JP6763795B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a control device for a continuously variable transmission.

In recent years, as an automatic transmission for a vehicle, a continuously variable transmission (CVT (Continuously Variable Transmission)) that can change the gear ratio steplessly without a shift shock has been widely put into practical use. The continuously variable transmission includes, for example, a primary pulley, a secondary pulley, and a power transmission member such as a chain wound between these pulleys, and the groove width of each pulley is changed to wind the power transmission member. By changing the diameter, the gear ratio is changed steplessly. The control device of this continuously variable transmission controls the pressure of the oil (hydraulic oil) for the transmission to generate a shift pressure for changing the gear ratio and a clamp pressure for preventing the power transmission member from slipping. Let me.

By the way, at the time of cold start in an extremely cold region or the like, the temperature of the oil is low and the viscosity (kinematic viscosity) of the oil is high. When high-viscosity oil is used to lubricate continuously variable transmissions, friction loss increases and vehicle fuel consumption decreases. Further, in the case of a vehicle having a configuration in which the oil is warmed up by heat exchange between the transmission oil and the engine cooling water, if the oil temperature is low at the time of starting the engine, the temperature rise of the cooling water is hindered. As a result, the warm-up of the engine is hindered, so that the friction loss in the engine increases and the fuel consumption of the vehicle decreases.

Various technologies have been proposed to promote warming up of the oil for this transmission. For example, in Patent Document 1, in the case of a parking range, the turbine liner of the torque converter and the torque transmission shaft of the continuously variable transmission mechanism are directly connected by controlling the forward clutch and the reverse brake of the forward / backward switching device. Is disclosed. In the case of the parking range, the parking gear and the parking pole are engaged with each other to lock the tire side, and the torque transmission shaft cannot rotate. Therefore, by directly connecting the torque transmission shaft and the turbine liner, the slip between the pump impeller that rotates at the same speed as the engine and the turbine liner that has stopped rotating increases, and the temperature of the hydraulic oil in the torque converter rises. To rise.

Japanese Unexamined Patent Publication No. 10-159927

However, in the technique disclosed in Patent Document 1, in the case of a parking range, each part between the parking gear and the turbine liner of the torque converter is mechanically locked by making a direct connection state. Parts (forward clutch, reverse brake, continuously variable transmission mechanism, parking lock mechanism, etc.) may be worn or damaged, resulting in reduced reliability.

The present invention has been made to solve the above problems, and is a continuously variable transmission capable of promoting warming up of oil for a transmission without deteriorating reliability even in a parking range. It is an object of the present invention to provide a control device.

The control device for a continuously variable transmission according to the present invention is arranged between a torque converter, a transmission mechanism having a primary pulley and a secondary pulley around which a power transmission member is wound, and a secondary pulley and a parking gear of the transmission mechanism. It is a control device of a continuously variable transmission including a forward / backward switching mechanism having a forward clutch and a reverse clutch, and adjusts the pressure of oil supplied to the torque converter, the transmission mechanism, and the forward / backward switching mechanism, respectively. The hydraulic circuit, the oil temperature detecting means for detecting the temperature of the oil, and the hydraulic circuit are controlled so that the forward clutch is engaged or released according to the shift range, and the reverse clutch is engaged or released. The forward / backward clutch control means for controlling the circuit and the forward / backward clutch control means are controlled so as to release the forward clutch and the reverse clutch is controlled to be released, and the oil temperature is detected by the oil temperature detecting means. It is characterized by comprising a warm-up control means for controlling a hydraulic circuit so that a clutch pressure required for stopping the rotation of the transmission mechanism is generated when the temperature of the oil is equal to or lower than a predetermined temperature.

In the continuously variable transmission control device according to the present invention, when the forward clutch of the forward / backward switching mechanism is released and the reverse clutch is released, the clamp pressure of the transmission mechanism is increased when the oil temperature is equal to or lower than a predetermined temperature. Let me. As a result, the rotation of the transmission mechanism is stopped by increasing the clamping force with respect to the power transmission member. In response to this, the turbine liner of the torque converter is stopped. On the other hand, the pump impeller of the torque converter rotates according to the power input from the engine. As a result, the power (energy) input from the engine is lost due to shearing or collision of the oil in the torque converter, and the temperature of the oil can be raised by this heat. As described above, according to the control device for the continuously variable transmission according to the present invention, it is possible to promote the warming up of the oil.

As a result, the temperature of the oil increases, and the viscosity of the oil decreases. Friction loss is reduced by using this oil with a low viscosity for lubrication in a continuously variable transmission. Further, in the case of a vehicle having a configuration in which the oil is warmed up by heat exchange between the oil and the cooling water of the engine, the temperature rise of the cooling water is not hindered by promoting the warming up of the oil, and the friction in the engine. Loss is reduced. Thereby, the fuel efficiency of the vehicle can be improved.

