JP2000002326A - Lockup control for continuously variable transmission and shift control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely lock up a continuously variable transmission at the selected time of any gear ratio, by a transmission input side rotation frequency causing no problem about oil quantity increase/decrease at every oil temperature. SOLUTION: Lockup is made under the condition that when oil temperature TMP exceeds TMP2, a transmission input side rotation frequency is made a lockup rotation frequency NL2 or more at middle temperature time higher than a lockup rotation frequency NL1 at normal time, and that at the time of TMP>TMP4, an input side rotation frequency is made a lockup rotation frequency NL3 at high temperature time or more higher than the lockup rotation frequency NL2 at the middle temperature time. The increase of a lockup rotation frequency NL in accordance with the increase of oil temperature eliminates lockup in a low rotation region for worsening oil quantity increase/decrease due to the increase of oil temperature, thereby preventing the durability lowering of a lockup clutch. Also performing lockup control, by monitoring a transmission input side rotation frequency without using a vehicle speed, can eliminate a situation such as unperformed lockup even in a high rotation region incapable of causing a problem about the oil quantity increase/decrease because of a low speed side gear ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up control device for inserting a torque converter inserted into a transmission system of a continuously variable transmission into a lock-up state in which input and output elements are directly connected, and The present invention relates to a shift control device for a continuously variable transmission mechanism in a continuously variable transmission.

[0002]

2. Description of the Related Art Since a torque converter transmits power between input and output elements via a fluid, it performs a torque fluctuation absorbing function and a torque increasing function, but has poor transmission efficiency. For this reason, in a torque converter inserted into a transmission system of an automatic transmission for a vehicle, the torque converter is required under running conditions (in a lock-up region) where the torque fluctuation absorbing function and the torque increasing function are unnecessary. Into a lock-up state in which the input and output elements are mechanically directly connected by the engagement of the lock-up clutch. Under other driving conditions (in the converter area), the torque converter is directly connected by releasing the lock-up clutch. The so-called lock-up type torque converter, which is in a converter state in which is released, is widely used today.

[0003] Lock-up control of this type of torque converter will be described in the case of a stepped automatic transmission. For example, "NISSN RE4R01A type full-range electronic control" issued in March 1987 by Nissan Motor Co., Ltd. As described in "Automatic Transmission Maintenance Manual" (A261C07) and JP-A-9-242865, a lockup area is determined by the vehicle speed, and when the vehicle speed exceeds the lockup vehicle speed, the torque converter is locked. It was usual to do.

When the viscosity of the hydraulic oil of the transmission is reduced due to an increase in the oil temperature, the amount of hydraulic oil leaking from a control valve body that controls shift control increases, and the rotational speed of the engine that drives the oil pump decreases. When low (low vehicle speed)
In addition, the hydraulic oil amount of the automatic transmission tends to be insufficient, causing a problem that the lock-up clutch of the torque converter slips and durability is reduced.

In order to solve this problem, in a stepped automatic transmission, conventionally, the lock-up vehicle speed is increased when the operating oil temperature rises, and the torque converter is locked at a low vehicle speed where the amount of operating oil tends to be insufficient. It is proposed not to let it go up.

[0006]

In a stepped automatic transmission, the gear stage at which the torque converter is locked up is specified. By increasing the lockup vehicle speed when the temperature rises, it is possible to avoid a decrease in the durability of the lockup clutch due to the deterioration of the oil balance at the time of the high temperature. However, if the same countermeasure is applied to the continuously variable transmission, the continuously variable transmission can select the gear ratio in a stepless manner, and the engine speed increases due to the selected gear ratio even under the same lock-up vehicle speed. Due to the difference, the engine speed is high due to the low speed side gear ratio, the oil balance does not deteriorate even at high oil temperature, and the lockup is not performed even though the torque converter should be locked up. This may cause a problem such that the effect of improving the transmission efficiency by lock-up is impaired.

