JP5373748B2 - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrict a friction loss of an automatic transmission in which rotation of an input shaft is changed in a multistage via a plurality of planetary gear mechanisms disposed in a transmission case to output it from an output member. <P>SOLUTION: The automatic transmission includes: the four planetary gear mechanisms PGS1 to PGS4; three clutches C1 to C3; and three brakes B1 to B3. Each element of the third and the fourth planetary gear mechanisms PGS3 and PGS4 constitutes four rotation elements Y1 to Y4. The third element Sa and the input shaft 2, the third rotation element Y3 and the output member 3, the first element Ra and the fifth element Cb, and the sixth element Rb and the second rotation element Y2 are connected respectively. The first clutch C1 freely connects the third element Sa and the first connection Ra-Cb, the second clutch C2 freely connects the third element Sa and the fourth element Sb, and the third clutch C3 freely connects the second element Ca and the fourth element Y4 respectively. The first brake B1 freely fixes the first connection Ra-Cb, the second brake B2 freely fixes the fourth element Sb, and the third brake B3 freely fixes the first rotation element Y1 to the 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 rotational elements are arranged in the order of arrangement at intervals corresponding to the gear ratio in the collinear chart in which the relative rotational speed ratio of the rolling elements can be represented by a straight line. As the rotation element and the fourth rotation element, the third element is connected to the input shaft, the third rotation element is connected to the output member, and the first element and the fifth element are connected to each other. A coupling body is configured, and the second coupling body is configured by coupling the sixth element and the second rotating element, and the first coupling body and the third element can be coupled freely as an engagement mechanism. 1 clutch, a second clutch capable of coupling the third element and the fourth element, a third clutch capable of coupling the second element and the fourth rotating element, and the first coupling body A first brake which can be fixed to a transmission case, and the fourth element connected to the transmission. A second brake that can be fixed to the transmission case, and a third brake that can fix the first rotating element to the transmission case, and the first to third clutches and the first to third clutches. Each shift stage is established by bringing at least three engagement mechanisms out of a total of six engagement mechanisms of the three brakes into a connected state or a fixed state.

  According to the present invention, as will be apparent from the description of the embodiments described later, among the total of six engagement mechanisms of three clutches and three brakes, three engagement mechanisms are engaged and connected at each shift stage. State or 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 second rotating element includes at least the sun gear of the third planetary gear mechanism, and the third planetary gear mechanism is the second planetary gear mechanism. It is preferable to arrange the sun gear of the third planetary gear mechanism integrally with the ring gear of the second planetary gear mechanism by disposing the planetary gear mechanism radially outward.

  According to this configuration, since the third planetary gear mechanism is arranged radially outward of the second planetary gear mechanism, the axial length of the automatic transmission can be shortened, and the vehicle (particularly the FF type vehicle) ) Can be improved.

  [3] In the present invention, the second brake is disposed radially outward of the second clutch, the first brake is disposed radially outward of the third brake, and the third clutch is disposed on the first planetary gear mechanism. It is preferable to arrange it radially outward. According to this, the axial length of the automatic transmission can be further shortened.

  [4] In the present invention, the first to fourth planetary gear mechanisms include a sun gear, a ring gear, and a so-called single pinion that supports a sun gear and a pinion that meshes with the ring gear so as to rotate and revolve freely. 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.

  [5] In the present invention, it is preferable that the first brake includes a one-way clutch that allows forward rotation of the first coupling body 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.

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

  [7] In the present invention, the first brake can be switched between a fixed state in which the first connecting body is fixed to the transmission case and a reverse rotation preventing state in which the first connecting body is allowed to rotate forward and prevents reverse rotation. A two-way clutch may be used. This also can reduce the friction loss and improve the shift controllability.

  [8] In the present invention, it is preferable that the third clutch is constituted by a meshing mechanism. This also can reduce the friction loss.

