JP3277852B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a continuously variable transmission, and more particularly to a shift speed control for a V-belt type continuously variable transmission.

[0002]

2. Description of the Related Art As a shift control device of a continuously variable transmission mounted on a vehicle, a V-belt type shift control device has been conventionally known. For example, Japanese Patent Application Laid-Open No. 61-105 proposed by the present applicant.
No. 353, for example.

As shown in FIG. 9, a pair of variable pulleys 16 and 26 on a primary side and a secondary side whose contact pulley width with a V-belt 24 of a continuously variable transmission is variably controlled based on hydraulic pressure. By changing the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16, the movable conical plate 22 facing the fixed conical plate 18 is driven in the axial direction to continuously change the gear ratio of the continuously variable transmission. Things.

The cylinder chamber 20 for driving the movable conical plate 22 of the primary pulley 16 communicates with a speed change control valve 63 driven by a step motor 64 via a speed change link 67. While the other end is connected to the motor 64, the other end is axially engaged with the movable conical plate 22 of the primary pulley 16, and the middle of both ends is connected to the shift control valve 63.

The stepping motor 64 drives the transmission link 67 in accordance with a target transmission ratio from a CVT control unit (not shown), while the other end of the transmission link 67 is in accordance with the position of the movable conical plate 22, that is, the actual transmission ratio. Since the shift control valve 63 is displaced, the shift control valve 63 is driven in accordance with the difference between the actual speed ratio and the target speed ratio, and the speed change link 67 mainly constitutes feedback means.

In such a shift control of the primary pulley 16 by the shift link 67, the gear ratio continuously changes from the lowest Lo to the highest Hi in accordance with an increase in the drive amount of the step motor 64, but at the time of starting, the primary gear is changed. Since the hydraulic pressure of the cylinder chamber 20 of the pulley 16 rises from 0, as shown in FIG. 10, when the vehicle starts from time 0 with the throttle opening TVO = 1/8, the shift start point A shown in FIG.
, The shift to the Hi side is started, and the hydraulic pressure of the primary pulley cylinder chamber 20 starts to increase from this time ta, and a delay occurs until the predetermined balance pressure is reached and the shift is actually performed, tb. As shown by the broken line in FIG. 11, the primary rotational speed Npri exceeds the point A, which is the shift start position, and once increases and then decreases to a predetermined rotational speed, and the engine rotational speed (= primary rotational speed Npri) In some cases, a shock was generated due to the excessive upswing of (2), and the drivability and riding comfort were sometimes reduced.

Therefore, the applicant of the present invention has filed Japanese Patent Application No. 8-1443.
44, the actual gear ratio is a predetermined maximum L
The shift is started from the position o. For a predetermined time after the start of the vehicle is detected, the target gear ratio is shifted up to the predetermined Hi side from the maximum Lo, so that the shift is started before the shift is started. It has been proposed that the hydraulic pressure in the primary pulley cylinder chamber 20 reach a predetermined balance pressure, feedback is performed immediately after starting, and an excessive increase in the engine speed at the time of starting is prevented.

[0008]

However, in the above-described conventional example, as shown in FIG. 11, in the automatic transmission mode of the continuously variable transmission, the automatic transmission mode depends on the throttle opening TVO (or the amount of depression of the accelerator pedal). The vehicle speed VSP at which the shift is started from the lowest Lo gear ratio is different, and when the target gear ratio to be up-shifted to the Hi side from the lowest Lo in advance at start is small (Hi side), the throttle opening TVO is large. In some cases, when the target gear ratio is large (Lo side), the engine speed is excessively increased when the throttle opening TVO is small, as in the conventional example. There was a problem.

The present invention has been made in view of the above problems, and suppresses an excessive increase in the engine speed regardless of the amount of depression of an accelerator pedal, and performs feedback control of a speed ratio immediately after starting. The purpose is to balance both.

