JP6204843B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission that shifts the rotation of an input unit to a plurality of stages via a plurality of planetary gear mechanisms and outputs it from an output unit.

  2. Description of the Related Art Conventionally, there is known an automatic transmission configured to be capable of shifting eight forward speeds and one reverse speed using four planetary gear mechanisms and six engagement mechanisms including clutches and brakes (for example, patents). Reference 1).

  The automatic transmission of Patent Document 1 includes an input shaft that is rotatably supported in a housing, and an output unit that includes an output gear disposed concentrically with the input shaft. The rotation of the output unit is transmitted to the left and right drive wheels of the vehicle via a differential gear or a propeller shaft.

  Within the housing, first to fourth planetary gear mechanisms are arranged concentrically with the input shaft. The first planetary gear mechanism is composed of three elements: a first sun gear, a first ring gear, and a first carrier that pivotally supports a first pinion meshing with the first sun gear and the first ring gear so as to rotate and revolve. A so-called single pinion type planetary gear mechanism (when the carrier is fixed and the sun gear is rotated, the ring gear rotates in a direction different from that of the sun gear, so it is also referred to as a negative planetary gear mechanism or a negative planetary gear mechanism. When the sun gear is rotated, the carrier rotates in the same direction as the sun gear.).

  The three elements of the first planetary gear mechanism are shown in a collinear diagram of the first planetary gear mechanism (the ratio of the relative rotational speeds of the three elements of the sun gear, carrier, and ring gear can be represented by a straight line (speed line)). If the first element, the second element, and the third element are arranged from one side in the order of arrangement, the first element is the first sun gear, the second element is the first carrier, and the third element is the first ring gear.

  The second planetary gear mechanism is also a so-called three element including a second sun gear, a second ring gear, and a second carrier that rotatably and revolves a second pinion that meshes with the second sun gear and the second ring gear. It consists of a single pinion type planetary gear mechanism. Assuming that the three elements of the second planetary gear mechanism are the fourth element, the fifth element, and the sixth element from one side in the alignment order of the second planetary gear mechanism, respectively, the fourth element is the second ring gear, The element is the second carrier and the sixth element is the second sun gear.

  The third planetary gear mechanism is also a so-called three element including a third sun gear, a third ring gear, and a third carrier that rotatably and revolves a third pinion that meshes with the third sun gear and the third ring gear. It consists of a single pinion type planetary gear mechanism. Assuming that the three elements of the third planetary gear mechanism are the seventh element, the eighth element, and the ninth element from the one side in the alignment order of the third planetary gear mechanism, respectively, the seventh element is the third sun gear, The element is the third carrier and the ninth element is the third ring gear.

  The fourth planetary gear mechanism is also a so-called three element including a fourth sun gear, a fourth ring gear, and a fourth carrier that pivotally supports a fourth pinion that meshes with the fourth sun gear and the fourth ring gear. It consists of a single pinion type planetary gear mechanism. Assuming that the three elements of the fourth planetary gear mechanism are the tenth element, the eleventh element, and the twelfth element from the one side in the alignment order of the fourth planetary gear mechanism, respectively, the tenth element is the fourth ring gear, The element is the fourth carrier and the twelfth element is the fourth sun gear.

  The first sun gear (first element) of the first planetary gear mechanism is connected to the input shaft. The fourth ring gear (tenth element) of the fourth planetary gear mechanism is connected to the output unit.

  In addition, the first carrier (second element) of the first planetary gear mechanism, the second carrier (fifth element) of the second planetary gear mechanism, and the third ring gear (9th element) of the third planetary gear mechanism are connected. Thus, the first coupling body (second element, fifth element, ninth element) is configured. Further, the first ring gear (third element) of the first planetary gear mechanism and the fourth sun gear (12th element) of the fourth planetary gear mechanism are connected to each other, and the second connected body (third element, twelfth element). Is configured. Further, the third carrier (eighth element) of the third planetary gear mechanism and the fourth carrier (eleventh element) of the fourth planetary gear mechanism are coupled to each other, and the third coupled body (eighth element, eleventh element). Is configured.

  The automatic transmission disclosed in Patent Document 1 includes a total of six engagement mechanisms including first to third clutches and first to third brakes.

  The first clutch is a wet multi-plate clutch, and a connection state connecting the first sun gear (first element) and the third coupling body (eighth element, eleventh element) of the first planetary gear mechanism, and this connection It is configured to be switchable between an open state and a cut state. The second clutch is a wet multi-plate clutch, and a connected state for connecting the first sun gear (first element) of the first planetary gear mechanism and the second ring gear (fourth element) of the second planetary gear mechanism, It is configured to be switchable to an open state where the connection is broken.

  The third clutch is a wet multi-plate clutch, and a connected state connecting the second sun gear (sixth element) and the second connecting body (third element, twelfth element) of the second planetary gear mechanism, and this connection It is configured to be switchable to an open state that cuts off. The first brake is a wet multi-plate brake, and is configured to be switchable between a fixed state in which the third coupling body (eighth element, eleventh element) is fixed to the housing and an open state in which this fixing is released. Yes.

  The second brake is a wet multi-plate brake and is configured to be switchable between a fixed state in which the third sun gear (seventh element) of the third planetary gear mechanism is fixed to the housing and an open state in which this fixing is released. ing. The third brake is a wet multi-plate brake, and is configured to be switchable between a fixed state in which the second sun gear (sixth element) of the second planetary gear mechanism is fixed to the housing and an open state in which this fixing is released. ing.

  In the automatic transmission of Patent Document 1, the first forward speed is established by setting the first brake, the second brake, and the third brake to a fixed state. The second forward speed is established by setting the second brake and the third brake to the fixed state and the third clutch to the connected state. The third forward speed is established by setting the second brake and the third brake to the fixed state and the second clutch to the connected state. The fourth forward speed is established by setting the second brake in a fixed state and the second clutch and the third clutch in a connected state.

  The fifth forward speed is established by setting the second brake in the fixed state and the first clutch and the second clutch in the connected state. By setting the first to third clutches in the connected state, the sixth forward speed is established. The seventh forward speed is established by setting the third brake to a fixed state and connecting the first clutch and the second clutch. The eighth forward speed is established by setting the third brake to a fixed state and connecting the first clutch and the third clutch. The reverse speed is established by setting the first brake and the third brake to the fixed state and the second clutch to the connected state.

JP 2012-97864 A

  In the conventional automatic transmission, it can be considered that the first brake is constituted by a two-way clutch as a switching mechanism. The switching mechanism including the two-way clutch allows, for example, normal rotation (rotation in the same direction as the rotation direction of the input shaft) of the third coupling body (eighth element, eleventh element) and reverse rotation (rotation of the input shaft). It is possible to switch between a reverse rotation preventing state that prevents rotation in the direction opposite to the direction) and a fixed state in which the third coupling body (eighth element, eleventh element) is fixed to the housing.

