JP5373740B2 - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress friction loss of an automatic transmission which shifts the rotation of an input shaft to a plurality of stages through a plurality of planetary gear mechanisms arranged in a transmission case to be output from an output member. <P>SOLUTION: This automatic transmission includes four planetary gear mechanisms PGS1-PGS4, three clutches C1-C3, and three brakes B1-B3. The two third and fourth planetary gear mechanisms constitute four first to fourth rotational elements Y1-Y4. A first element Sa, a sixth element Rb, a third element Ra, and the third rotational element Y3 are connected to a fourth element Sb, a first rotational element Y1, an input shaft 2 and an output member 3, respectively. The first clutch C1, the second clutch C2 and the third clutch C3 are structured to freely connect the third element Ra, the second element Ca, and a first connection body Sa-Sb to the second rotational element Y2, a second connection body Rb-Y1 and the third element Ra, respectively. The first brake B1, the second brake B2 and the third brake B3 are structured to freely fix a fifth element Cb, the first connection body Sa-Sb and the fourth rotational element Y4 to a transmission case 1, respectively. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an automatic transmission in which rotation of an input shaft is shifted to a plurality of stages via a plurality of planetary gear mechanisms arranged in a transmission case and output from an output member.

  Conventionally, an automatic operation capable of performing eight forward gears using the first planetary gear mechanism for input, the second and third planetary gear mechanisms for shifting, and the six engaging mechanisms. A transmission is known (see, for example, Patent Document 1).

  In Patent Document 1, a planetary gear mechanism for input includes a first sun gear and a first ring gear, a pair of first pinions that mesh with each other and one meshes with the first sun gear and the other meshes with the first ring gear. So-called double pinion type planetary gear mechanism comprising a first carrier that pivotally and revolves freely (when the carrier is fixed, the sun gear and the ring gear rotate in the same direction, so the plus planetary gear mechanism or the positive planetary gear mechanism Incidentally, when the ring gear is fixed, the sun gear and the carrier rotate in different directions.

  The first planetary gear mechanism decelerates the rotational speed of a fixed element in which a first sun gear is fixed to a transmission case, an input element in which a first carrier is connected to an input shaft, and a first carrier in which a first ring gear is an input element. Output element.

  In addition, the two planetary gear mechanisms for shifting are engaged with the second sun gear, the third sun gear, and the second ring gear integrated with the third ring gear, and one of them meshes with the second sun gear and the second ring gear. The other is a Ravigneaux type planetary gear mechanism comprising a second carrier that pivotally supports and revolves a pair of second pinions meshing with the third sun gear.

  This Ravigneaux type planetary gear mechanism includes a first rotation element, a second rotation element, and a second rotation element in order with an interval corresponding to the gear ratio in a collinear diagram (a figure in which the ratio of relative speeds of the rotation elements can be represented by a straight line). When the rotating element, the third rotating element, and the fourth rotating element are used, the first rotating element is the second sun gear, the second rotating element is the second carrier integrated with the third carrier, and the third rotating element is the third ring gear. The integrated second ring gear and fourth rotation element become the third sun gear.

  In addition, as an engagement mechanism, a first wet multi-plate clutch that releasably connects a first ring gear that is an output element of the first planetary gear mechanism and a fourth rotation element that is a third sun gear, an input shaft, and a second carrier And a second wet multi-plate clutch for releasably connecting a first rotary element comprising a first ring gear and a second sun gear as output elements. A fourth wet multi-plate clutch for releasably connecting the first carrier as the input element and the first rotating element comprising the second sun gear, and the first rotating element comprising the second sun gear to be disengageable to the transmission case. A first brake for fixing, and a second brake for releasably fixing the second rotating element including the second carrier to the transmission case.

  According to the above configuration, the first speed is established by engaging the first wet multi-plate clutch and the second brake, and the second speed is established by engaging the first wet multi-plate clutch and the first brake. A stage is established, and a third speed stage is established by engaging the first wet multi-plate clutch and the third wet multi-plate clutch, and the first wet multi-plate clutch and the fourth wet multi-plate clutch are engaged. This establishes the fourth gear.

  Further, the fifth speed stage is established by engaging the first wet multi-plate clutch and the second wet multi-plate clutch, and 6 by engaging the second wet multi-plate clutch and the fourth wet multi-plate clutch. By establishing the first gear, engaging the second wet multi-plate clutch and the third wet multi-plate clutch, the seventh gear is established, and by engaging the second wet multi-plate clutch and the first brake. The eighth gear is established.

  In addition, the conventional automatic transmission forms eight rows on the axis of the input shaft. Specifically, in order from the torque converter side, the first row is the fourth clutch and the first brake, the second row is the first planetary gear mechanism, the third row is the first clutch, and the fourth row is the third clutch (the second clutch). The three clutches appear to be in the same row as the first planetary gear mechanism on the skeleton diagram, but in reality, the third clutch piston and the oil passage are formed between the first clutch and the output gear. ), The fifth row is the output gear, the sixth row is the second planetary gear mechanism, the seventh row is the third planetary gear mechanism, and the eighth row is the second clutch and second brake.

JP 2005-273768 A

  In the above-described conventional example, the number of engagement mechanisms engaged at each shift stage is two. Therefore, the friction loss due to dragging of the remaining four engagement mechanisms that are open increases, resulting in a problem that the efficiency of the automatic transmission deteriorates.

  An object of the present invention is to provide an automatic transmission which can reduce friction loss in view of the above points.

