JP5948234B2 - Control device and control method for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission mounted on a vehicle that stops and restarts a driving force source.

  The belt type continuously variable transmission is supplied with hydraulic pressure generated by a mechanical oil pump driven by an engine. The primary pulley and the secondary pulley are supplied with pulley pressure (primary pulley pressure and secondary pulley pressure) that uses this oil pressure as the original pressure. The belt is clamped by these pulley pressures, and by controlling these pulley pressures, the groove width of each pulley is changed, and a shift is performed.

  When a clutch that transmits power is connected in series to this belt type continuously variable transmission, in order to prevent the belt from slipping due to torque input, the clutch engagement force is set to be higher than the belt engagement force. A so-called clutch fuse control is performed to reduce the temperature.

  As such clutch fuse control, when clutch slip is detected, clutch fastening force and belt pressing force are respectively controlled to increase, and when slip is not detected, clutch fastening force and belt pressing force are respectively controlled to decrease. (See Patent Document 1).

Japanese Patent Laid-Open No. 10-002390

In recent years, for the purpose of improving fuel performance, so-called coast stop control is performed in which the engine is stopped not only when the vehicle stops but also before the vehicle stops. Even during coast stop control, if torque is input from the drive wheels due to sudden braking, stepping up, etc., belt slip may occur, so it is desirable to perform clutch fuse control even during coast stop control .

  However, in coast stop control, the mechanical oil pump driven by the engine cannot generate hydraulic pressure when the engine is stopped. Therefore, it is conceivable to provide an electric oil pump that supplies hydraulic pressure instead of the mechanical oil pump, and to perform clutch fuse control based on the hydraulic pressure generated by the electric oil pump during coast stop control.

  However, the actual oil pressure obtained by the oil pressure control does not necessarily match the command oil pressure due to variations. In such a case, the fastening force of the clutch is greater than the fastening force of the belt, and the belt slips due to the torque input from the drive wheels. For example, when a low actual hydraulic pressure is obtained with respect to the command hydraulic pressure for controlling the fastening force of the belt, or when a high actual hydraulic pressure is obtained with respect to the command hydraulic pressure for controlling the clutch fastening force, However, there is a possibility that the clutch engagement force is increased.

  In order to prevent the clutch engaging force from becoming larger than the belt engaging force due to the above-described variation, it is conceivable that the indicated hydraulic pressure of the clutch is further reduced from the hydraulic pressure at which the clutch fuse function is achieved. However, during coast stop control, an electric oil pump whose discharge pressure is lower than that of a mechanical oil pump is used as a hydraulic pressure source, so that excessive torque is not input from the drive wheels if the indicated hydraulic pressure to the clutch is too low. Nevertheless, the clutch may slip. When the clutch slips, problems such as a decrease in durability due to heat generation of the clutch and a decrease in reacceleration property due to the clutch engagement lug when a reacceleration is requested occur.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a continuously variable transmission control device capable of preventing belt slippage even when the engine is stopped by coast stop control. To do.

  According to an embodiment of the present invention, a continuously variable transmission mechanism mounted on a vehicle and capable of changing a gear ratio by changing a winding diameter of a power transmission belt that is clamped by hydraulic pressure supplied to a pulley, and a continuously variable transmission A frictional engagement element that is connected to the mechanism and transmits the driving force of the driving force source to the driving wheels in an intermittent manner, a coast stop control unit that stops the driving force source in a running state of the vehicle, and a non-driven by the driving force source. A first hydraulic pressure source that supplies hydraulic pressure to the step transmission mechanism and the frictional engagement element; and a second hydraulic pressure source that is disposed in parallel with the first hydraulic pressure source and that can supply hydraulic pressure to the continuously variable transmission mechanism and the frictional engagement element. It is applied to a control device for a continuously variable transmission provided. In the continuously variable transmission control device, a first urging portion that is disposed on the friction engagement element and has a first urging force that reduces a first transmission capacity obtained by hydraulic pressure from the first or second hydraulic power source; The second urging unit that is arranged in the continuously variable transmission mechanism and has a second urging force that increases the second transmission capacity obtained by the hydraulic pressure from the first or second hydraulic power source, and the driving force of the driving force source stop. When the second hydraulic power source supplies the hydraulic pressure, at least one of the first urging force and the second urging force so that the second transmission capacity becomes equal to or greater than the first transmission capacity in the entire hydraulic pressure region supplied by the second hydraulic power source. Is set.

  According to the above aspect, when the driving force source is stopped by the coast stop and the transmission capacity of the continuously variable transmission mechanism and the auxiliary transmission mechanism is controlled by the hydraulic pressure supplied from the second hydraulic power source instead of the first hydraulic pressure source, In the entire hydraulic pressure region supplied by the hydraulic power source, the second transmission capacity of the continuously variable transmission mechanism is set to be equal to or greater than the first transmission capacity of the auxiliary transmission mechanism. With such a configuration, even when the driving force source is stopped due to the coast stop and the hydraulic pressure decreases, the second transmission capacity of the continuously variable transmission mechanism becomes equal to or greater than the first transmission capacity of the auxiliary transmission mechanism. The power transmission belt of the step transmission mechanism is prevented from slipping.

