JP3488937B2 - Control device for toroidal type 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 improved control device for a toroidal type continuously variable transmission.

[0002]

2. Description of the Related Art In a toroidal type transmission used in a vehicle, forward / reverse switching means is provided on the input side of the transmission in order to promote miniaturization of the vehicle, and before the torque is amplified by the transmission, By changing the rotation direction according to forward and backward movement, the forward and backward movement switching means can be made smaller and lighter. As such a toroidal type continuously variable transmission, Japanese Patent Application Laid-Open No. 2-16
3562, Japanese Patent Laid-Open No. 4-78366, etc. are known.

As shown in FIGS. 11 to 13, these continuously variable transmissions include a torque converter 12 connected to an engine.
A forward / reverse switching device 40 is interposed between the toroidal type continuously variable transmission 10 and the rotation direction of the input shaft 16 of the toroidal type continuously variable transmission 10.

The toroidal type continuously variable transmission 10 is composed of a first toroidal transmission unit 18 and a second toroidal transmission unit 20 of a half toroidal type and is provided with two sets of input / output disks 18a, 18b and 20a, 20b. Indicates
As shown in FIG. 12, the pair of power rollers 18c and 18d sandwiched between the input disk 18a and the output disk 18b of the first toroidal speed change unit 18 are axially supported by offset rotary shafts 50b and 52b. Rotating shaft 50
The trunnion shafts 50a and 52a, which drive the b and 52b in the vertical direction in the figure and allow rotation around the shafts, are driven by the actuators 50 and 52.
the power roller 18 according to the vertical displacement of a and 52a.
The gear ratio is changed by changing the inclination angles of c and 18d.

The actuator 50 is a trunnion shaft 50a.
Oil chamber 50L for driving to ascend and oil chamber 50H for driving to descend
While the vehicle is moving forward, the gear ratio increases and changes to the Low side when the trunnion shaft 50a rises, while the gear ratio decreases and changes to the Hi side when the trunnion shaft 50a descends. The gear ratio is increased by decreasing 52a, while the gear ratio is decreased by increasing, so that the actuators 50 and 52 cause oil chambers 50H and 52H to shift to the Hi side and oil chambers 50L and 5H to shift to the Low side.
2L are communicated with each other to control the inclination angles of the power rollers 18c and 18d synchronously. The second toroidal transmission unit 20 has the same structure.

In such a toroidal type continuously variable transmission,
A rotary shaft 50b for supporting the power rollers 18c, 18d,
Since 52b is offset, when the rotation direction of the input shaft 16 changes, the gear shift direction reverses. That is, when the vehicle is in reverse, the gear ratio decreases as the trunnion shaft 50a rises, and H
While being shifted to the i side, the gear ratio is increased due to the downward movement and is shifted to the Low side.

Therefore, a first control valve 60 for controlling the speed ratio when moving forward and a second control valve for controlling the speed ratio when moving backward are provided in order to switch the speed changing direction according to the forward and backward movement of the vehicle. Switching valve 80 for selectively switching these control valves according to forward and backward movement
And the spool 82 of this switching valve 80 is
As shown in FIG. 13, the one-way clutch 92 that detects forward and backward movement of the vehicle is driven by the claw 94a of the bush collar 94 that swings in accordance with the rotation direction of the output shaft 30 of the transmission, and the one-way clutch is used when moving forward. 92 becomes free and the claw 94a does not press the spool 82, and the switching valve 8
No. 0 supplies the hydraulic pressure from the first control valve 60 to the actuators 50 and 52, while the pawl 94a is used during reverse travel.
Presses the spool 82 and the switching valve 80 supplies the hydraulic pressure from the second control valve 70 to switch the speed changing direction of the power rollers 18c and 18d in accordance with the forward and backward movement. The first and second control valves 60,
The hydraulic pressure from 70 is determined according to the displacement amount of the spools 63 and 73 driven by the step motors 61 and 71.

