JP5161193B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission that shifts the rotation of an input shaft to a plurality of stages through a plurality of planetary gear mechanisms disposed in a transmission case and transmits the rotation to an output member.

  2. Description of the Related Art Conventionally, there has been known an automatic transmission that can perform eight forward speeds using a first planetary gear for input, two planetary gears for shifting, and six engagement mechanisms (for example, Patent Document 1).

  In Patent Document 1, a pair of first pinions in which a first planetary gear for input meshes with a first sun gear and a first ring gear, one meshes with the first sun gear and the other meshes with the first ring gear. Is constituted by a double pinion type planetary gear mechanism comprising a first carrier that pivotally supports and rotates freely.

  The first planetary gear decelerates the rotation speed of the first carrier, which is a fixed element that fixes the first sun gear to the transmission case, the input element that connects the first carrier to the input shaft, and the first carrier that serves as the input element. Output element to be

  Further, 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 is engaged with the second sun gear and the second ring gear. The other is composed of 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 has a first rotation element and a second rotation in order with an interval corresponding to the gear ratio in a speed diagram (a ratio of relative speeds of the respective rotation elements can be represented by a straight line). When the 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 integrated with the third ring gear. The converted second ring gear and fourth rotation element become the third sun gear.

  Further, the engaging mechanism includes a first wet multi-plate clutch that releasably connects a first ring gear that is an output element of the first planetary gear and a fourth rotating element that is a third sun gear, an input shaft, and a second carrier. A second wet multi-plate clutch that releasably connects the second rotating element, and a third wet multi-plate clutch that releasably connects the first rotating element comprising the first ring gear and the 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 are releasably fixed to the transmission case. A first brake and a second brake for releasably fixing a second rotating element including the second carrier to the transmission case are provided.

  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.

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.

  The piston of the wet multi-plate clutch is provided on the input shaft or the main shaft that supports the input shaft, unlike the wet multi-plate brake piston provided in the transmission case, and the radial direction of the planetary gear. Cannot be placed outside.

  Therefore, in the conventional example, a total of seven members including three planetary gear mechanisms and four wet multi-plate clutches are arranged on the input shaft or the main shaft that rotatably supports the input shaft, so that automatic transmission There is an inconvenience that the shaft length of the machine becomes long and the mountability to a vehicle (particularly FF type vehicle) is low.

  In view of the above, an object of the present invention is to provide an automatic transmission that can reduce friction loss and can be mounted on a vehicle.

  [1] To achieve the above object, according to the present invention, an output member is provided by shifting the rotation of an input shaft that is rotatably supported in a transmission case and rotated by power from a drive source into a plurality of stages. The first to fourth planetary gear mechanisms each having three elements including a sun gear, a carrier, and a ring gear are provided, and the three elements of the first planetary gear mechanism are connected to a speed line. The first element, the second element, and the third element are arranged in the order corresponding to the gear ratio in the drawing, respectively, and the three elements of the second planetary gear mechanism are arranged in the speed chart corresponding to the gear ratio. The fourth element, the fifth element, and the sixth element are sequentially arranged, and the three elements of the third planetary gear mechanism are respectively arranged in the order corresponding to the gear ratio in the velocity diagram in the order of the seventh element and the eighth element. And the ninth element, and the three elements of the fourth planetary gear mechanism are respectively arranged in the order corresponding to the gear ratio in the velocity diagram in the order of the tenth element, the eleventh element, and the twelfth element. Connected to the input shaft, the eleventh element is connected to the output member, the second element, the seventh element, and the tenth element are connected to form a first connecting body, and the third element And the fifth element are connected to form a second connected body, the sixth element, the eighth element, and the twelfth element are connected to form a third connected body, and the first connected body Any one of the first wet multi-plate clutch that can be switched between a connected state that connects the first element and the fourth element, and an open state that breaks the connection, and the first to third elements of the first planetary gear mechanism. Connected to each other and open to break this connection A second wet multi-plate clutch switchable to a state, a fixed state in which the second coupling body is fixed to the transmission case, and a first brake switchable to an open state in which the fixing is released; A second brake that can be switched between a fixed state in which the four elements are fixed to the transmission case and an open state in which the fixing is released; a fixed state in which the ninth element is fixed to the transmission case; and And a third brake switchable to an open state to be released.

