JP2019095034A - Control method and control device of automatic transmission - Google Patents

Abstract

To prevent a mechanical oil pump from being driven by power from a drive wheel upon towing a vehicle.SOLUTION: An automatic transmission TM1 comprises: a mechanical oil pump 8 for receiving supply of power from a power transmission path, where the power transmission path connects a drive source 1 and a drive wheel 7 in a vehicle; an intermittent mechanism 15 disposed so as to be able to shut off transmission of power from the power transmission path to the mechanical oil pump 8; and a hydraulic circuit 10 for distributing working oil discharged from the mechanical oil pump 8 into a predetermined supply destination. The automatic transmission is configured to, in a key-on state, always supply working oil of the hydraulic circuit 10 to the intermittent mechanism 15 to generate fastening pressure of the intermittent mechanism 15, and in a key-off state, release the intermittent mechanism 15 to shut off transmission of power from the power transmission path to the mechanical oil pump 8.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control method and control device for an automatic transmission provided with a mechanical oil pump.

  Patent Document 1 discloses a drive device of a vehicle configured to be able to transmit power from drive wheels to a mechanically driven oil pump that is an accessory that requires rotational drive. Specifically, the power transmission path connecting the internal combustion engine, which is the drive source, and the drive wheels is provided with a power transmission mechanism capable of switching the rotational direction of the drive shaft relative to the output shaft of the internal combustion engine to forward or reverse direction. Furthermore, a belt transmission type accessory drive mechanism for transmitting the rotational power of the drive shaft to the oil pump is provided.

JP 2011-231844 A

  However, when the state in which the power from the drive wheels can be transmitted to the oil pump is maintained even when the key-off for stopping the internal combustion engine is maintained, for example, the power is transmitted to the oil pump via the drive shaft when the vehicle is pulled. As a result, the oil pump is operated even though it should be stopped, and the transmission oil is discharged. Here, in Patent Document 1, although an accessory clutch for disconnecting the power connection between the drive shaft (specifically, accessory drive mechanism) and the oil pump is provided, the accessory clutch at the key-off time is Nothing has been disclosed about control.

  It is an object of the present invention to provide a control method and control device for an automatic transmission which takes such problems into consideration.

  The present invention, in one form, is capable of interrupting the transmission of power from a power transmission path to a mechanical oil pump that receives power supply from a power transmission path connecting a drive source of a vehicle and a drive wheel. Abstract: A control method of an automatic transmission is provided, which controls an automatic transmission including a disconnection mechanism disposed and a hydraulic circuit that distributes hydraulic oil discharged by a mechanical oil pump to a predetermined supply destination. In the present embodiment, at key-on time, the hydraulic fluid of the hydraulic circuit is always supplied to the connection / disconnection mechanism to generate an engagement pressure of the connection / disconnection mechanism, and at the key-off time, the connection / disconnection mechanism is released. Shut off power transmission to the oil pump.

  The present invention provides, in another form, a control device for an automatic transmission.

  According to the present invention, the mechanical oil pump is driven by the power from the power transmission path at the key-on time, while the connection / disconnection mechanism is released at the key-off time to interrupt the transmission of power from the power transmission path to the mechanical oil pump. This makes it possible, for example, to prevent the mechanical oil pump from being driven by the power from the drive wheels when the vehicle is towed.

FIG. 1 is a schematic view showing a configuration of a vehicle drive system P including an automatic transmission TM1 according to an embodiment of the present invention. FIG. 2 is an explanatory view showing a state of the automatic transmission TM1 when the system is stopped (when the key is turned off). FIG. 3 is an explanatory view showing the state of the automatic transmission TM1 at the time of system operation (at the time of key-on). FIG. 4 is an explanatory view showing a state of the automatic transmission TM2 according to another embodiment of the present invention at the time of system operation (at key-on time).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Configuration of vehicle drive system)
FIG. 1 schematically shows the overall configuration of a vehicle drive system P provided with an automatic transmission TM1 according to an embodiment of the present invention.

  The vehicle drive system P includes an internal combustion engine (hereinafter simply referred to as "engine") 1 as a drive source, and includes a torque converter 2 and an automatic transmission TM1 on a power transmission path connecting the engine 1 and the left and right drive wheels 7. ing. In the present embodiment, the automatic transmission TM1 includes the forward and reverse switching mechanism 3 and the variator 4. However, it is also possible to configure the torque converter 2 as a part thereof. The automatic transmission TM 1 converts rotational power input from the engine 1 via the torque converter 2 at a predetermined gear ratio, and outputs the rotational power to the drive wheels 7 via the differential gear 5.

