JP2013194910A - Dual clutch type automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dual clutch type automatic transmission capable of cooling a dual clutch using a shift stage gear at a non-traveling side when a temperature of the dual clutch becomes a set temperature or higher.SOLUTION: A duel clutch type automatic transmission includes: a clutch temperature derivation part 23b that derives a temperature of a dual clutch; and a clutch temperature determination part S102 that determines whether or not the clutch temperature derived by the clutch temperature derivation part becomes higher than a set temperature that has been previously set, and also includes a non-traveling side gear switching part S110 that switches an odd number shift stage gear or an even number shift stage gear at the non-traveling side to a low speed stage side when the clutch temperature determination part determines that the clutch temperature is the set temperature or higher, and controls so that the rotation speed of the clutch 20a or 20b in a disconnected state is increased.

Description

  The present invention relates to a dual clutch type automatic transmission that can cool a dual clutch by using a non-travel side shift gear when the temperature of the dual clutch becomes equal to or higher than a set temperature.

  As a kind of vehicle transmission, a dual clutch having two clutches, two input shafts connected to these clutches, and a rotational driving force transmitted to one input shaft are shifted to establish an odd gear. There is a dual clutch type automatic transmission that includes a first shift mechanism and a second shift mechanism that shifts the rotational driving force transmitted to the other input shaft to establish an even-numbered shift stage. Such an automatic transmission has an advantage that a gear shifting operation can be performed without interrupting torque by controlling engagement switching with two clutches. As this type of dual clutch automatic transmission, for example, the one described in Patent Document 1 is known.

JP 2010-196745 A

  By the way, in the dual clutch type automatic transmission, the clutch is controlled to a half-clutch state at the time of shifting, and slipping occurs, so that the clutch generates heat. When the clutch generates heat, each member such as the clutch disk that composes the clutch thermally expands, or the friction coefficient of the clutch disk changes, and the clutch characteristics change. Even if it is operated, there is a risk that clutch control may be adversely affected, such as failure to obtain the desired clutch torque.

  The present invention has been made in view of the above-described conventional problems, and when the temperature of the dual clutch becomes equal to or higher than the set temperature, the non-traveling side shift gear is switched to the low speed side, thereby It is an object of the present invention to provide a dual clutch type automatic transmission capable of cooling the dual clutch by increasing the rotational speed of the clutch disk of the clutch to accelerate the movement of the fluid in the clutch housing.

  In order to solve the above-mentioned problem, a feature of the invention according to claim 1 is that a first input shaft and a second input shaft arranged concentrically, and a first clutch that transmits a rotational driving force of a prime mover to the first input shaft. And a second clutch that transmits the rotational driving force to the second input shaft, and a first shift that shifts the rotational driving force transmitted to the first input shaft and establishes an odd gear. A transmission having a mechanism and a second shift mechanism that shifts the rotational driving force transmitted to the second input shaft to establish an even-numbered shift stage; a clutch temperature deriving unit that derives the temperature of the dual clutch; A clutch temperature determination unit that determines whether or not the clutch temperature derived by the clutch temperature deriving unit is higher than a preset set temperature, and the clutch temperature is determined by the clutch temperature determination unit. When it is determined that the temperature is equal to or higher than a certain temperature, the odd-numbered gear or non-traveling gear on the non-traveling side is switched to the low-speed side, and control is performed to increase the rotational speed of the clutch in the disconnected state. And a side gear switching unit.

  According to a second aspect of the present invention, the clutch temperature deriving unit according to the first aspect is calculated based on an ambient temperature outside the dual clutch based on a heat generation temperature calculated based on a work amount of the dual clutch. That is, the clutch temperature estimation unit estimated by subtracting the heat radiation temperature is used.

  A feature of the invention according to claim 3 is that, in claim 1 or claim 2, the dual clutch is constituted by a dry clutch.

  According to the first aspect of the present invention, when the clutch temperature determining unit determines that the clutch temperature is equal to or higher than the set temperature, the non-traveling side odd-numbered gear or even-numbered gear is switched to the low speed side, and the disconnected state And a non-traveling side gear switching unit that controls to increase the rotational speed of the clutch.

