Planetary gear train of an automatic transmission for a vehicle

This application claims priority to and the benefit of Korean Patent Application No. 10-2017-0117416 filed in the Korean Intellectual Property Office on Sep. 13, 2017, the entire contents of which are incorporated herein by reference.

(a) Field of the Disclosure

The present disclosure relates to automatic transmissions for vehicles. More particularly, the present disclosure relates to a planetary gear train of an automatic transmission of a vehicle.

(b) Description of the Related Art

Research on realizing more shift-stages of automatic transmissions has been conducted to enhance vehicle fuel consumption and drivability. Increasing oil prices have triggered fierce competition to enhance vehicle fuel consumption.

Research into weight reduction and enhanced fuel consumption through downsizing of an engine has been conducted. Research has also been conducted on automatic transmissions to simultaneously provide better drivability and fuel consumption by achieving more shift stages.

In order to achieve more shift stages for an automatic transmission, the number of parts is typically increased. As a result, this may deteriorate the installability, production cost, weight and/or power flow efficiency.

Eight-speed automatic transmissions have been recently introduced, and a planetary gear train for an automatic transmission enabling more shift stages is under investigation.

An automatic transmission of eight or more shift-stages typically includes three to four planetary gear sets and five to seven engagement elements (frictional elements). As a result, the automatic transmission may easily become lengthy, thereby deteriorating installability.

Disposing planetary gear sets in parallel or employing dog clutches instead of wet-type control elements has been attempted. However, such an arrangement may not be widely applicable, and using dog clutches may easily deteriorate shift-feel.

The above information disclosed in this Background section is only to enhance understanding of the background of the disclosure. Therefore, the background may contain information that is not prior art that is already known in this country to a person of ordinary skill in the art.

The present disclosure relates to a planetary gear train of an automatic transmission for a vehicle. The disclosed planetary gear train enables at least ten forward speeds, thereby improving vehicle performance and fuel efficiency.

A planetary gear train according to an embodiment may include an input shaft for receiving an engine torque, an output shaft for outputting a shifted torque, a first planetary gear set having first, second, and third rotational elements, a second planetary gear set having fourth, fifth, and sixth rotational elements, a third planetary gear set having seventh, eighth, and ninth rotational elements, and a fourth planetary gear set having tenth, eleventh, and twelfth rotational elements. An exemplary planetary gear train may further include: a first shaft fixedly connected with the ninth rotational element and selectively connected with the input shaft; a second shaft fixedly connected with the twelfth rotational element and selectively connected with the input shaft; a third shaft fixedly connected with the eighth rotational element and the tenth rotational element, and fixedly connected with the output shaft; a fourth shaft fixedly connected with the first rotational element, the fifth rotational element, and the eleventh rotational element; a fifth shaft fixedly connected with the third rotational element, the sixth rotational element, and the seventh rotational element; and a plurality of additional shafts each selectively connecting a corresponding element to a transmission housing, the corresponding element being a rotational element of the first or second planetary gear sets that is not fixedly interconnected.

The plurality of additional shafts may include a sixth shaft fixedly connected with the second rotational element and selectively connected with the transmission housing, and a seventh shaft fixedly connected with the fourth rotational element and selectively connected with the transmission housing. The input shaft and the first shaft, the input shaft and the second shaft, the first shaft and the fourth shaft, and the second shaft and the seventh shaft may be selectively interconnected with each other respectively.

The exemplary planetary gear train may further include four clutches each selectively connecting a corresponding pair of shafts selected among the input shaft, the output shaft, and the first to seventh shafts. The exemplary planetary gear train may also include two brakes selectively connecting the sixth shaft and the seventh shaft to the transmission housing, respectively.

The four clutches may include a first clutch arranged between the input shaft and the first shaft, a second clutch arranged between the input shaft and the second shaft, a third clutch arranged between the first shaft and the fourth shaft, and a fourth clutch arranged between the second shaft and the seventh shaft. The two brakes may include a first brake arranged between the sixth shaft and the transmission housing, and a second brake arranged between the seventh shaft and the transmission housing.

The first planetary gear set may be a single pinion planetary gear set having a first sun gear, a first planet carrier, and a first ring gear as the first, second, and third rotational elements, respectively. The second planetary gear set may be a single pinion planetary gear set having a second sun gear, a second planet carrier, and a second ring gear as the fourth, fifth, and sixth rotational elements, respectively. The third planetary gear set may be a single pinion planetary gear set having a third sun gear, a third planet carrier, and a third ring gear as the seventh, eighth, and ninth rotational elements, respectively. The fourth planetary gear set may be a single pinion planetary gear set having a fourth sun gear, a fourth planet carrier, and a fourth ring gear as the tenth, eleventh, and twelfth rotational elements, respectively.

