JP2010139074A - Device for diagnosing belt nipping force adjusting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a misdiagnosis, and to accurately diagnose a belt nipping force adjusting mechanism in a continuously variable transmission. <P>SOLUTION: A target variable speed ratio RATIOT in a lower region than a predetermined variable speed ratio (c) is a precondition for diagnosing the belt nipping force adjusting mechanism (S102). The region of RATIOT<c is a region outside a region that can be reached during the failure of a solenoid valve. In the case of the target variable speed ratio RATIOT≥c (No in S102), the belt nipping force adjusting mechanism is not diagnosed. Consequently, a misdiagnosis of being normal is not made even in the failure of the solenoid valve. In the case of RATIOT<c, when such a state occurs that an actual variable speed ratio cannot get close to the target variable speed ratio RATIOT (DWDLPR<e) during the execution of control to reduce a variable speed ratio (Yes in S104), a failure is determined (S106). In a region of RATIOT<c, when the actual variable speed ratio can get close to the target variable speed ratio RATIOT (No in S104 and Yes in S108), it is determined to be normal (S110). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, a belt is wound around a primary sheave to which driving force is input and a secondary sheave output to the drive system, and the output is stepless by adjusting the groove width between the primary sheave and the secondary sheave by shift control. The present invention relates to a diagnostic device for a belt clamping pressure adjustment mechanism in a continuously variable transmission that changes speed.

  An apparatus for diagnosing a failure of a continuously variable transmission is known (for example, see Patent Documents 1 and 2). In order to control the gear ratio of the continuously variable transmission, it is important that the solenoid valve that adjusts the primary sheave position is functioning normally. Therefore, Patent Document 1 discloses a shift adjusting device that adjusts the primary sheave position. Diagnose the failure of two solenoid valves. Similarly, Patent Document 2 diagnoses the disconnection of the DUTY solenoid that adjusts the primary sheave position.

JP-A-60-157553 (page 7-12, FIG. 10-13) JP 2006-248371 A (pages 10-12, FIGS. 3 and 4)

  Furthermore, in the continuously variable transmission, the clamping pressure adjustment is performed so that the belt does not slip with respect to the sheave by the belt clamping pressure adjusting mechanism. In order to maintain the normal function of the continuously variable transmission, it is necessary to diagnose the belt clamping pressure adjusting mechanism.

  In other words, if the belt clamping pressure adjustment mechanism does not function normally due to a solenoid valve disconnection, etc., and the belt is clamped more than necessary, the primary sheave side will try to lower the gear ratio, i.e., upshift, the secondary sheave. If the side clamping pressure remains strong, upshifting may not be sufficient. Therefore, it is necessary to determine whether the belt clamping pressure adjustment mechanism is normal or faulty.

  In Patent Documents 1 and 2 described above, failure diagnosis of a solenoid valve that performs gear ratio adjustment on the primary sheave side is such that the actual sheave position approaches the target sheave position when the solenoid valve is controlled to the upshift side. A failure is diagnosed in a state in which the actual speed ratio cannot approach the target speed ratio.

  Diagnosing a failure of the belt clamping pressure adjustment mechanism in the same manner as in Patent Documents 1 and 2 can be considered because it is difficult to change the gear ratio. However, if the diagnosis is performed under the same conditions as in the case of the failure in the gear ratio adjustment on the primary sheave side, the adjustment on the primary sheave side will function even if the belt clamping pressure adjustment mechanism is actually abnormal. The gear ratio control may be normally performed at first glance. In such a case, even if the belt clamping pressure adjusting mechanism is out of order, it may be erroneously diagnosed as being normal.

  An object of the present invention is to provide a belt clamping pressure adjusting mechanism diagnostic device capable of diagnosing the belt clamping pressure adjusting mechanism with high accuracy by preventing the above-described erroneous diagnosis.

In the following, means for achieving the above object and its effects are described.
The belt clamping pressure adjusting mechanism diagnostic device according to claim 1, wherein the belt is wound around a primary sheave to which a driving force is input and a secondary sheave to be output to a driving system, and shift control of an actual gear ratio according to a target gear ratio. Is a diagnostic device for a belt clamping pressure adjustment mechanism in a continuously variable transmission that continuously changes the output by adjusting the groove width between the primary sheave and the secondary sheave, and is calculated by the shift control as a precondition. Precondition determining means for determining whether or not the target gear ratio exists in a region smaller than the speed ratio range that can be reached when the belt clamping pressure adjusting mechanism is faulty; and the precondition determining means When it is determined that the precondition is satisfied, the belt clamping pressure adjusting mechanism is diagnosed based on the relationship between the actual speed ratio when the speed ratio is reduced by the speed change control and the target speed ratio. Characterized in that a diagnostic means for.