  With this configuration, the movement of the fluid in the clutch housing is accelerated by the disconnected clutch, so that the temperature increase of the dual clutch can be suppressed, and each member such as the clutch disk is thermally expanded due to the heat generated by the clutch, Alternatively, adverse effects on the clutch control due to the change in the friction coefficient of the clutch disk can be reduced.

  According to the invention of claim 2, the clutch temperature deriving unit is estimated by subtracting the heat release temperature calculated based on the ambient temperature outside the dual clutch from the heat generation temperature calculated based on the work of the dual clutch. Since the clutch temperature estimation unit is used, the clutch temperature can be stably estimated over a long period of time as compared with a method in which the clutch temperature is directly detected using a sensor.

  According to the invention of claim 3, since the dual clutch is constituted by a dry clutch, the movement of the air in the clutch housing can be accelerated by increasing the rotational speed of the clutch in the disconnected state, which is simple. The clutch can be effectively cooled by the configuration.

1 is a diagram showing a vehicle equipped with a dual clutch type automatic transmission according to an embodiment of the present invention. 1 is a skeleton diagram showing an overall structure of a dual clutch type automatic transmission showing an embodiment of the present invention. It is sectional drawing which shows an example of a dual clutch. It is a figure which shows the time chart at the time of transmission control. It is a figure which shows the flowchart which controls a transmission according to clutch temperature. It is a diagram which shows transition of the temperature of a dual clutch.

  Hereinafter, a dual clutch automatic transmission (DCT) 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram in which a dual clutch automatic transmission 10 is applied to an FF (front engine / front drive) type vehicle. In addition to the dual clutch automatic transmission 10, the vehicle includes an engine 11 driven by combustion of gasoline, which is an example of a prime mover, a differential (differential) 13, left and right drive shafts 15a and 15b, and drive wheels. Left and right front wheels 16a and 16b.

  The rotational speed Ne of the engine 11 is detected by an engine rotational speed sensor 90 provided close to the drive shaft 12 of the engine 11. The accelerator operation amount when the accelerator pedal 91 is depressed is detected by the accelerator opening sensor 92 as the accelerator opening. An ECU (Engine Control Unit) 14 that controls the operation of the engine 11 receives information on the engine speed Ne, information on the accelerator opening, and various types of information from a TCU (Transmission Control Unit) 23 that controls the shift of the automatic transmission 10. The engine speed Ne and the engine torque are controlled by the engine control unit 14a by controlling the accelerator opening and the fuel injection amount based on the acquired information.

  The automatic transmission 10 is disposed on a power transmission path between the engine 11 and the differential 13 and shifts the rotation of the first and second input shafts 31a and 31b to a gear ratio of a plurality of stages to change the left and right front wheels 16a. , 16b, and a clutch 20 that engages and disengages the drive shaft 12 of the engine 11 and the input shaft 31 of the transmission 17. The clutch 20 is a dual clutch having a first clutch 20a that transmits the drive torque of the drive shaft 12 output from the engine 11 to the first input shaft 31a and a second clutch 20b that transmits the second input shaft 31b. It is configured.

  The rotational speeds N1 and N2 of the first input shaft 31a and the second input shaft 31b are detected by the first input shaft rotational speed sensor 93a and the second input shaft rotational speed sensor 93b, respectively. The wheel speeds of the left and right front wheels 16a and 16b and the left and right rear wheels (not shown) are detected by wheel speed sensors 94a and 94b, and these pieces of information are sent to the TCU 23. A vehicle speed (vehicle speed) is calculated based on the rotational speed of each wheel detected by the wheel speed sensors 94a and 94b.

  When the driver operates the shift lever 95, the shift position information is detected by the shift position sensor 96. The ECU 14 and the TCU 23 can exchange information with each other by CAN (Controller Area Network) communication. The TCU 23 includes a shift control unit 23a and a clutch temperature estimation unit 23b. The shift control unit 23a switches a plurality of shift gears based on information on the shift position detected by the shift position sensor 96, a shift command from the ECU 14, acquired vehicle information, and the like, as well as the first clutch 20a and the second clutch 20a. The clutch 20b is engaged and disengaged, and the shift control of the automatic transmission 10 is performed.