[0008]

However, in the toroidal type continuously variable transmission as described above, the claw 94a that swings in accordance with the forward and backward movement is repeatedly contacted with and separated from the spool 82, so that it is damaged due to deterioration with time or the like. In such a case, the switching valve 80 does not operate, is held in the forward movement position, and is shifted by the step motor 61 that drives the first control valve 60 on the forward movement side. When the shift control in the reverse direction of the vehicle is performed with the switching valve 80 in the forward position, the shift characteristic of the toroidal-type continuously variable transmission 10 is different from the normal characteristic shown by the solid line in FIG. As shown by the alternate long and short dash line, the rotation is reversed and, for example, the step motor 61 is held at lowstp in the figure, and the hydraulic pressure from the first control valve 60 is lowered to the maximum speed ratio
Even if it is held at the point A ₀ on the _max side, the power rollers 18c, 18
d is A ₀ 'in the figure due to the reverse rotation of the I / O disk to the reverse side
15, the vehicle speed VS is increased even if the throttle opening TVO increases as shown in FIG.
There was a case where P did not increase and it was not possible to start smoothly.

In the toroidal type continuously variable transmission, the rotary shaft 50 that supports the power rollers 18c and 18d.
Since b and 52b are bent to offset the power roller and the swing shaft, elastic deformation or the like occurs in the bent rotary shafts due to the fluctuation of the input torque, and the inclination angle of the power roller, that is, the gear ratio. Changes, that is, a so-called torque shift occurs. As shown in FIG. 16, this torque shift changes according to the gear ratio and the input torque, and when the gear ratio R is set in the figure, the inclination angle of the power roller decreases as the input torque increases. , The gear ratio fluctuates toward R ′ on the low side, and there are cases where the desired gear ratio cannot be obtained due to deviation of the inclination angle of the power roller corresponding to the position of the spool of the control valve. It is necessary to correct the shift of the ratio. Now, in FIG. 14, it is attempted to drive the spool to the lowstp position corresponding to the maximum gear ratio low _max at the time of starting to obtain the maximum gear ratio at point A in the figure. However, if the actual gear ratio deviates to B in the figure due to the increase in input torque, the spool is set to low.
Even if it is further displaced from stp to the low side (the direction in which the displacement amount is small), point A ₀ is at the maximum physically shiftable value and the gear ratio does not change any more. It may not be possible to correct the gear ratio to low _max .
Similarly, there is a problem that the target value cannot be corrected even when the gear ratio deviates near the minimum gear ratio hi _max .

Therefore, the present invention has been made in view of the above problems, and the vehicle can be smoothly started even in the event of a failure such that the speed change direction of the power roller cannot be switched according to the forward or backward movement of the vehicle. An object of the present invention is to provide a toroidal type continuously variable transmission capable of surely correcting a shift in gear ratio.

[0011]

As shown in FIG. 17, a first aspect of the present invention relates to a gear ratio changing means 220 in which the control direction of the gear ratio is different depending on the forward / backward movement of the vehicle, and to the forward / backward movement of the vehicle. Forward / reverse switching means 21 for switching the control direction of the gear ratio
0 and a control unit 200 that calculates a target gear ratio RTO according to the operating state of the vehicle and controls the gear ratio changing unit 220. A predetermined torque shift from the maximum value RNGL _max of the gear ratio that can be set by the means 220.
Comprising a first target gear ratio regulating means 201 for regulating the maximum value RTOL _max of the target speed ratio correction amounts only a small becomes a value deviation of the gear ratio corresponding.

The second aspect of the present invention is, as shown in FIG. 17, a gear ratio changing means 220 in which the control direction of the gear ratio is different according to the forward / backward movement of the vehicle, and the gear ratio change means 220 according to the forward / backward movement of the vehicle. Forward / backward switching means 210 for switching the control direction, and control means 2 for calculating the target gear ratio RTO according to the driving state of the vehicle and controlling the gear ratio changing means 220.
In the control device for a toroidal type continuously variable transmission including No. 00 , the gear ratio according to the torque shift is greater than the maximum gear ratio RNGL _max that can be set by the gear ratio changing unit 220.
Minimum RNGH the first target gear ratio regulating means 201 for regulating the maximum value RTOL _max of the target speed ratio correction amounts only a small consisting value deviation, the settable transmission ratio by the gear ratio changing means 220 A change depending on the torque shift rather than _max.
The second target gear ratio regulating means 202 is provided to regulate the minimum value RTOH _max of the target gear ratio to a value large enough to correct the deviation of the speed ratio .