  When attempting to reduce the gear ratio from the region where the gear ratio is large in the gearshift control, even if the belt clamping pressure adjustment mechanism breaks down, the gear ratio reduction will be within a certain range if the primary sheave position adjustment functions. The gear ratio can be lowered. Therefore, under the situation where the target speed ratio is controlled to be a large area, even if the belt clamping pressure adjusting mechanism fails, the actual speed ratio can be brought close to the target speed ratio. If diagnosed with a condition, a misdiagnosis will occur.

  In the present invention, as a precondition for diagnosis, the condition is that the target gear ratio is present in the smaller region. For this reason, the belt clamping pressure adjusting mechanism is not diagnosed in the region where the target gear ratio is large, so that no fault diagnosis is made even if a failure occurs.

  In the region where the target gear ratio is small, even if the diagnosis of the belt clamping pressure adjusting mechanism is executed, there is no influence on the primary sheave position adjusting side, so the relationship between the actual gear ratio when the gear ratio is reduced and the target gear ratio Therefore, it is possible to accurately determine whether a failure is determined or whether it is normal or not.

In this way, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.
Further, the region on the small side is a region on the side smaller than the speed ratio range that can be reached when the belt clamping pressure adjusting mechanism is out of order.

  As a precondition, the belt clamping pressure adjustment is performed by setting a region on the side smaller than the gear ratio range that can be reached when the belt clamping pressure adjustment mechanism is broken as a reference for determining the degree of the target gear ratio. The mechanism can be diagnosed with higher accuracy.

  According to a second aspect of the present invention, in the belt clamping pressure adjusting mechanism diagnosing device according to the first aspect, when the precondition is determined by the precondition determination means, the diagnosis means performs the shift control. When it is difficult to bring the actual gear ratio at the time of the gear ratio reduction close to the target gear ratio, the failure determination of the belt clamping pressure adjusting mechanism is made.

  As described above, the belt clamping pressure adjustment is performed by determining a failure when it is difficult to bring the actual gear ratio close to the target gear ratio while executing the control for reducing the gear ratio when the precondition is satisfied. The mechanism can be diagnosed with high accuracy.

  According to a third aspect of the present invention, in the belt clamping pressure adjusting mechanism diagnosing device according to the first aspect, when the precondition is determined by the precondition determination means, the diagnosis means performs the shift control. When the actual speed ratio when the speed ratio is reduced is in a state where the actual speed ratio can be brought close to the target speed ratio, the belt clamping pressure adjusting mechanism is determined to be normal.

  As described above, the belt clamping pressure adjustment is performed by making a normal determination when the actual transmission ratio can be brought close to the target transmission ratio while executing the control for reducing the transmission ratio when the precondition is satisfied. The mechanism can be diagnosed with high accuracy.

  According to a fourth aspect of the present invention, in the belt clamping pressure adjusting mechanism diagnostic device according to the first aspect, the diagnostic means performs the shift control when the precondition is determined to be satisfied by the precondition determination means. When it is difficult to bring the actual gear ratio close to the target gear ratio when the gear ratio is reduced, the belt clamping pressure adjusting mechanism is determined to be faulty and the actual gear ratio can be brought closer to the target gear ratio. The belt clamping pressure adjusting mechanism is sometimes judged to be normal.

By executing the failure determination and the normality determination in this way, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.
According to a fifth aspect of the present invention, in the belt clamping pressure adjusting mechanism diagnostic device according to the third or fourth aspect, the normality determination is a state in which the actual gear ratio can be brought close to the target gear ratio, and the primary sheave input is further performed. It is characterized in that the state in which the torque is larger than the reference torque and the primary sheave rotation speed is higher than the reference rotation speed is made when it continues for a predetermined time.

  As described above, the condition for determining whether the primary sheave is larger than the reference torque and the primary sheave rotation speed is higher than the reference rotation speed and the condition of continuing for a predetermined time are added as logical products to the normal determination condition.

  In addition to the condition that the actual gear ratio can be brought close to the target gear ratio, the primary sheave input torque and the rotational speed are higher than the reference, and these continue for a predetermined time, so that during upshift control during acceleration It turns out that. As a result, it is more certain that the state is not erroneously diagnosed, and the belt clamping pressure adjusting mechanism can be diagnosed with higher accuracy.

  In the belt clamping pressure adjusting mechanism diagnostic device according to claim 6, in any one of claims 3 to 5, the diagnostic means determines whether or not the actual speed ratio and the target speed ratio are within a proximity range. The actual speed ratio can be brought close to the target speed ratio when it is within the proximity range.

  As described above, the actual speed ratio and the target speed ratio exist in the proximity range, and the actual speed ratio may be close to the target speed ratio. This makes it possible to easily execute diagnosis.