  When the first brake is configured by such a switching mechanism, the switching mechanism is set in the reverse rotation prevention state when the vehicle is moving forward, and the switching mechanism is set in the fixed state when the vehicle is moving backward. When the shift position is switched from the reverse range to the forward range by the driver's shift operation, the switching mechanism is switched from the fixed state to the reverse rotation prevention state. Conversely, when the shift position is switched from the forward range to the reverse range by the driver's shift operation, the switching mechanism is switched from the reverse rotation prevention state to the fixed state.

  By the way, if the vehicle is switched to the forward range while the vehicle is traveling backward and something in the forward stage is established, the turbine of the torque converter reversely rotates and a high load is input to the torque converter. It is also possible to do.

  In view of the above, it is an object of the present invention to provide an automatic transmission that prevents input of a high load to a torque converter when switching from a reverse range to a forward range and prevents engine stall.

In order to achieve the above object, the present invention provides:
An input unit that is disposed within the housing and through which the power of the drive source is transmitted via a torque converter;
A planetary gear mechanism having a plurality of elements rotatable within the housing;
A plurality of engagement mechanisms switchable to a connected state in which the elements are connected to each other, or switchable to a fixed state in which the elements are fixed to the housing;
An output section;
A shift position detector for detecting the shift position;
An input rotation speed detection unit for detecting the rotation speed of the input unit;
A control unit that receives information on the rotational speed detected from the input rotational speed detection unit and information on the shift position from the shift position detection unit, and controls the engagement mechanism;
An automatic transmission capable of shifting the rotation of the input unit to a plurality of stages and outputting from the output unit,
And forward rotation of the rotation direction the same direction of the input portion, wherein when the rotation of the forward and reverse direction is reversed, allowing the forward rotation of one element of the plurality of said elements, said Comprising a switching mechanism capable of switching between a reverse rotation preventing state for preventing reverse rotation and a fixed state for fixing the element to the housing;
The controller is
When the shift position is in the forward range, the switching mechanism is in the reverse rotation prevention state, and when the shift position is in the reverse range, the switching mechanism is in the fixed state,
When the vehicle is traveling backward and the shift position is switched from the reverse range to the forward range and the vehicle speed is equal to or higher than the first predetermined speed, the input unit can freely rotate and the output unit cannot be rotated. The idle neutral engagement state for controlling the engagement mechanism to be
In the idle neutral engagement state, the switching mechanism is switched from the fixed state to the reverse rotation prevention state when the deceleration of the vehicle is a predetermined value or less.

  According to the automatic transmission of the present invention, when the vehicle speed is switched from the reverse range to the forward range during reverse travel and the vehicle speed is equal to or higher than the first predetermined speed, the input unit can freely rotate and the output unit is prevented from rotating. The engagement mechanism is controlled as described above. This state is defined as an idle neutral engagement state. Thereby, even if the vehicle is traveling in the reverse direction, the reverse rotation of the turbine of the torque converter can be prevented.

  Therefore, according to the present invention, input of a high load to the torque converter when the reverse range is switched to the forward range can be prevented, and engine stall can be prevented.

  In the idle neutral engagement state, the switching mechanism is switched from the fixed state to the reverse rotation prevention state when the deceleration of the vehicle is equal to or less than a predetermined value. Accordingly, it is possible to prevent the switching mechanism from being switched from the fixed state to the reverse rotation preventing state in a state where a relatively large load is applied, the switching mechanism can be switched smoothly, and the first speed can be changed from the idle neutral engagement state. Smooth transition to the in-gear state.

The present invention also provides:
An input unit that is disposed within the housing and through which the power of the drive source is transmitted via a torque converter;
A planetary gear mechanism having a plurality of elements rotatable within the housing;
A plurality of engagement mechanisms switchable to a connected state in which the elements are connected to each other, or switchable to a fixed state in which the elements are fixed to the housing;
An output section;
A shift position detector for detecting the shift position;
An input rotation speed detection unit for detecting the rotation speed of the input unit;
A control unit that receives information on the rotational speed detected from the input rotational speed detection unit and information on the shift position from the shift position detection unit, and controls the engagement mechanism;
An automatic transmission capable of shifting the rotation of the input unit to a plurality of stages and outputting from the output unit,
And forward rotation of the rotation direction the same direction of the input portion, wherein when the rotation of the forward and reverse direction is reversed, allowing the forward rotation of one element of the plurality of said elements, said Comprising a switching mechanism capable of switching between a reverse rotation preventing state for preventing reverse rotation and a fixed state for fixing the element to the housing;
The controller is
When the shift position is in the forward range, the switching mechanism is in the reverse rotation prevention state, and when the shift position is in the reverse range, the switching mechanism is in the fixed state,
When the vehicle is traveling backward and the shift position is switched from the reverse range to the forward range and the vehicle speed is equal to or higher than the first predetermined speed, the input unit can freely rotate and the output unit cannot be rotated. The idle neutral engagement state for controlling the engagement mechanism to be
When the vehicle is traveling in the reverse direction and the shift position is switched from the reverse range to the forward range and the engine brake is applied, the switching mechanism is changed from the fixed state to the reverse rotation preventive state. It is characterized by switching.

  When the engine brake is operating during traveling in the reverse speed, when a switch is made from the fixed state to the reverse rotation preventive state, a load that impedes this switching is not applied. For this reason, as described above, when the engine brake is operating in the reverse speed, the present invention may be configured such that the switching mechanism is switched before the idle neutral engagement state is established.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows typically embodiment of the automatic transmission of this invention. The skeleton figure which shows the automatic transmission of this embodiment. The alignment chart of the planetary gear mechanism of this embodiment. Explanatory drawing which shows the state of the engagement mechanism in each gear stage of the automatic transmission of this embodiment. Explanatory drawing which shows the two-way clutch of this embodiment. The flowchart which shows the process of the control part of this embodiment. Explanatory drawing which shows the transition of the state of the automatic transmission of this embodiment in case a 1st brake is a fixed state. Explanatory drawing which shows the transition of the state of the automatic transmission of this embodiment when a 1st brake is a reverse rotation prevention state. The flowchart which shows the switching process of the 1st brake during idle neutral engagement of this embodiment. The flowchart which shows the process of the control part of other embodiment of the automatic transmission of this invention.