  The torque converter 2 includes a pump impeller 21 connected to the input shaft of the torque converter 2 and a turbine runner 22 connected to the output shaft of the torque converter 2, and the input rotational power is subjected to mechanical action of fluid. The power is transmitted to the output shaft. The torque converter 2 further includes a lockup clutch 23 connected to the output shaft, and the input shaft and the output shaft are directly coupled by engaging the lockup clutch 23 to reduce transmission loss due to fluid connection. It is possible. The engagement and release of the lockup clutch 23 can be switched by controlling the hydraulic pressure applied to the lockup clutch 23.

  The forward / reverse switching mechanism 3 is disposed between the torque converter 2 and the variator 4, and switches the direction of rotation of the output shaft with respect to the input shaft of the forward / reverse switching mechanism 3 to forward or reverse. Switch between forward and backward. The forward / reverse switching mechanism 3 includes a forward clutch 31 engaged when selecting the forward range, and a reverse brake 32 engaged when selecting the reverse range, and in the state where the forward clutch 31 is engaged, the vehicle is advanced to move backward. When the brake 32 is engaged, the vehicle is retracted. Whether the forward range is selected or the reverse range is selected is determined based on the position of the shift lever operated by the driver (hereinafter sometimes referred to as "shift position"). The forward / reverse switching mechanism 3 constitutes the “power cutoff mechanism” according to the present embodiment, and when the forward clutch 31 and the reverse brake 32 are both released, the automatic transmission TM1 is in the neutral state, The transmission switching mechanism 3, that is, the transmission of rotational power through the automatic transmission TM 1 is shut off. The operation of the forward / reverse switching mechanism 3 is controlled by adjusting the hydraulic pressure applied to the forward clutch 31 and the reverse brake 32.

  The variator 4 includes a primary pulley 41 and a secondary pulley 42, and also includes a belt 43 wound around the pulleys 41 and 42, and changes the ratio of the contact portion radius of the belt 43 in the primary pulley 41 and the secondary pulley 42. By changing the speed ratio, it is possible to change the transmission ratio steplessly. The rotational power input to the input shaft of variator 4 (in forward traveling, the rotational shaft of primary pulley 41) is converted according to the gear ratio, and the converted rotational power is output shaft of variator 4 (rotation of secondary pulley 42 Output through the axis). The transmission gear ratio of the variator 4 adjusts the hydraulic pressure (hereinafter sometimes referred to as "transmission pressure") applied to the movable sheave of the primary pulley 41 and the secondary pulley 42, and the V groove formed between the movable sheave and the fixed sheave It is controlled by changing the width of. In this embodiment, a value (= Npri / Nsec) obtained by dividing the number of revolutions Npri of the primary pulley 41 per unit time by the number of revolutions Nsec of the secondary pulley 42 is set as the transmission ratio of the variator 4.

  The rotational power output from the automatic transmission TM1 is transmitted to the drive shaft (in this embodiment, the wheel shaft) 6 via the final gear train and differential 5 set to a predetermined gear ratio, and rotates the drive wheels 7 Let

  In the present embodiment, the hydraulic pressure applied to the lockup clutch 23 of the torque converter 2, the fastening elements (forward clutch 31 and reverse brake 32) of the forward / reverse switching mechanism 3, and the transmission elements (primary pulley 41 and secondary pulley 42) of the variator 4 A mechanical oil pump 8 and an electric oil pump 9 are provided as a source of The mechanical oil pump 8 is configured to be drivable by the rotational power of the power transmission path connecting the engine 1 and the drive wheels 7, and is driven by the output of the engine 1 or the power from the drive wheels 7, and the automatic transmission TM1. The transmission oil or hydraulic oil stored in the oil pan of the above is boosted to a predetermined pressure and supplied to these parts via the hydraulic circuit 10. Here, the lockup clutch 23, the forward clutch 31, the reverse brake 32, the primary pulley 41 and the secondary pulley 42 correspond to the "supply destination" of the hydraulic oil according to the present embodiment. FIG. 1 shows the hydraulic oil supply path through the hydraulic circuit 10 by a dotted line with an arrow.

(Configuration and basic operation of control system)
The operations of the engine 1 and the automatic transmission TM1 are controlled by an engine controller 101 and a transmission controller 201, respectively. Each of these controllers 101 and 201 is configured as an electronic control unit, and is a microcomputer including a central processing unit (CPU), various storage devices such as a RAM and a ROM, an input / output interface, and the like.

