Patent Publication Number: US-10788103-B2

Title: Planetary gear train of automatic transmission for vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2018-0073096 filed on Jun. 26, 2018, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an automatic transmission for a vehicle. More particularly, the present invention relates to a planetary gear train of an automatic transmission for a vehicle that improves power delivery performance and fuel economy by achieving ten forward speeds and widening speed ratio span (or gear ratio span), and secures linearity of step ratios. 
     Description of Related Art 
     Generally, an automatic transmission achieving more speed stages has been developed for enhancing fuel economy and optimizing drivability. 
     Such an automatic transmission achieving more speed stages is necessary to maximize power performance and driving efficiency according to downsizing of an engine. It is desperately demanded to develop high efficiency multiple-speed transmissions having excellent linearity of step ratios which may be used as an index closely related to drivability such as acceleration before and after shift and rhythmical engine speed to secure competitiveness of 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 achieve maximum efficiency with a small number of components may be important to increase fuel efficiency enhancement effect through the multiple-speeds. 
     In the present background, an eight-speed automatic transmission has been introduced recently and a planetary gear train for an automatic transmission facilitating more speed stages is under investigation. 
     However, since 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), improvement of power performance and fuel economy may not be great. 
     Furthermore, even though 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 deteriorate, and thus, development of high efficiency automatic transmissions which achieve at least nine forward speeds is necessary. 
     The information included in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY 
     Various aspects of the present invention are directed to providing a planetary gear train of an automatic transmission for a vehicle having advantages of improving power delivery performance and fuel economy by achieving ten forward speeds and one reverse speed and reducing drag loss of clutches and brakes using five planetary gear sets but six engaging elements. 
     Various aspects of the present invention are directed to providing a planetary gear train of an automatic transmission for a vehicle having further advantages of improving torque delivery efficiency and durability by applying torque parallel way to a planetary gear set at an output side and minimizing torque share of each planetary gear set and each engaging element. 
     Various aspects of the present invention are directed to providing 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 use of five planetary gear sets for achieving ten forward speeds and one reverse speed. 
     A planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention may include: an input shaft receiving torque of 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 fixedly connected to the second rotation element and the input shaft; a second shaft fixedly connected to the fourteenth rotation element and the output shaft; a third shaft fixedly connected to the third rotation element and the fourth rotation element; a fourth shaft fixedly connected to the fifth rotation element; a fifth shaft fixedly connected to the sixth rotation element, the seventh rotation element, and the thirteenth rotation element; a sixth shaft fixedly connected to the eleventh rotation element and the fifteenth rotation element; a seventh shaft fixedly connected to the first rotation element and the eighth rotation element; an eighth shaft fixedly connected to the ninth rotation element and the tenth rotation element; and a ninth shaft fixedly connected to the twelfth rotation element. 
     The planetary gear train may further include six engaging elements, each selectively connecting any one shaft with another shaft or any one shaft with a transmission housing, wherein the second planetary gear set is locked-up by any one of the six engaging element, and wherein forward speeds or reverse speeds are achieved by operating any three engaging elements among the six engaging elements. 
     The six engaging elements may include: three clutches, each selectively connecting any two shafts among the nine shafts; and three brakes, each selectively connecting any one shaft among the nine shafts which is not connected to the input shaft nor the output shaft with the transmission housing. 
     In one aspect, the six engaging elements may include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the third shaft and the fifth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     In another aspect, the six engaging elements may include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the third shaft and the fourth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     In other aspect, the six engaging elements may include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the fourth shaft and the fifth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     The first rotation element may be a first sun gear, the second rotation element may be a first planet carrier, and the third rotation element may be a first ring gear. The fourth rotation element may be a second sun gear, the fifth rotation element may be a second planet carrier, and the sixth rotation element may be a second ring gear. The seventh rotation element may be a third sun gear, the eighth rotation element may be a third planet carrier, and the ninth rotation element may be a third ring gear. The tenth rotation element may be a fourth sun gear, the eleventh rotation element may be a fourth planet carrier, and the twelfth rotation element may be a fourth ring gear. The thirteenth rotation element may be a fifth sun gear, the fourteenth rotation element may be a fifth planet carrier, and the fifteenth rotation element may be a fifth ring gear. 