  [1] In order to achieve the above object, the present invention includes an input shaft that is rotatably supported in a transmission case and rotated by power from a drive source, and the rotation of the input shaft is performed in a plurality of stages. An automatic transmission that shifts and outputs from an output member is provided with first to fourth planetary gear mechanisms each including three elements including a sun gear, a carrier, and a ring gear, and the first planetary gear mechanism The second planetary gear mechanism has three elements as a first element, a second element, and a third element, respectively, in the order of arrangement at intervals corresponding to the gear ratio in the collinear chart in which the relative rotational speed ratio can be represented by a straight line. Are the fourth element, the fifth element, and the sixth element, respectively, in the order of arrangement at intervals corresponding to the gear ratio in the nomograph, and the elements of the third and fourth planetary gear mechanisms are Comprising four rotating elements, The four rotating elements are respectively designated as a first rotating element, a second rotating element, a third rotating element, and a fourth rotating element in order of arrangement in the collinear chart in which the relative rotational speed ratio of the rotating elements can be represented by a straight line. The first element and the fourth element are connected to form a first connecting body, the sixth element and the first rotating element are connected to form a second connecting body, and the third element Is connected to the input shaft, and the third rotating element is connected to the output member.

  A first clutch capable of coupling the third element and the second rotating element; a second clutch capable of coupling the second element and the second coupling body; and a first clutch of the first planetary gear mechanism. A third clutch capable of connecting any two of the first to third elements; a first brake capable of fixing the fifth element to the transmission case; and There are six engagement mechanisms comprising a second brake that can be fixed to the machine case and a third brake that can fix the fourth rotating element to the transmission case, and at least three of the six engagement mechanisms. Each shift stage is established by setting one engagement mechanism to a connected state or a fixed state.

  According to the present invention, as will be apparent from the description of the embodiment described later, three engagement mechanisms are engaged and connected in each shift stage among a total of six engagement mechanisms of three clutches and three brakes. Or it will be in a fixed state. Therefore, the number of engagement mechanisms that are not connected and fixed in each gear stage is released is three, and the number of engagement mechanisms that are released in each gear stage is less than that in the conventional case where four engagement mechanisms are opened. The friction loss due to the engaging mechanism can be reduced, and the transmission efficiency of the automatic transmission can be improved.

  [2] In the present invention, the sixth element is a ring gear of the second planetary gear mechanism, the first rotating element is configured to include at least the sun gear of the fourth planetary gear mechanism, and the fourth planetary gear mechanism is used as the second planetary gear mechanism. It is preferable to arrange the sun gear of the fourth planetary gear mechanism integrally with the ring gear of the second planetary gear mechanism by disposing the gear mechanism radially outward.

  According to this configuration, since the fourth planetary gear mechanism is disposed radially outward of the second planetary gear mechanism, the axial length of the automatic transmission can be shortened.

  [3] In the present invention, it is preferable to provide a one-way clutch that allows forward rotation of the fourth rotating element and prevents reverse rotation. According to this, the friction loss can be further reduced, and the shift controllability between the shift stages can be improved.

  [4] In the present invention, it is preferable that the third brake is constituted by a meshing mechanism. According to this, friction loss can be further reduced.

  [5] In the present invention, without providing the above-described 1-way clutch, the third brake is fixed in a state in which the fourth rotating element is fixed to the transmission case, and the fourth rotating element is allowed to rotate forward and reverse. You may comprise with the 2 way clutch switchable to the reverse rotation prevention state to prevent. This can also reduce the friction loss and improve the shift controllability between the shift stages.

  [6] In the present invention, it is preferable that the second clutch is constituted by a meshing mechanism. According to this, friction loss can be further reduced.

  [7] In the present invention, the first to fourth planetary gear mechanisms are so-called single pinions comprising a sun gear, a ring gear, and a carrier that rotatably and revolves a pinion that meshes with the sun gear and the ring gear. Type planetary gear mechanism (when the carrier is fixed, the sun gear and the ring gear rotate in different directions, so it is also called a minus planetary gear mechanism or a negative planetary gear mechanism. Incidentally, when the ring gear is fixed, the sun gear and the carrier And rotate in the same direction.).

  According to this, the planetary gear mechanism is a so-called double gear comprising a sun gear, a ring gear, and a carrier that rotatably supports and rotates a pair of pinions that mesh with each other and one meshes with the sun gear and the other meshes with the ring gear. Pinion type planetary gear mechanism (Since the sun gear and the ring gear rotate in the same direction when the carrier is fixed, it is also called the plus planetary gear mechanism or the positive planetary gear mechanism. Incidentally, when the ring gear is fixed, the sun gear and the carrier are different from each other. Compared with the case where the power is transmitted from the input shaft to the output member, the number of places where the gear meshes can be reduced and the transmission efficiency can be further improved. it can.

  [8] In the present invention, a start clutch that can transmit the power of the drive source to the input shaft may be provided.

  [9] In the present invention, the power of the drive source can be transmitted to the input shaft via the torque converter.

The skeleton figure which shows the upper half of the automatic transmission of embodiment of this invention. The collinear diagram which shows ratio of the relative speed of each element of the 1st-4th planetary gear mechanism of the automatic transmission of embodiment. (A) is explanatory drawing which shows the state of each engagement mechanism in every gear stage of the automatic transmission of embodiment. (B) is explanatory drawing which shows an example of the gear ratio of each gear stage of embodiment. (C) is explanatory drawing which shows an example of the common ratio between each gear stage of embodiment. (D) is explanatory drawing which shows an example of the gear ratio of each planetary gear mechanism of embodiment, and the reciprocal orange of an automatic transmission. Sectional drawing which shows an example of the 2 way clutch as a 3rd brake.