  The clutch temperature estimation unit 23 b estimates the temperature of the dual clutch 20 using a predetermined calculation formula stored in the TCU 23 based on the work amount of the dual clutch 20. Specifically, the clutch temperature estimation unit 23b integrates the heat generation temperature according to the amount of work performed by the dual clutch 20, and determines the temperature difference between the ambient temperature outside the dual clutch 20 and the temperature inside the dual clutch 20, or the vehicle. The heat dissipation temperature is integrated based on the speed. Then, the current temperature of the dual clutch 20 is estimated by subtracting (TA-TB) the value TB obtained by integrating the heat radiation temperature from the value TA obtained by integrating the heat generation temperature.

  The first and second clutches 20a and 20b of the dual clutch 20 are dry friction clutches. The engagement of the first clutch 20a is controlled by a first clutch actuator 25a having a motor as a drive source, and the second clutch 20b is engaged by a second clutch actuator 25b having a motor as a drive source. Are controlled together. The first and second clutch actuators 25a and 25b have stroke sensors 26a and 26b that detect the stroke amounts of the clutch actuators 25a and 25b, respectively. The clutch torque Tc of the first and second clutches 20 a and 20 b is controlled according to the stroke amount of the clutch actuator 25.

  The clutch temperature T0 estimated by the clutch temperature estimator 23b of the TCU 23 is constantly monitored by the TCU 23, and if the monitored clutch temperature is higher than a predetermined set temperature (threshold) T01, as described later, Control for suppressing heat generation of the clutch 20 is performed.

  As shown in FIG. 2, the dual clutch type automatic transmission 10 includes a forward gear 7 and a reverse gear 1. The dual clutch type automatic transmission 10 includes a dual clutch 20, a first input shaft 31 a and a second input shaft 31 b, a first counter shaft 35 and a second counter shaft 36. The first input shaft 31a has a rod shape, and the second input shaft 31b has a cylindrical shape and is coaxially arranged to be rotatable. The left side of the first input shaft 31a in the drawing is connected to the first clutch 20a of the dual clutch 20, and the left side of the second input shaft 31b in the drawing is connected to the second clutch 20b of the dual clutch 20. The first input shaft 31a and the second input shaft 31b are independently transmitted with torque and can be rotated at different rotational speeds. The first countershaft 35 is disposed on the lower side in the drawing in parallel with the input shafts 31 a and 31 b, and the second subshaft 36 is disposed on the upper side in the drawing in parallel with the input shaft 31.

  On the first input shaft 31a, a plurality of odd-speed drive gears, such as a first speed drive gear 51, a third speed drive gear 53, a fifth speed drive gear 55, and a seventh speed drive gear 57, are formed directly or fixed separately. Is provided. The second input shaft 31b is provided with a plurality of even-speed drive gears 52, a second speed drive gear 52 and a 4-6 speed drive gear 54, which are directly formed or separately fixed.

  The first countershaft 35 is provided with first, third, and fourth-speed driven gears 61, 63, and 64, respectively, so that the first-speed driven gear 61 and the third-speed driven gear 63 can rotate. Is meshed with the third speed drive gear 53, and the fourth speed driven gear 64 is meshed with the 4-6 speed drive gear 54, respectively.

  The second countershaft 36 is provided with second, fifth, sixth and seventh speed driven gears 62, 65, 66 and 67 so as to be freely rotatable, and the second speed driven gear 62 is connected to the second speed drive gear 52, The 5-speed driven gear 65 is engaged with the 5-speed drive gear 55, the 6-speed driven gear 66 is engaged with the 4-6-speed drive gear 54, and the 7-speed driven gear 67 is engaged with the 7-speed drive gear 57, respectively.

  The first countershaft 35 is provided with a reverse gear 70 so as to be freely rotatable, and the reverse gear 70 is always meshed with the small-diameter gear 62 b of the second speed driven gear 62.

