JP2007263130A - Control device of transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a continuously variable transmission capable of accurately discriminating the connection state of a clutch when an accelerator pedal is not stepped on. <P>SOLUTION: The control device comprises a forward/reverse selecting clutch 30 arranged between an engine 70 and a CVT transmission part 40. If the primary pulley rotational speed Npri is higher than an engine rotational speed Ne with no accelerator pedal 55 stepped on, a forward clutch 32 is judged to be released in the forward/reverse selecting clutch 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission control device.

  In a forward / reverse switching clutch that switches the power transmission state between input rotation and output rotation according to the clutch engagement state, the manual valve is moved based on the driver's operation of the shift lever, and the hydraulic pressure supplied to the clutch is controlled to operate the clutch. The power transmission state is switched by fastening or releasing.

If the accelerator pedal is depressed without the clutch engaged, the power is not transmitted, so the engine rotation speed, which is the input side rotation speed, is abrupt compared to the primary pulley rotation speed, which is the output side rotation speed. Ascending, so-called engine blow occurs. Therefore, when the engine blows idle, it is determined whether the clutch is engaged or disengaged by comparing the rotational speed on the input side of the clutch with the rotational speed on the output side of the clutch, that is, the engaged state of the clutch. Japanese Patent Application Laid-Open No. 2004-133867 discloses a device that performs protection control.
Japanese Patent Laid-Open No. 2004-267341

  However, in the above-described invention, there is a problem that when the accelerator pedal is not depressed by the driver during traveling, the engine is not blown and the clutch engagement state cannot be determined.

  Therefore, in the above invention, appropriate protection control cannot be performed without the accelerator pedal being depressed, and protection control is always performed when the protection control is performed even when the accelerator pedal is not depressed. Therefore, excessive protection control must be performed.

  The present invention has been invented to solve such problems, and it is an object of the present invention to determine the engagement state of a clutch when the accelerator pedal is not depressed during traveling and to perform appropriate protection control. .

  In the present invention, the engine, a transmission that changes the gear ratio and transmits the driving force, a first rotating element that is disposed between the transmission and the engine and is connected to the transmission, and the first that is connected to the engine. A clutch engagement device that switches a power transmission state between the two rotation elements according to the engagement state of the clutch, and an output rotation speed detection unit that detects an output rotation speed from the transmission; Accelerator pedal depression determination means for determining whether or not the accelerator pedal is depressed, first rotation speed detection means for detecting the rotation speed of the first rotation element, and first rotation speed for detecting the rotation speed of the second rotation element. 2 and the output rotational speed of the transmission is not less than a predetermined value, the accelerator pedal is not depressed, and the first rotational speed is greater than the second rotational speed. And a clutch connection determiner determines that releases the switch, based on the determination result of the clutch engagement determining means, for controlling the transmission.

  According to the present invention, when the accelerator pedal is not depressed, it is possible to accurately determine the engagement state of the clutch and perform appropriate protection control.

  A vehicle having a clutch engagement control device for a continuously variable transmission according to the present invention will be described with reference to the schematic diagram of FIG.

  The vehicle according to the embodiment of the present invention includes an engine 70, a hydraulic pump 10, a torque converter 20, a forward / reverse switching clutch (clutch engagement device) 30, and a CVT transmission unit (continuously variable transmission) 40.

  The engine 70 is an internal combustion engine that generates an output for driving a vehicle by burning gasoline or the like, for example.

  The torque converter 20 includes a lockup mechanism 20a that mechanically fastens the input and output shafts of the torque converter 20. The torque converter 20 can start the vehicle with the lock-up mechanism 20a released, and further dampens vibration. Further, the lockup mechanism 20a engages the input / output shafts of the torque converter 20 when the vehicle speed VSP is in the middle / high speed range, and adjusts the fastening force so that the output of the engine 70 is partially or completely forward / reversely switched. 30.

