JP5745698B2 - Control device for belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a belt-type continuously variable transmission that performs belt slip control (BSC) for reducing an actual secondary hydraulic pressure so that a belt maintains a micro slip state with respect to a primary pulley and a secondary pulley.

  Conventionally, in a belt-type continuously variable transmission in which a primary pulley and a secondary pulley are spanned by a belt, the actual secondary hydraulic pressure and the actual gear ratio are intended by superimposing sine wave vibration on the command secondary hydraulic pressure and exciting the command secondary hydraulic pressure. Vibrate. And what calculates the phase difference of the vibration component of the extracted actual secondary hydraulic pressure, and the vibration component of an actual gear ratio, and detects a belt slip state by this phase difference is known (for example, refer patent document 1).

When the belt slip state detection method described in Patent Document 1 is introduced into a shift control system having a belt-type continuously variable transmission, primary hydraulic control and secondary hydraulic control are performed during belt slip control as follows. Those are known (for example, see Patent Document 2).
First, the secondary hydraulic pressure control during normal control determines the command secondary hydraulic pressure by feedback control based on the deviation between the target secondary hydraulic pressure to obtain the required belt thrust (= belt clamping force) and the actual secondary hydraulic pressure by the sensor signal. Yes.
On the other hand, the secondary hydraulic pressure control during the belt slip control is detected based on the phase difference between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio by exciting the secondary hydraulic pressure with a sinusoidal vibration command. Based on the belt slip state, the correction amount of the command secondary hydraulic pressure is determined so that the belt maintains the micro slip state with respect to both pulleys.
That is, during the belt slip control, the feedback control of the secondary hydraulic pressure is stopped, and the secondary hydraulic pressure (= belt clamping force) is reduced compared to the normal control.

  However, when the belt slip state detection method described in Patent Document 1 is introduced into a speed change control system in which the primary hydraulic pressure and the secondary hydraulic pressure are regulated by pressure regulating valves (pressure control valves or flow rate control valves), belt slip control is performed. If the travel region that permits this is expanded, the detection accuracy of the belt slip state may be lowered, and the belt slip control is not stabilized. Therefore, the travel region where the belt slip control is permitted is a limited region where the belt slip state detection accuracy is ensured and the belt slip control is stabilized. For example, as described in Patent Document 2, a torque change condition that the torque change is small, a speed change condition that the speed change is slow, and a speed change condition that the selected speed change ratio is on the high speed ratio side. And a stable traveling region where all of the above are established is a traveling region in which belt slip control is permitted.

  As a result, the travel section in which belt slip control is permitted is shortened among all travel sections, and the secondary hydraulic pressure is reduced compared to that during normal control, and the belt that suppresses the drive system friction torque while maintaining the minimum belt clamping force. It is not possible to achieve the effect of reducing fuel consumption and electricity consumption targeted by slip control.

WO 2009/007450 A2 (PCT / EP2008 / 059092) Japanese Patent No. 4527805

  The present invention has been made paying attention to the above problems, and provides a control device for a belt-type continuously variable transmission capable of achieving both stability of belt slip control and expansion of a permitted range of belt slip control. The purpose is to do.

In order to achieve the above object, in the present invention, a primary pulley that is input from a drive source, a secondary pulley that is output to a drive wheel, a belt that spans the primary pulley and the secondary pulley, and an actual primary to the primary pulley. It is premised on a control device for a belt-type continuously variable transmission that includes a first pressure regulating valve that regulates hydraulic pressure and a second pressure regulating valve that regulates actual secondary hydraulic pressure to the secondary pulley. The control device for the belt type continuously variable transmission includes a phase difference calculating means, an initial phase setting means, a belt slip state detecting means, and a belt slip control means.
When the belt slip control permission condition is satisfied, the phase difference calculating unit vibrates the secondary hydraulic pressure to the secondary pulley, and calculates the phase difference between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual speed ratio. calculate.
The initial phase setting means has an initial phase that is a difference between a hydraulic initial phase that is an amplitude starting point of a vibration component characteristic of an actual secondary hydraulic pressure and a gear ratio initial phase that is an amplitude starting point of the vibration component characteristic of an actual gear ratio. It sets based on the determination of the pressure regulation state of the actual primary oil pressure by the first pressure regulating valve.
The belt slip state detecting means detects the belt slip state by correcting the phase difference calculated by the phase difference calculating means with the initial phase set by the initial phase setting means.
The belt slip control means determines a command secondary hydraulic pressure so that the belt maintains a micro slip state with respect to both pulleys based on detection of the belt slip state by the belt slip state detection means, and sets the actual secondary hydraulic pressure to the first secondary hydraulic pressure. The pressure is regulated by the 2 pressure regulating valve.
Here, the vibration component characteristics in the time domain are, for example,
y (t) = Asin (ωt + θ)
In this case, the “initial phase” refers to the phase θ _{t = 0} at _{t = 0} . Note that (ωt + θ) is referred to as a phase.

Therefore, in the initial phase setting means, the initial phase that is the difference between the initial hydraulic pressure phase of the actual secondary hydraulic pressure and the actual transmission gear ratio is set based on the determination of the regulated state of the actual primary hydraulic pressure by the first pressure regulating valve. The
In other words, it has been clarified that the initial phase of the gear ratio frequency characteristic factor, which is a part of the equation for calculating the slip state during belt slip control, is one of the causes for reducing the detection accuracy of the belt slip state.
The phase of the speed ratio frequency characteristic factor varies depending on the pressure regulation response of the first pressure regulating valve. This is because vibration due to the actual secondary hydraulic pressure vibration causes a thrust change to the primary pulley side via the belt. That is, since the response of the first pressure regulating valve is different, the primary pulley responds with a flow rate change between the primary pulley side actuator and the first pressure regulating valve. This response causes a phase shift of the gear ratio frequency characteristic factor.
Therefore, in the belt slip state detection means, the phase difference calculated including the initial phase is corrected by the initial phase set based on the determination of the pressure adjustment state of the actual primary hydraulic pressure, so that the phase difference after correction is This is the slip phase difference caused by the belt slip after eliminating the initial phase due to the primary oil pressure regulation state.
For this reason, the belt slip state is accurately detected regardless of the regulation state (= gear ratio state) of the primary hydraulic pressure, so that the belt slip control is stabilized and the speed ratio range condition permitting the belt slip control is relaxed. Thus, the permitted area for belt slip control is expanded.

  As in the present invention, since the initial phase, which is one of the causes of reducing the detection accuracy of the belt slip state, is obtained accurately based on the determination of the actual primary hydraulic pressure adjustment state, the belt slip control is stabilized. And the expansion of the permitted area for belt slip control can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing a drive system and a control system of a vehicle equipped with a belt type continuously variable transmission to which a control device of Example 1 is applied. 1 is a perspective view showing a belt-type continuously variable transmission mechanism provided in a drive system of a vehicle to which a control device of Embodiment 1 is applied. 1 is a perspective view showing a part of a belt constituting a belt-type continuously variable transmission mechanism provided in a drive system of a vehicle to which a control device of Example 1 is applied. It is a control block diagram which shows the algorithm of the belt slip control in the control apparatus of Example 1. FIG. It is a flowchart which shows the flow of the switching process between the normal control of the secondary hydraulic pressure performed by the CVT control unit 8 of Example 1, and belt slip control (BSC). 6 is a flowchart showing a secondary oil pressure excitation / correction process in the belt slip control in the switching process executed by the CVT control unit 8 according to the first embodiment. 7 is a flowchart illustrating an initial phase setting process in the belt slip control in the switching process executed by the CVT control unit 8 according to the first embodiment. BSC operation flag, SEC pressure F / B prohibition flag, accelerator opening, vehicle speed, engine torque, Ratio, SEC oil pressure, SEC_SOL current correction amount in the driving scene where normal control passes belt slip control / return control and returns to normal control -It is a time chart which shows each characteristic of the phase difference of SEC pressure vibration and Ratio vibration. It is a gear ratio characteristic figure which shows the permission area | region for every mode state in the belt slip control in Example 1 (each state on the transmission line by the hydraulic system in a pressure control valve). FIG. 6 is a block diagram illustrating a permission region for each mode state in belt slip control in the first embodiment. It is an image figure which shows the relationship between the initial phase and slip detection point in each mode state in the belt slip control in Example 1 (The relationship between the initial phase and slip detection point in each state [A]-[C]. (image)).

  Hereinafter, the best mode for realizing a control device for a belt type continuously variable transmission according to the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
The configuration of the control device for the belt-type continuously variable transmission CVT in the first embodiment includes “overall system configuration”, “belt slip control configuration”, “switching configuration between normal control and belt slip control”, “secondary during belt slip control” The description will be divided into “hydraulic control configuration” and “initial phase setting configuration during belt slip control”.