[0010]

According to a first aspect of the present invention, there is provided a pair of primary and secondary variable pulleys in which a contact belt width of a V-belt is variably controlled based on hydraulic pressure, and a secondary side is connected to a drive shaft. A continuously variable transmission, and target speed ratio setting means for setting a target speed ratio of the continuously variable transmission in accordance with a driving state of the vehicle or a command from a driver,
A shift control valve for supplying hydraulic pressure to the variable pulley, an actuator for driving the shift control valve in accordance with the target gear ratio, and an actual gear ratio of the continuously variable transmission when the vehicle is stopped is changed by a maximum Lo.
A feedback means for controlling the shift control valve so as to attain the speed ratio and correcting the shift control valve so as to be equal to the target speed ratio during running, and at the time of starting from a stopped state , setting the target speed ratio to the lowest Lo speed shift. A shift control device for a continuously variable transmission, the shift control device comprising: a shift start correcting unit that shifts to a Hi side from a ratio; the shift start correcting unit detects an opening degree of an accelerator pedal; Shift amount changing means for increasing the shift amount to the Hi side as the stepping amount of the pedal is smaller.

According to a second aspect of the present invention, in the first aspect, the shift amount changing means is configured to shift to the Hi side.
The amount is set according to the limit value of the maximum Lo speed ratio.

[0012] In a third aspect based on the second aspect, the limit value of the maximum Lo speed ratio is determined by setting a maximum value of an accelerator pedal.
It is set according to the amount of depression and the accelerator pedal is depressed.
Even if the intrusion amount becomes the maximum, it is set to the Hi side by a predetermined amount from the maximum speed ratio that can be set in the continuously variable transmission.

In a fourth aspect based on the first aspect, the target speed ratio setting means includes an automatic speed change mode and a manual mode, and the speed change start correction means has a maximum Lo when the manual mode is selected. The gear is shifted to the Hi side by a predetermined amount from the gear ratio.

In a fifth aspect based on the first aspect, the shift start correction means sets the maximum Lo speed ratio in accordance with a tolerance of the maximum Lo speed ratio that can be set in the continuously variable transmission during normal control. Shift to the Hi side.

[0015]

Therefore, according to the first aspect of the present invention, a pair of variable pulleys for sandwiching the V-belt are provided with a target speed ratio according to a driving state such as a vehicle speed and an accelerator pedal opening or a command from a driver. The speed change control valve is driven by feedback means so that the drive amount of the actuator according to the target speed ratio and the actual speed ratio of the continuously variable transmission match when the speed ratio is changed. The shift amount from the lowest Lo gear ratio to the Hi side is changed based on the depression amount of the accelerator pedal, and in particular, the depression amount of the accelerator pedal is small.
In short, the shift amount to the Hi side is increased. For this reason,
As the amount of depression increases, the maximum L that can be set in the continuously variable transmission
o While the gear ratio is set to the gear ratio side, the smaller the stepping amount is, the higher the setting is to the Hi side. If the stepping amount is large, there is a margin in the time from the start of the start to the start of the shift, so The hydraulic pressure can be sufficiently increased to a predetermined oil pressure, and hunting of the gear ratio caused by setting the maximum Lo gear ratio to the Hi side too much is prevented. On the other hand, when the depression amount is small, the time from the start to the start of the gear shift is short. By setting the gear ratio to Hi than the maximum Lo gear ratio, the oil pressure on the primary pulley side can be increased to a predetermined oil pressure in advance, and the feedback control can be quickly performed. It is possible to quickly perform feedback control of the gear ratio immediately after the start, while suppressing an excessive increase in the engine speed as in the conventional example. It from becoming possible to improve the shift control accuracy.

The second invention is directed to a shift amount to the Hi side.
Is set according to the limit value of the maximum Lo speed ratio, so that the Hi side
To prevent hunting of the gear ratio caused by setting
On the other hand, if the accelerator pedal is
Since the time from starting to shifting to the start of shifting is short, the maximum Lo limit value
Feedback control quickly by setting to the Hi side
It is possible to shift to the accelerator pedal
Regardless of the size of the embedded
Thus, it is possible to quickly perform the feedback control of the speed ratio immediately after the vehicle starts , while suppressing an excessive increase in the engine speed, thereby improving the accuracy of the speed change control of the continuously variable transmission.