Further, in the continuously variable transmission control device according to the present invention, for example, when the shift range is the parking range (for example, when the engine is started), the forward / backward advance is arranged between the transmission mechanism and the parking gear. Since each clutch of the switching mechanism is released, the transmission mechanism is not mechanically locked. In the case of the parking range, the parking gear is locked, but since the forward clutch and the reverse clutch of the forward / backward switching mechanism arranged between the transmission mechanism and the parking gear are released, the speed is changed from the drive wheel side. The mechanism is not mechanically locked. Therefore, for example, even when a large torque is input to the torque converter from the engine, the transmission mechanism can rotate. As a result, according to the continuously variable transmission control device according to the present invention, reliability does not decrease even in the case of a parking range.

In the continuously variable transmission control device according to the present invention, the forward / backward clutch control means controls the hydraulic circuit so that the forward clutch is released when the shift range is the parking range or the neutral range, and the reverse clutch is disengaged. It is preferable to control the hydraulic circuit so that it is released. With this configuration, when the shift range is the parking range or the neutral range, each clutch of the forward / backward switching mechanism is released, so that the transmission mechanism is not mechanically locked from the drive wheel side.

In the control device for the continuously variable transmission according to the present invention, the warm-up control means determines whether or not the rotation of the transmission mechanism has stopped, and increases the clamp pressure until it is determined that the rotation has stopped in the determination. It is preferable to control. With this configuration, the clamp pressure is increased while monitoring the actual rotation state of the transmission mechanism, so that the clamp pressure required to stop the rotation of the transmission mechanism can be generated with high accuracy.

In the continuously variable transmission control device according to the present invention, the warm-up control means sets a target clamp pressure required to stop the rotation of the transmission mechanism, and controls the clamp pressure so as to reach the target clamp pressure. It is preferable to do so. With this configuration, it is possible to generate the clamp pressure required to stop the rotation of the transmission mechanism without monitoring the rotation state of the transmission mechanism.

In the continuously variable transmission control device according to the present invention, it is preferable that the warm-up control means sets the target clamp pressure using the engine speed. With this configuration, the target clamp pressure for stopping the rotation of the transmission mechanism can be accurately set according to the input state to the torque converter at the time of warming up.

In the continuously variable transmission control device according to the present invention, it is preferable that the warm-up control means sets the target clamp pressure using the capacitance coefficient of the torque converter. With this configuration, the target clamp pressure for stopping the rotation of the transmission mechanism can be accurately set according to the capacitance coefficient of the torque converter.

In the continuously variable transmission control device according to the present invention, it is preferable that the warm-up control means sets the target clamp pressure using an index value indicating the viscosity of the oil. With this configuration, it is possible to accurately set the target clamp pressure for stopping the rotation of the transmission mechanism according to the viscosity of the oil during warm-up.

In the continuously variable transmission control device according to the present invention, the torque converter has a lockup clutch, and when the shift range is the parking range, the lockup clutch controls the hydraulic circuit so that the lockup clutch is released. It is preferable to provide a control means. With this configuration, the lockup clutch is released in the case of the parking range, so the above-mentioned is described by the turbine liner whose rotation is stopped and the pump impeller which rotates according to the power input from the engine. The temperature of the oil can be raised in the torque converter as described above.

According to the present invention, it is possible to promote warming up of oil for transmission without deteriorating reliability even in the case of a parking range.

It is a block diagram which shows the structure of the control device of the continuously variable transmission which concerns on embodiment. It is a flowchart which shows the flow of the warm-up control of the control device of the continuously variable transmission which concerns on embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts. Further, in each figure, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

The continuously variable transmission control device 1 (hereinafter referred to as “control device 1”) according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a control device 1 according to an embodiment.

Before explaining the control device 1, the engine 2 and the continuously variable transmission 3 will be described. First, the engine 2 will be described. The engine 2 may be of any type, and is, for example, a horizontally opposed 4-cylinder gasoline engine. A continuously variable transmission 3 is connected to the crankshaft (output shaft) 2a of the engine 2. The engine 2 is controlled by an engine control unit (hereinafter referred to as "ECU (Engine Control Unit)") 20.

The ECU 20 is a control device that comprehensively controls the engine 2. The ECU 20 includes a microprocessor that performs calculations, a ROM that stores a program for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, and a backup RAM whose stored contents are maintained by a 12V battery. It is configured to have an input / output I / F and the like.

