JPWO2018083988A1 - Control device of automatic transmission and control method of automatic transmission - Google Patents

Abstract

When upshifting the automatic transmission during coasting, the control device slips the friction clutch to reduce the rotational speed of the engine to the target engine rotational speed and then executes the upshift.

Description

  The present invention relates to a control device of an automatic transmission and a control method of the automatic transmission.

  JP 2009-298199 A discloses that, when upshifting the continuously variable transmission, the engine torque is reduced to offset the inertia torque generated as the engine rotation speed decreases. According to this, the shift shock accompanying the upshift is suppressed.

  Further, JP2009-298199A discloses that when the engine torque can not be reduced, the occurrence of inertia torque is suppressed by reducing the shift speed.

  However, in the technology disclosed in JP2009-298199A, a vehicle equipped with an automatic transmission such as a general stepped automatic transmission or a seamless automatic transmission (see, for example, JP2012-127471A) which has difficulty in finely controlling the transmission speed. In the case where the coast-up driving is being performed and the engine torque can not be reduced, there is a problem that the occurrence of the inertia torque can not be suppressed.

  An object of the present invention is to suppress the occurrence of engine inertia torque when upshifting during coasting.

  According to an aspect of the present invention, there is provided a control device of an automatic transmission including a transmission mechanism, and a friction clutch provided between an engine and the transmission mechanism, the automatic transmission being up during coasting. When shifting, the control device for an automatic transmission is provided, in which the friction clutch is slipped to reduce the rotational speed of the engine to a target engine rotational speed and then the upshift is performed.

  Further, according to another aspect of the present invention, there is provided a control method of an automatic transmission including a transmission mechanism and a friction clutch provided between an engine and the transmission mechanism, the automatic transmission being performed during coasting. When upshifting the machine, the control method of the automatic transmission is provided, in which the friction clutch is slipped to reduce the rotational speed of the engine to a target engine rotational speed and then the upshift is performed.

  In these aspects, during coasting, the rotational speed of the engine is reduced before upshifting, so it is possible to suppress the occurrence of engine inertia when the upshift is performed. Thus, the shift shock can be suppressed.

FIG. 1 is a schematic configuration view of a vehicle according to an embodiment of the present invention. FIG. 2 is a schematic block diagram of an automatic transmission. FIG. 3 is a view showing a plurality of cam grooves. FIG. 4 is a flowchart showing the contents of control performed by the ATCU. FIG. 5 is a time chart for explaining how an upshift is performed during coasting.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

  FIG. 1 is a schematic block diagram of a vehicle 100. As shown in FIG. The vehicle 100 includes an engine 50. The power of the engine 50 is transmitted to the drive wheels 52 via the automatic transmission 1 and the differential device 51.

  The ATCU 10 is an automatic transmission control unit as a control device that controls the automatic transmission 1. The ATCU 10 receives signals from an accelerator opening sensor 11 that detects an accelerator opening APO that is an operation amount of an accelerator pedal, a vehicle speed sensor 12 that detects a vehicle speed VSP, and the like. The ATCU 10 is communicably connected to the ECU 20.

  The ECU 20 is an engine control unit that controls the engine 50. The ECU 20 outputs the rotational speed (engine rotational speed) Ne of the engine 50, the throttle opening degree TVO, and the like to the ATCU 10.

  Note that, instead of separately providing the ATCU 10 and the ECU 20, an integrated control unit in which the functions of both are integrated may be provided. Further, the functions of the ATCU 10 may be shared by the ECU 20 and other control units. The same applies to the ECU 20.

  Each control unit can be configured by a microcomputer provided with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM) and an input / output interface (I / O interface). It is also possible to configure each control unit with a plurality of microcomputers.

  FIG. 2 is a schematic block diagram of the automatic transmission 1. In FIG. 2, the shift drum 21 and the check mechanism 3 described below are shown in a developed state. The automatic transmission 1 includes a friction clutch CL provided between the transmission mechanism 2, the check mechanism 3, the drive motor 4, and the engine 50, and a hydraulic circuit (not shown) for supplying the hydraulic pressure Pc to the friction clutch CL. And. The automatic transmission 1 has a plurality of shift speeds including first, second and third shift speeds.

  The transmission mechanism 2 includes a shift drum 21, a rod mechanism 22, and a transmission gear portion 23. The shift drum 21 has a plurality of cam grooves 211.