[Overall system configuration]
FIG. 1 is an overall system diagram showing a drive system and a control system of a vehicle equipped with a belt type continuously variable transmission to which the control device of the first embodiment is applied. FIG. 2 is a perspective view showing a belt type continuously variable transmission mechanism. FIG. 3 is a perspective view showing a part of the belt of the belt type continuously variable transmission mechanism. The overall system configuration will be described below with reference to FIGS.

As shown in FIG. 1, the drive system of a vehicle equipped with a belt-type continuously variable transmission to which the control device of the first embodiment is applied includes an engine 1, a torque converter 2, a forward / reverse switching mechanism 3, and a belt-type continuously variable transmission. A transmission mechanism 4, a final reduction mechanism 5, and drive wheels 6 and 6 are provided. The belt type continuously variable transmission CVT is configured by housing the torque converter 2, the forward / reverse switching mechanism 3, the belt type continuously variable transmission mechanism 4, and the final reduction mechanism 5 in a transmission case.

  As shown in FIG. 1, the engine 1 can control the output torque by an engine control signal from the outside, in addition to the control of the output torque by the accelerator operation by the driver. The engine 1 includes an output torque control actuator 10 that performs output torque control by a throttle valve opening / closing operation, a fuel cut operation, and the like.

  As shown in FIG. 1, the torque converter 2 is a starting element having a torque increasing function, and when the torque increasing function is not required, the engine output shaft 11 (= torque converter input shaft) and the torque converter output shaft 21 are connected. It has a lockup clutch 20 that can be directly connected. The torque converter 2 is provided with a turbine runner 23 connected to the engine output shaft 11 via a converter housing 22, a pump impeller 24 connected to the torque converter output shaft 21, and a case via a one-way clutch 25. The stator 26 is a component.

  As shown in FIG. 1, the forward / reverse switching mechanism 3 is a mechanism that switches an input rotation direction to the belt type continuously variable transmission mechanism 4 between a forward rotation direction during forward travel and a reverse rotation direction during reverse travel. The forward / reverse switching mechanism 3 includes a double pinion planetary gear 30, a forward clutch 31, and a reverse brake 32.

  As shown in FIG. 1, the belt-type continuously variable transmission mechanism 4 has no gear ratio that is the ratio of the input rotational speed of the transmission input shaft 40 and the output rotational speed of the transmission output shaft 41 due to a change in belt contact diameter. A continuously variable transmission function that changes in stages is provided, and includes a primary pulley 42, a secondary pulley 43, and a belt 44. As shown in FIG. 2, the primary pulley 42 includes a fixed pulley 42 a and a slide pulley 42 b, and the slide pulley 42 b is slid by the primary hydraulic pressure guided to the primary hydraulic chamber 45. As shown in FIG. 2, the secondary pulley 43 includes a fixed pulley 43 a and a slide pulley 43 b, and the slide pulley 43 b is slid by the primary hydraulic pressure guided to the secondary hydraulic chamber 46. As shown in FIG. 2, the belt 44 is stretched over sheave surfaces 42 c and 42 d forming a V shape of the primary pulley 42 and sheave surfaces 43 c and 43 d forming a V shape of the secondary pulley 43. As shown in FIG. 3, the belt 44 is formed by two sets of stacked rings 44a and 44a in which a large number of annular rings are stacked from the inside to the outside and a punched plate material, and is sandwiched between the two sets of stacked rings 44a and 44a. It is constituted by a large number of elements 44b that are connected to each other and provided in an annular shape. The element 44b has sheave surfaces 42c and 42d of the primary pulley 42 and flank surfaces 44c and 44c that contact the sheave surfaces 43c and 43d of the secondary pulley 43 at both side positions.

  As shown in FIG. 1, the final reduction mechanism 5 decelerates the transmission output rotation from the transmission output shaft 41 of the belt-type continuously variable transmission mechanism 4 and provides a differential function to the left and right drive wheels 6, 6. It is a mechanism to transmit to. The final reduction mechanism 5 is interposed in the transmission output shaft 41, the idler shaft 50, and the left and right drive shafts 51, 51, and has a first gear 52, a second gear 53, a third gear 54 having a reduction function. And a fourth gear 55 and a gear differential gear 56 having a differential function.

  As shown in FIG. 1, the control system of the vehicle equipped with a belt type continuously variable transmission to which the control device of the first embodiment is applied includes a transmission hydraulic pressure control unit 7 and a CVT control unit 8.

  The transmission hydraulic pressure control unit 7 is a hydraulic pressure control unit using a dual pressure control system that generates a primary hydraulic pressure Ppri guided to the primary hydraulic chamber 45 and a secondary hydraulic pressure Psec guided to the secondary hydraulic chamber 46. The transmission hydraulic pressure control unit 7 includes an oil pump 70, a regulator valve 71, a line pressure solenoid 72, a line pressure oil passage 73, a first pressure regulating valve 74, a primary hydraulic solenoid 75, and a primary pressure oil passage 76. , A second pressure regulating valve 77, a secondary hydraulic solenoid 78, and a secondary pressure oil passage 79 are provided.

  The regulator valve 71 is a valve that regulates the line pressure PL using the discharge pressure from the oil pump 70 as a base pressure. This regulator valve 71 has a line pressure solenoid 72 and adjusts the pressure of the oil pumped from the oil pump 70 to a predetermined line pressure PL in accordance with a command from the CVT control unit 8.

  The first pressure regulating valve 74 is a valve that uses the line pressure PL generated by the regulator valve 71 as a source pressure to generate a primary hydraulic pressure Ppri guided to the primary hydraulic chamber 45. The first pressure regulating valve 74 has a primary hydraulic solenoid 75 and applies an operation signal pressure to the spool of the first pressure regulating valve 74 in accordance with a command from the CVT control unit 8. The first pressure regulating valve 74 is brought into a valve pressure regulating state on the low gear ratio side, and guides the speed change pressure obtained by adjusting the line pressure PL from the line pressure oil path 73 by the pressure reduction control to the primary pressure oil path 76. The first pressure regulating valve 74 is fully opened on the high gear ratio side, and guides the line pressure PL from the line pressure oil passage 73 to the primary pressure oil passage 76 as it is. When the first pressure regulating valve 74 is mechanically fixed at the highest gear ratio, the slide pulley 43b of the secondary pulley 43 or the slide pulley 42b of the primary pulley 42 cannot stroke, and the first pressure regulating valve 74 is regulated. Since there is no pressure state, there is no influence on the pressure control, and no response delay occurs. The same applies to the shift response in the flow rate control. Therefore, they are in phase.

  The second pressure regulating valve 77 is a valve that uses the line pressure PL generated by the regulator valve 71 as a source pressure to generate a secondary hydraulic pressure Psec guided to the secondary hydraulic chamber 46. The second pressure regulating valve 77 has a secondary hydraulic solenoid 78 and applies an operation signal pressure to the spool of the second pressure regulating valve 77 in accordance with a command from the CVT control unit 8. Then, the second pressure regulating valve 77 is fully opened on the low gear ratio side, and guides the line pressure PL from the line pressure oil passage 73 to the secondary pressure oil passage 79 as it is. The second pressure regulating valve 77 is in a valve pressure regulating state on the high gear ratio side, and guides the gear shifting pressure obtained by regulating the line pressure PL from the line pressure oil passage 73 by the pressure reduction control to the secondary pressure oil passage 79.

  The CVT control unit 8 outputs a control command for obtaining a target line pressure corresponding to the throttle opening etc. to the line pressure solenoid 72, and a control command for obtaining a target gear ratio according to the vehicle speed, the throttle opening etc. Shift hydraulic control output to primary hydraulic solenoid 75 and secondary hydraulic solenoid 78, forward / reverse switching control for controlling engagement / release of forward clutch 31 and reverse brake 32, lockup control for controlling engagement / release of lockup clutch 20, Etc. The CVT control unit 8 includes a primary rotation sensor 80, a secondary rotation sensor 81, a secondary oil pressure sensor 82, an oil temperature sensor 83, an inhibitor switch 84, a brake switch 85, an accelerator opening sensor 86, a primary oil pressure sensor 87, and a line pressure sensor. Sensor information and switch information from 89, etc. are input. Further, torque information is input from the engine control unit 88 and a torque request is output to the engine control unit 88.

[Belt slip control configuration]
FIG. 4 is a control block diagram illustrating an algorithm of belt slip control in the control device of the first embodiment. Hereinafter, a belt slip control configuration will be described with reference to FIG.

