JP2003254431A - Slip detector for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for accurately determining a slip start time point and end time point of a continuously variable transmission. <P>SOLUTION: The slip detector for a continuously variable transmission, which detects a slip of a continuously variable transmission according to a correlation coefficient between an input rotating speed and an output rotating speed of the continuously variable transmission, comprises a slip timing determining means (Step S7, S11) for determining a time point other than a detection time point to be a slip start time point or end time point according as a slip is detected from the correlation coefficient. A time difference between the slip detection from the correlation coefficient and actual slip occurrence is thus corrected to offer an accurate determination of the slip start and end. The duration of the slip and a heat load in the duration is obtained accurately thereby. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting slippage of a continuously variable transmission which transmits torque by utilizing frictional force, shearing force of traction oil and the like.

[0002]

2. Description of the Related Art A transmission such as a belt type continuously variable transmission or a traction type (toroidal type) continuously variable transmission transmits torque without depending on meshing, so that the transmission torque (or torque capacity) is exceeded. Excessive slippage may occur due to the action of torque. If such excessive slippage occurs, the power transmission efficiency will decrease,
Alternatively, durability may be impaired, and particularly in a continuously variable transmission, wear of a transmission member such as a belt and a torque transmission surface may increase.

Conventionally, a device for detecting a failure of a continuously variable transmission before a problem occurs in traveling of a vehicle is disclosed in JP-A-62-2.
No. 059 publication. The invention described in this publication makes a failure determination when the gear ratio obtained from the input / output speed exceeds a maximum value or a minimum value, or when the speed of change of the gear ratio exceeds a set value. , Is configured to alert the user when the frequency becomes high.

[0004]

In the inventions described in the above publications, slippage in a continuously variable transmission can be detected. However, it is a slip as a result of a failure of the continuously variable transmission or a slip causing the failure, and therefore, the gear ratio exceeds one of the upper and lower limit values, or the gear change speed becomes excessive. Therefore, the failure is determined. Therefore, the conventional device cannot detect slippage of the belt or the like until the gear ratio and the gear shift speed reach such extreme values.

In the continuously variable transmission, if the clamping pressure for clamping the belt or the power roller that mediates the transmission of torque is high,
Although slippage is less likely to occur, on the other hand, power transmission efficiency is reduced. Therefore, it is desirable to set the clamping pressure as low as possible within the range where slippage does not occur, but if the torque that acts on the continuously variable transmission suddenly changes, the slippage accompanying it can be detected in advance or immediately. There is a need to. For that purpose, it is necessary to detect a slight change in behavior as slip, such as detecting a change from so-called micro-slip to macro-slip, but in the invention described in the above publication, attention is paid to such a technical problem. Not only that, but also temporary or subtle slippage that cannot be called a failure cannot be detected.

The present invention has been made in view of the above technical problem, and provides a slip detecting device capable of easily detecting slip in a continuously variable transmission and start or end of the slip. That is the purpose.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is based on the result of slip detection based on the correlation detection coefficient of the input / output speed of a continuously variable transmission. It is characterized in that it is configured to determine the end time. More specifically, claim 1
The invention of (1) is a slip detection device for a continuously variable transmission that detects slip of the continuously variable transmission based on a correlation coefficient between an input speed and an output speed of the continuously variable transmission, wherein the correlation coefficient The slip detecting device is characterized by further comprising a slip timing determining means for determining another time different from the detection time as the slip start time or the end time based on the detection of the slip.

Therefore, according to the first aspect of the present invention, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. The time different from the time when the slip is detected is determined as the start time or the end time of the slip.
Therefore, as soon as slippage occurs in the continuously variable transmission, that is, slippage is detected by a slight increase in slippage. Further, based on the fact that the slip is detected in this manner, the time when the slip starts or the time when the slip ends is accurately determined.

Further, the invention of claim 2 is configured such that the slip timing determining means in claim 1 determines a time point, which is a certain time before the slip determination time based on the correlation coefficient, as a slip start time. It is a slip detection device characterized by the above.

