JP6913249B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a continuously variable transmission control device suitable for use in a continuously variable transmission whose gear ratio is controlled by flood control.

When controlling the automatic transmission hydraulically, it is necessary to consider the hydraulic responsiveness. This hydraulic responsiveness is such that when the oil pressure before changing the oil pressure is high, the rise is fast and the fall is slow, and when the oil pressure before changing the hydraulic pressure is low, the rise is slow and the fall is slow. It has the characteristic that the fall is quick.

Patent Document 1 discloses a technique for realizing feedback control with good responsiveness while ensuring stability by setting an optimum gain corresponding to hydraulic responsiveness when the operating hydraulic pressure of an automatic transmission is changed. There is. Specifically, the value of the operating oil pressure before the change when the shift state changes is detected, and the gain of the feedback control is changed based on the detected pre-change oil pressure.

However, as in the technique of Patent Document 1, when the gain of feedback control is simply defined according to the oil pressure before the change when the operating oil pressure of the automatic transmission is changed, the sensitivity of the hydraulic response (hereinafter, "hydraulic response sensitivity"). The relationship between (abbreviated as) and gain may not be appropriate. If the gain is too large or too small for the hydraulic response sensitivity, control instability may occur.
Further, if the gain is too small with respect to the hydraulic response sensitivity, the control response may be unnecessarily lowered. Even when a continuously variable transmission is applied to an automatic transmission, there is a concern that such a problem may occur. In particular, when the gear ratio of a continuously variable transmission is feedback-controlled, a decrease in control responsiveness and a change in control responsiveness accompanying the feedback control greatly deteriorates control performance, which is not preferable.

Japanese Unexamined Patent Publication No. 4-272567

The present invention has been devised in view of such a problem, and is a continuously variable transmission capable of suppressing a decrease in the hydraulic response sensitivity when performing feedback control for changing the operating hydraulic pressure in the continuously variable transmission. It is intended to provide a control device for the above.

(1) In order to achieve the above object, the present invention has, as one aspect, a hydraulic continuously variable transmission having a primary pulley and a secondary pulley and a belt wound around the primary pulley and the secondary pulley. By feedback-controlling the flood control valve based on the deviation between the target value of the control parameter (for example, the target gear ratio) and the actual value of the control parameter (for example, the actual gear ratio) and the control gain in the control device of the machine. , A control means that controls the oil pressure of the hydraulic oil in the oil chamber of the primary pulley or the secondary pulley to control the shift so that the gear ratio becomes the target gear ratio, and the shift that changes the gear ratio to the target gear ratio. Based on at least two of a plurality of hydraulic response related parameters including the command speed, the hydraulic command value which is the command value of the hydraulic pressure, the front-rear pressure difference of the hydraulic control valve, and the volume of the oil chamber. A gain changing means for calculating the hydraulic response sensitivity and changing the control gain based on the calculated hydraulic response sensitivity is provided.

(2) The gain changing means is based on three of four hydraulic response-related parameters of the shift command speed, the hydraulic command value, the front-rear pressure difference, and the volume of the oil chamber. It is preferable to calculate the hydraulic responsiveness.

(3) It is preferable that the gain changing means changes the control gain stepwise based on the hydraulic responsiveness.

(4) The gain changing means preferably changes the control gain in two stages based on the hydraulic responsiveness.

(5) The control means performs the shift control by performing the feedback control on the primary pulley, and the gain changing means assumes that the volume of the oil chamber of the primary pulley is the maximum, and the shift command is given. It is preferable to calculate the hydraulic response based on the characteristics of the three hydraulic response-related parameters of the speed, the hydraulic command value, and the front-rear pressure difference.

According to the present invention, when controlling the gear ratio by feedback control, the control stability can be ensured by appropriately calculating the hydraulic response sensitivity and setting the control gain based on the calculation.