According to the third aspect of the invention, when the amount of depression of the accelerator pedal is large, there is enough time from the start to the start of shifting, so that the hydraulic pressure of the primary pulley is sufficiently increased to a predetermined balance pressure. This prevents hunting of the pulley ratio caused by setting the maximum Lo speed ratio too high on the Hi side. Note that even when the depression amount of the accelerator pedal at which the target gear ratio becomes the largest is the largest, the maximum Lo limit value is set to the Hi side by a predetermined amount from the maximum gear ratio that can be set in the continuously variable transmission, and the feedback control is performed. Can be smoothly performed.

Further, in the fourth invention, in the manual mode, a unique value can be set for the shift amount on the Hi side,
In the automatic shift mode and the manual mode, different Hi-side shift amounts can be set, and control according to the shift mode can be performed.

Further, in the fifth invention, during normal control, the maximum Lo is set according to the tolerance of the maximum Lo speed ratio that can be set in the continuously variable transmission.
Since the gear ratio is shifted to the Hi side, errors in the maximum Lo gear ratio due to dimensional tolerances of components and tolerances during assembly can be absorbed, and the quality of a vehicle with a continuously variable transmission can be improved. You can.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 8 show an embodiment of the present invention.
FIG. 1 is a schematic configuration diagram of a shift control device of a V-belt type continuously variable transmission, and FIG.
Are respectively shown.

In FIG. 1, a continuously variable transmission 17 includes a primary pulley 16 connected to an engine (not shown) as a pair of variable pulleys, and a secondary pulley 26 connected to a drive shaft. Belt 2
4 are connected.

Then, the gear ratio of the continuously variable transmission 17 (hereinafter referred to as the gear ratio)
The contact frictional force of the V-belt 24 is controlled by a hydraulic control valve 3. The hydraulic control valve 3 has a line pressure control means (not shown) for adjusting the line pressure, and a CVT control as shown in FIG. The shift control valve 63 according to the target pulley ratio from the unit 1
Motor 64 as an actuator for driving
Will be installed.

The CVT control unit 1 includes a primary pulley rotation speed sensor 6 for detecting the rotation speed Npri of the primary pulley 16 of the continuously variable transmission 17 and a secondary pulley rotation speed sensor 7 for detecting the rotation speed Nsec of the secondary pulley 26. The signal, the shift mode Mode and the select position from the inhibitor switch 8, and the throttle opening TVO (or the accelerator pedal depression amount) from the throttle opening sensor 5 according to the accelerator pedal depression amount operated by the driver. The oil temperature Tf and the vehicle speed VS of the continuously variable transmission 17 are read from a temperature sensor (not shown).
By reading P, the pulley ratio ip is variably controlled according to the driving state of the vehicle or the driver's request. In this embodiment, a value obtained by multiplying the secondary rotation speed Nsec by a predetermined constant is read as the vehicle speed VSP.

As shown in FIG. 3, in addition to the automatic shift mode, the inhibitor switch 8
An up switch 81 for instructing an upshift by an operation of 0 and a down switch 82 for instructing a downshift
And a manual mode that can be set to an arbitrary gear position is provided.

The V-belt type continuously variable transmission 17 has a torque converter 12 having a lock-up clutch 11 interposed between it and an engine (not shown). The output of the torque converter 12 is a primary pulley 16 as an input shaft. Is transmitted to

The primary pulley 16 has a fixed conical plate 18 which rotates integrally, and is arranged opposite to the fixed conical plate 18 to form a V-shaped pulley groove. It is composed of a movable conical plate 22 that can be displaced in the axial direction by a primary pulley hydraulic pressure).