Therefore, according to the second aspect of the present invention, the correlation coefficient of the input / output speed is calculated, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. A time point before a certain time from the time point when the slip is detected is determined as the start time point of the slip. Therefore, slippage in the continuously variable transmission is quickly detected, and the start point of the slippage is accurately determined.

Further, in the invention of claim 3, the slip timing determining means in claim 1 determines the slip of the slip based on a gear ratio at a time point which is a predetermined time before the slip detection time by the correlation coefficient. The slip detecting device is characterized in that it is configured to determine a start time point or an end time point.

Therefore, according to the third aspect of the present invention, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. The start point of the slip or the end point of the slip is determined based on the gear ratio at the time when the slip is detected.
Therefore, as soon as slippage occurs in the continuously variable transmission, that is, slippage is detected by a slight increase in slippage. Further, based on the fact that the slip is detected in this manner, the time when the slip starts or the time when the slip ends is accurately determined.

Further, the invention of claim 4 is the same as claim 1
The slip timing determining means in the invention of claim 1 based on the speed change ratio at a predetermined time before the time when the slip is detected by the correlation coefficient and the change state of the speed change ratio before the time, the start time of the slip. Alternatively, the slip detection device is characterized in that it is configured to determine the end time.

Therefore, according to the invention of claim 4, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. The start point of the slip or the end point of the slip is determined based on the speed ratio at the time of detecting the slip and the state of the change in the speed ratio up to that point. Therefore, as soon as slippage occurs in the continuously variable transmission, that is, slippage is detected by a slight increase in slippage. Further, based on the fact that the slip is detected in this manner, the time when the slip starts or the time when the slip ends is accurately determined.

According to a fifth aspect of the invention, in any one of the first to fourth aspects of the invention, deterioration determining means for determining the degree of deterioration of the continuously variable transmission based on the fact that the correlation coefficient is obtained. It is a slip detecting device characterized by further comprising.

Therefore, according to the invention of claim 5, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. For example, the duration of the slip is known, and as a result, the degree of deterioration caused by the slip is determined.

The invention of claim 6 is the same as that of claim 3.
Alternatively, in the invention of the fourth aspect, the slip detecting device further comprises deterioration determining means for determining a degree of deterioration of the continuously variable transmission based on a start time point or an end time point of the slip.

Therefore, according to the sixth aspect of the present invention, when slip is detected based on the correlation coefficient of the input / output rotation speed, the start or end time of the slip is determined, and the start or end of the slip is determined. Based on this, the degree of deterioration of the continuously variable transmission is determined.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described based on specific examples. First, a drive mechanism including a continuously variable transmission which is a target of the present invention will be described. The present invention can be applied to a drive mechanism mounted on a vehicle, and the continuously variable transmission included in the drive mechanism is , A belt type continuously variable transmission that uses a belt as a torque transmission member, or a toroidal type (traction type) continuously variable transmission that uses a power roller as a torque transmission member and uses the shearing force of oil (traction oil) to transmit torque It is a transmission. FIG. 6 schematically shows an example of a vehicle drive mechanism including the belt-type continuously variable transmission 1. The continuously variable transmission 1 is driven by a forward / reverse switching mechanism 2 and a torque converter 3 to generate power. It is connected to the source 4.

The power source 4 is similar to the power source mounted on a general vehicle, and includes an internal combustion engine such as a gasoline engine, a diesel engine or a natural gas engine, an electric motor, or an internal combustion engine and an electric motor. It is possible to employ a mechanism or the like in which In the following description, the power source 4 will be referred to as the engine 4.

The torque converter 3 connected to the output shaft of the engine 4 has the same structure as the torque converter used in the conventional general vehicle, and the pump is attached to the front cover 5 to which the output shaft of the engine 4 is connected. The impeller 6 is integrated, and a turbine runner 7 facing the pump impeller 6 is arranged adjacent to the inner surface of the front cover 5. The pump impeller 6 and the turbine runner 7 are provided with a large number of blades (not shown). When the pump impeller 6 rotates, a spiral flow of fluid is generated and the spiral flow is generated. The turbine runner 7 is rotated by applying a torque to the turbine runner 7.