  The plurality of cam grooves 211 have a cam shape corresponding to the shift pattern. Specifically, the shift pattern is a sequential shift pattern in which the shift speeds are sequentially achieved in one operation direction. The shift drum 21 has a plurality of cam grooves 211, and is a switching element in which a shift pattern is set.

  The shift drum 21 has a plurality of switching positions according to each gear and neutral. Specifically, the plurality of switching positions are, in order, the first gear position GP1, the neutral position NP, the second gear position GP2, the neutral position NP, and the third gear position GP3.

  The neutral position NP is set adjacent to the shift lower position LP and the shift upper position UP at the time of upshift. For example, in the upshift from the first gear to the second gear, the first gear position GP1 is the shift lower position LP, and the second gear position GP2 is the shift upper position UP.

  The rod mechanism 22 has a plurality of shift rods 221, a plurality of shift arms 222, and a plurality of shift forks 223. The specific shapes of the plurality of shift rods 221 may be different from one another. The same applies to the plurality of shift arms 222, the plurality of shift forks 223, and the plurality of lock prevention mechanisms 236 described later.

  The shift rod 221 is provided for each cam groove 211. Each shift rod 221 is provided with a shift arm 222 and a shift fork 223. The shift arm 222 engages with the cam groove 211, and the shift fork 223 engages with a sleeve 235 described later.

  The transmission gear unit 23 includes a main shaft 231, a counter shaft 232, a plurality of gears 233, a plurality of hubs 234, a plurality of sleeves 235, and a plurality of lock prevention mechanisms 236. The plurality of gears 233 includes a first gear 233a, a second gear 233b, and a third gear 233c. The plurality of hubs 234 include a first speed hub 234a, a second speed hub 234b, and a third speed hub 234c, and the plurality of sleeves 235 include a first speed sleeve 235a and a second speed sleeve 235b and 235c.

  The power from the engine 50 is input to the main shaft 231 via the friction clutch CL. The counter shaft 232 is provided in parallel with the main shaft 231, and has a plurality of counter shaft gear portions that mesh with the plurality of gears 233. Power is transmitted to the counter shaft 232 from the main shaft 231 via the gears of the gear stages in the achieved state among the plurality of gears 233.

  Each of the plurality of gears 233 is provided on the main shaft 231 so as to be relatively rotatable. Each of the plurality of gears 233 includes a first dog clutch portion having a plurality of dog teeth made of external teeth. The first dog clutch portion constitutes a clutch element on the side where the meshing operation is not performed.

  Each of the plurality of hubs 234 is provided on the main shaft 231 and rotates with the main shaft 231. The hub 234 may be a part of the main shaft 231 or may be fixed to the main shaft 231 as a separate member from the main shaft 231.

  A sleeve 235 is provided on the outer periphery of each of the plurality of hubs 234. The sleeve 235 is provided movably in the axial direction of the main shaft 231 while rotating with the corresponding hub 234. The mutually corresponding hub 234 and sleeve 235 may, for example, be splined. A shift fork 223 engages with the outer circumference of each of the plurality of sleeves 235 while allowing the sleeves 235 to rotate. Each of the plurality of sleeves 235 is moved in the axial direction of the main shaft 231 by the shift fork 223.

  Each of the plurality of sleeves 235 includes a second dog clutch portion. The second dog clutch portion is a clutch element on the side to be meshed, moves in the axial direction of the main shaft 231, and meshes with the corresponding first dog clutch portion to release the meshing. The second dog clutch portion constitutes a dog clutch DG together with the corresponding first dog clutch portion.

  The automatic transmission 1 has a plurality of dog clutches DG. The plurality of dog clutches DG include a first gear dog clutch DG1, a second gear dog clutch DG2 and a second gear dog clutch DG3 for achieving first gear, second gear and third gear. When any one of the plurality of dog clutches DG is engaged, the corresponding gear 233 rotates with the main shaft 231, and the shift gear is achieved. In FIG. 2, the first gear dog clutch DG1 is in meshing state, and the second and third gear dog clutches DG2 and DG3 are in the release state, and the first gear is achieved.

  The lock prevention mechanism 236 is provided to the hub 234 and the sleeve 235 of the shift speeds that constitute the shift lower stage at least during the upshift among the shift speeds. The lock prevention mechanism 236 will be described later.