According to the first aspect of the present invention, in view of the above situation, in the case of a continuously variable transmission, it is preferable that the lock-up control factor be set to the transmission input side input speed instead of the vehicle speed. It is an object of the present invention to propose a lockup control device for a continuously variable transmission that realizes this idea based on fact recognition and does not cause the above-described problem.

The second invention according to claim 2 follows the lock-up control of the first invention. In this case, the narrowing of the lock-up region at a high oil temperature is caused by the reduction in the speed of the continuously variable transmission during acceleration. The objective is to impair the direct feeling, which is our mission, and to increase the frequency of lock-up, thereby deteriorating the operability of vehicles with continuously variable transmissions. I do.

According to a third aspect of the present invention, when the shift control according to the second aspect of the invention is followed, the engine brake becomes excessively large. Therefore, a lock-up release control for solving this problem is also proposed. Aim.

A fourth object of the present invention is to propose a suitable return condition for returning the lock-up region from the changed state to the original state when the oil temperature drops.

[0011]

For these purposes, the lock-up control device of the continuously variable transmission according to the first invention is brought into a lock-up state in which the input / output elements are directly connected in a predetermined operating state. In a continuously variable transmission provided with a torque converter in a transmission system, the torque converter is configured to be in a lockup state when the input side rotation speed of the continuously variable transmission is equal to or higher than a lockup rotation speed, and the lockup rotation speed Is increased as the transmission operating oil temperature increases.

According to a second aspect of the present invention, there is provided a continuously variable transmission lock-up control and transmission control device including a torque converter in a transmission system, which is in a lock-up state in which input / output elements are directly connected in a predetermined operation state, and has a vehicle speed and a transmission speed. In the continuously variable transmission that is shifted based on a predetermined shift pattern that defines a target input-side rotation speed of the continuously variable transmission according to an engine load,
The torque converter is configured to be in a lockup state when the input side rotation speed of the continuously variable transmission is equal to or higher than the lockup rotation speed, and the lockup rotation speed is configured to increase as the transmission operating oil temperature increases. When the lock-up rotation speed is increased, the lower limit target input-side rotation speed when the engine is not loaded on the shift pattern is increased to the same value as the lock-up rotation speed. .

According to a third aspect of the present invention, there is provided the lock-up control and the shift control device for the continuously variable transmission according to the second aspect of the invention, wherein the speed of the continuously variable transmission is shifted so that the input side speed of the continuously variable transmission becomes the lower limit target input side speed. When the engine is in a no-load state in a state in which the torque converter is in a locked state, lock-up of the torque converter is prohibited.

The lockup control and the shift control device for the continuously variable transmission according to the fourth invention are the same as those of the first to third inventions.
In any one of the inventions, the lock-up rotation speed and the lower limit target input-side rotation speed in response to a decrease in the transmission operating oil temperature are restored only when the engine is in a loaded state. It is assumed that.

[0015]

According to the lock-up control device of the first invention, when the input-side rotational speed of the continuously variable transmission becomes equal to or higher than the lock-up rotational speed, the torque converter is brought into a lock-up state in which the input and output elements are directly connected. . Further, the lockup control device for the continuously variable transmission according to the first invention further increases the lockup rotation speed as the transmission operating oil temperature increases.

Therefore, as described above, lockup is not performed in the low rotation speed range of the transmission input side rotation speed where the oil amount balance deteriorates as described above due to an increase in the transmission operating oil temperature.
For this reason, it is possible to prevent the lock-up from being performed under these oil temperature conditions and the rotation range, thereby deteriorating the durability of the lock-up clutch. In addition, since the lock-up control is performed by monitoring the speed of the transmission input side instead of the vehicle speed, the speed ratio can be selected in a stepless manner, and the engine speed deteriorates the oil balance due to the low speed side speed ratio. Thus, it is possible to eliminate a situation in which lockup is not performed even though there is no lockup, and it is possible to eliminate the problem that the transmission efficiency improvement effect due to lockup is impaired.

