Patent Application
20130340567
The present invention relates to a dual-clutch-type vehicle transmission that is provided with two input shafts coupled to a motive-power source via friction clutches and one output shaft engaged with the input shafts via a speed-changing gear mechanism(s) and starts moving while controlling the coupled state of the two friction clutches.
In a conventional dual-clutch-type vehicle transmission, for example, the techniques of Patent Literature 1 have been proposed as a method of reducing speed-changing shock upon start of moving of a vehicle when large torque is input to the transmission.
A twin-clutch-type transmission described in Patent Literature 1 is configured so as to individually control the coupled state of two friction clutches upon start of moving so that the torque transmitting capacity by both of the friction clutches becomes a capacity necessary for starting moving.
However, in the configuration described in Patent Literature 1, upon start of moving, first, coupling of a first friction clutch which transmits torque to a first speed level of a speed-changing gear mechanism is started; after a predetermined period of time elapses, reduction of a torque transmitting capacity is started before the first friction clutch completes coupling; and, the amount corresponding to the reduction is shared by a second friction clutch which transmits torque to a second speed level; wherein, the sum of the maximum torque transmitting capacities of both of the friction clutches is not effectively used.
Moreover, since both of gear rows of the first speed level and the second speed level having different gear ratios are engaged upon start of moving, it is difficult to control distribution of torque with respect to the friction clutches. Furthermore, upon start of moving, coupling and release of the first friction clutch and coupling of the second friction clutch is carried out while sliding both of the friction clutches; therefore, there are problems such as temporal deterioration in torque transmitting efficiency and excessive wear of clutch plates.
The present invention has been accomplished in order to solve the above described problems, and it is an object to provide a dual-clutch-type vehicle transmission capable of reducing the maximum torque transmitting capacity of each of friction clutches by transmitting torque to a first speed level of a speed-changing gear mechanism by coupling both of a first friction clutch and a second friction clutch upon start of moving.
Moreover, it is another object to provide a dual-clutch-type vehicle transmission which does not deteriorate torque transmitting efficiency and does not excessively wear clutch plates by carrying out coupling without sliding the friction clutches when both of the first friction clutch and the second friction clutch are coupled.
In order to achieve these objects, a dual-clutch-type vehicle transmission according to the present invention is configured in a below manner. First, the present invention is directed to a dual-clutch-type vehicle transmission having: a first input shaft and a second input shaft; a first friction clutch that can transmit motive power from a motive-power source to the first input shaft; a second friction clutch that can transmit the motive power from the motive-power source to the second input shaft; a speed-changing gear mechanism that can select any one level of a plurality of speed changing levels to carry out speed change by connecting/disconnecting the motive power from the first input shaft and the second input shaft; and an output shaft that outputs the motive power from the speed-changing gear mechanism.
In such a dual-clutch-type vehicle transmission, in the present invention, the speed-changing gear mechanism is provided with a shared gear that can connect the first input shaft and the second input shaft at the same time. The shared gear is characterized by being disposed to be coaxial with the first input shaft and the second input shaft.
Herein, the dual-clutch-type vehicle transmission of the present invention is characterized in that, upon start of moving of a vehicle, in a state that a first speed level is selected by the speed-changing gear mechanism, the first friction clutch and the second friction clutch are coupled at the same time at equal to or higher than a maximum value or an intermediate value of a torque transmitting capacity, and the motive power from the motive-power source can be transmitted to the output shaft via the first friction clutch and the second friction clutch.
Alternatively, the dual-clutch-type vehicle transmission of the present invention is characterized in that, upon start of moving of a vehicle, in a state that a first speed level is selected by the speed-changing gear mechanism, after either one of the first friction clutch and the second friction clutch is coupled, the other one is coupled, and the motive power from the motive-power source can be transmitted to the output shaft.
Moreover, the speed-changing gear mechanism has: a plurality of gear rows that constitute the plurality of speed-changing levels; a first switching clutch that can select any one row of the plurality of gear rows and connect to the first input shaft; and a second switching clutch that can select any one row of the plurality of gear rows and connect to the second input shaft.
Furthermore, the speed-changing gear mechanism may have a first speed-changing gear mechanism that can carry out speed change by selecting any one level of the plurality of speed changing levels including at least a first speed level by the first switching clutch; and a second speed-changing gear mechanism that can carry out speed change by selecting any one level of the plurality of speed changing levels including at least a second speed level by the second switching clutch.