It is a block diagram which shows the main part of the continuously variable transmission and its control device which concerns on one Embodiment of this invention. It is a block diagram explaining the hydraulic control system of the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a block diagram explaining the feedback control of the hydraulic control system of the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a figure which shows the relationship with the gear ratio of the oil chamber volume which is one of the hydraulic response related parameters which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the front-rear pressure difference of a hydraulic control valve which is one of the hydraulic response related parameters which concerns on one Embodiment of this invention, and a gear ratio, (a) is upshift, (b) is down. Regarding shift time. It is a figure which shows the relationship between the shift command speed which is one of the hydraulic response related parameters which concerns on one Embodiment of this invention, and a pressure adjustment position. It is a figure which shows the relationship between the hydraulic command value which is one of the hydraulic response related parameters which concerns on one Embodiment of this invention, and the bulk modulus k of hydraulic fluid. It is a graph which shows the characteristic of the hydraulic response sensitivity with respect to the hydraulic response related parameter which concerns on one Embodiment of this invention, (a) is the equal response about the shift command speed and the hydraulic command value when the front-rear pressure difference and the oil chamber volume are constant. Lines are shown, (b) shows an equal response line regarding the oil chamber volume and the oil pressure command value when the front-rear pressure difference and the shift command speed are constant, and (c) shows the shift command speed when the front-rear pressure difference is constant. The isoresponse line regarding the oil chamber volume and the oil pressure command value is shown. It is a figure explaining the point of interest of setting with respect to the hydraulic response sensitivity of the control gain used for the feedback control by the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a figure explaining the calculation method of the hydraulic response sensitivity ω for setting the feedback control gain by the control device of the continuously variable transmission which concerns on one Embodiment of this invention, and (a) is an example at the time of the specific front-rear pressure difference. (B) shows an example when there is a general front-rear pressure difference. The figure explaining the interpolation calculation method of the hydraulic response sensitivity ω with respect to the front-rear pressure difference when calculating the hydraulic response sensitivity ω for setting the feedback control gain by the control device of the continuously variable transmission which concerns on one Embodiment of this invention. Is. It is a figure which shows the map which sets the feedback control gain from the hydraulic response sensitivity ω by the control device of the continuously variable transmission which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiments shown below are merely examples, and there is no intention of excluding the application of various modifications and techniques not specified in the following embodiments. Each configuration of the following embodiments can be variously modified and implemented without departing from the purpose thereof, and can be selected as necessary or combined as appropriate.

[Overall system configuration]
FIG. 1 is a configuration diagram showing a main part of a continuously variable transmission and a control device thereof according to the present embodiment.
As shown in FIG. 1, the stepless transmission (CVT) 1 is arranged and illustrated in parallel with an input shaft 2 which is drive-connected to an output shaft of an engine (internal engine) which is a drive source and is not shown. The output shaft 3 is driven and connected to the drive wheels, the primary pulley 4 is connected to the input shaft 2, the secondary pulley 5 is connected to the output shaft 3, and the primary pulley 4 and the secondary pulley 5 are wound around. It is provided with an endless belt 6.

The primary pulley 4 has a fixed sheave 41, a movable sheave 42, and a primary oil chamber 43 that moves the movable sheave 42 in the axial direction.
The secondary pulley 5 has a fixed sheave 51, a movable sheave 52, and a secondary oil chamber 53 that moves the movable sheave 52 in the axial direction.

Continuously variable transmission 1, for supplying hydraulic fluid to the primary fluid chamber 43 and the secondary oil chamber 53, the hydraulic pump 61, pressure regulating hydraulic oil discharged from the hydraulic pump 61 to a predetermined line pressure P _L line a pressure control valve (pressure regulator valve) 62, the line pressure and P _L primary pressure control valve 63 for pressurizing regulating the primary pressure Ppri as source pressure, secondary pressure control valve for pressure regulation in the secondary pressure Psec the line pressure P _L as source pressure It has 64 and. Each of the control valves 62, 63, 64 is a control valve operated by a solenoid, and the output hydraulic pressure is adjusted by controlling the current to each of the solenoids 62a, 63a, 64a by the CVT ECU (CVT electronic control unit) 7. Will be done.