  The forward / reverse switching clutch 30 includes a planetary gear 31 that switches a power transmission path between the engine 70 side and a CVT transmission unit 40 side, which will be described later, a forward clutch 32, and a reverse brake 33. The forward clutch 32 is connected to the forward clutch piston, and is fastened by hydraulic pressure (forward clutch pressure) supplied to the forward clutch piston chamber 32a when the vehicle moves forward. When the forward clutch 32 is engaged, the turbine shaft 21b and an output shaft 41c, which will be described later, rotate together, and the output of the engine 70 is transmitted to the output shaft 41c via the torque converter 20. The reverse brake 33 is connected to the reverse brake piston, and is engaged by hydraulic pressure (reverse brake pressure) supplied to the reverse brake piston chamber 33a when the vehicle is reverse. When the reverse brake 33 is engaged, the turbine shaft 21b and the input shaft 41c rotate at a rotational speed corresponding to the gear ratio of the planetary gear 31, and the output of the engine 70 is transmitted to the input shaft 41c via the torque converter 20. Further, no hydraulic pressure is supplied at the neutral position (neutral or parking), and both the forward clutch 32 and the reverse brake 33 are released.

  The forward clutch 32 and the reverse brake 33 are exclusively engaged, and at the time of forward movement, the forward clutch pressure is supplied to fasten the forward clutch 32, and the reverse brake pressure is connected to the drain to release the reverse brake 33. . On the other hand, at the time of reverse travel, the forward clutch pressure is connected to the drain, the forward clutch 32 is released, the reverse brake pressure is supplied, and the reverse brake 33 is engaged. In the neutral position, the forward clutch pressure and the reverse brake pressure are connected to the drain, and both the forward clutch 32 and the reverse brake 33 are released. In this embodiment, when the forward clutch 32 is engaged, the input rotational speed to the forward / reverse switching clutch 30 and the output rotational speed from the forward / reverse switching clutch 30 are the same speed. There is no speed change by the switching clutch 30. When the reverse brake 33 is engaged, the input rotational speed to the forward / reverse switching clutch 30 and the output rotational speed from the forward / reverse switching clutch 30 are changed according to the gear ratio of the planetary gear 31. .

  The CVT transmission unit 40 includes a primary pulley 41, a secondary pulley 42, and a V belt 43.

  The primary pulley 41 is an input shaft side pulley through which the driving force of the engine 70 is input via the torque converter 20, the forward / reverse switching clutch 30, and the input shaft 41c. The primary pulley 41 has a fixed conical plate 41a that rotates integrally with the input shaft 41c, a V-shaped pulley groove that is disposed opposite to the fixed conical plate 41a, and a hydraulic pressure that acts on the primary pulley (hereinafter referred to as the primary pulley). And a movable conical plate 41b that can be displaced in the axial direction by “primary pressure”. The primary pulley rotational speed Npri of the primary pulley 41 is detected by a primary pulley rotational speed sensor 41d.

  The secondary pulley 42 transmits the driving force transmitted by the V belt 43 to the driving wheel 80 via an idler gear or a differential gear. The secondary pulley 42 has a fixed conical plate 42a that rotates integrally with the output shaft 42c, a V-shaped pulley groove disposed opposite to the fixed conical plate 42a, and a hydraulic pressure that acts on the secondary pulley 42 ( (Hereinafter referred to as “secondary pressure”) and a movable conical plate 42b that can be displaced in the axial direction. In addition, the pressure receiving area of the secondary pulley and the pressure receiving area of the primary pulley are the same or almost the same. The secondary pulley rotational speed Nsec of the secondary pulley 42 is detected by a secondary pulley rotational speed sensor 42d. The vehicle speed VSP is calculated from the secondary pulley rotation speed Nsec.

  The V belt 43 is wound around the primary pulley 41 and the secondary pulley 42, and transmits the driving force input to the primary pulley 41 to the secondary pulley 42.