[0013]

Therefore, the first aspect of the present invention is directed to the target gear ratio RTO.
The maximum value RTOL _max of the
Maximum gear ratio RNGL _{max that} can be set by the gear ratio changing means
The gear ratio is set to be smaller by a predetermined amount than the above, and the gear shift control is started from this maximum target gear ratio RTOL _max . If the forward / reverse switching means does not operate due to a failure or the like, and the vehicle is moved backward with the forward gear ratio, the gear ratio shifts from the low side having a large value to the Hi side, but the maximum target gear ratio RTOL _max for starting the gear shift control. Is set to the hi side which is smaller by a predetermined amount, the gear ratio is set to a larger amount by a predetermined amount when the vehicle is traveling in reverse with the gear ratio on the forward side, and even if the forward / reverse switching means should fail, the vehicle will start smoothly to the reverse side. Furthermore, even if the actual gear ratio deviates to the side smaller than the maximum gear ratio RTOL _max due to torque shift when maintaining the maximum target gear ratio RTOR _max during acceleration, the gear ratio changing unit further by changing the gear ratio toward a maximum value RNGL _max side of settable transmission ratio, it can be reliably corrected actual speed ratio to match the maximum target speed ratio RTOL _max and torque shift .

According to the second aspect of the invention, in addition to the first gear ratio regulating means for regulating the maximum value of the target gear ratio to the maximum target gear ratio RTOL _max , the minimum value of the gear ratio which can be set by the gear ratio changing means. Since the second gear ratio regulating means for regulating the minimum value RTOH _max of the target gear ratio RTO to a value larger than the RNGH _max by a predetermined amount is provided, the target gear ratio RTO is the maximum target gear ratio RTOR _max and the minimum target gear ratio RTOH _max. And the minimum target gear ratio RTOH _max during deceleration.
Even if a torque shift occurs while maintaining the gear ratio and the actual gear ratio deviates to a side larger than the maximum gear ratio RTOH _max , the gear ratio changing means can further set the minimum gear ratio value RNGH.
By changing the gear ratio toward the _max side, the actual gear ratio can be matched with the minimum target gear ratio RTOH _max , and the torque shift can be reliably corrected.

[0015]

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

As shown in FIG. 1, in the continuously variable transmission 1, a forward / reverse switching device 40 is provided between the toroidal type continuously variable transmission 10 and the torque converter 12 as in FIGS. 11 to 13 of the conventional example. It is interposed and driven by the hydraulic control device 4 supplied with hydraulic pressure from the hydraulic pump 84.

This hydraulic control device 4 is constructed in substantially the same manner as the conventional example shown in FIGS. 12 and 13, and has first and second gear ratio changing means for controlling the gear ratios when the vehicle is moving forward and backward. Second control valves 60, 70,
A one-way clutch 92 and a claw 94 of a bushing collar 94 as means for detecting the forward / backward movement of the vehicle and switching the control direction of the gear ratio, and the first or second control valve 60 driven by the claw 94 according to the forward / backward movement. A switching valve 80 for selectively supplying hydraulic pressure to 70 is mainly configured.

Here, as shown in FIG. 2, the first and second control valves 60 and 70 are formed by integrally forming the lockup prohibiting valve 100 with the spools 63 and 73, and the spool 63 has a predetermined amount lowstop. Spool 10 that blocks ports 102 and 103 until it is displaced to
1 to stop the supply of hydraulic pressure from the hydraulic pump 84 to the lockup clutch 12d shown in FIG.
Spools 63, 73 (hereinafter simply referred to as spool)
When the displacement amount of exceeds the predetermined value lowstp, the port 10
2 and 103 are connected to each other to supply a hydraulic pressure to the lockup clutch 12d to permit the lockup operation of the torque converter 12.

