Planetary gear train of automatic transmission for vehicle

This application claims priority to and the benefit of Korean Patent Application No. 10-2017-0006059, filed on Jan. 13, 2017, the entire contents of which are incorporated herein by reference.

The present disclosure relates to an automatic transmission for a vehicle that improves power delivery performance and fuel economy.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Generally, an automatic transmission achieving more speed stages has been developed to enhance fuel efficiency and drivability.

Such an automatic transmission with more speed stages is desired to improve power performance and driving efficiency while pursuing the engine-downsizing. Particularly, highly efficient multiple-speeds transmissions are desired to have excellent linearity of step ratios which is closely related to drivability such as acceleration before and after shift and rhythmical engine speed. These features are considered to secure competitiveness in automatic transmission field.

However, in the automatic transmission, as the number of speed stages increase, the number of internal components increase, and as a result, mountability, cost, weight, transmission efficiency, and the like may still deteriorate.

Accordingly, development of a planetary gear train which may have a small number of components may be important in order to increase a fuel efficiency.

A conventional eight-speed automatic transmission has gear ratio span of 6.5-7.5 (gear ratio span is an important factor for securing linearity of step ratios), and thus improvement of power performance and fuel economy may not be great.

In addition, if an eight-speed automatic transmission has gear ratio span greater than 9.0, it is hard to secure linearity of step ratios. Therefore, driving efficiency of an engine and drivability of a vehicle may be deteriorated.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

The present disclosure provides a planetary gear train of an automatic transmission for a vehicle having advantages of improving power delivery performance and fuel efficiency through ten forward speed stages and one reverse speed stage and reducing drag loss of clutches and brakes using five planetary gear sets and six engaging elements.

Another form of the present disclosure provides a planetary gear train of an automatic transmission for a vehicle having further advantages of improving torque delivery efficiency and durability by using a planetary gear set in torque parallel type and reducing torque share of each planetary gear set and each engaging element.

Moreover the present disclosure provides a high-efficiency planetary gear train of an automatic transmission for a vehicle having further advantages of increasing flexibility of output gear ratios and improving linearity of step ratios by using five planetary gear sets for achieving ten forward speed stages and one reverse speed stage.

A planetary gear train of an automatic transmission for a vehicle according to one exemplary form of the present disclosure may include: an input shaft receiving torque from an engine; an output shaft outputting torque; a first planetary gear set including first, second, and third rotation elements; a second planetary gear set including fourth, fifth, and sixth rotation elements; a third planetary gear set including seventh, eighth, and ninth rotation elements; a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements; a fifth planetary gear set including thirteenth, fourteenth, and fifteenth rotation elements; a first shaft connected to the first rotation element and the input shaft; a second shaft connected to the fourteenth rotation element and the output shaft; a third shaft connected to the sixth rotation element and the thirteenth rotation element; a fourth shaft connected to the eleventh rotation element and the fifteenth rotation element; a fifth shaft connected to the fifth rotation element and the eighth rotation element; a sixth shaft connected to the ninth rotation element; a seventh shaft connected to the third rotation element, the seventh rotation element, and the tenth rotation element; an eighth shaft connected to the second rotation element and the fourth rotation element; and a ninth shaft connected to the twelfth rotation element.

In addition, the planetary gear train may further include six engaging elements selectively connecting any one shaft of the nine shafts to another shaft or to a transmission housing, wherein each of forward speeds or a reverse speed is achieved by operating three engaging elements among the six engaging elements.

In addition, the six engaging elements may include three clutches and three brakes, and each of the three clutches is configured to connect two shafts each other among the nine shafts. Each of the three brakes is configured to selectively connect the transmission housing to another shaft of the nine shafts that is not connected with the input shaft or the output shaft.

In addition, the six engaging elements may include: a first clutch disposed between the sixth shaft and the second shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the first shaft and the third shaft; a first brake disposed between the eighth shaft and the transmission housing; a second brake disposed between the seventh shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing.

The six engaging elements may include: a first clutch disposed between the sixth shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the first shaft and the third shaft; a first brake disposed between the eighth shaft and the transmission housing; a second brake disposed between the seventh shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing.