  On the first countershaft 35 and the second countershaft 36, first, second, third, and fourth gear shift clutches 71 to 74 having a synchromesh function are provided. These gear shift clutches 71 to 74 are connected to the TCU 23. It is selectively operated by a shift control unit.

  The first gear shift clutch 71 is provided on the first countershaft 35 and is disposed between the synchro gear portion of the first speed driven gear 61 and the synchro gear portion of the third speed driven gear 63. By sliding the sleeve of the first gear shift clutch 71 in the axial direction, one of the first-speed driven gear 61 and the third-speed driven gear 63 and the first countershaft 35 are connected so as not to rotate relative to each other. The gears 61 and 63 are configured to be in a neutral state where they are not connected.

  Similarly, the second gear shift clutch 72 provided on the first countershaft 35 is disposed between the synchro gear portion of the 4-speed driven gear 64 and the synchro gear portion of the reverse gear 70, and the second gear shift clutch. By sliding the sleeve 72 in the axial direction, one of the fourth speed driven gear 64 and the reverse gear 70 and the first countershaft 35 are connected so as not to be relatively rotatable. The third gear shift clutch 73 provided on the second countershaft 36 is disposed between the synchro gear portion of the seventh-speed driven gear 67 and the synchro gear portion of the fifth-speed driven gear 65. By sliding the sleeve in the axial direction, one of the seventh speed driven gear 67 and the fifth speed driven gear 65 and the second countershaft 36 are connected so as not to be relatively rotatable. Further, the fourth gear shift clutch 74 provided on the second countershaft 36 is disposed between the synchro gear portion of the 6th speed driven gear 66 and the synchro gear portion of the 2nd speed driven gear 62, and the fourth gear shift clutch. By sliding the sleeve 74 in the axial direction, one of the sixth speed driven gear 66 and the second speed driven gear 62 and the second countershaft 36 are connected so as not to be relatively rotatable.

  The first and third gear shift clutches 71 and 73 described above constitute a first shift mechanism that shifts the rotational driving force transmitted to the first input shaft 31 to establish an odd gear, and the second and fourth gear shifts. The clutches 72 and 74 constitute a second shift mechanism that shifts the rotational driving force transmitted to the second input shaft 32 to establish an even-numbered shift stage.

  A final reduction drive gear 58 and a final reduction drive gear 59 are fixed to the first countershaft 35 and the second countershaft 36, respectively. These final reduction drive gears 58 and 59 are connected to the differential device 13 (see FIG. 1). It is always meshed with the reduction driven gear 80 on the connected shaft 33. Accordingly, the left and right front wheels 16a and 16b are driven via the final reduction drive gear 58 and the final reduction drive gear 59.

  The transmission 17 and the dual clutch 20 of the automatic transmission 10 described above include the accelerator opening, the rotational speed Ne of the drive shaft 12 of the engine 11, the rotational speeds N1 and N2 of the input shafts 31a and 31b of the automatic transmission 10, and the vehicle speed. It is actuated based on a command from the shift control unit 23a of the TCU 23 according to the traveling state of the vehicle. When the vehicle is stopped, the first to fourth gear shift clutches 71 to 74 of the transmission 17 are in the neutral position, and the engagements of the first and second clutches 20a and 20b of the dual clutch 20 are both released.

  Now, for example, in a state where the vehicle is traveling at the third speed, the accelerator control opening 23a of the TCU 23 is changed to a state suitable for the fourth speed when the accelerator opening is increased or the like. By operating the two-gear shift clutch 72, the first countershaft 35 and the fourth-speed driven gear 64 are connected, and a command for forming a fourth-speed gear stage is sent to the automatic transmission 10. After the fourth speed is established, the dual clutch 20 is switched from the first clutch 20a side to the second clutch 20b side and the first gear shift clutch 71 is returned to the neutral position based on a command from the TCU 23. .

  FIG. 3 shows an example of the detailed structure of the dual clutch 20. The dual clutch 20 has a clutch housing 20c. A center plate 20c1 is formed in the center of the clutch housing 20c in the axial direction, and the first clutch 20a and the second clutch 20b are arranged on both sides of the center plate 20c1. ing.