The continuously variable transmission 1 is controlled by a shift control controller 2 mainly composed of a microcomputer, and the engine speed Ne and throttle opening TVO input from the engine control controller 3 and a selector from the shift lever 5 are selected. Position and toroidal continuously variable transmission 10
The input shaft rotation speed Nt and the output shaft rotation speed No are read from the input shaft rotation sensor 6 and the output shaft rotation sensor 7, respectively, and the target gear ratio R corresponding to the operating state of the vehicle is read.
Calculate TO.

Then, the shift control controller 2 drives the step motors 61 and 71 which determine the displacement amounts of the spools of the first and second control valves 60 and 70 based on the calculated target gear ratio RTO, and the toroidal type. The inclination angle of the power roller of the continuously variable transmission 10 is set to a value according to the gear ratio.

An example of the control performed by the shift control controller 2 is shown in the flow charts of FIGS. 3 to 7, and will be described in detail with reference to these flow charts. It should be noted that each flow chart is executed every predetermined time, for example, every 10 msec.

FIG. 3 is for detecting the driving state of the vehicle.
In step S1, the engine speed Ne and the throttle opening T
The VO is read from the engine controller 3 and the input shaft rotation speed Nt, the output shaft rotation speed No, and the position of the shift lever 5 are read from the continuously variable transmission unit 1.

In step S2, the output shaft speed No is multiplied by the conversion constant A to obtain the vehicle speed VSP. In step S3, the preset throttle opening threshold value TVOth and the vehicle speed threshold value VSPth are set. Read.

The flowchart of FIG. 4 is based on the above step S.
The gear ratio and the control amounts of the step motors 61 and 71 are calculated according to the operating states read in 1 to 3, and in step S10, the throttle opening TVO is set to the threshold value TVO.
If it is larger than th, the routine proceeds to step S12, while if the throttle opening TVO is equal to or smaller than the threshold TVOth, the routine proceeds to step S12 on condition that the vehicle speed VSP is larger than the threshold VSPth at step S11.

In step S12 performed when the throttle opening TVO or the vehicle speed VSP is larger than the threshold value, the target gear ratio RTO of the toroidal continuously variable transmission 10 is set to a value corresponding to the operating state. Step motor 6 for driving the first and second control valves 60, 70
Feedforward control amount FFSTEP indicating the number of steps of 1 and 71 (hereinafter, simply referred to as a step motor)
Is calculated. The feedforward control amount FFST
EP is performed based on the flowchart shown in FIG. 5 described later.

Then, in step S13, step S
From the input torque Tin and the target gear ratio RTO to the toroidal type continuously variable transmission 10 obtained in FIG.
The torque shift correction amount TS for correcting the torque shift as shown in FIG.
The torque shift correction amount TSSTEP which is the number of steps of the step motor corresponding to is calculated.

In step S15, the feedforward control amount FFSTEP is added to the torque shift correction amount TSSTEP.
Is obtained to obtain a target control amount. As shown in FIG. 9, the control amount is set to a predetermined value lowst for driving the spool from the maximum gear ratio side to a position where the gear shift can be physically started.
p and a predetermined value PSTEP1 for restricting the target gear ratio RTO set in the toroidal type continuously variable transmission 10 to the maximum value RTOR _max are calculated as the target step number DSRSTP of the step motor. .

DSRSTP = FFSTEP + TSSTE
P + lowstp + PSTEP1 In FIG. 9, the maximum shiftable value RNGL, which is the maximum gear ratio that can be physically shifted by the toroidal type continuously variable transmission 10.
_max is equal to low _max shown in FIG. 14 of the conventional example, and the target gear ratio RTO on the low side set by the shift control controller 2 is set to lowstep + P for the step motor.
Since it is performed from the position driven by the number of steps set in STEP1, the maximum value RTO of the target gear ratio RTO
_max is regulated to a gear ratio corresponding to the position where the step motor is driven to the hi side of the gear ratio by a predetermined amount PSTEP1 from the maximum gear changeable value RNGL _max, and the target gear ratio RTO set in the toroidal-type continuously variable transmission 10 is set. Is a value smaller than the maximum target gear ratio RTOR _max .