It is a schematic block diagram of the vehicle carrying the continuously variable transmission of 1st Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the transmission controller of 1st Embodiment of this invention. It is explanatory drawing of the hydraulic circuit centering on the hydraulic control circuit of embodiment of this invention. It is explanatory drawing at the time of the coast stop control of embodiment of this invention. It is explanatory drawing which shows the relationship between the hydraulic pressure of embodiment of this invention, and transmission torque capacity. It is explanatory drawing of the primary pulley of the variator of embodiment of this invention. It is explanatory drawing of the friction fastening element of the subtransmission mechanism of embodiment of this invention. It is explanatory drawing which shows the relationship between the hydraulic pressure of embodiment of this invention, and transmission torque capacity. It is explanatory drawing which shows the relationship between the hydraulic pressure of embodiment of this invention, and transmission torque capacity.

  FIG. 1 is a schematic configuration diagram of a vehicle equipped with a continuously variable transmission according to a first embodiment of the present invention. This vehicle includes an engine 1 as a power source. The output rotation of the engine 1 is via a torque converter 2 with a lock-up clutch, a first gear train 3, a continuously variable transmission (hereinafter simply referred to as "transmission 4"), a second gear train 5, and a final reduction gear 6. Is transmitted to the drive wheel 7. The second gear train 5 is provided with a parking mechanism 8 that mechanically locks the output shaft of the transmission 4 at the time of parking.

  Further, the vehicle is supplied with the rotation of the engine 1 and is driven by using a part of the power of the engine 1. The electric oil pump 10 e is driven by receiving power supply from the battery 13. Is provided. Further, the transmission 4 includes a hydraulic control circuit 11 that adjusts the hydraulic pressure supplied from at least one of the mechanical oil pump 10 m and the electric oil pump 10 e and supplies the hydraulic pressure to each part of the transmission 4, the hydraulic control circuit 11, and the engine 1. And a controller 12 for controlling the above.

  The transmission 4 includes a continuously variable transmission mechanism (hereinafter referred to as “variator 20”) and an auxiliary transmission mechanism 30 provided in series with the variator 20. “To be provided in series” means that the variator 20 and the auxiliary transmission mechanism 30 are provided in series in the same power transmission path. The auxiliary transmission mechanism 30 may be directly connected to the output shaft of the variator 20 as in this example, or may be connected via another transmission or power transmission mechanism (for example, a gear train).

  The variator 20 is a belt-type continuously variable transmission mechanism that includes a primary pulley 21, a secondary pulley 22, and a belt (V belt) 23 that is wound around the pulleys 21 and 22. Each of the pulleys 21 and 22 includes a fixed conical plate, a movable conical plate that is arranged with a sheave surface facing the fixed conical plate, and forms a V-groove between the fixed conical plate, and the movable conical plate. The hydraulic cylinders 23a and 23b are provided on the back surface of the movable cylinder to displace the movable conical plate in the axial direction. When the hydraulic pressure supplied to the hydraulic cylinders 23a and 23b is adjusted, the width of the V groove changes, the contact radius between the belt 23 and each pulley 21 and 22 changes, and the speed ratio vRatio of the variator 20 changes steplessly. .

  The subtransmission mechanism 30 is a transmission mechanism having two forward speeds and one reverse speed. The sub-transmission mechanism 30 is connected to a Ravigneaux type planetary gear mechanism 31 in which two planetary gear carriers are connected, and a plurality of friction elements connected to a plurality of rotating elements constituting the Ravigneaux type planetary gear mechanism 31 to change their linkage state. Fastening elements (Low brake 32, High clutch 33, Rev brake 34) are provided. When the hydraulic pressure supplied to each of the frictional engagement elements 32 to 34 is adjusted and the engagement / release state of each of the frictional engagement elements 32 to 34 is changed, the gear position of the auxiliary transmission mechanism 30 is changed.

  For example, if the Low brake 32 is engaged and the High clutch 33 and the Rev brake 34 are released, the gear position of the subtransmission mechanism 30 is the first speed. If the high clutch 33 is engaged and the low brake 32 and the rev brake 34 are released, the speed stage of the subtransmission mechanism 30 becomes the second speed having a smaller speed ratio than the first speed. Further, if the Rev brake 34 is engaged and the Low brake 32 and the High clutch 33 are released, the shift speed of the subtransmission mechanism 30 is reverse. In the following description, it is expressed that “the transmission 4 is in the low speed mode” when the shift speed of the auxiliary transmission mechanism 30 is the first speed, and “the transmission 4 is in the high speed mode” when the speed is the second speed. Express.

  The controller 12 is a control means for comprehensively controlling the engine 1 and the transmission 4, and as shown in FIG. 2, a CPU 121, a storage device 122 including a RAM / ROM, an input interface 123, an output interface 124, , And a bus 125 for interconnecting them.

  The input interface 123 includes an output signal of an accelerator opening sensor 41 for detecting an accelerator pedal opening (hereinafter referred to as “accelerator opening APO”), an input rotational speed of the transmission 4 (= the rotational speed of the primary pulley 21). , Hereinafter referred to as “primary rotational speed Npri”), an output signal from the rotational speed sensor 42, an output signal from the vehicle speed sensor 43 that detects the traveling speed of the vehicle (hereinafter referred to as “vehicle speed VSP”), and the transmission 4. The output signal of the oil temperature sensor 44 for detecting the oil temperature of the engine, the output signal of the inhibitor switch 46 for detecting the position of the select lever 45, the output signal of the brake sensor 47 for detecting the brake pedal depression amount and the brake hydraulic pressure, etc. Entered.