Various sensors such as an intake air amount sensor 21 and a crank angle sensor 22 are connected to the ECU 20 in order to acquire information necessary for control. The intake air amount sensor 21 detects the amount of air sucked from the air cleaner (not shown). The crank angle sensor 22 detects the rotation angle of the crankshaft 2a. The ECU 20 calculates (estimates) the engine torque (torque input to the continuously variable transmission 3) generated in the engine 2 by using, for example, the intake air amount or the like by a well-known estimation method. Further, in the ECU 20, for example, the engine speed is calculated from the rotation angle of the crankshaft 2a. The ECU 20 controls the fuel injection amount, ignition timing, and the like based on the detected values acquired from these various sensors and the calculated various values. The detection values of various sensors acquired by the ECU 20, the engine torque calculated by the ECU 20, the engine speed, and the like are determined by the transmission control unit (hereinafter, "TCU (Transmission Control Unit)" via CAN (Control Area Network) 60. (Description) is transmitted to 10.

Next, the continuously variable transmission 3 will be described. The continuously variable transmission 3 converts the power from the engine 2 and outputs the power. The continuously variable transmission 3 includes a torque converter 30, a variator 31 (corresponding to the transmission mechanism described in the claims), and a forward / backward switching mechanism 32.

The torque converter 30 has a clutch function and a torque amplification function. The torque converter 30 mainly includes a pump impeller 30a, a turbine liner 30b, and a stator 30c. The pump impeller 30a is connected to the crankshaft 2a of the engine 2 and power (torque) from the engine 2 is input to the pump impeller 30a. The pump impeller 30a produces an oil flow according to the power from the engine 2. The turbine liner 30b is arranged so as to face the pump impeller 30a. The turbine liner 30b transmits the power of the engine 2 from the pump impeller 30a via oil, and receives the transmitted power to rotationally drive the output shaft (primary shaft 31a of the variator 31 described later). The stator 30c is arranged between the pump impeller 30a and the turbine liner 30b. The stator 30c rectifies the discharge flow (return) from the turbine liner 30b and reduces it to the pump impeller 30a to generate a torque amplification action.

Further, the torque converter 30 includes a lockup clutch 30d that directly connects the input side (crankshaft 2a) and the output side (primary shaft 31a of the variator 31). The torque converter 30 amplifies and transmits the power of the engine 2 when the lockup clutch 30d is released (when not locked up), and when the lockup clutch 30d is engaged (when locked up). The power of the engine 2 is directly transmitted.

The variator 31 has a function of steplessly changing the gear ratio. The variator 31 mainly includes a primary shaft 31a, a secondary shaft 31b, a primary pulley 31c, a secondary pulley 31d, and a chain 31e (corresponding to the power transmission member described in the claims). The primary shaft 31a is connected to the turbine liner 30b of the torque converter 30. The power output from the torque converter 30 is input to the variator 31. The secondary shaft 31b is connected to the forward / backward switching mechanism 32. The variator 31 outputs power to the forward / backward switching mechanism 32.

A primary pulley 31c is provided on the primary shaft 31a. The primary pulley 31c has a fixed pulley 31f and a movable pulley 31g. The fixed pulley 31f is joined to the primary shaft 31a. The movable pulley 31g faces the fixed pulley 31f and is mounted so as to be slidable and relatively non-rotatable in the axial direction of the primary shaft 31a. The primary pulley 31c is configured so that the cone surface spacing (that is, the pulley groove width) between the fixed pulley 31f and the movable pulley 31g can be changed.

The secondary shaft 31b is arranged in parallel with the primary shaft 31a. A secondary pulley 31d is provided on the secondary shaft 31b. The secondary pulley 31d has a fixed pulley 31h and a movable pulley 31i. The fixed pulley 31h is joined to the secondary shaft 31b. The movable pulley 31i faces the fixed pulley 31h and is mounted so as to be slidable in the axial direction of the secondary shaft 31b and not to rotate relative to each other. The secondary pulley 31d is configured so that the width of the pulley groove between the fixed pulley 31h and the movable pulley 31i can be changed.

The chain 31e is hung and wound between the primary pulley 31c and the secondary pulley 31d. The chain 31e transmits power (torque) between the primary pulley 31c and the secondary pulley 31d.

In the variator 31, the gear ratio is changed steplessly by changing the pulley groove widths of the primary pulley 31c and the secondary pulley 31d and changing the ratio of the winding diameter of the chain 31e to the pulleys 31c and 31d (pulley ratio). To do. Assuming that the winding diameter of the chain 31e with respect to the primary pulley 31c is Rp and the winding diameter of the chain 31e with respect to the secondary pulley 31d is Rs, the gear ratio i is represented by i = Rs / Rp.

A primary drive oil chamber (hydraulic cylinder chamber) 31j is formed in the movable pulley 31g of the primary pulley 31c. A secondary drive oil chamber (hydraulic cylinder chamber) 31k is formed in the movable pulley 31i of the secondary pulley 31d. A gear shifting pressure for changing the pulley ratio (gear ratio) is supplied to the primary drive oil chamber 31j. A clamp pressure for preventing the chain 31e from slipping is supplied to the secondary drive oil chamber 31k.