In the second invention, lock-up control similar to that in the first invention is performed. In this case, when the lock-up rotation speed is increased in response to a high oil temperature, the lock-up region becomes narrow. Lockup will not occur when the engine is not loaded, and the mission of the continuously variable transmission will be impaired during acceleration in the future, or the frequency of lockup will be increased, which will deteriorate the operability of vehicles equipped with a continuously variable transmission. . However, in the second invention, the lower limit target at the time of no engine load on a predetermined shift pattern that defines the target input-side rotation speed of the continuously variable transmission in accordance with the vehicle speed and the engine load used in the shift control of the continuously variable transmission. Since the input side rotation speed is increased to the same value as the lockup rotation speed when the lockup rotation speed is increased,
Lock-up is performed even when the transmission is controlled so that the transmission input-side rotation speed reaches the lower limit target input-side rotation speed when the engine is not loaded, and during acceleration from here on, the mission of the continuously variable transmission is It is possible to secure a certain direct feeling, prevent the lock-up frequency from increasing, and solve the above-described problem that the operability of the vehicle with the continuously variable transmission deteriorates.

When the lower-limit target input-side rotational speed at the time of no engine load is increased to the same value as the increased lock-up rotational speed as in the second invention, the engine brake becomes excessively large, causing a sense of incongruity. However, in the third aspect, lockup of the torque converter is prohibited when the engine is in a no-load state in a state where the input side rotation speed of the continuously variable transmission is shifted so as to be the lower limit target input side rotation speed. Therefore, it is possible to avoid occurrence of the problem related to the excessive engine brake.

In the fourth invention, the lock-up rotation speed and the lower-limit target input-side rotation speed increased at the time of high oil temperature in each of the above inventions are reduced and returned in accordance with a decrease in the transmission operating oil temperature. , Only when the engine is under load. For this reason, if the reduction return is performed when the engine is not loaded, it is easy to feel a shock due to the shift and a change in the state of the torque converter, and while feeling uncomfortable, the shock is no longer felt and the uncomfortable feeling is avoided. be able to.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a drive system of a vehicle with a continuously variable transmission equipped with a lock-up control and a shift control device according to an embodiment of the present invention, 1 is an engine, 2 is a torque converter, 3 is a V-belt type, A toroidal-type continuously variable transmission mechanism, 4 is a differential gear device, and 5 is wheels, which are sequentially drive-coupled as shown to form a drive system of the vehicle.

A torque converter 2 for drivingly coupling the engine 1 to a continuously variable transmission mechanism 3 includes a pump impeller 2 a as an input element driven by the engine 1 and an output element coupled to an input shaft of the continuously variable transmission mechanism 3. Turbine runner 2
b, and a lock-up clutch 2c that directly connects the pump impeller 2a and the turbine runner 2b.

[0022] entered into force of the lock-up clutch 2c is determined by the differential pressure of the apply pressure P _A and the release pressure P _R in the before and after (the lock-up clutch engagement differential pressure), apply pressure P _A is lower than the release pressure P _R For example, the lock-up clutch 2c is released and does not directly connect between the pump impeller 2a and the turbine runner 2b, so that the torque converter 2 functions in a converter state in which the slip is not limited.
When apply pressure P _A is larger than the differential pressure set value higher than the release pressure P _R, the lock-up clutch 2
c is fastened, the relative rotation between the pump impeller 2a and the turbine runner 2b stops, and the torque converter 2 functions in a lock-up state.

[0023] In this embodiment, the applied pressure in order to perform the predetermined lock-up control P _A and the release pressure P
_The lock-up control system that determines the differential pressure between _R (lock-up clutch engagement differential pressure) has the following configuration. The lock-up control valve 11 uses the line pressure P _L as the base pressure, and the differential pressure between the apply pressure P _A and the release pressure P _R according to the signal pressure P _S from the lock-up solenoid 13 that is ON / OFF controlled by the controller 12. (P _A -P _R ) are determined, and the lock-up control valve 11 and the lock-up solenoid 13 are known ones as shown in FIG.