  The check mechanism 3 holds the transmission mechanism 2 at the switching position. Specifically, the check mechanism 3 is provided on the shift drum 21 and holds the shift drum 21 at the switching position. Thus, the entire transmission mechanism 2 is also held at the switching position. The check mechanism 3 includes a check ball 31, a plurality of check grooves 32, and a spring 33.

  The check ball 31 holds the shift drum 21 in a state of being engaged with any of the plurality of check grooves 32. Specifically, the check ball 31 is provided to hold the check groove 32 corresponding to the current switching position. In FIG. 2, since the current switching position of the shift drum 21 is the first speed position GP1, the check ball 31 holds the check groove 32 corresponding to the first speed position GP1.

  The plurality of check grooves 32 are provided along the operating direction of the shift drum 21. The check groove 32 is provided corresponding to each switching position. Specifically, the check groove 32 is provided at the same position as each switching position in the rotation direction of the shift drum 21.

  The plurality of check grooves 32 are configured to have a check groove 321 which is a first check groove and a check groove 322 which is a second check groove. The check groove 321 is the check groove 32 corresponding to the first gear position GP1 to the third gear position GP3, that is, the check groove 32 corresponding to each gear. The check groove 322 is a check groove 32 corresponding to the neutral position NP. The spring 33 constitutes a biasing member that biases the check ball 31.

  The drive motor 4 constitutes a drive source that drives the transmission mechanism 2 so as to change the switching position. Specifically, the drive motor 4 drives the transmission drum 2 in this manner by driving the shift drum 21. The drive motor 4 is controlled by the ATCU 10.

  Further, the ATCU 10 outputs a control command value to the hydraulic circuit, and adjusts the hydraulic pressure Pc supplied from the hydraulic circuit to the friction clutch CL. Thereby, the engagement state of the friction clutch CL is controlled.

  In addition to the signals from the accelerator opening sensor 11 and the vehicle speed sensor 12 described above being input to the ATCU 10, as shown in FIG. 1, a shift switch 13 for detecting a shift operation on a sequential shift lever, a shift drum A signal from a position sensor 14 that detects the position of 21 is input. Specifically, the position sensor 14 detects a shift drum rotational angle that represents the rotational position of the shift drum 21.

  The ATCU 10 rotates the shift drum 21 in the shift-up drive direction SUD shown in FIG. 2 when the up-shift operation is performed, and performs the shift drum 21 in the shift-down drive direction SDD when the downshift operation is performed. Rotate.

  FIG. 3 is a view showing a plurality of cam grooves 211. As shown in FIG. In the following, the upshift from 1st gear to 2nd gear is mainly described as an example, but the upshift from 2nd gear to 3rd gear is also similar to the upshift from 1st gear to 2nd gear.

  Specifically, as shown in FIG. 3, the plurality of cam grooves 211 are a first speed cam groove 211a, a second speed cam groove 211b, and a third speed cam groove for achieving the first, second and third speeds. And 211c. Further, each of the plurality of cam grooves 211 has a meshing groove D1 for positioning the corresponding sleeve 235 at the meshing position, a meshing release groove D2 for positioning the corresponding sleeve 235 at the meshing release position, a meshing groove D1 and a meshing release groove D2 And a transition groove D3 connecting the two.

  In the second speed cam groove 211b, a transition groove D3 is provided from the neutral position NP to an intermediate position between the neutral position NP and the second speed position GP2. A free groove D31 is provided in the first speed cam groove 211a so that the setting range in the rotation direction of the shift drum 21 overlaps with the transition groove D3.

  The free groove D31 is a shift upper position UP side groove wall portion so that the setting range in the rotation direction of the shift drum 21 does not overlap between the shift upper position UP side groove wall portion of the transition groove D3 and the shift lower position LP side groove wall portion. Is provided on the shift upper position UP side. The free groove D31 has a shape in which the meshing groove D1 and the meshing release groove D2 are integrally connected in the width direction of the cam groove 211. In the free groove D31, the position of the shift arm 222 is not restricted by the cam groove 211 between the position corresponding to the meshing groove D1 and the position corresponding to the meshing release groove D2.

  Therefore, even if the switching position of the shift drum 21 changes from the first speed position GP1 to the neutral position NP, in the first speed cam groove 211a, the shift arm 222 located in the meshing groove D1 is a position equivalent to the meshing release groove D2. , And remains at the position equivalent to the meshing groove D1, and the upshift is continued.