  According to the present invention, as will be apparent from the description of the embodiment to be described later, it is possible to perform a forward eight-speed shift, and each of five engagement mechanisms of a total of two wet multi-plate clutches and three brakes. The two engagement mechanisms are engaged at the shift speed. For this reason, the number of engagement mechanisms opened at each shift stage is three, and the friction loss due to the opened engagement mechanisms is reduced as compared with the conventional one where four engagement mechanisms are opened. The transmission efficiency of the automatic transmission can be improved.

  Further, four planetary gear mechanisms and two wet multi-plate clutches are arranged on the axis of the input shaft, and a total of six members are arranged. For this reason, the shaft length of the automatic transmission can be shortened as compared with the conventional product in which a total of seven members of three planetary gear mechanisms and four wet multi-plate clutches are arranged on the axis of the input shaft. And can be mounted on a vehicle (particularly an FF vehicle).

  [2] In the present invention, a 1-way clutch that rotates integrally with the second coupling body is provided only when the second coupling body reverses, and a fixed state in which the 1-way clutch is fixed to the transmission case, It is preferable to provide the 4th brake which can be switched to the open state which cancels | releases.

  According to this, as will be apparent from the description of the embodiment described later, the first brake can be constituted by a wet multi-plate brake having a relatively small capacity, and the friction loss can be further reduced. In addition, the controllability of the shift between the shift speeds can be improved. Moreover, the 1-way clutch can be disabled by opening the fourth brake. Thereby, the reverse gear can be established.

  [3] In the present invention, the first brake is in a reverse rotation preventing state in which the second connected body is allowed to rotate in the forward direction to prevent reverse rotation, and the forward rotation of the second connected body is prevented in the forward direction and the reverse rotation is allowed. A two-way clutch that can be switched between states can also be used.

  According to this, the controllability of the shift is improved as will be apparent from the description of the embodiment described later. Further, at the shift stage where the second connecting body is in an open state where it is not fixed to the transmission case by the two-way clutch that is the first brake, no friction loss occurs in the two-way clutch that is the first brake. For this reason, the friction loss can be further reduced as the entire automatic transmission.

  [4] In the present invention, each of the four planetary gear mechanisms is constituted by a single-pinion type planetary gear mechanism including 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. It is preferable.

  According to this, the planetary gear mechanism is a double pinion type comprising a sun gear, a ring gear, and a carrier that rotatably and revolves a pair of pinions that mesh with each other and one meshes with the sun gear and the other meshes with the ring gear. Compared to the case of the planetary gear mechanism, the number of gear meshes in the power transmission path from the input shaft to the output member can be reduced, and the transmission efficiency can be improved.

The skeleton figure which shows the upper half of the automatic transmission of 1st Embodiment of this invention. The speed diagram 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 connection state of each engagement element in every gear stage of the automatic transmission of 1st Embodiment. The skeleton figure which shows the upper half of the automatic transmission of 2nd Embodiment of this invention. The speed diagram which shows the ratio of the relative speed of each element of the 1st-4th planetary gear mechanism of the automatic transmission of 2nd Embodiment. Explanatory drawing which shows the connection state of each engagement element in every gear stage of the automatic transmission of 2nd Embodiment.

[First Embodiment]
FIG. 1 shows an upper half of a first embodiment of an automatic transmission according to the present invention. The automatic transmission according to the first embodiment is disposed concentrically with an input shaft 2 that is rotatably supported in a transmission case 1 and connected to a power source such as an engine (not shown). And an output member 3 composed of an output gear. The rotation of the output member 3 is transmitted to the left and right drive wheels of the vehicle via a differential gear (not shown).

  In the transmission case 1, a first planetary gear mechanism 4, a second planetary gear mechanism 5, a third planetary gear mechanism 6, and a fourth planetary gear mechanism 7 are disposed concentrically with the input shaft 2. The first planetary gear mechanism 4 is composed of a single pinion type planetary gear mechanism that includes a sun gear Sa, a ring gear Ra, and a carrier Ca that rotatably and revolves a pinion Pa that meshes with the sun gear Sa and the ring gear Ra. Yes.

  Referring to the speed diagram of the first planetary gear mechanism 4 shown in the middle stage of FIG. 2 (the figure 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), the first planetary gear mechanism 4 Are the first element, the second element, and the third element from the left side in the order of arrangement at intervals corresponding to the gear ratio in the velocity diagram, 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 h: where the gear ratio of the first planetary gear mechanism 4 (number of teeth of the ring gear / number of teeth of the sun gear) is h: Set to 1. In the velocity diagram, 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.