  The storage device 122 stores a control program for the engine 1, a shift control program for the transmission 4, and a shift map used in the shift control program. The CPU 121 reads and executes a shift control program stored in the storage device 122, performs various arithmetic processes on various signals input via the input interface 123, and outputs a fuel injection signal, an ignition timing signal, a throttle An opening signal and a shift control signal are generated, and the generated shift control signal is output to the hydraulic control circuit 11 via the output interface 124. Various values used in the arithmetic processing by the CPU 121 and the arithmetic results are appropriately stored in the storage device 122.

  The hydraulic control circuit 11 includes a plurality of flow paths and a plurality of hydraulic control valves. The hydraulic control circuit 11 controls a plurality of hydraulic control valves on the basis of the shift control signal from the controller 12 to switch the hydraulic pressure supply path, and obtains the necessary hydraulic pressure from the hydraulic pressure generated by the mechanical oil pump 10m or the electric oil pump 10e. It is prepared and supplied to each part of the transmission 4. As a result, the gear ratio vRatio of the variator 20 and the gear position of the auxiliary transmission mechanism 30 are changed, and the transmission 4 is changed.

  In order to suppress fuel consumption, the controller 12 according to the present embodiment stops the rotation of the engine 1 while the vehicle is running, in addition to the idle stop control that stops the rotation of the engine 1 while the vehicle is stopped. Perform coast stop control.

  In coast stop control, while the vehicle is traveling in a low vehicle speed range immediately before stopping, the engine 1 is automatically stopped to suppress fuel consumption. The coast stop control is common in that the fuel cut control executed when the accelerator is off and the fuel supply to the engine 1 is stopped. However, the normal fuel cut control is executed during a relatively high speed running and the engine is stopped. While the lock-up clutch of the torque converter 2 is engaged to secure the brake, the coast stop control is executed at a relatively low speed traveling just before the vehicle stops, and the lock-up clutch is released and the engine 1 is The difference is that the rotation is stopped.

In executing the coast stop control, the controller 12 first determines the following conditions (a) to (d), for example.
(A): The foot is released from the accelerator pedal (accelerator opening APO = 0)
(B): The brake pedal is depressed (the brake sensor 47 is ON)
(C): Vehicle speed is a predetermined low vehicle speed (for example, 15 km / h) or less (d): Lock-up clutch is released Note that these conditions determine that the driver intends to stop in other words. It is a condition.

  When the coast stop condition is satisfied, the controller 12 stops the supply of fuel to the engine 1 and stops the rotation of the engine 1.

  FIG. 3 is an explanatory diagram of a hydraulic circuit centered on the hydraulic control circuit 11 according to the embodiment of the present invention.

  The hydraulic control circuit 11 receives the hydraulic pressure supplied from the mechanical oil pump 10m or the electric oil pump 10e, adjusts the hydraulic pressure, and supplies the hydraulic pressure to the variator 20 and the subtransmission mechanism 30, respectively.

  The hydraulic control circuit 11 includes a regulator valve 230, a secondary hydraulic control valve 220, and a shift control valve 210.

  The regulator valve 230 is a control valve that regulates the hydraulic pressure of the mechanical oil pump 10 m to a predetermined line pressure and supplies it to the oil passage 200. The secondary hydraulic control valve 220 is a control valve that regulates the secondary hydraulic pressure supplied to the hydraulic cylinder 23 b of the secondary pulley 22 using the line pressure as the original pressure.

  The shift control valve 210 is a control valve that regulates the primary hydraulic pressure supplied to the hydraulic cylinder 23a of the primary pulley 21 using the line pressure as the original pressure.

  A mechanical oil pump 10m and an electric oil pump 10e are connected to the hydraulic control circuit 11, and hydraulic pressure is supplied by these. The mechanical oil pump 10m is driven by the engine 1 to supply hydraulic pressure. The electric oil pump 10e is driven under the control of the controller 12 to supply hydraulic pressure when the hydraulic pressure cannot be supplied by the mechanical oil pump 10m, such as when the engine 1 is stopped.

  The hydraulic pressure output from the electric oil pump 10 e is supplied to the oil passage 200 via the relief valve 211 and the check valve 212. The check valve 212 prevents reverse hydraulic pressure from being applied to the electric oil pump 10e when the mechanical oil pump 10m is driven.

  The relief valve 211 regulates the upper limit value of the hydraulic pressure supplied by the electric oil pump 10e as will be described later.

  The regulator valve 230 and the secondary hydraulic control valve 220 are provided with solenoids. By controlling the duty ratio of these solenoids according to a command from the controller 12, the hydraulic pressure by each valve is controlled.

  Next, coast stop control of the vehicle configured as described above will be described.

  FIG. 4 is an explanatory diagram for coast stop control according to the embodiment of the present invention.

  The upper part of FIG. 4 shows the engine rotational speed Ne, and the lower part shows the hydraulic pressure supplied by the mechanical oil pump 10m (shown by a dotted line) and the hydraulic pressure supplied by the electric oil pump 10e (shown by a solid line).

  As described above, when the coast stop condition is satisfied, the controller 12 stops the supply of fuel to the engine 1 and stops the rotation of the engine 1 (timing t01).

  By the coast stop control, the rotational speed of the engine 1 gradually decreases. Along with this, the mechanical oil pump 10m that generates hydraulic pressure by the driving force of the engine 1 also gradually stops, and the hydraulic pressure from the mechanical oil pump 10m is not supplied to the hydraulic pressure control circuit 11 (timing t02).