  The meshing of the second speed dog clutch DG2 is started when the shift arm 222 passes the transition groove D3 in the second speed cam groove 211b. As a result, both the first speed dog clutch DG1 and the second speed dog clutch DG2 are engaged. That is, simultaneous meshing of the first speed dog clutch DG1 and the second speed dog clutch DG2 occurs.

  When simultaneous meshing occurs, torque acts on the first speed sleeve 235a through the second speed gear 233b, the countershaft 232, and the first speed gear 233a from the second speed sleeve 235b according to the engagement of the second speed dog clutch DG2. As a result, the first speed sleeve 235 a is accelerated with respect to the main shaft 231.

  At this time, the lock prevention mechanism 236 at the lower shift stage provided for the first speed generates an axial force in the mesh release direction on the first speed sleeve 235a while permitting relative rotation with respect to the second speed sleeve 235b.

  That is, the lock prevention mechanism 236 allows relative rotation between the upper gearshift sleeve 235 and the lower gearshift sleeve 235 when the upper gearshift sleeve and the lower gear sleeve 235 simultaneously mesh during upshifting.

  Further, the lock prevention mechanism 236 is a torque acting on the dog clutch DG in the lower shift stage according to the meshing of the dog clutch DG in the upper shift stage while allowing such relative rotation. Produces an axial force. Specifically, here, the axial force acts on the second dog clutch portion of the first speed sleeve 235a. On the other hand, in the first speed cam groove 211a, the shift arm 222 is located in the free groove D31.

  Therefore, combined with the fact that the shift arm 222 can be moved to the position equivalent to the meshing release groove D2 by the first speed cam groove 211a, the first speed sleeve 235a is moved to the meshing release position by the axial force, thereby the first speed dog clutch DG1. Meshing is released.

  The lock prevention mechanism 236, together with the shift drum 21 and the rod mechanism 22, constitutes a meshing release mechanism RM. During upshifting, the meshing release mechanism RM simultaneously engages the dog clutch DG of the lower shift stage corresponding to the lower shift stage during the upshift among the plurality of dog clutches DG and the dog clutch DG of the upper shift stage corresponding to the upper shift stage. Further, the meshing release mechanism RM releases the meshing of the lower gear shift dog clutch DG by the torque acting on the lower gear shift dog clutch DG according to the meshing of the upper gear shift dog clutch DG.

  The automatic transmission 1 is configured as a seamless automatic transmission by including the meshing release mechanism RM. In the seamless automatic transmission, the simultaneous meshing is performed as described above to perform the upshift, so that the power from the engine 50 to the drive wheels 52 can be prevented from being interrupted by the upshift. The meshing release mechanism RM can also be grasped that the transmission gear portion 23 including the lock prevention mechanism 236 is configured together with the shift drum 21 and the rod mechanism 22.

  The downshift is as follows. That is, at the time of the downshift, the friction clutch CL is released once. Then, at the neutral position NP, the automatic transmission 1 is brought into the neutral state without performing simultaneous meshing, and in this state, synchronous control of the dog clutch DG on the lower shift side is performed. In the synchronous control, the friction clutch CL is connected, and the engine 50 synchronizes the rotation of the dog clutch DG. Then, when the synchronous control is completed, the friction clutch CL is released to engage the dog clutch DG.

  By the way, the shift position of the automatic transmission 1 is determined based on a map using the accelerator opening APO and the vehicle speed VSP as parameters. Therefore, in the vehicle 100, an upshift may be performed, for example, when coasting on a downhill road.

  Here, when upshifting, it is considered that the torque (engine torque) Te of the engine 50 is reduced to offset the inertia torque Tiner generated along with the change of the engine rotational speed Ne and to suppress the shift shock. Be Further, when the engine torque Te can not be reduced, it is conceivable to suppress the occurrence of the inertia torque by reducing the shift speed.

  However, in the automatic transmission 1 of the present embodiment, it is difficult to finely control the shift speed, as can be understood from the above-described configuration. Therefore, if the engine torque Te can not be reduced during coasting, the occurrence of the inertia torque can not be suppressed, and as a result, a shift shock may occur.

  For this reason, the ATCU 10 according to the present embodiment is configured to be able to suppress the occurrence of the inertia torque at the time of upshifting during coasting by executing the control shown in the flowchart of FIG. 4 while traveling.

  Hereinafter, the contents of control executed by the ATCU 10 will be described in detail with reference to FIG.