  The first clutch 20a is mainly composed of a first clutch disk 20a1, a first pressure plate 20a2, and a first diaphragm spring 20a3, and the second clutch 20b is mainly composed of a second clutch disk 20b1, a second pressure plate 20b2, It is comprised by the 2nd diaphragm spring 20b3.

  The first clutch disk 20a1 transmits the rotational driving force of the engine 11 to the first input shaft 31a, and the second clutch disk 20b1 transmits the rotational driving force of the engine 11 to the second input shaft 31b. The first clutch disk 20a1 is spline-engaged with the shaft end of the first input shaft 31a so as to be movable in the axial direction, and the second clutch disk 20b1 is movable with the shaft end of the second input shaft 31b in the axial direction. The spline is engaged.

  The center plate 20c1 is disposed between the first clutch disk 20a1 and the second clutch disk 20b1 so that both surfaces thereof face each other in parallel with the first and second clutch disks 20a1 and 20b1. The center plate 20c1 is provided to be rotatable relative to the second input shaft 31b via a ball bearing between the center plate 20c1 and the outer peripheral surface of the second input shaft 31b. The clutch housing 20 c is connected to the drive shaft 12 of the engine 11 and rotates integrally with the drive shaft 12 of the engine 11.

  The first and second pressure plates 20a2 and 20b2 sandwich the first and second clutch disks 20a1 and 20b1 with the center plate 20c1, respectively, and are arranged so as to be crimped to the first and second clutch disks 20a1 and 20b1. Has been.

  The first and second diaphragm springs 20a3 and 20b3 are formed in an annular shape. The first diaphragm spring 20a3 is disposed on the opposite side of the first pressure plate 20a2 in the axial direction with the center plate 20c1 interposed therebetween. The outer diameter portion of the first diaphragm spring 20a3 and the first pressure plate 20a2 are connected by a cylindrical connecting portion 20a4. The first diaphragm spring 20a3 is supported by the tip of the arm portion 20c2 extending from the center plate 20c1.

  In such a state, the connecting portion 20a4 is biased toward the engine 11 by a spring force that biases the outer diameter portion of the first diaphragm spring 20a3 in the direction of the engine 11, whereby the first pressure plate 20a2 is moved to the first clutch disk. It is separated from 20a1.

  When the inner diameter portion of the first diaphragm spring 20a3 is pressed toward the engine 11, the spring force of the outer diameter portion of the first diaphragm spring 20a3 toward the engine 11 is attenuated. At the same time, the outer diameter portion of the first diaphragm spring 20a3 is moved in the direction opposite to the engine 11 with the tip of the arm portion 20c2 extending from the center plate 20c1 as a fulcrum. As a result, the first pressure plate 20a2 moves in the direction of the first clutch disk 20a1, and eventually the first clutch disk 20a1 is sandwiched and pressed against the center plate 20c1. Then, it is completely engaged and the rotational driving force of the engine 11 is transmitted to the first input shaft 31a.

  The second diaphragm spring 20b3 is disposed on the engine 11 side of the arm portion 20c2 of the center plate 20c1, and is disposed on the opposite side of the second clutch disk 20b1 in the axial direction with the second pressure plate 20b2 interposed therebetween. The outer diameter portion of the second diaphragm spring 20b3 is arranged so that the spring force urges the arm portion 20c2 of the center plate 20c1 in the direction opposite to the engine 11 side. As a result, the second pressure plate 20b2 is not pressure-bonded to the second clutch disk 20b1 during normal operation.

  When the inner diameter portion of the second diaphragm spring 20b3 is pressed toward the engine 11, the vicinity of the pressing portion moves in the direction of the engine 11 with the outer diameter portion of the second diaphragm spring 20b3 contacting the arm portion 20c2 as a fulcrum. As a result, the second pressure plate 20b2 is pushed by the diaphragm spring 20b3 and moves in the direction of the second clutch disk 20b1, and eventually the second clutch disk 20b1 is sandwiched and pressed against the center plate 20c1. Then, it is completely engaged and the rotational driving force of the engine 11 is transmitted to the second input shaft 31b.