On the other hand, the minimum value of the target step number DSRSTP which is the shift position on the most hi side is RNGH _max (the above-mentioned conventional example) which is the minimum value that can be physically changed by the toroidal type continuously variable transmission 10 in FIG. Hi shown in FIG.
_It is set to a value obtained by subtracting the number of steps of the step motor by a predetermined value PSTEP2 from (equal to _max ), and the target gear ratio RTO on the hi side of the toroidal type continuously variable transmission 10 is restricted to a minimum target gear ratio RTOH _max or more. Here, in order to correct the torque shift to the hi side at the minimum gear ratio RTOH _max , the number of steps of the step motor is set to have the following equation.

FFSTEP + lowstp + PSTEP
1 ≦ HISTEP−PSTEP2 where HISTEP is the number of steps corresponding to the minimum shiftable value RNGH _max .

Therefore, the minimum target gear ratio RTOH _max
Then, according to the torque shift correction amount TSSTEP, the spool can be further driven toward the shiftable minimum value RNGH _max .

In this way, after the target step number DSRSTP is calculated, in step S16, the change amount DST indicating the step number per unit time of the step motor preset according to the shift type commanded by the shift lever 5 is set.
Read P.

On the other hand, if it is determined in step S11 that both the throttle opening TVO and the vehicle speed VSP are below the threshold value, the target step number DSRSTP is 0 and the change amount DSTP per unit time is 1 in step S13.
Set to.

In step S17, the above step S1
Target step number DSR set by 5, 16 or 13
The control amount (the number of steps) ASTP of the step motor is calculated from the STP and the change amount DSTP per unit time based on the flowchart of FIG.

Next, the calculation of the feedforward control amount FFSTEP performed in step S12 will be described with reference to the flowchart of FIG.

First, in step S20, an estimation calculation of the torque Tin input to the toroidal type continuously variable transmission 10 to calculate the torque shift correction amount is performed. This input torque Tin is calculated from the engine speed Ne and the throttle opening TVO read in step S1 and the preset torque ratio t (e) of the torque converter 12. Here, the torque for inertia energy is omitted here.

Next, in step S21, the target rotational speed DSRREV of the output shaft is calculated from a map preset based on the throttle opening TVO and the vehicle speed VSP, and in step S22, this target rotational speed DSRREV is calculated.
The target speed ratio RTO is obtained by dividing by SP.

Then, in step S23, the feedforward control amount FFSTEP is calculated from the map of the control amount of the step motor preset according to the target gear ratio RTO.

Next, the calculation of the step motor control amount ASTP performed in step S17 will be described with reference to the flowchart of FIG.

First, in step S30, the control amount ASTP set in the previous processing is compared with the target step number DSRSTP set in step S15,
If the target step number DSRSTP is larger, the process proceeds to step S31 to update the control amount ASTP plus the change amount DSTP per unit time as the control amount ASTP, and in step S32, the control amount ASTP is the target step number DSRSTP. If the target step number DSRSTP is reached, the target step number DSRSTP is updated as the control amount ASTP in step S33.
As shown in, the change amount DSTP per unit time is again added in the next process, and finally the control amount ASTP is made to match the target step number DSRSTP.

On the other hand, it is determined in step S30 that the control amount A
If STP is larger than the target step number DSRSTP, the process proceeds to step S34, and the control amount ASTP minus the change amount DSTP per unit time is subtracted from the control amount AS.
It is updated as TP, and it is determined in step S35 whether or not the control amount ASTP has reached the target step number DSRSTP. If the target step number DSRSTP has been reached, the target step number DSRSTP is set in step S33.
While it is updated as P, if it has not reached, the process is terminated, and the change amount DST per unit time is again set in the next process.
Subtract P.

In this way, the set step motor control amount ASTP is output to the step motor every predetermined time such as 10 msec as shown in FIG. 7, and the spools of the first and second control valves 60 and 70 are output. Target gear ratio R
It drives toward the position corresponding to TO.