A stator 8 for selectively changing the flow direction of the fluid sent from the turbine runner 7 and allowing the fluid to flow into the pump impeller 6 is arranged at the inner peripheral sides of the pump impeller 6 and the turbine runner 7. Has been done. The stator 8 is connected to a predetermined fixed portion 10 via a one-way clutch 9.

The torque converter 3 has a lockup clutch 11. Lockup clutch 11
Are arranged in parallel to a substantial torque converter including a pump impeller 6, a turbine runner 7, and a stator 8, and are held by the turbine runner 7 in a state of facing the inner surface of the front cover 5. By being pressed against the inner surface of the front cover 5 by hydraulic pressure, torque is directly transmitted from the front cover 5 which is an input member to the turbine runner 7 which is an output member. The torque capacity of the lockup clutch 11 can be controlled by controlling the hydraulic pressure.

The forward / reverse switching mechanism 2 is a mechanism adopted because the rotation direction of the engine 4 is limited to one direction, and outputs the input torque as it is and outputs it by reversing it. Is configured to. In the example shown in FIG. 6, a double pinion type planetary gear mechanism is adopted as the forward / reverse switching mechanism 2.

That is, the ring gear 13 is arranged concentrically with the sun gear 12, and between the sun gear 12 and the ring gear 13, the pinion gear 14 meshed with the sun gear 12, the pinion gear 14 and the other pinion gear 15 meshed with the ring gear 13. And the pinion gears 14 and 15 are rotatably and revolvably held by the carrier 16. A forward clutch 17 that integrally connects the two rotating elements (specifically, the sun gear 12 and the carrier 16) is provided, and by selectively fixing the ring gear 13, the direction of the output torque is obtained. A reverse brake 18 for reversing is provided.

The continuously variable transmission 1 has the same structure as a conventionally known belt type continuously variable transmission, and each of a driving pulley 19 and a driven pulley 20 arranged in parallel with each other has a fixed sheave, Hydraulic actuators 21, 22
And a movable sheave that can be moved back and forth in the axial direction. Therefore, each pulley 19, 20
Groove width changes by moving the movable sheave in the axial direction, and the winding radius of the belt 23 wound around the pulleys 19 and 20 (effective diameter of the pulleys 19 and 20) continuously changes accordingly. However, the gear ratio changes continuously. The drive pulley 19 is connected to the carrier 16 which is an output element of the forward / reverse switching mechanism 2.

The hydraulic actuator 22 in the driven pulley 20 receives hydraulic pressure (line pressure or its correction pressure) corresponding to the torque input to the continuously variable transmission 1 via a hydraulic pump and hydraulic control device (not shown). Is being supplied. Therefore, when each sheave in the driven pulley 20 sandwiches the belt 23, a tension is applied to the belt 23 and a sandwiching pressure (contact pressure) between the pulleys 19 and 20 and the belt 15 is secured. .
In other words, the torque capacity according to the clamping force is set. On the other hand, the hydraulic actuator 21 in the drive pulley 19 is supplied with pressure oil according to the gear ratio to be set, and the groove width (effective diameter) is set according to the target gear ratio. .

A driven pulley 20 which is an output member of the continuously variable transmission 1 is connected to a gear pair 24 and a differential 25, and the differential 25 is connected to left and right drive wheels 26.

Various sensors are provided to detect the operating state (running state) of the vehicle in which the continuously variable transmission 1 and the engine 4 are mounted. That is, the engine 4
Rotation speed (input rotation speed of the lockup clutch 11) N
Engine speed sensor 2 that detects e and outputs a signal
7, a turbine rotation speed sensor 28 that detects the rotation speed of the turbine runner 7 (the output rotation speed of the lockup clutch 11) and outputs a signal, and the rotation speed Nin of the drive pulley 19
An input rotation speed sensor 29 for detecting the rotation speed and outputting a signal, an output rotation speed sensor 30 for detecting the rotation speed Nout of the driven pulley 20 and outputting a signal, and the like are provided.