The CVTEC 7 detects the rotation speed of the primary pulley 4 (unit time rotation speed, primary pulley rotation speed) Npri, the primary rotation sensor 81, and the rotation speed of the secondary pulley 5 (unit time rotation speed, secondary pulley rotation speed) Nsec. Various sensors such as a secondary rotation sensor 82, a primary pressure sensor 83 that detects the pressure (primary pressure) Ppri of the primary oil chamber 43, and a secondary pressure sensor 84 that detects the pressure (secondary pressure) Psec of the secondary oil chamber 53 are connected. , These sensor information and switch information are input. Further, the CVT ECU 7 is connected to the engine ECU (engine electronic control unit) 8 so as to be able to transmit information.

The continuously variable transmission 1 applies as low a thrust as possible to each of the pulleys 4 and 5 within a range in which slip does not occur between the belt 6 and the pulleys 4 and 5, and when the gear ratio R is changed, the primary pulley 4 A differential thrust is applied between the and the secondary pulley 5 to drive the movable sheaves 42 and 52 in the axial direction so that the target gear ratio Rt is achieved. These thrusts and differential thrusts are performed by controlling the primary pressure Ppri and the secondary pressure Psec by the CVT ECU 7.

[Flood control system configuration]
Therefore, CVTECU7 the line pressure control section 71 for controlling the line pressure P _L, the primary pressure control section 72 for controlling the primary pressure Ppri, and a secondary pressure control section 73 for controlling the secondary pressure Psec.
Further, the CVT ECU 7 includes a gear ratio calculation unit 74 that calculates the actual gear ratio Rr from the primary pulley rotation speed Npri and the secondary pulley rotation speed Nsec.

Line pressure control unit 71 outputs a predetermined control command (line pressure command value P _L _c) to the line pressure solenoid 62a.
The primary pressure control unit 72 outputs a control command (primary pressure instruction value Ppri_c) for obtaining a predetermined primary pressure target value Ppri_t to the primary hydraulic solenoid 64a.
The secondary pressure control unit 73 outputs a control command (secondary pressure instruction value Psec_c) for obtaining a predetermined secondary pressure target value Psec_t to the secondary hydraulic solenoid 63a.

Next, the basic secondary pressure command value Psec_c, primary pressure command value Ppri_c, the setting of the line pressure command value P _L _c be described.
As shown in FIG. 2, the secondary pressure control unit 73 calculates the torque capacity (required torque transmission capacity) transmitted by the continuously variable transmission 1 based on the output information obtained from the engine ECU 8, and is required from this transmission torque capacity. The secondary pressure target value Psec_t corresponding to the thrust is derived and the secondary pressure indicated value Psec_c is set. The secondary pressure indicated value Psec_c is set by adding the feedback correction amount based on the secondary actual pressure Psec to the secondary pressure target value Psec_t.

As shown in FIG. 2, the primary pressure control unit 72 is based on the target gear ratio Rt obtained from the engine ECU 8, the actual gear ratio Rr calculated by the gear ratio calculation unit 74, and the secondary pressure instruction value Psec_c, and the primary pressure target value Ppri_t. Is set, and the primary pressure indicated value Ppri_c is set from the primary pressure target value Ppri_t and the primary actual pressure Ppri. That is, in the primary pressure control unit 72, the relationship with the secondary pressure indicated value Psec_c becomes according to the target difference thrust by the feedback control based on the deviation (Rt-Rr) between the target gear ratio Rt and the actual gear ratio Rr. The primary pressure indicated value Ppri_c is set while considering the primary actual pressure Ppri by giving the primary pressure target value Ppri_t.

The line pressure control unit 71 can achieve the secondary pressure indicated value Psec_c and the primary pressure indicated value Ppri_c based on the secondary pressure indicated value Psec_c and the primary pressure indicated value Ppri_c, so that the secondary pressure indicated value Psec_c and the primary pressure indicated value can be achieved. setting the margin (differential pressure .DELTA.P0) only high line pressure command value P _L _c than the larger of Ppri_c.