  Similar to the first planetary gear mechanism 4, the second planetary gear mechanism 5 is a single gear comprising 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. It is composed of a pinion type planetary gear mechanism.

  Referring to the speed diagram of the second planetary gear mechanism 5 shown in the upper part of FIG. 2, the three elements Sb, Cb, Rb of the second planetary gear mechanism 5 are arranged in an order corresponding to the gear ratio in the speed diagram. Assuming that the fourth element, the fifth element, and the sixth element are from the left side, 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 5.

  Similar to the first and second planetary gear mechanisms 4 and 5, the third planetary gear mechanism 6 is a carrier Cc that supports the sun gear Sc, the ring gear Rc, and the pinion Pc that meshes with the sun gear Sc and the ring gear Rc so as to freely rotate and revolve. It consists of a single pinion type planetary gear mechanism.

  Referring to the speed diagram of the third planetary gear mechanism 6 shown in the lower part of FIG. 2, the three elements Sc, Cc, Rc of the third planetary gear mechanism 6 are arranged in an order corresponding to the gear ratio in the speed diagram. Assuming the seventh element, the eighth element, and the ninth element from the left side, the seventh element is the ring gear Rc, the eighth element is the carrier Cc, and the ninth element is the sun gear Sc. 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 6.

  Similar to the first to third planetary gear mechanisms 4 to 6, the fourth planetary gear mechanism 7 is a carrier Cd that supports the sun gear Sd, the ring gear Rd, and the pinion Pd that meshes with the sun gear Sd and the ring gear Rd so as to rotate and revolve. It consists of a single pinion type planetary gear mechanism.

  Referring to the velocity diagram of the fourth planetary gear mechanism 7 shown in the lower part of FIG. 2, the three elements Sd, Cd, Rd of the fourth planetary gear mechanism 7 are arranged in the order in which they correspond to the gear ratio in the velocity diagram. Assuming the tenth, eleventh and twelfth elements from the left, 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 7.

  The sun gear Sa (first element) of the first planetary gear mechanism 4 is connected to the input shaft 2. The carrier Cd (11th element) of the fourth planetary gear mechanism 7 is connected to the output member 3. In addition, the carrier Ca (second element) of the first planetary gear mechanism 4, the ring gear Rc (seventh element) of the third planetary gear mechanism 6, and the ring gear Rd (tenth element) of the fourth planetary gear mechanism 7 are connected to each other. 1 link body Ca-Rc-Rd is comprised.

  Also, the ring gear Ra (third element) of the first planetary gear mechanism 4 and the carrier Cb (fifth element) of the second planetary gear mechanism 5 are connected to form a second connected body Ra-Cb. Further, the ring gear Rb (sixth element) of the second planetary gear mechanism 5, the carrier Cc (eighth element) of the third planetary gear mechanism 6, and the sun gear Sd (twelfth element) of the fourth planetary gear mechanism 7 are connected. , Constituting the third linked body Rb-Cc-Sd.

  In the automatic transmission of the first embodiment, the four planetary gear mechanisms 4 to 7 cause the sun gear Sa (first element) of the first planetary gear mechanism 4, the first coupling body Ca-Rc-Rd, and the second coupling body Ra-Cb. The sun gear Sb (fourth element) of the second planetary gear mechanism 5, the third coupling body Rb-Cc-Sd, the sun gear Sc (ninth element) of the third planetary gear mechanism 6, and the carrier Cd (11th of the fourth planetary gear mechanism 7). 7 elements in total.

  The automatic transmission according to the first embodiment includes, as engagement mechanisms, first and second two wet multi-plate clutches C1 and C2, and first to third wet multi-plate brakes B1 to B3. Is provided. The first wet multi-plate clutch C1 can be switched between a connected state in which the first connecting member Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 are connected, and an open state in which this connection is cut off. It is configured.

  The second wet multi-plate clutch C2 is switched between a connected state in which the sun gear Sa (first element) of the first planetary gear mechanism 4 and the first connected body Ca-Rc-Rd are connected, and an open state in which this connection is broken. It is configured freely. The first wet multi-plate brake B1 is configured to be switchable between a fixed state in which the second coupling body Ra-Cb is fixed to the transmission case 1 and an open state in which this fixing is released.

  The second wet multi-plate brake B2 is configured to be switchable between a fixed state in which the sun gear Sb (fourth element) of the second planetary gear mechanism 5 is fixed to the transmission case 1 and an open state in which this fixing is released. . The third wet multi-plate brake B3 is configured to be switchable between a fixed state in which the sun gear Sc (9th element) of the third planetary gear mechanism 6 is fixed to the transmission case 1 and an open state in which this fixing is released. .