In addition, the first, second, and third rotation elements may be a first sun gear, a first planet carrier, and a first ring gear respectively, the fourth, fifth, and sixth rotation elements may be a second sun gear, a second planet carrier, and a second ring gear respectively, the seventh, eighth, and ninth rotation elements may be a third sun gear, a third planet carrier, and a third ring gear respectively, the tenth, eleventh, and twelfth rotation elements may be a fourth sun gear, a fourth planet carrier, and a fourth ring gear respectively, and the thirteenth, fourteenth, and fifteenth rotation elements may be a fifth sun gear, a fifth planet carrier, and a fifth ring gear respectively.

In addition, the first, second, third, fourth, and fifth planetary gear sets may be disposed in a sequence of the first, fourth, third, second, and fifth planetary gear sets from an engine side.

According to an exemplary form of the present disclosure, ten forward speed stages and one reverse speed stage may be achieved by combining five planetary gear sets being simple planetary gear sets with six engaging elements.

In addition, since gear ratio span greater than 8.5 is provided, driving efficiency of the engine may be increased. In addition, since linearity of step ratios can be provided for multiple speed stages, drivability such as acceleration before and after shift, rhythmical engine speed, and so on may be improved.

In addition, since ten forward speed stages and one reverse speed stages are achieved by using five planetary gear sets but the number of engaging elements is reduced, drag loss of clutches and brakes may be reduced and power delivery efficiency and fuel efficiency may be improved.

In addition, since a planetary gear set on an output side in torque parallel type is used and torque is evenly shared to each planetary gear set and each engaging element, and thus torque delivery efficiency and durability may be improved.

In addition, since five planetary gear sets are used to achieve ten forward speed stages and one reverse speed stage, flexibility of output gear ratios may be increased and linearity of step ratios may be improved.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a planetary gear train according to the first exemplary form of the present disclosure;

FIG. 2 is one example of an operation chart of control elements at each speed stage in the planetary gear train according to the first exemplary form of the present disclosure;

FIG. 3 is another example of an operation chart of control elements at each speed stage in the planetary gear train according to the first exemplary form of the present disclosure;

FIG. 4 is a schematic diagram of a planetary gear train according to the second exemplary form of the present disclosure;

FIG. 5 is one example of an operation chart of control elements at each speed stage in the planetary gear train according to the second exemplary form of the present disclosure; and

FIG. 6 is another example of an operation chart of control elements at each speed stage in the planetary gear train according to the second exemplary form of the present disclosure.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

Hereinafter, exemplary forms of the present disclosure will be described in detail with reference to the accompanying drawings.

However, parts which are not related with the description are omitted for clearly describing the exemplary forms of the present disclosure.

In the following description, dividing names of components into first, second, and the like is to divide the names because the names of the components are the same as each other and an order thereof is not particularly limited.

FIG. 1 is a schematic diagram of a planetary gear train according to the first exemplary form of the present disclosure.

Referring to FIG. 1 , a planetary gear train includes: first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 disposed on the same axis; an input shaft IS; and output shaft OS; nine shafts TM 1 to TM 9 connected to at least one rotation element of the first, second, third, fourth, and fifth planetary gear sets (i.e., PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 ); engaging elements including three clutches C 1 to C 3 and three brakes B 1 to B 3 ; and a transmission housing H.

Torque input from an engine to the input shaft IS is changed by cooperation of the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 , and the changed torque is output through the output shaft OS.

According to the first exemplary form of the present disclosure, the planetary gear sets are disposed in a sequence of the first, fourth, third, second, and fifth planetary gear sets PG 1 , PG 4 , PG 3 , PG 2 , and PG 5 from the engine.

The input shaft IS is an input member and torque from a crankshaft of the engine is torque-converted through a torque converter to be input into the input shaft IS.

The output shaft OS is an output member, is disposed on the same axis with the input shaft IS, and transmits driving torque to a driving wheel through a differential apparatus.

The first planetary gear set PG 1 is a single pinion planetary gear set and includes: a first sun gear S 1 being a first rotation element N 1 , a first planet carrier PC 1 being a second rotation element N 2 and rotatably supporting a first pinion gear P 1 engaged with the first sun gear S 1 of the first rotation element N 1 , and a first ring gear R 1 being a third rotation element N 3 and engaged with the first pinion gear P 1 .

