JP6950277B2 - Control device for automatic transmission - Google Patents

Description

The present invention relates to a control device for an automatic transmission.

Conventionally, various automatic transmissions that shift gears by re-grabbing a plurality of friction fastening elements have been known. For example, a first clutch (friction engaging element) provided between the engine and the odd gear train and a second clutch (friction engaging element) provided between the engine and the even gear train are provided. A dual clutch transmission (DCT) that transmits the driving force from the engine to the output side via the first clutch or the second clutch is known. In addition, it is equipped with a clutch (friction fastening element) that stops the relative rotation of the elements that make up the planetary gear, and a brake (friction fastening element) that stops the rotation of the element, and the driving force from the engine is transmitted via the planetary gear. An automatic transmission (AT) that transmits to the output side is known.

Re-grabbing a plurality of friction fastening elements in these automatic transmissions, that is, releasing one friction fastening element and fastening the other friction fastening element in parallel with each other generates frictional heat at each friction fastening element. .. Excessive frictional heat generation damages the friction fastening elements. Therefore, some kind of heat measures are required.

Therefore, various inventions for preventing damage to the friction fastening element at the time of re-grasping the friction fastening element have been proposed so far.

For example, Patent Document 1 discloses an invention relating to a shift control method for a DCT vehicle. The method is described as "a shift command confirmation stage for confirming whether or not a shift-up shift command is generated during the start control of the DCT vehicle; A slip determination stage for determining whether the rotation speed difference between the rotation speed of the input shaft to be synchronized and the engine rotation speed is within a predetermined reference rotation speed; When the difference between the number and the engine speed is within the reference speed order, the control conversion step of ending the start control and switching to shift control ”(claim 1) is included.

Japanese Unexamined Patent Publication No. 2014-556666

According to the method described in Patent Document 1, as shown in FIG. 3 of Patent Document 1, the engine torque at the time of re-grabbing is reduced as compared with the engine torque before re-grabbing. Is a different amount for each shift. In addition, no special attention has been paid to the torque actually output from the transmission. Therefore, although damage to the friction fastening element may be prevented, the driver may be given a different acceleration / deceleration feeling for each shift, that is, a sense of discomfort may be given.

The present invention has been made in view of such a situation, and it is possible to prevent a decrease in drivability while preventing excessive heat generation of the friction fastening element when re-grasping the friction fastening element. An object of the present invention is to provide a control device for an automatic transmission capable of performing control.

The automatic transmission control device according to the present invention determines whether or not the shift condition of the transmission for a vehicle that shifts with the re-grasping of a plurality of friction fastening elements and the transition of the engine rotation speed is satisfied. When it is determined by the establishment determination unit and the shift condition establishment determination unit that the shift condition is satisfied, the friction fastening element released prior to the re-grasping of the plurality of friction fastening elements and the transition of the engine rotation speed. A transmission output torque reducing unit that reduces torque capacity and engine torque to reduce the output torque of the transmission by a certain amount is provided , and the plurality of friction fastening elements are a first input side clutch plate and a first output side. It has a first friction engaging element having a clutch plate, a second friction engaging element having a second input side clutch plate and a second output side clutch plate, and the first input side clutch plate and the second input side clutch plate. Is connected so as to rotate integrally with the engine output shaft, the first output side clutch plate is connected so as to rotate integrally with the first input shaft of the transmission, and the second output side clutch plate is said. It is connected so as to rotate integrally with the second input shaft of the transmission, and the engine rotation speed is the first when the first friction fastening element and the second friction fastening element are re-grabbed. The transition from the rotation speed of one of the input shaft and the second input shaft to the rotation speed of the other .

According to the present invention, automatic transmission capable of performing shift control capable of preventing deterioration of drivability while preventing excessive heat generation of the friction fastening element when re-grasping the friction fastening element. A control device for the machine can be provided.

Schematic configuration diagram showing a vehicle to which the control device of the automatic transmission according to the present invention is applied. Functional block diagram of the control device for the automatic transmission according to the present invention. Flow chart showing the flow of control by the control device of the automatic transmission according to the present invention. Time chart when upshifting Time chart when downshifting

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment described below is an example, and the present invention is not limited to this embodiment.