The forward / backward switching mechanism 32 has a function of switching between forward rotation and reverse rotation (forward and reverse of the vehicle) of the drive wheels. The forward / backward switching mechanism 32 is arranged between the secondary pulley 31d of the variator 31 and the parking gear 33. The forward / backward switching mechanism 32 mainly includes a double pinion type planetary gear train 32a, a forward clutch 32b, and a reverse clutch (reverse brake) 32c. The forward / backward switching mechanism 32 is configured to be able to switch the power transmission path by controlling each state (engagement / release) of the forward clutch 32b and the reverse clutch 32c. An oil chamber is formed in the forward clutch 32b, and a clutch pressure for engaging the clutch is supplied to this oil chamber. An oil chamber is formed in the reverse clutch 32c, and a clutch pressure for engaging the clutch is supplied to this oil chamber.

When the drive range is selected by the operation of the shift lever 50 by the driver, the forward / backward switching mechanism 32 transmits the rotation of the secondary shaft 31b as it is by releasing the reverse clutch 32c and then engaging the forward clutch 32b. .. In this case, the vehicle can be moved forward. On the other hand, when the reverse range is selected by the operation of the shift lever 50 by the driver, the forward / backward switching mechanism 32 operates the planetary gear train 32a by releasing the forward clutch 32b and then engaging the reverse clutch 32c. The rotation of the secondary shaft 31b is reversed and transmitted. In this case, the vehicle can be driven backward. When the neutral range or h parking range is selected by the operation of the shift lever 50 by the driver, the forward / backward switching mechanism 32 releases the forward clutch 32b and the reverse clutch 32c to release the secondary shaft 31b and the drive wheel side. Disconnect (power transmission is cut off) and do not transmit power to the drive wheel side.

The parking gear 33 is fitted to the power transmission shaft 33a on the output side of the forward / backward switching mechanism 32. A parking pole 34 is provided so as to be swingable so that it can mesh with the parking gear 33. When the parking range is selected by the operation of the shift lever 50 by the driver, the parking pole 34 is swung and meshes with the parking gear 33, the parking gear 33 is locked, and the power transmission shaft 33a is fixed.

The shift lever (select lever) 50 described above is provided on the floor (center console) of the vehicle or the like. With the shift lever 50, for example, a drive range (D range), a manual range (M range), a parking range (P range), a reverse range (R range), and a neutral range (N range) can be selectively switched.

Each hydraulic pressure regulated by the valve body 40 (corresponding to the hydraulic circuit described in the claims) is supplied to the torque converter 30, the variator 31, and the forward / backward switching mechanism 32 described above. A control valve mechanism is incorporated in the valve body 40. This control valve mechanism is, for example, hydraulic pressure discharged from an oil pump (not shown) by opening and closing an oil passage formed in a valve body 40 by using a plurality of spool valves and solenoid valves that move the spool valves. Each hydraulic pressure is generated by adjusting (line pressure). The valve body 40 regulates the hydraulic pressure supplied to the torque converter 30 under the control of the TCU 10. Further, the valve body 40 regulates the shift pressure supplied to the primary drive oil chamber 31j of the variator 31 and the clamp pressure supplied to the secondary drive oil chamber 31k under the control of the TCU 10. Further, the valve body 40 regulates the hydraulic pressure supplied to the oil chambers of the clutches 31b and 31c in order to engage / release the clutches 31b and 31c of the forward / backward switching mechanism 32 under the control of the TCU 10.

The transmission oil (ATF (Automatic Transmission Fluid)) is used as a hydraulic oil for hydraulic control such as a torque converter 30, a variator 31, and a forward / backward switching mechanism 32, and a lubricating oil for lubrication. The vehicle may be provided with a mechanism (not shown) for exchanging heat between the oil and the cooling water of the engine 2.

Now, the control device 1 will be described. The control device 1 is a control device that comprehensively controls the continuously variable transmission 3. In particular, the control device 1 has a function of warming the oil in the torque converter 30 when the temperature of the oil is low when the shift range is the parking range (for example, when the engine 2 is started).

Each control of the control device 1 is carried out by the TCU 10. Like the ECU 20, the TCU 10 includes a microprocessor, a ROM, a RAM, a backup RAM, an input / output I / F, and the like.

The TCU 10 includes a primary pulley rotation speed sensor 11, a secondary pulley rotation speed sensor 12, an oil temperature sensor 13 (corresponding to the oil temperature detecting means described in the claims), and a range in order to acquire information necessary for control. Various sensors such as a switch 14 are connected. Further, the TCU 10 receives various information such as the engine speed and the engine torque from the ECU 20 via the CAN 60.