  In the automatic transmission according to the first embodiment, when the first gear is established, the first wet multi-plate clutch C1 is brought into a connected state and the first wet multi-plate brake B1 is brought into a fixed state. As a result, the first connected body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 rotate at the same speed, and the rotational speed of the second connected body Ra-Cb becomes "0". Become. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “1st” shown in FIG. 2, and the first gear is established.

  When the second gear is established, the first wet multi-plate brake B1 and the second wet multi-plate brake B2 are fixed. As a result, the rotational speeds of the second connected body Ra-Cb and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 become “0”, and the fourth to sixth elements Sb, Cb of the second planetary gear mechanism 5 are obtained. , Rb is in a locked state where relative rotation is impossible.

  Therefore, the rotational speed of the third coupling body Rb-Cc-Sd is also “0”, and the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 coupled to the output member 3 is “ 2nd ", the second gear is established.

  When the third speed is established, the first wet multi-plate brake B1 and the third wet multi-plate brake B3 are set in a fixed state. As a result, the rotational speeds of the second coupling body Ra-Cb and the sun gear Sc (the ninth element) of the third planetary gear mechanism 6 become “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “3rd” shown in FIG.

  When the fourth speed is established, the second wet multi-plate brake B2 and the third wet multi-plate brake B3 are set in a fixed state. As a result, the rotational speeds of the sun gear Sb (fourth element) of the second planetary gear mechanism 5 and the sun gear Sc (9th element) of the third planetary gear mechanism 6 become “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “4th” shown in FIG.

  When the fifth gear is established, the first wet multi-plate clutch C1 is brought into a connected state and the third wet multi-plate brake B3 is brought into a fixed state. As a result, the first connected body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 rotate at the same speed, and the sun gear Sc (9th element) of the third planetary gear mechanism 6 rotates. The speed becomes “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “5th” shown in FIG.

  When the sixth speed is established, the second wet multi-plate clutch C2 is brought into a connected state, and the third wet multi-plate brake B3 is brought into a fixed state. Thereby, since the sun gear Sa (first element) and the carrier Ca (second element) of the first planetary gear mechanism 4 rotate at the same speed, the first to third elements Sa and Ca of the first planetary gear mechanism 4 are rotated. , Ra are in a locked state where relative rotation is impossible, and the rotation speeds of the first to third elements Sa, Ca, Ra become “1”.

  Further, the rotational speed of the sun gear Sc (the ninth element) of the third planetary gear mechanism 6 becomes “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “6th” shown in FIG.

  When the seventh speed is established, the first wet multi-plate clutch C1 and the second wet multi-plate clutch C2 are brought into a connected state. As a result, the first to third elements Sa, Ca, Ra of the first planetary gear mechanism 4 are brought into a locked state in which relative rotation is impossible, and the rotation speed of the first to third elements Sa, Ca, Ra is “1”. "become. Further, the rotational speeds of the first coupling body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 are "1" which is the same speed.

  For this reason, all the elements of the planetary gear mechanisms 4 to 7 are locked so as not to be relatively rotatable, and the rotation speed of the carrier Cd (the eleventh element) of the fourth planetary gear mechanism 7 connected to the output member 3 is “1”. A certain “7th” is reached and the seventh gear is established.

  When the eighth speed is established, the second wet multi-plate clutch C2 is brought into a connected state, and the second wet multi-plate brake B2 is brought into a fixed state. As a result, the first to third elements Sa, Ca, Ra of the first planetary gear mechanism 4 are brought into a locked state in which relative rotation is impossible, and the rotation speed of the first to third elements Sa, Ca, Ra is “1”. "become. Further, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism 5 becomes “0”. Then, the rotation speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “8th” shown in FIG.

  When the reverse gear is established, the first wet multi-plate clutch C1 is brought into a connected state and the second wet multi-plate brake B2 is brought into a fixed state. As a result, the rotational speeds of the first coupling body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 become "0". Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes minus “Rvs” 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 mechanism rotates following the planetary gear mechanism that transmits power among the four planetary gear mechanisms 4 to 7.

  FIG. 3A is a diagram summarizing and displaying the relationship between the above-described shift speeds and the states of the clutches C1 and C2 and the brakes B1 to B3 as the engagement mechanisms. It represents that.