Control of engagement / release of the forward clutch 17 and the reverse brake 18 and the belt 23
The electronic control unit (CVT) for the transmission for controlling the clamping force of the clutch, controlling the torque capacity including engagement / disengagement of the lockup clutch 11, and controlling the gear ratio.
-ECU) 31 is provided. This electronic control unit 3
1 is composed mainly of a microcomputer as an example, performs calculations according to a predetermined program based on input data and previously stored data, and various states such as forward and reverse or neutral, and required. It is configured to execute control such as setting of clamping pressure and setting of gear ratio. Further, an electronic control unit for an engine (E
-ECU) 32 is provided, and these electronic control units 3
Data is communicated between 1 and 32.

The device of the present invention intended for the continuously variable transmission 1 detects slippage in the continuously variable transmission 1, and
It is configured to determine the start time point or the end time point of the slip. This is to determine the damage caused by slippage, that is, the degree of deterioration. FIG. 1 shows an example of the control, and the routine shown by the flowchart in FIG. 1 is repeatedly executed at every predetermined short time t.

In FIG. 1, first, the input speed Nin (i) and the output speed Nout (i) of the continuously variable transmission 1 are measured, and the speed ratio γ (i) is measured using these measured values. Is calculated (step S1). In addition, these input / output speed Nin
(i) and Nout (i) are rotation speeds detected by the input rotation speed sensor 29 and the output rotation speed sensor 30, respectively.

Then, the correlation coefficient k (i) is calculated using the latest N input rotation speeds Nin and output rotation speeds Nout (step S2). The correlation coefficient k (i) is a coefficient obtained by the following equation, and the input rotation speed Nin
The relationship between (i) and the output speed Nout (i) is shown.

[Formula 1]

This correlation coefficient k (i) is the input speed Nin
If the ratio between (i) and the output speed Nout (i) matches the gear ratio at that time, it becomes "1", and if a so-called abnormality such as slippage of the belt 23 occurs, the value gradually decreases. . Therefore, it is determined whether or not excessive slippage (macroslip) that exceeds the slight slippage (microslip) inevitably generated in the continuously variable transmission 1 due to the transmission of torque has occurred (step S2). . Specifically, it is determined whether the above correlation coefficient k (i) is smaller than a predetermined determination reference value k_mslp_S1.

The judgment reference value k_mslp_S1 is a value close to "1", for example, a value of about "0.99".
If the correlation coefficient k (i) is greater than or equal to the determination reference value k_mslp_S1 and a negative determination is made in step S3, it means that the continuously variable transmission 1 does not slip.
Therefore, in this case, the counter Mslp_Cnt and the flag Coh_Flag (i), which will be described later, are cleared (step S4),
This routine ends.

On the other hand, if the determination in step S3 is affirmative, it means that the continuously variable transmission 1 is slipping. Therefore, the slip of the continuously variable transmission 1 is detected at this time. The flag Coh_Flag (i) is set to "1" because the determination that the slip has occurred in the continuously variable transmission 1 is set to "1" (step S5). Then, it is determined by the flag Coh_Flag (i) whether or not the continuously variable transmission 1 has changed from the state in which no slip has occurred to the state in which slip has occurred (step S6). That is, it is determined whether the flag Coh_Flag (i-1) is "0" immediately before and the flag Coh_Flag (i-1) is "1" at the present time. This is a judgment as to whether or not the flag Coh_Flag has been switched from "0" to "1" at the present moment.

When the determination in step S6 is affirmative, a predetermined control I for determining the slippage of the belt 23 is executed (step S7). An example of the predetermined control I is shown in FIG. First, a predetermined time (n) from the current time (i)
The gear ratio γ (in) at the previous time (in) is fixed as the gear ratio γ_stat (in) at the time when the slip of the belt 23 starts (step S71). That is, when slippage in the continuously variable transmission 1 is detected based on the correlation coefficient k (i), it is determined that the slippage has started a predetermined time (n) before that point, and the start point of the slippage is determined. Has been done.