By the way, the hydraulic control by the primary pressure control unit 72 is a feedback control that brings the actual gear ratio Rr closer to the target gear ratio Rt, but when the primary pressure Ppri is changed, if the control gain of the feedback control is constant, the control is not possible. May lead to stability. That is, if the control gain is too large or too small with respect to the hydraulic response sensitivity, control instability may occur. Further, if the control gain is too small with respect to the hydraulic response sensitivity, the control response may be unnecessarily lowered. If control instability is caused in shift control, the shift feeling is deteriorated and the shift performance is deteriorated.

Therefore, in this device, the CVT ECU 7 is provided with a gain changing unit (gain changing means) 75 that changes the control gain of the feedback control based on the hydraulic responsiveness when the primary pressure Ppri is changed.
The gain changing unit 75 pays attention to the parameter (hydraulic response related parameter) that correlates with the hydraulic response, calculates the hydraulic response sensitivity ω from the hydraulic response related parameter, and controls the control gain (gain coefficient) from the hydraulic response sensitivity ω. Set Κ.

The parameters related to the hydraulic response include the shift command speed dx / dt, the primary pressure instruction value Ppri_c (hydraulic command value), which is the command value of the primary pressure Ppri, and the front-rear pressure difference between the primary pressure control valve 63 (hydraulic control valve). There is a pressure difference (pressure difference) ΔP between the upstream side and the downstream flow side with respect to the primary pressure control valve 63, which is a hydraulic control valve, and a volume V (plunger volume) of the primary oil chamber 43.

Of these, as shown in FIG. 4, the volume V of the primary oil chamber 43 changes according to the gear ratio R and changes substantially linearly with respect to the stroke amount x of the movable sheave 42, but the gear ratio R is LOW. The stroke amount x with respect to the gear ratio R is smaller toward the side. Therefore, the closer the gear ratio R is to the LOW side, the higher the hydraulic response sensitivity ω.

Longitudinal pressure difference ΔP of the primary pressure control valve 63, the upshift, FIG. 5 (a), a long primary real pressure Ppri the secondary real pressure Psec above, the line pressure command value P _L _c and primary real Although the difference between the pressure _{Ppri (= P L _c-Ppri} = ΔP0), is less than primary real pressure Ppri the secondary real pressure Psec, the difference in margin to the difference between the secondary real pressure Psec and the primary actual pressure Ppri The value is obtained by adding the pressure ΔP0 (= Psec-Ppri + ΔP0).
Further, during the downshift, as shown in FIG. 5B, the hydraulic oil drains, so that the front-rear pressure difference ΔP is the difference (= Ppri-Patm) between the primary actual pressure Ppri and the atmospheric pressure Patm.
The larger the front-rear pressure difference ΔP, the higher the hydraulic response sensitivity ω.

The shift command speed α (= dx / dt) is the throttle ratio of the primary pressure control valve 63 (A ₂ / A ₁ , where A ₁ is the flow path area upstream of the primary pressure control valve 63, and A ₂ is the primary pressure control valve. It corresponds to the flow path area in 63) and depends on the pressure adjusting position of the primary pressure control valve 63 as shown in FIG.
That is, although not shown, the control valve includes a spool chamber, each port formed around the spool chamber, and a spool equipped in the spool chamber so as to be movable in the axial direction. It has a land portion that closes the port, an annular oil passage portion that has a reduced diameter, and a notch portion that is cut out so as to communicate with the oil passage portion on the outer periphery of the end portion of the land portion. The pressure adjustment position of the primary pressure control valve 63 includes a lap position where the land portion wraps around the port and closes the port, a notch position where the notch portion opens to the port, and a port position where the annular oil passage portion opens to the port. There is. As shown in FIG. 6, if the pressure adjustment position is the valve lap position, the shift command speed α is 0, and if the pressure adjustment position is the valve notch position, the notch portion opens the port at the shift command speed α. It increases according to the amount, and if the pressure regulation position is the port position of the valve, the annular oil passage portion further increases according to the amount of opening of the port.
Such a pressure adjustment position is determined by the shift flow rate, and the shift flow rate depends on the shift speed.
The larger the shift command speed α, the higher the hydraulic response sensitivity ω.
The shift command speed α is a value for setting the speed at which the gear ratio R is changed from the actual gear ratio Rr to the target gear ratio Rt (time change rate of the gear ratio R), and is mainly the target gear ratio Rt and the actual gear ratio Rr. , The temperature of the hydraulic oil, the shifting direction (upshift or downshift), etc. are set.