  3B, the gear ratio h of the first planetary gear mechanism 4 is 1.666, the gear ratio i of the second planetary gear mechanism 5 is 2.100, and the gear ratio j of the third planetary gear mechanism 6 is FIG. 3 (a) also shows the gear ratio of each gear stage (the rotational speed of the input shaft 2 / the rotational speed of the output member 3) when the gear ratio k of the 2,000 and fourth planetary gear mechanism 7 is 1.666. Yes. According to this, the public ratio (ratio of gear ratios between the gears) becomes appropriate, and the ratio orange (1st speed ratio / 8th speed ratio) shown in FIG. 3B is also appropriate.

  According to the automatic transmission of the first embodiment, eight forward speeds can be changed, and a total of five engagement mechanisms including two wet multi-plate clutches C1 and C2 and three wet multi-plate brakes B1 to B3. Of these, the two engagement mechanisms are engaged at each gear position. For this reason, the number of engagement mechanisms opened at each shift stage is three, and the friction loss due to the opened engagement mechanisms is reduced as compared with the conventional one where four engagement mechanisms are opened. The transmission efficiency of the automatic transmission can be improved.

  On the input shaft 2 (or a main shaft (not shown) that rotatably supports the input shaft 2), four planetary gear mechanisms 4 to 7 and two wet multi-plate clutches C1 and C2 are arranged. Six members are arranged. For this reason, the shaft length of the automatic transmission is shortened as compared with the conventional product in which a total of seven members including three planetary gear mechanisms and four wet multi-plate clutches are arranged on the axis of the input shaft 2. It is possible to improve the mountability to the FF type vehicle.

  Further, since all of the first to fourth planetary gear mechanisms 4 to 7 are constituted by a single pinion type planetary gear mechanism, each planetary gear mechanism 4 to 7 meshes with the sun gear and the ring gear and Compared to the case of a planetary gear mechanism of a double pinion type comprising a pair of pinions that mesh with the sun gear and the other mesh with the ring gear, and a carrier that rotatably and revolves, the input shaft 2 to the output member 3 The number of gear engagements in the power transmission path can be reduced, and transmission efficiency can be improved.

  In the first embodiment, the first wet multi-plate brake B1 is used as the first brake of the present invention. However, the first brake of the present invention is not limited to this. For example, a meshing mechanism such as a dog clutch or a synchromesh mechanism is used. A mechanism or a two-way clutch may be used. If comprised in this way, the friction loss in a 1st brake can be suppressed more in the forward 4th speed level-8th speed level in which a 1st brake will be in an open state, and the transmission efficiency of an automatic transmission will be improved more. be able to.

  When a two-way clutch is used as the first brake, a reverse rotation prevention state in which forward rotation (rotation in the direction in which the vehicle moves forward) is allowed and reverse rotation (rotation in the direction in which the vehicle moves backward) is prevented in the forward gear. In the reverse stage, it is sufficient to switch to a forward rotation prevention state that prevents forward rotation and allows reverse rotation.

  According to this, the controllability of the shift between the third speed and the fourth speed can be improved for the same reason as in the second embodiment using the 1-way clutch described later. Further, even when the 2-way clutch is in an open state in which the second coupling body Ra-Cb is not fixed to the transmission case 1, no friction loss occurs. For this reason, the friction loss can be further suppressed as the entire automatic transmission. Further, if the two-way clutch is switched to the forward rotation prevention state when the vehicle is in a decelerating state at the first to third forward speeds, the engine brake can be applied.

  In the first embodiment, the first to fourth planetary gear mechanisms 4 to 7 are configured by a single pinion type planetary gear mechanism. However, the first to fourth planetary gear mechanisms 4 to 7 are double pinion type planetary gear mechanisms. You may comprise.

[Second Embodiment]
Next, an automatic transmission according to a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same thing as 1st Embodiment. As shown in FIG. 4, the automatic transmission of the second embodiment is similar to that of the first embodiment in that the first to fourth planetary gear mechanisms 4 to 7 and the first and second two Wet multi-plate clutches C1 and C2 are provided.

  The second wet multi-plate clutch C2 is configured to be switchable between a connected state in which the first connecting member Ca-Rc-Rd and the second connecting member Ra-Cb are connected and an open state in which this connection is broken.

  The automatic transmission of the second embodiment includes a fourth wet multi-plate brake B4 and a 1-way clutch F1 in addition to the first to third wet multi-plate brakes B1 to B3 of the first embodiment. The fourth wet multi-plate brake B4 is configured to be switchable between a fixed state in which the 1-way clutch F1 is fixed to the transmission case 1 and an open state in which this fixing is released.