  The engine controller 101 receives a detection signal from an operating state sensor that detects the operating state of the engine 1, executes a predetermined calculation based on the operating state, and determines the fuel injection amount, fuel injection timing, and ignition timing of the engine 1. Set etc.

  In this embodiment, as the driving state sensor, an accelerator sensor 111 for detecting an operation amount (hereinafter referred to as “accelerator opening degree”) APO of the accelerator pedal by the driver, a rotational speed sensor 112 for detecting the rotational speed NE of the engine 1, and an engine In addition to the coolant temperature sensor 113 for detecting the temperature TW of the coolant, an air flow meter, a throttle sensor, a fuel pressure sensor, an air-fuel ratio sensor, etc. (not shown) are provided.

  The transmission controller 201 is associated with the control of the automatic transmission TM1 and includes a vehicle speed sensor 211 for detecting a traveling speed (hereinafter referred to as "vehicle speed") VSP of the vehicle, and a brake depression force BPF indicating the depression amount of the brake pedal by the driver. Brake sensor 212 to detect, input side rotational speed sensor 213 to detect rotational speed of primary pulley 41 (means rotational speed Npri per unit time), rotational speed of secondary pulley 42 (means rotational speed Nsec per unit time) Acting on the output-side rotational speed sensor 214 that detects the pressure, the primary hydraulic pressure sensor 215 that detects the hydraulic pressure acting on the primary pulley 41 (this is the pressure in the oil chamber, hereinafter may be referred to as “primary hydraulic pressure”) Ppri, and the secondary pulley 42 Oil pressure (the pressure in the oil chamber, hereinafter referred to as “secondary oil pressure” There is a secondary oil pressure sensor 216 that detects Psec, an oil temperature sensor 217 that detects the temperature of the hydraulic fluid of the automatic transmission TM1 (hereinafter simply referred to as "oil temperature") Toil, and a shift position sensor 218 that detects the shift position SFT. Etc. are provided. In the present embodiment, the vehicle speed sensor 211 is provided to be able to measure the rotational speed of the drive shaft 6, and the transmission controller 201 calculates the vehicle speed VSP based on the detection signal of the vehicle speed sensor 211.

  The transmission controller 201 is communicably connected to the engine controller 101 via a CAN bus, and inputs information such as an accelerator opening APO as an operating state of the engine 1 from the engine controller 101.

  Then, the transmission controller 201 sets the target gear ratio of the automatic transmission TM1 (in the present embodiment, the variator 4) based on the operating conditions such as the accelerator opening APO and the vehicle speed VSP, and the actual gear ratio of the variator 4 The primary hydraulic pressure Ppri and the secondary hydraulic pressure Psec are controlled so as to approach the target gear ratio. Specifically, with the hydraulic pressure generated by the mechanical oil pump 8, in other words, with the discharge pressure of the mechanical oil pump 8 as the original pressure, predetermined working pressure or shift pressure acts on the primary pulley 41 and the secondary pulley 42 respectively. Control signals to various solenoids incorporated in the hydraulic circuit 10.

(Configuration of automatic transmission)
FIG. 2 shows a state of the automatic transmission TM1 according to the present embodiment at the time of system stop (at the time of key-off). The configuration of the automatic transmission TM1 will be further described with reference to the figure, focusing on the hydraulic system.

  The automatic transmission TM1 includes a mechanical oil pump 8 and an electric oil pump 9 as hydraulic pressure sources, and also includes a hydraulic circuit 10 for distributing the hydraulic oil discharged by the oil pumps 8 and 9 to the respective parts to which it is supplied. . The mechanical oil pump 8 and the electric oil pump 9 pump up the hydraulic oil of the automatic transmission TM1 from the oil pan and discharge the hydraulic oil at a pressure corresponding to the rotational speed. The hydraulic circuit 10 includes a plurality of solenoid valves and includes a plurality of oil passages. The hydraulic pressure is adjusted using the discharge pressure of the oil pumps 8 and 9 as a source pressure, and the hydraulic oil is supplied to each part at a predetermined pressure.

  The mechanical oil pump 8 operates by receiving power supply from a power transmission path connecting the engine 1 and the drive wheel 7 (FIG. 1), and operates the transmission oil or hydraulic oil stored in the oil pan to the hydraulic circuit 10 To the line pressure oil passage c1. The mechanical oil pump 8 is configured to be able to selectively receive power supply from a plurality of rotating parts in the power transmission path, and in the present embodiment, the forward / backward switching mechanism 3 which is a “power cutoff mechanism”. It is possible to selectively receive the supply of power from the first rotating portion closer to the engine 1 than the second rotating portion closer to the drive wheel 7.