The primary pressure indicated value Ppri_c affects the bulk modulus k of the hydraulic oil, and as shown in FIG. 7, the higher the primary pressure indicated value Ppri_c, the larger the bulk modulus k of the hydraulic oil.
Further, the larger the bulk modulus k of the hydraulic oil, the higher the hydraulic response sensitivity ω. Therefore, the higher the primary pressure indicated value Ppri_c, the higher the hydraulic response sensitivity ω.

Next, with reference to FIG. 8, the characteristics of the hydraulic response sensitivity ω with respect to a plurality of hydraulic response related parameters will be described.
FIG. 8A connects points where the equivalence lines (hydraulic response sensitivity ω) relating to the shift command speed (dx / dt) and the primary pressure indicated value Ppri_c when the front-rear pressure difference ΔP and the oil chamber volume V are constant are equal. Line), and corresponds to a two-dimensional map for obtaining the hydraulic response sensitivity ω from the shift command speed (dx / dt) and the primary pressure indicated value Ppri_c.
FIG. 8B shows an isoresponse line regarding the oil chamber volume V and the primary pressure instruction value Ppri_c when the front-rear pressure difference ΔP and the shift command speed (dx / dt) are constant, and shows the oil chamber volume V and the primary pressure instruction. Corresponds to the two-dimensional map for obtaining the hydraulic response sensitivity ω from the value Ppri_c.
FIG. 8 (c) shows isoresponse lines relating to the shift command speed (dx / dt), the oil chamber volume V, and the primary pressure indicated value Ppri_c when the front-rear pressure difference ΔP is constant, and FIGS. 8 (a) and 8 (c) show. Corresponds to the three-dimensional map for obtaining the hydraulic response sensitivity ω from the speed change command speed (dx / dt), the oil chamber volume V, and the primary pressure indicated value Ppri_c, which are combined with (b).
The three-dimensional region shaded in FIG. 8C is a zone (danger zone) that is not preferable in terms of control because the hydraulic response sensitivity ω is too low and causes control instability.

Next, the points of interest when setting the control gain Κ corresponding to the hydraulic response sensitivity ω will be described.
FIG. 9 shows a graph showing the characteristics of the hydraulic response sensitivity ω with respect to the primary pressure indicated value Ppri_c (upper right, hydraulic response sensitivity diagram) and a graph showing the characteristics of the hydraulic response sensitivity ω with respect to the feedback control gain Κ (upper left, hydraulic response and gain). The figure of the margin) and the graph which shows the characteristic of the rotation deviation with respect to the feedback control gain Κ (lower left, the figure of the control gain and the rotation deviation) are shown in correlation.
In FIG. 9, solid arrows and circles indicate the response characteristics of the hydraulic oil at a high flow rate (for example, kickdown), and dashed arrows and circles indicate the response characteristics of the hydraulic oil at a low flow rate (for example, load load). (When driving, etc.) is shown.

In the hydraulic response sensitivity diagram, as shown by the solid circles, the hydraulic response sensitivity ω at high flow rate is high, and the hydraulic response sensitivity ω at low flow rate is low.
In the figure of hydraulic response and gain margin, the shaded area is the area that exceeds the control stability limit, and the control stability is ensured by setting the control gain Κ for the flood control response to the area separated from this shaded area by a certain amount or more. can do. However, excessive separation from the shaded area poses new control challenges.