  In the belt clamping pressure adjusting mechanism diagnostic device according to claim 7, in claim 2 or 4, the diagnostic means determines whether or not the actual speed ratio and the target speed ratio are within a separation range, The state in which the state existing in the separation range continues for a predetermined time is a state in which it is difficult to approach the target gear ratio.

  As described above, the state in which the actual speed ratio and the target speed ratio exist within the separation range continues for a predetermined time, so that it may be difficult to bring the actual speed ratio close to the target speed ratio. This makes it possible to easily execute diagnosis.

  The belt clamping pressure adjusting mechanism diagnostic device according to claim 8, wherein in the region on the side where the target speed ratio is small, the speed ratio is set within a range of 1 to the minimum speed ratio. The region is smaller than the above value.

  The region on the side where the target gear ratio is small may be a region where the gear ratio is smaller than the value set in the range of 1 to the minimum gear ratio. As a result, the belt clamping pressure adjusting mechanism is not diagnosed in the region where the target gear ratio is larger than the value set in the range of 1 to the minimum gear ratio, so there is no misdiagnosis that it is normal even if it fails. Not.

Therefore, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.
The belt clamping pressure adjusting mechanism diagnostic device according to claim 9 is the belt clamping pressure adjusting mechanism diagnostic device according to any one of claims 1 to 7, wherein the region on the side where the target speed ratio is small is the minimum speed change within the speed change range of the continuously variable transmission. A region that is a ratio, or a region that includes the region and the vicinity of the minimum gear ratio.

  The region on the side where the target gear ratio is small may be a region including the minimum gear ratio within the gear range of the continuously variable transmission, or a region including the region and the vicinity of the minimum gear ratio. As a result, the belt clamping pressure adjusting mechanism is not diagnosed in a region where the target gear ratio is other than the minimum gear ratio, or in a region other than the region including the minimum gear ratio and the vicinity of the minimum gear ratio. There is no misdiagnosis as normal.

Therefore, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.
The belt clamping pressure adjusting mechanism diagnostic apparatus according to claim 10, wherein the precondition determination unit is a condition that exists in a region on the side where the target gear ratio is small as a precondition. On the other hand, a condition that exists in a region where the rotational speed of the primary sheave and the secondary sheave is high is added as a logical product condition.

  By adding the condition existing in the region where the rotational speed of the primary sheave and the secondary sheave is high as the logical product condition to the condition existing in the region where the target gear ratio is small, there is an error in detecting the gear ratio. Diagnosis can be made by using the rotation speed range without any noise. Therefore, the diagnosis of the belt clamping pressure adjusting mechanism can be made with higher accuracy.

  The belt clamping pressure adjustment mechanism diagnostic device according to claim 11, wherein the mechanism for adjusting the groove width between the primary sheave and the secondary sheave is the hydraulic cylinder by a hydraulic cylinder. The groove width is increased by increasing the volume of the working liquid, and the groove width is decreased by decreasing the volume of the working liquid by flowing out the working liquid. The shift control is performed on the hydraulic cylinders of the primary sheave and the secondary sheave. Along with the execution of the belt clamping pressure control by the hydraulic pressure, a process for adjusting the speed ratio by the supply / discharge amount of the working liquid with respect to the hydraulic cylinder of the primary sheave is executed.

  More specifically, in the continuously variable transmission in which the mechanism for adjusting the groove width functions as described above and the shift control is executed, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.

FIG. 3 is a block diagram illustrating a power transmission mechanism using the CVT according to the first embodiment. Explanatory drawing of the principal part of the hydraulic control circuit in CVT. The graph which shows the relationship between the control duty duty with respect to solenoid valve SLS, and the secondary sheave pressure POUT. The flowchart of the belt clamping pressure adjustment mechanism diagnostic process which CVT-ECU performs. The graph which shows the relationship between a primary sheave position and a gear ratio. The timing chart which shows an example of the control at the time of solenoid valve SLS normal. The timing chart which shows an example of the control at the time of solenoid valve SLS failure.

[Embodiment 1]
FIG. 1 is a block diagram showing a power transmission mechanism using a belt-type continuously variable transmission (hereinafter referred to as CVT) 2 in a vehicle to which the above-described invention is applied. An internal combustion engine 4 is provided as a rotational driving force source for traveling. Examples of the internal combustion engine 4 include a gasoline engine and a diesel engine. Here, the internal combustion engine 4 will be described as a gasoline engine (hereinafter referred to as an engine) 4.