  As shown in FIG. 4, the algorithm configuration of the belt slip control of the first embodiment includes a sine wave excitation command unit 91, an actual secondary hydraulic pressure detection unit 92, an actual transmission ratio detection unit 93, a bandpass filter 94, A band-pass filter 95 and a phase difference calculation unit 96 (phase difference calculation means) are provided. In addition, a first pressure regulating valve pressure regulation state determination unit 97, an initial phase setting unit 98 (initial phase setting unit), a slip phase difference determination unit 99, and a belt slip state detection unit 100 (belt slip state detection unit) Secondary hydraulic pressure correction amount determination unit 101 (belt slip control means).

  The sine wave excitation command unit 91 determines an excitation frequency and an excitation amplitude suitable for belt slip control, and applies them to the command secondary hydraulic pressure so as to apply a sine wave hydraulic vibration with the determined frequency and amplitude to the secondary hydraulic pressure. Outputs sine wave excitation command.

  The actual secondary hydraulic pressure detection unit 92 detects the secondary hydraulic pressure that is hydraulically oscillated by a sine wave excitation command applied to the command secondary hydraulic pressure, by using the secondary hydraulic pressure sensor 82.

  The actual gear ratio detection unit 93 calculates the ratio (= actual gear ratio) of the primary rotation speed from the primary rotation sensor 80 and the secondary rotation speed from the secondary rotation sensor 81 to obtain the secondary hydraulic pressure that is hydraulically oscillated. Based on this, the actual transmission gear ratio is detected.

  The bandpass filter 94 is a filter that passes hydraulic vibration data in the excitation frequency band, and extracts the vibration component of the secondary hydraulic pressure from the detection data acquired by the actual secondary hydraulic pressure detection unit 92.

  The band-pass filter 95 is a filter that allows passage of vibration ratio vibration data in the excitation frequency band, and extracts vibration components of the actual gear ratio from the detection data acquired by the actual gear ratio detection unit 93.

  The phase difference calculation unit 96 calculates the phase difference between the vibration component of the secondary hydraulic pressure extracted by the band pass filter 94 and the vibration component of the actual gear ratio extracted by the band pass filter 95.

The first pressure regulation valve pressure regulation state determination unit 97 in the hydraulic system of the pressure control valve determines whether the first pressure regulation valve 74 is fully open (state B) based on sensor signals from the primary hydraulic pressure sensor 87 and the line pressure sensor 89. Then, it is determined whether the first pressure regulating valve 74 is in the pressure regulation state (state C). In the mechanical high state (state A), the first pressure regulation valve pressure regulation state determination unit 97 does not perform the determination.
Note that the first pressure regulating valve pressure regulation state determination unit 97 in the hydraulic system in the flow control valve is configured so that the first pressure regulating valve 74 is in a fully closed state (state) based on sensor signals from the primary hydraulic pressure sensor 87 and the line pressure sensor 89. D) or whether the first pressure regulating valve 74 is in a pressure regulation state (state E). In the mechanical high state (state A), the first pressure regulation valve pressure regulation state determination unit 97 does not perform the determination.

  The initial phase setting unit 98 is based on the determination result by the first pressure regulating valve pressure regulation state determination unit 97, the initial phase = 0 ° for the states A and D, the initial phase = 90 ° for the state B, and the state C. If so, the initial phase is set to 90 ° to 180 °.

  The slip phase difference determination unit 99 replaces the phase difference calculated by the phase difference calculation unit 96 with the initial phase set by the initial phase setting unit 98, and determines the slip phase difference based on the belt slip.

  The belt slip state detection unit 100 detects a belt slip state based on the slip phase difference from the slip phase difference determination unit 99. At this time, the slip phase difference may be detected as it is as a belt slip state. Further, the slip phase difference may be converted into a belt slip ratio or the like using a map or the like, and the converted belt slip ratio or the like may be detected as a belt slip state.

  The secondary hydraulic pressure correction amount determination unit 101 determines a secondary hydraulic pressure correction amount based on the belt slip state detected by the belt slip state detection unit 100, and uses the determined secondary hydraulic pressure correction amount as a command secondary hydraulic pressure or sine wave excitation command. Add to. Here, the secondary hydraulic pressure correction amount is determined as any one of the subtraction correction amount, the maintenance correction amount, and the addition correction amount so that the belt slip state maintains the micro slip state during the belt slip control.

[Switching configuration between normal control and belt slip control]
FIG. 5 is a flowchart showing a switching process between the normal control of the secondary hydraulic pressure and the belt slip control (= “BSC”) executed by the CVT control unit 8 according to the first embodiment. Hereinafter, each step of FIG. 5 will be described.

  In step S1, normal control of the belt-type continuously variable transmission mechanism 4 is performed following start by key-on, determination of BSC disapproval in step S2, or normal control return processing in step S5, and the process proceeds to step S2. . During normal control, the BSC operation flag = 0 is set and the secondary pressure F / B prohibition flag is set to zero.

In step S2, following the normal control in step S1, it is determined whether or not all the following BSC permission conditions are satisfied. If YES (all BSC permission conditions are satisfied), the process proceeds to step S3 to perform belt slip control (BSC). If NO (there is a condition that does not satisfy even one of the BSC permission conditions), the process returns to step S1 to continue normal control.
Here, an example of the BSC permission condition is shown below.
(1) The transmission torque capacity of the belt type continuously variable transmission mechanism 4 is stable (the rate of change of the transmission torque capacity is small).
This condition (1) is, for example,
a. | Command torque change rate | <predetermined value
b. Judgment based on two conditions: | command speed ratio change rate | <predetermined value.
(2) The estimation accuracy of the input torque to the primary pulley 42 is within a reliable range.
The condition (2) is determined based on, for example, torque information (estimated engine torque) from the engine control unit 88, the lock-up state of the torque converter 2, the operation state of the brake pedal, the range position, and the like.
(3) Continue the permission states (1) and (2) above for a predetermined time.
In step S2, it is determined whether or not all of the above conditions (1), (2), and (3) are satisfied.

  In step S3, following the BSC permission determination in step S2 or the BSC continuation determination in step S4, the input to the belt 44 of the belt type continuously variable transmission mechanism 4 is reduced, and the belt 44 is not slipped. Belt slip control (FIGS. 6 and 7) for maintaining a smooth slip state (micro slip state) is performed, and the process proceeds to step S4. During the belt slip control, the BSC operation flag = 1 is set and the secondary pressure F / B prohibition flag is set to “1”.

  In step S3, during belt slip control, as belt slip control processing, feedback control prohibition processing (step S31) for obtaining an instruction secondary hydraulic pressure using actual secondary hydraulic pressure, and torque limit processing (step S31) in preparation for returning to normal control. Step S32), excitation / correction processing of the secondary hydraulic pressure for performing belt slip control (Step S33: FIG. 6), and detection accuracy of the belt slip state regardless of the pressure regulation state of the first pressure regulating valve 74 are ensured. The initial phase setting process (step S34: FIG. 7) is performed simultaneously.

In step S4, following the belt slip control in step S3, it is determined whether or not all the following BSC continuation conditions are satisfied. If YES (all BSC continuation conditions are met), the process returns to step S3 and belt slip control (BSC) is continued as it is. If NO (there is a condition that does not satisfy even one of the BSC continuation conditions), the process proceeds to step S5, and normal control return processing is performed.
Here, an example of the BSC continuation condition is shown below.
(1) The transmission torque capacity of the belt type continuously variable transmission mechanism 4 is stable (the rate of change of the transmission torque capacity is small).
This condition (1) is, for example,
a. | Command torque change rate | <predetermined value
b. Judgment based on two conditions: | command speed ratio change rate | <predetermined value.
(2) The estimation accuracy of the input torque to the primary pulley 42 is within a reliable range.
The condition (2) is determined based on, for example, torque information (estimated engine torque) from the engine control unit 88, the lock-up state of the torque converter 2, the operation state of the brake pedal, the range position, and the like.
It is determined whether or not both of the above conditions (1) and (2) are satisfied. That is, the difference between the BSC permission condition and the BSC continuation condition is that the BSC continuation condition does not have the continuation condition (3) among the BSC permission conditions.

  In step S5, following the determination that any one of the BSC continuation conditions in step S4 is not satisfied, normal control return processing for preventing the belt 44 from slipping when returning from belt slip control to normal control is performed. After completion of the process, the process returns to step S1 and shifts to normal control.

  In this step S5, during the return from the belt slip control to the normal control until the normal control is started after the BSC continuation is stopped, the normal control return process is the feedback control return process for obtaining the command secondary hydraulic pressure using the actual secondary hydraulic pressure. (Step S51), torque limit processing (step S52) toward return to normal control, secondary oil pressure excitation / correction reset processing (step S53) for belt slip control, and shift for regulating the shift speed The restriction process (step S54) is performed simultaneously.

