JP5483331B2 - Reverse inhibit control method for automatic transmission - Google Patents

Description

  The present invention relates to a reverse inhibit control method for an automatic transmission that is mounted on a vehicle and includes a forward clutch and a reverse clutch.

  Conventionally, in a vehicle equipped with an automatic transmission equipped with a forward clutch and a reverse clutch, when the shift selector is switched to the reverse range in order to switch to the reverse travel during the forward travel of the vehicle, the vehicle speed is equal to or higher than a predetermined vehicle speed. In this case, it is known to perform reverse inhibit control in which the forward side clutch and the reverse side clutch are disconnected to be in a neutral state.

  By the way, the driver may step on the accelerator in order to switch from the forward travel to the reverse travel and to move backward quickly. However, if the vehicle speed when switching to reverse travel is above a predetermined vehicle speed, the neutral state is established by reverse inhibit control and the engine is blown up. Then, the vehicle speed decreases while the accelerator is depressed, and the reverse clutch is automatically engaged. In such a situation, the engine speed is very high, and the clutch is damaged by the heat generated when the reverse clutch is engaged, and a large shock occurs when the clutch is engaged. Therefore, in order to reduce the damage and shock, output down control may be performed to suppress the engine speed from becoming an excessive value even when the accelerator is depressed (see, for example, Patent Document 1).

  If the reverse side clutch is engaged with the end of the reverse inhibit control while the vehicle is moving forward, the reverse side clutch is engaged in the forward coasting state, so that the reverse side clutch causes a conflict between the axle side and the engine side. The reverse torque is applied. Therefore, if the engine speed is high in such a case, further large frictional heat is generated in the reverse clutch.

  On the other hand, the amount of lubricating oil supplied to the reverse clutch is set to a minimum in order to suppress mechanical loss as much as possible. Therefore, there is a risk that the reverse clutch is not sufficiently cooled by the lubricating oil and the reverse clutch is burnt, resulting in a disadvantage in durability.

  In order to solve such a problem, it is not sufficient to perform only the output down control that suppresses the excessive increase in the engine speed when the accelerator is depressed during the reverse inhibit.

Japanese Patent Laid-Open No. 2007-177834

  The present invention pays attention to the above points, and an object thereof is to suppress an excessively high temperature of the reverse clutch and to improve the durability of the reverse clutch.

That is, the reverse inhibit control method for an automatic transmission according to the present invention is a control method for an automatic transmission that is mounted on a vehicle and includes a forward clutch and a reverse clutch, and the vehicle speed is a predetermined value while the shift selector is in the reverse range. A step of performing a control for disengaging the forward clutch and the reverse clutch and setting the neutral state to the neutral state when the neutral state is exceeded, and before setting the hydraulic pressure or amount of lubricating oil supplied to the reverse clutch to the neutral state when the neutral state is established A step of performing control to increase the amount compared to the step, a step of performing control to start engagement of the reverse clutch when the shift selector is in the reverse range and the vehicle speed falls below a predetermined value, and start of engagement of the reverse clutch And a step of performing output down control for reducing the engine speed at the time of And wherein the Rukoto.

According to such a control method, the reverse clutch can be cooled by increasing the amount of the lubricating oil during the control for disengaging the reverse clutch, compared to before the neutral state, and the reverse clutch By performing output down control for reducing the engine speed at the start of the engagement, frictional heat generated in the reverse clutch can be reduced. Therefore, the temperature increase of the reverse clutch can be effectively suppressed. In particular, the output down control is preferably performed at least from the start of engagement of the reverse clutch to the completion of engagement.

  Further, when the accelerator operation is performed during the step of disengaging the reverse clutch, if the engine further includes a step of performing output down control for reducing the engine speed, the engine speed is reduced. Thus, the frictional heat generated in the reverse clutch when the reverse clutch is engaged can be further reduced. That is, the temperature increase of the reverse clutch can be suppressed more effectively.

  According to the reverse inhibit control method for an automatic transmission according to the present invention, the temperature increase of the reverse clutch can be suppressed. Therefore, it is possible to improve the burn-in resistance of the reverse clutch.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows schematic structure of one Embodiment of this invention. The flowchart which shows the outline of the control procedure of the embodiment. Action | operation explanatory drawing which concerns on the same embodiment.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a transmission system to which the present invention is applied. The torque output from the engine 2 rotates the input shaft 30 via the drive plate 83 and the torque converter 3. The rotation of the input shaft 30 is transmitted to the drive shaft 510 via the forward / reverse switching device 4 using the planetary gear mechanism 41, and rotates the driven shaft 520 through a shift in the CVT 5. An output gear 524 is fixed to the driven shaft 520, and this output gear 524 meshes with the ring gear of the differential device 6 to rotate the output shaft 60 and thus a driving wheel (not shown). Here, in this embodiment, the forward / reverse switching device 4, the CVT 5, and the differential device 6 function as an automatic transmission of the present invention, and the forward / backward switching device 4, the CVT 5, and the differential device 6 are not shown in the figure. It is housed in the machine case.