On the other hand, the secondary pulley 26 is connected to the axle side, and has a fixed conical plate 30 which rotates coaxially and integrally with the secondary pulley 26;
A movable conical plate 3 which is disposed opposite to and forms a V-shaped pulley groove, and which can be displaced in the axial direction according to the hydraulic pressure (line pressure) acting on the secondary pulley cylinder chamber 32.
4

The movable conical plate 22 of the primary pulley 16 and the movable conical plate 34 of the secondary pulley 26 are displaced in the axial direction to change the contact radius with the V-belt 24 so that the primary pulley 16 and the secondary pulley 26 The pulley ratio, ie, the pulley ratio ip, can be changed.

For example, if the width of the V-shaped pulley groove of the primary pulley 16 is increased, the V
Since the contact radius of the belt 24 becomes large, a large pulley ratio (the gear ratio is on the Low side) can be obtained. If the movable conical plates 22 and 34 are displaced in the opposite direction, the pulley ratio becomes smaller (the gear ratio becomes Hi).

The shift control for changing the widths of the V-shaped pulley grooves of the primary pulley 16 and the secondary pulley 26 is performed by hydraulic pressure control to the primary pulley cylinder chamber 20, and as shown in FIG. This is performed by controlling a step motor 64 that drives a shift control valve 63 of the control valve 3.

The step motor 64 drives the transmission control valve 63 in response to a command from the CVT controller 1 via the transmission link 67, and adjusts the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16 to thereby control the actual pulley. Ratio Aip
Is controlled to match the target pulley ratio ip.

The feedback means mainly composed of the hydraulic control valve 3 and the transmission link 64 is constructed in the same manner as in the prior art, and the step motor 64 is connected to the pinion 6.
6 and the rack 65 meshes with each other.
Is connected to one end of a transmission link 67 having a predetermined lever ratio. A spool of the transmission control valve 63 is connected to the middle of the transmission link 67, and a feedback member 158 responsive to the axial displacement of the movable conical plate 22 is connected to the other end of the link 67.

One end of the feedback member 158 is axially engaged with the outer periphery of the movable conical plate 22, and the rod 60a of the line pressure control valve 60 is connected to a predetermined position. The shift control valve 63 and the line pressure control valve 60 are driven in accordance with the displacement of the movable conical plate 22 that becomes the actual pulley ratio.

The shift control valve 63 controls the hydraulic pressure supplied to the cylinder chamber 20 of the primary pulley 16 in accordance with the drive amount (rotational position) of the step motor 64 in the same manner as in FIG. By primary pulley 1
The shift is performed by increasing or decreasing the hydraulic pressure supplied to the cylinder chamber 20 of No. 6.

In FIG. 2, 78 is a manual valve responsive to the shift lever, 76 is a negative pressure diaphragm, 7
7 is a throttle valve which responds to the negative pressure diaphragm 76,
95 is the lowest Low pulley ratio (the lowest Lo speed ratio)
There is a Lo switch that turns on when displaced to.

Next, an example of the shift control performed by the CVT control unit 1 will be described in detail with reference to flowcharts of FIGS. 4 to 6 and a control conceptual diagram of FIG. 4 shows a main routine of the shift control, FIG. 5 shows a subroutine of the servo control process, and FIG. 6 shows a subroutine of the control at the start of the shift.

In step S1, the continuously variable transmission 17 outputs the primary rotational speed Npri and the secondary rotational speed Nsec.
(= Vehicle speed VSP), the throttle opening TVO according to the driver's operation, and the oil temperature Tf of the continuously variable transmission 17, and in addition, a signal from the inhibitor switch 8 (for example, a shift mode Mode) is read. .

In step S2, if the automatic shift mode is set, the primary pulley 16 is set in accordance with the throttle opening TVO and the vehicle speed VSP based on the shift map shown in FIG.
Is calculated, ie, the target pulley ratio ip. This step S2 corresponds to the target Npri calculation unit 50 in the control block diagram of FIG.