The target gear ratio RTO set by the gear shift control controller 2 is the throttle opening TVO or the vehicle speed VS.
In the region where P is larger than the threshold values TVOth and VSPth, as shown in FIG. 9, the toroidal continuously variable transmission 10 is provided.
The range of the target gear ratio set to is the maximum shiftable value RN
It is performed between the maximum target speed ratio RTOL _max and the minimum target speed ratio RTOH _max that are set to be smaller than the range between GL _max and the shiftable minimum value RNGH _max .

That is, when one of the throttle opening TVO and the vehicle speed VSP is larger than the threshold value in the determination in steps S10 and 11 shown in the flowchart of FIG. 4, the step motor is set to low in step S15.
The amount of displacement of the spool is increased according to stp + PSTEP1, and the tilt angle of the power roller of the toroidal type continuously variable transmission 10 is driven to the position indicated by point A in FIG.
TO is the maximum shiftable maximum value RNGL which is a physical maximum value
maximum target speed ratio RTOL _max of _max than a predetermined value hi side
The shift control is performed from.

On the other hand, the throttle opening TVO and the vehicle speed VSP are equal to the threshold value TVOth when the vehicle starts or runs at a very low speed.
If VSPth or less, step S13 of FIG.
Since the target step number DSRSTP is set to 0,
The gear ratio is the maximum shiftable value RNGL _{max as} shown in FIG.
The throttle opening TVO or the vehicle speed VS is set to
In the operating region where P exceeds the threshold value, the spool goes low.
Further, the shift control is performed from the maximum target gear ratio RTOL _max by further displacing PSTEP1 from stp. The threshold value TVOth of the throttle opening TVO is set to a minute value, for example, 1/32, and the threshold value VSPth of the vehicle speed VSP is also set to a minute value, for example, 1 to 2 km / h.

Here, when the shift lever 5 is in the reverse position, the forward / reverse switching means 40 shown in FIG. 11 reverses the input shaft 16 and the output shaft 30 to detect the forward / backward movement shown in FIG. As the one-way clutch 92 operates and the claw 94a of the bush collar 94 drives the switching valve 80, the toroidal type continuously variable transmission 10 as shown in FIG.
Hydraulic pressure to be supplied to the first control valve 60 to the second
Switch to control valve 70.

At this time, if the switching valve 80 does not operate due to damage to the pawl 94a that repeats contact and separation similar to the conventional example, the power roller of the toroidal type continuously variable transmission 10 is the forward control first control valve. Controlled by 60, due to the reverse rotation of the input / output shaft as in the conventional example,
The gear ratio is about to change from low to hi.

Here, the target gear ratio RTO is set in step S1.
By 5, since the shift control from the maximum speed ratio RTOL _max is performed, the maximum speed ratio RTOL _max shown in point A in FIG. 9
To A "on the shift characteristic curve at the time of failure.

The reduction ratio RTO reduced to the point A "by the reverse rotation of the power roller is the switching valve 8 in the conventional example.
From point A'when 0 did not operate, ΔR corresponding to PSTEP1 of the step motor is set to the low side,
It is possible to secure a large reduction ratio RTO as compared with the conventional example, and it is possible to perform a smooth start with a gear ratio larger by ΔR.

The manner in which the vehicle is started in the reverse direction when the forward / reverse switching means or the forward / reverse detecting means has a failure will be described with reference to FIG. 10. When the brake is released, the torque converter 12 creeps first. , The vehicle speed VSP increases, but the vehicle speed VS increases until time T _0.
Since P is less than the threshold value VSPth (1 to 2 km / h), the target step number DSRSTP of the step motor is
Since it is set to 0 in step S13, the displacement amount of the spool is 0, that is, the target gear ratio RTO becomes the maximum shiftable value RNGL _max outside the target shift range.

At time T ₀ , the accelerator pedal is depressed, the throttle opening TVO exceeds the threshold TVOth, and the vehicle speed V
When SP exceeds the threshold value VSPth, the shift control after step S12 shown in the flowchart of FIG. 4 is started.