The second planetary gear set PG 2 is a single pinion planetary gear set and includes: a second sun gear S 2 being a fourth rotation element N 4 , a second planet carrier PC 2 being a fifth rotation element N 5 and rotatably supporting a second pinion gear P 2 engaged with the second sun gear S 2 of the fourth rotation element N 4 , and a second ring gear R 2 being a sixth rotation element N 6 and engaged with the second pinion gear P 2 .

The third planetary gear set PG 3 is a single pinion planetary gear set and includes: a third sun gear S 3 being a seventh rotation element N 7 , a third planet carrier PC 3 being an eighth rotation element N 8 and rotatably supporting a third pinion gear P 3 engaged with the third sun gear S 3 of the seventh rotation element N 7 , and a third ring gear R 3 being a ninth rotation element N 9 and engaged with the third pinion gear P 3 .

The fourth planetary gear set PG 4 is a single pinion planetary gear set and includes: a fourth sun gear S 4 being a tenth rotation element N 10 , a fourth planet carrier PC 4 being an eleventh rotation element N 11 and rotatably supporting a fourth pinion gear P 4 engaged with the fourth sun gear S 4 of the tenth rotation element N 10 , and a fourth ring gear R 4 being a twelfth rotation element N 12 engaged with the fourth pinion gear P 4 .

The fifth planetary gear set PG 5 is a single pinion planetary gear set and includes: a fifth sun gear S 5 being a thirteenth rotation element N 13 , a fifth planet carrier PC 5 being a fourteenth rotation element N 14 and rotatably supporting a fifth pinion gear P 5 engaged with the fifth sun gear S 5 of the thirteenth rotation element N 13 , and a fifth ring gear R 5 being a fifteenth rotation element N 15 engaged with the fifth pinion gear P 5 .

The second rotation element N 2 is directly connected to the fourth rotation element N 4 , the third rotation element N 3 is directly connected to the seventh rotation element N 7 and the tenth rotation element N 10 , the fifth rotation element N 5 is directly connected to the eighth rotation element N 8 , the sixth rotation element N 6 is directly connected to the thirteenth rotation element N 13 , and the eleventh rotation element N 11 is directly connected to the fifteenth rotation element N 15 such that the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 are operated with nine shafts TM 1 to TM 9 .

The nine shafts TM 1 to TM 9 will be described in further detail.

The nine shafts TM 1 to TM 9 may directly connect rotation elements to each other among the rotation elements of the planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 . The nine shafts TM 1 to TM 9 may be rotation members that are connected to any one rotation element and rotate with the any one rotation element to transmit torque, or rotation members that selectively connect any one rotation element to the transmission housing H. In one form, the nine shafts TM 1 to TM 9 may be fixed members that directly connect any one rotation element to the transmission housing H.

The first shaft TM 1 is directly connected to the first rotation element N 1 (first sun gear S 1 ) and is directly connected to the input shaft IS so as to be always operated as an input element.

The second shaft TM 2 is directly connected to the fourteenth rotation element N 14 (fifth planet carrier PC 5 ) and is directly connected to the output shaft OS so as to be always operated as an output element.

The third shaft TM 3 is directly connected to the sixth rotation element N 6 (second ring gear R 2 ) and the thirteenth rotation element N 13 (fifth sun gear S 5 ).

The fourth shaft TM 4 is directly connected to the eleventh rotation element N 11 (fourth planet carrier PC 4 ) and the fifteenth rotation element N 15 (fifth ring gear R 5 ).

The fifth shaft TM 5 is directly connected to the fifth rotation element N 5 (second planet carrier PC 2 ) and the eighth rotation element N 8 (third planet carrier PC 3 ).

The sixth shaft TM 6 is directly connected to the ninth rotation element N 9 (third ring gear R 3 ).

The seventh shaft TM 7 is directly connected to the third rotation element N 3 (first ring gear R 1 ), the seventh rotation element N 7 (third sun gear S 3 ), and the tenth rotation element N 10 (fourth sun gear S 4 ).

The eighth shaft TM 8 is directly connected to the second rotation element N 2 (first planet carrier PC 1 ) and the fourth rotation element N 4 (second sun gear S 2 ).