  1 and 2 show an embodiment of the automatic transmission TM of the present invention. In the automatic transmission TM, a driving force output from a driving source ENG such as an internal combustion engine (engine), which is rotatably supported in the housing 1, is transmitted via a torque converter TC having a lockup clutch LC and a damper DA. An input shaft 2 as an input unit and an output unit 3 composed of an output gear arranged concentrically with the input shaft 2 are provided.

  The rotation of the output unit 3 is transmitted to the left and right drive wheels of the vehicle via a differential gear or a propeller shaft (not shown). Instead of the torque converter TC, a single plate type or multi-plate type start clutch configured to be capable of frictional engagement may be provided.

  In the housing 1, first to fourth planetary gear mechanisms PGS1 to PGS4 are disposed concentrically with the input shaft 2. The first planetary gear mechanism PGS1 is a so-called single pinion type planetary gear 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. Mechanism (When the carrier is fixed and the sun gear is rotated, the ring gear rotates in a different direction from the sun gear, so it is also called a negative planetary gear mechanism or a negative planetary gear mechanism. Note that the ring gear is fixed and the sun gear is rotated. And the carrier rotates in the same direction as the sun gear.).

  FIG. 3 shows an alignment chart of the first to fourth planetary gear mechanisms PGS1 to PGS4. In this specification, a collinear diagram is defined as a diagram that can represent the ratio of the relative rotational speeds of the three elements of the sun gear, the carrier, and the ring gear as a straight line (speed line). In the alignment chart, the three elements are arranged at intervals corresponding to the gear ratio (number of teeth of the ring gear / number of teeth of the sun gear).

  Referring to the collinear diagram of the first planetary gear mechanism PGS1 shown in the second stage from the top of FIG. 3, the three elements Sa, Ca, Ra of the first planetary gear mechanism PGS1 are arranged from the left side in the order of alignment of the collinear diagram. Assuming that the first element, the second element, and the third element, respectively, 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 (lines overlapping 4th and 6th) 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 a so-called single pinion type planetary gear mechanism comprising a sun gear Sb, a ring gear Rb, and a carrier Cb that rotatably and revolves the pinion Pb meshing with the sun gear Sb and the ring gear Rb. Consists of.

  Referring to the collinear diagram of the second planetary gear mechanism PGS2 shown in the first stage (uppermost stage) from the top of FIG. 3, the three elements Sb, Cb, Rb of the second planetary gear mechanism PGS2 are 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 ring gear Rb, the fifth element is the carrier Cb, and the sixth element is the sun gear Sb. 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 a so-called single-pinion type planetary gear mechanism that includes a sun gear Sc, a ring gear Rc, and a carrier Cc that pivotally supports the sun gear Sc and the ring gear Rc so as to rotate and revolve. Consists of.

  Referring to the collinear diagram of the third planetary gear mechanism PGS3 shown in the third stage from the top in FIG. 3, the three elements Sc, Cc, Rc of the third planetary gear mechanism PGS3 are arranged from the left side in the alignment order of the collinear diagram. Assuming that the seventh element, the eighth element, and the ninth element are used, the seventh element is the sun gear Sc, the eighth element is the carrier Cc, and the ninth element is the ring gear Rc. The ratio between the distance between the sun gear Sc and the carrier Cc and the distance between the carrier Cc and the ring gear Rc is set to j: 1 where j is the gear ratio of the third planetary gear mechanism PGS3.

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

  Referring to the collinear diagram of the fourth planetary gear mechanism PGS4 shown in the fourth stage (bottom stage) from the top of FIG. 3, the three elements Sd, Cd, Rd of the fourth planetary gear mechanism PGS4 Assuming that the tenth element, the eleventh element, and the twelfth element are arranged in order from the left side, the tenth element is the ring gear Rd, the eleventh element is the carrier Cd, and the twelfth element is the sun gear Sd. The ratio between the distance between the sun gear Sd and the carrier Cd and the distance between the carrier Cd and the ring gear Rd is set to k: 1, where k is the gear ratio of the fourth planetary gear mechanism PGS4.

  The sun gear Sa (first element) of the first planetary gear mechanism PGS <b> 1 is connected to the input shaft 2. Further, the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 is connected to the output unit 3 including an output gear.

  The carrier Ca (second element) of the first planetary gear mechanism PGS1, the carrier Cb (fifth element) of the second planetary gear mechanism PGS2, and the ring gear Rc (9th element) of the third planetary gear mechanism PGS3 are connected. Thus, the first connected body Ca-Cb-Rc is configured. Further, the ring gear Ra (third element) of the first planetary gear mechanism PGS1 and the sun gear Sd (12th element) of the fourth planetary gear mechanism PGS4 are connected to form a second connected body Ra-Sd. . Further, the carrier Cc (eighth element) of the third planetary gear mechanism PGS3 and the carrier Cd (eleventh element) of the fourth planetary gear mechanism PGS4 are coupled to form a third coupled body Cc-Cd.

  Further, the automatic transmission TM of the present embodiment includes one switching mechanism including the first brake B1, the first to third clutches C1 to C3, and the second to fourth brakes B2 to B4. And six engaging mechanisms. The first clutch C1 is a hydraulically actuated wet multi-plate clutch, and is connected to the sun gear Sa (first element) of the first planetary gear mechanism PGS1 and the third connector Cc-Cd. It is configured to be switchable between an open state and a cut state.

  The second clutch C2 is a hydraulically operated wet multi-plate clutch, and connects the sun gear Sa (first element) of the first planetary gear mechanism PGS1 and the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2. It is configured to be switchable between a connected state and an open state in which this connection is broken. The third clutch C3 is a hydraulically-actuated wet multi-plate clutch, and connects the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 and the second connecting body Ra-Sd, and this connection. It is configured to be switchable between an open state and a cut state.

  The first brake B1 is a two-way clutch, and allows the third coupling body Cc-Cd to rotate forward (rotation in the same direction as the rotation direction of the input shaft 2) and prevent reverse rotation, The three linked bodies Cc-Cd are fixed to the housing 1 and can be switched to a fixed state in which the third linked bodies Cc-Cd are prevented from rotating. The second brake B2 is a hydraulically actuated wet type multi-plate brake, and includes a fixed state in which the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 is fixed to the housing 1, and an open state in which this fixing is released. It is configured to be switchable.

  The third brake B3 is a hydraulically actuated wet type multi-plate brake, and includes a fixed state in which the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 is fixed to the housing 1, and an open state in which this fixing is released. It is configured to be switchable. The fourth brake B4 is a hydraulically actuated wet multi-plate brake, and a fixed state in which the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 is fixed to the housing 1 and an open state in which this fixing is released. And can be switched between.

  The states of the clutches C1 to C3 and the brakes B1 to B4 are switched by a control unit ECU (see FIG. 1) including a transmission control unit based on vehicle information such as the vehicle traveling speed.