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

  [10] 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 1st Embodiment of this invention. The alignment chart which shows ratio of the relative speed of each element of the 1st-4th planetary gear mechanism of the automatic transmission of 1st Embodiment. Explanatory drawing which shows the state of each engagement mechanism in every gear stage of the automatic transmission of 1st Embodiment. Sectional drawing which shows an example of a 2 way clutch. The skeleton figure which shows the upper half of the automatic transmission of 2nd Embodiment of this invention.

[First Embodiment]
FIG. 1 shows a first embodiment of an automatic transmission according to the present invention. In the automatic transmission according to the first embodiment, the driving force output by a driving source ENG such as an internal combustion engine (engine) (not shown) that is rotatably supported in the transmission case 1 is generated by the lockup clutch LC and the damper DA. The input shaft 2 is transmitted via a torque converter TC having an output shaft, and the output member 3 is an output gear 3 arranged concentrically with the input shaft 2. 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 a ring gear Ra, the second element is a carrier Ca, and the third element is a sun gear Sa.

  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 PG1. 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 arranged such that any two of the three elements including the sun gear, ring gear, and carrier of the third planetary gear mechanism PGS3 are replaced with the sun gear of the fourth planetary gear mechanism PGS4, By connecting to any two of the three elements including the ring gear and the carrier, four rotating elements are configured.

  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 If the rotation element Y3 and the fourth rotation element Y4 are used, the first rotation element Y1 is the sun gear Sd of the fourth planetary gear mechanism PGS4, and the second rotation element Y2 is the sun gear Sc of the third planetary gear mechanism PGS3 and the fourth planetary gear mechanism PGS4. Of the third planetary gear mechanism PGS3 and the ring gear Rd of the fourth planetary gear mechanism PGS4, and the fourth rotating element Y4 is the third planetary gear. It becomes the ring gear Rc of the mechanism PGS3.

  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 , Jk: j: 1.

  A sun gear Sa (third element) of the first planetary gear mechanism PGS <b> 1 is connected to the input shaft 2. The third rotating element Y3 including the carrier Cc of the third planetary gear mechanism PGS3 and the ring gear Rd of the fourth planetary gear mechanism PGS4 is connected to the output member 3 serving as an output gear.

  Further, the ring gear Ra (first element) of the first planetary gear mechanism PGS1 and the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 are connected to constitute a first connected body Ra-Cb. Further, the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2 and the second rotating element Y2 are connected to constitute a second connecting body Rb-Y2.

  The automatic transmission according to the first embodiment includes first to third clutches C1 to C3 and first to third brakes B1 to B3 as engagement mechanisms.

  The first clutch C1 is a wet multi-plate clutch, and a connected state in which the sun gear Sa (third element) of the first planetary gear mechanism PGS1 and the first connected body Ra-Cb are connected, and an open state in which this connection is cut off. It is configured to be switchable.

  The second clutch C2 is a wet multi-plate clutch, and a connected state that connects the sun gear Sa (third element) of the first planetary gear mechanism PGS1 and the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2, It is configured to be switchable to an open state in which this connection is broken.

  The third clutch C3 is a meshing mechanism including a dog clutch or a synchromesh mechanism having a synchronization function, and a coupling state coupling the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the fourth rotating element Y4, It is configured to be switchable to an open state in which this connection is broken. The third clutch C3 may be a wet multi-plate clutch.

  The first brake B1 is a meshing mechanism including a dog clutch or a synchromesh mechanism having a synchronization function. The first brake B1 is in a fixed state in which the first coupling body Ra-Cb is fixed to the transmission case 1 and in an open state in which this fixing is released. It is configured to be switchable. The first brake B1 may be a wet multi-plate brake.

  Further, the first brake B1 includes a 1-way clutch F1 that allows normal rotation of the first coupling body Ra-Cb and prevents reverse rotation.

  The second brake B2 is a wet multi-plate brake and can be switched between a fixed state in which the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 is fixed to the transmission case 1 and an open state in which this fixing is released. It is configured.

  The third brake B3 is a wet multi-plate brake, and is configured to be switchable between a fixed state in which the first rotating element Y1 is fixed to the transmission case 1 and an open state in which this fixing is released.

  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.