The ninth shaft TM 9 is directly connected to the twelfth rotation element N 12 (fourth ring gear R 4 ).

Herein, the second shaft TM 2 is selectively connected to the sixth shaft TM 6 , and each of the third shaft TM 3 and the fifth shaft TM 5 is selectively connected to the first shaft TM 1 so as to be operated as a selective input element.

In addition, each of the seventh shaft TM 7 , the eighth shaft TM 8 , and the ninth shaft TM 9 is selectively connected to the transmission housing H so as to be operated as a selective fixed element.

Three clutches C 1 , C 2 , and C 3 that are engaging elements are disposed at portions at which any two shafts among the nine shafts TM 1 to TM 9 including the input shaft IS and the output shaft OS are selectively connected to each other.

In addition, three brakes B 1 , B 2 , and B 3 that are engaging elements are disposed at portions at which any one shaft among the nine shafts TM 1 to TM 9 is selectively connected to the transmission housing H.

Arrangement of the six engaging elements (three clutches C 1 to C 3 and three brakes B 1 to B 3 ) will be described in detail.

The first clutch C 1 is disposed between the second shaft TM 2 and the sixth shaft TM 6 and selectively connects the second shaft TM 2 to the sixth shaft TM 6 .

The second clutch C 2 is disposed between the first shaft TM 1 and the fifth shaft TM 5 and selectively connects the first shaft TM 1 to the fifth shaft TM 5 .

The third clutch C 3 is disposed between the first shaft TM 1 and the third shaft TM 3 and selectively connects the first shaft TM 1 to the third shaft TM 3 .

The first brake B 1 is disposed between the eighth shaft TM 8 and the transmission housing H and selectively connects the eighth shaft TM 8 to the transmission housing H.

The second brake B 2 is disposed between the seventh shaft TM 7 and the transmission housing H and selectively connects the seventh shaft TM 7 to the transmission housing H.

The third brake B 3 is disposed between the ninth shaft TM 9 and the transmission housing H and selectively connects the ninth shaft TM 9 to the transmission housing H.

Referring to FIG. 1 , it is illustrated that the second clutch C 2 and the third clutch C 3 are selectively connects the fifth shaft TM 5 and the third shaft TM 3 to the first shaft TM 1 , respectively. Since the first shaft TM 1 is directly connected to the input shaft IS, the second clutch C 2 may be configured to selectively connect the input shaft IS to the fifth shaft TM 5 , and the third clutch C 3 may be configured to selectively connect the input shaft IS to the third shaft TM 3 .

The engaging elements including the first, second, and third clutches (i.e., C 1 , C 2 , and C 3 ) and the first, second, and third brakes (i.e., B 1 , B 2 , and B 3 ) may be multi-plates friction elements of wet type that are operated by hydraulic pressure.

FIG. 2 is one example of an operation chart of control elements at each speed stage in the planetary gear train in the first exemplary form of the present disclosure.

Referring to FIG. 2 , three engaging elements among the first, second, and third clutches C 1 , C 2 , and C 3 and the first, second, and third brakes B 1 , B 2 , and B 3 are operated at each speed stage in the planetary gear train.

The third clutch C 3 and the first and third brakes B 1 and B 3 are simultaneously operated at a first forward speed stage D 1 .

In a state that the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , torque of the input shaft IS is input into the first shaft TM 1 and the third shaft TM 3 . In addition, the eighth shaft TM 8 and the ninth shaft TM 9 are operated as the fixed elements by operation of the first and third brakes B 1 and B 3 . Therefore, the torque of the input shaft IS is shifted into the first forward speed stage, and the first forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The third clutch C 3 and the second and third brakes B 2 and B 3 are simultaneously operated at a second forward speed stage D 2 .

In a state that the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 and the third shaft TM 3 . In addition, the seventh shaft TM 7 and the ninth shaft TM 9 are operated as the fixed elements by operation of the second and third brakes B 2 and B 3 . Therefore, the torque of the input shaft Is is shifted into the second forward speed stage, and the second forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The second clutch C 2 and the second and third brakes B 2 and B 3 are simultaneously operated at a third forward speed stage D 3 .