  Further, the 1-way clutch F1 rotates integrally with the second coupling body Ra-Cb when the second coupling body Ra-Cb rotates in the reverse direction (rotation in the direction in which the vehicle moves backward). When -Cb rotates forward (rotation in the direction in which the vehicle moves forward), it is configured not to rotate integrally with the second connector Ra-Cb but to be relatively rotatable. Other configurations are the same as those of the automatic transmission according to the first embodiment.

  In the automatic transmission according to the second embodiment, when the first gear is established, the first wet multi-plate clutch C1 is brought into a connected state and the fourth wet multi-plate brake B4 is brought into a fixed state. As a result, the first connected body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 rotate at the same speed.

  In addition, the 1-way clutch F1 is fixed to the transmission case 1, and the reverse rotation of the second connected body Ra-Cb is prevented by the action of the 1-way clutch F1, and the rotational speed of the second connected body Ra-Cb is " 0 ”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “1st” shown in FIG. 5, and the first gear is established.

  At the first speed, the first wet multi-plate brake B1 is released, but the rotational speed of the second coupling body Ra-Cb becomes “0” by the action of the 1-way clutch F1, so that friction loss occurs. do not do. Also, if the first wet multi-plate brake B1 is in the connected state at the first speed, the engine brake can be applied.

  When the second gear is established, the second wet multi-plate brake B2 and the fourth wet multi-plate brake B4 are fixed. As a result, the rotation speed of the second coupling body Ra-Cb becomes “0” by the action of the one-way clutch F1, and the rotation speed of the sun gear Sb (fourth element) of the second planetary gear mechanism 5 also becomes “0”. Thus, the fourth to sixth elements Sb, Cb, and Rb of the second planetary gear mechanism 5 are in a locked state in which relative rotation is impossible.

  For this reason, the rotational speed of the third coupled body Rb-Cc-Sd is also “0”, and the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 coupled to the output member 3 is “ 2nd ", the second gear is established.

  Note that, even at the second speed, the first wet multi-plate brake B1 is in the released state, but as with the first speed, the rotational speed of the second connected body Ra-Cb is “1” due to the action of the one-way clutch F1. “0”, no friction loss occurs. Even at the second speed, the engine brake can be applied if the first wet multi-plate brake B1 is in the connected state.

  When the third speed is established, the third wet multi-plate brake B3 and the fourth wet multi-plate brake B4 are set in a fixed state. As a result, the rotational speed of the second coupling body Ra-Cb becomes “0” by the action of the one-way clutch F1, and the rotational speed of the sun gear Sc (9th element) of the third planetary gear mechanism 6 also becomes “0”. . Then, the rotation speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “3rd” shown in FIG. 5, and the third speed stage is established.

  Note that, even at the third speed, the first wet multi-plate brake B1 is in the released state, but as with the first and second speeds, the rotational speed of the second connected body Ra-Cb is 1-way clutch F1. Because of this, it becomes “0”, so no friction loss occurs. Even at the third speed, if the first wet multi-plate brake B1 is in the connected state, the engine brake can be applied.

  When the fourth speed is established, the second wet multi-plate brake B2, the third wet multi-plate brake B3, and the fourth wet multi-plate brake B4 are fixed. As a result, the rotational speeds of the sun gear Sb (fourth element) of the second planetary gear mechanism 5 and the sun gear Sc (9th element) of the third planetary gear mechanism 6 become “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “4th” shown in FIG. 5, and the fourth speed stage is established.

  When the fifth gear is established, the first wet multi-plate clutch C1 is engaged, and the third wet multi-plate brake B3 and the fourth wet multi-plate brake B4 are fixed. As a result, the first coupling body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 rotate at the same speed, and the sun gear Sc (9th element) of the third planetary gear mechanism 6 rotates. The speed becomes “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “5th” shown in FIG.

  When the sixth speed is established, the second wet multi-plate clutch C2 is brought into a connected state, and the third wet multi-plate brake B3 and the fourth wet multi-plate brake B4 are brought into a fixed state. Thereby, since the carrier Ca (second element) and the ring gear Ra (third element) of the first planetary gear mechanism 4 rotate at the same speed, the first to third elements Sa and Ca of the first planetary gear mechanism 4 are rotated. , Ra are in a locked state where relative rotation is impossible, and the rotation speeds of the first to third elements Sa, Ca, Ra become “1”.