The primary pulley rotation speed sensor 11 detects the rotation speed of the primary pulley 31c (primary shaft 31a). The secondary pulley rotation speed sensor 12 detects the rotation speed of the secondary pulley 31d (secondary shaft 31b). In the TCU 10, the vehicle speed is calculated from the rotation speed of the secondary shaft 31b. The oil temperature sensor 13 detects the temperature of the oil. The range switch 14 is connected so as to move in conjunction with the shift lever 50, and detects the selected position of the shift lever 50.

The TCU 10 includes a variator control unit 10a, a lockup clutch control unit 10b (corresponding to the lockup clutch control means described in the claims), and a forward / backward clutch control unit 10c (forward / backward clutch described in the claims). It has a warm-up control unit 10d (corresponding to the warm-up control means described in the claims) and a warm-up control unit 10d (corresponding to the warm-up control means described in the claims). In the TCU 10, the processing of each of these parts 10a to 10d is realized by executing the program stored in the ROM by the microprocessor.

The variator control unit 10a automatically controls to shift the gear ratio steplessly according to the driving state of the vehicle according to the shift map. In this control, for example, a target value of the primary rotation speed is set so as to have a predetermined gear ratio, and the actual primary rotation speed (rotation speed detected by the primary pulley rotation speed sensor 11) becomes the target value. By controlling the valve body 40, a shift pressure is generated and the shift ratio is changed. The shift map is stored in the ROM in the TCU 10. Further, the variator control unit 10a sets a target value of the clamp pressure based on the engine torque or the like, and controls the valve body 40 so as to reach this target value to generate the clamp pressure, and the clamp pressure (clamping force). Controls to clamp the chain 31e. A margin hydraulic pressure is added to the clamp pressure in order to prevent the chain 31e from slipping and to reliably transmit the input torque to the variator 31 from the primary pulley 31c to the secondary pulley 31d.

The lockup clutch control unit 10b controls the valve body 40 to engage / release the lockup clutch 30d of the torque converter 30. In particular, the lockup clutch control unit 10b controls the valve body 40 so that the lockup clutch 30d is released when the shift range selected by the shift lever 50 is the parking range.

The forward / backward clutch control unit 10c controls the valve body 40 in order to engage / release the clutches 32b and 32c of the forward / backward switching mechanism 32. In particular, the forward / backward clutch control unit 10c controls the valve body 40 so that the forward clutch 32b is released and the reverse clutch 32c is released when the shift range selected by the shift lever 50 is the parking range. ..

When the oil temperature is low in the parking range, the warm-up control unit 10d controls the valve body 40 in order to increase the clamp pressure until the rotation of the variator 31 is stopped. Specifically, the warm-up control unit 10d determines whether or not the shift range selected by the shift lever 50 is the parking range. In the case of the parking range, the warm-up control unit 10d determines whether or not the oil temperature is equal to or lower than the warm-up control start temperature. The warm-up control start temperature is a temperature at which the oil temperature is low and warm-up is required. The warm-up control start temperature is determined by conformity. When the shift range is other than the parking range or when the oil temperature is higher than the warm-up control start temperature, the TCU 10 performs normal control (control by the variator control unit 10a described above) with respect to the clamp pressure.

When the temperature of the oil is equal to or lower than the warm-up control start temperature, the warm-up control unit 10d controls the valve body 40 so that the clamp pressure is increased by a predetermined pressure at predetermined time intervals. The predetermined pressure is determined by conformity. During this pressure increase control, the warm-up control unit 10d monitors at least one of the rotation speed of the primary pulley 31c and the rotation speed of the secondary pulley 31d, and determines whether or not the rotation of the variator 31 has stopped. judge. The warm-up control unit 10d continues the clamp pressure increase control when it is determined that the variator 31 is rotating, and performs the clamp pressure increase control when it is determined that the rotation of the variator 31 has stopped. finish.

When the rotation of the variator 31 is stopped, the warm-up control unit 10d determines whether or not the oil temperature is equal to or higher than the warm-up control end temperature. The warm-up control end temperature is a temperature at which the oil temperature becomes high and warm-up is not required. The warm-up control end temperature is determined by conformity. When the temperature of the oil is lower than the warm-up control end temperature, the TCU 10 controls the valve body 40 so as to maintain the clamping pressure required to stop the rotation of the variator 31. When the temperature of the oil becomes equal to or higher than the warm-up control end temperature, the TCU 10 returns to the normal control for the clamp pressure.

The clamping pressure (clamping force) required to stop the rotation of the variator 31 by the pressure boost control described above is the engine speed, engine torque, performance of the torque converter 30 (for example, capacitance coefficient), and oil viscosity (oil). It changes according to the temperature of the engine). For example, as the engine speed increases, the clamping pressure required to stop the rotation increases. As the engine torque increases, the clamping pressure required to stop rotation increases. When the capacitance coefficient of the torque converter 30 is high, the clamping pressure required for stopping the rotation is high. The higher the viscosity of the oil (the lower the temperature of the oil), the higher the clamping pressure required to stop the rotation.