     The first, second, third, fourth, and fifth planetary gear sets may be disposed in a sequence of the first, second, third, fourth, and fifth planetary gear sets from an engine side thereof. 
     A planetary gear train of an automatic transmission for a vehicle according to various exemplary embodiments of the present invention may include: an input shaft receiving torque of 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 fixedly connected to the second rotation element and the input shaft; a second shaft fixedly connected to the fourteenth rotation element and the output shaft; a third shaft fixedly connected to the third rotation element and the fourth rotation element; a fourth shaft fixedly connected to the fifth rotation element; a fifth shaft fixedly connected to the sixth rotation element, the seventh rotation element, and the thirteenth rotation element; a sixth shaft fixedly connected to the eleventh rotation element and the fifteenth rotation element; and a plurality of shafts formed by combinations of remaining rotation elements among the rotation elements of the first, third, and fourth planetary gear sets that are not connected to the first shaft to the sixth shaft, and each thereof selectively connectable to a transmission housing. 
     The plurality of shafts may include: a seventh shaft fixedly connected to the first rotation element and the eighth rotation element; an eighth shaft fixedly connected to the ninth rotation element and the tenth rotation element; and a ninth shaft fixedly connected to the twelfth rotation element. 
     In one aspect, the planetary gear train may further include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the third shaft and the fifth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     In another aspect, the planetary gear train may further include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the third shaft and the fourth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     In other aspect, the planetary gear train may further include: a first clutch disposed between the second shaft and the fourth shaft; a second clutch disposed between the first shaft and the fifth shaft; a third clutch disposed between the fourth shaft and the fifth shaft; a first brake disposed between the seventh shaft and the transmission housing; a second brake disposed between the eighth shaft and the transmission housing; and a third brake disposed between the ninth shaft and the transmission housing. 
     The first rotation element may be a first sun gear, the second rotation element may be a first planet carrier, and the third rotation element may be a first ring gear. The fourth rotation element may be a second sun gear, the fifth rotation element may be a second planet carrier, and the sixth rotation element may be a second ring gear. The seventh rotation element may be a third sun gear, the eighth rotation element may be a third planet carrier, and the ninth rotation element may be a third ring gear. The tenth rotation element may be a fourth sun gear, the eleventh rotation element may be a fourth planet carrier, and the twelfth rotation element may be a fourth ring gear. The thirteenth rotation element may be a fifth sun gear, the fourteenth rotation element may be a fifth planet carrier, and the fifteenth rotation element may be a fifth ring gear. 
     The first, second, third, fourth, and fifth planetary gear sets may be disposed in a sequence of the first, second, third, fourth, and fifth planetary gear sets from an engine side thereof. 
     A planetary gear train of an automatic transmission for a vehicle according to other exemplary embodiment of the present invention may include: an input shaft receiving torque of 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; and a fifth planetary gear set including thirteenth, fourteenth, and fifteenth rotation elements, wherein the second rotation element is fixedly connected to the input shaft, the fourteenth rotation element is fixedly connected to the output shaft, the first rotation element is fixedly connected to the eighth rotation element and is selectively connectable to a transmission housing, the third rotation element is fixedly connected to the fourth rotation element, the fifth rotation element is selectively connectable to the fourteenth rotation element, the sixth rotation element is fixedly connected to the seventh rotation element and the thirteenth rotation element and is selectively connectable to the second rotation element, the ninth rotation element is fixedly connected to the tenth rotation element and is selectively connectable to the transmission housing, the eleventh rotation element is fixedly connected to the fifteenth rotation element, and the twelfth rotation element is selectively connectable to the transmission housing. 
     Any two rotation elements among the fourth, fifth, and sixth rotation elements of the second planetary gear set may be selectively connectable to each other. 
     In one aspect, the planetary gear train may further include: a first clutch disposed between the fifth rotation element and the fourteenth rotation element; a second clutch disposed between the second rotation element and the sixth rotation element; a third clutch disposed between the fourth rotation element and the sixth rotation element; a first brake disposed between the first rotation element and the transmission housing; a second brake disposed between the ninth rotation element and the transmission housing; and a third brake disposed between the twelfth rotation element and the transmission housing. 