[Secondary hydraulic control configuration during belt slip control]
FIG. 6 is a flowchart illustrating the secondary hydraulic pressure excitation / correction process (step S33) in the belt slip control (BSC) in the switching process executed by the CVT control unit 8 according to the first embodiment. Hereinafter, each step of FIG. 6 showing the secondary hydraulic pressure control configuration during belt slip control will be described.

  In step S331, the command secondary hydraulic pressure is vibrated. That is, a sine wave hydraulic pressure with a predetermined amplitude and a predetermined frequency is superimposed on the command secondary hydraulic pressure, and the process proceeds to step S332.

  In step S332, following the excitation of the command secondary hydraulic pressure in step S331, the actual secondary hydraulic pressure is detected from the secondary hydraulic sensor 82, and the actual gear ratio is determined based on the rotational speed information from the primary rotation sensor 80 and the secondary rotation sensor 81. It detects by calculation and progresses to step S333.

In step S333, following the detection of the actual secondary hydraulic pressure and the actual gear ratio in step S332, bandpass filter processing is performed on each of the actual secondary hydraulic pressure and the actual gear ratio, and vibration components (sine Wave) is multiplied and multiplied, and the multiplication value is subjected to low-pass filter processing to obtain a value represented by the amplitude and the phase difference θ (cosine wave) from the actual secondary hydraulic vibration to the actual gear ratio vibration. Convert to step S334.
Here, assuming that the actual secondary hydraulic pressure amplitude is A and the actual gear ratio amplitude is B,
Actual secondary hydraulic vibration: Asinωt (1)
Actual gear ratio vibration: Bsin (ωt + θ) (2)
It is represented by
Multiplying (1) and (2) is the sum of products formula
sinαsinβ = -1 / 2 {cos (α + β) -cos (α-β)} (3)
Using
Asinωt × Bsin (ωt + θ) = (1/2) ABcosθ− (1/2) ABcos (2ωt + θ) (4)
It becomes.
In the above equation (4), when the low-pass filter is passed, (1/2) ABcos (2ωt + θ), which is a component twice the excitation frequency, is reduced.
Asinωt × Bsin (ωt + θ) ≒ (1/2) ABcosθ (5)
Thus, the amplitudes A and B and the phase difference θ from the actual secondary hydraulic vibration to the actual gear ratio vibration can be expressed.

  In step S334, following the calculation of the phase difference θ from the actual secondary hydraulic vibration to the actual gear ratio vibration in step S333, the initial phase set by the initial phase setting process shown in FIG. 7 is read, and the process proceeds to step S335.

  In step S335, following the reading of the initial phase in step S334, the slip phase difference Sθ generated by the belt slip is calculated from the initial phase and the calculated phase difference θ, and the process proceeds to step S336.

  In step S336, following the calculation of the slip phase difference Sθ in step S335, it is determined whether or not the slip phase difference Sθ is 0 ≦ Sθ <predetermined value 1 (a value indicating a micro slip region). If YES (0 ≦ Sθ <predetermined value 1), the process proceeds to step S337. If NO (predetermined value 1 ≦ Sθ), the process proceeds to step S338.

  In step S337, following the determination in step S336 that 0 ≦ Sθ <predetermined value 1, that is, no belt slip has occurred until reaching the micro slip region, the secondary hydraulic pressure correction amount is set to “−ΔPsec (decrease)”. And go to step S341.

  In step S338, following the determination in step S336 that the predetermined value 1 ≦ Sθ, that is, the belt slip exceeding the micro slip region has occurred, the slip phase difference Sθ is 0 ≦ Sθ <predetermined value 2 (target slip region ) Or not. If YES (predetermined value 1 ≦ Sθ <predetermined value 2), the process proceeds to step S339. If NO (predetermined value 2 ≦ Sθ), the process proceeds to step S340.

  In step S339, following the determination that the predetermined value 1 ≦ Sθ <predetermined value 2 in step S338, that is, an appropriate belt slip state that is greater than or equal to the micro slip region but less than the target slip region, “0 (maintain)” is set, and the process proceeds to step S341.

  In step S340, following the determination that the predetermined value 2 ≦ Sθ (micro / macro slip transition region) in step S338, the secondary hydraulic pressure correction amount is set to “+ ΔPsec (increase)”, and the process proceeds to step S341.

  In step S341, following the setting of the secondary hydraulic pressure correction amount in steps S337, S339, and S340, the basic secondary hydraulic pressure + secondary hydraulic pressure correction amount is set as the command secondary hydraulic pressure, and the process proceeds to the end.

[Initial phase setting configuration during belt slip control]
FIG. 7 is a flowchart showing the initial phase setting process (step S34) in the belt slip control (BSC) in the switching process executed by the CVT control unit 8 of the first embodiment. Hereinafter, each step representing the initial phase setting configuration during belt slip control will be described.

  In step S350, it is determined whether or not the mechanical high state (state A) is set. If YES (mechanical high state), the process proceeds from step S363 (state A) to step S364. In step S364, the initial phase α is set to 0 ° and the process proceeds to the end. If NO (a state other than mechanical high), the process proceeds to step S351. In step S351, sensor signals from the primary hydraulic sensor 87 and the line pressure sensor 89 are read, and the process proceeds to step S352.

  In step S352, following the reading of the sensor signal in step S351, it is determined whether or not the primary pressure control by the first pressure regulating valve 74 is pressure control. If YES (pressure control), the process proceeds to step S353, and if NO (flow rate control), the process proceeds to step S358.

  In step S353, following the determination that the primary pressure control in step S352 is pressure control, it is determined whether or not line pressure = primary pressure. If YES (line pressure = primary pressure), the process proceeds from step S354 (state B) to step S355. In step S355, the initial phase β is set to 90 ° and the process proceeds to the end.

  If NO (line pressure ≠ primary pressure) in step S353, the process proceeds from step S356 (state C) to step S357. In step S357, the initial phase γ is set to 90 ° to 180 °, and the process proceeds to the end.

  That is, when the primary pressure control is pressure control and the line pressure is not equal to the primary pressure, the first pressure regulating valve 74 is determined to be in the pressure regulation state (state C). When it is determined that the first pressure regulating valve 74 is in the pressure regulating state, the initial phase γ is set to 90 according to the pressure regulating valve opening (full opening side valve opening to full closing side valve opening) depending on the spool position of the first pressure regulating valve 74. Set to ° ~ 180 °. As a specific method for setting the initial phase γ, for example, an initial phase map corresponding to the pressure regulating valve opening degree of the first pressure regulating valve 74 is created in advance based on initial phase experimental data or the like, and the line pressure and the primary pressure are determined. The pressure regulating valve opening degree of the first pressure regulating valve 74 is estimated using a differential pressure or the like. And the initial phase (gamma) according to the pressure regulation valve opening degree of the 1st pressure regulation valve 74 is set using the pressure regulation valve opening estimated value and the initial phase map.

  In step S358, following the determination that the primary pressure control in step S352 is flow control, it is determined whether or not the flow control valve for flow control is fully closed. If YES (fully closed), the process proceeds from step S359 (state D) to step S360. In step S360, the initial phase α is set to 0 °, and the process proceeds to the end.

  If NO in step S358 (valve opening other than fully closed, pressure regulation state or fully open state), proceed to step S361 (state E) → step S362, and in step S362, set the initial phase β to 90 ° And go to the end.

Next, the operation will be described.
The operations of the control device for the belt type continuously variable transmission CVT of the first embodiment are as follows: “BSC permission determination operation and BSC continuation determination operation”, “Belt slip control operation (BSC operation)”, “Feedback control of secondary hydraulic pressure during BSC” The description will be divided into “inhibiting action”, “technical background of BSC by phase difference detection”, and “initial phase setting action during BSC”.

[BSC permission judgment action and BSC continuation judgment action]
While traveling, securing the belt slip control (BSC) travel section as long as possible leads to improved fuel efficiency. Hereinafter, the BSC permission determination action and the BSC continuation determination action reflecting this will be described.

  When the vehicle starts to travel, in the flowchart of FIG. 5, the process proceeds from step S1 to step S2, and unless all the BSC permission determination conditions in step S2 are satisfied, the flow from step S1 to step S2 is repeated. Control is maintained. That is, satisfying all of the BSC permission determination conditions in step S2 is a BSC control start condition.