Further, a predetermined time has passed since the start of this slip.
The change amount Δγ_stat of the gear ratio γ up to (m) is calculated (step S72). That is, the change amount of the gear ratio γ in the so-called stable state or steady state without slippage of the continuously variable transmission 1 is obtained. Then, the change amount Δγ_stat is used to determine the gear ratio γ_stat (i-n + j) at each point from the start point of the slip to the present point (step S7).
3). Specifically, the calculation described in step S73 of FIG. 2 is executed.

Then, the start of the slip of the belt 23 is determined, and the counting of the time by the counter Mslp_Cnt is started (step S74). In other words, belt 2
A time measurement is started to determine the duration of the 3 slide.

Then, the value of "j", which indicates the time point after the time point when the slip of the belt 23 is considered to have started, becomes the value "n" which corresponds to the time from the present time point to the start time of the belt slip. It is determined whether or not it has reached (step S7).
5). When a negative determination is made in step S75, each time it is incremented by "1" (step S75), the process returns to step S73. That is, the speed ratio at each time point from the start time (in) of the slip of the belt 23 to the current time point (n) is obtained.

After the above step S7 of executing the subroutine shown in FIG. 2, the gear ratio prediction flag γst_Flag (i) indicating that the continuously variable transmission 1 is slipping is "1".
Is set (step S8) and the process returns.

On the other hand, if the slippage of the belt 23 has already been determined, or if the slippage determination has not been established, a negative determination is made in step S6.
In that case, it is determined whether or not the gear ratio prediction flag γst_Flag (i) is set to "1" (step S9). The gear ratio prediction flag γst_Flag is set to "1" because the slip in the continuously variable transmission 1 is detected and the start time point of the slip is determined as described above. Therefore, the continuously variable transmission 1 If the slip has already been detected, step S8 has been executed in the previous cycle, and therefore a positive determination is made in step S9.

In this case, the gear ratio after the time when the slip is detected is estimated based on the correlation coefficient k (i), and it is determined based on the estimated value whether the slip continues or has ended. That is, first, the estimated gear ratio value γ_stat (i) is obtained (step S10). The calculation is the immediately preceding gear ratio estimated value γ_stat (i-1) obtained based on the gear ratio at the time when the start of slip is determined and the change state of the gear ratio (change amount of the gear ratio) before that. To the change amount Δ
This is done by adding γ_stat. The estimated gear ratio value γ_stat (i-1) and the amount of change Δγ_stat are values indicating the operating state at the time when it is determined as the time when the slip in the continuously variable transmission 1 is started, and the step S7 or FIG. It is obtained by the subroutine shown in.

The value obtained by subtracting the output speed Nout (i) from the value obtained by dividing the input speed Nin (i) by the estimated gear ratio γ_stat (i) or its absolute value is the macroslip judgment reference value. It is determined whether Mslp_rpm or more (step S11). Here, the value obtained by dividing the input speed Nin (i) by the gear ratio estimated value γ_stat (i) is the gear ratio estimated value γ_stat.
Since the value corresponds to the output rotation speed in the case of (i), the above difference or the absolute value thereof becomes smaller than the determination reference value Mslp_rpm if slippage does not occur.

Therefore, if the determination in step S11 is affirmative, the counter Mslp_Cnt is incremented (step S12). That is, the counting of the slip time is continued.

On the other hand, if the determination in step S11 is affirmative, the input speed Nin (i) and the output speed Nout (i)
This means that the difference in the number of revolutions between and has almost matched the value corresponding to the gear ratio. That is, it means that the slip has converged or ended and it has become a micro slip. Therefore, in this case, the gear ratio prediction flag γst_Flag (i) is reset to "0" (step S13). this is,
This is a control corresponding to the determination of the end of slippage. Then, a predetermined control II for calculating the belt damage is executed (step S14). An example of the control is shown in FIG.