  Specifically, the mechanical oil pump 8 receives rotational power of the pump impeller 21 of the torque converter 2 and receives rotational power of the rotation shaft of the primary pulley 41 (specifically, the rotation shaft of the fixed pulley). A belt (hereinafter referred to as "first belt") 82a is stretched between the pump impeller 21 and the input shaft of the pump main body 81, and a belt (hereinafter referred to as the following) between the primary pulley 41 and the input shaft of the pump main body 81. The transmission of power from the pump impeller 21 or the primary pulley 41 to the pump main body 81 is realized by using the first belt 82a or the second belt 82b as a medium. Here, the pump impeller 21 of the torque converter 2 corresponds to the “first rotation portion”, and the rotation axis of the primary pulley 41 corresponds to the “second rotation portion”.

  In order to enable selection of power, in the present embodiment, a first one-way clutch 83a is interposed between the first belt 82a for transmitting power from the pump impeller 21 and the input shaft of the pump body 81, A second one-way clutch 83 b is interposed between the second belt 82 b transmitting the power from the primary pulley 41 and the input shaft of the pump body 81. Each of the first one-way clutch 83a and the second one-way clutch 83b has an outer ring and an inner ring, and when the outer ring of the inner ring and the outer ring rotates fast, transmission of power from the belts 82a and 82b to the corresponding input shaft To block the transmission of power when the rotation of the inner ring is fast. As a result, mechanical oil pump 8 is driven by the power from the higher one of the rotational speeds of the input shaft among the rotary shafts of first and second rotary parts, that is, pump impeller 21 and primary pulley 41. It is driven.

  The electric oil pump 9 constitutes a hydraulic pressure source of the automatic transmission TM1 together with the mechanical oil pump 8. In the present embodiment, the electric oil pump 9 is provided in an auxiliary position of the mechanical oil pump 8. For example, the electric oil pump 9 raises the line pressure of the hydraulic circuit 10 when the engine 1 is stopped while the power is turned on by key-on, or when stopping after idle stop. It is driven to maintain a predetermined line pressure.

  The hydraulic circuit 10 includes a plurality of oil passages, specifically, a line pressure oil passage c1, a clutch pressure oil passage c2, a pilot pressure oil passage c31, c32, and a gear shift as oil passages through which hydraulic oil supplied to each part flows. It has pressure oil passages c41 and c42. Although the four types of oil passages c1 to c41 and c42 are illustrated for the sake of explanation, it goes without saying that oil passages other than these may be provided.

  The hydraulic oil of the original pressure discharged by the oil pumps 8 and 9 flows into the line pressure oil passage c1. A pressure regulating valve v1 is connected to the line pressure oil passage c1, and the hydraulic pressure of the line pressure oil passage c1 is regulated to a predetermined line pressure by the pressure regulating valve v1. The pressure regulator valve v1 has a variable valve body operating pressure or valve opening pressure. For example, in order to optimize the belt clamping force generated on the primary pulley 41, the valve body operating pressure is adjusted according to the accelerator opening APO. It is possible to change and adjust the line pressure. Further, a pressure reducing valve v2 is connected to the line pressure oil passage c1. In the present embodiment, the pressure reducing valve v2 is connected to the line pressure oil passage c1 between the primary hydraulic pressure control valve v51 and the secondary hydraulic pressure control valve v52.

  The hydraulic oil after pressure reduction by the pressure reducing valve v2 flows into the clutch pressure oil passage c2. The oil pressure of the clutch pressure oil passage c2 is adjusted to a predetermined clutch pressure lower than the line pressure by the pressure reducing valve v2. Two pilot valves, specifically, a first pilot valve v31 for primary oil pressure control and a second pilot valve v32 for secondary oil pressure control are connected to the clutch pressure oil passage c2. In the present embodiment, each of the first pilot valve v31 and the second pilot valve v32 is configured by an on / off solenoid valve. Further, a flow control valve v6 for switching between forward and reverse travel is connected to the clutch pressure oil passage c2. The flow control valve v6 is configured by a linear solenoid valve.

  The hydraulic fluid that has passed through the first pilot valve v31 or the second pilot valve v32 flows into the pilot pressure oil passages c31, c32. Here, for convenience, the oil passage extending from the first pilot valve v31 is referred to as a first pilot pressure oil passage c31, and the oil passage extending from the second pilot valve v32 is referred to as a second pilot pressure oil passage c32. The pressure of the first pilot pressure oil passage c31, in other words, the pilot pressure of the primary hydraulic pressure control valve v51, is adjusted by the first pilot valve v31, and the pressure of the second pilot pressure oil passage c32 by the second pilot valve v32, In other words, the pilot pressure of the secondary hydraulic control valve v52 is adjusted.