That case is provided with a third switching clutch that can select any one of low speed levels including the first speed level and the second speed level and a high speed level including at least a highest speed level and transmit the motive power to the output shaft, the motive power having undergone speed change by the first speed-changing gear mechanism or the second speed-changing gear mechanism.
According to the present invention, upon start of moving of the vehicle when large torque is input to the transmission, the maximum torque transmitting capacities of the friction clutches can be reduced by coupling both of the first friction clutch and the second friction clutch and transmitting torque from both of the friction clutches to the first speed level of the speed-changing gear mechanism.
Moreover, the first friction clutch and the second friction clutch are coupled without sliding; therefore, the torque transmitting efficiency of the transmission is not deteriorated, and excessive wear and damage of clutch plates can be prevented.
Moreover, the timing of coupling of the first friction clutch and the second friction clutch is mutually shifted; therefore, a half clutch effect can be obtained.
Furthermore, the speed-changing gear mechanism achieves the first speed level by connecting both of the first input shaft and the second input shaft; therefore, the first speed level can be shifted to any of the second speed level at which it is connected to the first input shaft and the third speed level at which it is connected to the second input shaft.
Hereinafter, a dual-clutch-type vehicle transmission of the present invention will be explained based on drawings showing outlines of an embodiment.
In
Motive power from a motive-power source 8 is input to the first input shaft 21 via a first friction clutch 11, the motive power from the motive-power source 8 is input to the second input shaft 22 via a second friction clutch 12, and speed-changed motive power is output from an output shaft 27 via the intermediate shaft 24.
A first input gear (shared gear) 43 is rotatably provided at the first input shaft 21, and the first input gear 43 is connected/disconnected to/from the first input shaft 21 by a first switching clutch 31 and is connected/disconnected to/from the second input shaft 22 by a second switching clutch 32.
In the present embodiment, the first friction clutch 11 and the second friction clutch 12 are dry-type single plate clutches, but may employ a different type such as wet-type multi-plate clutches. The first switching clutch 31 and the second switching clutch 32 are engagement clutches provided with general synchronization mechanisms, but may employ a different type.
A first intermediate gear 44, a second intermediate gear 54, a third intermediate gear 64, and a fourth intermediate gear 74 are fixedly provided at the intermediate shaft 24 to constitute a first gear row 40, in which the first input gear 43 and the first intermediate gear 44 are engaged with each other, a second gear row 50, in which a second input gear 51 and the second intermediate gear 54 are engaged with each other, and a third gear row 60, in which a third input gear 62 and the third intermediate gear 64 are engaged with each other.
A speed-changing gear mechanism 30 functions when the first switching clutch 31 and the second switching clutch 32 select and connect these gear rows to transmit the motive power undergone speed changing to a first speed level by the first gear row 40, a second speed level by the second gear row 50, and a third speed level by the third gear row 60 to the intermediate shaft 24.
Furthermore, a fourth intermediate gear 74 fixed to the intermediate shaft 24 and an output gear 77 fixed to the output shaft 27 are engaged with each other to constitute an output gear row 70 and transmit the motive power from the speed-changing gear mechanism 30 to the output shaft 27.
In
Upon start of moving of the vehicle, in this state, first, the first input shaft 21 and the first input gear 43 are connected to each other by the first switching clutch 31, the second input shaft 22 and the first input gear 43 are connected to each other by the second switching clutch 32 to obtain the state of the first speed level in which the first gear row 40 is selected; and, then, both of the first friction clutch 11 and the second friction clutch 12 are coupled.
In
Herein, the motive power from the motive-power source 8 transmitted through a path via the first friction clutch 11, the first input shaft 21, and the first switching clutch 31 and a path via the second friction clutch 12, the second input shaft 22, and the second switching clutch 32 is merged by the first input gear 43, is subjected to speed-change to the first speed level by the first gear row 40, and is output from the output shaft 27 via the intermediate shaft 24 and the output gear row 70.
The coupling of the first friction clutch 11 and the second friction clutch 12 upon start of moving of the vehicle is basically carried out at the same time by a maximum value of a torque transmitting capacity. However, if driving wheels slip due to, for example, the state of a road surface on which the vehicle is running, the torque transmitting capacity can be arbitrarily reduced, and slippage of the driving wheels can be avoided by practically making an adjustment within a range from a zero value of the torque transmitting capacity to the maximum value.