  The hydraulic pump 10 is driven by the engine 70 to pump oil. The oil pumped by the hydraulic pump 10 is regulated by the line pressure regulator 11. The hydraulic pressure adjusted by the line pressure adjusting device 11 is further adjusted by the primary pressure adjusting device 12 and the secondary pressure adjusting device 13 and supplied to the primary pulley 41 and the secondary pulley 42. Operate and shift. The hydraulic pressure branched by the line pressure adjusting device 11 is sent to the forward clutch piston chamber 32a and the reverse brake piston chamber 33a via the clutch pressure adjusting device 14 and the manual valve 57, and the forward clutch 32 or the reverse brake 33 is engaged. To control.

  The control unit 60 receives signals from the primary pulley rotational speed sensor 41d and the secondary rotational speed sensor 42d, calculates the current gear ratio from these signals, and controls the primary pressure and the secondary pressure so that the desired gear ratio is obtained. To do. Further, a signal indicating the depression amount of the accelerator pedal 55 is input, and the output of the engine 70 is controlled. Further, the engaged state of the forward clutch 32 and the reverse brake 33 is determined by clutch engagement determination control described later.

  Next, clutch engagement determination and protection control when the accelerator pedal 55 is depressed will be described with reference to the flowchart of FIG. Here, clutch engagement determination control and protection control of the forward clutch 32 will be described, and the reverse brake 33 is not engaged.

  In step S100, it is determined whether or not the accelerator pedal 55 is depressed. If the accelerator pedal 55 is depressed, the process proceeds to step S101. If the accelerator pedal 55 is not depressed, the present control is terminated.

  In step S101, the primary pulley rotation speed sensor 41d detects the primary pulley rotation speed Npri.

  In step S102, the engine rotation speed Ne is detected by the crank angle sensor 71 attached to the engine 70.

  In step S103, the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is calculated, that is, the engine rotational speed Ne that is the input rotational speed to the forward / reverse switching clutch 30 and the output rotational speed from the forward / reverse switching clutch 30. A deviation from a certain primary pulley rotational speed Npri is calculated. Then, the deviation between the engine rotation speed Ne and the primary pulley rotation speed Npri is compared with the predetermined deviation N1, and if the deviation between the engine rotation speed Ne and the primary pulley rotation speed Npri is greater than the predetermined deviation N1, Proceeding to step S104, when the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is smaller than the predetermined deviation N1, this control is terminated. The predetermined deviation N1 is a value corresponding to a change in rotational speed caused by the torque converter 20 when the lock-up mechanism 20a of the torque converter 20 is not fastened, and is a value set in advance through experiments or the like. In this embodiment, the maximum change amount between the input rotation speed and the output rotation speed in the torque converter 20 that occurs when the torque converter 20 does not fasten the lock-up mechanism 20a.

  When the forward clutch 32 is released, power is not transmitted by the forward / reverse switching clutch 30, so even when the accelerator pedal 55 is depressed and the engine rotational speed Ne increases, the primary pulley rotational speed Npri. Will not grow. In step S103, the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is compared with a predetermined deviation N1, and if the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is greater than the predetermined deviation N1, the process advances. It is determined that the clutch 32 is released, the forward / reverse switching clutch 30 is neutral, and the engine 70 is idling. Further, when the deviation between the engine rotation speed Ne and the primary pulley rotation speed Npri is smaller than the predetermined deviation N1, it is determined that the forward clutch 32 is engaged. Thereby, for example, even when the inhibitor switch 56 is out of order, the engaged state of the forward clutch 32 can be accurately determined.

  In step S104, engine torque down control for restricting the upper limit value of the engine torque is performed, and hydraulic control for limiting the forward clutch pressure to the intermediate hydraulic pressure when the forward clutch 32 is engaged next time is performed. When the accelerator pedal 55 is depressed and the engine 70 blows idle, for example, the position of the select lever 51 is in the N range. After that, when the select lever 51 is operated, the position of the select lever 51 becomes the D range, and when the forward clutch 32 is fastened, the forward clutch 32 is suddenly fastened, which may cause deterioration of the belt and the pulley. Therefore, in preparation for fastening of the forward clutch 32, for example, the fuel injection amount and ignition timing are adjusted in the engine 70, and the upper limit value of the engine torque is regulated, thereby suppressing deterioration of the belt and pulley caused by the fastening of the forward clutch 32. can do. In addition, when the forward clutch 32 is engaged next time, excessive torque is input to the primary pulley 41 by restricting the intermediate clutch hydraulic pressure at which the forward clutch 32 slips without completely engaging the forward clutch 32. This prevents the belt and pulley from deteriorating. Note that either engine torque down control or hydraulic control may be performed.