  Even when the engine 1 is stopped, hydraulic pressure is required for the belt clamping force of each pulley of the variator 20 and the engagement of the frictional engagement element of the auxiliary transmission mechanism 30. Therefore, the controller 12 starts driving the electric oil pump 10e when the engine 1 is in the coast stop state (timing t01). Thereby, even if the hydraulic pressure is not supplied from the mechanical oil pump 10m, the hydraulic pressure of the electric oil pump 10e can be supplied to the hydraulic control circuit 11.

  Note that the hydraulic pressure that can be discharged by the electric oil pump 10e is smaller than that of the mechanical oil pump 10m. This is because the transmission 4 does not need to transmit torque when the engine 1 is stopped. This is because it is only necessary to secure the minimum hydraulic pressure necessary for fastening the transmission mechanism 30. Further, by reducing the capacity of the electric oil pump 10e, the size and weight of the electric oil pump 10e can be reduced.

  Thus, since the hydraulic pressure supplied becomes small in a coast stop state, the clamping force of the V belt 23 in the variator 20 falls. In particular, for example, when torque is input from the drive wheels 7 due to sudden braking, stepping, or the like, and this torque exceeds a transmission torque capacity that is a capacity (power transmission capacity) capable of transmitting power (torque) in the variator 20. In such a case, the V belt 23 may slip.

  Specifically, when the engine 1 is stopped by coast stop control, the mechanical oil pump 10m cannot be driven, so the hydraulic pressure is supplied only from the electric oil pump 10e, and the transmission torque capacity in the variator 20 and the subtransmission mechanism 30 is reduced. It will decline. Therefore, the hydraulic pressure of the variator 20 cannot be increased in order to prevent the V belt 23 from slipping.

  In order to prevent the V belt 23 from slipping, the controller 12 normally controls the transmission torque capacity of the variator 20 to be larger than the transmission torque capacity of the auxiliary transmission mechanism 30. However, in this case, since the hydraulic pressure is low, the resolution of the control is lowered and accurate control cannot be performed.

  In particular, when torque is input and the frictional engagement element of the subtransmission mechanism 30 slips, re-engagement is performed. However, because the hydraulic pressure is low, re-engagement takes time or re-engagement may occur. At this time, if a re-acceleration request is made, the hydraulic pressure is supplied from the mechanical oil pump 10m as the engine 1 is restarted, and a shock is generated by re-engaging the friction engagement element in the slip state.

  Further, when the engine 1 is driven, a change in the output torque of the engine 1 can be detected by an accelerator pedal opening, a fuel injection amount calculated by the controller 12, or the like. Thus, it is possible to control the variator 20 and the auxiliary transmission mechanism 30 to prevent the V belt from slipping by controlling the hydraulic pressure. In particular, the re-engagement after the auxiliary transmission mechanism 30 slips can be performed based on the change in the torque of the engine 1.

  On the other hand, at the time of coast stop control, the engine 1 is stopped and torque is input from the drive wheel 7 side. However, the input of torque cannot be predicted and the input speed is small because the vehicle speed is low. It becomes difficult to perform control for detection and re-fastening. Therefore, when a re-acceleration request is made, there is a possibility that a shock due to re-engagement of the frictional engagement element may occur.

  Therefore, it has been difficult in the coast stop control to perform a so-called clutch fuse that slips the frictional engagement element of the auxiliary transmission mechanism 30 in order to prevent the V belt 23 from slipping.

  On the other hand, in the embodiment of the present invention, the slipping of the V belt 23 of the variator 20 during the coast stop control is prevented by configuring as follows.

  FIG. 5 is an explanatory diagram showing the relationship between the hydraulic pressure and the transmission torque capacity in the variator 20 and the auxiliary transmission mechanism 30 according to the embodiment of the present invention.

  In FIG. 5, a solid line indicates a capacity (power transmission) in which power is transmitted by the V-belt 23 sandwiched by the variator 20 supplying hydraulic pressure to the hydraulic cylinders 23a and 23b provided in the primary pulley 21 and the secondary pulley 22, respectively. The relationship between the transmission torque capacity (capacity) and the hydraulic pressure is shown.

  The dotted line indicates that the frictional engagement element is engaged by supplying hydraulic pressure to any of the frictional engagement elements (Low brake 32, High clutch 33, Rev brake 34) that transmits power in the auxiliary transmission mechanism 30. Shows the relationship between the torque capacity and hydraulic pressure transmitted by.

  The variator 20 includes a second urging portion such as a spring that urges the V belt 23 in the clamping direction in order to prevent the V belt 23 from slipping even when the hydraulic pressure is reduced. Since the spring force (second urging force) of the second urging portion increases the clamping force of the V-belt 23, the variator 20 can exhibit a certain amount of transmission torque capacity S even when no hydraulic pressure is supplied. .

  On the other hand, the frictional engagement element of the subtransmission mechanism 30 is provided with a first urging portion such as a return spring that urges the release side to prevent dragging at the time of release. The spring force (first urging force) by the first urging portion acts to reduce the fastening force for frictional fastening. Therefore, in order for the frictional engagement element to have a transmission torque capacity, it is necessary to supply a hydraulic pressure larger than the hydraulic pressure P0 equivalent to the first biasing force of the first biasing portion.

  Further, the fading (friction material) of the frictional engagement element, the pulleys 21 and 22, and the V-belt 23 have different characteristics of the transmission torque capacity with respect to the increase in hydraulic pressure. The frictional engagement element increases the frictional force due to the increase in hydraulic pressure and increases the transmission torque capacity. However, since the pulleys 21 and 22 and the V-belt 23 are in contact with each other and the frictional force is not large, the transmission torque against the increase in hydraulic pressure. The increase in capacity is moderate compared to the frictional engagement element.