In step S3, the time constant of the step motor 64 according to the current operation mode such as acceleration / deceleration is calculated, and in step S4, the servo of the step motor 64 is calculated from the target pulley ratio ip and the target time constant. Perform control. These steps S3 and S4 are performed by the servo controller 5 shown in FIG.
Equivalent to 3.

Next, the servo control process in step S4 is configured as shown in FIG. 5. First, in step S40, it is determined whether or not the current operation state is in the feedback control region. For example, when the oil temperature Tf is less than a predetermined value in a cold state, the feedback control cannot be performed accurately because the viscosity of the hydraulic oil is high, so the process proceeds to step S48.
Open loop control is performed using the target pulley ratio ip obtained in step S2 as a command value.

On the other hand, if the operation state is such that the oil temperature Tf is equal to or higher than the predetermined value, the process proceeds to step S41 and thereafter to perform servo control processing.

In step S41, the target pulley ratio i
p, smoothing of the target time constant to suppress an excessive change in the gear ratio.

In step S42, a limit value Loma of the pulley ratio on the lowest Lo side when shifting is performed at the time of starting or the like as described later.
x is obtained, and the maximum Lo pulley ratio of the target pulley ratio ip is limited by the maximum Lo limit value Lomax. This shift start control process corresponds to the Lo side limit value setting unit 51 and the limiter 52 in FIG.

Next, in step S43, compensation is performed based on the target time constant obtained in step S3 in order to compensate for the followability of the step motor 64.

Then, in step S44, feedback compensation is performed based on the difference between the actual pulley ratio Aip and the target pulley ratio ip. A ratio command value is commanded in step S47.

After obtaining the pulley ratio command value by the servo control or the open loop control in steps S47 and S48, the pulley ratio command value is converted into the angular position of the step motor 64 in step S49. And outputs a pulse corresponding to
To control the gear ratio.

The processing in steps S43 to S50 is the same as the dynamic characteristic compensation control including disturbance compensation disclosed in Japanese Patent Application Nos. 9-89494 and 9-89496 proposed by the present applicant.

Next, the details of the shift start control performed in step S42 will be described with reference to the flowchart of FIG.

First, in step S60, it is determined whether or not the current operation state is under a shift start control condition. The process proceeds to step S61 and subsequent steps only when a preset condition is satisfied. Is determined to be during normal shift control, and the process proceeds to step S64.

The shift start control condition is, for example, the case where it is determined in step S40 that the open loop control region has been changed to the feedback control region and the shift position is in a travel range other than the N range or the P range. When the shift start control condition is satisfied and the shift start control from steps S61 to S63 is performed, the target pulley ratio
When ip becomes less than the maximum Lo limit value Lomax, the shift start control ends, and the process of step S64 is performed.

When the shift start control condition is satisfied, it is determined in step S61 whether the current shift mode Mode is the automatic shift mode or the manual mode. If the shift mode is the manual mode, the process proceeds to step S62 to use the shift mode in the manual mode. The predetermined value LomaxM is set as the maximum Lo limit value. Note that the maximum Lo limit value LomaxM for the manual mode is used.
Is set to a value that can suppress deviation from the shift line even when the throttle opening TVO is small. A plurality of shift lines in the manual mode are set at a predetermined inclination between the Lo line and the Hi line in the shift map shown in FIG. 11, and each shift line is set as a shift speed.

On the other hand, in the case of the automatic shift mode, as shown in FIG. 8, the maximum Lo limit value Lomax is obtained from a map preset according to the throttle opening TVO. The map of FIG. 8 shows that the larger the throttle opening TVO is,
On the other hand, it is set to the lowest Lo pulley ratio side that can be set by the continuously variable transmission 17, while it is set to the Hi side as the throttle opening TVO is smaller.