Here, the BSC permission conditions in the first embodiment will be described below.
(1) The transmission torque capacity of the belt type continuously variable transmission mechanism 4 is stable (the rate of change of the transmission torque capacity is small).
This condition (1) is, for example,
a. | Command torque change rate | <predetermined value
b. Judgment based on two conditions: | command speed ratio change rate | <predetermined value.
(2) The estimation accuracy of the input torque to the primary pulley 42 is within a reliable range.
The condition (2) is determined based on, for example, torque information (estimated engine torque) from the engine control unit 88, the lock-up state of the torque converter 2, the operation state of the brake pedal, the range position, and the like.
(3) Continue the permission states (1) and (2) above for a predetermined time.
In step S2, it is determined whether or not all of the above conditions (1), (2), and (3) are satisfied.

  Therefore, during normal control, when the transmission torque capacity of the belt-type continuously variable transmission mechanism 4 is stable and the estimated accuracy of the input torque to the primary pulley 42 is within a reliable range continues for a predetermined time. The start of belt slip control is permitted.

  As described above, since the start of the belt slip control is permitted by satisfying all the BSC permission conditions not including the speed ratio range condition, regardless of whether the speed ratio side is the low speed ratio side or the high speed ratio side. The belt slip control can be started in a traveling region where the torque change and the gear ratio change are small and stable.

  When the BSC permission determination is made in step S2, the process proceeds to step S3, where the belt type continuously variable transmission mechanism 4 is reduced in input to the belt 44, and the belt that keeps an appropriate slip state without slipping the belt 44. Slip control is performed. Then, following the belt slip control in step S3, in the next step S4, it is determined whether or not all the BSC continuation conditions are satisfied. As long as all the BSC continuation conditions are satisfied, the flow proceeds from step S3 to step S4. Repeatedly, the belt slip control (BSC) is continued.

Here, as the BSC continuation condition in the first embodiment, the conditions (1) and (2) among the BSC permission conditions are used. That is, among the BSC permission conditions, the predetermined time continuation condition (3) is not included in the BSC continuation conditions.
For this reason, during belt slip control, if any of the conditions (1) and (2) is not satisfied, the belt slip control is stopped immediately and the normal control is resumed. Therefore, it is possible to prevent the belt slip control from being continued in a state where the detection accuracy is not guaranteed.

[Belt slip control action (BSC action)]
As described above, the belt slip control executed based on the BSC permission determination and the BSC continuation determination decreases the secondary hydraulic pressure during normal control, and maintains a clamping force that maintains a micro slip state as the belt clamping force. Done. Hereinafter, the belt slip control action reflecting this will be described with reference to FIGS.

At the start of the belt slip control, the secondary oil pressure is obtained by estimating the safety factor and obtaining a clamping force without belt slip. Therefore, the condition that the slip phase difference Sθ is less than the predetermined value 1 is established, and in the flowchart of FIG. 6, the process proceeds from step S331 → step S332 → step S333 → step S334 → step S335 → step S336 → step S337 → step S341. The flow is repeated, and each time this flow is repeated, the command secondary hydraulic pressure decreases with the correction of −ΔPsec, which is the SEC hydraulic pressure correction amount. When the slip phase difference Sθ is equal to or greater than the predetermined value 1, until the slip phase difference Sθ reaches the predetermined value 2, in the flowchart of FIG. 6, step S331 → step S332 → step S333 → step S334 → step S335 → step S336 The process proceeds from step S338 to step S339 to step S341, the SEC hydraulic pressure correction amount is set to zero, and the command secondary hydraulic pressure is maintained. Then, when the slip phase difference Sθ becomes equal to or larger than the predetermined value 2, in the flowchart of FIG. 6, the flow proceeds to step S331 → step S332 → step S333 → step S334 → step S335 → step S336 → step S338 → step S340 → step S341. Thus, the command secondary hydraulic pressure rises in response to the correction of the SEC hydraulic pressure correction amount + ΔPsec.
That is, in the belt slip control, control is performed to maintain a micro slip state in which the slip phase difference Sθ is in a range of a predetermined value 1 or more and less than a predetermined value 2.

The belt slip control will be described with reference to the time chart shown in FIG.
First, the BSC permission conditions (1) and (2) are satisfied at time t1, and the BSC permission conditions (1) and (2) continue (BSC permission conditions (3)). When reaching, the BSC operation flag and the SEC pressure F / B prohibition flag (secondary pressure feedback) from time t2 to time t3 when at least one of the BSC continuation conditions (1) and (2) is not satisfied. Prohibition flag) is set, and belt slip control is performed. If at least one of the BSC continuation conditions is not satisfied due to the accelerator depressing operation slightly before time t3, the return control to the normal control is performed from time t3 to time t4, and after time t4. Normal control will be performed.

  In this way, as is apparent from the accelerator opening characteristic, the vehicle speed characteristic, and the engine torque characteristic, the belt slip control is performed with the solenoid current correction amount characteristic to the secondary hydraulic solenoid 75 during the steady running determination indicated by the arrow C in FIG. As shown, the phase difference θ between the vibration component of the secondary hydraulic pressure and the vibration component of the gear ratio that appears as a result of exciting the secondary hydraulic pressure is monitored, and the current value is increased or decreased. The secondary hydraulic solenoid 75 is normally open (normally open), and when the current value is increased, the secondary hydraulic pressure is decreased.

  By this belt slip control, the actual gear ratio is maintained almost constant although it vibrates with a small amplitude as shown in the actual gear ratio characteristic (Ratio) of FIG. Then, as shown in the phase difference characteristic between the SEC pressure vibration and the Ratio vibration in FIG. 8, the phase difference θ gradually increases as the slip ratio gradually increases with time from the time t2 when the slip ratio is close to zero. The characteristic which converges to (target slip ratio) is shown. Then, as shown in the SEC hydraulic characteristics in FIG. 8, the secondary hydraulic pressure decreases as indicated by an arrow G as time elapses from time t2 having a safety factor, and finally reaches the minimum design pressure. The hydraulic pressure amplitude is added, and the characteristic converges to a sufficient hydraulic pressure level with respect to the actual minimum pressure. When the belt slip control continues for a long time, the actual secondary hydraulic pressure in the design minimum pressure + hydraulic amplitude range is maintained so as to maintain the target value of the phase difference θ (the target value of the slip ratio). .

  Thus, by reducing the secondary hydraulic pressure by belt slip control, the belt friction acting on the belt 44 is reduced, and the drive load for driving the belt-type continuously variable transmission mechanism 4 can be kept low by the reduction in belt friction. . As a result, during the belt slip control by the BSC permission determination, the practical fuel efficiency of the engine 1 can be improved without affecting the running performance.

[Secondary hydraulic feedback control prohibition during BSC]
If the command secondary oil pressure is obtained by feedback control by intentionally vibrating the actual secondary oil pressure during belt slip control, the control becomes unstable or the control diverges. Hereinafter, the feedback control prohibiting action of the secondary hydraulic pressure in the BSC that reflects this will be described.

  For example, when the instruction secondary hydraulic pressure is obtained by feedback control using actual secondary hydraulic pressure information during belt slip control, the deviation varies depending on the vibration component included in the actual secondary hydraulic pressure, and the feedback control amount corresponding to this deviation is continuously added. Therefore, the secondary hydraulic control becomes unstable. In particular, in the belt slip control, when the actual secondary hydraulic pressure is vibrated at a single frequency, the secondary hydraulic pressure by the feedback control may diverge.

  Generally, whether or not the actual secondary hydraulic pressure diverges is determined by the hydraulic feedback control, the frequency response of the shift control, and the hardware response. For this reason, when the secondary hydraulic pressure is vibrated at a single frequency, the frequency response of the hydraulic feedback control and the shift control is taken into consideration, and the vibration frequency is set, or the hydraulic feedback control and the shift control are adjusted according to the vibration frequency. It is necessary to determine the frequency response. However, no matter which method is adopted, the control itself becomes complicated.

  On the other hand, in the first embodiment, since the actual secondary hydraulic pressure information is not used during the belt slip control, the actual secondary hydraulic pressure is allowed to include a vibration component or intentionally include the vibration component. In other words, the estimation accuracy of the belt slip state estimated by monitoring the phase difference θ between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio is ensured. In particular, even if the actual secondary hydraulic pressure is vibrated, the secondary hydraulic pressure control is not affected, so that the phase difference θ between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio can be clearly obtained. By monitoring this phase difference θ, the region immediately before the belt slip can be reliably determined.

  In addition, in the first embodiment, during the belt slip control, the secondary hydraulic control is an open control that does not use the feedback information (actual secondary hydraulic information), and therefore the secondary hydraulic control by the feedback control is maintained during the belt slip control. As described above, it is possible to prevent the control from becoming unstable or the control from diverging.

  Further, in the secondary hydraulic control of the first embodiment, during the belt slip control, only the deviation is set to zero, the feedback control amount until immediately before the transition to the belt slip control is held, and the secondary hydraulic pressure is used by using the held constant feedback control amount. Open control is performed.

