown by the solid line in Figure 6, the power transmission route of the 4th gear is: the power is input by the input member 5, and the power is transmitted to the first planet carrier 13 through the overall rotation of the second planetary row 2, and then the power is transmitted by the second planetary row 2. An inner planetary gear set 14 and a first outer planetary gear set 15 are transmitted to the first ring gear 12, and finally the first clutch C1 is transmitted to the output member 6 to output power; therefore, the transmission speed ratio of the 4th gear is: i4=K1 /(K1-1)

As shown in Table 1 and accompanying drawing 7, when the second clutch C2 and the third clutch C3 are simultaneously closed, the sixth forward speed ratio (5th gear) can be generated between the input member 5 and the output member 6, in the 5th gear Among them, the second clutch C2 and the third clutch C3 are closed at the same time so that the second planetary row 2 and the third planetary row 3 and the input member rotate synchronously as a whole to input power, and then the output member 6 outputs the power. Therefore, the 5th gear It is a direct gear, and its transmission speed ratio i5=1.

As shown in Table 1 and accompanying drawing 8, when the second clutch C2 and the second brake B2 are simultaneously closed, the sixth forward speed ratio (6th gear) can be generated between the input member 5 and the output member 6, in the 6th gear , the second clutch C2 is closed so that the second ring gear 22 is connected to the input member 5, at this time, the second planetary row 2 and the input member rotate integrally to input power, and the second brake B2 is closed to brake the third sun gear. Therefore, As shown by the solid line in Figure 8, the power transmission route of the 6th gear is: the power is input from the input member 5 to the second planetary row 2, and the second planetary row 2 rotates as a whole to transmit the power to the third planetary carrier 33, and then through The third planetary gear set 34 transmits to the third ring gear 32 , and finally the third ring gear 32 transmits the power to the output member 6 to output the power. Therefore, the transmission speed ratio of the 6th gear is: i6=K3/(1+K3).

As shown in Table 1 and accompanying drawing 9, when the first brake B1 and the third clutch C3 are closed at the same time, a reverse speed ratio (R gear) can be generated between the input member 5 and the output member 6. In the R gear, The first brake B1 is closed so that the second ring gear 22 and the third planet carrier 33 are braked simultaneously, and the third clutch C3 is closed so that the third sun gear 31 is connected to the input member 5. Therefore, as shown by the solid line in FIG. 9 , The power transmission route of the R gear is: the power is input by the input member 5, transmitted to the third sun gear 31 through the third clutch C3, and then transmitted to the third ring gear 32 through the third planetary gear set 34, and finally transmitted by the third The ring gear 32 transmits the power to the output member 6 to output the power, therefore, the transmission speed ratio of the R gear: iR=-K3.

Table I

Example 2

As shown in Figure 2, the three-planetary automatic transmission in this embodiment is substantially the same as that in Embodiment 1, except that the second clutch C2 is located in a different position. The second clutch C2 in this embodiment is connected between the second planetary carrier 23 and the Between the second sun gear 21, that is, the second planet carrier 23 is connected to the second sun gear 21 through the second clutch C2, however, the function of the second clutch C2 here is the same as that of the second clutch C2 in Embodiment 1 Similarly, when it is selectively closed, the second planetary row is turned as a whole; therefore, the three-planetary automatic transmission of the present embodiment shares a speed ratio conversion logic table (Table 1) with Embodiment 1, and each of the two The power transmission route diagram under the gears is also the same, that is, the functions realized by the three-planetary automatic transmission in this embodiment are consistent with the functions realized in Embodiment 1.

In order to solve the same problem, an embodiment of the present invention also provides a vehicle, including the three-planetary automatic transmission of any one of the above embodiments.