Here, the belt damage is an example of calculation as the amount of heat due to slippage. First, the index 1 is reset to zero (step S141), and then the damage counter D is set.
_Cnt is incremented (step S142). Further, the slip time is calculated (step S143). As described above, the counter Mslp_Cnt continuously counts from the sliding start time to the sliding end time, and the value thereof corresponds to the number of times the routine shown in FIGS. 1 and 2 is repeated (that is, the number of times of sampling). Therefore, by multiplying the count value by the sampling period Sample_t, the time during which the slip has continued can be obtained.

Then, the damage of the belt 23 is calculated (step S144). This is the energy absorption rate ΔQ
It is calculated as (i) and the energy absorption amount that is the integrated value thereof. First, the energy absorption rate ΔQ (i) at each time point from the start of belt slip to the end of slip is calculated by the following equation.

[Formula 2]

Here, μ is the coefficient of friction between the belt 23 and the pulleys 19 and 20 in the continuously variable transmission 1, Rin is the winding radius of the belt 23 around the drive pulley 19, and
Ain is the pressure receiving area of the hydraulic actuator 21 on the drive pulley 19 side, Pd is the hydraulic pressure of the hydraulic actuator 22 on the driven pulley 20 side, v is a predetermined coefficient, and a is the belt 2
The included angle is 3.

The larger value of the energy absorption rate ΔQ thus obtained is selected.

[Formula 3]

Then, the energy absorption rate ΔQ is integrated to obtain the energy absorption amount Q.

[Formula 4]

After the above damage is calculated, it is determined whether the index 1 has reached the time count value Mslp_Cnt (step S145). This step S145
If the determination is negative, the index 1 is incremented (step S146), the process returns to step S144,
Continue calculating damage. That is, the amount of heat from the start to the end of slip is calculated.

Therefore, whenever slippage occurs in the continuously variable transmission 1, the amount of heat, that is, the damage due to the slippage is required each time. Therefore, it is possible to determine the replacement time of the belt 23 and to notify the replacement based on the damage.

When the slip of the continuously variable transmission 1 is completed in this way, or when the continuously variable transmission 1 has not slipped, a negative determination is made in step S9. In that case,
The gear ratio prediction flag γst_Flag (i) is reset to "0" (step S15), and the process returns.

When a slip occurs due to a change in the torque on the output side, an example of changes in the rotational speeds and the correlation coefficient and the timing of the slip start determination and the end determination can be shown by a time chart. 4 is as follows. Referring to FIG. 4, the output rotation speed Nout is lowered by the temporary increase in the output torque, and the input rotation speed Nin is accordingly reduced.
If slip occurs in the continuously variable transmission 1 in the process of lowering the output speed N, the output speed Nout further decreases with respect to the input speed Nin, so the correlation coefficient begins to decrease (time t1). Almost at the same time, the gear ratio γ temporarily increases. afterwards,
Since the correlation coefficient is smaller than the determination reference value k_mslp_S1, slippage in the continuously variable transmission 1 is detected (at time t2).

As described above, the slip determination time based on the correlation coefficient is delayed from the time when the actual slip of the belt 23 occurs.
Therefore, in the device according to the present invention, the time t1 which is a predetermined time (n) before the time of the slip detection based on the correlation coefficient
Is determined as the start time of the slip. After that,
Since the gear ratio γ increases due to slip, the gear ratio used for calculating the end of slip or damage is not the gear ratio at the time t2 when the slip is detected, but at the determined slip start time t1. The gear ratio γ_stat is used.

After that, the output torque is reduced, the output rotation speed Nout is restored, and the slippage is completed (time t3). Since the correlation coefficient obtained at that time includes the value of the output rotation speed Nout during the slippage, the correlation coefficient is smaller than the above-mentioned determination reference value k_mslp_S1. That is, the end of slip cannot be determined from the correlation coefficient. On the other hand, as described above, the difference between the value obtained by dividing the input rotational speed Nin by the gear ratio γ_stat and the output rotational speed Nout is smaller than the judgment reference value Mslp_rpm, so that the slippage is almost completed (at the time t3). The judgment is established.