The output of the engine 4 is transmitted from the torque converter 6 to the differential gear device 12 via the forward / reverse switching device 8, the CVT 2, and the reduction gear 10, and is distributed to the left and right drive wheels 14L, 14R.
The CVT 2 is wound around a primary sheave 2a having a variable effective diameter provided on the input shaft 16, a secondary sheave 2b having a variable effective diameter provided on the output shaft 18, and a V groove of the sheaves 2a and 2b. The transmission belt 2c is provided. With this configuration, power is transmitted through a frictional force between the transmission belt 2c and the inner wall surfaces of the sheaves 2a and 2b. The sheaves 2a and 2b are provided with an input side hydraulic cylinder 2d and an output side hydraulic cylinder 2e for changing the width of each V-groove, that is, the engagement diameter of the transmission belt 2c. With this configuration, the hydraulic control circuit 20 adjusts the amount of hydraulic oil supplied to and discharged from the hydraulic cylinders 2d and 2e, thereby changing the engagement diameter (effective diameter) of the transmission belt 2c in both sheaves 2a and 2b. It is possible to continuously change γ (= input shaft rotational speed NIN / output shaft rotational speed NOUT).

  An electronic control unit (hereinafter referred to as an ECU) 22 mainly composed of a microcomputer is composed of an engine ECU 22a that controls the engine 4 and a CVT-ECU 22b that controls CVT2. The ECU 22 receives an operation position PS signal from an operation position detection sensor 26 that detects an operation position of the shift lever 24. Further, a signal indicating the throttle opening TA from the throttle sensor 32 that detects the opening of the throttle valve 30 driven by the throttle actuator 28, and an accelerator opening ACCP from the accelerator operation amount sensor 36 that detects the opening of the accelerator pedal 34 are obtained. A signal that represents the signal (a signal that reflects the requested output amount of the driver) is input. Further, a signal representing the engine speed NE from the engine speed sensor 38, a signal representing the vehicle speed SPD from the vehicle speed sensor 40 (also serving as the output shaft speed sensor detecting the rotational speed NOUT of the output shaft 18), and the input of the input shaft 16 A signal representing the input shaft rotational speed NIN is input from the input shaft rotational speed sensor 42 for detecting the shaft rotational speed.

  In addition to this, the ECU 22 also receives signals from other sensors and switches. Here, there are a signal representing the hydraulic oil temperature in the CVT 2, a signal representing the belt clamping pressure control pressure of the secondary sheave 2 b, a signal representing the ON operation of the ignition key from the ignition switch operated by the ignition key, and the like.

  The engine ECU 22a and the CVT-ECU 22b in the ECU 22 execute arithmetic processing described in the program based on the above-described detection data, data stored in the internal memory, and communication data between the ECUs, and output based on the calculation result. Is running. The engine ECU 22a executes output torque control of the engine 4 of the vehicle so as to obtain a preferable acceleration feeling and fuel consumption, and the CVT-ECU 22b executes CVT2 shift control. In the output torque control of the engine ECU 22a, the target output torque TE of the engine 4 is determined from the relationship stored in advance, and the throttle opening degree TA is adjusted so that the target output torque TE is obtained, and the output torque of the engine 4 is increased. Be controlled. In addition, the engine ECU 22a performs fuel injection control for adjusting the valve opening time of the fuel injection valve 4a in order to supply the fuel amount necessary for combustion into each intake port and each cylinder.

  In the transmission control of the CVT-ECU 22b, the target transmission ratio RATIOT is determined from the relationship stored in advance, and the sheave position of the primary sheave 2a becomes the target transmission ratio RATIOT at the sheave position of the primary sheave 2a by operating the hydraulic control circuit 20. So that it is controlled.

  Here, FIG. 2 shows a main configuration of the hydraulic control circuit 20. The CVT-ECU 22b controls the gear ratio of the CVT 2 by giving a duty command to the two DUTY solenoids DS1, DS2 provided in the hydraulic control circuit 20. The hydraulic control circuit 20 receives hydraulic pressure supplied from an oil pump P driven by the engine 4. The hydraulic pressure from the oil pump P is regulated by the solenoid valve SLS in the line pressure valve 52 and supplied to the upshift valve 54 and the belt clamping valve 56 as the line pressure (original pressure) PL.

  When the DUTY solenoid DS1 is driven, the hydraulic pressure PIN is adjusted by the upshift valve 54, and hydraulic oil is supplied to the hydraulic cylinder 2d of the primary sheave 2a. By supplying the hydraulic oil, the groove width of the primary sheave 2a is narrowed, so that the engagement diameter of the transmission belt 2c is changed and the upshift is performed.

  On the other hand, when the DUTY solenoid DS2 is driven, the oil pressure PIN is adjusted by the doubly shift valve 58, the hydraulic oil is discharged from the hydraulic cylinder 2d of the primary sheave 2a, and the groove width of the primary sheave 2a is widened, so that the transmission belt 2c is engaged. The diameter changes, resulting in a downshift.