First, the overall configuration of the vehicle will be described with reference to FIG. As shown in FIG. 1, the vehicle 1 includes an engine 10, a DCT2 (automatic transmission) including a first clutch 20, a second clutch 30, a transmission unit 40, and a hydraulic circuit 90, and a control device 50. .. A drive wheel is connected to the output side of the DCT2 via a propeller shaft and a differential gear (not shown) so that power can be transmitted.

The engine 10 is, for example, a diesel engine. The output rotation speed (hereinafter referred to as "engine rotation speed") and output torque of the engine 10 are controlled based on the accelerator opening Acc of the accelerator pedal detected by the accelerator opening sensor 101. Further, the engine output shaft 11 is provided with an engine speed sensor 102 that detects the engine speed.

The first clutch 20 is a hydraulically operated wet multi-plate clutch having a plurality of first input side clutch plates 21 and a plurality of first output side clutch plates 22. The first input side clutch plate 21 rotates integrally with the engine output shaft 11 rotated by the engine 10. The first output side clutch plate 22 rotates integrally with the first input shaft 41 of the transmission unit 40.

The first clutch 20 is urged in the disconnection direction by a return spring (not shown), and the first piston 23 is moved by the clutch operating hydraulic pressure supplied from the hydraulic circuit 90 to move the first input side clutch plate 21 and the first clutch plate 20. 1 The output side clutch plate 22 is brought into contact by pressure contact. When the first clutch 20 is engaged, the power of the engine 10 is transmitted to the first input shaft 41. The engagement and disengagement of the first clutch 20 is controlled by the control device 50. The first clutch 20 may be a dry single plate clutch.

The second clutch 30 is a hydraulically operated wet multi-plate clutch having a plurality of second input side clutch plates 31 and a plurality of second output side clutch plates 32. The second input side clutch plate 31 rotates integrally with the engine output shaft 11. The second output side clutch plate 32 rotates integrally with the second input shaft 42 of the transmission unit 40.

The second clutch 30 is urged in the disconnection direction by a return spring (not shown), and the second piston 33 is moved by the clutch operating hydraulic pressure supplied from the hydraulic circuit 90 to move the second input side clutch plate 31 and the second clutch plate 31. 2 The clutch plate 32 on the output side is brought into contact by pressure contact. When the second clutch 30 is engaged, the power of the engine 10 is transmitted to the second input shaft 42. The engagement and disengagement of the second clutch 30 is controlled by the control device 50. The second clutch 30 may be a dry single plate clutch. Hereinafter, if necessary, the first input side clutch plate 21, the second input side clutch plate 31, the first output side clutch plate 22, and the second output side clutch plate 32 are simply referred to as "clutch plates".

The second clutch 30 is provided on the outer peripheral side of the first clutch 20. Further, the first input shaft 41 is provided with a lubricating oil passage (not shown) including an axial oil passage and one or a plurality of radial oil passages, and lubricating oil is radially injected from the first input shaft 41. By doing so, each clutch plate of the first clutch 20 is cooled, and further, each clutch plate of the second clutch 30 is cooled. The lubricating oil that has cooled each clutch plate of the second clutch 30 flows out from the outer diameter side of the second clutch 30, and returns to an oil pan (not shown) provided in the hydraulic circuit 90. In this embodiment, the case where the second clutch 30 is provided on the outer peripheral side of the first clutch 20 will be described as an example, but the arrangement relationship between the first clutch 20 and the second clutch 30 is based on this. Not limited. Specifically, for example, the second clutch 30 may be arranged on the rear side of the first clutch 20.

The transmission unit 40 includes a first input shaft 41 connected to the output side of the first clutch 20, and a second input shaft 42 connected to the output side of the second clutch 30. Further, the transmission unit 40 includes a sub-shaft 43 arranged in parallel with the first input shaft 41 and the second input shaft 42, and an output shaft 44 arranged coaxially with the first input shaft 41 and the second input shaft 42. And have. Further, a vehicle speed sensor 103 for detecting the vehicle speed V, which is the speed of the vehicle 1, is provided on the rear end side of the output shaft 44.