  On the axis of the input shaft 2, from the drive source ENG and the torque converter TC side, the first clutch C1, the third planetary gear mechanism PGS3, the fourth planetary gear mechanism PGS4, the first planetary gear mechanism PGS1, the third clutch C3, The second planetary gear mechanism PGS2 and the first clutch C1 are arranged in this order.

  The fourth brake B4 is disposed radially outward of the second planetary gear mechanism PGS2, the third brake B3 is disposed radially outward of the third clutch C3, and the first brake B1 is the third planetary gear mechanism. The second brake B2 is disposed radially outward of the first clutch C1 and is disposed radially outward of the PGS3. As described above, when the four brakes B1 to B4 are arranged radially outward of the planetary gear mechanism or the clutch, the brakes B1 to B4 are arranged side by side on the axis of the input shaft 2 together with the planetary gear mechanism and the clutch. Compared to the above, the axial length of the automatic transmission TM can be shortened. The fourth brake B4 may be disposed radially outward of the second clutch C2, and the third brake B3 may be disposed radially outward of the second planetary gear mechanism PGS2.

  Next, with reference to FIG. 3 and FIG. 4, the case where each gear stage of the automatic transmission TM of embodiment is established is demonstrated.

  When establishing the first gear, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state ("R" in FIG. 4), and the second brake B2 and the third brake B3 are set in the fixed state. By setting the first brake B1 to the reverse rotation prevention state, the reverse rotation of the third coupled body Cc-Cd is prevented. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 becomes “0”. The rotational speed of the third coupled body Cc-Cd is also “0”.

  As a result, the seventh to ninth elements Sc, Cc, Rc of the third planetary gear mechanism PGS3 enter a locked state in which the third planetary gear mechanism PGS3 cannot rotate relative to each other, and include the ring gear Rc (the ninth element) of the third planetary gear mechanism PGS3. The rotational speed of the first coupling body Ca-Cb-Rc is also "0". Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “1st” shown in FIG. 4, and the first gear is established.

  In order to establish the first gear, the third brake B3 does not need to be in a fixed state, but is fixed in the first gear so that a smooth shift can be made from the first gear to the second gear described later. Yes. Further, when the engine brake is applied at the first speed, the first brake B1 including the two-way clutch may be switched to the fixed state (“L” in FIG. 4).

  When establishing the second gear, the first brake B1 as a two-way clutch is set in the reverse rotation prevention state ("R" in FIG. 4), the second brake B2 and the third brake B3 are set in the fixed state, and the third clutch C3 is set. Is connected. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 becomes “0”. Further, by setting the third brake B3 to the fixed state, the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 becomes “0”.

  Further, when the third clutch C3 is in the connected state, the rotation speed of the second coupling body Ra-Sd is set to “0”, which is the same speed as the rotation speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2. Become. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “2nd” shown in FIG. 3, and the second gear is established.

  When establishing the third gear, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the second brake B2 and the third brake B3 are set in the fixed state, and the second clutch C2 is set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 becomes “0”. Further, by setting the third brake B3 to the fixed state, the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 becomes “0”.

  Further, by setting the second clutch C2 in the connected state, the rotational speed of the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 is adjusted to the sun gear Sa of the first planetary gear mechanism PGS1 connected to the input shaft 2. “1”, which is the same speed as the rotation speed of the (first element). Since the rotation speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 is "0" and the rotation speed of the ring gear Rb (fourth element) is "1", the rotation of the carrier Cb (fifth element) The speed, that is, the rotational speed of the first connected body Ca-Cb-Rc is i / (i + 1). Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “3rd” shown in FIG. 3, and the third gear is established.

  When establishing the fourth speed, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the second brake B2 is set in the fixed state, and the second clutch C2 and the third clutch C3 are set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 becomes “0”.

  Further, by setting the third clutch C3 to the connected state, the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 and the second connected body Ra-Sd rotate at the same speed. Thereby, between the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2, the carrier Ca (second element) and the carrier Cb (fifth element) are coupled, and the ring gear Ra (third element) is connected. The sun gear Sb (sixth element) is connected, and in the fourth speed stage in which the third clutch C3 is connected, the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2 One collinear diagram can be drawn.

  Then, by bringing the second clutch C2 into the connected state, the rotation speed of the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 is the rotation of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. The rotational speed of two rotational elements among the four rotational elements constituted by the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2 is “1”, which is the same speed as the speed. Become.

  Accordingly, the elements of the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2 are locked so as not to be relatively rotatable, and the rotational speeds of all the elements of the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2 are “1”. " The rotational speed of the third coupled body Cc-Cd is j / (j + 1), and the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is coupled is shown in FIG. “4th” and the fourth gear is established.

  When establishing the fifth gear, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the second brake B2 is set in the fixed state, and the first clutch C1 and the second clutch C2 are set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward. Further, by setting the second brake B2 in a fixed state, the rotational speed of the sun gear Sc (seventh element) of the third planetary gear mechanism PGS3 becomes “0”.

  Further, by setting the first clutch C1 in the connected state, the rotational speed of the third coupled body Cc-Cd is set to “1” which is the same speed as the rotational speed of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. Become. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “5th” shown in FIG. 3, and the fifth gear is established.

  Note that the second clutch C2 does not need to be in a connected state in order to establish the fifth gear. However, since the second clutch C2 needs to be in a connected state at the fourth speed and the sixth speed described later, downshift from the fifth speed to the fourth speed and from the fifth speed to the sixth speed described later. The 5th gear is in a connected state so that the upshift can be performed smoothly.

  When the sixth speed is established, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, and the first to third clutches C1 to C3 are set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward.

  In addition, the second clutch C2 and the third clutch C3 are in the connected state, so that the respective elements of the first planetary gear mechanism PGS1 and the second planetary gear mechanism PGS2 are not relatively rotatable as described in the fourth speed. Thus, the rotational speed of the second connected body Ra-Sd becomes “1”. Moreover, the rotational speed of 3rd coupling body Cc-Cd will be "1" by making the 1st clutch C1 into a connection state.

  Accordingly, in the fourth planetary gear mechanism PGS4, the carrier Cd (11th element) and the sun gear Sd (12th element) are set to “1” at the same speed, and each element is in a locked state in which relative rotation is impossible. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “1” of “6th” shown in FIG. 3, and the sixth gear is established.

  When establishing the seventh gear, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the third brake B3 is fixed, and the first clutch C1 and the second clutch C2 are connected. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward.

  Further, by setting the third brake B3 to the fixed state, the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the second clutch C2 in the connected state, the rotation speed of the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 is adjusted to the rotation of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. The speed is equal to “1”, and the rotational speed of the first connected body Ca-Cb-Rc including the carrier Cb (fifth element) of the second planetary gear mechanism PGS2 is i / (i + 1).