[0024] That lockup solenoid 13 is supplied as a source pressure constant pilot pressure P _p, to generate a signal pressure P _S when subjected to lock-up command from the controller 12 (ON), the lock-up command If no signal pressure is applied, the signal pressure P _S is lost. The lock-up control valve 11, along with receiving the above signal pressure P _S and the fed-back release pressure P _R in one direction, receives a spring force and fed back apply pressure P _A of the spring 11a in the other direction, the following The differential pressure control is performed as described above.

[0025] That is, when supplied with the signal pressure P _S from the lock-up solenoid 13 in accordance with the output of the lock-up command from the controller 12 (ON), the lock-up control valve 11 apply pressure P _A and the release pressure P _R , that is, the lock-up clutch engagement differential pressure (P _A -P
_R ) is increased to a pressure difference equal to or higher than the set pressure, and the torque converter is brought into a lockup state by engaging the lockup clutch 2c. Lock-up control valve 11
Conversely, the lock-up command from the controller 12 is lost and the signal pressure P _S from the lock-up solenoid 13 is
Disappears, the lock-up clutch engagement differential pressure (P _A −
P _R ) is reduced to a negative value, and the torque converter 2 is brought into the converter state by releasing the lock-up clutch 2c.

The output or disappearance of the lock-up command to the lock-up solenoid 13 is determined by the controller 12, and the controller 12 indicates the load state of the engine 1 as shown in FIGS. Throttle opening sensor 21 for detecting throttle opening TVO
, A signal from an engine speed sensor 22 for detecting an engine speed N _e (or a transmission input speed) as a transmission input side speed, and a transmission output speed N _O.
, And a signal from an oil temperature sensor 25 for detecting the transmission operating oil temperature TMP.

Based on the input information, the controller 12 executes a control program shown in FIG. 3 to change the lock-up rotation speed used for the lock-up control of the torque converter 2 according to the hydraulic oil temperature TMP as follows. The shift pattern is corrected by the same control program as illustrated in FIG. 6, and based on the shift pattern,
As shown in FIG. 1, the target speed ratio i ^* is determined, and the speed of the continuously variable transmission mechanism 3 is controlled toward the target speed ratio.

First, at step 31, the hydraulic oil temperature TMP is equal to or higher than the oil temperature set value TMP ₂ (TMP ₄ ) at which the lock-up rotational speed should be increased from the viewpoint of the oil amount balance. It is determined whether or not. Here, the oil temperature set values TMP ₂ and TMP ₄ will be described.
The oil amount can lock up for each working oil temperature TMP from the viewpoint of balance transmission input rotational speed (engine speed) N _e
Is plotted and the input-side rotation speed region in which lockup is possible is expressed as a hatched region illustrated in FIG.

Based on this, in the present embodiment, the oil temperature
Set value TMP_Two, TMP_FourAre shown in FIG.
Determine the temperature. Then, the oil temperature set value TMP_TwoIn lock
Input speed (upper engine speed)
N_eLower limit N_L1And the oil temperature TMP is TMP_TwoIs less than
Set the normal lock-up rotation speed at normal temperature and set the oil temperature
Value TMP_FourInput rotation speed that can be locked up with
(Engine speed) N_eLower limit N_L2And the oil temperature TMP
TMP _Two~ TMP_FourLock-up rotation at medium temperature when
Number, and an appropriate rotation speed, for example, N_L1And N_L2Between
Transmission input side rotation speed (engine
Rotation speed) N_eThe value N_L3And the oil temperature TMP is TMP_Fourthat's all
Is the lockup rotation speed at high temperature.