  FIG. 1 shows an embodiment of an automatic transmission according to the present invention. In the automatic transmission according to the present embodiment, a driving force output from a driving source ENG such as an internal combustion engine (engine) (not shown) that is rotatably supported in the transmission case 1 has a lockup clutch LC and a damper DA. An input shaft 2 transmitted via the torque converter TC and an output member 3 composed of an output gear arranged concentrically with the input shaft 2 are provided. The rotation of the output member 3 is transmitted to the left and right drive wheels of the vehicle via a differential gear and a propeller shaft (not shown). Instead of the torque converter TC, a single-plate or multi-plate start clutch configured to be frictionally engageable may be provided.

  In the transmission case 1, first to fourth planetary gear mechanisms PGS 1 to 4 are arranged concentrically with the input shaft 2.

  The first planetary gear mechanism PGS1 is a so-called single pinion type planetary gear mechanism (comprising a sun gear Sa, a ring gear Ra, and a carrier Ca that rotatably and revolves a pinion Pa meshing with the sun gear Sa and the ring gear Ra). When the carrier is fixed, the sun gear and the ring gear rotate in different directions, so it is also called a negative planetary gear mechanism or a negative planetary gear mechanism.When the ring gear is fixed, the sun gear and the carrier rotate in the same direction. .).

  Referring to the collinear diagram of the first planetary gear mechanism PGS1 shown in the upper part of FIG. 2 (a diagram in which the ratio of the relative rotational speeds of the three elements of the sun gear, the carrier, and the ring gear can be represented by a straight line (speed line)) The three elements Sa, Ca, Ra of the first planetary gear mechanism PGS1 are arranged from the left side in the order in which they are arranged at intervals corresponding to the gear ratio (number of teeth of the ring gear / number of teeth of the sun gear) in the alignment chart. Assuming two elements and a third element, the first element is the sun gear Sa, the second element is the carrier Ca, and the third element is the ring gear Ra.

  Here, the ratio between the distance between the sun gear Sa and the carrier Ca and the distance between the carrier Ca and the ring gear Ra is set to h: 1, where h is the gear ratio of the first planetary gear mechanism PGS1. In the alignment chart, the lower horizontal line and the upper horizontal line indicate that the rotational speeds are “0” and “1” (the same rotational speed as the input shaft 2), respectively.

  The second planetary gear mechanism PGS2 is also configured by a so-called single pinion type planetary gear mechanism that includes a sun gear Sb, a ring gear Rb, and a carrier Cb that rotatably and revolves a pinion Pb that meshes with the sun gear Sb and the ring gear Rb. Is done.

  Referring to the collinear diagram of the second planetary gear mechanism PGS2 shown in the middle stage of FIG. 2, the three elements Sb, Cb, Rb of the second planetary gear mechanism PGS2 are arranged at intervals corresponding to the gear ratio in the collinear diagram. If the fourth element, the fifth element, and the sixth element are respectively arranged from the left in the order of arrangement, the fourth element is the sun gear Sb, the fifth element is the carrier Cb, and the sixth element is the ring gear Rb. The ratio between the distance between the sun gear Sb and the carrier Cb and the distance between the carrier Cb and the ring gear Rb is set to i: 1, where i is the gear ratio of the second planetary gear mechanism PGS2.

  The third planetary gear mechanism PGS3 is also configured by a so-called single pinion type planetary gear mechanism that includes a sun gear Sc, a ring gear Rc, and a carrier Cc that rotatably and revolves a pinion Pc that meshes with the sun gear Sc and the ring gear Rc. Is done.

  The fourth planetary gear mechanism PGS4 is also a so-called single-pinion type planetary gear mechanism that includes a sun gear Sd, a ring gear Rd, and a carrier Cd that rotatably and revolves a pinion Pd that meshes with the sun gear Sd and the ring gear Rd. Consists of.

  The third planetary gear mechanism PGS3 and the fourth planetary gear mechanism PGS4 are configured to convert any two of the three elements including the sun gear Sc, the carrier Cc, and the ring gear Rc of the third planetary gear mechanism PGS3 into the fourth planetary gear mechanism PGS4. By connecting to any two of the three elements consisting of the sun gear Sd, the carrier Cd, and the ring gear Rd, four rotating elements are formed.

  Referring to the collinear diagram of the third planetary gear mechanism PGS3 and the fourth planetary gear mechanism PGS4 shown in the lower part of FIG. 2, the respective rotating elements are arranged in order from the left, the first rotating element Y1, the second rotating element Y2, the third Assuming that the rotation element Y3 and the fourth rotation element Y4 are used, the first rotation element Y1 is obtained by connecting the sun gear Sc of the third planetary gear mechanism PGS3 and the sun gear Sd of the fourth planetary gear mechanism PGS4, and the second rotation element Y2 is the second rotation element Y2. The carrier Cc of the third planetary gear mechanism PGS3, the third rotating element Y3 is obtained by connecting the ring gear Rc of the third planetary gear mechanism PGS3 and the carrier Cd of the fourth planetary gear mechanism PGS4, and the fourth rotating element Y4 is the fourth planetary gear. It becomes the ring gear Rd of the mechanism PGS4.

  In the collinear diagram of the third planetary gear mechanism PGS3 and the fourth planetary gear mechanism PGS4, the lower horizontal line indicates that the rotational speed is “0”, and the upper horizontal line indicates that the rotational speed indicates the rotation of the input shaft. “1” indicates the same “1”.

  When the gear ratio of the third planetary gear mechanism PGS3 (the number of teeth of the ring gear / the number of teeth of the sun gear) is j and the gear ratio of the fourth planetary gear mechanism PGS4 is k, the distance between the first to fourth rotating elements is , J: 1: (j + 1) / k.