  When the accelerator pedal 55 is depressed by the above control, the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is calculated, and the deviation is compared with a predetermined deviation N1, whereby the forward clutch 32 is engaged. The state can be accurately determined. If it is determined that the forward clutch 32 is released, the forward clutch 32 is engaged by engine torque down control and hydraulic control that limits the clutch pressure to an intermediate pressure in preparation for the subsequent engagement of the forward clutch 32. The shock caused by the engagement of the forward clutch 32 can be alleviated.

  Although the engagement control of the forward clutch 32 has been described here, the same applies to the engagement control of the reverse brake 33. In this case, when the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is calculated in step S103, the engine rotational speed Ne, the primary rotational speed Npri or the predetermined deviation N1 is set according to the gear ratio of the planetary gear 31. To correct.

  Next, clutch engagement determination and protection control when the accelerator pedal 55 is not depressed will be described with reference to the flowchart of FIG. Here, clutch engagement determination control and protection control of the forward clutch 32 will be described, and the reverse brake 33 is not engaged.

  In step S200, the vehicle speed VSP is calculated from the secondary pulley rotation speed Nsec detected by the secondary pulley rotation speed sensor 42d, and it is determined whether the vehicle speed VSP is zero (predetermined value), that is, whether the vehicle is traveling. When the vehicle speed VSP is not zero, the process proceeds to step S201, and when the vehicle speed VSP is zero, the present control is terminated (step S200 constitutes an output rotation speed detecting means).

  In step S201, it is determined whether or not the accelerator pedal 55 is depressed. If the accelerator pedal 55 is not depressed, the process proceeds to step S202. If the accelerator pedal 55 is depressed, the present control is terminated (step S201 constitutes an accelerator pedal depression determining unit).

  In step S202, the primary pulley rotation speed sensor 41d detects the primary pulley rotation speed Npri (step S202 constitutes a first rotation speed detection means).

  In step S203, the engine rotational speed Ne is detected by the crank angle sensor 71 attached to the engine 70 (step S203 constitutes a second rotational speed detecting means).

  In step S204, it is determined whether the vehicle speed VSP is higher than a preset lockup mechanism release speed V1. When the vehicle speed VSP is higher than the lockup mechanism release speed V1, it is determined that the lockup mechanism 20a is engaged, and the process proceeds to step S205, and when the vehicle speed VSP is lower than the lockup mechanism release speed V1. Determines that the lockup mechanism 20a has been released, and proceeds to step S108 (step S204 constitutes a lockup mechanism fastening determination means).

  When the lockup mechanism 2a is in the engaged state, in step S205, the primary pulley rotational speed Npri and the engine rotational speed Ne are compared, and the state where the primary rotational speed Npri is greater than the engine rotational speed Ne continues for the predetermined time T1. Determine if you did. If the state where the primary rotational speed Npri is higher than the engine rotational speed Ne continues for the predetermined time T1, the process proceeds to step S207, and the state where the primary rotational speed Npri is higher than the engine rotational speed Ne does not continue for the predetermined time T1. If this happens, this control is terminated. In this embodiment, the predetermined time T1 is set to 1 second (step S205 constitutes a clutch engagement determination unit).