The first, second, third, and fourth planetary gear sets may be arranged in the order of the first, second, fourth, and third planetary gear sets from an engine side.

A planetary gear train according to an embodiment of the present disclosure may realize at least ten forward speeds and one reverse speed by combination of four planetary gear sets together with six engagement elements.

In addition, a planetary gear train according to an embodiment of the present disclosure may substantially improve driving stability by realizing shift-stages appropriate for the rotation speed of an engine due to multi-stages of an automatic transmission.

In addition, a planetary gear train according to an embodiment of the present disclosure may maximize engine driving efficiency by multi-stages of an automatic transmission. The planetary gear train according to an embodiment of the present disclosure may also improve power delivery performance and fuel consumption.

Further, effects that can be obtained or expected from embodiments of the present disclosure are directly or suggestively described in the detailed description below. In other words, various effects expected from embodiments of the present disclosure will be described in the detailed description below.

FIG. 1 is a schematic diagram of a planetary gear train according to an embodiment of the present disclosure.

FIG. 2 is an operational chart for respective control elements at respective shift-stages applicable to a planetary gear train according to an embodiment of the present disclosure.

It is desired to develop a planetary gear train capable of representing maximum efficiency by a small number of parts in order to increase fuel efficiency through multi-staging of speed changes or gear shifts. In one example, development of high efficiency automatic transmissions, which achieve at least ten forward speed stages, is desirable. In this aspect, the present disclosure relates to a planetary gear train of an automatic transmission for a vehicle. The disclosed planetary gear train may improve power delivery performance and reduce fuel consumption by implementing a speed change stage of at least ten forward speeds using a minimum number of parts.

Hereinafter, one embodiment of the present disclosure is described in detail with reference to drawings. In the drawings, the following symbols are used to identify various elements of the disclosed embodiments, wherein:

i. B 1 , B 2 represent first and second brakes; ii. C 1 , C 2 , C 3 , C 4 represent first, second, third, and fourth clutches; iii. N 1 , N 2 , N 3 , N 4 , N 5 , N 6 , N 7 , N 8 , N 9 , N 10 , N 11 , N 12 represent first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth rotational elements; iv. PG 1 , PG 2 , PG 3 , PG 4 represent first, second, third, and fourth planetary gear sets; v. S 1 , S 2 , S 3 , S 4 represent first, second, third, and fourth sun gears; vi. PC 1 , PC 2 , PC 3 , PC 4 represent first, second, third, and fourth planet carriers; vii. R 1 , R 2 , R 3 , R 4 represent first, second, third, and fourth ring gears; viii. P 1 , P 2 , P 3 , P 4 represent first, second, third, and fourth pinion gears; ix. IS represents an input shaft; x. OS represents an output shaft; and xi. TM 1 , TM 2 , TM 3 , TM 4 , TM 5 , TM 6 , TM 7 represent first, second, third, fourth, fifth, sixth, and seventh shafts.

The drawings and description are to be regarded as illustrative in nature and not restrictive. Also, like reference numerals designate like elements throughout the specification.

In the following description, using names or terms to identify components such as first, second, third, and the like is to differentiate the names because the names of the components are otherwise the same as each other. Such a naming convention is not intended to denote or set an order thereof and the disclosure is not intended to be so limited.

FIG. 1 is a schematic diagram of a planetary gear train according to one embodiment of the present disclosure.

Referring to FIG. 1 , a planetary gear train according to one embodiment of the present disclosure includes first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 arranged on a same axis. In one embodiment, the planetary gear train also includes an input shaft IS, an output shaft OS, seven shafts TM 1 -TM 7 interconnecting rotational elements of the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 , engagement elements of four clutches C 1 -C 4 and two brakes B 1 and B 2 , and a transmission housing H.

Torque input from the input shaft IS is shifted by cooperative operation of the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 . The shifted torque is then output through the output shaft OS.

In this embodiment, the planetary gear sets are arranged in the order of the first, second, fourth, and third planetary gear sets PG 1 , PG 2 , PG 4 , and PG 3 , from an engine side.

The input shaft IS is an input member and may receive a torque from a crankshaft of an engine through a torque converter.