  The first gear Sa-Sb is configured by connecting the sun gear Sa (first element) of the first planetary gear mechanism PGS1 and the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2. Further, the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2 and the first rotating element Y1 are connected to form a second connecting body Rb-Y1. The ring gear Ra (third element) of the first planetary gear mechanism PGS <b> 1 is connected to the input shaft 2. The third rotating element Y3 is coupled to the output member 3 that is an output gear.

  Further, the automatic transmission according to the present embodiment includes first to third three clutches C1 to C3 and first to third brakes B1 to B3 as engagement mechanisms. The first clutch C1 is a friction engagement type wet multi-plate clutch, and connects the ring gear Ra (third element) and the second rotating element Y2 of the first planetary gear mechanism PGS1 and disconnects the connection. It is configured to be switchable to an open state.

  The second clutch C2 is a meshing mechanism including a dog clutch or a synchromesh mechanism having a synchronization function, and a coupling state in which the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second coupling body Rb-Y1 are coupled. And an open state in which this connection is cut off. The second clutch C2 may be a friction engagement type wet multi-plate clutch. The third clutch C3 is a friction engagement type wet multi-plate clutch, and a connection state in which the first coupling body Sa-Sb and the ring gear Ra (third element) of the first planetary gear mechanism PGS1 are coupled, and this coupling. It is configured to be switchable to an open state that cuts off.

  The first brake B1 is a friction engagement type wet multi-plate brake. The first brake B1 is a fixed state in which the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 is fixed to the transmission case 1, and an open state that releases this fixing. It is configured to be switchable between states. The second brake B2 is a friction engagement type wet multi-plate brake, and is configured to be switchable between a fixed state in which the first connecting body Sa-Sb is fixed to the transmission case 1 and an open state in which the fixing is released. Has been.

  The third brake B3 is a meshing mechanism including a dog clutch or a synchromesh mechanism having a synchronization function, and can be switched between a fixed state in which the fourth rotating element Y4 is fixed to the transmission case 1 and an open state in which this fixing is released. It is configured. Further, in the automatic transmission according to the present embodiment, a 1-way clutch F1 is provided that is arranged side by side with the third brake B3, allows forward rotation of the fourth rotating element Y4, and prevents reverse rotation. The third brake B3 may be a friction engagement type wet multi-plate brake.

  The states of the clutches C1 to C3 and the brakes B1 to B3 are switched by a transmission control unit (not shown) based on vehicle information such as the traveling speed of the vehicle.

  The fourth planetary gear mechanism PGS4 is disposed radially outward of the second planetary gear mechanism PGS2. The ring gear Rb (sixth element) of the second planetary gear mechanism PGS2 and the sun gear Sd of the fourth planetary gear mechanism PGS4 are integrally connected. Since the fourth planetary gear mechanism PGS4 and the fourth planetary gear mechanism PGS4 overlap each other in the radial direction by disposing the fourth planetary gear mechanism PGS4 radially outward of the second planetary gear mechanism PGS2, as described above, The shaft length of the transmission can be shortened.

  The second planetary gear mechanism PGS2 and the fourth planetary gear mechanism PGS4 only have to overlap at least partially in the radial direction, and this can reduce the axial length, but both are completely in diameter. If they overlap in the direction, the axial length can be shortened the most.

  On the axis of the input shaft 2, from the drive source ENG and the torque converter TC side, the third clutch C3, the first planetary gear mechanism PGS1, the second clutch C2, the first clutch C1, the third planetary gear mechanism PGS3, the output gear The output member 3, the second planetary gear mechanism PGS2, and the second brake B2 are arranged in this order. The first brake B1 is disposed radially outward of the second brake B2, and the third brake B3 and 1-way clutch F1 are fourth planetary gears disposed radially outward of the second planetary gear mechanism PGS2. It is arranged radially outward of the mechanism PGS4.

  As a result, all of the first to third brakes B1 to B3 are arranged in the end portion in the axial direction of the input shaft 2 in the transmission case 1, and the planetary gear mechanism and the clutch are not easily obstructed. Thus, the degree of freedom in designing the brake oil passage is improved.

  The transmission case 1 is provided with a side wall 1a that is positioned between the output member 3 and the second planetary gear mechanism PGS2 and extends radially inward. The side wall 1 a is provided with a cylindrical portion 1 b that extends inward in the radial direction of the output member 3. The output member 3 is pivotally supported by the cylindrical portion 1b via a bearing. By configuring in this way, the output member 3 can be firmly supported by the cylindrical portion 1b having high mechanical strength connected to the transmission case 1.

  Next, with reference to FIG. 2 and FIG. 3, the case where each gear stage of the automatic transmission of this embodiment is established is demonstrated.

  When establishing the first gear, the second clutch C2 is set in a connected state, and the first brake B1 is set in a fixed state. By setting the second clutch C2 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second connected body Rb-Y1 rotate at the same speed. Further, by setting the first brake B1 in the fixed state, the rotation speed of the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 becomes “0”. The rotational speed of the fourth rotating element Y4 becomes “0” by the action of the one-way clutch F1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “1st” shown in FIG. 2, and the first gear is established.

  At the first speed, since the third brake B3 is in the released state, the number of engagement mechanisms released is “4”, but the rotation speed of the fourth rotating element Y4 is “0” due to the action of the one-way clutch F1. Therefore, no friction loss occurs in the third brake B3. Therefore, the substantial number of releases in the first gear is “3”. Further, if the third brake B3 is also fixed at the first speed, the engine brake can be applied.