To sum up, the three-planetary automatic transmission of the present invention adopts three clutches and two brakes as the connection scheme of operating elements combined with three planetary rows, and can realize the selectivity of using only two of the operating elements. A variety of combinations of ground closures can produce multiple (six forward speed ratios and one reverse speed ratio) speed ratio conversions; and relatively few (two) brakes are used as operating elements, which can greatly reduce the processing of the box It is difficult to manufacture, and it is conducive to the lightweight design and manufacture of the box under the condition of ensuring the strength of the box; in addition, the use of more clutches can facilitate the nesting design of the clutches, making the structure of the transmission more compact, and can be beneficial in Cut off the connection relationship between the planetary rows in a specific gear, so that the redundant planetary row idles without carrying torque or does not participate in the rotation, so as to reduce the drag torque of the planetary row and improve the transmission efficiency of the transmission.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (10)

1. A three-planetary automatic transmission, characterized in that it comprises an input member and an output member, the first, second and third planetary rows arranged in sequence along the same rotary shaft, the first, second and third clutches and The first and second brakes, wherein the first planetary row includes a first ring gear, a first inner planetary gear set and a first outer planetary gear set meshing with each other, a first sun gear and a first planetary carrier; The second planetary row includes the second ring gear, the second planetary gear set, the second sun gear and the second planet carrier; the third planetary row includes the third ring gear, the third planetary gear set, the third sun gear and the second planetary carrier. Triple planet carrier; The first sun gear is fixed, the first ring gear is connected to the output member through the first clutch, the first planet carrier is fixedly connected to the second planet carrier, and the second gear ring is fixedly connected with the third planet carrier, the input member is fixedly connected with the second sun gear, the input member is connected with the third sun gear through the third clutch, and the second clutch sets on the second planetary row, the second clutch is selectively closed such that the second planetary row unitarily rotates with the input member; The first brake is selectively closed to brake the third planet carrier, and the second brake is selectively closed to brake the third sun gear. 2. The three-planetary automatic transmission according to claim 1, wherein the second clutch is arranged between the second ring gear and the second sun gear, and the second ring gear passes through the second sun gear. The second clutch is connected with the second sun gear. 3. The three-planetary automatic transmission according to claim 1, wherein the second clutch is arranged between the second planetary carrier and the second sun gear, and the second planetary carrier passes through the first The second clutch is connected with the second sun gear. 4. The three-planetary automatic transmission according to claim 1, characterized in that, the first sun gear is fixedly connected to the case of the transmission. 5. The three-planetary automatic transmission according to claim 1, characterized in that, in the first planetary row, the first sun gear is externally meshed with the first inner planetary gear set, and the first The inner planetary gear set is externally meshed with the first outer planetary gear set, the first outer planetary gear set is internally meshed with the first ring gear, and both the first inner planetary gear set and the first outer planetary gear set pass through bearings Installed on the pin shaft at the corresponding position of the first planet carrier. 6. The three-planetary automatic transmission according to claim 1, characterized in that, in the second planetary row, the second sun gear and the second planetary gear set are externally meshed, and the second planetary gear set is meshed with the second ring gear meshing, the second planetary gear set is mounted on the pin shaft of the second planetary carrier through bearings; in the third planetary row, the third sun gear and the third planetary gear set are externally meshed, and the third planetary gear set and the third ring gear Inner meshing, the third planetary wheel set is installed on the pin shaft of the third planetary carrier through bearings. 7. The three-planetary automatic transmission according to claim 1, characterized in that, one end of the first brake is connected to the case of the transmission, and the other end is connected to the third planetary carrier; One end is connected with the case of the transmission, and the other end is connected with the third sun gear. 8. The three-planetary automatic transmission according to claim 1, wherein the first, second and third clutches are all multi-plate wet clutches or dog-tooth clutches. 9. The three-planetary automatic transmission according to claim 1, characterized in that, when the first clutch and the first brake are closed simultaneously, a first Forward speed ratio; a second forward speed ratio may be established between the input member and the output member when the first clutch and the second brake are simultaneously engaged; a third forward speed ratio may be established between the input member and the output member when the first clutch and the third clutch are simultaneously closed; a fourth forward speed ratio may be established between the input member and the output member when the first clutch and the second clutch are simultaneously closed; a fifth forward speed ratio may be established between said input member and output member when said second clutch is simultaneously closed with said third clutch; a sixth forward speed ratio may be established between the input member and the output member when the second brake is simultaneously engaged with the second clutch; A reverse speed ratio may be created between the input member and the output member when the first brake and the third clutch are simultaneously closed. 10. A vehicle, characterized by comprising the three-planetary automatic transmission according to any one of claims 1 to 9.