After either one of the first friction clutch 11 and the second friction clutch 12 is coupled, the other one may be coupled. In that case, either one of a method in which, after coupling of the friction clutch that has started coupling first is completed, coupling of the other friction clutch is started and a method in which, before coupling of the friction clutch that has started coupling first is completed, coupling of the other friction clutch is started can be employed.
In
At this point, the second friction clutch 12 is still coupled. Therefore, the motive power from the motive-power source 8 is transmitted to the output shaft 27 via the second input shaft 22, the second switching clutch 32, the first gear row 40, and the output gear row 70. Then, when coupling of the first friction clutch 11 and releasing of the second friction clutch 12 are carried out at the same time, it is switched to the second speed level using intermediation of the second gear row 50.
In
In
Therefore, the second switching clutch 32 is in a state in which the third gear row 60 is selected. Then, when releasing of the first friction clutch 11 and coupling of the second friction clutch 12 are carried out at the same time, it is switched to the third speed level using intermediation of the third gear row 60.
In
In
At this point, the first friction clutch 11 is still coupled. Therefore, the motive power from the engine 8 is transmitted to the output shaft 27 via the first input shaft 21, the first switching clutch 31, the first gear row 40, and the output gear row 70. Then, when releasing of the first friction clutch 11 and coupling of the second friction clutch 12 are carried out at the same time, it is switched to the third speed level using intermediation of the third gear row 60.
In
Herein, marks O represent a state in which the friction/switching clutch is coupled/connected to transmit torque, marks Δ represent a state in which the switching clutch is connected but is not transmitting torque, and marks X represent a state in which the friction/switching clutch is released/disconnected and is not transmitting torque.
In
Motive power from the motive-power source 8 is input to the first input shaft 121 via a first friction clutch 111, the motive power from the motive-power source 8 is input to the second input shaft 122 via a second friction clutch 112, and speed-changed motive power is output from an output shaft 127 via the intermediate shaft 124.
A first input gear 143 and a third input gear 151 are rotatably provided at the first input shaft 121 and are connected/disconnected to/from the first input shaft 121 by a first switching clutch 131, and a second input gear 172 and a fourth input gear 183 are rotatably provided at the second input shaft 122 and are connected/disconnected to/from the second input shaft 122 by a second switching clutch 162. The first input gear 143 and the fourth input gear 183 are coupled by a first shared shaft 123 and are integrally rotated as a shared gear.
A first intermediate gear 145 and a third intermediate gear 155, which are coupled by a second shared shaft 125 and integrally rotated, and a second intermediate gear 176 and a fourth intermediate gear 186, which are coupled by a third shared shaft 126 and integrally rotated, are rotatably provided at the intermediate shaft 124 and are connected/disconnected to/from the intermediate shaft 124 by a third switching clutch 204.
Herein, a first gear row 140, in which the first input gear 143 and the first intermediate gear 145 are engaged with each other; a third gear row 150, in which the third input gear 151 and the third intermediate gear 155 are engaged with each other; and the first switching clutch 131 constitutes a first speed-changing gear mechanism 130. A second gear row 170, in which the second input gear 172 and the second intermediate gear 176 are engaged with each other; a fourth gear row 180, in which the fourth input gear 183 and the fourth intermediate gear 186 are engaged with each other; and the second switching clutch 162 constitutes a second speed-changing gear mechanism 160.
A fifth intermediate gear 194 fixed to the intermediate shaft 124 and an output gear 197 fixed to the output shaft 127 are engaged with each other to constitute an output gear row 190 and transmits the motive power from the first speed-changing gear mechanism 130 or the second speed-changing gear mechanism 160, which is selected by the third switching clutch 204, to the output shaft 127.
In
Upon start of moving of the vehicle, in this state, first, the first input shaft 121 and the first input gear 143 are connected to each other by the first switching clutch 131, and the second input shaft 122 and the third input gear 183 are connected to each other by the second switching clutch 162 so as to obtain the state of the first speed level in which the first gear row 140 is selected. Then, both of the first friction clutch 111 and the second friction clutch 112 are coupled.
In
Herein, the motive power from the motive-power source 8 transmitted by a path via the first friction clutch 111, the first input shaft 121, and the first switching clutch 131 and a path via the second friction clutch 112, the second input shaft 122, and the second switching clutch 162 is merged by the first input gear 143, is subjected to speed-change to the first speed level by the first gear row 140, and is output from the output shaft 127 via the intermediate shaft 124 and the output gear row 190.