  Thus, since the variator 20 and the auxiliary transmission mechanism 30 have the characteristics shown in FIG. 5 with respect to the hydraulic pressure, the hydraulic pressure supplied to the variator 20 and the auxiliary transmission mechanism 30 in order to prevent the V belt 23 from slipping. Is set to a value smaller than P2 shown in FIG. 5 so that the transmission torque capacity in the variator 20 is always larger than the transmission torque capacity in the frictional engagement element of the auxiliary transmission mechanism 30.

  Therefore, in the embodiment of the present invention, the relief valve 211 that controls the upper limit value of the hydraulic pressure supplied by the electric oil pump 10e to the hydraulic pressure P2 is provided. When the electric oil pump 10e is driven, the upper limit of the hydraulic pressure supplied to the oil passage by the relief valve 211 is limited to the hydraulic pressure P2. That is, even if the electric oil pump 10e can generate a hydraulic pressure larger than the hydraulic pressure P2, the portion exceeding the hydraulic pressure P2 is drained by the relief valve 211 and does not exceed the hydraulic pressure P2. In FIG. 5, P1 indicates the minimum hydraulic pressure that can be supplied by the electric oil pump 10e. The hydraulic pressure P1 is set to the lowest value at which the frictional engagement element of the auxiliary transmission mechanism 30 does not cause a slip.

  As described above, when the mechanical oil pump 10m is stopped during the coast stop control, the hydraulic pressure is supplied to the variator 20 and the auxiliary transmission mechanism 30 by the electric oil pump 10e. The upper limit value of the hydraulic pressure at this time is limited by the relief valve 211, and the transmission torque capacity of the variator 20 is set to exceed the transmission torque capacity of the auxiliary transmission mechanism 30 as shown in the characteristic shown in FIG.

  Thus, even when the mechanical oil pump 10m is stopped during the coast stop control, the transmission torque capacity of the variator 20 exceeds the transmission torque capacity of the auxiliary transmission mechanism 30 in the entire hydraulic pressure region supplied by the electric oil pump 10e. Even when torque is input, the clutch fuse due to slipping of the frictional engagement element of the auxiliary transmission mechanism 30 is exhibited. Therefore, slippage of the V belt 23 of the variator 20 can be prevented even in a state where hydraulic pressure is supplied by the electric oil pump 10e, such as during coast stop control. If the characteristic of the electric oil pump 10e is set so that the upper limit of the hydraulic pressure supplied by the electric oil pump 10e is equal to the hydraulic pressure P2, the relief valve 211 need not be provided.

  Next, configurations of the variator 20 and the auxiliary transmission mechanism 30 will be described.

  FIG. 6 is an explanatory diagram of the primary pulley 21 of the variator 20 according to the embodiment of this invention. Since the configuration of the secondary pulley 22 is the same, the description thereof is omitted.

  In FIG. 6, the upper stage shows the case where the movable pulley 120 retreats and the winding diameter of the V belt 23 is small, and the lower stage shows the case where the movable pulley 120 advances and the winding diameter of the V belt 23 is large. .

  The primary pulley 21 is formed with a fixed pulley 110 at the end of the rotating shaft 100. A movable pulley 120 is slidably fitted on the outer periphery of the rotating shaft 100. The V belt 23 is sandwiched between the sheave surface 110 a of the fixed pulley 110 and the sheave surface 120 a of the movable pulley 120.

  The movable pulley is provided with a hydraulic chamber 130. By controlling the hydraulic pressure of the hydraulic chamber 130, the movable pulley 120 moves forward and backward with respect to the fixed pulley 110, the interval between the sheave surface 110a and the sheave surface 120a is changed, and the winding diameter of the V belt is changed. . By changing the winding diameter of the V-belt 23 between the primary pulley 21 and the secondary pulley 22, shifting is performed.

  The hydraulic chamber 130 is provided with a return spring 140. The return spring 140 functions as a second urging unit that urges the movable pulley 120 in the traveling direction with respect to the fixed pulley 110 to increase the clamping force of the V belt 23 by the second urging force. Even when the hydraulic pressure in the hydraulic chamber 130 is lowered by the return spring 140, the movable pulley 120 is urged toward the fixed pulley 110, sandwiching the V belt 23, and torque is transmitted by the V belt 23.

  With such a configuration, as shown in FIG. 5, the variator 20 can exhibit the transmission torque capacity S by the return spring 140 even when hydraulic pressure is not supplied.

  FIG. 7 is an explanatory diagram of a frictional engagement element of the auxiliary transmission mechanism 30 according to the embodiment of this invention.

  FIG. 7 illustrates the configuration of the high clutch 33, but the configurations of the low brake 32 and the rev brake 34 are the same, and thus the description thereof is omitted.

  The frictional engagement element transmits a driving force from the driving side to the driven side by the piston 320 movable by the hydraulic pressure supplied to the hydraulic chamber 310 sandwiching the driving friction plate 321 and the driven friction plate 322. Is done.

  The hydraulic chamber 310 is frictionally engaged by energizing the release side in order to prevent dragging due to contact between the driving friction plate 321 and the driven friction plate 322 during release. A return spring 330 is provided as a first urging portion that reduces the torque transmission capacity of the element with a first urging force.

  With such a configuration, as shown in FIG. 5, when the hydraulic pressure is not fastened to the friction engagement element, the transmission torque capacity is not provided. It is necessary to supply the hydraulic pressure P0 against one urging force.