The output shaft OS is an output member arranged on the same axis as the input shaft IS. The output shaft OS outputs a shifted driving torque to a driveshaft through a differential apparatus.

In this embodiment, the first planetary gear set PG 1 is a single pinion planetary gear set. The first planetary gear set PG 1 includes a first sun gear S 1 , a first planet carrier PC 1 rotatably supporting a plurality of first pinion gears P 1 externally gear-meshed with the first sun gear S 1 , and a first ring gear R 1 internally gear-meshed with the plurality of first pinion gears P 1 engaged with the first sun gear S 1 . The first sun gear S 1 acts as a first rotational element N 1 , the first planet carrier PC 1 acts as a second rotational element N 2 , and the first ring gear R 1 acts as a third rotational element N 3 .

In this embodiment, the second planetary gear set PG 2 is a single pinion planetary gear set. The second planetary gear set PG 2 includes a second sun gear S 2 , a second planet carrier PC 2 rotatably supporting a plurality of second pinion gears P 2 externally gear-meshed with the second sun gear S 2 , and a second ring gear R 2 internally gear-meshed with the plurality of second pinion gears P 2 engaged with the second sun gear S 2 . The second sun gear S 2 acts as a fourth rotational element N 4 , the second planet carrier PC 2 acts as a fifth rotational element N 5 , and the second ring gear R 2 acts as a sixth rotational element N 6 .

In this embodiment, the third planetary gear set PG 3 is a single pinion planetary gear set. The third planetary gear set PG 3 includes a third sun gear S 3 , a third planet carrier PC 3 rotatably supporting a plurality of third pinion gears P 3 externally gear-meshed with the third sun gear S 3 , and a third ring gear R 3 internally gear-meshed with the plurality of third pinion gears P 3 engaged with the third sun gear S 3 . The third sun gear S 3 acts as a seventh rotational element N 7 , the third planet carrier PC 3 acts as an eighth rotational element N 8 , and the third ring gear R 3 acts as a ninth rotational element N 9 .

In this embodiment, the fourth planetary gear set PG 4 is a single pinion planetary gear set. The fourth planetary gear set PG 4 includes a fourth sun gear S 4 , a fourth planet carrier PC 4 rotatably supporting a plurality of fourth pinion gears P 4 externally gear-meshed with the fourth sun gear S 4 , and a fourth ring gear R 4 internally gear-meshed with the plurality of fourth pinion gears P 4 engaged with the fourth sun gear S 4 . The fourth sun gear S 4 acts as a tenth rotational element N 10 , the fourth planet carrier PC 4 acts as an eleventh rotational element N 11 , and the fourth ring gear R 4 acts as a twelfth rotational element N 12 .

In the arrangement of the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 , the first rotational element N 1 is fixedly connected with the fifth rotational element N 5 and the eleventh rotational element N 11 , the third rotational element N 3 is fixedly connected with the sixth rotational element N 6 and the seventh rotational element N 7 , and the eighth rotational element N 8 is fixedly connected with the tenth rotational element N 10 , thereby forming seven shafts TM 1 -TM 7 .

The seven shafts TM 1 -TM 7 are described in further detail below.

In this embodiment, the first shaft TM 1 is fixedly connected with the ninth rotational element N 9 (third ring gear R 3 ). The first shaft TM 1 is also selectively connected with the input shaft IS, thereby selectively acting as an input element.

In this embodiment, the second shaft TM 2 is fixedly connected with the twelfth rotational element N 12 (fourth ring gear R 4 ). The second shaft TM 2 is also selectively connected with the input shaft IS, thereby selectively acting as an input element.

In this embodiment, the third shaft TM 3 is fixedly connected with the eighth rotational element N 8 (third planet carrier PC 3 ) and the tenth rotational element N 10 (fourth sun gear S 4 ). The third shaft TM 3 is also fixedly connected with the output shaft OS, thereby always acting as an output element.

In this embodiment, the fourth shaft TM 4 is fixedly connected with the first rotational element N 1 (first sun gear S 1 ), the fifth rotational element N 5 (second planet carrier PC 2 ), and the eleventh rotational element N 11 (fourth planet carrier PC 4 ).

In this embodiment, the fifth shaft TM 5 is fixedly connected with the third rotational element N 3 (first ring gear R 1 ), the sixth rotational element N 6 (second ring gear R 2 ), and the seventh rotational element N 7 (third sun gear S 3 ).

In this embodiment, the sixth shaft TM 6 is fixedly connected with the second rotational element N 2 (first planet carrier PC 1 ).