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

  As a result, all of the first to third brakes B1 to B3 are arranged at the shaft end portion of the input shaft 2, and the planetary gear mechanism and the clutch are not easily obstructed. Design freedom is improved.

  The third planetary gear mechanism PGS3 is disposed radially outward of the second planetary gear mechanism PGS2. The ring gear Rb of the second planetary gear mechanism PGS2 and the sun gear Sc of the third planetary gear mechanism PGS3 are integrally connected to constitute a part of the second coupling body Rb-Y2. Since the third planetary gear mechanism PGS3 and the third planetary gear mechanism PGS3 overlap in the radial direction by disposing the third planetary gear mechanism PGS3 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 third planetary gear mechanism PGS3 only have to overlap at least partly in the radial direction, and this can shorten the axial length. If they overlap in the direction, the axial length can be shortened the most.

  The transmission case 1 is provided with a side wall 1a that is positioned between the output member 3 and the third brake B3 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 1st Embodiment is established is demonstrated.

  When establishing the first gear, the third clutch C3 is engaged and the second brake B2 is fixed. The rotational speed of the first coupling body Ra-Cb becomes “0” by the action of the one-way clutch F1. By setting the third clutch C3 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the first rotating element Y1 rotate at the same speed. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, since 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”, the three elements Sb, Cb, Rb enters a locked state where relative rotation is impossible, and the rotational speed of the second coupling body Rb-Y2 including the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2 also becomes “0”. 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 first brake B1 is in the released state, the number of disengagement of the engagement mechanism is “4”, but the rotation speed of the first coupling body Ra-Cb is increased by the action of the one-way clutch F1. Since it is “0”, no friction loss occurs in the first brake B1. Therefore, the substantial number of releases in the first gear is “3”. Further, if the first brake B1 is also fixed at the first speed, the engine brake can be applied.

  When establishing the second gear, the third clutch C3 is in a connected state, and the third brake B3 is in a fixed state. By setting the third clutch C3 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the fourth rotating element Y4 rotate at the same speed. Further, by setting the third brake B3 in a fixed state, the rotation speed of the first rotation element Y1 becomes “0”. Further, the rotation speed of the first coupling body Ra-Cb 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 first brake B1 is in the released state, the number of disengagement of the engagement mechanism is “4”, but the rotation speed of the first coupling body Ra-Cb is increased by the action of the one-way clutch F1. Since it is “0”, no friction loss occurs in the first brake B1. Therefore, the substantial number of releases at the second gear is "3". Further, if the first brake B1 is also fixed at the second speed, the engine brake can be applied.

  When establishing the third gear, the third clutch C3 is set in a connected state, and the second brake B2 and the third brake B3 are set in a fixed state. By setting the third clutch C3 in the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the fourth rotating element Y4 rotate at the same speed. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sb (fourth 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 first rotation element Y1 becomes “0”. 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.

  When establishing the fourth speed, the second clutch C2 and the third clutch C3 are connected and the third brake B3 is fixed. By bringing the second clutch C2 into the connected state, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 is the same as the rotational speed of the sun gear Sa (third element) of the first planetary gear mechanism PGS1. “1”. Further, by bringing the third clutch C3 into the connected state, the carrier Ca (second element) of the first planetary gear mechanism PGS1 and the fourth rotating element Y4 rotate at the same speed. Further, by setting the third brake B3 in a fixed state, the rotation speed of the first rotation element Y1 becomes “0”. 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.

  When establishing the fifth gear, the first clutch C1 and the third clutch C3 are connected and the third brake B3 is fixed. By setting the first clutch C1 in the connected state, the first connected body Ra-Cb rotates at “1” at the same speed as the sun gear Sa (third element) of the first planetary gear mechanism PGS1. As a result, the sun gear Sa (third element) and the ring gear Ra (first element) of the first planetary gear mechanism PGS1 rotate at “1” at the same speed, and the first to first gears of the first planetary gear mechanism PGS1. The three elements Sa, Ca, Ra of No. 3 are in a locked state where relative rotation is impossible, and the rotation speed of the carrier Ca (second element) of the first planetary gear mechanism PGS1 becomes “1”. Further, by bringing the third clutch C3 into the connected state, the rotational speed of the fourth rotating element Y4 becomes “1”, which is the same speed as the carrier Ca (second element) of the first planetary gear mechanism PGS1. Further, by setting the third brake B3 in a fixed state, the rotation speed of the first rotation element Y1 becomes “0”. Then, the rotation speed of the third rotation element Y3 to which the output member 3 is connected becomes “5th” shown in FIG. 2, and the fifth speed stage is established.

