CN110953307B

CN110953307B - Eight-speed automatic transmission

Info

Publication number: CN110953307B
Application number: CN201911348718.9A
Authority: CN
Inventors: 冯浩成; 王凯峰; 严鉴铂; 刘义
Original assignee: Shaanxi Fast Gear Co Ltd
Current assignee: Shaanxi Fast Gear Co Ltd
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2021-01-12
Anticipated expiration: 2039-12-24
Also published as: CN110953307A

Abstract

The invention discloses an eight-speed automatic transmission, which comprises four planetary gear sets, two clutches and four brakes, wherein the four planetary gear sets are connected with the four clutches through the four clutches; after being fixedly connected, the first sun gear and the fourth sun gear are integrally and selectively connected to a fixed end through a first brake or selectively connected to an input end through a second clutch; the fourth planet carrier is selectively connected to the fixed end through a fourth brake; the fourth gear ring, the first planet carrier and the second gear ring are fixedly connected and then are selectively connected to the fixed end through a second brake; the first gear ring, the third planet carrier and the output end are fixedly connected; the second sun gear is fixedly connected with the input end; the second planet carrier is fixedly connected with the third gear ring; the third sun gear is selectively connected to the fixed end through a third brake; through in two planet row are connected, adopt and link to each other sun gear and planet carrier or planet carrier and ring gear, effectively avoided unnecessary inertia's production, reduced shift control's the degree of difficulty, reduced the processing cost.

Description

Eight-speed automatic transmission

Technical Field

The invention belongs to the technical field of transmissions, and particularly relates to an eight-speed automatic transmission.

Background

With the improvement of living standard of people, the transmission of the automobile is gradually switched from a manual transmission to an automatic transmission; among automatic transmissions, a hydraulic automatic transmission is an important branch thereof. The gears of the hydraulic automatic transmission are gradually increased from two early forward gears to six, eight or nine currently popular forward gears; the more gears of the hydraulic automatic transmission, the more flexible the gear shifting of the hydraulic automatic transmission can be, and a driver can have better driving experience. Therefore, the trend of the gears of the hydraulic automatic transmission is always to develop the gears with more gears. The gear of the hydraulic automatic transmission mainly applied to the current market is mostly 6 gears, the hydraulic automatic transmission with 8 gears is mainly applied to the vehicle type of the middle and high end, and the popularization rate is the trend of increasing year by year.

At present, in the existing eight-speed automatic transmission, the sun gear is directly connected with the gear ring, and because the span of the connection between the sun gear and the gear ring is large, the connected part needs large processing cost, and the connected part has redundant rotational inertia, so that the difficulty of gear shifting control is increased.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides an eight-speed automatic transmission.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides an eight-speed automatic transmission, which comprises a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first clutch, a second clutch, a first brake, a second brake, a third brake and a fourth brake, wherein the first brake is connected with the first planetary gear set;

the first planetary gear set comprises a first sun gear, a first planet carrier, a first gear ring and a first planet gear; the second planetary gear set comprises a second sun gear, a second planet carrier, a second gear ring and a second planet gear; the third planetary gear set comprises a third sun gear, a third planet carrier, a third gear ring and a third planet gear; the fourth planetary gear set comprises a fourth sun gear, a fourth planet carrier, a fourth gear ring and a fourth planet gear;

after being fixedly connected, the first sun gear and the fourth sun gear are integrally and selectively connected to a fixed end through a first brake or selectively connected to an input end through a second clutch;

the fourth planet carrier is selectively connected to the fixed end through a fourth brake;

the fourth gear ring, the first planet carrier and the second gear ring are fixedly connected and then are selectively connected to the fixed end through a second brake or selectively connected to the input end through a first clutch;

the first gear ring, the third planet carrier and the output end are fixedly connected;

the second sun gear is fixedly connected with the input end; the second planet carrier is fixedly connected with the third gear ring;

the third sun gear is selectively connected to the fixed end by a third brake.