Since the hydraulic response sensitivity ω at high flow rate is high, control stability can be ensured even if the control gain Κ is set relatively high. If the control gain Κ is set relatively low when the hydraulic response sensitivity ω is high, stability can be ensured, but the rotation deviation becomes large and the shifting performance (overshoot amount) greatly exceeds the target value. New control challenges arise.
On the other hand, since the hydraulic response sensitivity ω at a low flow rate is low, control stability cannot be ensured unless the control gain Κ is set relatively low.
Therefore, as shown in the figure of control gain and rotation deviation, the control gain Κ is set high when the hydraulic response sensitivity ω at high flow rate is high, and the control gain Κ is set low when the hydraulic response sensitivity ω at low flow rate is low. It is preferable to do so.

Next, the calculation of the hydraulic response sensitivity ω of the present embodiment and the method of setting the control gain Κ from the hydraulic response sensitivity ω will be described with reference to FIGS. 10 to 12.
As described above, there are four parameters related to hydraulic response, and if you try to obtain the hydraulic response sensitivity ω using all four parameters, you will have to use a two-dimensional map x two-dimensional map, and the calculation configuration will be complicated. As a result, it becomes difficult to predict the operation and manage the constants. Therefore, in the present embodiment, the hydraulic response sensitivity ω is obtained using three of the four parameters.

Here, of the four parameters, the shift command speed dx / dt, the primary pressure instruction value Ppri_c which is the command value of the primary pressure Ppri, and the front-rear pressure difference ΔP of the primary pressure control valve 63 are used. Regarding the volume V of the primary oil chamber 43, the hydraulic response sensitivity ω is obtained assuming that the maximum volume (the highest gear ratio R) is the worst condition (it is difficult to secure control stability).

As shown in FIGS. 10 (a) and 10 (b), the shift command speed dx / dt and the primary pressure indicated value Ppri_c at each of the front-rear pressure differences ΔP1 to ΔPn (n front-rear pressure difference values taken at predetermined intervals). Create an equi-ω line (iso-response line) related to and. As a result, the hydraulic response sensitivity ω can be obtained from the front-rear pressure difference ΔPk, the shift command speed dx / dt, and the primary pressure indicated value Ppri_c.
However, the actual front-rear pressure difference ΔPx may not be on ΔPn shown in FIGS. 10 (a) and 10 (b). In this case, as shown in FIG. 11, two ΔPk and ΔP close to the value ΔPx. The hydraulic response sensitivity ωx is obtained by using the linear interpolation method for (k + 1) and k: 1 to (1-n).

After obtaining the hydraulic response sensitivity ω in this way, the control gain Κ is set corresponding to the hydraulic response sensitivity ω as shown in FIG.
In the example shown in FIG. 12, if the hydraulic response sensitivity ω is equal to or higher than the threshold value ω0, a relatively high control gain Κ is set, and if the hydraulic response sensitivity ω is less than the threshold value ω0, a relatively low control gain Κ is set.

For example, when PID control is used for feedback control of the gear ratio, the deviation e (t) between the target value (target gear ratio) Rt and the actual value (actual gear ratio) Rr is calculated as shown in FIG. Then, from a plurality of parameters related to the hydraulic response (shift command speed dx / dt, primary pressure indicated value Ppri_c, front-rear pressure difference ΔP of the primary pressure control valve 63, volume V of the primary oil chamber 43), the hydraulic response sensitivity ω Is calculated, and the respective control gains Κp, Κi, Κd are set from the hydraulic response sensitivity ω.
Then, the P control amount Κpe (t), the I control amount Κi∫e (t) dt, and the D control amount Κd de (t) / dt are calculated, and the sum of these is used as the control amount for PID control.
However, the feedback control is not limited to PID control.