  When establishing the second gear, the second clutch C2 is set in a connected state, and the second brake B2 is set in a fixed state. By setting the second clutch C2 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second connected body Rb-Y1 rotate at the same speed. Moreover, the rotation speed of 1st coupling body Sa-Sb will be set to "0" by making 2nd brake B2 into a fixed state. The rotational speed of the fourth rotating element Y4 becomes “0” by the action of the one-way clutch F1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “2nd” shown in FIG. 2, and the second speed stage is established.

  At the second speed, since the third brake B3 is in the released state, the number of engagement mechanisms released is “4”, but the rotation speed of the fourth rotating element Y4 is “0” due to the action of the one-way clutch F1. Therefore, no friction loss occurs in the third brake B3. Therefore, the substantial number of releases at the second gear is "3". Further, if the third brake B3 is also fixed at the second speed, the engine brake can be applied.

  When establishing the third gear, the second clutch C2 and the third clutch C3 are brought into a connected state. By setting the third clutch C3 in the connected state, the first planetary gear mechanism PGS1 is in a locked state in which the first to third elements Sa, Ca, Ra cannot be relatively rotated, and the first to third The rotational speeds of the three elements Sa, Ca and Ra are “1”. Further, by setting the second clutch C2 in the connected state, the rotational speed of the second coupling body Rb-Y1 becomes “1” which is the same speed as the carrier Ca (second element) of the first planetary gear mechanism PGS1. The rotational speed of the fourth rotating element Y4 becomes “0” by the action of the one-way clutch F1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “3rd” shown in FIG. 2, and the third speed stage is established.

  At the third speed, since the third brake B3 is in the released state, the number of engagement mechanisms released is “4”, but the rotation speed of the fourth rotating element Y4 is “0” due to the action of the one-way clutch F1. Therefore, no friction loss occurs in the third brake B3. Accordingly, the substantial number of releases at the third gear is "3". Further, if the third brake B3 is also fixed at the third speed, the engine brake can be applied.

  In order to establish the fourth speed, the first clutch C1 and the second clutch C2 are connected. By setting the first clutch C1 in the connected state, the ring gear Ra (third element) of the first planetary gear mechanism PGS1 and the second rotating element Y2 rotate at the same speed. Further, by setting the second clutch C2 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second connected body Rb-Y1 rotate at the same speed. The rotational speed of the fourth rotating element Y4 becomes “0” by the action of the one-way clutch F1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “4th” shown in FIG. 2, and the fourth speed stage is established.

  At the fourth speed, since the third brake B3 is in the released state, the number of disengagement of the engagement mechanism is “4”, but the rotation speed of the fourth rotating element Y4 is “0” by the action of the one-way clutch F1. Therefore, no friction loss occurs in the third brake B3. Therefore, the substantial number of releases at the fourth gear is “3”. Further, if the third brake B3 is also fixed at the fourth speed, the engine brake can be applied.

  When establishing the fifth gear, the first clutch C1, the second clutch C2, and the third clutch C3 are brought into a connected state. By setting the third clutch C3 in the connected state, the first planetary gear mechanism PGS1 is in a locked state in which the first to third elements Sa, Ca, Ra cannot be relatively rotated, and the first to third The rotational speeds of the three elements Sa, Ca and Ra are “1”. Further, by setting the second clutch C2 in the connected state, the rotational speed of the second coupling body Rb-Y1 becomes “1” which is the same speed as the carrier Ca (second element) of the first planetary gear mechanism PGS1.

  Further, by setting the first clutch C1 in the connected state, the second rotating element Y2 rotates at “1” which is the same speed as the rotating speed of the ring gear Ra (third element) of the first planetary gear mechanism PGS1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “5th”, which is “1”, and the fifth speed stage is established.

  When the sixth speed is established, the first clutch C1 and the second clutch C2 are connected and the second brake B2 is fixed. By setting the second brake B2 in a fixed state, the rotation speed of the first coupling body Sa-Sb becomes “0”. Further, by setting the second clutch C2 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second connected body Rb-Y1 rotate at the same speed. Further, by setting the first clutch C1 in the connected state, the second rotating element Y2 rotates at “1” which is the same speed as the rotating speed of the ring gear Ra (third element) of the first planetary gear mechanism PGS1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “6th” shown in FIG. 2, and the sixth speed stage is established.

  When establishing the seventh speed, the first clutch C1 and the second clutch C2 are connected and the first brake B1 is fixed. By setting the first brake B1 in the fixed state, the rotation speed of the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the second clutch C2 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the second connected body Rb-Y1 rotate at the same speed.

  Further, by setting the first clutch C1 in the connected state, the second rotating element Y2 rotates at “1” which is the same speed as the rotating speed of the ring gear Ra (third element) of the first planetary gear mechanism PGS1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “7th” shown in FIG. 2, and the seventh speed stage is established.

  When establishing the eighth gear, the first clutch C1 is set in a connected state, and the first brake B1 and the second brake B2 are set in a fixed state. By setting the first brake B1 and the second brake B2 in a fixed state, the rotational speeds of the sun gear Sb (fourth element) and the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 are both “0”. Thus, the second planetary gear mechanism PGS2 enters a locked state in which the fourth to sixth elements Sb, Cb, and Rb cannot be rotated relative to each other, and the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2 rotates. The speed, that is, the rotational speed of the second connector Rb-Y1 is also “0”.

  Further, by setting the first clutch C1 in the connected state, the second rotating element Y2 rotates at “1” which is the same speed as the rotating speed of the ring gear Ra (third element) of the first planetary gear mechanism PGS1. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “8th” shown in FIG. 2, and the eighth speed stage is established.