Furthermore, the input end and the output end are arranged on the same side or different sides of the transmission.

Furthermore, the input end is directly connected with the output end of the engine; or connected with the output end of the engine through a hydraulic torque converter.

Furthermore, the number of the first planet wheels, the second planet wheels, the third planet wheels and the fourth planet wheels is respectively more than or equal to 3.

Furthermore, when the input end and the output end are arranged on the same side, the input end is provided with a differential mechanism.

Further, the first planetary gear set, the second planetary gear set, the third planetary gear set and the fourth planetary gear set are single-stage planetary rows.

Further, the first sun gear and the fourth sun gear are connected by a spline or welding.

Furthermore, the fourth gear ring, the first planet carrier and the second gear ring are connected by a spline or welding.

Furthermore, the first gear ring, the third planet carrier and the output end are connected by a spline or welding.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides an eight-speed automatic transmission, wherein a sun gear is connected with a planet carrier or the planet carrier is connected with a gear ring in the connection of two planet rows, so that the generation of redundant rotational inertia is effectively avoided, and the difficulty of gear shifting control is reduced; meanwhile, the connecting span of the sun gear and the gear ring is reduced, and the processing cost is reduced.

The input end and the output end of the speed changer are arranged on the same side or different sides of the speed changer, so that the transverse arrangement or the longitudinal arrangement of the speed changer is realized; when the transverse mode is adopted, the transmission has a compact structure and can be used on a car; when the longitudinal arrangement mode is adopted, the torque is large, and vehicle types such as pickup trucks are met.

According to the eight-speed automatic transmission, two shifting elements are required to be combined during transmission of a specific gear, and shifting can be realized only by disconnecting one shifting element and then connecting the other shifting element during continuous shifting, so that shifting impact is effectively reduced; and the shifting device has good gear jumping performance, and can only disconnect one shifting element and then connect another shifting element when the specific gears are shifted in a cross gear mode, so that the shifting impact is reduced.

Drawings

Fig. 1 is a schematic connection structure of an eight-speed automatic transmission according to embodiment 1 of the invention;

fig. 2 is a schematic connection structure diagram of an eight-speed automatic transmission according to embodiment 2 of the invention;

fig. 3 is a lever principle structural schematic diagram of an eight-speed automatic transmission according to embodiment 1 or embodiment 2 of the invention;

fig. 4 is a schematic diagram showing a result of lever principle analysis of an eight-speed automatic transmission according to embodiment 1 or embodiment 2 of the present invention;

FIG. 5 is a chart of the logic of operation of the driveline torque transmitting devices for each gear of the eight speed automatic transmission of the present invention.

Wherein, 1 input end, 2 output end, 3 fixed end; PG1 first planetary gear set, PG2 second planetary gear set, PG3 third planetary gear set, PG4 fourth planetary gear set, C1 first clutch, C2 second clutch, B1 first brake, B2 second brake, B3 third brake, B4 fourth brake; s1 first sun gear, S2 second sun gear, S3 third sun gear, S4 fourth sun gear, PC1 first carrier, PC2 second carrier, PC3 third carrier, PC4 fourth carrier, a1 first ring gear, a2 second ring gear, A3 third ring gear, a4 fourth ring gear, P1 first planet gear, P2 second planet gear, P3 third planet gear, P4 fourth planet gear.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments; the following specific embodiments are provided to illustrate the present invention, but are not intended to limit the scope of the present invention.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Example 1