However, the oil temperature set value TMP_Two, TMP_FourTo
In each case, the lock-up rotation speed N _L1To N_L2Rise to
Judgment and N_L2To N_L3Judgment and lock-up
If the same function is used to judge the rotation speed in the reverse direction,
Hunting, the oil temperature as shown in FIG.
Set value TMP_Two, TMP_FourAre each locked up
Number N_LHydraulic oil temperature TMP
Oil temperature set value TMP_Two, TMP_FourLock when it's over
Up rotation speed N_LThe corresponding N of_L1To N_L2Rise to
And N_L2To N_L3To rise to TMP
_Two, TMP_FourOil temperature set value TMP slightly lower than
₁And TMP _ThreeIs the lockup rotation speed N_LJudgment of decrease
The hydraulic oil temperature TMP is used for these oil temperature set values TMP
₁, TMP_ThreeLock-up rotation speed N when it falls below
_LThe corresponding N of_L2To N_L1And N_L3To N
_L2To be reduced.

However, in FIG. 3, for convenience of explanation, the lock-up rotation speed N is set based on the oil temperature set values TMP ₁ and TMP _2.
The _L and only representatively explained the case of switching between the N _L1 and N _L2, the oil temperature set value TMP _3, TMP ₄ lockup rotational speed relative to the N _L of between N _L2, N _L3 Regarding the switching, only the corresponding portions are indicated by reference numerals in parentheses. When it is determined in step 31 that the hydraulic oil temperature TMP is not higher than the oil temperature set value TMP ₂ (TMP ₄ ),
Since the lockup rotation speed _NL is not changed, the control is terminated.

If it is determined in step 31 that the hydraulic oil temperature TMP is equal to or higher than the oil temperature set value TMP ₂ (TMP ₄ ),
In step 32, the lock-up rotational speed N _L as shown in FIG. 5 from the N _L1 to N _L2 (from N _L2 to N _L3) with increasing, the purpose of the details will be described later, the throttle opening as shown in FIG. 6 Engine no load (throttle opening TVO / 0) on a shift pattern that defines a target input side rotation speed (engine rotation speed) _Ne ^* between TVO and vehicle speed VSP.
8) The lower limit target input side rotation speed N _eL ^* at the time is changed from N _e1 ^* at the normal time (same as the lock-up rotation speed at the normal time N _L1 ) to α
As shown by (β), the increased lock-up rotation speed N
_L2 (N _L3) equal to the N _e2 ^* (N _e3 ^*) to increase.

The lock-up rotation speed N thus increased
_LAnd lower limit target input side rotation speed N_eL ^*Lock based on
Up control and shift control are not shown in FIG.
Performed as usual by the program, with the following effects
Can be obtained. First, lock-up control
To clarify, the transmission input side rotation speed N_eIs locked up
Number N_LWhen this is the case, the lockup of FIGS. 1 and 2
A lock-up command is output to the solenoid 13 and torque
Converter 2 is locked by fastening lock-up clutch 2c.
Enter the lock-up state, and set the transmission input side_eIs locked
Rotation speed N_LLock-up
The lock-up command is lost to the
Release the lockup clutch 2c to convert the barter 2
Change to barter state.

By the way, according to the lock-up rotational speed N _L the increase in the oil temperature TMP from N _L1 to N _L2 from (N _L2 N
_Since the oil temperature TMP is increased, the lockup is not performed in a low rotational speed range of the transmission input side rotational speed where the oil amount balance deteriorates as described above due to the increase in the oil temperature TMP. For this reason, it is possible to prevent the lock-up from being performed under these oil temperature conditions and the rotation range, thereby deteriorating the durability of the lock-up clutch.

[0035] Moreover the lock-up control described above, since the performing by monitoring the transmission input speed N _e, rather than the vehicle speed, engine speed for low-speed side transmission ratio can select a gear ratio continuously is oil amount It is possible to eliminate such a situation that the lockup is not performed even though the balance does not deteriorate, and it is possible to eliminate the problem that the transmission efficiency improvement effect by the lockup is impaired.