In a state that the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , the torque of the input shaft IS is input into the first shaft TM 1 and the fifth shaft TM 5 . In addition, the seventh shaft TM 7 and the ninth shaft TM 9 are operated as the fixed elements by operation of the second and third brakes B 2 and B 3 . Therefore, the torque of the input shaft IS is shifted into the third forward speed stage, and the third forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The second and third clutches C 2 and C 3 and the third brake B 3 are simultaneously operated at a fourth forward speed stage D 4 .

In a state that the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 and the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 , the fifth shaft TM 5 , and the third shaft TM 3 . In addition, the ninth shaft TM 9 is operated as the fixed element by operation of the third brake B 3 . Therefore, the torque of the input shaft IS is shifted into the fourth forward speed stage, and the fourth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first and second clutches C 1 and C 2 and the third brake B 3 are simultaneously operated at a fifth forward speed stage D 5 .

In a state that the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 and the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , the torque of the input shaft IS is input into the first shaft TM 1 and the fifth shaft TM 5 . In addition, the ninth shaft TM 9 is operated as the fixed element by operation of the third brake B 3 . Therefore, the torque of the input shaft IS is shifted into the fifth forward speed stage, and the fifth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first and third clutches C 1 and C 3 and the third brake B 3 are simultaneously operated at a sixth forward speed stage D 6 .

In a state that the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 and the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 and the third shaft TM 3 . In addition, the ninth shaft TM 9 is operated as the fixed element by operation of the third brake B 3 . Therefore, the torque of the input shaft IS is shifted into the sixth forward speed stage, and the sixth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first, second, and third clutches C 1 , C 2 , and C 3 are simultaneously operated at a seventh forward speed stage D 7 .

If the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 , the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , and the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , all the planetary gear sets become lock-up states. In this state, if the torque of the input shaft IS is input into the first shaft TM 1 , the fifth shaft TM 5 , and the third shaft TM 3 , the torque of the input shaft IS is not changed and the seventh forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first and third clutches C 1 and C 3 and the second brake B 2 are simultaneously operated at an eighth forward speed stage D 8 .

In a state that the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 and the first shaft TM 1 is connected to the third shaft TM 3 by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 and the third shaft TM 3 . In addition, the seventh shaft TM 7 is operated as the fixed element by operation of the second brake B 2 . Therefore, the torque of the input shaft IS is shifted into the eighth forward speed stage, and the eighth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first and second clutches C 1 and C 2 and the second brake B 2 are simultaneously operated at a ninth forward speed stage D 9 .

In a state that the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 and the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , the torque of the input shaft IS is input into the first shaft TM 1 and the fifth shaft TM 5 . In addition, the seventh shaft TM 7 is operated as the fixed element by operation of the second brake B 2 . Therefore, the torque of the input shaft IS is shifted into the ninth forward speed stage, and the ninth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first and second clutches C 1 and C 2 and the first brake B 1 are simultaneously operated at a tenth forward speed stage D 10 .

In a state that the second shaft TM 2 is connected to the sixth shaft TM 6 by operation of the first clutch C 1 and the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , the torque of the input shaft IS is input into the first shaft TM 1 and the fifth shaft TM 5 . In addition, the eighth shaft TM 8 is operated as the fixed element by operation of the first brake B 1 . Therefore, the torque of the input shaft IS is shifted into the tenth forward speed stage, and the tenth forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

The first clutch C 1 and the first and third brakes B 1 and B 3 are simultaneously operated at a reverse speed stage REV.

In a state that the second shaft TM 2 is connected with the sixth shaft TM 6 by operation of the first clutch C 1 , the torque of the input shaft IS is input into the first shaft TM 1 . In addition, the eighth shaft TM 8 and the ninth shaft TM 9 are operated as the fixed elements by operation of the first and third brakes B 1 and B 3 . Therefore, the torque of the input shaft IS is shifted into the reverse speed stage, and the reverse speed stage is output through the output shaft OS connected with the second shaft TM 2 as an inverse rotation speed.

FIG. 3 is another example of an operation chart of control elements at each speed stage in the planetary gear train according to the first exemplary form of the present disclosure.

Referring to FIG. 3 , another example of the operation chart shows that engaging elements at the second forward speed stage D 2 are different from those in the one example shown FIG. 2 .