  When the lockup mechanism 20a is engaged, the accelerator pedal 55 is not depressed, and the forward clutch 32 is engaged, the engine rotational speed Ne and the primary pulley rotational speed Npri are equal to each other. Become. On the other hand, when the lock-up mechanism 20a is engaged and the accelerator pedal 55 is not depressed, for example, the select lever 51 is operated to be in the N range or the intermediate position between the D range and the N range, and the forward clutch 32 is When released and the forward / reverse switching clutch 30 becomes neutral, the primary pulley rotational speed Npri becomes larger than the engine rotational speed Ne. In this embodiment, by determining whether or not the state where the primary pulley rotational speed Npri is higher than the engine rotational speed Ne continues for a predetermined time T1, erroneous determination caused by vibration or the like when the forward clutch 32 is engaged is eliminated. The engaged state of the forward clutch 32 can be determined more accurately. Thereby, even when the inhibitor switch 56 is out of order or when the accurate position of the select lever 51 cannot be determined from the inhibitor switch 56, the engaged state of the forward clutch 32 can be accurately determined.

  On the other hand, if the lock-up clutch mechanism 2a is in the released state in step S204, in step S206, the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is calculated, that is, input to the forward / reverse switching clutch 30. A deviation between the engine rotational speed Ne, which is the rotational speed, and the primary pulley rotational speed Npri, which is the output rotational speed from the forward / reverse switching clutch 30, is calculated. Then, the deviation between the engine rotation speed Ne and the primary pulley rotation speed Npri is compared with the predetermined deviation N2, and if the deviation between the engine rotation speed Ne and the primary pulley rotation speed Npri is larger than the predetermined deviation N2, Proceeding to step S207, if the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is smaller than the predetermined deviation N2, this control is terminated. The predetermined deviation N2 is a value corresponding to a change in rotational speed caused by the torque converter 20 when the lock-up mechanism 20a of the torque converter 20 is not fastened, and is a value set in advance by experiments or the like. In this embodiment, the maximum change amount between the input rotation speed and the output rotation speed in the torque converter 20 that occurs when the torque converter 20 does not fasten the lock-up mechanism 20a.

  When the forward clutch 32 is released, power is not transmitted by the forward / reverse switching clutch 30, so even if the accelerator pedal 55 is not depressed and the engine rotational speed Ne is reduced, the primary pulley rotational speed Npri. Does not become smaller than the drop in the engine speed Ne. In step S206, the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is compared with a predetermined deviation N2, and if the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is greater than the predetermined deviation N2, the process advances. It is determined that the clutch 32 is released and the forward / reverse switching clutch 30 is neutral. When the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is smaller than the predetermined deviation N2, it is determined that the forward clutch 32 is engaged. Thereby, for example, even when the inhibitor switch 56 is out of order, the engaged state of the forward clutch 32 can be accurately determined.

  In step 206, for example, a correction value is calculated according to the primary pulley rotation speed Npri, the hydraulic pressure of the lockup mechanism 20a, and the rotation speed obtained by adding the correction value to the engine rotation speed Ne, and the primary pulley rotation speed Npri. , The engagement state of the forward clutch 32 can also be determined.

  Further, a change amount per hour of the primary pulley rotation speed Npri and a change amount per hour of the engine rotation speed Ne are calculated, and the change amount per hour of the engine rotation speed Ne is calculated per time of the primary pulley rotation speed Npri. It may be determined that the forward clutch 32 is disengaged when the amount of change is greater than.

  In step S207, engine torque down control for restricting the upper limit value of the engine torque is performed, and when the forward clutch 32 is engaged next time, hydraulic control for limiting the forward clutch pressure to the intermediate hydraulic pressure is performed. When the accelerator pedal 55 is not depressed and the primary pulley rotational speed Npri is higher than the engine rotational speed Ne for a predetermined time T1, and the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is a predetermined deviation N2. Is larger than the N range, for example, the position of the select lever 51 may be an intermediate position between the N range and the D range. After that, when the select lever 51 is operated, the position of the select lever 51 again becomes the D range, and when the forward clutch 32 is fastened, the forward clutch 32 is suddenly fastened, which may cause deterioration of the belt and the pulley. Therefore, in preparation for sudden engagement of the forward clutch 32, for example, by adjusting the fuel injection amount and ignition timing in the engine 70 and restricting the upper limit value of the engine torque, the belt and the pulley are deteriorated due to the engagement of the forward clutch 32. Can be suppressed. In addition, when the forward clutch 32 is engaged next time, excessive torque is input to the primary pulley 41 by restricting the intermediate clutch hydraulic pressure at which the forward clutch 32 slips without completely engaging the forward clutch 32. This prevents the belt and pulley from deteriorating. Note that either engine torque down control or hydraulic pressure control may be performed (step 207 constitutes torque regulation means and hydraulic pressure control means).