  The hydraulic oil after being controlled by the primary hydraulic pressure control valve v51 or the secondary hydraulic pressure control valve v52 flows into the shift pressure oil paths c41 and c42. The hydraulic pressure of the first transmission pressure oil passage c41 communicating with the pulley oil chamber (hereinafter referred to as "primary oil chamber") of the primary pulley 41 according to the gear ratio by the primary hydraulic control valve v51 operating according to the pilot pressure It is adjusted to a predetermined shift pressure. Thereby, a predetermined pulley thrust acts on the movable pulley of the primary pulley 41. Here, “pulley thrust” means the product of the pressure or the shift pressure of the pulley oil chamber multiplied by the effective area of the pressure receiving surface formed on the target movable pulley. On the other hand, the secondary hydraulic pressure control valve v52 operates according to the pilot pressure, whereby the hydraulic pressure of the second transmission pressure oil passage c42 communicating with the pulley oil chamber of the secondary pulley 42 (hereinafter referred to as "secondary oil chamber") It is adjusted to the predetermined shift pressure according to. Thereby, a predetermined pulley thrust acts on the movable pulley of the secondary pulley 42. By controlling the difference or ratio between the pulley thrust for the primary pulley 41 and the pulley thrust for the secondary pulley 42, it is possible to change the transmission ratio of the automatic transmission TM1.

  The hydraulic oil after being controlled by the flow control valve v6 for forward / reverse switching is supplied to the forward clutch 31 or the reverse brake 32 by switching the oil path by the manual valve 11 linked to the shift lever. In FIG. 2 (also in FIGS. 3 and 4), hydraulic cylinders 31s, 32s for driving the forward clutch 31 or the reverse brake 32 are conceptually shown. When the oil passage leading to one hydraulic cylinder 31s is set, the forward clutch 31 is engaged to enable the vehicle to move forward, and when the oil passage leading to the other hydraulic cylinder 32s is set, the reverse brake is set. 32 is engaged to allow the vehicle to move backward. On the other hand, in a state in which the communication between the clutch pressure oil passage c2 and the hydraulic cylinders 31s and 32s is shut off via the flow control valve v6, hydraulic fluid is discharged from the hydraulic cylinders 31s and 32s, and the forward brake 31 and the reverse brake 32 Both are released, and the automatic transmission TM1 is in the neutral state.

  The transmission oil that has passed through the pressure regulating valve v1 and a portion of the transmission oil that has passed through the pressure reducing valve v2 are supplied to the torque converter 2 via the low pressure circuit 12 as hydraulic oil for the lockup clutch 23. It is supplied to the lubrication system and cooling system of the machine TM1.

  In addition to the above, in the present embodiment, the connection / disconnection mechanism 15 is provided between the mechanical oil pump 8 and the power transmission path that is an acquisition source of the power thereof, and the power transmission path is specifically The transmission of the power to the mechanical oil pump 8 can be cut off from the side closer to the drive wheel 7 than the forward / reverse switching mechanism 3 which is the “power cut-off mechanism”. In the present embodiment, the connection / disconnection mechanism 15 is configured as a friction clutch 15 having a pair of friction plates as a fastening element, and when the friction clutch 15 is engaged, the input of the pump main body 81 from the second belt 82 b Transmission of power to the shaft becomes possible, and in a state in which this is released, transmission of power from the second belt 82b to the input shaft of the pump main body 81 is interrupted. The connection / disconnection mechanism 15 is not limited to the friction clutch, but may be configured as various hydraulic clutches that can be driven by oil pressure, for example, a meshing clutch.

  The hydraulic pressure for engaging the friction clutch 15 is adjusted based on the pressure after discharge by the mechanical oil pump 8 or the electric oil pump 9 which is a hydraulic pressure source of the automatic transmission TM1. In the present embodiment, the oil passage of the hydraulic circuit 10 and the hydraulic cylinder 15s of the friction clutch 15, specifically, the clutch pressure oil passage c2 and the hydraulic cylinder 15s are connected via the engagement pressure oil passage c5 having no inherent pressure control means. The transmission oil after pressure reduction by the pressure reducing valve v2 is supplied to the hydraulic cylinder 15s of the friction clutch 15. In other words, in the present embodiment, the clutch pressure oil passage c2 and the oil chamber of the hydraulic cylinder 15s are always in communication with each other via the engagement pressure oil passage c5.