  The pressing of the inner diameter portion of the first diaphragm spring 20a3 and the inner diameter portion of the second diaphragm spring 20b3 is performed by the first and second clutch actuators 25a and 25b. The first and second clutch actuators 25a and 25b are linearly moved by the ball screw mechanism by the operation of the DC electric motors 25a1 and 25b1, and the DC electric motors 25a1 and 25b1, respectively. Rods 25a2 and 25b2 that transmit to the inner diameter part, and stroke sensors 26a and 26b that detect the stroke amount of linear motion of the rods 25a2 and 25b2 are provided.

  Information relating to the stroke amount of the linear motion of the rods 25a2 and 25b2 detected by the stroke sensors 26a and 26b (information relating to the engagement amount) is sent to the transmission control unit 23a of the TCU 23 as shown in FIG.

  The clutch disks 20a1 and 20b1 of the first and second clutches 20a and 20b are frictionally engaged between the center plate 20c1 and the pressure plates 20a2 and 20b2 by an engagement force corresponding to the stroke amount of the clutch actuators 25a and 25b. It has come to be. Thereby, the clutch torque according to the stroke amount of the clutch actuators 25a and 25b is obtained.

  FIG. 4 is a time chart schematically showing the operation of the dual clutch automatic transmission 10 at the time of shifting.

  Normally, in the automatic transmission 10, one clutch 20a or 20b of the dual clutch 20 is engaged, and the power of the engine 11 is transmitted to the drive wheels 16a and 16b via a predetermined gear stage of the transmission 17. . For example, the first clutch 20a is now engaged, and the sleeve of the first gear shift clutch 71 is slid leftward in FIG. 2 so that the third speed driven gear 63 cannot rotate relative to the first countershaft 35. It is assumed that the vehicle is traveling at a third speed. On the other hand, it is assumed that the engagement of the first clutch 20a is released.

  In this state, it is assumed that, for example, a shift up command is sent from the transmission control unit 23a of the TCU 23 to the transmission 17 and the dual clutch 20. Thereby, at time t1 in FIG. 4, switching of the first and second clutches 20a and 20b is started.

  That is, at time t1, disengagement of the first clutch 20a that has transmitted the driving force of the engine 11 to the first input shaft 31a in the fully engaged state is started, and at time t3, the first clutch 20a is released. The engagement is completely released. On the other hand, at time t2 slightly later than time t1, engagement of the second clutch 20b in the disconnected state is started, and at time t3, the second clutch 20b is controlled to the half-clutch state (clutch torque Tc1). Thereafter, the half-clutch state is maintained until time t4.

  Until the time t2 when the engagement of the second clutch 20b is started, the drive shaft 12 of the engine 11 rotates at the same rotation speed Ne as the rotation speed N1 of the first input shaft 31a. Further, since the rotation is transmitted to the second input shaft 31b from the drive wheels 16a and 16b in the state where the engagement of the second clutch 20b is released, the second input shaft 31b is connected to the first input shaft 31b. Rotating at a lower rotational speed N2 than the shaft 31a. Then, from time t2 to time t4, the rotational speed Ne of the drive shaft 12 of the engine 11 gradually decreases and synchronizes with the rotational speed N2 of the second input shaft 31b. When the rotational speed Ne of the drive shaft 12 of the engine 11 is synchronized with the rotational speed N2 of the second input shaft 31b, the engagement torque of the second clutch 20b is increased to the target clutch torque, and a complete engagement state is established.

  In this way, during the shift control, the second clutch 20b is controlled to the half-clutch state, so that the behavior of the vehicle can be stabilized and a good feeling can be ensured. On the other hand, the second clutch 20b slips due to the half-clutch control, that is, the clutch disk 20b1 of the second clutch 20b slips with respect to the clutch housing 20c. As a result, the clutch temperature of the dual clutch 20 increases, and the clutch temperature is estimated by the clutch temperature estimation unit 23b.