  As described above, in the variator 20 and the auxiliary transmission mechanism 30, the relationship between the transmission torque capacity and the supply hydraulic pressure is determined by the return springs 140 and 330.

  Therefore, the transmission torque capacity of the variator 20 can be set to exceed the transmission torque capacity of the auxiliary transmission mechanism 30 also by changing the characteristics of the return springs 140 and 330.

  FIG. 8 is an explanatory diagram showing the relationship between the hydraulic pressure and the transmission torque capacity in the variator 20 and the auxiliary transmission mechanism 30 according to the embodiment of the present invention.

  In FIG. 8, the thick solid line and the thin solid line indicate the relationship between the transmission torque capacity and the hydraulic pressure in the variator 20, and the dotted line indicates the relationship between the transmission torque capacity of the frictional engagement element of the auxiliary transmission mechanism 30 and the hydraulic pressure.

  In FIG. 8, it is assumed that the maximum value and the minimum value of the hydraulic pressure that can be supplied by the electric oil pump 10e are P2 and P1. Here, it is assumed that the transmission torque capacity of the variator 20 has a characteristic indicated by a thin solid line. In this case, the region where the transmission torque capacity of the variator 20 exceeds the transmission torque capacity of the auxiliary transmission mechanism 30 is small depending on the hydraulic pressure generated by the electric oil pump 10e.

  Therefore, the spring characteristic of the return spring 140 of the variator 20 is changed so that the spring force is increased. By changing the spring characteristic of the return spring 140, the characteristic of the variator 20 is changed as shown by a thick solid line in FIG. Thus, the transmission torque capacity of the variator 20 can exceed the transmission torque capacity of the auxiliary transmission mechanism 30 in the range of the maximum value P2 and the minimum value P1 of the hydraulic pressure that can be supplied by the electric oil pump 10e. Specifically, the spring characteristic of the return spring 140 is changed so that the transmission torque capacity of the variator 20 is equal to or greater than the transmission torque capacity of the frictional engagement element at the hydraulic pressure P2. If the spring characteristics of the return spring 140 are excessively increased, the frictional force between the parts becomes excessive, and the fuel consumption deteriorates due to the increase in resistance and wear between the parts occurs. Therefore, in the hydraulic pressure P2, the transmission torque capacity of the variator 20 and the frictional engagement element It is desirable that the transmission torque capacity be set so as to match.

  FIG. 9 is an explanatory diagram showing a relationship between the hydraulic pressure and the transmission torque capacity in the variator 20 and the auxiliary transmission mechanism 30 according to the embodiment of the present invention.

  In FIG. 9, the thick solid line indicates the relationship between the transmission torque capacity and the hydraulic pressure in the variator 20, and the thick dotted line and the thin dotted line indicate the relationship between the transmission torque capacity of the frictional engagement element of the auxiliary transmission mechanism 30 and the hydraulic pressure.

  Similarly to FIG. 8, in FIG. 9, it is assumed that the maximum value and the minimum value of the hydraulic pressure that can be supplied by the electric oil pump 10e are P2 and P1. Here, it is assumed that the transmission torque capacity of the frictional engagement element of the auxiliary transmission mechanism 30 has a characteristic indicated by a thin dotted line. In this case, the region where the transmission torque capacity of the variator 20 exceeds the transmission torque capacity of the auxiliary transmission mechanism 30 is small depending on the hydraulic pressure generated by the electric oil pump 10e.

  Therefore, the spring characteristic of the return spring 330 of the subtransmission mechanism 30 is changed so that the spring force is increased. By changing the spring characteristics of the return spring 330, the characteristics of the auxiliary transmission mechanism 30 are changed as shown by the thick dotted lines in FIG. Thus, the transmission torque capacity of the variator 20 can exceed the transmission torque capacity of the auxiliary transmission mechanism 30 in the range of the maximum value P2 and the minimum value P1 of the hydraulic pressure that can be supplied by the electric oil pump 10e. Specifically, the spring characteristic of the return spring 330 is changed so that the transmission torque capacity of the variator 20 is equal to or greater than the transmission torque capacity of the frictional engagement element at the hydraulic pressure P2. If the spring characteristics of the return spring 330 are excessively increased, the hydraulic pressure required to start fastening increases when fastening the friction fastening elements in the released state, and it takes time to start fastening, and the fastening state of the friction fastening elements From the point that the hydraulic pressure required to maintain the fuel consumption increases, the responsiveness decreases and the fuel consumption deteriorates. Therefore, it is desirable to set the transmission torque capacity of the variator 20 and the transmission torque capacity of the frictional engagement element to coincide with each other at the hydraulic pressure P2.

  As described above, the transmission torque capacity of the variator 20 can also be changed by changing at least one of the spring force of the return spring 140 of the variator 20 and the spring force of the return spring 330 of the friction engagement element of the auxiliary transmission mechanism 30. It can be set to exceed the transmission torque capacity of the mechanism 30.

  Note that the spring force of the return spring 140 of the variator 20 is changed, the spring force of the return spring 330 of the friction engagement element of the auxiliary transmission mechanism 30 is changed, and the upper limit pressure of the relief valve 211 that regulates the output of the electric oil pump 10e. By changing at least one of them, the transmission torque capacity of the variator 20 can be set to exceed the transmission torque capacity of the auxiliary transmission mechanism 30.