  Further, the rotational speed of the sun gear Sc (the ninth element) of the third planetary gear mechanism 6 becomes “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “6th” shown in FIG.

  When the seventh speed is established, the first wet multi-plate clutch C1 and the second wet multi-plate clutch C2 are connected, and the fourth wet multi-plate brake B4 is fixed. As a result, the first to third elements Sa, Ca, Ra of the first planetary gear mechanism 4 are brought into a locked state in which relative rotation is impossible, and the rotation speed of the first to third elements Sa, Ca, Ra is “1”. "become. Further, the rotational speeds of the first coupling body Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 are "1" which is the same speed.

  For this reason, all the elements of the planetary gear mechanisms 4 to 7 are locked so as not to be relatively rotatable, and the rotation speed of the carrier Cd (the eleventh element) of the fourth planetary gear mechanism 7 connected to the output member 3 is “1”. A certain “7th” is reached and the seventh gear is established.

  When the eighth speed is established, the second wet multi-plate clutch C2 is brought into a connected state, and the second wet multi-plate brake B2 and the fourth wet multi-plate brake B4 are brought into a fixed state. As a result, the first to third elements Sa, Ca, Ra of the first planetary gear mechanism 4 are brought into a locked state in which relative rotation is impossible, and the rotation speed of the first to third elements Sa, Ca, Ra is “1”. "become. Further, the rotational speed of the sun gear Sb (fourth element) of the second planetary gear mechanism 5 becomes “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes “8th” shown in FIG.

  When the reverse gear is established, the first wet multi-plate clutch C1 is brought into a connected state and the second wet multi-plate brake B2 is brought into a fixed state. Since the fourth wet multi-plate brake B4 is in the released state, the function of the one-way clutch F1 becomes invalid, and the second connected body Ra-Cb is allowed to reversely rotate.

  Further, the rotational speeds of the first connecting member Ca-Rc-Rd and the sun gear Sb (fourth element) of the second planetary gear mechanism 5 are equal, and the rotational speeds of both are “0”. Then, the rotational speed of the carrier Cd (11th element) of the fourth planetary gear mechanism 7 connected to the output member 3 becomes minus “Rvs” shown in FIG. 5, and the reverse gear is established.

  A speed line indicated by a dotted line in FIG. 5 indicates that each element of the other planetary gear mechanism rotates following the planetary gear mechanism that transmits power among the four planetary gear mechanisms 4 to 7.

  FIG. 6 is a diagram summarizing and displaying the relationship between the above-described shift speeds and the states of the clutches C1 and C2 and the brakes B1 to B4 and the one-way clutch F1 serving as the engagement mechanisms. "O" in the column of ~ B4 represents a connected state or a fixed state. Further, “◯” in the column of the 1-way clutch F1 indicates that the rotational speed of the second coupling body Ra-Cb is “0” due to the action of the 1-way clutch F1. Further, “(◯)” in the column of the first wet multi-plate brake B1 indicates that the engine brake is fixed when it is applied.

  Similarly to the first embodiment, the gear ratio h of the first planetary gear mechanism 4 is 1.666, the gear ratio i of the second planetary gear mechanism 5 is 2.100, and the gear ratio j of the third planetary gear mechanism 6 is 2. 000, and the gear ratio k of the fourth planetary gear mechanism 7 when the gear ratio k is 1.666 (the rotational speed of the input shaft 2 / the rotational speed of the output member 3) are also shown. According to this, the common ratio (ratio of gear ratios between the respective gears) becomes appropriate, and the ratio orange (1st speed ratio / 8 speed ratio) becomes appropriate.

  According to the automatic transmission of the second embodiment, the same effect as that of the first embodiment can be obtained. Further, in the automatic transmission of the second embodiment, when upshifting from the third gear to the fourth gear, it is only necessary to switch the second wet multi-plate brake B2 to the connected state, and from the fourth gear to the third gear. When downshifting to a high speed, it is only necessary to switch the second wet multi-plate brake B2 to the open state.

  Therefore, according to the automatic transmission of the second embodiment, the first and second two wet multi-plate brakes B1, B1 are used when shifting between the third gear and the fourth gear as in the first embodiment. Compared with the case where the state of B2 needs to be switched, the controllability of the shift between the third gear and the fourth gear can be improved.

  In addition, the first wet multi-plate brake B1 of the second embodiment can be switched to a fixed state only when the engine brake is applied at the first to third gears. Can be configured.