     In another aspect, the planetary gear train may further include: a first clutch disposed between the fifth rotation element and the fourteenth rotation element; a second clutch disposed between the second rotation element and the sixth rotation element; a third clutch disposed between the fourth rotation element and the fifth rotation element; a first brake disposed between the first rotation element and the transmission housing; a second brake disposed between the ninth rotation element and the transmission housing; and a third brake disposed between the twelfth rotation element and the transmission housing. 
     In other aspect, the planetary gear train may further include: a first clutch disposed between the fifth rotation element and the fourteenth rotation element; a second clutch disposed between the second rotation element and the sixth rotation element; a third clutch disposed between the fifth rotation element and the sixth rotation element; a first brake disposed between the first rotation element and the transmission housing; a second brake disposed between the ninth rotation element and the transmission housing; and a third brake disposed between the twelfth rotation element and the transmission housing. 
     According to exemplary embodiments of the present invention, ten forward speeds and one reverse speed may be achieved by combining five planetary gear sets being simple planetary gear sets with six engaging elements. 
     Furthermore, since gear ratio span greater than 9.0 is secured, driving efficiency of the engine may be maximized. Furthermore, since linearity of step ratios may be secured due to multiple speed stages, drivability such as acceleration before and after shift, rhythmical engine speed, and the like may be improved. 
     Furthermore, since ten forward speeds and one reverse speed are achieved by use of five planetary gear sets but the number of engaging elements is minimized, drag loss of clutches and brakes may be reduced and power delivery efficiency and fuel economy may be improved. 
     Furthermore, since torque parallel way is applied to a planetary gear set at an output side and a torque is evenly shared to each planetary gear set and each engaging element, torque delivery efficiency and durability may be improved. 
     Furthermore, since five planetary gear sets are used to achieve ten forward speeds and one reverse speed, flexibility of output gear ratios may be increased and linearity of step ratios may be improved. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention. 
         FIG. 2  is an operation chart of engaging elements at each speed stage in the planetary gear train according to the various exemplary embodiments of the present invention. 
         FIG. 3  is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention. 
         FIG. 4  is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention. 
     
    
    
     It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as included herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the other hand, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Hereinafter, various exemplary embodiments of the present invention 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 embodiments of the present invention and like reference numerals refer to like or similar elements throughout the specification. 
     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 various exemplary embodiments of the present invention. 
     Referring to  FIG. 1 , a planetary gear train according to various exemplary embodiments of the present invention 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, an 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 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 various exemplary embodiments of the present invention, the planetary gear sets are disposed in a sequence of the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5  from an engine side on an axis of the input shaft IS. 
     The input shaft IS is an input member and a 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 element, 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  as a first rotation element N 1 , a first planet carrier PC 1  as a second rotation element N 2  that rotatably supports a plurality of first pinion gears P 1  disposed evenly at an external circumference of the first sun gear S 1  and engaged with the first sun gear S 1 , and a first ring gear R 1  as a third rotation element N 3  which is engaged with the first pinion gears P 1  at a radial external of the plurality of first pinion gears P 1  to be operably connected to the first sun gear S 1 . 
     The second planetary gear set PG 2  is a single pinion planetary gear set and includes a second sun gear S 2  as a fourth rotation element N 4 , a second planet carrier PC 2  as a fifth rotation element N 5  that rotatably supports a plurality of second pinion gears P 2  disposed evenly at an external circumference of the second sun gear S 2  and engaged with the second sun gear S 2 , and a second ring gear R 2  as a sixth rotation element N 6  which is engaged with the second pinion gears P 2  at a radial external of the plurality of second pinion gears P 2  to be operably connected to the second sun gear S 2 . 
     The third planetary gear set PG 3  is a single pinion planetary gear set and includes a third sun gear S 3  as a seventh rotation element N 7 , a third planet carrier PC 3  as an eighth rotation element N 8  that rotatably supports a plurality of third pinion gears P 3  disposed evenly at an external circumference of the third sun gear S 3  and engaged with the third sun gear S 3 , and a third ring gear R 3  as a ninth rotation element N 9  which is engaged with the third pinion gears P 3  at a radial external of the plurality of third pinion gears P 3  to be operably connected to the third sun gear S 3 . 