As shown in fig. 1, the present invention provides an eight-speed automatic transmission including a first planetary gear set PG1, a second planetary gear set PG2, a third planetary gear set PG3, a fourth planetary gear set PG4, a first clutch C1, a second clutch C2, a first brake B1, a second brake B2, a third brake B3, and a fourth brake B4;

the first planetary gear set PG1 adopts a single-stage planetary row and comprises a first sun gear S1, a first planet carrier PC1, a first ring gear a1 and a first planet gear P1; the second planetary gear set adopts a single-stage planetary row and comprises a second sun gear S2, a second planet carrier PC2, a second ring gear A2 and a second planet gear P2; the third planetary gear set adopts a single-stage planetary row and comprises a third sun gear S3, a third planet carrier PC3, a third ring gear A3 and a third planet gear P3; the fourth planetary gear set adopts a single-stage planet row and comprises a fourth sun gear S4, a fourth planet carrier PC4, a fourth gear ring A4 and a fourth planet gear P4;

the first sun gear S1 is fixedly connected with the fourth sun gear S4, and then is selectively connected to the fixed end 3 through the first brake B1 or to the input end 1 through the second clutch C2;

the fourth planet carrier PC4 is selectively connected to the fixed end 3 through a fourth brake B4;

the fourth ring gear A4, the first planet carrier PC1 and the second ring gear A2 are fixedly connected and then are selectively connected to the fixed end 3 through a second brake B2 or to the input end 1 through a first clutch C1;

the first gear ring A1, the third planet carrier PC3 and the output end 2 are fixedly connected;

the second sun gear S2 is fixedly connected with the input end 1 and is used for directly receiving the power transmitted by the input end 1; the second planet carrier PC2 is fixedly connected with the third ring gear A3;

the third sun gear S3 is selectively connected to the fixed end 3 by a third brake B3.

The input end 1 and the output end are arranged on the same side of the transmission, and the input end 1 is directly connected with the output end of the engine or is connected with the output end of the engine through a hydraulic torque converter or other power transmission elements; the output end 2 adopts a belt differential mechanism.

The numbers of the first planet gears P1, the second planet gears P2, the third planet gears P3 and the fourth planet gears P4 are respectively more than or equal to 3.

Example 2

As shown in fig. 2, embodiment 2 is identical in structural principle to the eight-speed automatic transmission described in embodiment 1, except that the input 1 and the output 2 are provided on both sides of the transmission, respectively.

According to the eight-speed automatic transmission, the sun gear is connected with the planet carrier or the planet carrier is connected with the gear ring in the connection of the two planet rows, so that the generation of redundant rotational inertia is effectively avoided, and the difficulty in gear shifting control is reduced; meanwhile, the connecting span of the sun gear and the gear ring is reduced, and the processing cost is reduced.

The automatic hydraulic transmission needs to combine two shifting elements when a specific gear is used for transmission, and shifting can be realized only by disconnecting one shifting element and then connecting another shifting element when continuous shifting is performed, so that shifting impact can be reduced to a certain extent. And the shifting device has good gear jumping performance, and can only disconnect one shifting element and then connect another shifting element when the specific gears are shifted in a cross gear mode, so that the shifting impact is reduced.

The transmission can be designed in a transverse or longitudinal mode, and the power of the input end can be directly transmitted to the input end from the engine or the engine through the torque converter; when the transverse mode is adopted, the transmission has a compact structure and can be used on a car; when the longitudinal arrangement mode is adopted, the torque is large, and vehicle types such as pickup trucks are met.

FIG. 3 is a schematic lever diagram of an eight-speed automatic transmission according to the present invention, which is a simplified representation of FIGS. 1-2, and FIG. 3 shows the connection method between the planetary gear sets, which can be used for power transmission analysis; when the input rotating speed is input at the input end, the rotating speeds of the parts under different gears can be obtained through the constraint relation of the parts and the speed ratio relation of the planet row.

As shown in fig. 4, fig. 4 is a diagram of the lever principle analysis result; the two horizontal lines in the lever principle analysis result chart of fig. 4 are represented as: the horizontal line of "0" represents that the speed is zero, and "1" represents that the speed is the input rotating speed and the rotating speed is the same as the input end 1; the characters on the horizontal line refer to the names in the description of the figures, the spacing of which is determined by the number of teeth between the members and the matching relationship between them, and the straight lines between the members represent the corresponding connecting elements fixedly connected thereto, which is a speed comparison method commonly used by those skilled in the art.