Here, when the lock-up rotation speed _NL is increased in response to the high oil temperature, as shown by the solid line in FIG. 6, the lower limit target input side when the engine is not loaded (the throttle opening TVO = 0/8). If the rotation speed N _eL ^* is _maintained at N _e1 ^* at the normal time (same as the lock-up rotation speed at normal time N _L1 ), the input-side rotation speed _Ne becomes the lower limit target input-side rotation speed N _e1 when the engine is not loaded. ^{* This} means that lockup has not been performed in the state where the gearshift control is performed so that it becomes ^* , and the direct feeling that is the mission of the continuously variable transmission until the lockup is performed at the time of acceleration from now on In addition, the frequency of lock-up is increased, and the drivability of the vehicle with the continuously variable transmission is greatly deteriorated.

However, in the present embodiment,
Sometimes, at step 32 in FIG.
Lower limit target input side rotation when the throttle opening TVO = 0/8)
Number N _eL ^*To N at normal time as shown in FIG._e1 ^*(Normal lock
Up rotation speed N_L1Same as) to α (β),
Increased lock-up rotation speed N_L2(N_L3The same value N)
_e2 ^*(N_e3 ^*), And the shifting map of FIG.
Transmission speed N based on the_OSpeed V that can be calculated from
From SP and throttle opening TVO, target input side rotation speed
N_e ^*And this N_e ^*Is the transmission output speed N_ODivided by
Target gear ratio i calculated^*Is a continuously variable transmission mechanism as shown in FIG.
3 so that when the engine is not loaded,
Input side rotation speed N_eIs the lower limit target input side rotation speed N_eL ^*become
Lock-up is being performed during gear shifting control
This means that the continuously variable transmission
Being able to secure the direct feeling that is our mission
In addition, the lockup frequency can be prevented from increasing,
Solves the above-mentioned problem that the driveability of vehicles equipped with transmissions deteriorates.
Can be turned off.

As described above, at the same time as increasing the lockup rotation speed _NL , the lower limit target input side rotation speed _NeL ^* when the engine is not loaded (the throttle opening TVO = _0/8 ⁾ is represented by α in FIG. , Β, when the value is increased to the same value as the increased lock-up rotation speed, the engine brake becomes excessively large, which causes a sense of incongruity.

To solve this problem, in this embodiment,
In step 33 of FIG. 3, the transmission input side rotation speed N _e
Is less than or equal to the lower limit target input rotational speed _NeL ^* , and when it is determined in step 34 that the throttle opening TVO is in an idling state of 0/8, that is, the transmission input rotational speed _Ne is lower limit target. When the speed is controlled to be the input side rotational speed N _eL ^* and the engine is in a no-load state, the output of the lock-up command is prohibited in step 35 and the lock-up OFF command is issued in FIG. It is emitted to the lock-up solenoid 13 of FIG. Prohibition of lock-up of the torque converter can avoid occurrence of the problem related to excessive engine braking.

In step 34, the throttle opening TVO is set to 0.
If it is determined that the engine is not in the idling state of / 8, the problem relating to excessive engine braking does not occur. In step 37, it is determined whether or not the vehicle is already in the lockup state. Is returned to step 31, and if it is not in the lock-up state, in step 38, a lock-up ON command is issued to the lock-up solenoid 13 of FIGS. 1 and 2 to bring the torque converter into the lock-up state, and a direct feeling is secured. Avoid increasing lock-up frequency.

In step 32, the lock-up rotation speed N _L and the lower limit target input side rotation speed N _eL increased as described above.
^* , When it is determined that the throttle opening TVO is not in the idling state of 0/8 in step 39, and in step 40, the operating oil temperature TMP is set to the oil temperature set value TMP ₁ (TMP ₃ If it is determined that the rotation speed is less than or equal to the above, the rotation speed is reduced and returned in step 41. In other words the step 41, the conducive lockup rotational speed N _L from N _L2 to N _L1 (from N _L3 to N _L2) to said lock-up control lowers, the lower limit target input rotational speed N _eL ^* N _e2 ^* To N _e1 ^* (N _e3 ^* to N
_e2 ^* ) to reduce and contribute to the above-mentioned shift control.