  A secondary sheave pressure POUT for clamping the transmission belt 2c sandwiched by the secondary sheave 2b is supplied to the hydraulic cylinder 2e of the secondary sheave 2b. The hydraulic pressure POUT is regulated by control of a solenoid valve SLS that switches the belt clamping valve 56. Specifically, as shown in the relationship of FIG. 3, the solenoid valve SLS is opened to supply a higher secondary sheave pressure POUT as the duty duty (%) is lower by duty control, and the solenoid valve SLS is closed as the duty duty is higher. A low secondary sheave pressure POUT is supplied.

  Here, a diagnostic process as a belt clamping pressure adjusting mechanism diagnostic device executed by the CVT-ECU 22b will be described. FIG. 4 shows a flowchart of the belt clamping pressure adjusting mechanism diagnosis process. This process is a process that is repeatedly executed by interruption at a constant time period. The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.

  When this process is started, first, as a precondition, the input shaft speed NIN (rpm) is equal to or higher than the predetermined speed a, the output shaft speed NOUT (rpm) is equal to or higher than the predetermined speed b, and the target speed change is performed. It is determined whether or not the ratio RATIOT is smaller than a predetermined speed ratio c (S102).

  Here, the predetermined speed ratio c is set to any value from 1 to the minimum speed ratio (0.42 here). The range of the gear ratio γ that can be realized by the CVT 2 of the present embodiment is 0.42 to 2.4, and it is determined whether or not the target gear ratio RATIOT is smaller than the predetermined gear ratio c. Is equivalent to the determination of whether or not it exists in the region on the smaller side. Here, the predetermined gear ratio c is set to 0.5. That is, the predetermined speed ratio c is set so that the area on the side where the target speed ratio is small is an area including the minimum speed ratio and its vicinity (minimum speed ratio to 0.5). In the CVT 2 of the present embodiment, the predetermined speed ratio c is 0.5, but the predetermined speed ratio c is set according to the type of the CVT 2 or according to the performance required for the vehicle.

If any one of NIN ≧ a, NOUT ≧ b, and RATIOT <c is not satisfied (NO in S102), the precondition is not satisfied, so this processing is temporarily exited.
If NIN ≧ a, NOUT ≧ b, and RATIOT <c are all satisfied (YES in S102), then the shift control amount PDS1 for the DUTY solenoid DS1 is equal to or greater than a predetermined value d, and the target sheave position and the actual sheave It is determined whether or not the position deviation DWDLPR is smaller than the separation range setting reference value e (minus) for a predetermined time tx (S104).

The condition of the shift control amount PDS1 ≧ d represents a state in which control is performed to reduce the gear ratio by narrowing the groove width in the primary sheave 2a.
The sheave position is obtained from the actual gear ratio γ according to the relationship shown in FIG. The deviation DWDLPR is the actual sheave position obtained based on the target sheave position of the primary sheave 2a obtained based on the target speed ratio RATIOT and the actual speed ratio γ calculated based on the input shaft speed NIN / output shaft speed NOUT. Is the difference.

  The separation range setting reference value e indicates the boundary of the separation range indicating that the relationship between the actual transmission ratio γ and the target transmission ratio RATIOT is separated, and the condition of DWDLPR <e is that the actual transmission ratio γ and the target transmission ratio RATIOT are Is present within the separation range, that is, a state where they are separated.

  Therefore, in step S104, the actual gear ratio RATIOT <the actual gear ratio γ is about to be reduced from the state where the target gear ratio RATIOT <the actual gear ratio γ by the actual duty command (shift control amount PDS1) to the DUTY solenoid DS1, and the target gear ratio RATIOT is still set. It is determined whether or not the state of not approaching (DWDLPR <e) has continued for a predetermined time tx.

  If PDS1 ≧ d and DWDLPR <e continue for a predetermined time tx (YES in S104), a failure determination is made (S106). That is, it is diagnosed that the solenoid valve SLS that controls the clamping pressure with respect to the transmission belt 2c is broken due to disconnection or the like and is open.

  If PDS1 <d or DWDLPR ≧ e, or if PDS1 ≧ d and DWDLPR <e has not continued for a predetermined time tx (NO in S104), then the condition for normal determination Is determined (S108). That is, the deviation DWDLPR between the target sheave position and the actual sheave position is larger than the proximity range setting reference value f (> e), the input torque TT is greater than or equal to the reference torque g, and the input shaft rotation speed NIN is the reference rotation speed n (> a) It is determined whether the above state has continued for a predetermined time ty (S108). Here, the input torque TT is an estimated input torque estimated from the operating state of the engine 4.

  The proximity range setting reference value f indicates the boundary of the proximity range indicating that the relationship between the actual speed ratio γ and the target speed ratio RATIOT can be brought close, and the condition of DWDLPR> f is that the actual speed ratio γ and This represents a state where the target gear ratio RATIOT is within the proximity range, that is, a state where the target gear ratio RATIOT is sufficiently close. TT ≧ g and NIN ≧ n indicate a state in which the torque sufficient for acceleration is applied to the CVT 2 and the rotation of the primary sheave 2a is increased. If these conditions are satisfied, it is reliably determined that the hydraulic control circuit 20 is functioning normally.