Therefore, according to the device of the present invention,
The start of slippage in the continuously variable transmission 1 can be accurately detected or determined, and the end of slippage can be similarly accurately detected or determined. Therefore, since the time during which slippage has occurred can be accurately grasped, the heat load or damage of the continuously variable transmission 1 can be accurately detected.
Therefore. The present invention may be configured to notify the replacement time of the belt 23 or determine the replacement time based on the result of the damage detection.

By the way, in the above control example, the time point before the predetermined time (n) from the time point when the judgment of the slip of the belt 23 based on the correlation coefficient is established is judged as the slip start time point. Therefore, if the predetermined time (n) is excessive,
If the actual start of slipping is judged to be the start of slipping, or conversely, if the predetermined time (n) is too small, the start of slipping will be determined even if the slipping has started. Will be delayed. In order to reduce such a so-called error as much as possible, the control shown in FIG. 5 may be executed.

The flow chart shown in FIG. 5 is an alternative to the flow chart shown in FIG. 2, and the difference between the gear ratio estimated value γ_stat (i-n + j) and the measured value γ (i-n + j). It is the flowchart which inserted the step which evaluates to after step S73. That is, the difference between the measured value γ (i-n + j) and the estimated gear ratio value γ_stat (i-n + j) is the predetermined judgment reference value γ_slp.
It is determined whether _S or more (step S731).

The measured value γ (i-n + j) is the actual input speed N
Since it is obtained from in and the output rotation speed Nout, if slip occurs in the continuously variable transmission 1, the change in the rotation speed due to the slip is included. On the other hand, the estimated gear ratio γ
_stat (i-n + j) is the determined gear ratio at the start of slip and the change ratio of the gear ratio before that (gear ratio change rate)
It does not include the change in rotation due to slip because it was obtained based on Therefore, the difference between the two represents a change in the gear ratio associated with slippage or slippage in the continuously variable transmission 1.

Therefore, the difference is the predetermined judgment reference value γ_s.
Since it is equal to or greater than lp_S, if the determination in step S731 is affirmative, there is a change in the gear ratio at a time that is a predetermined time (n) before the time when the slippage is detected based on the correlation coefficient. The determination of belt slippage is established, and counting by the counter Mslp_Cnt is started (step S7).
4). On the other hand, if the determination in step S731 is negative, there is no change in the gear ratio, so the flow proceeds to step S75, and the determination of the start of slippage is not made.

If the control shown in FIG. 5 is executed as the predetermined control I in step S7 in the flow chart shown in FIG. 1, the determination of the slip start time becomes more accurate.
According to the control shown in FIG. 5, the determination result of step S731 can be used for determining the suitability of the predetermined time (n), and therefore the predetermined time (n) may be learned and corrected.

The relationship between the above-described specific example and the present invention will be briefly described below. Steps S7, S11,
Each functional means of S74 corresponds to the slip timing determining means of the present invention, and the functional means of step S144 corresponds to the deterioration detecting means of the present invention.

It should be noted that the present invention is not limited to the above specific examples, and can be applied to a slip detection device for a traction type continuously variable transmission other than the belt type continuously variable transmission. Further, each of the above judgment reference values and the predetermined value used for the judgment or the judgment may be a constant value set in advance, but a variable that changes based on the operating condition such as the acceleration / deceleration of the vehicle and the throttle opening. It may be (map value). Further, as for the degree of deterioration of the continuously variable transmission, other appropriate parameters may be used instead of the amount of heat.

[0066]

As described above, according to the first aspect of the invention, the correlation coefficient of the input / output rotation speed is obtained, and the slip in the continuously variable transmission is detected based on the correlation coefficient. Based on the detection of the slip, a time different from the time when the slip is detected is determined as the start time or the end time of the slip. The slip is detected by the increase of s, and as a result, it is possible to accurately determine the start time or the end time of the slip.

According to the second aspect of the present invention, the correlation coefficient of the input / output speed is calculated, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. Based on this, the time point that is a certain time before the time point when the slip is detected is determined as the start time of the slip, so the slip in the continuously variable transmission can be quickly detected, or the start time of the slip can be accurately determined. be able to.