  The forward / reverse switching device 4 includes the planetary gear mechanism 41, a reverse brake 48, and a direct coupling clutch 49. The sun gear 42 of the planetary gear mechanism 41 is connected to the input shaft 30, and the ring gear 43 is connected to the drive shaft 510. The planetary gear mechanism 41 is a single pinion system. The reverse brake 48 is provided between the carrier 45 that supports the pinion gear 44 and the transmission case. The direct coupling clutch 49 is provided between the carrier 45 and the sun gear 42. Both the reverse brake 48 and the direct coupling clutch 49 are formed using a hydraulic clutch mechanism. Here, when the direct clutch 49 of the forward / reverse switching device 4 is released and the reverse brake 48 is engaged, the driving force input from the torque converter 3 is reversely and decelerated and transmitted to the drive shaft 510, and the forward drive state is established. Become. That is, the reverse brake 48 is the forward clutch of the present invention. Conversely, when the reverse brake 48 is released and the direct clutch 49 is engaged, the carrier 45 and the sun gear 42 of the planetary gear mechanism 41 rotate together, so that the driving force input from the torque converter 3 is directly applied to the drive shaft 510. This is transmitted to the reverse drive state. That is, the direct coupling clutch 49 is a reverse side clutch of the present invention.

  The CVT 5 is a well-known belt type having a driving pulley 51 and a driven pulley 52, and a belt 53 wound around the pulleys 51 and 52 as elements. That is, both the driving pulley 51 and the driven pulley 52 have a fixed sheave fixed to the pulley shaft and a movable sheave supported so as to be displaceable in the axial direction, and the gear ratio is changed by displacing the movable sheave. It can be changed steplessly.

  The hydraulic control device 9 includes at least a solenoid valve 9a that supplies the reverse brake 48 and the direct clutch 49 and a solenoid valve 9b that controls a line pressure and supplies a desired lubricating pressure. The solenoid valve 9a includes a switching valve 10 that switches the supply destination to the reverse brake 48 or the direct coupling clutch 49 in conjunction with the shift selector operation. Further, the lubricating oil controlled by the line pressure solenoid valve 9 b is supplied to the direct coupling clutch 49 through an unillustrated axial core oil passage of the input shaft 30 inside the forward / reverse switching device 4.

  The engine 2, the hydraulic control device 9 and the like are controlled by the electronic control device 1. The electronic control device 1 is a microcomputer system including a CPU, a RAM, a ROM, an I / O interface, and the like. The control program is stored in the ROM in advance, and when executed, it is read from the ROM into the RAM and decoded by the CPU.

  The electronic control unit 1 includes a rotational speed signal 71 output from a sensor that detects an engine rotational speed Ne, a shift state signal 72 output from a sensor that detects the position of a shift selector (not shown), which is a shift lever in a normal vehicle, Reference is made to a vehicle speed signal 73 and the like output from a sensor for detecting the vehicle speed v.

  Further, the electronic control unit 1 inputs a fuel injection signal and an ignition signal to the fuel injection valve and the spark plug of the engine 2 and controls the opening degree of the solenoid valves 9a and 9b to the hydraulic control unit 9. Input a control signal.

Therefore, in this embodiment, when the shift selector is switched to the reverse range (hereinafter referred to as the R range), the electronic control device 1 executes the following reverse inhibit control program. The reverse inhibit control program shift selector is in the R range and the vehicle speed v is equal to or a predetermined vehicle speed v _th or more, the shift selector is in the R range and the vehicle speed v is in a predetermined vehicle speed v _th or In this case, in order to suppress seizing of the direct clutch 49, reverse inhibit control for cutting the direct clutch 49 into a neutral state and output down control for suppressing the engine speed Ne to a predetermined threshold, that is, a predetermined speed Ne _th or less. And a control for increasing the amount of lubricating oil supplied to the direct coupling clutch 49 as compared with that before performing the reverse inhibit control . Here, in this reverse inhibit control program, the lubricating oil increase flag F1 takes the value 1 when the amount of lubricating oil to be supplied into the forward / reverse switching device 4 is being increased, and takes the value 0 otherwise. and, if the case the engine speed Ne is executing control to suppress below a predetermined rotational speed Ne _th value 1, otherwise utilizes the output down flag F2 take a value 0. The initial values of the lubricating oil increase flag F1 and the output down flag F2 are both set to 0.