The switching of the motive-power transmitting paths of the transmission 110 shown in
The switching operation of the transmission 110 from the first speed level to the third speed level is basically the same as that of the embodiment shown in
Herein, marks O represent a state in which the friction/switching clutch is coupled/connected to transmit torque, marks Δ represent a state in which the switching clutch is connected but is not transmitting torque, and marks X represent a state in which the friction/switching clutch is released/disconnected and is not transmitting torque.
In
The motive power from the motive-power source 8 is input to the first input shaft 221 via a first friction clutch 211, the motive power from the motive-power source 8 is input to the second input shaft 222 via a second friction clutch 212, and speed-changed motive power is output from an output shaft 227 via the intermediate shaft 224.
A first input gear 243 and a third input gear 251 are rotatably provided at the first input shaft 221 and are connected/disconnected to/from the first input shaft 221 by a first switching clutch 231, and a second input gear 272 and a fourth input gear 283 are rotatably provided at the second input shaft 222 and are connected/disconnected to/from the second input shaft 222 by a second switching clutch 262. The first input gear 243 and the fourth input gear 283 are coupled by a first disconnection/connection clutch 223 and are integrally rotated as a shared gear.
A first intermediate gear 245 and a third intermediate gear 255, which are coupled by a disconnection/connection clutch 225 and integrally rotated, and a second intermediate gear 276 and a fourth intermediate gear 286, which are coupled by a third disconnection/connection clutch 226 and integrally rotated, are rotatably provided at the intermediate shaft 224; and the intermediate shaft 224 is connected/disconnected by the second disconnection/connection clutch 225 and the third disconnection/connection clutch 226.
Herein, a first gear row 240, in which the first input gear 243 and the first intermediate gear 245 are engaged with each other; a third gear row 250, in which the third input gear 251 and the third intermediate gear 255 are engaged with each other; and the first switching clutch 231 constitute a first speed-changing gear mechanism 230. A second gear row 270, in which the second input gear 272 and the second intermediate gear 276 are engaged with each other; a fourth gear row 280, in which the fourth input gear 283 and the fourth intermediate gear 286 are engaged with each other; and the second switching clutch 262 constitute a second speed-changing gear mechanism 260.
A fifth intermediate gear 294 fixed to the intermediate shaft 224 and an output gear 297 fixed to the output shaft 227 are engaged with each other to constitute an output gear row 290 and transmit the motive power from the first speed-changing gear mechanism 230 or the second speed-changing gear mechanism 260 selected by the second disconnection/connection clutch 225 and the third disconnection/connection clutch 226 to the output shaft 227.
In
Upon start of moving of the vehicle, in this state, first, the first input shaft 221 and the first input gear 243 are connected by the first switching clutch 231, and the second input shaft 222 and the third input gear 283 are connected by the second switching clutch 262 to obtain the state of the first speed level in which the first gear row 240 is selected. Then, both of the first friction clutch 211 and the second friction clutch 212 are coupled.
In
The motive power from the motive-power source 8 transmitted by a path via the first friction clutch 211, the first input shaft 221, and the first switching clutch 231 and a path via the second friction clutch 212, the second input shaft 222, and the second switching clutch 262 is merged by the first input gear 243, is subjected to speed-change to the first speed level by the first gear row 240, and is output from the output shaft 227 via the intermediate shaft 224 and the output gear row 290.
The switching of the motive-power transmitting paths of the transmission 210 shown in
The switching operation of the transmission 210 from the first speed level to the third speed level is basically the same as that of the embodiment shown in
Herein, marks O represent a state in which the friction/switching/disconnection/connection clutch is coupled/connected to transmit torque, marks Δ represent a state in which the switching/disconnection/connection clutch is connected but is not transmitting torque, and marks X represent a state in which the friction/switching/disconnection/connection clutch is released/disconnected and is not transmitting torque.
In the above described embodiment, upshifts like the first speed level to the second speed level have been explained. In a downshift like speed-change from the second speed level to the first speed level, a speed changing operation can be carried out by carrying out operations opposite to the explanation of the upshift.
The explanations of the embodiments are finished above. However, the present invention is not limited to the above described embodiments, include arbitrary modifications that do not impair objects and advantages thereof, and is not limited by numerical values, etc. shown in the above described embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-016257 | Jan 2011 | JP | national |
| 2012-010852 | Jan 2012 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/051649 | Jan 2012 | US |
| Child | 13951701 | US |