  For example, if open control with zero feedback control amount is performed during belt slip control, a feedback control amount with a large value including a steady deviation is added to the target secondary hydraulic pressure at the time of transition from belt slip control to normal control. Therefore, a discontinuous drop occurs in the secondary hydraulic pressure depending on the presence or absence of the feedback control amount, and if the hydraulic pressure drop is large, there is a possibility of a shock that gives the passenger a sense of discomfort.

  On the other hand, during belt slip control, only the deviation is set to zero, and secondary hydraulic open control is performed using a constant feedback control amount. Therefore, as indicated by an arrow H in FIG. Prevents the passenger from feeling uncomfortable due to a drop in the secondary hydraulic pressure when returning from the open control to the feedback control so that the secondary hydraulic pressure rises smoothly and continuously in the region of time t3 can do.

[Technical background of BSC by phase difference detection]
As described above, when the belt slip state is detected by detecting the phase difference between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio, the BSC permission determination area is expanded as much as possible, and the travel section by BSC is lengthened. There is a demand to secure. The technical background of BSC based on phase difference detection that reflects this will be described below.

First, when the belt slip state is detected by detecting the phase difference between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio, the belt slip control (BSC) is performed in a situation where the detection accuracy of the belt slip state decreases. I can't do it.
Here, when | command torque change rate | ≧ predetermined value or | command speed ratio change rate | ≧ predetermined value, the vibration waveform of the vibration component included in the actual secondary hydraulic pressure or the vibration component included in the actual gear ratio This is stretched by the torque change gradient and the gear ratio change gradient and disappears, which causes a reduction in detection accuracy of the belt slip state.
Accordingly, BSC is permitted in a stable steady travel region where there is little torque change or gear ratio change. The substantial BSC start determination includes conditions such as a low throttle opening at a high vehicle speed / high speed stage (high gear ratio side) with a small gear ratio change near a load / road where torque fluctuation is relatively small. . For this reason, even in a stable steady travel region where there is little torque change or gear ratio change, BSC is only permitted at the highest gear ratio and the gear ratio in the vicinity thereof. The BSC is not permitted even in a stable steady state where the change in the gear ratio is small.
Thus, when the travel region where BSC is permitted is limited, there is a problem that the effect of reducing fuel consumption is diminished and BSC is not stable.

The fact that the travel region in which BSC is permitted is limited suggests that the travel condition in which BSC is not permitted has a cause other than the transient travel condition in which the torque change and the gear ratio change are not largely stable. . So, except for transient driving conditions, we analyzed in detail what conditions the belt slip condition detection accuracy decreases,
-The phase of the vibration component of the actual gear ratio detected during BSC changes depending on the conditions.
This condition is due to the primary pressure regulation state which is one of the vibration components of the actual gear ratio.
-There is a difference in shift response depending on the primary pressure regulation state, and for this reason, a difference occurs in the amplitude starting point (called initial phase) of the vibration component of the actual gear ratio.
It was elucidated.
This is because, apart from the transient running condition where the torque change and the gear ratio change are not large and stable, the detection accuracy of the belt slip state is reduced due to the initial phase, and thus the BSC permitted running region has to be narrowed. It became clear why.

Next, the analysis result of the mechanism of why the initial phase occurs will be described.
In BSC, a secondary hydraulic pressure sensor 82 is provided between the secondary-side second pressure regulating valve 77 and the secondary pulley 43, and the second pressure regulating valve 77 is finely moved to vibrate.
This vibration causes a change in thrust of the secondary pulley 43, and this change in thrust affects the balance with the thrust on the primary side. Therefore, in order to maintain the command gear ratio, it is necessary to change the thrust on the primary side in response to the thrust on the secondary side, and the first pressure regulating valve so as to be the primary pressure Ppri corresponding to the change in thrust on the primary side. 74 is adjusted. That is, feedback control is performed so that the first pressure regulating valve 74 that regulates the primary pressure Ppri becomes a balance pressure corresponding to the command primary pressure. This feedback control involves changing the opening of the first pressure regulating valve 74, thereby causing a flow rate fluctuation between the first pressure regulating valve 74 and the hydraulic actuator of the primary pulley 42. As the flow rate of the primary hydraulic circuit changes, the slide pulley 42b of the primary pulley 42 moves / strokes in the axial direction, resulting in a change in gear ratio in which the contact radius between the belt 44 and the primary pulley 42 changes.
As described above, the vibration component included in the actual gear ratio in the BSC includes the gear ratio vibration component generated by the movement and stroke of the slide pulley 43b of the secondary pulley 43 in the axial direction due to the excitation of the secondary hydraulic pressure Psec. The gear ratio vibration component responding to the flow rate fluctuation on the pulley side is superimposed. As a result, when the pressure is adjusted by the first pressure regulating valve 74, the initial phase of the vibration component included in the actual gear ratio is delayed with respect to the initial phase of the vibration component included in the actual secondary hydraulic pressure. Arise.

[Initial phase setting during BSC]
As described above, since the initial phase causes the belt slip state detection accuracy to decrease and the BSC permitted travel region is narrowed, it is necessary to take an initial phase countermeasure to eliminate the influence of this initial phase.
Here, the first pressure regulation valve pressure regulation state determination unit 97 in the hydraulic system of the pressure control valve is configured so that the first pressure regulation valve 74 is in a fully open state (state B) based on sensor signals from the primary hydraulic pressure sensor 87 and the line pressure sensor 89. ) Or the first pressure regulating valve 74 is in a pressure regulation state (state C). In the mechanical high state (state A), the first pressure regulation valve pressure regulation state determination unit 97 does not perform the determination.
Further, the first pressure regulating valve pressure regulation state determination unit 97 in the hydraulic system in the flow control valve is configured so that the first pressure regulation valve 74 is in a fully closed state (state D) based on sensor signals from the primary hydraulic pressure sensor 87 and the line pressure sensor 89. ) Or the first pressure regulating valve 74 is in a pressure regulation state (state E). In the mechanical high state (state A), the first pressure regulation valve pressure regulation state determination unit 97 does not perform the determination.
In this way, there is a system difference between the hydraulic system in the pressure control valve and the hydraulic system in the flow control valve. Hereinafter, based on FIGS. 7 and 9 to 11, the hydraulic system in the pressure control valve that reflects this will be described. The initial phase setting operation during BSC will be described.

  As described above, an initial phase is generated when the pressure is regulated by the first pressure regulating valve 74. This initial phase is different between the shift response in the non-pressure regulation state and the shift response in the pressure regulation state. Differences occur depending on the response. And as shown in FIG.9 and FIG.10, as the pressure regulation mode of the 1st pressure regulation valve 74 from which a shift response differs, as shown in FIG.9 and FIG.10, the 1st pressure regulation valve full open state (B) and the 1st pressure regulation valve pressure regulation state (C) And mechanical high state (A).

The mechanical high state (A) means a state in which the slide pulley 43b of the secondary pulley 43 or the slide pulley 42b of the primary pulley 42 has reached a mechanical high gear ratio at which the stroke cannot be achieved, as shown in FIG.
In this mechanical high state (A), the process proceeds from step S350 to step S363 to step S364 in the flowchart of FIG. 7, and in step S364, the initial phase α is set to 0 °.
The reason for setting the initial phase α to 0 ° in this mechanical high state (A) is that the initial phase of the vibration component included in the actual gear ratio is substantially the same as the initial phase of the vibration component included in the actual secondary hydraulic pressure. By becoming. In the mechanical high gear ratio state, only deformation due to belt tension fluctuation is an influential factor.

The first pressure regulating valve fully opened state (B) refers to the time when the first pressure regulating valve 74 is in the fully opened fixed state. In this first pressure regulating valve fully opened state (B), the process proceeds from step S350 → step S351 → step S352 → step S353 → step S354 → step S355 in the flowchart of FIG. In step S355, the initial phase β is set to 90 °.
The reason why the initial phase β is set to 90 ° in the first pressure regulating valve fully opened state (B) is that the line pressure PL and the primary pressure Ppri are set by the first pressure regulating valve 74 being fully opened (primary pressure Ppri = line pressure PL). This is because the phase of the vibration component included in the actual gear ratio becomes a simple primary response delay with respect to the phase of the vibration component included in the actual secondary hydraulic pressure.