(Description of operation)
Hereinafter, the operation of the automatic transmission TM1 according to the present embodiment will be described with reference to FIGS. 2 and 3, focusing on the hydraulic system.

  FIG. 2 shows the state of the automatic transmission TM1 at system stop (key off), and FIG. 3 shows the state of the automatic transmission TM1 at system operation (key on).

  In the key-off state (at the time of key-off) in which the power supply to the vehicle drive system P (specifically, the engine controller 1 and the transmission controller 201) is cut off, as shown in FIG. By setting the position to the non-driving range (for example, the P range), both the forward clutch 31 and the reverse brake 32 of the forward / reverse switching mechanism 3 are released, and the automatic transmission TM1 is in the neutral state. Furthermore, since the vehicle is stopped and the engine 1 is also stopped, both the mechanical oil pump 8 and the electric oil pump 9 are stopped, and the necessary clamping pressure can not be obtained due to the pressure drop in the hydraulic cylinder 15s. Therefore, the friction clutch 15 which is a "connection / disengagement mechanism" is in a released state.

  When the start switch 219 is turned on to enter the key-on state (at the key-on) where the power is turned on, as shown in FIG. 3, the supply of fuel to the engine 1 is started, and the engine 1 is started. As a result, the pump impeller 21 of the torque converter 2 is rotated, the rotational power of the pump impeller 21 is transmitted to the input shaft of the pump main body 81 via the first belt 82a, and the mechanical oil pump 8 is driven. Here, the transmission of power from the pump impeller 21 to the input shaft is permitted by the first one-way clutch 83a because the vehicle is stopped. When the pressure in the line pressure oil passage c1 is increased by the operation of the mechanical oil pump 8, the pressure increase is transmitted to the hydraulic cylinder 15s through the clutch pressure oil passage c2 and the engagement pressure oil passage c5 (a state where the pressure is transmitted Is indicated conceptually by a thick line), a fastening pressure is generated, and the friction clutch 15 is engaged. Then, while the pressure in the line pressure oil passage c1 is maintained, the engagement pressure is also maintained, and the friction clutch 15 maintains the engaged state.

  Thereafter, when the shift position is switched to the travel range (for example, D range or R range), the hydraulic oil controlled by the flow control valve v6 is supplied to the forward clutch 31 or the reverse brake 32 through the manual valve 11. The vehicle can be advanced or retracted by the driving force of the engine 1. Furthermore, the transmission controller 201 sets the target gear ratio according to the operating conditions such as the vehicle speed VSP and the accelerator opening APO, and the pilot valves v31, v32 and hydraulic control so that the actual transmission approaches the target gear ratio. The valves v51 and v52 are controlled, and the relative value (for example, the ratio of the pulley thrust) of the pulley thrust of the primary pulley 41 and the pulley thrust of the secondary pulley 42 is adjusted.

  As described above, at the key-on time, the friction clutch 15 is engaged, so that the mechanical oil pump 8 can be driven not only by the power from the engine 1 but also by the power from the drive wheels 7. It is possible. Therefore, the discharge pressure of the mechanical oil pump 8 not only at the time of driving travel where the driving force is actually generated by the engine 1 but also at the time of sailing traveling where the inertia travel is performed with the engine 1 stopped by the fuel cut. And maintain the necessary line pressure.

  When the start switch 219 is turned off after stopping the vehicle and the power supply to the vehicle drive system P is cut off again (FIG. 2), the transmission of power from the engine 1 is stopped with the stop of the engine 1, The mechanical oil pump 8 stops. As a result, the source pressure is lost, and when the pressure in the line pressure oil passage c1 decreases, the pressure in the hydraulic cylinder 15s also decreases, and the friction clutch 15 is released again.

(Description of function and effect)
The automatic transmission TM1 according to the present embodiment is configured as described above, and the effects obtained by the present embodiment will be described below.

  First, at the time of key-on, the mechanical oil pump 8 can be driven by the power from the power transmission path by engaging the friction clutch 15 which is a “connection / disconnection mechanism”. On the other hand, when the key is off, the friction clutch 15 is released, and the transmission of the power from the power transmission mechanism to the mechanical oil pump 8 is shut off. When the vehicle is towed, the mechanical oil pump 8 is driven by the power from the drive wheels 7 and operates on the hydraulic circuit 10 of the automatic transmission TM1 and various hydraulic elements (for example, primary pulley 41 and secondary pulley 42 as speed change elements). It becomes possible to avoid that oil is supplied. Thereby, for example, an excessive temperature rise of the hydraulic oil can be avoided. And since release of the friction clutch 15 is made according to the fall of the motive power from the power transmission mechanism by a key-off without using a special actuator or a solenoid, it is possible to exhibit the above effect while suppressing an increase in the number of parts. It is possible.