  Therefore, if the state where DWDLPR> f, TT ≧ g and NIN ≧ n continues for a predetermined time ty (YES in S108), it is determined that the solenoid valve SLS is functioning normally, and the normal determination is made. (S110).

  If DWDLPR ≦ f, TT <g, or NIN <n, or if DWDLPR> f, TT ≧ g and NIN ≧ n, the ty does not continue for a predetermined time (NO in S108), the solenoid valve Since it is not certain that SLS is functioning normally, the process is temporarily exited.

An example of this control is shown in the timing charts of FIGS. FIG. 6 shows a case where the solenoid valve SLS is normal, and FIG. 7 shows a case where the solenoid valve SLS has failed.
FIG. 6 shows a state in which the target speed ratio RATIOT decreases from the timing t0 and finally the minimum speed ratio γmin (<predetermined speed ratio c) is set. Therefore, CVT-ECU22
b increases the oil pressure PIN by duty control (shift control amount PDS1 ≧ d) for the DUTY solenoid DS1, and adjusts the actual sheave position so that the groove width of the primary sheave 2a is narrowed and approaches the target gear ratio RATIOT.

  The solenoid valve SLS is duty-controlled so that the secondary sheave pressure POUT is calculated from the relationship between the change in the gear ratio and the input torque of the primary sheave 2a in order to give an appropriate clamping pressure to the transmission belt 2c. In this case, since the groove width of the secondary sheave 2b increases, the secondary sheave pressure POUT gradually decreases.

  Then, when the oil pressure PIN for the primary sheave 2a approaches the line pressure PL, the deviation DWDLPR> f between the target sheave position and the actual sheave position becomes (t1). At this time, it is assumed that the preconditions of step S102 are already satisfied, and that the input torque TT ≧ g and the input shaft rotational speed NIN ≧ n. When this state continues for a predetermined time ty (t2), a normal determination (S110) is made.

  In FIG. 7, the target gear ratio RATIOT is decreased at timing t10, the hydraulic pressure PIN is increased by duty control (shift control amount PDS1 ≧ d) for the DUTY solenoid DS1, and the groove width of the primary sheave 2a is narrowed to reduce the target gear ratio. The actual sheave position is adjusted so as to approach RATIOT as in the case of FIG. However, the solenoid valve SLS does not function due to disconnection or the like, and the secondary sheave pressure POUT remains equal to the line pressure PL and cannot be lowered.

  For this reason, the hydraulic pressure PIN for the primary sheave 2a reaches the line pressure PL (immediately before t11). However, since the secondary sheave pressure POUT cannot be reduced due to the failure of the solenoid valve SLS, the groove width of the secondary sheave 2b cannot be increased, and the deviation DWDLPR between the target sheave position and the actual sheave position does not exceed the separation range setting reference value e. That is, the target sheave position and the actual sheave position remain largely separated. Therefore, the failure is determined by continuing the predetermined time tx while the precondition is satisfied and the shift control amount PDS1 ≧ d is satisfied (t12) (S106).

  Unlike the failure of the solenoid valve SLS, if the failure is on the DUTY solenoid DS1 side, it is difficult to reduce from a region where the gear ratio γ is large (for example, a region where γ = 1.5 or more) as shown by the broken line. Therefore, a failure determination is made when the target gear ratio RATIOT exists in a large region. Therefore, the diagnosis of the solenoid valve SLS can be performed separately from the diagnosis on the DUTY solenoid DS1 side only when the target gear ratio RATIOT is in a small region.

  In the above-described configuration, the CVT-ECU 22b corresponds to the belt clamping pressure adjusting mechanism diagnostic device, and step S102 of the belt clamping pressure adjusting mechanism diagnostic process (FIG. 4) executed by the CVT-ECU 22b is a prerequisite. Steps S104 to S110 correspond to diagnosis means in the processing as the determination means.

According to the first embodiment described above, the following effects can be obtained.
(I). When attempting to reduce the gear ratio γ in the shift control, the belt clamping pressure adjusting mechanism may fail due to disconnection of the solenoid valve SLS and the secondary sheave pressure POUT may not be controlled. Even in this case, the gear ratio γ is lowered within a considerable range if the primary sheave position adjustment is performed by the DUTY solenoid DS1 in the primary sheave side adjusting mechanism. Therefore, under a situation where the target speed ratio RATIOT should be controlled within a large range, the actual speed ratio γ can be brought close to the target speed ratio RATIOT even if the belt clamping pressure adjusting mechanism is out of order. Then it will be misdiagnosed.