  In order to establish the reverse gear, the third clutch C3 is brought into a connected state, and the first brake B1 and the third brake B3 are brought into a fixed state. By setting the first brake B1 in the fixed state, the rotation speed of the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the third brake B3 in a fixed state, the rotation speed of the fourth rotation element Y4 becomes “0”.

  Moreover, the rotational speed of 1st coupling body Sa-Sb will be "1" by making the 3rd clutch C3 into a connection state. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “Rvs” in the reverse rotation (rotation in the direction in which the vehicle moves backward) shown in FIG. 2, and the reverse gear is established.

  A speed line indicated by a dotted line in FIG. 2 represents that each element of the other planetary gear mechanisms rotates (idle) following the planetary gear mechanism that transmits power among the four planetary gear mechanisms PGS1 to PGS4. ing.

  FIG. 3A is a diagram summarizing and displaying the states of the clutches C1 to C3, the brakes B1 to B3, and the one-way clutch F1 in each of the above-described shift speeds, in the columns of the clutches C1 to C3 and the brakes B1 to B3. “◯” indicates a connected state or a fixed state, and a blank indicates an open state. Further, “◯” in the row of the 1-way clutch F1 indicates a state in which the rotation speed of the fourth rotating element Y4 becomes “0” by the action of the 1-way clutch F1. Further, “(◯)” in the column of the third brake B3 indicates that the connection state is established when the engine brake is applied.

  3B, the gear ratio h of the first planetary gear mechanism PGS1 is 2.236, and the gear ratio i of the second planetary gear mechanism PGS2 is 1.700, as shown in FIG. The gear ratio (the rotational speed of the input shaft 2 / the speed of the output member 3) when the gear ratio j of the third planetary gear mechanism PGS3 is 1.603 and the gear ratio k of the fourth planetary gear mechanism PGS4 is 1.371. Rotation speed). According to this, as shown in FIG. 3 (c), the common ratio (ratio of gear ratios between the respective gears) becomes appropriate, and the ratio orange (gear ratio / first gear) shown in FIG. The gear ratio of the 8th gear is also appropriate.

  According to the automatic transmission of the present embodiment, it is possible to perform eight forward speeds and one reverse speed. Further, at each shift stage, the number of wet multi-plate clutches and wet multi-plate brakes to be released is three or less, so that friction loss can be suppressed and driving force transmission efficiency can be improved.

  In addition, the 7th speed is a predetermined medium speed, the 1st speed to the 7th speed that is the predetermined medium speed, and the 8th speed that exceeds the 7th speed that is the predetermined medium speed is the high speed. By definition, in the high speed range as the 8th speed exceeding the 7th speed which is the predetermined medium speed, the second clutch C2 configured with a meshing mechanism with less friction loss than the wet multi-plate clutch is opened. It becomes a state.

  Further, the third brake B3 that is released from the fifth gear to the eighth gear is also constituted by a meshing mechanism. Therefore, in the high speed range, the number of wet multi-plate clutches and wet multi-plate brakes to be released is 1, and the friction loss when the vehicle is traveling at high speed can be reduced to improve the fuel efficiency.

  Further, the second clutch C2 composed of the meshing mechanism is only switched between the connected state and the released state between the seventh and eighth speeds which are predetermined medium speed stages. Since the transmission torque (transmission driving force) in the second clutch C2 at the seventh speed (predetermined medium speed) is relatively small, even if the second clutch C2 is constituted by a dog clutch as a meshing mechanism, It is possible to smoothly switch between the fixed state and the open state at the time of shifting between the eighth speeds.

  Further, since all the planetary gear mechanisms PGS1 to PGS4 are constituted by so-called single pinion type planetary gear mechanisms, they are on the transmission path of the driving force as compared with those constituted by so-called double pinion type planetary gear mechanisms. The number of gear engagements can be reduced, and transmission efficiency can be improved.

  In addition, since the 1-way clutch F1 is provided together with the third brake B3, it is not necessary to switch the state of the third brake B3 when shifting between the 4th speed stage and the 5th speed stage, and the shift controllability is improved. The

  In the present embodiment, the second clutch C2 and the third brake B3 are configured by the meshing mechanism. However, even if both are configured by the wet multi-plate clutch and the wet multi-plate brake, each speed stage It is possible to obtain the effect of the present invention that the number of opened wet multi-plate clutches and wet multi-plate brakes can be suppressed to 3 or less, and friction loss can be suppressed.

  The 1-way clutch F1 may be omitted. In this case, when the first to fourth gears are established, the third brake B3 may be fixed. Further, when the 1-way clutch F1 is omitted, the third brake B3 is fixed in a state where the fourth rotating element Y4 is fixed to the transmission case 1, and the forward rotation of the fourth rotating element Y4 is allowed and the reverse rotation is prevented. You may comprise with the 2 way clutch switchable to a reverse rotation prevention state. An example of the two-way clutch will be specifically described with reference to FIG.

  The two-way clutch TW as the third brake B3 in FIG. 4 is arranged with an inner ring TW1 connected to the fourth rotating element Y4 and a radially outer side of the inner ring TW1, and a transmission case. 1 is provided with an outer ring TW2 connected to 1, and a holding ring TW3 disposed between the inner ring TW1 and the outer ring TW2.

  A plurality of cam surfaces TW1a are formed on the outer peripheral surface of the inner ring TW1. The retaining ring TW3 is provided with a plurality of cutout holes TW3a corresponding to the cam surface TW1a. A roller TW4 is accommodated in the cutout hole TW3a. The two-way clutch TW includes first and second electromagnetic clutches not shown. The first electromagnetic clutch is configured to connect the outer ring TW2 and the holding ring TW3 when energized. When the first electromagnetic clutch is not energized, the holding ring TW3 is configured to be rotatable relative to the inner ring TW1 and the outer ring TW2.