  Here, by making the clearance at the time of release of the friction clutch 15 larger than that set for a general friction clutch, the transmission of power from the drive wheel 7 is more reliably interrupted, and the mechanical type at the key-off time It is possible to avoid the rotation of the oil pump 8. In this embodiment, as such a clearance, a clearance larger than the clearance at the time of the neutral position of the forward clutch 31 and the reverse brake 32 of the forward / reverse switching mechanism 3 is adopted. Furthermore, when the friction clutch 15 is wet, the temperature of the working oil is low, and even if the viscosity is high, a clearance that does not cause corotation according to the movement of the drive side element to the friction plate which is the driven side element. By doing this, it is possible to avoid the rotation of the mechanical oil pump 8 even when being pulled in an environment where the outside air temperature is extremely low.

  Second, the first rotating portion (for example, the pump impeller 21 of the torque converter 2) closer to the engine 1 than the forward / reverse switching mechanism 3 which is the “power cutoff mechanism” (for example, the second rotating portion (for example, By configuring the mechanical oil pump 8 to be selectively drivable by the power from the faster rotating one of the primary pulley 41 and the rotational shaft of the primary pulley 41, the mechanical oil pump 8 can be operated safely during driving travel. It is possible to maintain the line pressure by operating the mechanical oil pump 8 even while traveling to shut off the transmission of power via the power transmission path, for example, while sailing with the automatic transmission TM1 in neutral. .

  Here, by adopting the one-way clutches 83a and 83b, it is possible to easily realize a configuration in which the mechanical oil pump 8 can be selectively driven by the power from the faster one of the first and second rotating parts. Can.

  Thirdly, in addition to the mechanical oil pump 8 as the hydraulic pressure source of the automatic transmission TM1, the hydraulic circuit 10 is provided when the mechanical oil pump 8 is stopped by providing the electric oil pump 9 disposed in parallel with this. It is possible to maintain the line pressure by securing the original pressure of Furthermore, since the hydraulic oil can be supplied by the electric oil pump 9 and the engagement pressure can be maintained at the idle stop for automatically stopping the engine 1 in the key-on state, the engagement state of the friction clutch 15 at the idle stop To prepare for re-start after the idle stop is released.

  Fourth, the pressure of the hydraulic oil supplied to the friction clutch 15 can be suppressed to a low level by supplying the hydraulic oil after pressure reduction by the pressure regulating valve v1 to the friction clutch 15, and parts required for holding the hydraulic pressure For example, it is possible to increase the degree of freedom of selection of the engagement pressure oil passage c5 or the hydraulic cylinder 15s, and to miniaturize the device. Here, the above effect can be more remarkably exhibited by supplying the hydraulic oil further decompressed by the pressure reducing valve v2 after reducing the pressure by the pressure regulating valve v1.

  The oil passage of the hydraulic circuit 10 connecting the engagement pressure oil passage c5 is not limited to the oil passage (in the present embodiment, the clutch pressure oil passage c2) through which the hydraulic oil after pressure reduction by one pressure reducing valve v2 flows. . It is also possible to supply the hydraulic oil decompressed by the plurality of pressure reducing valves v21 and v22 after reducing the pressure by the pressure regulating valve v1.

  FIG. 4 shows the state of the automatic transmission TM2 according to another embodiment of the present invention at the time of system operation (at key-on). Thus, in the one provided with the plurality of pressure reducing valves v21 and v22 on the downstream side of the pressure regulating valve v1, the engagement pressure oil path c5 is connected to the oil passage on the downstream side of the two or more pressure reducing valves v21 and v22, and the friction clutch Lower pressure hydraulic oil may be supplied to 15.

  In the above description, the one-way clutches (the first one-way clutch 83a and the second one-way clutch 83b) are installed around the rotary shaft of the mechanical oil pump 8. However, the present invention is not limited to this. It is also possible. For example, the first one-way clutch 83 a is installed coaxially with the pump impeller 21 of the torque converter 2.