  Further, by setting the first clutch C1 in the connected state, the rotational speed of the third coupling body Cc-Cd is the rotational speed of the sun gear Sa (first element) of the first planetary gear mechanism PGS1 connected to the input shaft 2. And “1” at the same speed. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “7th” shown in FIG. 3, and the seventh gear is established.

  When establishing the eighth speed, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the third brake B3 is set in the fixed state, and the first clutch C1 and the third clutch C3 are set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward.

  Further, by setting the third brake B3 to the fixed state, the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the third clutch C3 in the connected state, the rotational speed of the second coupling body Ra-Sd is set to “0”, which is the same speed as the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2. Become. Further, by setting the first clutch C1 in the connected state, the rotational speed of the third coupled body Cc-Cd is set to “1” which is the same speed as the rotational speed of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. Become. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “8th” shown in FIG. 3, and the eighth gear is established.

  When establishing the ninth gear, the first brake B1, which is a two-way clutch, is set in the reverse rotation prevention state, the third brake B3 and the fourth brake B4 are set in the fixed state, and the first clutch C1 is set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward.

  Further, by setting the third brake B3 to the fixed state, the rotational speed of the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the fourth brake B4 in a fixed state, the rotational speed of the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 also becomes “0”. For this reason, each element Sb, Cb, Rb of the second planetary gear mechanism PGS2 is in a locked state in which the relative rotation is impossible, and the first coupled body Ca-Cb- including the carrier Cb (fifth element) of the second planetary gear mechanism PGS2. The rotational speed of Rc is also “0”.

  Further, by setting the first clutch C1 in the connected state, the rotational speed of the third coupled body Cc-Cd becomes “1” which is the same speed as the rotational speed of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. Become. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “9th” shown in FIG. 3, and the ninth gear is established.

  When establishing the tenth speed, the first brake B1 as a 2-way clutch is set in the reverse rotation prevention state, the fourth brake B4 is set in the fixed state, and the first clutch C1 and the third clutch C3 are set in the connected state. By setting the first brake B1 in the reverse rotation preventing state, the third linked body Cc-Cd is allowed to rotate forward.

  Further, by setting the third clutch C3 in the connected state, the second connected body Ra-Sd and the sun gear Sb (sixth element) of the second planetary gear mechanism PGS2 rotate at the same speed. Further, by setting the fourth brake B4 in a fixed state, the rotational speed of the ring gear Rb (fourth element) of the second planetary gear mechanism PGS2 becomes “0”. Further, by setting the first clutch C1 in the connected state, the rotational speed of the third coupled body Cc-Cd becomes “1” which is the same speed as the rotational speed of the sun gear Sa (first element) of the first planetary gear mechanism PGS1. Become. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “10th” shown in FIG. 3, and the tenth speed stage is established.

  When establishing the reverse gear, the first brake B1, which is a two-way clutch, is set in a fixed state, the third brake B3 is set in a fixed state, and the second clutch C2 is set in a connected state. Further, by setting the third brake B3 in the fixed state and the second clutch C2 in the connected state, the rotational speed of the first connected body Ca-Cb-Rc becomes i / (i + 1). Further, by setting the first brake B1 in the fixed state, the rotation of the third coupling body Cc-Cd is prevented, and the rotation speed of the third coupling body Cc-Cd becomes “0”. Then, the rotational speed of the ring gear Rd (tenth element) of the fourth planetary gear mechanism PGS4 to which the output unit 3 is connected becomes “Rvs” of the reverse rotation shown in FIG. 3, and the reverse gear is established.

  In addition, the speed line shown with the broken line in FIG. 3 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. 4 is a diagram summarizing and displaying the states of the clutches C1 to C3 and the brakes B1 to B4 at each of the above-described shift speeds. The first to third clutches C1 to C3 and the second brake B2 to the fourth are shown in FIG. “◯” in the row of the brake B4 indicates a connected state or a fixed state, and a blank indicates an open state. Further, “R” in the row of the first brake B1 indicates a reverse rotation prevention state, and “L” indicates a fixed state.

  Underlined “R” and “L” indicate that the rotation speed of the third coupling body Cc-Cd becomes “0” by the action of the first brake B1. “R / L” is “R” in the reverse rotation prevention state at normal times, but indicates switching to “L” in the fixed state when the engine brake is applied.

  4 shows that the gear ratio h of the first planetary gear mechanism PGS1 is 2.734, the gear ratio i of the second planetary gear mechanism PGS2 is 1.614, and the gear ratio j of the third planetary gear mechanism PGS3 is 2. 681, and the gear ratio k of the fourth planetary gear mechanism PGS4 when the gear ratio k is 1.914 (the rotational speed of the input shaft 2 / the rotational speed of the output unit 3) and the common ratio (between each gear) The ratio of the gear ratio of the predetermined gear stage divided by the gear ratio of the gear stage one speed higher than the predetermined gear stage is also shown. It can be seen that can be set.

  Next, the two-way clutch will be described in detail with reference to FIG. The first brake B1 is a two-way switchable between a fixed state in which the third coupling body Cc-Cd is fixed to the housing 1 and a reverse rotation prevention state in which the third coupling body Cc-Cd is allowed to rotate forward and prevents reverse rotation. It consists of a clutch. An example of this two-way clutch will be described in detail with reference to FIG.

  The two-way clutch TW as the first brake B1 in FIG. 5 is disposed with an inner ring TW1 coupled to the third coupling body Cc-Cd and a radially outer side of the inner ring TW1 with a space therebetween. 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 a meshing mechanism that is not shown.

  The meshing mechanism is configured to be switchable between an outer connection state in which the outer ring TW2 and the holding ring TW3 are connected and an inner connection state in which the inner ring TW1 and the holding ring TW3 are connected.

  Further, as shown in FIG. 5A, the diameter of the roller TW4 is such that the gap A is opened when the roller TW4 is in the center of the cam surface TW1a, and as shown in FIGS. 5B and 5C, 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 outer ring TW2 and the holding ring TW3 are connected to each other by the meshing mechanism, the inner ring TW1 is rotated in either the forward rotation or the reverse rotation as shown in FIGS. 5B and 5C. As shown, since the holding ring TW3 is also fixed to the casing 1, the roller TW4 is positioned at the end of the cam surface TW1a.

  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.

  In the inner coupling state where the inner ring TW1 and the holding ring TW3 are coupled, the meshing mechanism (not shown) is in a state where the notch hole TW3a is located at one end of the cam surface TW1a as shown in FIG. It is configured as follows.