Further, according to the third aspect of the present invention, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. Based on this, the start point of the slip or the end point of the slip is determined based on the gear ratio at the time when the slip is detected. Is detected, and as a result, it is possible to accurately determine the time when the slip starts or ends.

Further, according to the invention of claim 4, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. Based on this, the slip start point or the end point of the slip is determined based on the gear ratio at the time of detecting the slip and the state of the change in the gear ratio up to that time, so slip occurs in the continuously variable transmission. Immediately, i.e. a slight increase in the slip, the slip is detected, so that it is possible to accurately determine when the slip started or ended.

According to the fifth aspect of the present invention, the correlation coefficient of the input / output speed is obtained, the slip in the continuously variable transmission is detected based on the correlation coefficient, and the slip is detected. Based on this, it is possible to know, for example, the duration of the slip, and as a result, it is possible to accurately determine the degree of deterioration due to slip.

Further, according to the invention of claim 6, when the slip is detected based on the correlation coefficient of the input / output rotation speed,
Since the start time or the end time of the slip is determined,
The degree of deterioration of the continuously variable transmission can be accurately determined based on the time point at which the slippage starts or ends.

[Brief description of drawings]

FIG. 1 is a diagram showing a flowchart for explaining an example of control by a control device of the present invention.

FIG. 2 is a flow chart showing an example of a subroutine for determining the start of belt slippage and the control accompanying it.

FIG. 3 is a flowchart showing an example of a subroutine for determining the end of belt slippage and damage.

FIG. 4 is a time chart showing an example of a slip start determination time and a slip end determination time by the control shown in FIG.

FIG. 5 is a flowchart showing a subroutine that replaces FIG.

FIG. 6 is a diagram schematically showing a drive mechanism including a continuously variable transmission according to the present invention.

[Explanation of symbols]

1 ... Continuously variable transmission, 3 ... Torque converter, 4 ... Engine (power source), 11 ... Lockup clutch, 1
9 ... Drive pulley, 20 ... Followed pulley, 23 ... Belt, 26 ... Drive wheel, 31 ... Electronic control unit for transmission (CVT-ECU).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16H 63:06 F16H 63:06 (72) Inventor Kunihiro Iwatsuki 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Vehicle Incorporated (72) Inventor Kazumi Hoshiya 1 Toyota-cho, Toyota-shi, Aichi F-term inside Toyota Motor Corporation (reference) 3J552 MA07 MA09 MA12 MA26 NA01 NB01 PA51 PB09 VA32W VA37W VA74W VC01Z

Claims (6)

[Claims] 1. A slip detecting device for a continuously variable transmission, which detects a slip of the continuously variable transmission based on a correlation coefficient between an input speed and an output speed of the continuously variable transmission, wherein the phase relation is provided. The slip of the continuously variable transmission, which is provided with a slip timing determination means for determining another time different from the detection time as the slip start time or the end time based on the detection of the slip by the number. Detection device. 2. The slip timing determination means is configured to determine a time point, which is a predetermined time before the slip determination time based on the correlation coefficient, as a slip start time. Slip detection device for continuously variable transmission. 3. The slip timing determination means determines the start time point or the end time point of the slip on the basis of a gear ratio at a time point that is a predetermined time before the time point when the slippage is detected by the correlation coefficient. The slip detection device for a continuously variable transmission according to claim 1, wherein the slip detection device is configured. 4. The slip timing determination means is configured to determine the slip based on a gear ratio at a time point that is a predetermined time before a time point when the slip is detected by the correlation coefficient and a change state of the gear ratio before the time point. The slip detection device for the continuously variable transmission according to claim 1, wherein the slip detection device is configured to determine a start time point or an end time point. 5. The deterioration determining means for judging the degree of deterioration of the continuously variable transmission based on the fact that the correlation coefficient is obtained, according to any one of claims 1 to 4. A slip detecting device for a continuously variable transmission as described. 6. The apparatus according to claim 3, further comprising deterioration determining means for determining a degree of deterioration of the continuously variable transmission based on a start time point or an end time point of the slip. Slip detection device for gear transmission.