  Here, in the wet multi-plate brake, the friction loss increases in proportion to the increase in capacity. For this reason, according to the automatic transmission of the second embodiment, compared to the case where the wet multi-plate brake having a relatively large capacity is used in the fourth to eighth gears in which the second coupling body Ra-Cb rotates. The friction loss generated in the first wet multi-plate brake B1 can be reduced.

  Note that the automatic transmission of the second embodiment can obtain the same effects as those of the first embodiment even if the fourth wet multi-plate brake B4 and the one-way clutch F1 are omitted. Further, the second wet multi-plate clutch C2 can be switched between a connected state in which the sun gear Sa (first element) and the ring gear Ra (third element) of the first planetary gear mechanism 4 are connected, and an open state in which this connection is cut off. You may comprise.

  In the automatic transmission according to the second embodiment, a meshing mechanism such as a dog clutch or a synchromesh mechanism or a two-way clutch may be used instead of the first wet multi-plate brake B1 as in the first embodiment. . Further, the first to fourth planetary gear mechanisms 4 to 7 may be constituted by double pinion type planetary gear mechanisms.

DESCRIPTION OF SYMBOLS 1 ... Transmission case, 2 ... Input shaft, 3 ... Output member, 4 ... 1st planetary gear mechanism, Sa ... Sun gear (1st element), Ra ... Ring gear (3rd element), Pa ... Pinion, Ca ... Carrier (1st) 2 elements), 5 ... second planetary gear mechanism, Sb ... sun gear (fourth element), Rb ... ring gear (sixth element), Pb ... pinion, Cb ... carrier (fifth element), 6 ... third planetary gear mechanism, Sc ... Sun gear (9th element), Rc ... Ring gear (7th element), Pc ... Pinion, Cc ... Carrier (8th element), 7 ... 4th planetary gear mechanism, Sd ... Sun gear (12th element), Rd ... Ring gear ( 10th element), Pd ... pinion, Cd ... carrier (11th element), C1 ... first wet multi-plate clutch, C2 ... second wet multi-plate clutch, B1 ... first wet multi-plate brake, B2 ... second wet Multi-disc brake, B3 ... the third wet multi-disc brake, B4 ... fourth wet multi-disc brakes.

Claims (4)

An automatic transmission that is rotatably supported in a transmission case and that rotates the input shaft rotated by power from a drive source in multiple stages and outputs it 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 order of arrangement at intervals corresponding to the gear ratio in the velocity diagram,
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 velocity diagram,
The three elements of the third planetary gear mechanism are a seventh element, an eighth element, and a ninth element, respectively, in order of arrangement at intervals corresponding to the gear ratio in the velocity diagram,
The three elements of the fourth planetary gear mechanism are respectively arranged as a tenth element, an eleventh element, and a twelfth element in order of arrangement at intervals corresponding to the gear ratio in the velocity diagram.
The first element is connected to the input shaft, the eleventh element is connected to the output member, and the second element, the seventh element, and the tenth element are connected to form a first connection body. , The third element and the fifth element are connected to form a second connecting body, the sixth element, the eighth element, and the twelfth element are connected to form a third connecting body,
A first wet multi-plate clutch that is switchable between a connected state for connecting the first connecting body and the fourth element and an open state for disconnecting the connection;
A second wet multi-plate clutch that can be switched between a connected state in which any two of the first to third elements of the first planetary gear mechanism are connected to each other and an open state in which the connection is broken;
A first brake switchable between a fixed state in which the second connector is fixed to the transmission case and an open state in which the fixing is released;
A second brake switchable between a fixed state for fixing the fourth element to the transmission case and an open state for releasing the fixing;
An automatic transmission comprising: a third brake that can be switched between a fixed state in which the ninth element is fixed to the transmission case and an open state in which the ninth element is released. The automatic transmission according to claim 1, wherein
A one-way clutch that rotates integrally with the second coupling body is provided only when the second coupling body reverses,
4. An automatic transmission comprising a fourth brake capable of switching between a fixed state in which the one-way clutch is fixed to the transmission case and an open state in which the fixing is released. The automatic transmission according to claim 1, wherein
The first brake is switchable between a reverse rotation preventing state in which forward rotation of the second connected body is allowed and reverse rotation is prevented, and a forward rotation preventing state in which forward rotation of the second connected body is allowed and reverse rotation is allowed. An automatic transmission comprising a two-way clutch. The automatic transmission according to any one of claims 1 to 3,
The four planetary gear mechanisms are constituted by a single pinion type planetary gear mechanism including 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. Automatic transmission.

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