  Next, a control program by the TCU 23 based on the clutch temperature of the dual clutch 20 will be described based on the flowchart of FIG. In the flowchart of FIG. 5, for example, an example in which an up-shift is performed from the third speed to the fourth speed in a state where the vehicle is traveling at the third speed shift stage will be described.

  First, in step S100, the clutch temperature T0 is calculated by the clutch temperature estimation unit 23b of the TCU 23. Next, in step S102, it is determined whether or not the calculated estimated clutch temperature T0 is higher than a predetermined set temperature (threshold) T1. If the estimated clutch temperature T0 is lower than the threshold value T1, the determination result is N, the process proceeds to step S104, the non-traveling gear stage gear is selected according to the traveling state of the vehicle, and the process waits.

  Then, when the accelerator travel is increased or the like so that the traveling state of the vehicle is suitable for the fourth speed traveling, the shift control unit 23a of the TCU 23 sends a gear shift command to the fourth speed (step S106). Based on the shift command, in step S108, the sleeve of the second gear shift clutch 72 is slid rightward in FIG. 2, and the 4-speed driven gear 64 is connected to the first countershaft 35 so as not to be relatively rotatable. Shift change to stage.

  On the other hand, if the determination result in step S102 is Y (when the estimated clutch temperature T0 is higher than the threshold value T1), the process proceeds to step S110, where the shift gear ( Switch to the gear stage (second gear) that is one gear lower than the third gear).

  That is, the shift control unit 23a slides the sleeve of the fourth gear shift clutch 74 leftward in FIG. 2, and the second speed driven gear 62 is connected to the second countershaft 36 so as not to be relatively rotatable. As a result, from the drive wheels 16a and 16b side of the vehicle traveling at the third speed gear stage, via the second countershaft 36, the second speed driven gear 62, the second speed drive gear 52 and the second input shaft 31b, The clutch disk 20a1 (see FIG. 3) of the second clutch 20b in the disconnected state rotates (idles) in the clutch housing 20c.

  At this time, since the gear stage on the lower speed side than the currently operating gear stage gear is connected to the second clutch 20b in the disconnected state, it is connected to the non-travel side gear stage gear. The clutch disk 20b1 of the second clutch 20b can idle in the clutch housing 20c at a higher rotational speed than the clutch disk 20a1 of the first clutch 20a connected to the shift gear on the traveling side.

  Thereby, since the motion of the air in the clutch housing 20c is accelerated by the idling clutch disc 20a1, the dual clutch 20 is cooled, and the temperature rise of the dual clutch 20 can be suppressed. In particular, since the rotational speed of the clutch disk 20a1 adjacent to the center plate 20c1 of the clutch housing 20c is increased, the center plate 20c1 that is most likely to rise in temperature can be effectively cooled.

  In such a state, when the accelerator travel is increased and the vehicle traveling state is suitable for the fourth speed traveling, a gear shift command to the fourth speed is transmitted in step S112. As a result, in the subsequent step S114, the cooling operation of the dual clutch 20 is interrupted, and the gear shift gear (fourth gear) according to the traveling state is changed.

  The above-described step S102 constitutes a clutch temperature determination unit that determines whether or not the clutch temperature estimated by the clutch temperature estimation unit 23b is higher than a preset set temperature (threshold value) T1, When it is determined in step S110 that the clutch temperature is equal to or higher than the set temperature, the non-traveling gear switching unit is configured to switch the non-traveling side gear to the low speed side and increase the rotational speed of the disconnected clutch. Is configured.

  Thus, when the estimated clutch temperature T0 of the dual clutch 20 exceeds the threshold value T1, the disengaged clutch (first clutch 20a) is idled at a gear position that is one gear lower than the currently geared gear. As a result, the clutch disk 20a1 that idles in the clutch housing 20c accelerates the flow of air in the clutch housing 20c, and suppresses an increase in the temperature of the dual clutch 20 as shown in FIG.