The first pressure regulating valve pressure regulation state (C) refers to the time when the primary pressure Ppri is regulated by the first pressure regulating valve 74 of the belt type continuously variable transmission mechanism 4 as shown in FIG.
In the first pressure regulating valve pressure regulation state (C), the process proceeds from step S350 to step S351 to step S352 to step S353 to step S356 to step S357 in the flowchart of FIG. 7. In step S357, the initial phase γ is 90 °. Set to ~ 180 °.
The reason why the initial phase γ is set to 90 ° to 180 ° in the first pressure regulating valve pressure regulation state (C) is that the line pressure PL and the line pressure PL are controlled by the pressure regulation by the first pressure regulating valve 74 (primary pressure Ppri <line pressure PL). Since the feedback flow rate change occurs between the primary pressures Ppri, the phase of the vibration component included in the actual gear ratio with respect to the phase of the vibration component included in the actual secondary hydraulic pressure is greater than that in the first pressure regulating valve fully opened state (B). Response delay increases. The response delay amount varies depending on the pressure regulating valve opening (full opening side valve opening to full closing side valve opening) depending on the spool position of the first pressure regulating valve 74, oil temperature, pipe orifice diameter, etc. This is because the phase γ needs to be set according to the pressure regulating valve state of the first pressure regulating valve 74.
As shown in FIG. 11, the relationship between the magnitudes of the initial phases α, β, and γ in the three pressure control modes is as follows: mechanical high state (A) <first pressure regulating valve fully opened state (B) <first pressure regulating valve The pressure regulation state (C) is established.

  Here, when the factors affecting the speed change response other than the pressure regulation mode by the first pressure regulation valve 74 are added, it is considered that the thrust change amount due to the secondary pressure excitation is almost constant when the speed ratio is considered constant. However, the influence on the shift response is somewhat different depending on the high side gear ratio, the low side gear ratio, the line pressure, the oil temperature, and the like. Therefore, it is possible to set a more accurate initial phase by taking these influence factors into consideration and correcting the initial phase. At the highest gear ratio, there is no gear ratio fluctuation, and since it is not affected by the hydraulic pressure regulation state, it is fixed regardless of the gear shift response, so that it has the same phase as the first pressure regulation valve fully closed state. Become.

As described above, in the first embodiment, the initial phase that is the difference between the initial hydraulic pressure phase of the actual secondary hydraulic pressure and the actual transmission gear ratio is used to determine the pressure regulation state of the actual primary hydraulic pressure by the first pressure regulating valve 74. Based on the configuration to be set.
In other words, it has been clarified that the initial phase generated in the initial state where there is no belt slip is one of the causes for reducing the detection accuracy of the belt slip state. The initial phase is found to be generated by regulating the primary hydraulic pressure Ppri by the first pressure regulating valve 74, and the initial phase is different depending on the regulated state of the primary hydraulic pressure Ppri.
Therefore, in the flowchart of FIG. 6, the phase difference θ calculated including the initial phases α, β, and γ is corrected by the initial phases α, β, and γ set based on the determination of the regulated state of the actual primary hydraulic pressure. Thus, the corrected phase difference (= slip initial phase Sθ) is the slip phase difference generated by the belt slip after eliminating the initial phase due to the regulated state of the primary hydraulic pressure Ppri.
For this reason, the belt slip state is accurately detected regardless of the pressure regulation state (= gear ratio state) of the primary oil pressure Ppri, so that the BSC depending on the belt slip state detection accuracy is stabilized. Then, the speed ratio range condition for permitting the BSC is relaxed, and as shown in FIG. 9, the range from the low speed ratio including the regions A, B, and C to the high speed ratio is set as the permitted range. The permitted area can be expanded.
As described above, the initial phase α, β, γ, which is one of the causes of reducing the detection accuracy of the belt slip state, is obtained with high accuracy based on the determination of the pressure adjustment state of the actual primary hydraulic pressure. Both stabilization and expansion of the permitted area of the BSC can be achieved. As a result, the traveling section is extended while executing the BSC for suppressing the belt friction, and the effect of reducing the fuel consumption targeted by the BSC is achieved.

In the first embodiment, when the initial phase is set, when the actual primary hydraulic pressure is regulated by the first pressure regulating valve 74, the initial phase γ is set to be larger than the initial phases α and β in the non-regulated state. A large setting was adopted.
That is, since the initial phase depends on the feedback flow rate change between the line pressure PL and the primary pressure Ppri, the pressure regulation state by the first pressure regulation valve 74 with the feedback flow rate change and the first pressure regulation valve without the feedback flow rate change. 74 and the non-pressure-regulated state. Therefore, by setting the initial phase γ in the pressure regulation state to be larger than the initial phases α and β in the non-pressure regulation state, the first pressure regulating valve 74 is in the pressure regulation state or the non-pressure regulation state. Regardless of whether the belt slip condition is detected or not.

In the first embodiment, when the initial phase is set, the non-regulated state in which the actual primary hydraulic pressure is not regulated by the first regulating valve 74 is divided into a first regulating valve fully closed state (A) and a first regulating valve fully opened state (B )
Mechanical high state (A) <first pressure regulating valve fully opened state (B) <first pressure regulating valve pressure regulating state (C)
Therefore, the configuration in which the magnitudes of the initial phases α, β, and γ are set is adopted.
That is, in the non-regulated state of the first pressure regulating valve 74, the fully closed state where there is no change in flow rate due to the interruption of the line pressure PL and the primary pressure Ppri, and the primary pressure Ppri matches the line pressure PL due to the oil passage communication. There are two modes: a fully open state where there is no feedback flow rate change.
Accordingly, when the first pressure regulating valve 74 is in the non-pressure-regulating state, the fully-closed state is set to the fully-closed state by setting the initial phase β in the fully-opened state larger than the initial phase α in the fully-closed state. Regardless of the fully open state, the detection accuracy of the belt slip state is ensured.

In Example 1, when the initial phase is set, the initial phase α is set to 0 ° in the mechanical high state (A), the initial phase β is set to 90 ° in the first pressure regulating valve full open state (B), A configuration is adopted in which the initial phase γ is set in the range of 90 ° to 180 ° according to the pressure regulating valve opening degree of the first pressure regulating valve 74 in the 1 pressure regulating valve pressure regulating state (C).
That is, in the mechanical high state (A), there is no flow rate change due to the interruption of the line pressure PL and the primary pressure Ppri, and no initial phase is generated due to the flow rate change. When the first pressure regulating valve is fully opened (B), the primary pressure Ppri coincides with the line pressure PL due to the oil passage communication, but there is no feedback flow rate change, and the initial phase due to the flow rate change is a simple primary delay. In the first pressure regulating valve pressure regulating state (C), a feedback flow rate change occurs according to the pressure regulating valve opening degree of the first pressure regulating valve 74.
Therefore, the pressure regulation state of the first pressure regulating valve 74 is divided into three pressure regulating modes, and the initial phases α, β, γ are set for each of the three pressure regulating modes. In the mode, the detection accuracy of the belt slip state is ensured.

In the first embodiment, when the initial phase is set, the pressure regulation state of the first pressure regulation valve 73 is determined based on the sensor detection values of the line pressure PL from the line pressure sensor 89 and the primary oil pressure Ppri from the primary oil pressure sensor 87. The configuration to adopt was adopted.
That is, it is necessary to discriminate the opening of the pressure regulating valve among the pressure regulating states of the first pressure regulating valve 73, particularly in the first pressure regulating valve pressure regulating state (C). On the other hand, the line pressure sensor 89 and the primary oil pressure sensor 87 are existing sensors in the system, and new sensors such as a spool stroke sensor of the first pressure regulating valve 73 are not added. Further, by monitoring the line pressure level and the magnitude of the differential pressure, the pressure regulating valve opening degree of the first pressure regulating valve 73 can be accurately determined.
Therefore, by determining the pressure regulation state of the first pressure regulation valve 73 using the sensor detection value from the existing sensor in the system, the pressure regulation state of the first pressure regulation valve 73 is inexpensive and the pressure regulation valve opening degree. Are accurately identified.

Next, the effect will be described.
In the control device for the belt type continuously variable transmission CVT according to the first embodiment, the following effects can be obtained.