The flow of warm-up control in the control device 1 (particularly, TCU 10) will be described with reference to FIG. 1 with reference to the flowchart of FIG. FIG. 2 is a flowchart showing a flow of warm-up control of the control device 1 according to the embodiment.

The TCU 10 determines whether or not the shift range detected by the range switch 14 is the parking range (S10). When it is determined in the determination of S10 that the parking range is not set, the TCU 10 ends the warm-up control and performs normal control for the clamp pressure.

When the parking range is determined in the determination of S10 (for example, when the engine 2 is started), the TCU 10 determines whether or not the temperature of the oil detected by the oil temperature sensor 13 is equal to or lower than the warm-up start temperature (S12). ).

In the case of the parking range, the lockup clutch 30d is released in the torque converter 30. Therefore, in the torque converter 30, the pump impeller 30a rotates according to the power (torque) input from the engine 2, and the power is transmitted to the turbine liner 30b via oil to rotate the turbine liner 30b. .. In the variator 31, the primary pulley 31c rotates according to the power input from the torque converter 31, and the power is transmitted to the secondary pulley 31d via the chain 31e, so that the secondary pulley 31d rotates. In the forward / backward switching mechanism 32, the forward clutch 32a is released and the reverse clutch 32b is released. The parking gear 33 is locked by the parking pole 34.

When it is determined in the determination of S12 that the temperature of the oil is higher than the warm-up start temperature, the TCU 10 ends the warm-up control and performs normal control for the clamp pressure. On the other hand, when it is determined in S12 that the oil temperature is equal to or lower than the warm-up start temperature, the TCU 10 detects the rotation speed of the primary pulley 31c detected by the primary pulley rotation speed sensor 11 and the secondary pulley rotation speed sensor 12. It is determined whether or not the rotation of the variator 31 has stopped by using at least one of the rotation speeds of the secondary pulley 31d (S14). The determination of S14 is repeated at predetermined time intervals until it is determined that the rotation of the variator 31 has stopped.

Every time it is determined in S14 that the rotation of the variator 31 has not stopped (during the rotation of the variator 31), the TCU 10 controls the valve body 40 in order to increase the clamp pressure by a predetermined pressure (S16). .. By this control, the valve body 40 supplies the secondary drive oil chamber 31k with a clamp pressure that is a predetermined pressure higher than the previous clamp pressure. By this pressure increase control, the clamping pressure is gradually increased, the clamping force (pressing force) against the chain 31e by the secondary pulley 31c is gradually increased, and the frictional force against the chain 31e is gradually increased. As a result, the rotation speed of the variator 31 gradually decreases.

When it is determined in the determination of S14 that the rotation of the variator 31 has stopped, the TCU 10 determines whether or not the temperature of the oil detected by the oil temperature sensor 14 is equal to or higher than the warm-up end temperature (S18). When it is determined in the determination of S18 that the temperature of the oil is lower than the warm-up end temperature, the TCU 10 returns to the determination of S14.

By generating a clamp pressure (clamping force) larger than that during normal control in this way, the rotation of the variator 31 is stopped. As a result, the rotation of the primary shaft 31a is stopped, so that the rotation of the turbine liner 30b of the torque converter 30 is also stopped, resulting in a stall state. On the other hand, since the power (torque) of the engine 2 is input to the pump impeller 30a of the torque converter 30, the pump impeller 30a rotates according to this power.

As described above, in the torque converter 30, the pump impeller 30a is rotating, but the turbine liner 30b facing the pump impeller 30a is stopped, so that the difference in rotation speed between the pump impeller 30a and the turbine liner 30b becomes large. .. As a result, the power (energy) input from the engine 2 to the pump impeller 30a becomes heat loss due to shearing or collision of the oil in the torque converter 30, and is converted into heat energy. This heat energy is directly transmitted to the oil in the torque converter 30 and absorbed by the oil. As a result, the oil is rapidly heated. The heated oil is used for lubrication of each part (variator 31, forward / backward switching mechanism 32, etc.) of the continuously variable transmission 3. As the temperature of the oil increases, the viscosity of the oil decreases, so that the oil having the reduced viscosity is used for lubrication, and the friction loss is reduced. The thermal energy generated by the heat loss is related to the above-mentioned parameters such as the engine speed, the performance of the torque converter 30, and the viscosity of the oil (oil temperature), and increases or decreases according to each of these parameters.

When the temperature of the oil is raised in this way and the temperature of the oil is determined to be equal to or higher than the warm-up end temperature in the determination of S18, the TCU 10 ends the warm-up control and returns to the normal control for the clamp pressure. By this normal control, the clamp pressure is reduced, so that the variator 31 can rotate.