That is, referring to FIG. 3 , the second clutch C 2 and the first and third brakes B 1 and B 3 are simultaneously operated at the second forward speed stage D 2 .

In a state that the first shaft TM 1 is connected to the fifth shaft TM 5 by operation of the second clutch C 2 , the torque of the input shaft IS is input into the first shaft TM 1 and the fifth shaft TM 5 . In addition, the eighth shaft TM 8 and the ninth shaft TM 9 are operated as the fixed elements by operation of the first and third brakes B 1 and B 3 . Therefore, the torque of the input shaft IS is shifted into the second forward speed stage, and the second forward speed stage is output through the output shaft OS connected with the second shaft TM 2 .

At this time, gear ratio of at each speed stage, step ratios, and gear ratio span may be suitably adjusted referring to operation charts shown in FIG. 2 and FIG. 3 .

FIG. 4 is a schematic diagram of a planetary gear train according to the second exemplary form of the present disclosure.

Referring to FIG. 1 and FIG. 4 , the first clutch C 1 is disposed between the second shaft TM 2 and the sixth shaft TM 6 and selectively connects the second shaft TM 2 to the sixth shaft TM 6 in the planetary gear train according to the first exemplary form of the present disclosure, whereas the first clutch C 1 is disposed between the fourth shaft TM 4 and the sixth shaft TM 6 and selectively connects the fourth shaft TM 4 to the sixth shaft TM 6 in the planetary gear train according to the second exemplary form of the present disclosure.

Nine shafts TM 1 to TM 9 , arrangements of two clutches C 2 and C 3 and three brakes B 1 to B 3 , functions, and operations of the second exemplary form are the same as those of the first exemplary form except arrangement of the first clutch C 1 .

FIG. 5 and FIG. 6 are two examples of an operation chart of control elements at each speed stage in the planetary gear train according to the second exemplary form of the present disclosure.

Operation charts illustrated in FIG. 5 and FIG. 6 are the same as those illustrated in FIG. 2 and FIG. 3 , respectively.

Since arrangement of the first clutch C 1 according to the second exemplary form of the present disclosure is different from that according to the first exemplary form, gear ratio of at each speed stage, step ratios, and gear ratio span may be suitably adjusted referring to FIG. 5 and FIG. 6

According to the first and second exemplary forms of the present disclosure, ten forward speed stages and one reverse speed stage may be achieved by using five planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5 and six engaging elements including three clutches C 1 , C 2 , and C 3 and three brakes B 1 , B 2 , and B 3 .

In addition, since gear ratio span greater than 8.5 is secured, driving efficiency of the engine may be improved. In addition, since linearity of step ratios can be secured due to multiple speed stages, drivability such as acceleration before and after shift, rhythmical engine speed, and so on may be improved.

In addition, since ten forward speed stages and one reverse speed stages are achieved by using the reduced number of engaging elements, drag loss of clutches and brakes may be reduced and thus power delivery efficiency and fuel economy may be improved.

In addition, since a planetary gear set of an output side in torque parallel type is used and torque is evenly shared to each planetary gear set and each engaging element, torque delivery efficiency and durability may be improved.

In addition, since five planetary gear sets are used to achieve ten forward speed stages and one reverse speed stage, flexibility of output gear ratios may be increased and linearity of step ratios may be improved.

While this present disclosure has been described in connection with what is presently considered to be practical forms, it is to be understood that the present disclosure is not limited to the disclosed forms, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the present disclosure.

PG 1 , PG 2 , PG 3 , PG 4 , PG 5 : first, second, third, fourth, and fifth planetary gear sets

S 1 , S 2 , S 3 , S 4 , S 5 : first, second, third, fourth, and fifth sun gears

PC 1 , PC 2 , PC 3 , PC 4 , PC 5 : first, second, third, fourth, and fifth planet carriers

R 1 , R 2 , R 3 , R 4 , R 5 : first, second, third, fourth, and fifth ring gears

C 1 , C 2 , C 3 : first, second, and third clutches

B 1 , B 2 , B 3 : first, second, and third brakes

IS: input shaft

OS: output shaft

TM 1 , TM 2 , TM 3 , TM 4 , TM 5 , TM 6 , TM 7 , TM 8 , TM 9 : first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth shafts