     The fourth planetary gear set PG 4  is a single pinion planetary gear set and includes a fourth sun gear S 4  as a tenth rotation element N 10 , a fourth planet carrier PC 4  as an eleventh rotation element N 11  that rotatably supports a plurality of fourth pinion gears P 4  disposed evenly at an external circumference of the fourth sun gear S 4  and engaged with the fourth sun gear S 4 , and a fourth ring gear R 4  as a twelfth rotation element N 12  which is engaged with the fourth pinion gears P 4  at a radial external of the plurality of fourth pinion gears P 4  to be operably connected to the fourth sun gear S 4 . 
     The fifth planetary gear set PG 5  is a single pinion planetary gear set and includes a fifth sun gear S 5  as a thirteenth rotation element N 13 , a fifth planet carrier PC 5  as a fourteenth rotation element N 14  that rotatably supports a plurality of fifth pinion gears P 5  disposed evenly at an external circumference of the fifth sun gear S 5  and engaged with the fifth sun gear S 5 , and a fifth ring gear R 5  as a fifteenth rotation element N 15  which is engaged with the fifth pinion gears P 5  at a radial external of the plurality of fifth pinion gears P 5  to be operably connected to the fifth sun gear S 5 . 
     Here, the term “operably connected” or the like means at least two members are directly or indirectly connected to each other. However, two members that are operably connected to each other do not always rotate with the same rotation speed and in the same rotation direction thereof. 
     Here, the first rotation element N 1  is fixedly connected to the eighth rotation element N 8 , the third rotation element N 3  is fixedly connected to the fourth rotation element N 4 , the sixth rotation element N 6  is fixedly connected to the seventh rotation element N 7  and the thirteenth rotation element N 13 , the ninth rotation element N 9  is fixedly connected to the tenth rotation element N 10 , and the eleventh rotation element N 11  is fixedly 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  include nine shafts TM 1  to TM 9 . 
     Here, the term “fixedly connected” or the like means at least two members are connected to each other to always rotate without rotation speed difference. That is, at least two members that are fixedly connected to each other always rotate with the same rotation speed and in the same rotation direction thereof. Therefore, it is to be understood by a person of an ordinary skill in the art that the term “fixedly connected” or the like differs from the term “operably connected” or the like. 
     The nine shafts TM 1  to TM 9  will be described in further detail. 
     The first shaft TM 1  is fixedly connected to the second rotation element N 2  (first planet carrier PC 1 ) and is fixedly connected to the input shaft IS to be continuously operated as an input element. 
     The second shaft TM 2  is fixedly connected to the fourteenth rotation element N 14  (fifth planet carrier PC 5 ) and is fixedly connected to the output shaft OS to be continuously operated as an output element. 
     The third shaft TM 3  is fixedly connected to the third rotation element N 3  (first ring gear R 1 ) and the fourth rotation element N 4  (second sun gear S 2 ). 
     The fourth shaft TM 4  is fixedly connected to the fifth rotation element N 5  (second planet carrier PC 2 ). 
     The fifth shaft TM 5  is fixedly connected to the sixth rotation element N 6  (second ring gear R 2 ), the seventh rotation element N 7  (third sun gear S 3 ), and the thirteenth rotation element N 13  (fifth sun gear S 5 ). 
     The sixth shaft TM 6  is fixedly 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 seventh shaft TM 7  is fixedly connected to the first rotation element N 1  (first sun gear S 1 ) and the eighth rotation element N 8  (third planet carrier PC 3 ). 
     The eighth shaft TM 8  is fixedly connected to the ninth rotation element N 9  (third ring gear R 3 ) and the tenth rotation element N 10  (fourth sun gear S 4 ). 
     The ninth shaft TM 9  is fixedly connected to the twelfth rotation element N 12  (fourth ring gear R 4 ). 
     The nine shafts TM 1  to TM 9  fixedly connects a plurality of rotation elements among the rotation elements of the planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5  with each other, are rotation members that are connected to any one rotation element and rotate with the any one rotation element to transmit torque, are rotation members that selectively connect any one rotation element with the transmission housing H, or are fixed members that directly connect any one rotation element to the transmission housing H. 