Although the parking gear 33 is locked by the parking pole 34 even while the variator 31 is stopped rotating due to the warm-up control, the forward / backward switching mechanism 32 arranged between the variator 31 and the parking gear 33 Since the forward clutch 32b and the reverse clutch 32c are in the released state (because the variator 31 is not directly connected to the parking gear 33), the variator 31 is not mechanically locked. Therefore, for example, when a large torque is input to the torque converter 30 from the engine 2 and the rotation of the variator 31 cannot be stopped even with the increased clamping pressure, the variator 31 is not mechanically locked. It is possible to rotate according to the large torque. As a result, a large torque is not applied to the parts such as the parking pole 34, and the parts are not worn.

According to the control device 1 according to the embodiment, when the shift range is the parking range and the temperature of the oil for the transmission is low, the clamp pressure is increased to stop the rotation of the variator 31 to warm up the oil. It can be promoted. In particular, even when the temperature of the oil is very low at the time of cold start in an extremely cold region, the temperature of the oil can be raised rapidly.

As a result, the temperature of the oil increases, and the viscosity of the oil decreases. Friction loss is reduced by using the oil having a low viscosity for lubricating each part of the continuously variable transmission 3. Further, even in the case of a vehicle having a configuration in which the oil is warmed up by heat exchange between the oil and the cooling water of the engine 2, the temperature of the oil is rapidly raised at the time of cold start in an extremely cold region. The temperature rise of the cooling water is not hindered, and the friction loss in the engine 2 is also reduced. Thereby, the fuel efficiency of the vehicle can be improved.

Further, in the case of a configuration in which lubrication is performed by scraping up the oil by the rotation of the variator 31, a part of the scraped up oil hits the inner wall of the transmission case and flows down. If the temperature of the inner wall of the transmission case is very low (for example, during cold start in extremely cold regions), when the oil hits the inner wall of the transmission case and flows down, heat is taken from the oil and the temperature of the oil drops. .. However, according to the control device 1 according to the embodiment, since the rotation of the variator 31 is stopped at the time of cold start or the like, the pumping of the oil by the rotation of the variator 31 is also stopped, and the temperature of the oil can be raised efficiently. it can.

Further, the variator 31 normally rotates according to the power input from the engine 2 even in the parking range. During rotation, the variator 31 generates a sound (abnormal noise) due to contact between the pulleys 31c and 31d and the chain 31e and vibration of the chain 31e. However, according to the control device 1 according to the embodiment, in the case of the parking range, no abnormal noise is generated in the variator 31 while the rotation of the variator 31 is stopped.

Further, according to the control device 1 according to the embodiment, since the clutches 32a and 32b of the forward / backward switching mechanism 32 arranged between the variator 31 and the parking gear 33 are released, the variator 31 is mechanical. Since it is not locked to, reliability does not decrease even if the shift range is the parking range.

Further, according to the control device 1 according to the embodiment, the clamp pressure is gradually increased while monitoring the actual rotation state of the variator 31, so that the clamp pressure required to stop the rotation of the variator 31 is accurate. It can be generated well.

Further, according to the control device 1 according to the embodiment, since the lockup clutch 30d is in the released state in the parking range, it is input from the turbine liner 30b and the engine 2 stopped by the rotation stop at the variator 31. The temperature of the oil can be raised in the torque converter 30 by the pump impeller 30a that rotates according to the power.

Further, according to the control device 1 according to the embodiment, when the oil temperature is low in the parking range, it can be implemented by changing the control method for performing the crank pressure increase control different from the normal control, so that the existing hardware can be used. There is no need to add additional hardware to the configuration, and the oil can be warmed up at no cost.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, it is applied to the continuously variable transmission 3 provided with a chain type variator 31, but it is applied to a continuously variable transmission provided with a variator for transmitting power between pulleys by another power transmission member such as a belt type. You can also do it.

In the above embodiment, the actual rotation state of the variator 31 is monitored, and the clamp pressure is increased and controlled by a predetermined pressure until the rotation of the variator 31 is stopped, so that the clamp pressure required to stop the rotation of the variator 31 can be obtained. Although it is configured to be generated, the target clamp pressure required to stop the rotation in the variator 31 is set, and the valve body 40 is controlled so as to reach this target clamp pressure to generate the clamp pressure required to stop the rotation. May be. With this configuration, it is possible to generate the clamp pressure required to stop the rotation of the variator 31 without monitoring the rotation state of the variator 31.

For example, in the TCU 10, a target clamp pressure is set based on parameters such as the engine speed, the capacitance coefficient of the torque converter 30, and an index value (for example, the temperature of the oil) indicating the viscosity of the oil, and the set target clamp pressure is set. The valve body 40 is controlled so as to be. It is preferable to prepare a map showing the relationship between each parameter and the target clamp pressure in advance, store this map in the ROM in the TCU 10, and set the target clamp pressure using the map. By using the engine speed as a parameter, the target clamp pressure can be set accurately according to the input state from the engine 2 to the torque converter 30 at the time of warming up. Further, by using the capacitance coefficient of the torque converter 30 as a parameter, the target clamp pressure can be set accurately according to the capacitance coefficient of the torque converter 30. Further, by using an index value indicating the viscosity of the oil as a parameter, the target clamp pressure can be set accurately according to the viscosity of the oil at the time of warming up.