  When establishing the sixth gear, the first to third clutches C1 to C3 are brought into a connected state. By setting the first clutch C1 in the connected state, the first connected body Ra-Cb rotates at “1” at the same speed as the sun gear Sa (third element) of the first planetary gear mechanism PGS1. As a result, the sun gear Sa (third element) and the ring gear Ra (first element) of the first planetary gear mechanism PGS1 rotate at “1” at the same speed, and the first to first gears of the first planetary gear mechanism PGS1. The three elements Sa, Ca, Ra of No. 3 are in a locked state where relative rotation is impossible, and the rotation speed of the carrier Ca (second element) of the first planetary gear mechanism PGS1 becomes “1”. Further, by bringing the third clutch C3 into the connected state, the rotational speed of the fourth rotating element Y4 becomes “1”, which is the same speed as the carrier Ca (second element) of the first planetary gear mechanism PGS1.

  Further, by setting the second clutch C2 in the connected state, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 is made equal to the rotational speed of the sun gear Sa (third element) of the first planetary gear mechanism PGS1. It becomes the same “1”. Accordingly, the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 and the carrier Cb (fifth element) rotate at the same speed “1”, and the fourth to sixth of the second planetary gear mechanism PGS2 are rotated. The three elements Sb, Cb, Rb of the second planetary gear mechanism PGS2 are locked so that the relative rotation is impossible, and the rotational speed of the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2, that is, the second coupling body Rb-Y2, is “1”. It becomes.

  Further, the third planetary gear mechanism PGS3 has a rotational speed between the sun gear Sc of the third planetary gear mechanism PGS3 included in the second rotating element Y2 and the ring gear Rc of the third planetary gear mechanism PGS3 constituting the fourth rotating element Y4. Becomes the same speed “1”, the three elements Sc, Cc, Rc are locked so as not to rotate relative to each other, and the rotational speed of the carrier Cc of the third planetary gear mechanism PGS3, that is, the output member 3 is connected. The rotation speed of the third rotation element Y3 becomes “1”, and the sixth speed is established.

  When establishing the seventh gear, the first clutch C1 and the second clutch C2 are connected, and the third brake B3 is fixed. By setting the first clutch C1 in the connected state, the first connected body Ra-Cb rotates at “1” at the same speed as the sun gear Sa (third element) of the first planetary gear mechanism PGS1. Further, by setting the second clutch C2 in the connected state, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 is made equal to the rotational speed of the sun gear Sa (third element) of the first planetary gear mechanism PGS1. It becomes the same “1”.

  Accordingly, the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 and the carrier Cb (fifth element) rotate at the same speed “1”, and the fourth to sixth of the second planetary gear mechanism PGS2 are rotated. The three elements Sb, Cb, Rb of the second planetary gear mechanism PGS2 are locked so that the relative rotation is impossible, and the rotational speed of the ring gear Rb (sixth element) of the second planetary gear mechanism PGS2, that is, the second coupling body Rb-Y2, is “1”. It becomes. Further, by setting the third brake B3 in a fixed state, the rotation speed of the first rotation element Y1 becomes “0”. 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 speed, the first clutch C1 is set in the connected state, and the second brake B2 and the third brake B3 are set in the fixed state. By setting the first clutch C1 in the connected state, the first connected body Ra-Cb rotates at “1” at the same speed as the sun gear Sa (third element) of the first planetary gear mechanism PGS1. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sb (fourth 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 first rotation element Y1 becomes “0”. 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 second clutch C2 is set in a connected state, and the first brake B1 and the third brake B3 are set in a fixed state. By bringing the second clutch C2 into the connected state, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism PGS2 is the same as the rotational speed of the sun gear Sa (third element) of the first planetary gear mechanism PGS1. “1”. Further, by setting the first brake B1 in a fixed state, the rotation speed of the first coupling body Ra-Cb becomes “0”. Further, by setting the third brake B3 in a fixed state, the rotation speed of the first rotation element Y1 becomes “0”. 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. 3 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 at each of the above-described shift stages, and “◯” in the column 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 carrier Cb (fifth element) of the second planetary gear mechanism PGS2 becomes “0” by the action of the 1-way clutch F1. Further, “(◯)” in the column of the first brake B1 indicates that the engine brake is fixed when the engine brake is applied.