That is, when the throttle opening TVO is large (for example, TVO ≧ 4/8), there is room in the shift map shown in FIG. The hydraulic pressure in the chamber 20 can be sufficiently increased to a predetermined balance pressure, and hunting of the pulley ratio caused by setting the lowest Lo pulley ratio too high as described above is prevented. Note that even when the throttle opening TVO at which the target pulley ratio ip becomes the largest is fully open, the maximum Lo limit value Lomax is maintained at the continuously variable transmission 17.
Is set on the Hi side by a predetermined amount α from the lowest Lo pulley ratio (the highest Lo line in FIG. 11), and the transition to feedback control (= servo control) can be performed smoothly.

On the other hand, when the throttle opening TVO is small (for example, TVO ≦ 3/8), the time from the start of the shift to the start of the shift is short in the shift map of FIG. In addition, it is necessary to raise the hydraulic pressure of the primary pulley cylinder chamber 20 to a predetermined balance pressure in advance, and to promptly shift to the feedback control. Therefore, the smaller the throttle opening TVO, the lower the Lo limit value L
Omax is set to the Hi side.

In step S64 in the case where the shift start control is not performed, the maximum Lo limit value LomaxD for normal control is selected.
Is set slightly higher than the lowest Lo pulley ratio that can be set in the above. This is because if the design value of the lowest Lo pulley ratio of the continuously variable transmission 17 is, for example, 2.00, it is manufactured in the range of 1.99 to 2.01 depending on the dimensional tolerance of each part and the tolerance at the time of assembly. Will be. 1. The actual maximum Lo pulley ratio is 2.
01, the command value cannot be realized when the maximum Lo pulley ratio of 2.00, which is the design value, is 2.00. Therefore, the feedback compensation amount in step S44 and the disturbance in step S45. A deviation may be added to the compensation amount or the like, and the accuracy of the shift control may decrease.

For this reason, by setting the maximum Lo limit value LomaxD during normal control to a value slightly higher than the maximum Lo pulley ratio that can be set in the continuously variable transmission 17 in accordance with the above-mentioned tolerance, an accurate speed change is always achieved. Control can be performed.

Thus, at the time of shift start control, step S
At 62 and S63, the maximum Lo limit value Loma according to the shift mode
On the other hand, x is set, and at the time of the normal control in which the shift start control is completed, the maximum Lo limit value LomaxD according to the tolerance is selected, and the process proceeds to step S65.

In step S65, the above-mentioned maximum Lo limit value L
The smaller of omax and the target pulley ratio ip calculated in step S2, that is, the pulley ratio on the Hi side, is output as the control target value.

According to the above control, when the vehicle is started in the automatic transmission mode, the set target pulley ratio ip becomes the maximum that can be set by the continuously variable transmission 17 as the throttle opening TVO increases as shown in the map of FIG. While set on the Lo pulley ratio side,
The smaller the throttle opening TVO is, the higher it is set to Hi side,
When the throttle opening TVO is large (for example, TVO ≧
4/8), there is a margin in the time from the start to the start of shifting, so that the hydraulic pressure of the primary pulley cylinder chamber 20 can be sufficiently increased to a predetermined balance pressure, and the lowest Lo pulley ratio is set to the highest Lo limit value Lomax. By setting the lowest Lo side set in the above, hunting of the pulley ratio caused by setting too high on the Hi side is prevented. On the other hand, when the throttle opening TVO is small (for example, TVO ≦ 3/8), the vehicle is started from the start. Since the time until the shift is started is short, the Hi-side maximum Lo limit value Loma
By setting to x, it is possible to raise the hydraulic pressure of the primary pulley cylinder chamber 20 to a predetermined balance pressure in advance, and quickly shift to feedback control, regardless of the magnitude of the throttle opening TVO. Improving the accuracy of speed change control of a continuously variable transmission by enabling quick feedback control of the speed ratio immediately after starting while suppressing an excessive increase in the engine speed as in the conventional example. It becomes possible.

When a manual mode is provided, the maximum Lo limit value LomaxM unique to the manual mode can be set separately from the automatic shift mode, so that smooth start control is always performed regardless of the shift mode. In addition, it is possible to improve the drivability of a vehicle with a continuously variable transmission that can switch between a manual mode and an automatic transmission mode.