  Further, as shown in FIG. 4A, the diameter of the roller TW4 is such that when the roller TW4 is present at the center of the cam surface TW1a, a gap A is opened, and as shown in FIGS. 4B and 4C, When the roller TW4 is at the end of the cam surface TW1a, the roller TW4 is set to contact the inner ring TW1 and the outer ring TW2.

  When the first electromagnetic clutch is not energized, the holding ring TW3 can freely rotate, so that the roller TW4 continues to be positioned at the center of the cam surface TW1a as shown in FIG. Can do. Accordingly, the two-way clutch TW is in a state in which the inner ring TW1 can freely rotate.

  When the first electromagnetic clutch is energized, the holding ring TW3 is fixed to the transmission case 1 via the outer ring TW2. In this case, regardless of whether the inner ring TW1 is rotated forward or backward, the holding ring TW3 is fixed as shown in FIGS. 4B and 4C, so that the roller TW4 is positioned on the cam surface TW1a. It will be located at the end.

  At this time, the roller TW4 is sandwiched between the cam surface TW1a and the inner peripheral surface of the outer ring TW2, and the rotation of the inner ring TW1 is prevented. That is, the two-way clutch TW is in a fixed state.

  The second electromagnetic clutch has a first state in which the retaining ring TW3 is coupled to the inner ring TW1 in a state where the notch hole TW3a is located at one end of the cam surface TW1a as shown in FIG. As shown in (c), the second state in which the retaining ring TW3 is coupled to the inner ring TW1 with the notch hole TW3a positioned at the other end of the cam surface TW1a, and the coupling between the retaining ring TW3 and the inner ring TW1 It is configured to be switchable to an open state that cuts off.

  Assuming that the clockwise direction in FIG. 4 is the reverse direction, the two-way clutch TW disconnects the outer ring TW2 and the holding ring TW3 from the first electromagnetic clutch when the first electromagnetic clutch is not energized (energization off state). 2 When the electromagnetic clutch is in the first state, the reverse rotation prevention state is established.

  When the third brake B3 is configured by such a 2-way clutch TW, the 2-way clutch TW is fixed from the first forward speed to the fourth speed and the reverse speed, and from the fifth forward speed to the eighth speed stage. Can be established by setting the reverse rotation prevention state.

  If the third brake B3 is configured by the two-way clutch TW described above, unlike the case where the third brake B3 is configured by a friction engagement type brake, friction loss does not occur in the third brake B3. Accordingly, as in the case where the third brake B3 is configured by the meshing mechanism, the friction loss can be suppressed as the whole automatic transmission.

  In addition, when traveling at the fourth speed, when an upshift to the fifth speed is predicted based on the vehicle information such as the traveling speed, the transmission control unit (not shown) serves as the third brake B3. It is preferable to switch the 2-way clutch TW to the reverse rotation prevention state in advance.

  According to this, similarly to the effect of the 1-way clutch F1, when upshifting from the 4th gear to the 5th gear, the switching of the state of the 2 way clutch TW as the third brake B3 is completed. Since the shift to the fifth speed can be achieved simply by engaging the three clutch C3, the upshift from the fourth speed to the fifth speed can be performed smoothly, and the shift controllability of the automatic transmission is improved.

  According to the two-way clutch TW configured as described above, in addition to the above-described fixed state and reverse rotation-prevented state, an open state in which the fixing of the fourth rotating element Y4 to the transmission case 1 is released, The forward rotation of the four-rotating element Y4 can be prevented and the forward rotation can be prevented.

  Specifically, when the first electromagnetic clutch is turned off and the second electromagnetic clutch is released, the two-way clutch TW has a roller TW4 mounted on the cam surface TW1a as shown in FIG. It will be in the state which continues being located in a center part, and will be in the state which can rotate inner ring TW1 freely with respect to outer ring TW2, ie, an open state.

  Further, the first electromagnetic clutch is turned off, and the second electromagnetic clutch is attached to the holding ring TW3 with the notch hole TW3a positioned at the other end of the cam surface TW1a as shown in FIG. 4C. By setting it as the 2nd state connected with TW1, it will be in the state in which normal rotation of inner ring TW1 is blocked | prevented and reverse rotation is permitted, ie, a normal rotation blocking state.

  Accordingly, the above-described second electromagnetic clutch of the two-way clutch TW is omitted, and the two-way clutch TW as the third brake B3 can be switched only between the fixed state and the released state by switching the first electromagnetic clutch. You can also. In this case, each shift speed can be established by switching from the first forward speed to the fourth speed and the reverse speed and switching from the fifth speed to the eighth speed to the open state.

  In addition, the automatic transmission according to the present embodiment can be used to perform nine forward speeds. Specifically, the 9th speed is established by setting the first clutch C1 and the third clutch C3 in the connected state and the first brake B1 in the fixed state. By setting the first brake B1 in the fixed state, the rotation speed of the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 becomes “0”.

  Moreover, the rotational speed of 1st coupling body Sa-Sb will be "1" by making the 3rd clutch C3 into a connection state. Further, by setting the first clutch C1 in the connected state, the second rotating element Y2 rotates at “1” which is the same speed as the rotating speed of the ring gear Ra (third element) of the first planetary gear mechanism PGS1.

  Then, the speed lines of the third planetary gear mechanism PGS3 and the fourth planetary gear mechanism PGS4 become the one-dot chain line shown in FIG. 2, and the rotation of the carrier Cd (11th element) of the fourth planetary gear mechanism PGS4 to which the output member 3 is connected. The speed becomes “9th” shown in FIG. 2, and the ninth gear is established. In this case, the gear ratios h to k of the planetary gear mechanisms PGS1 to PGS4 may be set so that the common ratio and the ratio orange are appropriate.