  3 shows that the gear ratio h of the first planetary gear mechanism PGS1 is 1.659, the gear ratio i of the second planetary gear mechanism PGS2 is 3.997, and the gear ratio j of the third planetary gear mechanism PGS3 is 1. 370, and the gear ratio (rotational speed of the input shaft 2 / rotational speed of the output member 3) when the gear ratio k of the fourth planetary gear mechanism PGS4 is 3.287 are also shown.

  According to the automatic transmission of the first embodiment, eight forward speeds can be changed. 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.

  Also, the 6th speed is a predetermined medium speed, the first speed to the 6th speed that is a predetermined medium speed, the low speed range, and the 7th speed to the 8th speed that exceeds the 6th speed that is a predetermined medium speed. Is defined as the high speed range, and in the high speed range from the 7th speed to the 8th speed exceeding the 6th speed, which is the predetermined medium speed, the meshing mechanism has less friction loss than the wet multi-plate clutch. The configured third clutch C3 is in the released state.

  Further, the first brake B1 that is opened at all the gear speeds except the first gear, the second gear, and the reverse 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 third clutch C3 including the meshing mechanism is only switched between a connected state and an opened state between the sixth and seventh speeds, which are predetermined medium speed stages. Since the transmission torque (transmission driving force) in the third clutch C3 at the sixth speed (predetermined medium speed) is relatively small, even if the third clutch C3 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 seventh speed.

  Further, since all the planetary gear mechanisms PGS1 to PGS4 are constituted by so-called single pinion type planetary gear mechanisms, the sun gear and the ring gear mesh with each other, one meshes with the first sun gear, and the other meshes with the first ring gear. A so-called double pinion type planetary gear mechanism comprising a first carrier that rotatably supports and revolves a pair of meshing first pinions (when the carrier is fixed, the sun gear and the ring gear rotate in the same direction. This is also referred to as a gear mechanism or a positive planetary gear mechanism.By the way, when the ring gear is fixed, the sun gear and the carrier rotate in different directions.) Can be reduced, and transmission efficiency can be improved.

  In addition, since the 1-way clutch F1 is provided together with the first brake B1, it is not necessary to switch the state of the first brake B1 when shifting between the second speed and the third speed, and the shift controllability is improved. The

  Further, the automatic transmission according to the first embodiment configures first to seventh rows on the axis of the input shaft 2 in order from the torque converter side. Specifically, the first row is the second clutch C2 and the second brake B2, the second row is the first brake B1 and the third brake B3, the third row is the output member 3, and the fourth row is the fourth planetary gear mechanism. PGS4, the fifth row is the second planetary gear mechanism PGS2 and the third planetary gear mechanism PGS3, the sixth row is the first clutch C1, and the seventh row is the first planetary gear mechanism PGS1 and the third clutch C3. For this reason, the axial length of the automatic transmission can be shortened as compared with the conventional eight rows.

  In the first embodiment, the third clutch C3 and the first brake B1 are configured by the meshing mechanism. However, even if both are configured by the wet multi-plate clutch and the wet multi-plate brake, The effect of the present invention can be obtained in 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.

  Further, the 1-way clutch F1 of the first embodiment may be omitted. In this case, when establishing the first gear and the second gear, the first brake B1 may be set in a fixed state.