  Hereinafter, the procedure of processing performed by the reverse inhibit control program will be described with reference to FIG. 2 which is a flowchart.

First, in step S1, it is determined whether or not a condition for performing reverse inhibit control is satisfied. Specifically, it is determined whether or not the vehicle speed v exceeds a predetermined vehicle speed _vth . If the vehicle speed v exceeds the predetermined vehicle speed v _th , the process proceeds to step S2. On the other hand, when the vehicle speed v does not exceed the predetermined vehicle speed v _th, the process proceeds to step S5.

  In step S2, reverse inhibit control, that is, control for disengaging the reverse brake 48 and the direct coupling clutch 49 so as to be in the neutral state is performed.

  In step S3, it is determined whether or not the value of the lubricating oil increase flag F1 is zero. When the value of the lubricating oil increase flag F1 is 0, that is, when the amount of the lubricating oil is not increasing, the process proceeds to step S4. When the value of the lubricating oil increase flag F1 is 1, that is, when the amount of the lubricating oil is being increased, the process returns to step S1.

  In step S4, control is performed to increase the amount of lubricating oil to be supplied into the forward / reverse switching device 4 to cool the direct clutch 49, that is, the opening of the solenoid valve 9b is increased to lubricate the forward / reverse switching device 4. Control is performed to increase the line pressure of the flow path for supplying oil, and the value of the lubricating oil increase flag F1 is set to 1. Then, the process returns to step S1.

  In step S5, a direct clutch engagement start command for starting the engagement of the direct clutch 49 is issued.

  In step S6, it is determined whether or not the value of the lubricating oil increase flag F1 is 1. When the value of the lubricating oil increase flag F1 is 1, that is, when the amount of the lubricating oil is being increased, the process proceeds to step S7. When the value of the lubricating oil increase flag F1 is not 1, that is, when the amount of the lubricating oil is not increasing, the process proceeds to step S8.

  In step S7, control for ending the increase in the amount of lubricating oil to be supplied into the forward / reverse switching device 4, that is, the opening of the solenoid valve 9b and the flow path for supplying the lubricating oil into the forward / reverse switching device 4 are performed. Control is performed to return the line pressure before executing step S4, and the value of the lubricating oil increase flag F1 is reset to zero.

In step S8, and it determines whether or not the engine speed Ne is higher than the predetermined rotational speed Ne _th. When the engine speed Ne is higher than the predetermined rotational speed Ne _th, the process proceeds to step S9. When the engine speed Ne does not exceed the predetermined rotation speed Ne _th, the process proceeds to step S11.

  In step S9, it is determined whether or not the value of the output down flag F2 is zero. When the value of the output down flag F2 is 0, that is, when the output down control is not being executed, the process proceeds to step S10. When the value of the output down flag F2 is 1, that is, when the output down control is being executed, the process returns to step S8.

In step S10, the value of the output down flag F2 is set to 1, and output down control is started. Then, the process returns to step S8. As the output down control, specifically, control for cutting fuel when the engine speed Ne exceeds a predetermined speed _Neth , control for reducing the opening of the electromagnetic throttle valve, and the like can be considered.

  The engagement operation of the direct coupling clutch 49 is performed in parallel with steps S6 to S10 of this inhibit control program in response to the direct clutch engagement start command in step S5 of this inhibit control program.

  Further, by executing steps S8, S9, and S10 described above, the output torque of the engine 2 is reduced at least from the start of engagement of the direct coupling clutch 49 to the completion of engagement.

  In step S11, it is determined whether or not the value of the output down flag F2 is 1. When the value of the output down flag F2 is 1, that is, when the output down control is being executed, the process proceeds to step S12. When the value of the output down flag F2 is not 1, that is, when the output down control is not being executed, the forward / reverse switching device control control program is temporarily terminated.

  In step S12, the output down control is once ended, and the value of the output down flag F2 is reset to zero.

  During the execution of steps S1 to S4 of the reverse inhibit control program, when the accelerator pedal is operated, the fuel is cut to reduce the engine speed Ne.