In this embodiment, the seventh shaft TM 7 is fixedly connected with the fourth rotational element N 4 (second sun gear S 2 ).

Each of the seven shafts TM 1 -TM 7 may be a rotational member that fixedly interconnects the input and output shafts and rotational elements of the planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 . Each of the seven shafts TM 1 -TM 7 may also be a rotational member that selectively interconnects a rotational element to the transmission housing H. Each of the seven shafts TM 1 -TM 7 may also be a fixed member fixed to the transmission housing H.

In the disclosure, when two or more members are described as being “fixedly connected,” where each of the two or more members may be any of a shaft, an input shaft, an output shaft, a rotational member, or a transmission housing, it means that the fixedly connected members always rotate at a same speed.

When two or more members are described as being “selectively connected” by an engagement element, it means that the selectively connected members rotate separately when the engagement element is not engaged, and rotate at a same speed when the engagement element is engaged. It may be understood that in the case that a member is “selectively connected” with a transmission housing by an engagement element, the member may be stationary when the engagement element is engaged.

In this embodiment, the first shaft TM 1 is selectively connected with the input shaft IS, the second shaft TM 2 is selectively connected with the input shaft IS, the first shaft TM 1 is selectively connected with the fourth shaft TM 4 , and the second shaft TM 2 is selectively connected with the seventh shaft TM 7 .

In this embodiment, the sixth shaft TM 6 and the seventh shaft TM 7 are selectively connected with the transmission housing H, thereby selectively acting as fixed elements, respectively.

In this embodiment, the engagement elements of the four clutches C 1 , C 2 , C 3 , and C 4 are arranged between the seven shafts TM 1 -TM 7 , the input shaft IS, and the output shaft OS, so as to form selective connections.

The seven shafts TM 1 -TM 7 may be selectively connected with the transmission housing H by control elements of two brakes B 1 and B 2 .

The six engagement elements of the four clutches C 1 -C 4 and the two brakes B 1 and B 2 are arranged as follows for this embodiment.

The first clutch C 1 is arranged between the input shaft IS and the first shaft TM 1 . The first clutch C 1 selectively connects the input shaft IS and the first shaft TM 1 , thereby controlling power delivery therebetween.

The second clutch C 2 is arranged between the input shaft IS and the second shaft TM 2 . The second clutch C 2 selectively connects the input shaft IS and the second shaft TM 2 , thereby controlling power delivery therebetween.

The third clutch C 3 is arranged between the first shaft TM 1 and the fourth shaft TM 4 . The third clutch C 3 selectively connects the first shaft TM 1 and the fourth shaft TM 4 , thereby controlling power delivery therebetween.

The fourth clutch C 4 is arranged between the second shaft TM 2 and the seventh shaft TM 7 . The fourth clutch C 4 selectively connects the second shaft TM 2 and the seventh shaft TM 7 , thereby controlling power delivery therebetween.

The first brake B 1 is arranged between the sixth shaft TM 6 and the transmission housing H. The first brake B 1 selectively connects the sixth shaft TM 6 to the transmission housing H.

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

The engagement elements of the first, second, third, and fourth clutches C 1 , C 2 , C 3 , and C 4 and the first and second brakes B 1 and B 2 may be multi-plate hydraulic pressure friction devices that are frictionally engaged by hydraulic pressure. However, it should be understood that the engagement elements are not to be limited thereto, since various other configurations that are electrically controllable may be available.

FIG. 2 is an operational chart for respective control elements at respective shift-stages applicable to a planetary gear train according to an embodiment of the present disclosure.

Referring to FIG. 2 , a planetary gear train according to an embodiment of the present disclosure realizes shifting between ten forward speeds and one reverse speed by operating three elements among the engagement elements of the first, second, third, and fourth clutches C 1 , C 2 , C 3 , and C 4 and the first and second brakes B 1 and B 2 .

In this embodiment, in the forward first speed D 1 , the second and third clutches C 2 and C 3 and the first brake B 1 are simultaneously operated.

As a result, the second shaft TM 2 is connected with the input shaft IS by the operation of the second clutch C 2 , and the first shaft TM 1 is connected with the fourth shaft TM 4 by the operation of the third clutch C 3 . In this state, a torque is input to the second shaft TM 2 .

In addition, the sixth shaft TM 6 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward first speed D 1 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward second speed D 2 , the first and third clutches C 1 and C 3 and the first brake B 1 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and the first shaft TM 1 is connected with the fourth shaft TM 4 by the operation of the third clutch C 3 . In this state, the input torque is input to the first shaft TM 1 .