The clutch is at the corresponding insertion position of the horizontal line with the input of 1, and the brake is at the corresponding insertion position of the fixed horizontal line 0; the value of the speed transfer line that will pass through the active brake or clutch, and ultimately the intersection of the speed transfer line with the OUTPUT line of fig. 5 to horizontal line "0", is the ratio of the OUTPUT speed to the input speed for the operating condition of the torque-transmitting mechanism set.

As shown in the attached figure 5, the eight-speed automatic transmission can realize eight forward gears and two reverse gears, and the specific operation logic is as follows: wherein the gear logic table of fig. 5 gives the ratio of the speed of the transmission ratio input 1 to the speed of the output 2 of the transmission in different gears when the ratios of the number of teeth of the gear ratio ring gear to the number of teeth of the sun gear of the first planetary row PG1, the second planetary row PG2, the third planetary row PG3 and the fourth planetary row PG4 are 2.94, 2.17, 2.25 and 2.03, respectively; the derailleur has eight and advances to keep off with two reverse gears, compares in using comparatively extensive six fender hydraulic automatic transmission, has increased two and has advanced the fender and a reverse gear, can provide more comfortable driving experience for the customer.

The specific gear transmission route is as follows:

1, gear 1: the second brake B2 and the third brake B3 act, power is input into the second sun gear S2 from the input end, and the power is coupled by the power of the second planetary row and the power of the third planetary row and then is transmitted to the output end;

and 2, gear: the third brake B3 and the fourth brake B4 act, power is input to the second sun gear S2 from the input end, and the power is coupled by the power of the four planetary rows and then is transmitted to the output end;

and 3, gear shifting: the first brake B1 and the third brake B3 are in action, power is input into the second sun gear S2 from the input end, and the power is coupled by the power of the second, third and fourth planet rows and then is transmitted to the output end;

4, gear shifting: the first clutch C1 and the third brake B3 are in action, power is input into the second sun gear S2 and the first sun gear S1 from the input end, and the power is transmitted to the output end after being coupled by the power of the second, third and fourth planet rows;

and 5, gear shifting: the second clutch C2 and the third brake B3 are in action, power is input into the second ring gear A2 and the second sun gear S2 from the input end, and the power is coupled by the power of the third planetary row and the power of the fourth planetary row and then is transmitted to the output end;

6, gear 6: the first clutch C1 and the second clutch C2 act, power is input into the first planet carrier PC1 and the first sun gear S1 from the input end, and the power is transmitted to the output end after being coupled by the power of the second planet row and the power of the fourth planet row;

and 7, gear shifting: the second clutch C2 and the first brake B1 act, power is input into the first planet carrier PC1 from the input end, and the power is transmitted to the output end after being coupled by the power of the second planet row and the fourth planet row;

and 8, gear shifting: the second clutch C2 and the fourth brake B4 are activated, power is input into the first planet carrier PC1 from the input end, and the power is coupled by the power of the first, second and fourth planet rows and then is transmitted to the output end;

r1 gear: the first clutch C1 and the second brake B2 are in action, power is input into the first sun gear S1 from the input end, and the power is transmitted to the output end after being coupled by the power of the second planet row and the power of the fourth planet row;

r2 gear: the first clutch C1 and the fourth brake B4 are activated, and power is input from the input end to the first sun gear S1 and the fourth sun gear S4, and is coupled by the power of the first, second and fourth planetary rows and then transmitted to the output end.

The transmission according to the invention, when performing power transmission in a specific gear, only needs to engage two shifting elements each time, and when the gear of the transmission is continuously shifted from a low gear to a high gear, only needs to disengage one shifting element and engage another shifting element each time, the shifting logic according to the invention can greatly reduce shifting shocks compared to the situation in which two gears are disengaged and two other gears are engaged.