The speed change unit 40 includes a first speed change unit 60, a second speed change unit 70, and a forward / reverse advance switching unit 80. The first transmission unit 60 includes a first high-speed gear train 61, a first low-speed gear train 62, and a first coupling mechanism 63.

The first high-speed gear train 61 is provided so as to mesh with the first input gear 61a provided so as to be rotatable relative to the first input shaft 41 and to rotate integrally with the sub-shaft 43. It is composed of a first sub gear 61b.

The first low-speed gear train 62 is provided so as to mesh with the second input gear 62a provided so as to be rotatable relative to the first input shaft 41 and the second input gear 62a so as to rotate integrally with the sub-shaft 43. It is composed of a second sub gear 62b.

The first connecting mechanism 63 selectively selects the first input gear 61a and the second input gear 62a by moving the first sleeve 63a in the axial direction (left-right direction in FIG. 1) by a gear shift actuator (not shown). 1 Rotate integrally with the input shaft 41.

The second transmission unit 70 includes a second high-speed gear train 71, a second low-speed gear train 72, and a second coupling mechanism 73. The second high-speed gear train 71 is provided so as to mesh with the third input gear 71a provided so as to be rotatable relative to the second input shaft 42 and the third input gear 71a so as to rotate integrally with the sub-shaft 43. It is composed of a third auxiliary gear 71b.

The second low-speed gear train 72 is provided so as to mesh with the fourth input gear 72a provided so as to be rotatable relative to the second input shaft 42 and the fourth input gear 72a so as to rotate integrally with the sub-shaft 43. It is composed of a fourth auxiliary gear 72b.

The second connecting mechanism 73 selectively rotates the third input gear 71a and the fourth input gear 72a integrally with the second input shaft 42 by moving the second sleeve 73a in the axial direction by a gear shift actuator (not shown). Let me.

The forward / backward switching unit 80 includes a forward gear row 81, a reverse gear row 82, and a third connecting mechanism 83. The forward gear train 81 meshes with the first output gear 81a provided so as to be rotatable relative to the output shaft 44 and the first output gear 81a, and is provided so as to rotate integrally with the auxiliary shaft 43. It consists of a gear 81b.

The reverse gear row 82 is provided so as to mesh with the second output gear 82a provided so as to be rotatable relative to the output shaft 44 via the second output gear 82a and the idler gear 82c so as to rotate integrally with the auxiliary shaft 43. It is composed of the 6th auxiliary gear 82b.

The third coupling mechanism 83 selectively rotates the first output gear 81a and the second output gear 82a integrally with the output shaft 44 by moving the third sleeve 83a in the axial direction by a gear shift actuator (not shown).

Here, the power transmission path in DCT2 will be briefly described. In the first speed, the second input gear 62a and the first input shaft 41 are connected by the first connecting mechanism 63, the first output gear 81a and the output shaft 44 are connected by the third connecting mechanism 83, and the first clutch. It is established by connecting 20. As a result, the power of the engine 10 is transmitted from the first clutch 20 in the order of the first input shaft 41, the first low speed gear train 62, the sub shaft 43, the forward gear train 81, and the output shaft 44.

In the second speed, the fourth input gear 72a and the second input shaft 42 are connected by the second connecting mechanism 73, the first output gear 81a and the output shaft 44 are connected by the third connecting mechanism 83, and the second clutch. It is established by making 30 a contact. As a result, the power of the engine 10 is transmitted from the second clutch 30 in the order of the second input shaft 42, the second low speed gear train 72, the sub shaft 43, the forward gear train 81, and the output shaft 44.

In the third speed, the first input gear 61a and the first input shaft 41 are connected by the first connecting mechanism 63, the first output gear 81a and the output shaft 44 are connected by the third connecting mechanism 83, and the first clutch. It is established by connecting 20. As a result, the power of the engine 10 is transmitted from the first clutch 20 in the order of the first input shaft 41, the first high-speed gear train 61, the sub shaft 43, the forward gear train 81, and the output shaft 44.