  In the automatic transmission according to the present embodiment, the third clutch C3 is configured such that the first coupling body Sa-Sb and the ring gear Ra (third element) of the first planetary gear mechanism PGS1 can be coupled. . However, the third clutch of the present invention may be configured such that any two of the first to third elements Sa, Ca, Ra of the first planetary gear mechanism PGS1 are connectable. It is not limited to the configuration. For example, the third clutch C3 may be configured such that the sun gear Sa (first element) of the first planetary gear mechanism PGS1 and the carrier Ca (second element) can be connected, and the carrier Ca (second element). And ring gear Ra (third element) may be configured to be freely connectable.

  Further, in the present embodiment, a description has been given of a gear that performs eight forward shifts, but the automatic transmission of the present invention is not limited to a gear that performs eight forward shifts. For example, the second and sixth speed stages in the embodiment may be omitted, and the forward six speeds may be changed.

DESCRIPTION OF SYMBOLS 1 ... Transmission case, 2 ... Input shaft, 3 ... Output member, ENG ... Drive source, LC ... Lock-up clutch, DA ... Damper, TC ... Torque converter, PGS1 ... First planetary gear mechanism, Sa ... Sun gear (first Element), Ca ... carrier (second element), Ra ... ring gear (third element), Pa ... pinion, PGS2 ... second planetary gear mechanism, Sb ... sun gear (fourth element), Cb ... carrier (fifth element) , Rb ... ring gear (sixth element), Pb ... pinion, PGS3 ... third planetary gear mechanism, Sc ... sun gear, Cc ... carrier, Rc ... ring gear, Pc ... pinion, PGS4 ... fourth planetary gear mechanism, Sd ... sun gear, Cd ... carrier, Rd ... ring gear, Pd ... pinion, C1-C3 ... first to third clutches, B1-B3 ... first to third brakes, F1 ... 1-way clutch, Y1 Y4 ... first to fourth rotating element, TW ... 2-way clutch (third brake).

Claims (9)

An automatic transmission that includes an input shaft that is rotatably supported in a transmission case and that is rotated by power from a drive source, and that rotates the input shaft in multiple stages and outputs the output shaft from an output member. ,
There are provided first to fourth planetary gear mechanisms each having three elements including a sun gear, a carrier, and a ring gear,
The three elements of the first planetary gear mechanism are a first element, a second element, and a third element, respectively, in the order of arrangement at intervals corresponding to the gear ratio in the collinear chart in which the relative rotational speed ratio can be represented by a straight line. ,
The three elements of the second planetary gear mechanism are a fourth element, a fifth element, and a sixth element, respectively, in order of arrangement at intervals corresponding to the gear ratio in the collinear diagram,
Each element of the third and fourth planetary gear mechanisms constitutes four rotating elements, and the relative rotational speed ratio of the four rotating elements can be represented by a straight line in the arrangement order in the collinear diagram, Four rotating elements from one side as a first rotating element, a second rotating element, a third rotating element and a fourth rotating element, respectively,
The first element and the fourth element are connected to form a first connecting body, the sixth element and the first rotating element are connected to form a second connecting body, and the third element is Connected to the input shaft, the third rotating element is connected to the output member,
A first clutch capable of connecting the third element and the second rotating element;
A second clutch capable of connecting the second element and the second connector;
A third clutch capable of connecting any two of the first to third elements of the first planetary gear mechanism;
A first brake capable of fixing the fifth element to the transmission case;
A second brake capable of fixing the first connector to the transmission case;
Six engagement mechanisms comprising a third brake that can fix the fourth rotating element to the transmission case;
An automatic transmission characterized in that each gear stage is established by bringing at least three of the six engagement mechanisms into a connected state or a fixed state. The automatic transmission according to claim 1, wherein
The sixth element is a ring gear of the second planetary gear mechanism;
The first rotating element includes at least a sun gear of the fourth planetary gear mechanism,
The fourth planetary gear mechanism is disposed radially outward of the second planetary gear mechanism;
A sun gear of the fourth planetary gear mechanism is configured integrally with a ring gear of the second planetary gear mechanism. The automatic transmission according to claim 1 or 2,
An automatic transmission comprising a one-way clutch that allows forward rotation of the fourth rotating element and prevents reverse rotation. The automatic transmission according to any one of claims 1 to 3,
The automatic transmission is characterized in that the third brake is constituted by a meshing mechanism. The automatic transmission according to claim 1 or 2,
The third brake is a two-way clutch that can be switched between a fixed state in which the fourth rotating element is fixed to the transmission case and a reverse rotation preventing state in which the fourth rotating element is allowed to rotate forward and is prevented from rotating backward. An automatic transmission characterized by comprising. The automatic transmission according to any one of claims 1 to 5,
The automatic transmission is characterized in that the second clutch is constituted by a meshing mechanism. The automatic transmission according to any one of claims 1 to 6,
The first to fourth planetary gear mechanisms are constituted by a single pinion type planetary gear mechanism that includes a sun gear, a ring gear, and a carrier that rotatably and revolves a pinion that meshes with the sun gear and the ring gear. An automatic transmission characterized by that. The automatic transmission according to any one of claims 1 to 7,
2. An automatic transmission comprising a starting clutch capable of transmitting power of the driving source to the input shaft. The automatic transmission according to any one of claims 1 to 7,
The automatic transmission is characterized in that the power of the drive source is transmitted to the input shaft via a torque converter.

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