As the shift control is started, the step motor control amount ASTP = spool displacement amount is lowstp.
From PSTEP1 to the hi side, the target gear ratio RT
Since the control of O is started from the maximum target speed ratio RTOL _max , the speed ratio can be increased by ΔL in accordance with PSTEP1 as compared with the conventional example, and even in the case of a failure such that the switching valve 80 does not operate. , The first to control the forward side
With the control valve, it is possible to smoothly perform the start to the reverse and the shift control.

Further, since the target gear ratio is set in a region smaller than the actual gear shift region, when the vehicle is decelerated, the input torque becomes negative as shown in FIG. When a torque shift to the side occurs and the maximum target gear ratio RTOR _max is maintained in FIG. 9, the engine shifts from point A to point B in the figure. Here, the torque shift correction amount TSSTEP is made negative and the spool is
If it is displaced to the owstp side, the target gear ratio RTO can be temporarily moved to the gear changeable maximum value RNGL _max side which is larger than the maximum target gear ratio RTOR _max , that is, to the A ₀ side in the figure, and the torque shift is performed. It is possible to surely correct the shift of the gear ratio due to and maintain the maximum target gear ratio RTOR _max at the point A.

On the contrary, when the vehicle is accelerating, as shown in FIG.
Since the input torque is positive, the torque to the low side is
And a minimum target gear ratio RT
OH _maxTo maintain point, shift from point C to point D in the figure
try to. Here, the torque shift correction amount TSSTE
Make P positive and move the spool to the HISTEP side.
For example, the target gear ratio RTO is temporarily the minimum target gear ratio RT
OH_maxMinimum shift value on the Hi side RNGH_maxMove to the side
Can be operated, and the shift of the gear ratio due to torque shift can be prevented.
Correct to ensure minimum target gear ratio RTOH at point C_maxTo
Can be maintained.

As described above, since the speed ratio for performing the speed change control is set to be smaller than the physically settable range, even when the switching valve 80 does not operate during reverse travel due to a failure of the forward / reverse travel detection means or the forward / reverse travel switching means. This makes it possible to smoothly start the vehicle, and moreover, it becomes possible to reliably correct the torque shift in the vicinity of the maximum and minimum values of the shift control region, so that the precision of the shift control can be improved.

[0056]

As described above, according to the first aspect of the present invention, when the forward / reverse switching means does not operate due to a failure or the like, when the reverse gear is performed at the forward gear ratio, the gear ratio is increased from the low side to the H side.
Although the gear shifts to the i side, the maximum target gear ratio RTOL _max for starting the gear shift control is set to the hi side by a predetermined amount, so when performing reverse at the forward gear ratio, the gear ratio is set to a large amount according to the predetermined amount, It is possible to reliably start the vehicle to the reverse side, ensure the drivability in the unlikely event of a failure of the forward / reverse switching means, and further maintain the maximum target gear ratio RTOL _max during acceleration. Even if a torque shift occurs at this time and the gear ratio deviates to a side smaller than the maximum target gear ratio RTOL _max , the gear ratio changing means further changes the gear ratio to the maximum settable gear ratio RNGL _max side. As a result, the torque shift can be surely corrected, and the control accuracy of the gear ratio can be improved.

The second aspect of the present invention not only regulates the target gear ratio RTO by the maximum target gear ratio RTOR _max , but also sets the minimum gear ratio RNGH _{max that} can be set by the gear ratio changing means.
A gear ratio larger than the predetermined target amount by a minimum target gear ratio RTO
Since it is regulated as H _max , even if a torque shift occurs when maintaining the minimum target gear ratio RTOH _max during deceleration and the gear ratio deviates to a side larger than the maximum target gear ratio RTOH _max , the gear ratio changing unit further By changing the gear ratio to the minimum RNGH _max value of the gear ratio that can be set, the torque shift can be reliably corrected, and the gear ratio control accuracy can be further improved.

[Brief description of drawings]

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

FIG. 2 is a schematic sectional view of a first control valve.

FIG. 3 is a flowchart showing an example of control, showing a measuring unit of an operating state of the engine.

FIG. 4 is a flowchart similarly showing an example of control, showing a shift control unit.

FIG. 5 is a flowchart similarly showing an example of control, showing a feedforward calculation unit.