At the time of normal shift control, the maximum Lo limit value LomaxD is set slightly higher than the maximum Lo pulley ratio that can be set by the continuously variable transmission 17, so that the dimensional tolerance of each part and the assembly time can be reduced. An error in the lowest Lo pulley ratio due to a tolerance or the like can be absorbed, and the quality of the vehicle with a continuously variable transmission can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a continuously variable transmission showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of a hydraulic control valve.

FIG. 3 is a schematic diagram of a shift gate.

FIG. 4 is a flowchart illustrating an example of a gear ratio control performed by a CVT control unit, and illustrates a main routine.

FIG. 5 also shows a subroutine of servo control.

FIG. 6 shows a subroutine of control at the start of gear shifting.

FIG. 7 is a control conceptual diagram of shift control.

FIG. 8 is a map of a Lo side limit value in the automatic transmission mode, showing a relationship between a throttle opening TVO and a pulley ratio ip.

FIG. 9 is a schematic diagram of a shift control device of the V-belt type continuously variable transmission.

FIG. 10 shows the primary pulley cylinder chamber oil pressure P at the time of starting.
Shows the relationship between pri and time t.

FIG. 11 is a shift map in an automatic shift mode, showing a relationship between a vehicle speed VSP and a primary rotation speed Npri using a throttle opening TVO as a parameter.

[Explanation of symbols]

 Reference Signs List 1 CVT control unit 6 Primary rotation speed sensor 7 Secondary rotation speed sensor 16 Primary pulley 17 Continuously variable transmission 20 Primary pulley cylinder chamber 24 V belt 26 Secondary pulley 51 Maximum Lo limit value setting unit 52 Limiter 63 Transmission control valve 64 Step motor 67 Transmission link

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 F16H 9 / 00

Claims (5)

(57) [Claims] 1. A continuously variable transmission having a pair of primary and secondary variable pulleys whose contact belt pulley width of a V-belt is variably controlled based on oil pressure and having a secondary side coupled to a drive shaft; Target gear ratio setting means for setting a target gear ratio of the continuously variable transmission in accordance with a state or a command from a driver; a gear control valve for supplying oil pressure to the variable pulley; and a gear shift according to the target gear ratio The actual gear ratio of the continuously variable transmission when the vehicle is stopped is the lowest Lo gear ratio.
Feedback control means for controlling the speed change control valve so that the speed change control valve becomes equal to the target speed change ratio during running, and when starting from a stopped state , the target speed change ratio is set to be smaller than the maximum Lo speed ratio. A shift control device for a continuously variable transmission, comprising: a shift start correcting unit that shifts to a Hi side; wherein the shift start correcting unit detects an opening degree of an accelerator pedal, and an amount of depression of the accelerator pedal. A shift control device for a continuously variable transmission, comprising: a shift amount changing unit that increases a shift amount to the Hi side as the value of the gear ratio is smaller. 2. The shift amount changing means according to claim 1, wherein
The shift control device for a continuously variable transmission according to claim 1, wherein the shift amount is set in accordance with a limit value of a maximum Lo speed ratio . 3. The accelerator system according to claim 1, wherein the limit value of the lowest Lo speed ratio is an accelerator pedal.
The accelerator pedal is set according to the amount of depression of the
Can be set with a continuously variable transmission even if the stepping amount of the
3. The shift control device for a continuously variable transmission according to claim 2, wherein a predetermined amount is set on the Hi side from a maximum gear ratio . 4. The target speed ratio setting means includes an automatic speed change mode and a manual mode, and the shift start correction means shifts a predetermined amount to the Hi side from the lowest Lo speed ratio when the manual mode is selected. The shift control device for a continuously variable transmission according to claim 1, wherein: 5. The shift start correcting means shifts the maximum Lo speed ratio to the Hi side according to a tolerance of the maximum Lo speed ratio that can be set in the continuously variable transmission during normal control. 3. The shift control device for a continuously variable transmission according to claim 1.