The transmission of the invention has better gear jumping performance, and according to the shifting logic table of fig. 5, the transmission can achieve the purpose of gear jumping with less shifting impact by only disconnecting one shifting element and combining another shifting element during gear jumping under the following five conditions:

jumping from any one of the first gear to the fifth gear to any other one of the first gear to the fifth gear;

jumping from any one of fifth gear to eighth gear to any other one of fifth gear to eighth gear;

from the second gear to the eighth gear;

from third to seventh gear;

from fourth to sixth gear.

The above description is only illustrative of the preferred embodiments of the present invention, and any structural changes, improvements, modifications, etc. made without departing from the principle of the present invention are deemed to be within the scope of the present invention.

Claims

1. An eight-speed automatic transmission characterized by comprising a first planetary gear set (PG1), a second planetary gear set (PG2), a third planetary gear set (PG3), a fourth planetary gear set (PG4), a first clutch (C1), a second clutch (C2), a first brake (B1), a second brake (B2), a third brake (B3), and a fourth brake (B4);

the first planetary gear set (PG1) includes a first sun gear (S1), a first carrier (PC1), a first ring gear (a1), and a first planet gear (P1); the second planetary gear set includes a second sun gear (S2), a second planet carrier (PC2), a second ring gear (a2), and second planet gears (P2); the third planetary gear set includes a third sun gear (S3), a third planet carrier (PC3), a third ring gear (A3), and a third planet gear (P3); the fourth planetary gear set comprises a fourth sun gear (S4), a fourth planet carrier (PC4), a fourth ring gear (A4) and a fourth planet gear (P4);

the first sun gear (S1) and the fourth sun gear (S4) are fixedly connected and then are selectively connected to the fixed end (3) through a first brake (B1) or selectively connected to the input end (1) through a second clutch (C2);

the fourth planet carrier (PC4) is selectively connected to the fixed end (3) through a fourth brake (B4);

after the fourth gear ring (A4), the first planet carrier (PC1) and the second gear ring (A2) are fixedly connected, the whole is selectively connected to the fixed end (3) through a second brake (B2) or selectively connected to the input end (1) through a first clutch (C1);

the first gear ring (A1), the third planet carrier (PC3) and the output end (2) are fixedly connected;

the second sun gear (S2) is fixedly connected with the input end (1); the second planet carrier (PC2) is fixedly connected with the third ring gear (A3);

the third sun gear (S3) is selectively connected to the fixed end (3) by a third brake (B3).

2. An eight-speed automatic transmission according to claim 1, characterized in that the input (1) and the output (2) are arranged on the same or different sides of the transmission.

3. An eight speed automatic transmission according to claim 1, wherein the input (1) is directly connected to the output of the engine; or connected with the output end of the engine through a hydraulic torque converter.

4. An eight-speed automatic transmission according to claim 1, wherein the number of first planets (P1), second planets (P2), third planets (P3) and fourth planets (P4) is equal to or greater than 3, respectively.

5. An eight speed automatic transmission according to claim 2, characterized in that the input (2) is provided with a differential when the input (1) is provided on the same side as the output (2).

6. An eight speed automatic transmission according to claim 1, characterized in that the first planetary gear set (PG1), the second planetary gear set (PG2), the third planetary gear set (PG3) and the fourth planetary gear set (PG4) are a single planetary row.

7. An eight speed automatic transmission according to claim 1, wherein the first sun gear (S1) and the fourth sun gear (S4) are splined or welded.

8. An eight speed automatic transmission according to claim 1, wherein the fourth ring gear (a4), the first planet carrier (PC1) and the second ring gear (a2) are splined or welded.

9. An eight speed automatic transmission according to claim 1, wherein the first ring gear (a1), the third planet carrier (PC3) and the output (2) are splined or welded.