  In the present embodiment, the precondition for diagnosing the belt clamping pressure adjusting mechanism is that the target transmission gear ratio RATIOT is present in the region on the smaller side, here in the region smaller than the predetermined transmission gear ratio c (S102). The region where RATIOT <c is a region deviating from the region that can be reached when the solenoid valve SLS fails, and is a region where the gear ratio γ is small.

  For this reason, in the larger region where the target gear ratio RATIOT ≧ c (NO in S102), the diagnosis of the belt clamping pressure adjusting mechanism is not performed, so that it is normal even if the solenoid valve SLS fails. Is not misdiagnosed.

  The region of RATIOT <c (YES in S102) is a region of the gear ratio γ that cannot be reached if the solenoid valve SLS is out of order. Therefore, in this target gear ratio region, when the gear shift control is executing control to reduce the gear ratio γ, if it becomes difficult for the actual gear ratio γ to approach the target gear ratio RATIOT (in S104). YES), a failure determination is made (S106).

  If the actual speed ratio γ is in a range where RATIOT <c can approach the target speed ratio RATIOT (NO in S104, YES in S108), a normal determination is made (S110).

  Thus, within the region where the target gear ratio RATIOT is divided by the predetermined gear ratio c, the diagnosis of the belt clamping pressure adjusting mechanism is not executed when RATIOT ≧ c, and the diagnosis is performed when RATIOT <c. Thus, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.

  (B). In the present embodiment, the region where the target gear ratio RATIOT is smaller is the region where the gear ratio γ is smaller than the predetermined gear ratio c set to a value between 1 and the minimum gear ratio. In the case of a failure on the DUTY solenoid DS1 side, the adjustment of the actual gear ratio γ is limited from a maximum gear ratio to a value larger than 1, for example, γ = 1.5. Therefore, by setting the predetermined gear ratio c to any value from 1 to the minimum gear ratio, the gear ratio region where the belt clamping pressure adjusting mechanism can be diagnosed is divided. As a result, the belt clamping pressure adjusting mechanism can be diagnosed with high accuracy.

  (C). The normal determination is made when the deviation DWDLPR> f, the input torque TT to the primary sheave 2a ≧ the reference torque g, and the input shaft rotation speed NIN (primary sheave rotation speed) ≧ the reference rotation speed n continue for a predetermined time ty. (S108).

  The presence of the conditions of the input torque TT and the input shaft rotational speed NIN makes it clear that the upshift is being performed during acceleration, and the belt clamping pressure adjusting mechanism can be diagnosed with higher accuracy.

  (D). As the precondition (S102), the condition that the input shaft rotational speed NIN ≧ the predetermined rotational speed a and the output shaft rotational speed NOUT ≧ the predetermined rotational speed b is added to RATIOT <c as a logical product condition. This makes it possible to make a diagnosis using a rotation speed range without error in detecting the speed ratio γ. Therefore, the diagnosis of the belt clamping pressure adjusting mechanism can be made with higher accuracy.

[Other embodiments]
(A). In the above embodiment, the example of the predetermined gear ratio c is set to 0.5, but as described in the first embodiment, it can be set to any value from 1 to the minimum gear ratio γmin. For example, c = 1 may be set. Also, c = minimum transmission ratio γmin may be set.

(B). The actual sheave position is obtained from the actual gear ratio γ according to the relationship shown in FIG. 5, but may be directly measured and used by providing a sheave position sensor directly.
Further, although the deviation DWDLPR between the target sheave position and the actual sheave position is determined, the deviation between the actual speed ratio γ and the target speed ratio RATIOT may be used instead for the determination.

  2 ... CVT, 2a ... primary sheave, 2b ... secondary sheave, 2c ... transmission belt, 2d, 2e ... hydraulic cylinder, 4 ... engine (internal combustion engine), 4a ... fuel injection valve, 6 ... torque converter, 8 ... forward / reverse switching , 10 ... reduction gear, 12 ... differential gear device, 14L, 14R ... left and right drive wheels, 16 ... input shaft, 18 ... output shaft, 20 ... hydraulic control circuit, 22 ... ECU, 22a ... engine ECU, 22b ... CVT-ECU, 24 ... shift lever, 26 ... operating position detection sensor, 28 ... throttle actuator, 30 ... throttle valve, 32 ... throttle sensor, 34 ... accelerator pedal, 36 ... accelerator operation amount sensor, 38 ... engine speed sensor, 40: Vehicle speed sensor (output shaft speed sensor), 42: Input shaft speed sensor, 52: Line pressure valve, 54: Up Shift valve, 56 ... belt clamping pressure valve, 58 ... Dautoshifuto valve, DS1, DS2 ... DUTY solenoid, P ... oil pump.