In the 4th speed, the 3rd input gear 71a and the 2nd input shaft 42 are connected by the 2nd connecting mechanism 73, the 1st output gear 81a and the output shaft 44 are connected by the 3rd connecting mechanism 83, and the 2nd clutch. It is established by making 30 a contact. As a result, the power of the engine 10 is transmitted from the second clutch 30 in the order of the second input shaft 42, the second high-speed gear train 71, the sub shaft 43, the forward gear train 81, and the output shaft 44.

The control device 50 includes a CPU 51, a memory 52, and an interface (not shown) that is connected to various sensors and devices to send and receive signals. The CPU 51 controls the engine 10 by executing the program stored in the memory 52, and also controls the DCT2 through the control of the hydraulic circuit 90. Specifically, by executing the program stored in the memory 52, the CPU 51 functions as a shift condition establishment determination unit 53, a transmission output torque reduction unit 54, and an execution unit 55, as shown in FIG. ..

The shift condition establishment determination unit 53 determines whether or not the shift condition is satisfied based on the accelerator opening degree Acc, the vehicle speed V, the shift map stored in the memory 52, and the like.

The transmission output torque reducing unit 54 reduces the output torque of the DCT2 by a certain amount prior to the start of gripping in each shifting.

The execution unit 55 engages and disengages the first clutch 20 and disengages the second clutch 30 via the hydraulic circuit 90, and moves the first sleeve 63a, the second sleeve 73a, and the third sleeve 83a. Perform an upshift or downshift shift.

It should be noted that it is not necessary that all of the functional units described above are realized by the control device 50, and any one or more of the functional units described above is another control device different from the control device 50. May be realized by. For example, the control device 50 may be configured to function as a shift condition establishment determination unit 53 and a transmission output torque reduction unit 54. Further, it goes without saying that any one of the above-described functional units may be configured to also serve as the function of the other functional unit.

Subsequently, the shift control by the control device of the transmission according to the present embodiment will be described in detail with reference to the flowchart of FIG.

First, the shift condition establishment determination unit 53 confirms whether or not the shift condition for upshift or downshift is satisfied (S1). Whether or not the shift condition is satisfied is determined based on the accelerator opening degree Acc, the vehicle speed V, the shift map, and the like. While it is determined that the shift condition is not satisfied (NO in S1), the determination of whether or not the shift condition is satisfied is repeated until it is determined that the shift condition is satisfied (YES in S1).

When it is determined that the shifting condition is satisfied, the output torque of the DCT2 (transmission output torque) is reduced by the transmission output torque reducing unit 54 (S2). The amount of reduction is a predetermined constant value according to the experiment, how the vehicle 1 is used, the vehicle type, and the like.

When the output torque of the DCT2 is reduced by the transmission output torque reduction unit 54, the execution unit 55 executes an upshift or downshift shift determined by the shift condition establishment determination unit 53 to satisfy the condition (S3). ). This completes the shift control.

Next, with reference to FIG. 4, which shows a time chart at the time of shifting, how the shifting progresses will be specifically described. Here, it is assumed that the upshift from the 3rd speed to the 4th speed is performed.

When the shift condition establishment determination unit 53 determines that the upshift shift condition is satisfied, first, as shown in the lower chart, the transmission output torque reduction unit 54 sets the transmission output torque up to that point. Reduce the value (driver required output torque) by a certain value.

Specifically, the transmission output torque reducing unit 54 establishes the shifting ratio and shifting conditions of the third speed, which is the shifting stage before the shifting is executed, so that the transmission output torque is reduced by a predetermined constant value. The amount of reduction in engine torque is obtained based on the engine torque when it is determined to be. When the reduction amount is obtained, as shown in the middle chart, the transmission output torque reduction unit 54 reduces the reduction amount engine torque and reduces the torque capacity of the first clutch 20 that is engaged during the execution of the third speed. Reduce so that it is equal to the reduced engine torque.

Further, it is preferable to reduce the constant value of the transmission output torque so as not to give a sense of discomfort to the driver. That is, the reduction of the transmission output torque prior to the re-grabbing of the two clutches is performed at a changing speed so that the jerk of the vehicle 1 during the reduction does not become a value that gives the driver a sense of discomfort. Is preferable. For example, the transmission output torque reducing unit 54 reduces the transmission output torque so as to satisfy the following formula 1. The jerk referred to here is a forward jerk, which is a jerk in the traveling direction of the vehicle 1.