That is, as shown in FIG. 3, when the shift selector is switched to the R range when the vehicle speed v is equal to or higher than the predetermined vehicle speed v _th at time t1, the condition for performing the reverse inhibit control is satisfied in step S1. It is determined that Therefore, since the initial value of the lubricating oil increase flag F1 is 0, first, the control of step S2, step S3, and step S4 is sequentially performed and supplied to the forward / reverse switching device 4 to cool the direct clutch 49. Control for increasing the amount of lubricating oil to be performed is started as compared with before the reverse inhibit control is performed, and the value of the lubricating oil increase flag F1 is set to 1. Thereafter, while the vehicle speed v is _{equal to} or higher than the predetermined vehicle speed v _th , that is, in the time zone from time t1 to time t2 in FIG. 3, the control of step S1, step S2, and step S3 is repeated, and the direct clutch 49 is cooled. Control to increase the amount of lubricating oil to be supplied into the forward / reverse switching device 4 as compared with before the reverse inhibit control is continued. Then, when the vehicle speed v falls below the predetermined vehicle speed v _th at time t2, the control shifts from the control of step S1 to the control of step S5, and a direct clutch engagement start command for starting the engagement of the direct clutch 49 is issued. Then, in step S6, it is determined that the value of the lubricating oil increase flag F1 is 1. When step S7 is executed, the value of the lubricating oil increase flag F1 is reset to 0 and should be supplied to the forward / reverse switching device 4. The control for increasing the amount of the lubricating oil as compared with that before the reverse inhibit control is completed. Thereafter, when the step S8 the engine rotational speed Ne is determined to be the predetermined rotational speed Ne _th or more, since the initial value of the output down flag F2 is 0, the control of step S9 and step S10 are sequentially performed, directly Output down control is started to suppress the engine speed Ne to a predetermined speed _Neth or less in order to reduce the frictional heat generated in the clutch 49, and the value of the output down flag F2 is set to 1. Thereafter, while the engine speed Ne is equal to or higher than the predetermined speed Ne _th , that is, in the time period from time t2 to time t3 in FIG. 3, the control of step S8 and step S9 is repeated, and the engine speed Ne is rotated to the predetermined speed. The output down control that suppresses the number _Neth or less is continued. That is, the output down control is continued at least from the start of engagement of the direct coupling clutch 49 to the completion of engagement. When the engine speed Ne falls below the predetermined engine speed Ne _th at time t3, the process _proceeds from the control in step S8 to the control in step S11. In step S11, it is determined that the value of the output down flag F2 is 1. S12 is executed, the value of the output down flag F2 is reset to 0, and the output down control is once ended.

As described above, according to the reverse inhibit control method according to the present embodiment, the direct coupling clutch 49 is cooled by the lubricating oil, and immediately after the direct coupling clutch 49 starts to be engaged, the engine speed Ne is set to the predetermined rotation. By suppressing the frictional heat generated in the direct coupling clutch 49 by suppressing it to several _Net or less, an excessive temperature rise of the direct coupling clutch 49 of the forward / reverse switching device 4 can be suppressed.

  In the present embodiment, during the execution of steps S1 to S4 of the forward / reverse switching device control program, when the accelerator pedal is operated, output down control is performed to reduce the engine speed Ne. Therefore, heat generation due to friction generated in the direct clutch 49 can be suppressed also from this point, and therefore, an excessive temperature rise of the direct clutch 49 of the forward / reverse switching device 4 can be suppressed more effectively.

  The present invention is not limited to the embodiment described above.

  For example, instead of the forward / reverse switching device and the CVT in the above-described embodiment, a known automatic transmission configured using a planetary gear train may be employed. In this case, the control method according to the present invention is applied, with the clutch that is engaged during reverse travel being used as the reverse clutch according to the present invention.

  Further, during the execution of the control for increasing the amount of lubricant to be supplied to the reverse clutch, the output cut control for reducing the engine speed is not necessarily performed.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Control apparatus 4 ... Forward / reverse switching device 48 ... Reverse brake (forward clutch)
49 ... Direct coupling clutch (reverse clutch)
9 ... Hydraulic control device

Claims (2)

A method for controlling an automatic transmission that is mounted on a vehicle and includes a forward clutch and a reverse clutch,
When the shift selector is in the reverse range and the vehicle speed exceeds a predetermined value, the step of performing control to disconnect the forward side clutch and the reverse side clutch to the neutral state;
Performing a control to increase the hydraulic pressure or amount of lubricating oil supplied to the reverse clutch when it is in the neutral state as compared to before the neutral state ;
Performing a control to start engagement of the reverse side clutch when the shift selector is in the reverse range and the vehicle speed falls below a predetermined value;
A reverse inhibit control method for an automatic transmission, comprising a step of performing an output down control for reducing the engine speed when starting the engagement of the reverse clutch.   2. The method according to claim 1, further comprising a step of performing an output down control for reducing the engine speed when an accelerator operation is performed during the execution of the step of disengaging the forward clutch and the reverse clutch to enter the neutral state. Reverse inhibit control method for automatic transmissions.

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