(1) A primary pulley 42 that is input from a drive source (engine 1), a secondary pulley 43 that is output to drive wheels 6 and 6, a belt 44 that spans the primary pulley 42 and the secondary pulley 43, and the primary pulley In the control device for the belt-type continuously variable transmission CVT, comprising: a first pressure regulating valve 74 that regulates the actual primary hydraulic pressure to 42; and a second pressure regulating valve 77 that regulates the actual secondary hydraulic pressure to the secondary pulley 43.
When the belt slip control permission condition is satisfied, the secondary hydraulic pressure is applied to the secondary pulley 43 to calculate the phase difference θ between the vibration component included in the actual secondary hydraulic pressure and the vibration component included in the actual gear ratio. Means (phase difference calculation unit 96);
The initial phases α, β, and γ, which are the differences between the initial hydraulic phase that is the amplitude starting point of the vibration component characteristic of the actual secondary hydraulic pressure and the initial gear ratio phase that is the amplitude starting point of the vibration component characteristic of the actual gear ratio, are Initial phase setting means (initial phase setting unit 98) for setting based on the determination of the pressure regulation state of the actual primary oil pressure by the one pressure regulating valve 74;
The belt slip is corrected by correcting the phase difference θ calculated by the phase difference calculating means (phase difference calculating section 96) with the initial phases α, β, and γ set by the initial phase setting means (initial phase setting section 98). Belt slip state detection means (belt slip state detection unit 100) for detecting the state;
Based on the detection of the belt slip state by the belt slip state detection means (belt slip state detection unit 100), the command secondary hydraulic pressure is determined so that the belt 44 maintains the micro slip state with respect to the pulleys 42 and 43, Belt slip control means (secondary hydraulic pressure correction amount determining unit 101) for adjusting secondary hydraulic pressure by the second pressure regulating valve 77;
(FIG. 4).
As described above, the initial phase α, β, γ, which is one of the causes for reducing the detection accuracy of the belt slip state, is obtained with high accuracy based on the determination of the actual primary hydraulic pressure adjustment state. It is possible to achieve both the stabilization of the slip control (BSC) and the expansion of the permitted area of the belt slip control (BSC).

(2) The initial phase setting means (initial phase setting unit 98) has an initial phase α, β when the actual primary hydraulic pressure is regulated by the first pressure regulating valve 74 and when it is not regulated. The initial phase γ is set larger than
For this reason, in addition to the effect of (1), the detection accuracy of the belt slip state can be ensured regardless of whether the first pressure regulating valve 74 is in the pressure regulating state or the non-pressure regulating state.

(3) The initial phase setting means (initial phase setting unit 98) includes a first pressure regulating valve pressure regulating state (C) in which the actual primary hydraulic pressure is regulated by the first pressure regulating valve 74, and the first pressure regulating valve 74. When the non-regulated state in which the actual primary hydraulic pressure is not regulated by is divided into the mechanical high state (A) and the first pressure regulating valve fully opened state (B),
Mechanical high state (A) <first pressure regulating valve fully opened state (B) <first pressure regulating valve pressure regulating state (C)
The magnitudes of the initial phases α, β, and γ are set based on
For this reason, in addition to the effect (2), when the first pressure regulating valve 74 is in the non-regulated state, it is possible to ensure the detection accuracy of the belt slip state regardless of whether it is in the fully closed state or the fully open state.

(4) The initial phase setting means (initial phase setting unit 98) sets the initial phase α to 0 ° in the mechanical high state (A), and sets the initial phase β to 90 in the first pressure regulating valve fully opened state (B). The initial phase γ is set in the range of 90 ° to 180 ° according to the pressure regulating valve opening of the first pressure regulating valve 74 in the first pressure regulating valve pressure regulating state (C).
Therefore, in addition to the effect of (3), by setting the initial phases α, β, and γ for each of the three pressure control modes of the first pressure control valve 74, in any pressure control mode of the first pressure control valve 74, The detection accuracy of the belt slip state can be ensured.

(5) A line pressure sensor 89 is provided on the upstream side of the first pressure regulating valve 74, and a primary hydraulic pressure sensor 87 is provided on the downstream side of the first pressure regulating valve 74,
The initial phase setting means (initial phase setting unit 98) determines the pressure regulation state of the first pressure regulating valve 74 based on sensor detection values of the line pressure PL and the primary hydraulic pressure Ppri.
For this reason, in addition to the effects (1) to (4), it is possible to accurately determine the pressure regulation state of the first pressure regulating valve 73 at low cost using the existing sensor and including the pressure regulating valve opening. it can.

  As mentioned above, although the control apparatus of the belt type continuously variable transmission of the present invention has been described based on the first embodiment, the specific configuration is not limited to the first embodiment, and each claim of the claims Design changes and additions are permitted without departing from the spirit of the invention according to the paragraph.

  In the first embodiment, an example in which an appropriate vibration component is given to the instruction secondary hydraulic pressure as the means for vibrating is shown, but an example in which an appropriate vibration component is given to the solenoid current value may be used.

  In the first embodiment, an example of application to an engine vehicle equipped with a belt-type continuously variable transmission is shown. However, the present invention is applied to a hybrid vehicle equipped with a belt-type continuously variable transmission or an electric vehicle equipped with a belt-type continuously variable transmission. It can also be applied to. In short, the present invention can be applied to any vehicle equipped with a belt-type continuously variable transmission that performs shift control using the first pressure regulating valve and the second pressure regulating valve.

Claims (7)

A primary pulley that is input from a drive source, a secondary pulley that is output to a drive wheel, a belt that spans the primary pulley and the secondary pulley, a first pressure regulating valve that regulates an actual primary hydraulic pressure to the primary pulley, A control device for a belt-type continuously variable transmission, comprising: a second pressure regulating valve that regulates the actual secondary hydraulic pressure to the secondary pulley;
Phase difference calculating means for exciting a secondary hydraulic pressure to the secondary pulley and calculating a phase difference between a vibration component included in the actual secondary hydraulic pressure and a vibration component included in the actual gear ratio when the belt slip control permission condition is satisfied; ,
The initial phase, which is the difference between the initial hydraulic phase that is the amplitude starting point of the vibration component characteristic of the actual secondary hydraulic pressure, and the initial transmission gear ratio phase that is the amplitude starting point of the vibration component characteristic of the actual gear ratio, is expressed by the first pressure regulating valve. Initial phase setting means for setting based on the determination of the regulation state of the primary hydraulic pressure;
Belt slip state detecting means for detecting a belt slip state by correcting the phase difference calculated by the phase difference calculating means by the initial phase set by the initial phase setting means;
A belt that determines a command secondary hydraulic pressure so that the belt maintains a micro slip state with respect to both pulleys based on detection of a belt slip state by the belt slip state detection means, and regulates an actual secondary hydraulic pressure by the second pressure regulating valve. Slip control means;
A control device for a belt-type continuously variable transmission. In the control device for the belt type continuously variable transmission according to claim 1,
The initial phase setting means sets the initial phase to be larger when compared with the initial phase when the actual primary oil pressure is adjusted by the first pressure regulating valve than when the non-regulated state is being adjusted. Control device for belt type continuously variable transmission. In the control device for the belt-type continuously variable transmission according to claim 2,
The first pressure regulating valve and the second pressure regulating valve comprise a hydraulic system that is a pressure control valve,
The initial phase setting means includes a first pressure regulating valve pressure regulating state in which the actual primary hydraulic pressure is regulated by the first pressure regulating valve, and a non-pressure regulating state in which the actual primary hydraulic pressure is not regulated by the first pressure regulating valve, When divided into the mechanical high state and the first pressure regulating valve fully open state,
A control device for a belt-type continuously variable transmission, wherein the magnitude of the initial phase is set according to the relationship of mechanical high state <first pressure regulating valve fully opened state <first pressure regulating valve pressure regulating state. In the control device for the belt-type continuously variable transmission according to claim 2,
The first pressure regulating valve and the second pressure regulating valve comprise a hydraulic system that is a flow control valve,
The initial phase setting means includes a first pressure regulating valve fully closed state in which the first pressure regulating valve is not fully closed and pressure regulation, and the first pressure regulating valve has a valve opening other than a fully closed state and is in a pressure regulating state or a fully opened state. When divided into the first pressure regulating valve non-fully closed state by
A control device for a belt-type continuously variable transmission, wherein the magnitude of the initial phase is set according to the relationship of the first pressure regulating valve fully closed state <the first pressure regulating valve non-fully closed state. In the control device for the belt type continuously variable transmission according to claim 3,
The initial phase setting means sets the initial phase to 0 ° when in the mechanical high state, sets the initial phase to 90 ° when the first pressure regulating valve is fully open, and sets the initial phase when the first pressure regulating valve is in the regulated state. A control device for a belt-type continuously variable transmission, characterized in that it is set in a range of 90 ° to 180 ° in accordance with the pressure regulating valve opening of the first pressure regulating valve. In the control device for the belt type continuously variable transmission according to claim 3,
The initial phase setting means sets the initial phase to 0 ° when the first pressure regulating valve is fully closed, and sets the initial phase to 90 ° when the first pressure regulating valve is not fully closed. Control device for continuously variable transmission. In the control apparatus of the belt type continuously variable transmission according to any one of claims 1 to 6,
A line pressure sensor is provided upstream of the first pressure regulating valve, and a primary hydraulic pressure sensor is provided downstream of the first pressure regulating valve;
The control device for a belt-type continuously variable transmission, wherein the initial phase setting means determines a pressure regulation state of the first pressure regulation valve based on sensor detection values of a line pressure and a primary oil pressure.

Images