Claims (11)

By belting the primary sheave to which the driving force is input and the secondary sheave output to the drive system, the groove width between the primary sheave and the secondary sheave is adjusted through shift control of the actual gear ratio according to the target gear ratio. A diagnostic device for a belt clamping pressure adjustment mechanism in a continuously variable transmission that continuously changes output,
As a precondition, it is determined whether or not the target speed ratio calculated in the speed change control is in a region on the side smaller than the speed ratio range that can be reached when the belt clamping pressure adjusting mechanism is out of order. Precondition determining means;
When it is determined by the precondition determining means that the precondition is satisfied, the belt clamping pressure adjusting mechanism is diagnosed based on the relationship between the actual speed ratio and the target speed ratio when the speed ratio is reduced by the speed change control. Diagnostic means;
A belt clamping pressure adjusting mechanism diagnostic apparatus comprising: 2. The diagnostic device according to claim 1, wherein when the precondition determining unit determines that the precondition is satisfied, the diagnosis unit brings the actual gear ratio at the time when the gear ratio is reduced by the gearshift control closer to a target gear ratio. When this is difficult, the belt clamping pressure adjusting mechanism diagnostic device is characterized by determining a failure of the belt clamping pressure adjusting mechanism. 2. The diagnostic device according to claim 1, wherein when the precondition determining unit determines that the precondition is satisfied, the diagnosis unit brings the actual gear ratio at the time when the gear ratio is reduced by the gearshift control closer to a target gear ratio. And a belt clamping pressure adjusting mechanism diagnostic device, wherein the belt clamping pressure adjusting mechanism is judged to be normal when the belt clamping pressure adjusting mechanism is in a state in which it is possible. 2. The diagnostic device according to claim 1, wherein when the precondition determining unit determines that the precondition is satisfied, the diagnosis unit brings the actual gear ratio at the time when the gear ratio is reduced by the gearshift control closer to a target gear ratio. The belt clamping pressure adjusting mechanism is determined to be faulty when the condition is difficult, and the belt clamping pressure adjusting mechanism is determined to be normal when the actual gear ratio can be brought close to the target gear ratio. Diagnostic device for belt clamping pressure adjustment mechanism. 5. The normal determination according to claim 3, wherein the normal determination is a state in which the actual gear ratio can be brought close to the target gear ratio, the input torque of the primary sheave is larger than the reference torque, and the primary sheave rotational speed is the reference rotational speed. The belt clamping pressure adjusting mechanism diagnostic device is characterized in that the belt clamping pressure adjusting mechanism is diagnosed when a higher state continues for a predetermined time. 6. The diagnosis unit according to claim 3, wherein the diagnosis unit determines whether or not the actual speed ratio and the target speed ratio are within the proximity range, and determines whether the actual speed ratio and the target speed ratio are within the proximity range. A belt clamping pressure adjusting mechanism diagnosing device, characterized in that the gear ratio can be brought close to the target gear ratio. 5. The diagnostic device according to claim 2, wherein the diagnosis unit determines whether or not the actual speed ratio and the target speed ratio are within the separation range, and the state of being within the separation range continues for a predetermined time. A belt clamping pressure adjusting mechanism diagnostic device, characterized in that it is difficult to bring the running state close to the target gear ratio. The belt clamping pressure according to any one of claims 1 to 7, wherein the region where the target gear ratio is small is a region where the gear ratio is smaller than a value set in the range of 1 to the minimum gear ratio. Adjustment mechanism diagnostic device. In any one of Claims 1-7, the area | region where the said target gear ratio is small is the area | region which is the minimum gear ratio within the gear range of a continuously variable transmission, or this area | region and the vicinity of the minimum gear ratio. A belt clamping pressure adjusting mechanism diagnostic device characterized in that the region includes a belt. 10. The primary sheave rotational speed and the secondary sheave rotational speed according to claim 1, wherein the precondition determining unit is configured to precondition that the rotational speed of the primary sheave and the rotational speed of the secondary sheave with respect to a condition existing in a region where the target speed ratio is small. A belt clamping pressure adjusting mechanism diagnosing device, characterized in that a condition existing in a high region is added as a logical product condition. The mechanism for adjusting the groove width between the primary sheave and the secondary sheave according to any one of claims 1 to 10 is configured such that the volume of the hydraulic cylinder is increased by the inflow of the working liquid by the hydraulic cylinder. The groove width is reduced by enlarging and decreasing by the outflow of the working liquid, and the shift control is performed along with the belt clamping pressure control by the working hydraulic pressure on the hydraulic cylinders of the primary sheave and the secondary sheave, and the primary sheave liquid. A belt clamping pressure adjusting mechanism diagnosing device that executes a process of adjusting a transmission gear ratio according to a supply / discharge amount of hydraulic fluid to / from a pressure cylinder.

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