  Assuming that the clockwise direction in FIG. 5 is the reverse rotation direction, the two-way clutch TW enters the reverse rotation prevention state by setting the inner connection state in which the inner ring TW1 and the holding ring TW3 are connected.

  In addition, a shift lever 42 (shift position detection unit) of a shift-by-wire type in which the shift position can be switched to any one of the forward range, the neutral range, and the reverse range is mounted on a vehicle on which the automatic transmission TM of the present embodiment is mounted. And an oil temperature detection unit 43a for detecting the temperature (oil temperature) of the oil in the hydraulic control circuit 43, a vehicle speed detection unit 44 for detecting the traveling speed of the vehicle, and an engine brake for detecting whether or not the engine is in a brake state. A determination unit 46, a drive source rotational speed detection unit 48 that detects the rotational speed of the drive source ENG, an input rotational speed detection unit 50 that detects the rotational speed of the input shaft 2, and a brake that detects whether the brake pedal is on or off. A pedal detector 54 and an accelerator opening detector 56 for detecting whether the accelerator pedal is on or off are provided.

  In FIG. 1, the engine brake determination unit 46 is illustrated as being different from the control unit ECU, but actually, the control unit ECU functions as the engine brake determination unit 46.

  The control unit ECU includes information on the shift position of the shift lever 42, information on the oil temperature (oil temperature) of the hydraulic control circuit 43 from the oil temperature detection unit 43a, information on the traveling speed of the vehicle from the vehicle speed detection unit 44, engine Information on whether or not the engine is in an engine brake state from the brake determination unit 46, information on the rotational speed of the drive source ENG from the drive source rotational speed detection unit 48, and the rotational speed of the input shaft 2 from the input rotational speed detection unit 50 The information, the brake pedal on / off information from the brake pedal detector 54, and the accelerator pedal on / off information from the accelerator opening detector 56 are received.

  Next, referring to FIG. 6 and FIG. 7, in the automatic transmission TM of this embodiment, the vehicle is traveling backward and the shift position is switched from the reverse range to the forward range by the driver's shift operation. The operation of the control unit ECU will be described. The control unit ECU executes the process of the flowchart shown in FIG. 6 with a predetermined cycle time.

  In the flow of FIG. 6 and FIG. 7, it is assumed that the first brake B1 is in a fixed state (B1 → L). FIG. 8 shows a state transition when the first brake B1 is in the reverse rotation prevention state (R) (B1 → R). “Map” in FIGS. 7 and 8 indicates that normal control is performed based on map data stored in the control unit. Further, in the present embodiment, the description will be made assuming that the vehicle traveling speed can be measured only by an absolute value and the vehicle speed cannot be separated forward and backward.

  In the flow of FIG. 6, first, when the vehicle is traveling backward in step 1, it is determined whether or not the shift position has been switched from the reverse range to the forward range by the driver's shift operation. If the reverse range remains, the current process is terminated. When it is switched to the forward range in step 1, the process proceeds to step 2 to determine whether or not the idle neutral engagement state is established.

  In this embodiment, the idle neutral engagement state means that the control unit ECU sets the third brake B3 in a fixed state so that the input shaft 2 can freely rotate and the output unit 3 is prevented from rotating. The third clutch C3 is defined as being in a connected state.

  If it is determined in step 2 that the idle neutral engagement state is not established, the process proceeds to step 3 to determine whether or not neutral control (N (D prohibited)) is being performed. When the neutral control (N (D prohibited)) is not being performed, the routine proceeds to step 4 where it is determined whether or not the first-speed in-gear is being performed. If it is not in the first speed in-gear, the process proceeds to step 5 to determine whether or not the vehicle speed V (the vehicle speed in the reverse direction in this case) as the travel speed of the vehicle is less than the first predetermined speed.

  If the vehicle speed V is not less than the first predetermined speed in step 4, in other words, if the vehicle speed V is greater than or equal to the first predetermined speed, the process proceeds to step 6 where the vehicle speed V is greater than the first predetermined speed. It is determined whether or not the vehicle speed is equal to or less than a second predetermined speed that is a vehicle speed as a condition for shifting to the idle neutral engagement state.

  If it is determined in step 6 that the vehicle speed V is equal to or lower than the second predetermined speed, the process proceeds to step 7 where the third brake B3 remains connected (engaged) and the second clutch C2 is released ( off) and the third clutch C3 is set to the engaged state (on) to shift to the idle neutral engaged state (I / N mode), and the current process is terminated.

  In step 6, if the vehicle speed V is not less than or equal to the second predetermined speed, in other words, if the vehicle speed V exceeds the second predetermined speed, the process branches to step 8 and the engagement mechanism is controlled so as to be in the neutral state. Neutral control (N (D prohibited)) is executed (for example, only the third brake B3 is left in a fixed state and the second clutch C2 is in a released state), and the current process is terminated.

  If it is determined in step 3 that neutral control (N (D prohibited)) is being performed, the process branches to step 9 to determine whether or not the vehicle speed V is less than the first predetermined speed. If the vehicle speed V is not less than the first predetermined speed, in other words, if the vehicle speed V is greater than or equal to the first predetermined speed, the process branches to step 8 and the neutral control (N (D prohibited)) is executed and this time as it is. Terminate the process.

  If the vehicle speed V is less than the first predetermined speed in step 9, the process proceeds to step 10 where the second clutch C2 is disengaged (off) while the third brake B3 is fixed, and the second brake is applied. The first speed in-gear mode with B2 in the fixed state (on) is executed, and the current process is terminated.

  If it is determined in step 4 that the first speed in-gear mode is being executed, the process branches to step 10 to directly execute the first speed in-gear mode and the current process is terminated. If the vehicle speed V is less than the first predetermined speed in step 5, the process branches to step 10 to execute the first speed in-gear mode and the current process is terminated.

  If it is determined in step 2 that the engine is in the idle neutral engagement state, the process branches to step 11 to determine whether or not the vehicle speed V is equal to or lower than a third predetermined speed at which there is no possibility of engine stall. Here, the third predetermined speed is set to a speed that is slower than the first predetermined speed, has a low input load to the torque converter, and does not cause the engine stall.

  If the vehicle speed V is not less than the third predetermined speed, in other words, if the vehicle speed V is greater than or equal to the third predetermined speed, the process proceeds to step 7 where the idle neutral control is continued and the current process is terminated.

  If the vehicle speed V is less than or equal to the third predetermined speed in step 11, the process branches to step 12, the third clutch C3 is set in the released state (off), the second brake B2 is set in the fixed state (on), and the idle neutral engagement is performed. The combined state is terminated and the current process is terminated.