In addition, the sixth shaft TM 6 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward second speed D 2 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward third speed D 3 , the first and second clutch C 1 and C 2 and the first brake B 1 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and the second shaft TM 2 is connected with the input shaft IS by the operation of the second clutch C 2 . In this state, an input torque is input to the first shaft TM 1 .

In addition, the sixth shaft TM 6 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward third speed D 3 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward fourth speed D 4 , the first clutch C 1 and the first and second brakes B 1 and B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and an input torque is input to the first shaft TM 1 .

In such a state, the sixth and seventh shafts TM 6 and TM 7 act as fixed elements by the operation of the first and second brakes B 1 and B 2 , thereby realizing the forward fourth speed D 4 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward fifth speed D 5 , the first and fourth clutches C 1 and C 4 and the first brake B 1 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and the second shaft TM 2 is connected with the seventh shaft TM 7 by the operation of the fourth clutch C 4 . In this state, an input torque is input to the first shaft TM 1 .

In addition, the sixth shaft TM 6 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the forward fifth speed D 5 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward sixth speed D 6 , the first and fourth clutches C 1 and C 4 and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and the second shaft TM 2 is connected with the seventh shaft TM 7 by the operation of the fourth clutch C 4 . In this state, an input torque is input to the first shaft TM 1 .

In addition, the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward sixth speed D 6 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward seventh speed D 7 , the first, third, and fourth clutches C 1 , C 3 , and C 4 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , the first shaft TM 1 is connected with the fourth shaft TM 4 by the operation of the third clutch C 3 , and the second shaft TM 2 is connected with the seventh shaft TM 7 by the operation of the fourth clutch C 4 .

In this arrangement, the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 integrally rotate, and a torque is input to the first shaft TM 1 , thereby realizing the forward seventh speed D 7 , where a torque is output as inputted, and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward eighth speed D 8 , the first and third clutches C 1 and C 3 and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and first shaft TM 1 is connected with the fourth shaft TM 4 by the operation of the third clutch C 3 . In this state, the input torque is input to the first shaft TM 1 .

In addition, the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward eighth speed D 8 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward ninth speed D 9 , the first and second clutch C 1 and C 2 and the second brake B 2 are simultaneously operated.

As a result, the first shaft TM 1 is connected with the input shaft IS by the operation of the first clutch C 1 , and the second shaft TM 2 is connected with the input shaft IS by the operation of the second clutch C 2 . In this state, a torque is input to the first and second shafts TM 1 and TM 2 .

In addition, the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward ninth speed D 9 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the forward tenth speed D 10 , the second and third clutches C 2 and C 3 and the second brake B 2 are simultaneously operated.

As a result, the second shaft TM 2 is connected with the input shaft IS by the operation of the second clutch C 2 , and first shaft TM 1 is connected with the fourth shaft TM 4 by the operation of the third clutch C 3 . In this state, the input torque is input to the second shaft TM 2 .

In addition, the seventh shaft TM 7 acts as a fixed element by the operation of the second brake B 2 , thereby realizing the forward tenth speed D 10 and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

In this embodiment, in the reverse speed REV, the second and fourth clutches C 2 and C 4 and the first brake B 1 are simultaneously operated.

As a result, the second shaft TM 2 is connected with the input shaft IS by the operation of the second clutch C 2 , and the second shaft TM 2 is connected with the seventh shaft TM 7 by the operation of the fourth clutch C 4 . In this state, a torque is input to the second shaft TM 2 .

In addition, the sixth shaft TM 6 acts as a fixed element by the operation of the first brake B 1 , thereby realizing the reverse speed REV and outputting a shifted torque to the output shaft OS connected with the third shaft TM 3 .

As described above, a planetary gear train according to one embodiment of the present disclosure may realize ten forward speeds and one reverse speed by operating the four planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 and by controlling the four clutches C 1 , C 2 , C 3 , and C 4 and the two brakes B 1 and B 2 .

In addition, a planetary gear train according to an embodiment of the present disclosure may substantially improve driving stability by realizing shift-stages appropriate for rotation speeds of an engine due to multi-stages of an automatic transmission.

In addition, a planetary gear train according to an embodiment of the present disclosure may maximize engine driving efficiency by multi-stages of an automatic transmission. The disclosed planetary gear train may also improve power delivery performance and fuel consumption.

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