  As described above, according to the embodiment of the present invention, the gear ratio can be changed by changing the winding diameter of the belt 23 mounted on the vehicle and clamped by the hydraulic pressure supplied to the pulleys (the primary pulley 21 and the secondary pulley). A continuously variable transmission mechanism (variator) 20, and a frictional engagement element (Low brake 32, High clutch 33, which is connected to the variator 20 and transmits the driving force of the engine 1 as a driving force source to the driving wheels 7 in an intermittent manner. Rev brake 34).

  A controller 12 configured as a coast stop control unit that performs a coast stop that stops the driving force source in a running state of the vehicle, and a first that is driven by the driving force of the engine 1 and supplies hydraulic pressure to the variator 20 and the frictional engagement element. A mechanical oil pump 10m as a hydraulic pressure source and a second hydraulic pressure that is arranged in parallel with the mechanical oil pump 10m and can supply hydraulic pressure to the variator 20 and the frictional engagement element even when the driving force of the engine 1 is stopped. And an electric oil pump 10e as a source.

  The sub-transmission mechanism 30 is obtained by hydraulic pressure from the first or second hydraulic power source, and controls a first transmission capacity that transmits and outputs the power of the engine 1 and controls the first transmission capacity to reduce the first transmission capacity. A return spring 330 is provided as a first urging portion having power, and the variator 20 is obtained by hydraulic pressure from the first or second hydraulic power source, and a second transmission capacity for transmitting and outputting the power of the engine 1 is controlled. And a return spring 140 as a second urging portion having a second urging force for increasing the second transmission capacity. When the driving force of the engine 1 is stopped and the electric oil pump 10e supplies hydraulic pressure, the second transmission capacity of the variator 20 is greater than or equal to the first transmission capacity of the auxiliary transmission mechanism 30 in the entire hydraulic pressure region supplied by the electric oil pump 10e. At least one of the first urging force and the second urging force is set so that

  With this configuration, when the driving force source is stopped by the coast stop and the transmission capacity of the variator 20 and the auxiliary transmission mechanism 30 is controlled by the hydraulic pressure supplied from the electric oil pump 10e instead of the mechanical oil pump 10m, In the entire hydraulic pressure region (minimum value P1 to maximum value P2) supplied by the electric oil pump 10e, the second transmission capacity of the variator 20 biased to the fastening side by the return spring 140 is biased to the release side by the return spring 330. Therefore, when the torque is input, the clutch fuse is exhibited by slipping of the frictional engagement element of the auxiliary transmission mechanism 30, and the variator The slip of 20 V belts 23 can be prevented. This effect corresponds to claim 1.

  Note that the maximum value of the hydraulic pressure that can be supplied by the electric oil pump 10e is P2, and the entire hydraulic pressure area in which the electric oil pump 10e is used is configured from the minimum value P1 to the maximum value P2. Thereby, when the supply hydraulic pressure of the electric oil pump 10e is used in the region from the minimum value P1 to the maximum value P2, the transfer torque capacity of the variator 20 in the entire hydraulic pressure region of the electric oil pump 10e is the transfer torque capacity of the friction engagement element. Since it can be controlled to exceed, no matter what hydraulic pressure is supplied from the electric oil pump 10e, the V belt 23 does not slip.

  Alternatively, although the maximum value of the hydraulic pressure that can be supplied by the electric oil pump 10e is P2, the present invention is not limited to this, and the entire hydraulic pressure range that uses the electric oil pump 10e is greater than the maximum value that can be supplied by the electric oil pump 10e. P2 may be set as a low oil pressure. That is, you may set so that it may become "P1 <P2 <maximum value which electric oil pump 10e can supply". In this case as well, the transmission torque capacity of the variator 20 can be controlled so as to exceed the transmission torque capacity of the frictional engagement element in the entire hydraulic pressure region of the electric oil pump 10e, and the V belt 23 is used in the usage region of the electric oil pump 10e. Never slip.

  In addition, since at least one of the urging force of the return spring 330 and the urging force of the return spring 140 can be changed, the upper and lower limit values of the hydraulic pressure output from the electric oil pump 10e and the characteristics of the frictional engagement element and the transmission torque capacity of the variator 20 can be changed. On the other hand, the second transmission capacity of the variator 20 can be set to be greater than or equal to the first transmission capacity of the auxiliary transmission mechanism 30.

  In addition, since the lower limit value of the hydraulic pressure generated by the electric oil pump 10e, which is the second hydraulic pressure source, is set to a hydraulic pressure at which the frictional engagement element of the auxiliary transmission mechanism 30 can be engaged, it is possible to prevent the frictional engagement element from being released. Thus, it is possible to improve the responsiveness and suppress the shock when the re-acceleration is requested after the coast stop control. This effect corresponds to claim 2.

  In addition, a relief valve that regulates the upper limit value of the hydraulic pressure supplied by the electric oil pump 10e so that the second transmission capacity of the variator 20 and the first transmission capacity of the subtransmission mechanism 30 are equal to or less than the hydraulic pressure P2 that corresponds to the hydraulic pressure. 211. By this relief valve 211, when the electric oil pump 10e is driven, the upper limit of the hydraulic pressure supplied to the oil passage is limited to the hydraulic pressure P2. That is, even if the electric oil pump 10e can generate a hydraulic pressure larger than the hydraulic pressure P2, the portion exceeding the hydraulic pressure P2 is drained by the relief valve 211 and can be controlled so as not to exceed the hydraulic pressure P2. The slip of the V belt 23 can be prevented. This effect corresponds to the third aspect.