  When the driving wheel is locked and slips in the idle neutral engagement state, the control unit ECU appropriately controls the engagement mechanisms C1 to C3 and B2 to B4 so that the lock can be released. .

  Further, in the present embodiment, as shown in FIG. 7B, the first brake B1 is switched from the fixed state (L) to the reverse rotation preventive state (R) in the idle neutral engagement state (I / N). The switching of the first brake B1 during the idle neutral engagement (I / N) will be described in detail with reference to the flowchart of FIG.

  First, in step 21, the control unit ECU confirms whether or not the idle neutral engagement state is established. If it is not in the idle neutral engagement state, the current process is terminated. If it is in the idle neutral engagement state, the process proceeds to step 22 to check whether or not the first brake B1 is in the middle of switching from the fixed state (L) to the reverse rotation prevention state (R).

  If it is not in the middle of switching the first brake in step 22, the process proceeds to step 23 to check whether or not the first brake B1 is in the fixed state (L). When the first brake B1 is not in the fixed state (L) but in the reverse rotation prevention state (R), the current process is terminated.

  In step 23, when the first brake B1 is in the fixed state (L), the process proceeds to step 24, and the hydraulic pressure supplied to the third clutch C3 is set to such an extent that the third clutch C3 can be regarded as completely engaged. Check if it is over the set value. If the hydraulic pressure supplied to the third clutch C3 is less than the set value, the current process is terminated.

  In step 24, if the hydraulic pressure supplied to the third clutch C3 is equal to or greater than the set value, the process proceeds to step 25, and it is confirmed whether or not the deceleration of the vehicle is equal to or less than a predetermined value. Here, in the present embodiment, the predetermined value is set to a value to which a load that can smoothly switch the first brake B1 is applied by deceleration of the vehicle. The deceleration of the vehicle may be determined using, for example, an estimation of the brake braking force from the brake fluid pressure, an estimated value of the vehicle traveling path gradient, and the like.

  In step 25, if the deceleration of the vehicle is equal to or less than the predetermined value, the process proceeds to step 26, where the process of switching the first brake B1 from the fixed state (L) to the reverse rotation prevention state (R) is executed. The process ends.

  Here, when a relatively large load is applied to the first brake B1, the first brake B1 as the switching mechanism cannot be smoothly switched from the fixed state (L) to the reverse rotation preventive state (R). In the present embodiment, when the deceleration of the vehicle is equal to or less than a predetermined value, the first brake B1 is switched from the fixed state (L) to the reverse rotation prevention state (R), so that a large load accompanying the vehicle deceleration is applied. When not, the first brake B1 can be switched. Therefore, the first brake B1 can be switched smoothly.

  If it is determined in step 22 that the first brake is being switched, the process proceeds to step 26 where the process of switching the first brake B1 from the fixed state (L) to the reverse rotation prevention state (R) is executed, and this process ends. .

  When shifting from the reverse in-gear (RVS) to the first-speed in-gear (LOW) without entering the idle neutral engagement state, for example, in the case of FIGS. 7A and 7C, the first-speed in-gear is used. After shifting to, the first brake B1 is switched from the fixed state to the reverse rotation preventing state. However, even when the idle neutral engagement state is not established, the first brake B1 is switched from the fixed state to the reverse rotation preventive state and the second brake B2 is set in the fixed state before the shift to the first speed in gear, and the second speed in gear is performed. Then, the third clutch C3 may be switched to the disengaged state to set the first speed in-gear.

  According to the automatic transmission TM of the present embodiment, when the vehicle is traveling in reverse and the vehicle speed is equal to or lower than the second predetermined speed and equal to or higher than the first predetermined speed, the input shaft 2 can freely rotate and the output unit 3 The engagement mechanism is controlled so that the second clutch C2 is released, the third clutch C3 is engaged, and the idle neutral engagement state is established. In addition, when the vehicle speed exceeds the second predetermined speed, if the rotation of the output unit 3 is prevented, the driving wheels may be locked and slip.

  Therefore, when the vehicle speed exceeds the second predetermined speed, the vehicle waits for the vehicle speed to fall below the first predetermined speed as neutral, and after decelerating to below the first predetermined speed, the first speed in-gear is set.

  Thereby, even if the vehicle is traveling in the reverse direction, the reverse rotation of the turbine of the torque converter can be prevented. Therefore, according to the automatic transmission TM of the present embodiment, input of a high load to the torque converter when the reverse range is switched to the forward range can be prevented, and engine stall can be prevented. When the vehicle is traveling in reverse and the vehicle speed is less than the first predetermined speed, there is no risk of high load input to the torque converter. For this reason, it can transfer to 1st-speed in-gear immediately.

  In the idle neutral engagement state, when the vehicle deceleration is equal to or lower than a predetermined value, the first brake B1 as the switching mechanism is switched from the fixed state (L) to the reverse rotation prevention state (R). Thereby, it is possible to prevent the first brake B1 as the switching mechanism from being switched from the fixed state (L) to the reverse rotation preventing state (R) in a state where a relatively large load is applied, and the first brake B1 can be smoothly moved. And can smoothly transition from the idle neutral engagement state to the first-speed in-gear state.

  Note that the automatic transmission TM according to the present embodiment may be configured such that any one of the shift speeds (for example, the 10th speed) is omitted and the forward 9th speed is changed.

  In the present embodiment, the shift position is changed by operating a shift-by-wire type shift lever. However, the shift position switching method is not limited to this. For example, the shift position may be switched by pressing a button or the like. In this case, for example, the shift position selected from the button pressing signal can be determined.

  Further, in the present embodiment, the load related to the switching mechanism is determined based on the deceleration of the vehicle. However, the present invention is not limited to this, and the load related to the switching mechanism is estimated to determine the switching mechanism. If it is configured to switch from the fixed state (L) to the reverse rotation prevention state (R) when the vehicle can be switched smoothly, the determination may be made based on other vehicle information.

  For example, when the engine brake is applied during traveling in the reverse gear, a load that impedes this switching is applied when attempting to switch from the fixed state (L) to the reverse rotation preventing state (R). No state. For this reason, when the shift position is switched while the engine brake is operating in the reverse speed, the switching mechanism may be switched before shifting to the idle neutral engagement state. . Whether or not the engine brake is operating can be determined based on, for example, a change in the rotational speed of the drive source ENG with respect to the traveling speed of the vehicle, a slip amount (torque slip ratio) of the torque converter, or the like.

  A specific example in this case will be described in detail with reference to a flowchart of another embodiment shown in FIG. As shown in the flowchart of FIG. 10, first, in step 31, it is confirmed whether or not the shift position is switched from the reverse range to the forward range by the driver's shift operation. If it has not been switched, the current process is terminated.