     Here, the term “selectively connectable” or the like means that a plurality of shafts including the input shaft and the output shaft are connectable to each other through at least one of the engaging elements to rotate with the same rotation speed and in the same rotation direction thereof, or are connectable to the transmission housing through at least one of the engaging elements to be fixed to the transmission housing. 
     In other words, in a case that the engaging element selectively connects a plurality of shafts to each other, the plurality of shafts rotates with the same rotation speed and in the same rotation direction when the engaging element operates but the plurality of shafts are disconnected from each other when the engaging element is released. 
     Furthermore, in a case that the engaging element selectively connects any one shaft to the transmission housing, the corresponding shaft is fixedly connected to the transmission housing when the engaging element operates but the corresponding shaft is rotatable when the engaging element is released. 
     Furthermore, in a case that the engaging element selectively connects any one shaft to the transmission housing, the corresponding shaft is fixedly connected to the transmission housing when the engaging element operates but the corresponding shaft is rotatable when the engaging element is released. 
     Here, the second shaft TM 2  is selectively connectable to the fourth shaft TM 4 , and each of the first shaft TM 1  and the third shaft TM 3  is selectively connectable to the fifth shaft TM 5 . 
     Furthermore, each of the seventh shaft TM 7 , the eighth shaft TM 8 , and the ninth shaft TM 9  is selectively connectable to the transmission housing H 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 connectable to each other. 
     Furthermore, 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 connectable 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 fourth shaft TM 4  and selectively connects the second shaft TM 2  to the fourth shaft TM 4 . 
     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 third shaft TM 3  and the fifth shaft TM 5  and selectively connects the third shaft TM 3  to the fifth shaft TM 5 . 
     The first brake B 1  is disposed between the seventh shaft TM 7  and the transmission housing H and selectively connects and fixes the seventh shaft TM 7  to the transmission housing H. 
     The second brake B 2  is disposed between the eighth shaft TM 8  and the transmission housing H and selectively connects and fixes the eighth shaft TM 8  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 and fixes the ninth shaft TM 9  to the transmission housing H. 
     The engaging elements including 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  may be multi-plates friction elements of wet type that are operated by hydraulic pressure. Multi-plates friction elements of wet type are mainly used as the engaging elements, but dog clutches, electric clutches, or magnetic clutches which may be operated by electric signal from an electric control unit may be used as the engaging elements. 
       FIG. 2  is an operation chart of engaging elements at each speed stage in the planetary gear train according to the various exemplary embodiments of the present invention. 
     Referring to  FIG. 2 , any three combinations 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 to achieve ten forward speeds and one reverse speed. Shifting processes will be described. 
     The second clutch C 2  and the first and third brakes B 1  and B 3  are operated at a first forward speed D 1 . 
     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 , torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, the seventh and ninth shafts TM 7  and 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, and the first forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The second clutch C 2  and the second and third brakes B 2  and B 3  are operated at a second forward speed 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 . 
     At the present state, the eighth and ninth shafts TM 8  and 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, and the second forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The third clutch C 3  and the second and third brakes B 2  and B 3  are operated at a third forward speed D 3 . 
     In a state that the third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, the eighth and ninth shafts TM 8  and 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, and the third forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The second and third clutches C 2  and C 3  and the third brake B 3  are operated at a fourth forward speed 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 third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, 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, and the fourth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first and third clutches C 1  and C 3  and the third brake B 3  are operated at a fifth forward speed D 5 . 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  by operation of the first clutch C 1  and the third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, 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, and the fifth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first clutch and second clutch C 1  and C 2  and the third brake B 3  are operated at a sixth forward speed D 6 . 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  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 . 
     At the present state, 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, and the sixth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first, second, and third clutches C 1 , C 2 , and C 3  are operated at a seventh forward speed D 7 . 
     The second shaft TM 2  is connected to the fourth shaft TM 4  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 third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 . 
     In the instant case, the first, second, third, fourth, and fifth planetary gear sets PG 1 , PG 2 , PG 3 , PG 4 , and PG 5  become lock-up states. Therefore, the torque of the input shaft IS input to the first shaft TM 1  is output through the output shaft OS fixedly connected to the second shaft TM 2  without change of rotation speed. 