  Furthermore, the automatic transmission to which the present invention is applied is provided with an auxiliary transmission mechanism on the downstream side closer to the drive wheels 7 than the variator 4 with the variator 4 as the main transmission mechanism instead of the forward / reverse switching mechanism 3 May be Here, the “power cutoff mechanism” can be provided not only on the upstream side closer to the engine 1 than the variator 4 but also on the downstream side, and in that case, it can be incorporated into the auxiliary transmission mechanism.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can say that a various change and correction can be made within the range described in the claim. It's too late.

P: Vehicle drive system TM1, TM2: Automatic transmission 1: Internal combustion engine 2 ... Torque converter 21: Pump impeller 22: Turbine runner 23: Lock-up clutch 3 ... Forward / backward switching mechanism 31: Forward clutch 32: Reverse brake 4 ... Variator 41 Primary pulley 42 Secondary pulley 43 Belt 5 Differential gear 6 Drive shaft (wheel shaft)
7 ... driving wheel 8 ... mechanical oil pump 9 ... electric oil pump 10 ... hydraulic circuit 15 ... friction clutch 15s ... hydraulic cylinder 101 ... engine controller 201 ... transmission controller

Claims (8)

A mechanical oil pump supplied with power from a power transmission path connecting a drive source of the vehicle and the drive wheels;
A disconnection mechanism disposed so as to be able to interrupt transmission of power from the power transmission path to the mechanical oil pump;
A hydraulic circuit that distributes hydraulic oil discharged by the mechanical oil pump to a predetermined supply destination;
A method of controlling an automatic transmission comprising:
At the time of key-on, the hydraulic fluid of the hydraulic circuit is always supplied to the connection / disconnection mechanism to generate an engagement pressure of the connection / disconnection mechanism,
At key-off time, the connection mechanism is released to interrupt the transmission of power from the power transmission path to the mechanical oil pump.
Control method of automatic transmission. When the key is turned on, hydraulic oil of the hydraulic circuit is supplied to the connection / disconnection mechanism via an oil passage connected between the hydraulic circuit and the connection / disconnection mechanism.
A control method of an automatic transmission according to claim 1. The control method of an automatic transmission according to claim 1 or 2, further comprising a pressure regulating valve for reducing the pressure of the hydraulic fluid after the discharge in the hydraulic circuit.
Supplying the hydraulic oil after pressure reduction by the pressure regulator to the connection / disconnection mechanism at the time of the key-on;
Control method of automatic transmission. 4. The control method of an automatic transmission according to claim 3, further comprising a pressure reducing valve for reducing the hydraulic oil after pressure reduction by the pressure adjusting valve in the hydraulic circuit.
Supplying the hydraulic oil after pressure reduction by the pressure reducing valve to the connection / disconnection mechanism at the time of the key-on;
Control method of automatic transmission. The control method of an automatic transmission according to any one of claims 1 to 4, wherein the power transmission path is provided with a power shutoff mechanism disposed to be able to shut off transmission of power in the power transmission path. ,
The clearance at the time of release of the connection / disconnection mechanism is larger than the clearance at the time of release of the power shutoff mechanism,
Control method of automatic transmission. The control method of an automatic transmission according to claim 5, wherein the connection / disconnection mechanism is a wet clutch.
The clearance at the time of release of the connection and disconnection mechanism is a clearance at which the driven side element of the connection and disconnection mechanism does not generate corotation according to the movement of the drive side element of the connection and disconnection mechanism at extremely low temperature.
A control method of an automatic transmission according to claim 5. A mechanical oil pump supplied with power from a power transmission path connecting a drive source of the vehicle and the drive wheels;
A disconnection mechanism disposed so as to be able to interrupt transmission of power from the power transmission path to the mechanical oil pump;
A hydraulic circuit that distributes hydraulic oil discharged by the mechanical oil pump to a predetermined supply destination;
Equipped with
At the time of key-on, the hydraulic fluid of the hydraulic circuit is always supplied to the connection / disconnection mechanism to generate an engagement pressure of the connection / disconnection mechanism,
At key-off time, the connection mechanism is released to interrupt the transmission of power from the power transmission path to the mechanical oil pump.
Control unit of automatic transmission. The power transmission path includes a power shut-off mechanism disposed to be able to shut off transmission of power in the power transmission path,
The mechanical oil pump is a rotary unit on the power transmission path, and among the first rotary unit closer to the drive source than the power shutoff mechanism and the second rotary unit closer to the drive wheel, rotation is possible. It can be selectively driven by the power from the faster one,
The connection / disconnection mechanism is disposed so as to be capable of blocking the transmission of power from the second rotating portion of the power transmission path to the mechanical oil pump.
The control device of an automatic transmission according to claim 7.

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