As a specific method, for example, the engine speed is acquired from the ECU 20, and the engine speed (rotation speed on the input side of the torque converter 30) and the primary pulley speed (torque) detected by the primary pulley speed sensor 11 are obtained. The capacitance coefficient of the torque converter 30 is obtained from the speed ratio with the rotation speed on the output side of the converter 30). For example, the capacitance coefficient is obtained using a map showing the relationship between the speed ratio of the torque converter 30 and the capacitance coefficient. Then, the engine torque (= capacity coefficient x engine speed ² ) is calculated from this capacity coefficient and the engine speed, and the target clamping pressure is obtained based on this engine torque. Further, the target clamp pressure may be obtained by adding the temperature of the oil detected by the oil temperature sensor 13 to the engine torque.

In the above embodiment, when the shift range is the parking range, the clutches 32b and 32c of the forward / backward switching mechanism 32 are released and the rotation of the variator 31 is stopped. For example, the shift range is the neutral range. In this case, the clutches 32b and 32c of the forward / backward switching mechanism 32 may be released and the rotation of the variator 31 may be stopped.

1 Control device 2 Engine 3 Continuously variable transmission 10 TCU
10a Variator control unit 10b Lock-up clutch control unit 10c Forward / backward clutch control unit 10d Warm-up control unit 11 Primary pulley rotation speed sensor 12 Secondary pulley rotation speed sensor 13 Oil temperature sensor 14 Range switch 30 Torque converter 30a Pump impeller 30b Turbine liner 30c Stator 30d Lockup clutch 31 Variator 31a Primary shaft 31b Secondary shaft 31c Primary pulley 31d Secondary pulley 31e Chain 32 Forward / backward switching mechanism 32a Planetary gear train 32b Forward clutch 32c Reverse clutch 33 Parking gear 34 Parking pole 40 Valve body 50

Claims (8)

A torque converter, a transmission mechanism having a primary pulley and a secondary pulley around which a power transmission member is wound, and a forward / backward movement having a forward clutch and a reverse clutch arranged between the secondary pulley and the parking gear of the transmission mechanism. A control device for a continuously variable transmission equipped with a switching mechanism.
A hydraulic circuit that adjusts the pressure of oil supplied to the torque converter, the transmission mechanism, and the forward / backward switching mechanism, respectively.
Oil temperature detecting means for detecting the temperature of oil and
A forward / backward clutch control means that controls the hydraulic circuit so that the forward clutch is engaged or released according to the shift range, and controls the hydraulic circuit so that the reverse clutch is engaged or released.
The forward / backward clutch control means controls the forward clutch to be released and the reverse clutch is controlled to be released, and the temperature of the oil detected by the oil temperature detecting means is equal to or lower than a predetermined temperature. If, the warm-up control means for controlling the hydraulic circuit so as to generate the clamp pressure required to stop the rotation in the transmission mechanism, and
A control device for a continuously variable transmission, characterized in that When the shift range is the parking range or the neutral range, the forward / backward clutch control means controls the hydraulic circuit so that the forward clutch is released, and the hydraulic circuit controls the hydraulic circuit so that the reverse clutch is released. The control device for a continuously variable transmission according to claim 1, wherein the control device is characterized. The warm-up control means is characterized in that it determines whether or not the rotation of the speed change mechanism has stopped, and controls the clamp pressure to be increased until it is determined in the determination that the rotation has stopped. The control device for a continuously variable transmission according to claim 2. Claim 1 or claim, wherein the warm-up control means sets a target clamp pressure required to stop rotation in the transmission mechanism, and controls the clamp pressure so as to reach the target clamp pressure. Item 2. The control device for the continuously variable transmission according to item 2. The control device for a continuously variable transmission according to claim 4, wherein the warm-up control means sets the target clamp pressure using the rotation speed of the engine. The control device for a continuously variable transmission according to claim 4 or 5, wherein the warm-up control means sets the target clamp pressure using the capacitance coefficient of the torque converter. The control of the continuously variable transmission according to any one of claims 4 to 6, wherein the warm-up control means sets the target clamp pressure using an index value indicating the viscosity of oil. apparatus. The torque converter has a lockup clutch and
The invention according to any one of claims 1 to 7, wherein when the shift range is a parking range, the lockup clutch control means for controlling the hydraulic circuit is provided so that the lockup clutch is released. The control device for the continuously variable transmission described.

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