  When the 1-way clutch F1 is omitted, the first brake B1 is fixed in a state in which the first coupling body Ra-Cb is fixed to the transmission case 1, and the first coupling body Ra-Cb is allowed to rotate forward and reverse. It may be configured by a two-way clutch that can be switched to a reverse rotation preventing state that prevents the reverse rotation. An example of the two-way clutch will be specifically described with reference to FIG.

  The two-way clutch TW as the first brake B1 in FIG. 4 is disposed at a distance from the inner ring TW1 coupled to the first coupling body Ra-Cb and radially outward of the inner ring TW1 and is changed in speed. An outer ring TW2 connected to the machine case 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. Is possible.

  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 first brake B1 is configured by such a 2-way clutch TW, the 2-way clutch TW is fixed at the first forward speed, the second speed and the reverse speed, and from the third forward speed to the eighth speed stage. Can be established by setting the reverse rotation prevention state. If the transmission control unit (not shown) predicts an upshift to the third gear based on vehicle information such as the running speed while the vehicle is traveling at the second gear, the 2-way clutch TW is reversed in advance. It is preferable to switch to the blocking state.

  According to this, when upshifting from the second gear to the third gear, the two-way clutch TW has already been switched to the reverse rotation prevention state, so that only the second brake B2 is fixed and the third gear is shifted from the second gear to the third gear. Upshifting to a high gear can be performed, and shifting can be performed smoothly, and the shift controllability of the automatic transmission is improved.

  Further, if the first brake B1 is configured by the above-described 2-way clutch, unlike the case where the first brake B1 is configured by a friction engagement type brake, no friction loss occurs in the first brake B1. Accordingly, as in the case where the first brake B1 is configured by the meshing mechanism, the friction loss can be suppressed as the whole automatic transmission.

  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 first coupling body Ra-Cb is fixed to the transmission case 1 is released. The first connecting body Ra-Cb can be configured to be switchable to a forward rotation blocking state in which the forward rotation is prevented and the reverse rotation is allowed.

  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.

  Therefore, the above-described second electromagnetic clutch of the two-way clutch TW is omitted, and the two-way clutch TW as the first brake B1 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 stage can be established by setting the first speed stage, the second speed stage, and the reverse speed stage to a fixed state and switching from the third speed stage to the eighth speed stage.

  In the automatic transmission according to the first embodiment, for example, the first and eighth speed stages may be omitted and the forward sixth speed may be changed.

[Second Embodiment]
The automatic transmission according to the second embodiment of the present invention will be described with reference to FIG. In the automatic transmission of the second embodiment, the third planetary gear mechanism PGS3 is not disposed radially outward of the second planetary gear mechanism PGS2, and a damper DA and a starting clutch C0 are provided instead of the torque converter. The third clutch C <b> 3 and the first brake B <b> 1 are configured by a wet multi-plate clutch, and the output member 3 is configured by an output shaft disposed on the same axis as the input shaft 2.

  Then, on the axis of the input shaft 2, from the start clutch C0 side, the second clutch C2, the second planetary gear mechanism PGS2, the first clutch C1, the first planetary gear mechanism PGS1, the third clutch C3, and the third planetary gear mechanism. PGS3, fourth planetary gear mechanism PGS4, and third brake B3 are arranged in this order. The second brake B2 is disposed radially outward of the second clutch C2, and the first brake B1 is disposed radially outward of the second planetary gear mechanism PGS2.

  In the automatic transmission according to the second embodiment, the third rotating element Y3 to which the output member 3 serving as the output shaft is coupled is configured only by the carrier Cc of the third planetary gear mechanism PGS3, and the fourth rotating element Y4 is the second rotating element Y4. The ring gear Rc of the three planetary gear mechanism PGS3 and the ring gear Rd of the fourth planetary gear mechanism PGS4 are connected. Other configurations are the same as those in the first embodiment, and each shift stage can be established in the same manner as in the first embodiment. Further, if only the gear ratio k of the fourth planetary gear mechanism PGS4 is changed from 3.287 of the first embodiment to 1.900, the gear ratios of the respective speed stages of the second embodiment are also shown in FIG. It becomes the same as the gear ratio.