  In addition, the relief valve 211 drains the hydraulic pressure when the hydraulic pressure supplied to the electric oil pump 10e becomes larger than the second transmission capacity of the variator 20, so that the first transmission capacity of the auxiliary transmission mechanism 30 becomes larger. The hydraulic pressure can be supplied so that the first transmission capacity of the subtransmission mechanism 30 is larger than the second transmission capacity of 20. This effect corresponds to claim 4.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  For example, in the above embodiment, a belt type continuously variable transmission mechanism is provided as the variator 20, but the variator 20 is a continuously variable transmission mechanism in which a chain is wound around pulleys 21 and 22 instead of the belt 23. May be. Alternatively, the variator 20 may be a toroidal continuously variable transmission mechanism in which a tiltable power roller is disposed between the input disk and the output disk.

  In the above-described embodiment, the sub-transmission mechanism 30 is a transmission mechanism having two stages of first speed and second speed as the forward shift stage. A transmission mechanism having stages may be used.

  Further, although the auxiliary transmission mechanism 30 is configured using a Ravigneaux type planetary gear mechanism, the configuration is not limited to such a configuration. For example, the subtransmission mechanism 30 may be configured by combining a normal planetary gear mechanism and a frictional engagement element, or a plurality of power transmission paths configured by a plurality of gear trains having different gear ratios, and these powers You may comprise by the frictional engagement element which switches a transmission path.

  Further, the auxiliary transmission mechanism 30 may be in the front stage or the rear stage with respect to the variator 20. For example, when the auxiliary transmission mechanism 30 is provided in the rear stage of the engine 1 and in the front stage of the variator 20, it is particularly effective for impact torque from the engine 1. On the other hand, when the auxiliary transmission mechanism 30 is provided in the subsequent stage of the variator 20, it is particularly effective for the impact torque from the drive wheels 7. Furthermore, instead of the sub-transmission mechanism 30 having a gear position, only a forward / reverse switching mechanism or a clutch mechanism that performs only power interruption may be used.

DESCRIPTION OF SYMBOLS 1 Engine 4 Transmission 10m Mechanical oil pump 10e Electric oil pump 11 Hydraulic control circuit 12 Controller 20 Variator (continuously variable transmission)
21 Primary pulley 22 Secondary pulley 23 Belt 30 Sub-transmission mechanism 33 High clutch 41 Accelerator opening sensor 42 Rotational speed sensor 43 Vehicle speed sensor 47 Brake sensor 110 Fixed pulley 120 Movable pulley 130 Hydraulic chamber 140 Return spring 211 Relief valve 212 Check valve 330 Return spring

Claims (4)

A continuously variable transmission mechanism mounted on a vehicle and capable of changing a gear ratio by changing a winding diameter of a power transmission belt sandwiched by hydraulic pressure supplied to a pulley, and connected to the continuously variable transmission mechanism, A frictional engagement element for intermittently transmitting the driving force to the driving wheel;
A coast stop control unit for stopping the driving force source in a running state of the vehicle;
A first hydraulic pressure source that is driven by the driving force source and supplies hydraulic pressure to the continuously variable transmission mechanism and the frictional engagement element;
A second hydraulic power source disposed in parallel with the first hydraulic pressure source and capable of supplying hydraulic pressure to the continuously variable transmission mechanism and the frictional engagement element;
With
A first urging portion disposed on the friction engagement element and having a first urging force for reducing a first transmission capacity obtained by hydraulic pressure from the first or second hydraulic pressure source;
A second urging portion disposed in the continuously variable transmission mechanism and having a second urging force for increasing a second transmission capacity obtained by hydraulic pressure from the first or second hydraulic pressure source;
When the driving force of the driving force source is stopped and the second hydraulic pressure source supplies hydraulic pressure, the second transmission capacity is equal to or greater than the first transmission capacity in the entire hydraulic pressure region supplied by the second hydraulic pressure source. A control device for a continuously variable transmission, wherein at least one of the first urging force and the second urging force is set.   2. The continuously variable transmission control device according to claim 1, wherein the lower limit value of the hydraulic pressure generated by the second hydraulic power source is set to a hydraulic pressure at which a frictional engagement element of the auxiliary transmission mechanism can be engaged. A continuously variable transmission mechanism mounted on a vehicle and capable of changing a gear ratio by changing a winding diameter of a power transmission belt sandwiched by hydraulic pressure supplied to a pulley, and connected to the continuously variable transmission mechanism, A frictional engagement element for intermittently transmitting the driving force to the driving wheel;
A first hydraulic pressure source that is driven by the driving force source and supplies hydraulic pressure to the continuously variable transmission mechanism and the frictional engagement element;
A second hydraulic power source disposed in parallel with the first hydraulic pressure source and capable of supplying hydraulic pressure to the continuously variable transmission mechanism and the frictional engagement element;
With
In a control device for a continuously variable transmission that performs coast stop control for stopping the driving force source in a running state of the vehicle and control for driving the second hydraulic power source during execution of the coast stop control.
A regulating portion that regulates the hydraulic pressure supplied from the second hydraulic power source to a hydraulic pressure equal to or lower than a hydraulic pressure at which the power transmission capacity of the continuously variable transmission mechanism and the power transmission capacity of the frictional engagement element coincide with each other A continuously variable transmission control device comprising an oil passage.   The restriction portion is a relief valve, and when the hydraulic pressure supplied from the second hydraulic pressure source has a power transmission capacity of the friction engagement element larger than a power transmission capacity of the continuously variable transmission mechanism, the relief valve is hydraulically 4. The continuously variable transmission control device according to claim 3, wherein

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