  Note that the engine torque down control or the like performed in step S207 ends when, for example, the vehicle speed VSP becomes zero, or when a predetermined release condition such as the elapse of a predetermined time after the engine torque down control is satisfied.

  By the above control, when the accelerator pedal 55 is not depressed during traveling, the engaged state of the forward clutch 32 can be accurately determined by comparing the primary pulley rotational speed Npri and the engine rotational speed Ne. . If it is determined that the forward clutch 32 is released, that is, the forward / reverse clutch 30 is neutral, the engine torque down control and the clutch pressure are limited to the intermediate pressure in preparation for the subsequent engagement of the forward clutch 32. By the hydraulic control, the shock caused by the sudden engagement of the forward clutch 32 can be reduced.

  Although the engagement control of the forward clutch 32 has been described here, the same applies to the engagement control of the reverse brake 33. In this case, when the deviation between the engine rotational speed Ne and the primary pulley rotational speed Npri is calculated in step S103, the engine rotational speed Ne, the primary rotational speed Npri or the predetermined deviation N1 is set according to the gear ratio of the planetary gear 31. To correct.

  In this embodiment, the engine rotational speed Ne is detected. However, the turbine rotational speed of the turbine shaft 20b may be detected and compared with the primary pulley rotational speed Npri.

  Here, changes in the primary pulley rotational speed Npri and the engine rotational speed Ne when the accelerator pedal 55 is not depressed will be described with reference to the time chart of FIG. Note that the lockup mechanism 20a is described as being fastened.

  At time t0, when the accelerator pedal 55 is not depressed during traveling, the engine rotational speed Ne and the primary pulley rotational speed Npri gradually decrease thereafter. If the forward clutch 32 is engaged at this time, the primary pulley rotational speed Npri and the engine rotational speed Ne are substantially the same rotational speed.

  At time t1, when the select lever 51 is operated and, for example, reaches an intermediate position between the N range or the D range and the N range, the hydraulic pressure of the forward clutch 32 decreases and the forward clutch 32 is released. When the forward clutch 32 is engaged, the rotation of the engine 70 is transmitted from the drive wheel 80, so the primary pulley rotational speed Npri and the engine rotational speed Ne are the same rotational speed. When is released, the power from the drive wheel 80 is not transmitted to the engine 70, so the primary pulley rotational speed Npri becomes higher than the engine rotational speed Ne.

  If the primary pulley rotational speed Npri continues to be higher than the engine rotational speed Ne from the time t1 to the time t2 when the predetermined time T1 has elapsed, the forward clutch 32 is released, that is, the forward / reverse clutch 30 is neutral. Therefore, in preparation for sudden engagement of the forward clutch 32 thereafter, engine torque down control, hydraulic control, etc. are performed. As a result, even when the accelerator pedal 55 is not depressed, the engaged state of the forward clutch 32 can be accurately detected regardless of the inhibitor switch 56, and deterioration of the belt, pulley, etc. can be suppressed.

  In this embodiment, the clutch engagement is determined by comparing the engine rotational speed Ne and the primary pulley rotational speed Npri. However, the vehicle speed VSP or the secondary pulley rotational speed Nsec is used instead of the primary pulley rotational speed Npri. It may be used. In this case, as shown in FIG. 4, since the amount of decrease in the engine rotation speed Ne is large with respect to the decrease in the vehicle speed, it is possible to determine the clutch engagement using the same concept as the primary pulley rotation speed Npri.

  Further, the determination can be made with higher accuracy by using the vehicle speed VSP or the secondary pulley rotation speed Nsec together with the primary pulley rotation speed Npri.