  In step S11, the ATCU 10 determines whether the vehicle 100 is coasting. Specifically, ATCU 10 determines that vehicle 100 is coasting when vehicle 100 is coasting with accelerator opening APO = 0.

  If ATCU 10 determines that vehicle 100 is traveling on a coast, it shifts the process to step S12. If it is determined that the vehicle 100 is not coasting, the process of step S11 is repeated.

  In step S12, it is determined whether the upshift condition is satisfied. As described above, the determination in step S12 is performed based on the map using the accelerator opening APO and the vehicle speed VSP as parameters.

  If ATCU 10 determines that the upshift condition is satisfied, it shifts the process to step S13. If it is determined that the upshift condition is not satisfied, the process returns to step S11 to repeat the process.

  In step S13, the ATCU 10 determines whether the engine torque Te is larger than a predetermined lower limit torque.

  The predetermined lower limit torque is a lower limit value of the torque that can cancel the inertia torque Tiner generated along with the change of the engine rotation speed Ne by decreasing the engine torque Te when upshifting. That is, when the engine torque Te is larger than the lower limit torque, there is a reduction allowance of the engine torque Te which can cancel the inertia torque Tiner. On the other hand, when the engine torque Te is equal to or less than the lower limit torque, since the reduction amount of the engine torque Te is small, it is impossible to cancel the inner torque as it is aimed at.

  If ATCU 10 determines that engine torque Te is larger than the lower limit torque, it shifts the process to step S14. If it is determined that the engine torque Te is equal to or less than the lower limit torque, the process proceeds to step S15. When stopping fuel injection during coasting, the engine torque Te is equal to or less than the lower limit torque.

  In step S14, the ATCU 10 reduces the engine torque Te to execute the upshift.

  In step S15, the ATCU 10 causes the friction clutch CL to slip. Specifically, the control command value is output to the hydraulic circuit, and the hydraulic pressure Pc supplied from the hydraulic circuit to the friction clutch CL is reduced.

  The control command value is set such that the torque capacity of the friction clutch CL is slightly lower than the engine torque Te. As a result, the friction clutch CL slips, and the engine rotation speed Ne decreases.

  In step S16, the ATCU 10 calculates a target engine rotational speed TNe. The target engine rotational speed TNe is obtained by multiplying the rotational speed of the countershaft 232 which is the output shaft of the automatic transmission 1 by the through transmission ratio of the automatic transmission 1 after the upshift.

  In step S17, the ATCU 10 determines whether the engine rotational speed Ne has become equal to or lower than the target engine rotational speed TNe.

  If ATCU 10 determines that engine rotational speed Ne has become equal to or lower than target engine rotational speed TNe, it shifts the process to step S18. If it is determined that the engine rotational speed Ne is higher than the target engine rotational speed TNe, the process of step S17 is repeated.

  In step S18, the ATCU 10 performs an upshift.

  In step S19, the ATCU 10 brings the friction clutch CL into engagement. Specifically, the control command value is output to the hydraulic circuit, and the hydraulic pressure Pc supplied from the hydraulic circuit to the friction clutch CL is raised to the engagement pressure.

  As described above, the ATCU 10 of the present embodiment reduces the engine rotation speed Ne to the target engine rotation speed TNe when it is not possible to offset the inertia torque Tiner by reducing the engine torque Te when upshifting during coasting. After doing this, execute the upshift.

  According to this, it is possible to suppress the generation of the inertia torque Tiner when the upshift is performed. Therefore, it is possible to suppress shift shock during upshifting. Further, in the present embodiment, since the friction clutch CL is in the slip state even during the upshift, the occurrence of the shift shock is further suppressed.

  Next, with reference to the time chart of FIG. 5, the manner in which the upshift is performed after the engine rotational speed Ne is reduced during coasting will be described. In FIG. 5, since the vehicle 100 is coasting, the driving force of the vehicle 100, the engine torque Te, and the input torque Tinp to the automatic transmission 1 are negative (engine brake state).

  When the upshift condition is satisfied at time t1, the oil pressure Pc supplied from the hydraulic circuit to the friction clutch CL decreases, and the friction clutch CL is slipped. As a result, the engine rotation speed Ne gradually decreases.

  Although an inertia torque Tiner is generated with the change of the engine rotation speed Ne, a large inertia torque Tiner is not generated because the friction clutch CL is slipped to gradually reduce the engine rotation speed Ne.

  From time t1 to time t2, the engine speed Ne decreases to the target engine speed TNe.