In this embodiment, the oil temperature (TM)
P) According to the return of the lock-up rotation speed _NL and the lower limit target input side rotation speed _NeL ^{* at the time} of decrease, the return is performed when the engine is in the loaded state (the throttle opening T
VO is set to a value other than 0/8), the lock-up rotation speed N _L when the engine is not loaded (when the throttle opening TVO is 0/8) where a shock due to a shift or a change in the state of the torque converter is likely to be felt. When the lower target input side rotational speed N _eL ^* is returned to a lower level, the uncomfortable feeling can be avoided while giving a sense of incompatibility due to the shock caused by the speed change and the change in the state of the torque converter accompanying this.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing a drive system of a vehicle including a lock-up control and a shift control device according to an embodiment of the present invention and a control system thereof.

FIG. 2 is a system diagram showing a lock-up control system of the torque converter according to the embodiment.

FIG. 3 is a flowchart showing a change control of a lockup rotation speed and a change control of a lower limit target input side rotation speed executed by a controller in the embodiment.

FIG. 4 is a line exemplifying a lock-up rotation speed set in the present invention on a two-dimensional coordinate on which a lower limit value of a transmission input-side rotation speed which can be locked up on an oil amount balance for each transmission operating oil temperature is described. FIG.

FIG. 5 is an explanatory diagram showing a setting schedule of a lock-up rotation speed with respect to a transmission operating oil temperature.

FIG. 6 is a diagram showing an example of a change in the lower-limit target input-side rotation speed, which is changed in the present invention, on a shift diagram of a normal continuously variable transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 2a Pump impeller (input element) 2b Turbine runner (output element) 2c Lock-up clutch 3 Continuously variable transmission mechanism 4 Differential gear device 5 Wheel 11 Lock-up control valve 12 Controller 13 Lock-up solenoid 21 Throttle opening sensor 22 Engine rotation (transmission input side rotation) sensor 24 Transmission output rotation sensor 25 Oil temperature sensor

Claims (4)

[Claims] In a continuously variable transmission provided with a torque converter in a transmission system in a lockup state in which input and output elements are directly connected in a predetermined operation state, an input side rotation speed of the continuously variable transmission locks up. Lock-up of the continuously variable transmission, wherein the torque converter is configured to be in a lock-up state when the rotation speed becomes equal to or higher than the rotation speed, and the lock-up rotation speed is increased as the transmission operating oil temperature is higher. Control device. 2. A transmission system comprising a torque converter in a lock-up state in which input / output elements are directly connected in a predetermined operating state, and the target input-side rotational speed of the continuously variable transmission is determined according to a vehicle speed and an engine load. In a continuously variable transmission that is shifted based on a predetermined scheduled shift pattern, the torque converter is configured to be in a lock-up state when the input side rotation speed of the continuously variable transmission is equal to or more than a lock-up rotation speed. The lock-up rotation speed is increased as the transmission operating oil temperature is higher. When the lock-up rotation speed increases, the lower limit target input-side rotation speed when the engine is not loaded on the shift pattern is the lock-up rotation speed. A lock-up control and a shift control device for a continuously variable transmission, wherein the lock-up control and the shift control device are configured to be increased to the same value as the number. 3. The lockup of the torque converter according to claim 2, wherein the engine is in a no-load state in a state where the input side rotation speed of the continuously variable transmission is shifted to the lower limit target input side rotation speed. A lock-up control device for a continuously variable transmission, characterized in that the lock-up control device is configured to inhibit the transmission. 4. The method according to claim 1, wherein the lock-up rotation speed and the lower-limit target input-side rotation speed in response to a decrease in the transmission operating oil temperature are returned under a load state of the engine. A lock-up control and a shift control device for a continuously variable transmission, which are configured to be performed only at a certain time.