  In this embodiment, the continuously variable transmission has been described. However, the present invention is not limited to the continuously variable transmission, and may be used for a stepped transmission.

  The effect of the embodiment of the present invention will be described.

  When it is determined that the accelerator pedal 55 is not depressed and the lockup mechanism 20a is not engaged during traveling, and the primary pulley rotational speed Npri is greater than the engine rotational speed Ne for a predetermined time T1, the forward clutch 32 is maintained. That is, that is, it is determined that the forward / reverse clutch 30 is neutral. If it is determined that the lock-up mechanism 20a is released, it is determined that the forward clutch 32 is released when the deviation between the primary pulley rotational speed Npri and the engine rotational speed Ne exceeds a predetermined deviation N2.

  Thereby, even when the accelerator pedal 56 is not depressed, the engaged state of the forward clutch 32 can be accurately determined. For example, even when the inhibitor switch 56 fails or when the inhibitor switch 56 cannot accurately determine the engaged state of the forward clutch 32, the engaged state of the forward clutch 32 can be accurately determined. Further, since the forward clutch 32 is determined to be released when the primary pulley rotational speed Npri is higher than the engine rotational speed Ne for a predetermined time T1, it is determined that the forward clutch 32 has been released. Can be accurately determined.

  Further, when it is determined that the forward clutch 32 is released, the engine torque down control for restricting the engine torque of the engine 70, the hydraulic control for restricting the forward clutch pressure to the intermediate hydraulic pressure, and limiting to the hydraulic pressure at which the forward clutch 32 slips. I do. Thereby, the shock caused by the engagement of the forward clutch 32 can be alleviated, an excessive torque is not input to the primary pulley 41, and deterioration of the belt and the pulley can be suppressed.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

It is a schematic block diagram of the clutch fastening control apparatus of the continuously variable transmission of embodiment of this invention. It is a flowchart explaining clutch fastening determination and protection control when the accelerator pedal is depressed in the embodiment of the present invention. It is a flowchart explaining clutch fastening determination and protection control when the accelerator pedal is not depressed in the embodiment of the present invention. It is a time chart which shows the time change of the engine rotational speed in case the accelerator pedal in embodiment of this invention is not depressed, and the turbine rotational speed.

Explanation of symbols

30 Forward / reverse switching clutch 32 Forward clutch 33 Reverse brake 40 CVT transmission 51 Select lever 60 Control unit 70 Engine

Claims (4)

Engine,
A transmission that changes the gear ratio and transmits driving force;
A power transmission state between a first rotating element connected between the transmission and the engine and connected to the transmission and a second rotating element connected to the engine depends on a clutch engagement state. In a transmission control device comprising a clutch fastening device for switching,
Output rotation speed detection means for detecting an output rotation speed from the transmission;
Accelerator pedal depression determination means for determining whether or not the accelerator pedal is depressed;
First rotation speed detection means for detecting the rotation speed of the first rotation element;
Second rotational speed detecting means for detecting the rotational speed of the second rotating element;
It is determined that the clutch is released when the output rotational speed of the transmission is equal to or greater than a predetermined value, the accelerator pedal is not depressed, and the first rotational speed is greater than the second rotational speed. Clutch engagement determination means for performing,
A transmission control apparatus that controls the transmission based on a determination result of the clutch engagement determination means.   The clutch engagement determination means determines that the clutch is disengaged when a state in which the first rotation speed is higher than the second rotation speed continues for a predetermined time. A transmission control device according to claim 1.   3. The transmission according to claim 1, further comprising: a torque regulating unit that regulates a torque of a rotating element from the engine when the clutch engagement determining unit determines that the clutch is released. Control device. The clutch fastening device is configured to switch the engagement state of the clutch by hydraulic pressure, and to increase the hydraulic pressure, thereby fastening the clutch.
And a hydraulic control unit that regulates the hydraulic pressure supplied to the clutch fastening device when the clutch is judged to be released by the clutch fastening judgment unit. The transmission control device according to claim 1 or 2.