  If it is switched to the forward range in step 31, the routine proceeds to step 32 where it is confirmed whether or not the idle neutral engagement state is established. If it is not in the idle neutral engagement state, the process proceeds to step 33 to check whether or not the first brake B1 is in the reverse rotation prevention state (R). If the first brake B1 is not in the reverse rotation prevention state (R), the routine proceeds to step 34, where it is confirmed whether or not the first brake B1 is in the process of being switched from the fixed state (L) to the reverse rotation prevention state (R). .

  If the first brake B1 is not in the middle of switching from the fixed state (L) to the reverse rotation prevention state (R), the process proceeds to step 35 to check whether or not the slip ratio of the torque converter is equal to or greater than a specified value. Here, the specified value is set to a value when the engine brake starts to work. In other words, when the slip rate of the torque converter is equal to or greater than the specified value, the engine brake is in use.

  If the slip ratio is greater than or equal to the specified value in step 35, the engine brake is working, so the process proceeds to step 36, where the first brake B1 is switched from the fixed state (L) to the reverse rotation prevention state (R). Terminate the process.

  If it is determined in step 32 that the engine is in the idle neutral engaged state, the process branches to step 37, where the control in the idle neutral engaged state is executed, and the current process is terminated.

  If it is determined in step 33 that the first brake B1 is in the reverse rotation prevention state (R), the process branches to step 37, the control in the idle neutral engagement state is executed, and the current process is terminated.

  If it is determined in step 34 that the first brake B1 is being switched from the fixed state (L) to the reverse rotation prevention state (R), the process proceeds to step 36, and then the first brake B1 is reversely rotated from the fixed state (L). The control for switching to the blocking state (R) is executed, and the current process is terminated.

  If it is determined in step 35 that the slip ratio is less than the specified value, the process branches to step 37 to execute the control in the idle neutral engagement state, and the current process is terminated. In this case, the first brake B1 is switched from the fixed state (L) to the reverse rotation prevention state (R) when in the idle neutral engagement state.

  Note that all the flowcharts used in the description of the embodiment are repeatedly executed at a predetermined cycle.

DESCRIPTION OF SYMBOLS 1 ... Housing | casing 2 ... Input shaft (input part), 3 ... Output part (output gear), 42 ... Shift lever (shift position detection part), 43 ... Hydraulic circuit, 43a ... Temperature detection part, 43b ... Solenoid valve, 43c ... hydraulic switch, TM ... automatic transmission, 44 ... vehicle speed detection unit, 46 ... engine brake determination unit, 48 ... drive source rotational speed detection unit, 50 ... input rotational speed detection unit, 54 ... brake pedal detection unit, 56 ... Accelerator opening detector, 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 (sixth element), Cb ... carrier (fifth element), Rb ... ring Ya (fourth element), Pb ... pinion, PGS3 ... third planetary gear mechanism, Sc ... sun gear (seventh element), Cc ... carrier (eighth element), Rc ... ring gear (ninth element), Pc ... pinion, PGS4 ... 4th planetary gear mechanism, Sd ... sun gear (12th element), Cd ... carrier (11th element), Rd ... ring gear (10th element), Pd ... pinion, C1 ... 1st clutch, C2 ... 2nd clutch (Second friction engagement mechanism), C3 ... third clutch, B1 ... first brake (switching mechanism), B2 ... second brake (first friction engagement mechanism), B3 ... third brake, B4 ... fourth brake , ECU: Control unit.

Claims (2)

An input unit that is disposed within the housing and through which the power of the drive source is transmitted via a torque converter;
A planetary gear mechanism having a plurality of elements rotatable within the housing;
A plurality of engagement mechanisms switchable to a connected state in which the elements are connected to each other, or switchable to a fixed state in which the elements are fixed to the housing;
An output section;
A shift position detector for detecting the shift position;
An input rotation speed detection unit for detecting the rotation speed of the input unit;
A control unit that receives information on the rotational speed detected from the input rotational speed detection unit and information on the shift position from the shift position detection unit, and controls the engagement mechanism;
An automatic transmission capable of shifting the rotation of the input unit to a plurality of stages and outputting from the output unit,
And forward rotation of the rotation direction the same direction of the input portion, wherein when the rotation of the forward and reverse direction is reversed, allowing the forward rotation of one element of the plurality of said elements, said Comprising a switching mechanism capable of switching between a reverse rotation preventing state for preventing reverse rotation and a fixed state for fixing the element to the housing;
The controller is
When the shift position is in the forward range, the switching mechanism is in the reverse rotation prevention state, and when the shift position is in the reverse range, the switching mechanism is in the fixed state,
When the vehicle is traveling backward and the shift position is switched from the reverse range to the forward range and the vehicle speed is equal to or higher than the first predetermined speed, the input unit can freely rotate and the output unit cannot be rotated. The idle neutral engagement state for controlling the engagement mechanism to be
An automatic transmission characterized in that, in the idle neutral engagement state, the switching mechanism is switched from the fixed state to the reverse rotation prevention state when the deceleration of the vehicle is equal to or less than a predetermined value. An input unit that is disposed within the housing and through which the power of the drive source is transmitted via a torque converter;
A planetary gear mechanism having a plurality of elements rotatable within the housing;
A plurality of engagement mechanisms switchable to a connected state in which the elements are connected to each other, or switchable to a fixed state in which the elements are fixed to the housing;
An output section;
A shift position detector for detecting the shift position;
An input rotation speed detection unit for detecting the rotation speed of the input unit;
A control unit that receives information on the rotational speed detected from the input rotational speed detection unit and information on the shift position from the shift position detection unit, and controls the engagement mechanism;
An automatic transmission capable of shifting the rotation of the input unit to a plurality of stages and outputting from the output unit,
And forward rotation of the rotation direction the same direction of the input portion, wherein when the rotation of the forward and reverse direction is reversed, allowing the forward rotation of one element of the plurality of said elements, said Comprising a switching mechanism capable of switching between a reverse rotation preventing state for preventing reverse rotation and a fixed state for fixing the element to the housing;
The controller is
When the shift position is in the forward range, the switching mechanism is in the reverse rotation prevention state, and when the shift position is in the reverse range, the switching mechanism is in the fixed state,
When the vehicle is traveling backward and the shift position is switched from the reverse range to the forward range and the vehicle speed is equal to or higher than the first predetermined speed, the input unit can freely rotate and the output unit cannot be rotated. The idle neutral engagement state for controlling the engagement mechanism to be
When the vehicle is traveling in the reverse direction and the shift position is switched from the reverse range to the forward range and the engine brake is applied, the switching mechanism is changed from the fixed state to the reverse rotation preventive state. Automatic transmission characterized by switching.