In Equation 1, _{r w} is the tire radius, _{i f} the final gear ratio, symbol ^ w m is the vehicle weight, the symbol ^ with _{F aero} air resistance estimation value, the symbol ^ with _{F roll} is rolling estimate, g is the gravitational Acceleration and θ with the symbol ^ are gradient estimates. It should be noted that these parameters can be determined in advance or can be obtained by a method known at the time of filing the application of the present application. Therefore, detailed description will be omitted.

Further, in Equation 1, the symbol ... means the first-order time derivative, and the symbol ... means the second-order time derivative. _Toi is the transmission output torque. Therefore, _{the first-order time derivative value of Toi} means the rate of change of the transmission output torque. Further, v _x is the forward speed of the vehicle 1. Therefore, the second-order time derivative means the forward jerk of the vehicle 1.

As _{a range of suitable values of the second-order time derivative value of v x} (front jerk of vehicle 1), a range of values that the driver does not feel uncomfortable is experimentally obtained in advance and stored in the memory 52. Therefore, by substituting such a value into Equation 1 and changing the transmission output torque at a change speed within the numerical range obtained, the transmission output can be performed prior to re-grabbing the clutch without giving a sense of discomfort to the driver. The torque can be reduced.

Subsequently, as shown in the middle chart, the execution unit 55 gradually increases the torque capacity of the second clutch 30 while gradually reducing the torque capacity of the first clutch 20. That is, the clutch is re-grasped.

As a result, as shown in the lower chart, the output torque of the first clutch system, which is the torque transmitted to the output shaft 44 via the first clutch 20 and the first transmission unit 60, gradually decreases. Further, the output torque of the second clutch system, which is the torque transmitted to the output shaft 44 via the second clutch 30 and the second transmission unit 70, gradually increases. The transmission output torque, which is the torque output from the output shaft 44, is the sum of the first clutch system output torque and the second clutch system output torque. The execution unit 55 controls the torque capacity of each clutch while maintaining a state in which the transmission output torque is reduced by a predetermined constant value with respect to the driver required output torque.

When the output torque of the first clutch system becomes 0 and the output torque of the transmission becomes equal to the output torque of the second clutch system, the execution unit 55 controls as follows. That is, as shown in the middle chart, the execution unit 55 maintains the torque capacity of the second clutch 30 at the engine torque when the clutch is being re-grasped for a predetermined time, and determines the engine torque. Quantitative reduction. As a result, as shown in the upper chart, the engine speed changes from the speed of the first input shaft 41 to the speed of the second input shaft 42. When the engine speed matches the speed of the second input shaft 42, no slippage occurs in any of the clutches.

When the engine speed matches the speed of the second input shaft 42, the execution unit 55 increases the torque capacity of the second clutch 30 by a predetermined amount so as not to cause slippage, as shown in the middle chart. It also restores the engine torque to the driver-required engine torque. As a result, the 4th speed is achieved and the shift is completed.

During the shift execution, the first clutch 20 and the second clutch 30 are slipping in the step of re-grabbing the first clutch 20 and the second clutch 30. Further, in the transition process of the engine speed, the second clutch 30 is slipping. However, the torque capacity of each clutch is reduced throughout these steps. Therefore, the energy absorbed by each clutch is reduced, and the amount of heat generated by each clutch is also reduced. That is, according to the transmission control device according to the present embodiment, it is possible to prevent excessive heat generation in each clutch. Moreover, since the clutch re-grabbing step and the engine speed transition step are performed in a state where the transmission output torque, which is the output torque of the DCT2, is reduced, the amount of heat generated in each clutch can be reduced more reliably. ..

Further, prior to the gripping, the transmission output torque is reduced by a predetermined constant value, and the state is continued through the gripping step and the engine speed transition step. Therefore, it is possible to prevent the driver from unexpected fluctuations in the vehicle jerk during one shift.

Moreover, according to the transmission control device according to the present embodiment, the amount of reduction of the transmission output torque with respect to the driver-required output torque does not change with each shift, but is always constant. Therefore, it is possible to equalize the degree of change in the acceleration of the vehicle given to the driver at the time of shifting. That is, it is possible to prevent a decrease in drivability due to giving a different acceleration / deceleration feeling to the driver each time the gear is changed.