     The first clutch and second clutch C 1  and C 2  and the second brake B 2  are operated at an eighth forward speed D 8 . 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  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 . 
     At the present state, the eighth shaft TM 8  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, and the eighth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first and third clutches C 1  and C 3  and the second brake B 2  are operated at a ninth forward speed D 9 . 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  by operation of the first clutch C 1  and the third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, the eighth shaft TM 8  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, and the ninth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first and third clutches C 1  and C 3  and the first brake B 1  are operated at a tenth forward speed D 10 . 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  by operation of the first clutch C 1  and the third shaft TM 3  is connected to the fifth shaft TM 5  by operation of the third clutch C 3 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, the seventh shaft TM 7  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, and the tenth forward speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
     The first clutch C 1  and first and third brakes B 1  and B 3  are operated at a reverse speed REV. 
     In a state that the second shaft TM 2  is connected to the fourth shaft TM 4  by operation of the first clutch C 1 , the torque of the input shaft IS is input into the first shaft TM 1 . 
     At the present state, the seventh and ninth shafts TM 7  and 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, and the reverse speed is output through the output shaft OS fixedly connected to the second shaft TM 2 . 
       FIG. 3  is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention. 
     Structures and operation of the planetary gear train according to the various exemplary embodiments of the present invention are similar to those of the planetary gear train according to the various exemplary embodiments of the present invention. Therefore, differences between the various exemplary embodiments and the various exemplary embodiments will be described. 
     Referring to  FIG. 1  and  FIG. 3 , the third clutch C 3  is disposed between the third shaft TM 3  and the fifth shaft TM 5  and selectively connects the third shaft TM 3  to the fifth shaft TM 5  in the planetary gear train in  FIG. 1  according to the various exemplary embodiments of the present invention, but the third clutch C 3  is disposed between the third shaft TM 3  and the fourth shaft TM 4  and selectively connects the third shaft TM 3  to the fourth shaft TM 4  in the planetary gear train in  FIG. 3  according to the various exemplary embodiments of the present invention. 
       FIG. 4  is a schematic diagram of a planetary gear train according to various exemplary embodiments of the present invention. 
     Structures and operation of the planetary gear train according to the various exemplary embodiments of the present invention are similar to those of the planetary gear train according to the various exemplary embodiments of the present invention. Therefore, differences between the various exemplary embodiments and the various exemplary embodiments will be described. 
     Referring to  FIG. 1  and  FIG. 4 , the third clutch C 3  is disposed between the third shaft TM 3  and the fifth shaft TM 5  and selectively connects the third shaft TM 3  to the fifth shaft TM 5  in the planetary gear train in  FIG. 1  according to the various exemplary embodiments of the present invention, but the third clutch C 3  is disposed between the fourth shaft TM 4  and the fifth shaft TM 5  and selectively connects the fourth shaft TM 4  to the fifth shaft TM 5  in the planetary gear train in  FIG. 4  according to the various exemplary embodiments of the present invention. 
     According to the exemplary embodiments of the present invention, ten forward speeds and one reverse speed may be achieved by use of 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 . 
     Furthermore, since gear ratio span greater than 9.0 is secured, driving efficiency of the engine may be maximized. Furthermore, since linearity of step ratios may be secured due to multiple speed stages, drivability such as acceleration before and after shift, rhythmical engine speed, and the like may be improved. 
     Furthermore, since ten forward speeds and one reverse speeds are achieved by use of the minimized number of engaging elements, drag loss of clutches and brakes may be reduced and power delivery efficiency and fuel economy may be improved. 
     Furthermore, since torque parallel way is applied to a planetary gear set at an output side and a torque is evenly shared to each planetary gear set and each engaging element, torque delivery efficiency and durability may be improved. 
     Furthermore, since five planetary gear sets are used to achieve ten forward speeds and one reverse speed, flexibility of output gear ratios may be increased and linearity of step ratios may be improved. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”, “upper”, “lower”, “upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”, “inwardly”, “outwardly”, “internal”, “external”, “inner”, “outer”, “forwards”, and “backwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and their practical application, to enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.