[Action and effect]
Since the control device for the continuously variable transmission according to the present embodiment is configured as described above, the secondary pressure is controlled by the feedback control based on the secondary pressure target value Psec_t and the secondary actual pressure Psec, and a predetermined thrust is obtained. Is secured, and the primary pressure is controlled by the feedback control based on the deviation (Rt-Rr) between the target gear ratio Rt and the actual gear ratio Rr, and a predetermined differential thrust is secured to perform the shift.

In particular, the control gain Κ of the feedback control related to the shift is calculated based on the shift command speed, the hydraulic command value, and the front-rear pressure difference of the hydraulic control valve, and when the hydraulic response sensitivity ω is large, the control gain Κ If the hydraulic response sensitivity ω is small, the control gain Κ is also set small, which causes control problems such as ensuring control responsiveness and control overshoot when the hydraulic response sensitivity ω is high, such as at high flow rates. Control stability can be ensured when the hydraulic response sensitivity ω is low, such as when the flow rate is low. As a result, shifting can be performed stably, smoothly and quickly.

Further, in the present embodiment, since the hydraulic response sensitivity ω is obtained using three of the four parameters, it is possible to avoid that the calculation configuration becomes complicated and it becomes difficult to predict the operation and manage the constants. ..

Further, in the present embodiment, since the control gain Κ is switched between two stages of high and low based on the hydraulic response sensitivity ω, the change of the control gain Κ is simplified and the control caused by the change of the control gain Κ is performed. Instability can be avoided. That is, frequent changes in the control gain Κ may lead to non-linearity of control. If the control gain Κ is changed steplessly based on the hydraulic response sensitivity ω, the control becomes non-linear. Therefore, in order to prevent the non-linearity of the control, it is preferable to change the control gain Κ stepwise based on the hydraulic response sensitivity ω, and it is particularly preferable to suppress the step stepwise to two to three steps.

[others]
In the present invention, any two of the four parameters may be used, any three parameters may be used, or all four parameters may be used.
Further, in the above embodiment, the gear ratio is directly used as the control parameter, the target value of the control parameter is the target gear ratio Rt, and the actual value of the control parameter is the actual gear ratio Rr. Any value that correlates with the gear ratio may be used.

Claims (5)

A control device for a hydraulic continuously variable transmission having a primary pulley and a secondary pulley, and a belt wound around the primary pulley and the secondary pulley.
By feedback-controlling the hydraulic control valve based on the deviation between the target value of the control parameter and the actual value of the control parameter and the control gain, the hydraulic pressure of the hydraulic oil in the oil chamber of the primary pulley or the secondary pulley is controlled. A control means that controls the shift so that the gear ratio becomes the target gear ratio,
A plurality of hydraulic responses including a shift command speed for changing the gear ratio to the target gear ratio, a hydraulic command value which is a command value of the hydraulic pressure, a front-rear pressure difference of the hydraulic control valve, and a volume of the oil chamber. A gain changing means for calculating the hydraulic response sensitivity based on at least two of the related parameters and changing the control gain based on the calculated hydraulic response sensitivity is provided.
Control device for continuously variable transmission. The gain changing means has the hydraulic response sensitivity based on three of four hydraulic response-related parameters of the shift command speed, the hydraulic command value, the front-rear pressure difference, and the volume of the oil chamber. To calculate,
The control device for a continuously variable transmission according to claim 1. The gain changing means changes the control gain stepwise based on the hydraulic response sensitivity.
The control device for a continuously variable transmission according to claim 1 or 2. The gain changing means changes the control gain in two stages based on the hydraulic response sensitivity.
The control device for a continuously variable transmission according to claim 3. The control means performs the shift control by performing the feedback control on the primary pulley.
The gain changing means is based on the characteristics of three hydraulic response-related parameters, that is, the shift command speed, the hydraulic command value, and the front-rear pressure difference, assuming that the volume of the oil chamber of the primary pulley is maximum. To calculate the hydraulic response sensitivity.
The control device for a continuously variable transmission according to any one of claims 1 to 4.

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