FIG. 6 is a flowchart similarly showing an example of control, showing a control unit of the step motor.

FIG. 7 is a flowchart showing an example of control, showing an output unit to a step motor.

FIG. 8 is a graph showing how the step motor is controlled.

FIG. 9 is a graph showing a gear ratio characteristic under no load and showing a relationship between a displacement amount of a spool of a control valve and a gear ratio.

FIG. 10 is a graph showing a starting state when the vehicle is moving backward with the switching valve kept in a forward state, and is a graph showing a relationship between a control amount of a step motor, a vehicle speed, a throttle opening, a gear ratio, and time.

FIG. 11 is a schematic sectional view of a toroidal type continuously variable transmission.

FIG. 12 is a configuration diagram of a hydraulic control device.

FIG. 13 is a sectional view of the forward / backward movement detecting means.

FIG. 14 is a graph showing a gear ratio characteristic under no load in a conventional example, showing a relationship between a displacement amount of a spool of a control valve and a gear ratio.

FIG. 15 is a graph showing a starting state in the case of moving backward while keeping the switching valve in the forward state in the conventional example, and is a graph showing the relationship between the control amount of the step motor, the vehicle speed, the throttle opening, the gear ratio, and the time. .

FIG. 16 is a graph showing the state of torque shift and showing the relationship between the inclination angle of the power roller and the input torque.

FIG. 17 is a claim correspondence diagram corresponding to the first or second invention.

[Explanation of symbols]

2 Shift control controller 4 Hydraulic control device 5 shift lever 6 Input shaft rotation sensor 7 Output shaft rotation sensor 10 Toroidal type continuously variable transmission 12 Torque converter 16 input axes 18 1st toroidal transmission 20 2nd toroidal transmission 40 Forward / reverse switching device 60 First control valve 61 step motor 70 Second control valve 71 step motor 100 Lock-up prohibition valve 101 spool 102, 103 port 200 control means 201 First target gear ratio regulating means 202 Second target gear ratio regulating means 210 forward / reverse switching means 220 means for changing gear ratio

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-78366 (JP, A) JP-A-59-217051 (JP, A) JP-A-59-166672 (JP, A) JP-A-64- 49760 (JP, A) JP 3-103654 (JP, A) JP 8-303544 (JP, A) JP 3-181666 (JP, A) JP 2-292562 (JP, A) JP 62-191240 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 15/38 F16H 37/02 F16H 59/00-61/12 F16H 61/16-61 / 24 F16H 63/40-63/48

Claims (2)

(57) [Claims] 1. A gear ratio changing means for changing a gear ratio control direction according to forward and backward movement of a vehicle, a forward and backward switching means for switching the control direction of the gear ratio according to forward and backward movement of the vehicle, and an operating state of the vehicle. In a control device for a toroidal type continuously variable transmission including a control means for controlling a target gear ratio according to the above, and a control means for controlling the gear ratio changing means, a maximum value of the gear ratio settable by the gear ratio changing means is provided. than
A toroidal type continuously variable transmission including first target gear ratio regulating means for regulating the maximum value of the target gear ratio to a value that is reduced by an amount capable of correcting the gear ratio deviation according to the torque shift. Control device. 2. A gear ratio changing means for changing a gear ratio control direction according to forward and backward movement of the vehicle, a forward and backward switching means for switching the control direction of the gear ratio according to forward and backward movement of the vehicle, and an operating state of the vehicle. In a control device for a toroidal type continuously variable transmission including a control means for controlling a target gear ratio according to the above, and a control means for controlling the gear ratio changing means, a maximum value of the gear ratio settable by the gear ratio changing means is provided. than
A first target gear ratio regulating means for regulating the maximum value of the target gear ratio to a value that is reduced by an amount capable of correcting the gear ratio deviation according to the torque shift; and a gear ratio that can be set by the gear ratio changing means. Than the minimum
Toroidal type continuously variable transmission, comprising: a second target gear ratio regulating means for regulating the minimum value of the target gear ratio to a value large enough to correct the shift of the gear ratio according to the torque shift. Machine control device.