The transmission control device according to the present embodiment can also be applied in the case of downshifting. FIG. 5 is a time chart when the downshift from the 3rd speed to the 2nd speed is executed.

When the downshift is executed, the transmission output torque is reduced by a certain value from the previous value (driver required output torque) prior to the clutch re-grabbing, as in the case where the upshift is executed. In that state, the engine speed transition step and the gripping step are executed. Therefore, as in the case where the upshift is executed, it is possible to prevent excessive heat generation in each clutch and prevent deterioration of drivability.

The automatic transmission may be a DCT having a larger number of gear trains and capable of shifting in more stages, a clutch that stops the relative rotation of the elements constituting the planetary gear, and a clutch that stops the rotation of the elements. It may be an automatic transmission provided with a brake to be operated.

According to the present invention, automatic transmission capable of performing shift control capable of preventing deterioration of drivability while preventing excessive heat generation of the friction fastening element when re-grasping the friction fastening element. A control device for the machine can be provided. Therefore, its industrial applicability is enormous.

1 vehicle 2 DCT
10 Engine 11 Engine output shaft 20 1st clutch 21 1st input side clutch plate 22 1st output side clutch plate 23 1st piston 30 2nd clutch 31 2nd input side clutch plate 32 2nd output side clutch plate 33 2nd piston 40 Transmission 41 1st input shaft 42 2nd input shaft 43 Sub shaft 44 Output shaft 50 Control device 51 CPU
52 Memory 53 Shift condition satisfaction determination unit 54 Transmission output torque reduction unit 55 Execution unit 60 1st transmission unit 61 1st high-speed gear train 61a 1st input gear 61b 1st sub-gear 62 1st low-speed gear train 62a 2nd input gear 62b 2nd sub gear 63 1st connecting mechanism 63a 1st sleeve 70 2nd transmission 71 2nd high speed gear row 71a 3rd input gear 71b 3rd sub gear 72 2nd low speed gear row 72a 4th input gear 72b 4th sub Gear 73 2nd coupling mechanism 73a 2nd sleeve 80 Forward / backward switching part 81 Forward gear row 81a 1st output gear 81b 5th auxiliary gear 82 Reverse gear row 82a 2nd output gear 82b 6th auxiliary gear 82c Idler gear 83 3rd coupling mechanism 83a 3rd sleeve 101 Accelerator opening sensor 102 Engine rotation speed sensor 103 Vehicle speed sensor 90 Hydraulic circuit

Claims (2)

A shift condition establishment determination unit that determines whether or not the shift condition of the transmission for a vehicle that shifts with the re-grasping of a plurality of friction fastening elements and the transition of the engine speed is satisfied.
When it is determined by the shift condition establishment determination unit that the shift condition is satisfied , the torque capacity and engine torque of the friction fastening elements released prior to the re-grasping of the plurality of friction fastening elements and the transition of the engine speed. Is provided with a transmission output torque reducing unit that reduces the output torque of the transmission by a certain amount .
The plurality of friction engaging elements include a first friction engaging element having a first input side clutch plate and a first output side clutch plate, and a second friction engaging element having a second input side clutch plate and a second output side clutch plate. And have
The first input side clutch plate and the second input side clutch plate are connected so as to rotate integrally with the engine output shaft.
The first output side clutch plate is connected so as to rotate integrally with the first input shaft of the transmission.
The second output side clutch plate is connected so as to rotate integrally with the second input shaft of the transmission.
The engine speed is determined from the rotation speed of one of the first input shaft and the second input shaft when the first friction fastening element and the second friction fastening element are re-grasped. An automatic transmission control device that transitions to the number of revolutions of. The transmission output torque reducing unit changes the jerk of the vehicle while reducing the output torque of the transmission to be within a predetermined range predetermined so that the driver of the vehicle does not feel uncomfortable. The first aspect of claim 1, wherein the output torque of the transmission is reduced at a speed, and then the output torque of the transmission is maintained in a state of being reduced by a certain amount through the jerk re-grabbing step and the engine speed transition step. Automatic transmission control device.

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