  Between time t1 and time t2, since the friction clutch CL is in a slip state, the inertia torque Tiner is hardly transmitted to the automatic transmission 1. Therefore, the input torque Tinp and the driving force do not change.

  When the engine speed Ne decreases to the target engine speed TNe at time t2, the upshift is performed. At this time, since the hydraulic pressure Pc supplied from the hydraulic circuit to the friction clutch CL is slightly raised to return the capacity of the friction clutch CL, the engine rotation speed Ne does not continue to decrease even after time t2. As a result, from time t2 to time t3, the rotational speed Ninp of the main shaft 231, which is the input shaft of the automatic transmission 1, decreases to a speed that matches the engine rotational speed Ne.

  From time t2 to time t3 during upshift execution, the driving force of the vehicle 100 fluctuates to the positive side (forward side) due to the influence of the inertia torque inside the automatic transmission 1. However, since the inertia itself inside the automatic transmission 1 is very small compared to the engine 50, the fluctuation of the driving force, that is, the shift shock, is large compared to the case where the upshift is performed without reducing the engine rotation speed Ne. Suppressed.

  As described above, according to the present embodiment, when upshifting the automatic transmission 1 during coasting, the ATCU 10 causes the friction clutch CL to slip and the engine rotational speed Ne to the target engine rotational speed TNe. Execute upshift after lowering.

  According to this, during coasting, since the engine rotation speed Ne is decreased before upshifting, generation of inertia torque Tiner of the engine 50 when upshifting is performed can be suppressed. Thus, the shift shock can be suppressed.

  Further, the automatic transmission 1 includes a plurality of dog clutches DG for achieving the shift speed, a dog clutch DG for the lower shift stage corresponding to the lower shift stage during the upshift among the plurality of dog clutches DG during the upshift, A meshing release mechanism for simultaneously meshing the corresponding dog clutch DG in the upper stage of the gear shift and releasing the meshing of the dog clutch DG in the lower gear stage with a torque acting on the dog clutch DG in the lower gear stage according to the meshing of the dog clutch DG in the upper stage It is a seamless automatic transmission equipped with an RM.

  In such a seamless automatic transmission, since upshifting is completed in a short time, a large inertia torque Tiner tends to occur. On the other hand, in the control executed by the ATCU 10, the engine rotational speed Ne is decreased before upshifting, so even when the automatic transmission 1 is a seamless automatic transmission, the engine 50 when upshifting is performed It is possible to suppress the occurrence of the inertia torque Tiner.

  As mentioned above, although embodiment of this invention was described, the said embodiment is only what showed one of the application examples of this invention, and the meaning which limits the technical scope of this invention to the specific structure of the said embodiment is not.

  For example, in the above embodiment, the case where the automatic transmission 1 is a seamless automatic transmission has been described. However, the automatic transmission 1 is a general stepped automatic transmission, a sequential automatic transmission that performs gear shifting by driving a gear shift mechanism that achieves a shift speed with a dog clutch and has a sequential shift pattern set by an actuator, etc. It may be. The present invention is also applicable to a continuously variable transmission or the like capable of controlling the shift speed.

  The present application claims priority based on Japanese Patent Application No. 2016-217448 filed on Nov. 7, 2016 in the Japanese Patent Office, and the entire contents of this application are incorporated herein by reference.

Claims (3)

A control device for an automatic transmission, comprising: a transmission mechanism; and a friction clutch provided between an engine and the transmission mechanism,
When upshifting the automatic transmission during coasting, the friction clutch is slipped to reduce the rotational speed of the engine to a target engine rotational speed, and then the upshift is performed.
Control unit of automatic transmission. The control device for an automatic transmission according to claim 1,
The automatic transmission
Multiple dog clutches to achieve the gear position,
At the time of the upshift, the lower gear stage clutch corresponding to the lower gear position at the upshift among the plurality of dog clutches and the upper gear stage clutch corresponding to the upper gear stage are simultaneously meshed to mesh the upper gear stage clutch And a gear release mechanism for releasing the meshing of the lower gear shift clutch with a torque acting on the lower gear shift clutch according to
Control unit of automatic transmission. A control method of an automatic transmission, comprising: a transmission mechanism; and a friction clutch provided between an engine and the transmission mechanism,
When upshifting the automatic transmission during coasting, the friction clutch is slipped to reduce the rotational speed of the engine to a target engine rotational speed, and then the upshift is performed.
Control method of automatic transmission.

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