  Even with the automatic transmission of the second embodiment, it is possible to perform eight forward shifts, and to reduce the number of open wet multi-plate clutches and wet multi-plate brakes at each shift step to three or less, to reduce friction loss, The transmission efficiency of the driving force can be improved.

  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 first brake B1, it is not necessary to switch the state of the first brake B1 when shifting between the second speed and the third speed, and the shift controllability is improved. The

  In the second embodiment as well, as in the first embodiment, the third clutch C3 and the first brake B1 may be configured by a meshing mechanism. According to this, the effect by the meshing mechanism described in the first embodiment can also be obtained in the second embodiment.

  Also in the second embodiment, the one-way clutch may be omitted as in the first embodiment. In this case, as described in the first embodiment, the first brake B1 can be configured by a two-way clutch.

  Further, the automatic transmission according to the second embodiment can also be configured to shift forward 6th gear while omitting the first gear and the eighth gear, for example.

  In the automatic transmission according to the second embodiment, a torque converter TC may be used instead of the starting clutch C0 as in the first embodiment.

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 (3rd Element), Ca ... carrier (second element), Ra ... ring gear (first 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, Y1-Y4 ... first to fourth rotating elements, C1-C3 ... first to third clutches, B1-B3 ... first to third braces , F1 ... 1-way clutch, TW ... 2-way clutch (first brake).

Claims (10)

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 corresponds to the gear ratio in the collinear chart in which the four rotation elements constitute four rotation elements and the relative rotation speed ratio of the four rotation elements can be represented by a straight line. The four rotation elements are arranged as a first rotation element, a second rotation element, a third rotation element, and a fourth rotation element from one side, respectively, in the arrangement order at intervals of
The third element is coupled to the input shaft, the third rotating element is coupled to the output member, the first element and the fifth element are coupled to form a first coupled body, and the sixth A second connecting body is configured by connecting the element and the second rotating element;
As an engagement mechanism,
A first clutch capable of connecting the first connector and the third element;
A second clutch capable of connecting the third element and the fourth element;
A third clutch capable of connecting the second element and the fourth rotating element;
A first brake capable of fixing the first connector to the transmission case;
A second brake capable of fixing the fourth element to the transmission case;
A third brake capable of fixing the first rotating element to the transmission case;
By bringing at least three engagement mechanisms out of a total of six engagement mechanisms of the first to third clutches and the first to third brakes into a connected state or a fixed state, An automatic transmission characterized by establishing a gear position. The automatic transmission according to claim 1, wherein
The sixth element is a ring gear of the second planetary gear mechanism;
The second rotating element includes at least a sun gear of the third planetary gear mechanism,
The third planetary gear mechanism is disposed radially outward of the second planetary gear mechanism;
The automatic transmission according to claim 3, wherein a sun gear of the third planetary gear mechanism is integrally formed with a ring gear of the second planetary gear mechanism. The automatic transmission according to claim 2, wherein
The second brake is disposed radially outward of the second clutch;
The first brake is disposed radially outward of the third brake;
The automatic transmission is characterized in that the third clutch is disposed radially outward of the first planetary gear mechanism. The automatic transmission according to any one of claims 1 to 3,
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 4,
The automatic transmission according to claim 1, wherein the first brake includes a one-way clutch that allows forward rotation of the first connecting body and prevents reverse rotation. The automatic transmission according to any one of claims 1 to 5,
The automatic transmission is characterized in that the first brake is constituted by a meshing mechanism. The automatic transmission according to any one of claims 1 to 4,
The first brake is a two-way clutch that can be switched between a fixed state in which the first connecting body is fixed to the transmission case and a reverse rotation preventing state in which the first connecting body is allowed to rotate forward and prevent reverse rotation. An automatic transmission characterized by comprising. The automatic transmission according to any one of claims 1 to 7,
The automatic transmission is characterized in that the third clutch is constituted by a meshing mechanism. The automatic transmission according to any one of claims 1 to 8,
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 8,
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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