  According to the above-described embodiment, when the clutch temperature determination unit (S102) determines that the clutch temperature T0 is equal to or higher than the set temperature, the odd-numbered gear or the even-numbered gear on the non-travel side is set to the low-speed side. Since the rotational speed of the clutch in the disconnected state is increased, the clutch disk 20a1 of the clutch connected to the non-traveling gear stage gear is connected to the traveling gear stage gear in the clutch housing 20c. The clutch can be idled at a higher rotational speed than the clutch disk 20a1 of the clutch. As a result, the movement of the air in the clutch housing 20c is accelerated by the clutch disk 20a1 of the idling clutch, so that the dual clutch 20 is cooled and the temperature rise of the dual clutch 20 can be suppressed. The dual clutch 20 is not necessarily limited to a dry clutch.

  In the above-described embodiment, the automatic transmission 10 has been described by taking a dual clutch automatic transmission (DCT) as an example. However, the automatic transmission 10 is not limited to a dual clutch automatic transmission. It can also be applied to a controlled manual transmission (AMT). Moreover, it can also be applied to a transmission in which only the clutch operation of a conventional manual transmission is automated.

  In the above-described embodiment, the automatic transmission 10 applied to the FF type vehicle has been described as an example. However, the automatic transmission 10 is installed in an FR type (front engine / rear drive) type vehicle. You can also.

  Furthermore, in the above-described embodiment, the automatic transmission 10 including the clutch temperature estimation unit 23b that estimates the clutch temperature from the heat generation amount and the heat dissipation amount of the clutch 20 has been described. However, the clutch temperature uses a temperature sensor. The clutch temperature detecting unit may directly detect the temperature of the clutch 20, and the clutch temperature deriving unit in the claims includes those estimated by the clutch temperature estimating unit 23b and those detected by the clutch temperature detecting unit. Is included.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present invention described in the claims. Of course there is.

  The dual clutch type automatic transmission according to the present invention is suitable for use with a dual clutch comprising a first clutch and a second clutch coupled to first and second input shafts and enabling pre-shifting.

  DESCRIPTION OF SYMBOLS 10 ... Dual clutch type automatic transmission, 11 ... Motor | power_engine (engine), 17 ... Transmission apparatus, 20 ... Dual clutch, 21 ... 1st clutch, 22 ... 2nd clutch, 23a ... Shift control part, 23b ... Clutch temperature derivation part (Clutch temperature estimation part), 31 ... first input shaft, 32 ... second output shaft, 51, 53, 55, 57 ... odd gear drive gear, 52, 54 ... even gear drive gear, 61, 63, 65 , 67... Odd-numbered gear driven gears, 62, 64, 66... Even-numbered gear driven gears, 71, 73, first shift mechanism, 72, 74, second shift mechanism, S 102, S 110, non-travel side gear switching unit.

Claims (3)

A first input shaft and a second input shaft arranged concentrically;
A dual clutch having a first clutch for transmitting the rotational driving force of the prime mover to the first input shaft and a second clutch for transmitting the rotational driving force to the second input shaft;
A first shift mechanism that shifts the rotational driving force transmitted to the first input shaft to establish an odd-numbered shift stage and a shift mechanism that shifts the rotational driving force transmitted to the second input shaft to establish an even-numbered shift stage. A transmission having a second shift mechanism
A clutch temperature deriving unit for deriving the temperature of the dual clutch;
A clutch temperature determining unit that determines whether or not the clutch temperature derived by the clutch temperature deriving unit is higher than a preset set temperature;
When the clutch temperature determining unit determines that the clutch temperature is equal to or higher than the set temperature, the gear of the odd speed stage on the non-travel side or the gear of the even speed stage is switched to the low speed side to rotate the clutch in the disconnected state. A non-traveling gear switching unit that controls to increase the speed;
Dual-clutch automatic transmission with   The clutch temperature estimated according to claim 1, wherein the clutch temperature deriving unit subtracts the heat release temperature calculated based on the ambient temperature outside the dual clutch from the heat generation temperature calculated based on the work of the dual clutch. A dual clutch automatic transmission configured by an estimation unit.   3. The dual clutch automatic transmission according to claim 1 or 2, wherein the dual clutch is a dry clutch.

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