JP2017082817A - Control device of power transmission device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmission efficiency of a continuously variable transmission.SOLUTION: A hydraulic switch 88 whose operation state is switched at the necessary lowest pressure Pinlim of a primary pulley 66 is arranged in an oil passage 86 for supplying primary pressure Pin to the primary pulley 66, a hydraulic pressure control command signal Scvt (that is, a drive current of an electromagnetic valve SLP) of the primary pressure Pin is changed so as to vary the primary pressure Pin in a prescribed low-pressure region, and the hydraulic pressure control command signal Scvt when the switching of an operation state of the hydraulic switch 88 is detected is set as the lowest pressure assurance current A being an indication value corresponding to the necessary lowest pressure Pinlim, thus controlling the primary pressure Pin with the lowest pressure assurance current A as a reference. By this constitution, it is not necessary to set the primary pressure Pin on design to a high-pressure side by taking into consideration an individual variation of parts in the hydraulic pressure control circuit 80. The transmission efficiency of a continuously variable transmission 24 is thereby improved.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a control device for a vehicle power transmission device including a continuously variable transmission of a type in which a transmission element is wound between pulleys.

  A continuously variable transmission having a primary pulley, a secondary pulley, and a transmission element (e.g., belt, chain) wound around each of the pulleys for transmitting the power of the driving force source to the driving wheel, and 2. Description of the Related Art A vehicle power transmission device including a hydraulic control circuit that supplies pulley hydraulic pressure is well known. For example, it is a continuously variable transmission described in Patent Document 1. In such a continuously variable transmission, each pulley has a fixed sheave and a movable sheave. The movement of the movable sheave in the axial direction changes the pulley groove width, changes the gear ratio, and the primary pulley. By setting the groove width to the maximum, the maximum transmission gear ratio (that is, the lowest transmission gear ratio on the lowest vehicle speed side (low side)) is set. Therefore, it is not necessary to apply the primary pulley hydraulic pressure to the primary pulley in order to set the speed ratio of the continuously variable transmission to the maximum speed ratio. However, if the hydraulic pressure is applied from a state where the primary pulley hydraulic pressure is not applied, the groove width of the primary pulley cannot be quickly reduced. On the other hand, in Patent Document 1, when the rotation sensor value is less than a predetermined value so that the calculation accuracy of the transmission ratio of the continuously variable transmission is low, the primary pulley hydraulic pressure is set to the maximum transmission ratio. It is disclosed that the lower limit hydraulic pressure can be set.

International Publication No. 2011/114488

  By the way, in consideration of preventing the transmission element from slipping, it is necessary to guarantee the minimum primary pulley hydraulic pressure (hereinafter, the minimum pressure is referred to as the required minimum pressure). There are individual variations in components in the hydraulic control circuit that supplies the primary pulley hydraulic pressure. Therefore, the characteristics of the actual value with respect to the indicated value of the primary pulley hydraulic pressure also vary. In order to ensure the required minimum pressure even if the actual value of the primary pulley hydraulic pressure becomes low due to variations, it is necessary to set the designed primary pulley hydraulic pressure to the high pressure side. Then, it is necessary to set the secondary pulley hydraulic pressure high, and the transmission efficiency of the continuously variable transmission may be reduced.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a control device for a vehicle power transmission device capable of improving the transmission efficiency of a continuously variable transmission. is there.

  The gist of the first invention is that (a) a continuously variable transmission having a primary pulley, a secondary pulley, and a transmission element wound around each pulley, and transmitting the power of the driving force source to the driving wheel side. And a control device for a vehicle power transmission device comprising a hydraulic control circuit that supplies each pulley oil pressure to each pulley, wherein (b) the vehicle power transmission device is a primary pulley to the primary pulley. A hydraulic switch configured to switch an operating state at a minimum required pressure of the primary pulley, which is set in advance to prevent slippage of the transmission element, in an oil passage for supplying hydraulic pressure; and (c) the primary pulley The instruction value of the primary pulley oil pressure is changed so that the oil pressure fluctuates in a predetermined low pressure region, and the instruction value when the change of the operation state of the oil pressure switch is detected is the required value. It lies in including minimum pressure determination unit to be set as an instruction value corresponding to a low pressure.

  According to the first aspect of the present invention, the oil passage that supplies the primary pulley hydraulic pressure to the primary pulley is provided with the hydraulic switch that can switch the operation state at the minimum required pressure of the primary pulley, and the primary pulley hydraulic pressure is reduced to a predetermined low pressure. The instruction value of the primary pulley oil pressure is changed so as to vary in the region, and the instruction value when the change of the operation state of the hydraulic switch is detected is set as the instruction value corresponding to the necessary minimum pressure. The primary pulley hydraulic pressure can be controlled based on the corresponding indicated value. Accordingly, it is not necessary to set the designed primary pulley hydraulic pressure on the high pressure side in consideration of individual variations of components in the hydraulic control circuit. That is, the necessary minimum pressure of the primary pulley can be guaranteed without setting the designed primary pulley hydraulic pressure to the high pressure side. Therefore, the transmission efficiency of the continuously variable transmission can be improved.

It is a figure explaining the schematic structure of the vehicle to which the present invention is applied. It is a figure for demonstrating the switching of the driving modes of the vehicle power transmission device. It is a figure explaining the principal part of the control function and various control systems for various control in vehicles. It is a figure explaining the part which controls the hydraulic pressure regarding a continuously variable transmission, a 1st clutch, a 2nd clutch, and a meshing type clutch among hydraulic control circuits. It is a figure which shows an example of the operating state of a hydraulic switch, and the characteristic of a primary pressure. It is a flowchart explaining the principal part of the control action of an electronic control unit, ie, the control action for improving the transmission efficiency of a continuously variable transmission. It is a figure which shows an example which sets the design value of a primary pressure to the high voltage | pressure side with respect to the dispersion | variation in the characteristic of a primary pressure, Comprising: It is a figure explaining the conventional method.

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

  FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied. In FIG. 1, a vehicle 10 is provided in an engine 12 such as a gasoline engine or a diesel engine that functions as a driving power source for traveling, a driving wheel 14, and a power transmission path between the engine 12 and the driving wheel 14. And a vehicle power transmission device 16 (hereinafter referred to as a power transmission device 16). The power transmission device 16 is connected to a known torque converter 20 as a fluid transmission device connected to the engine 12, an input shaft 22 connected to the torque converter 20, and an input shaft 22 in a housing 18 as a non-rotating member. A known belt-type continuously variable transmission 24 serving as a continuously variable transmission, a forward / reverse switching device 26 connected to the input shaft 22, and a continuously variable transmission connected to the input shaft 22 via the forward / reverse switching device 26. A gear transmission mechanism 28 serving as a gear transmission provided in parallel with the transmission 24, an output shaft 30, which is a common output rotation member of the continuously variable transmission 24 and the gear transmission mechanism 28, a counter shaft 32, an output shaft 30, and a counter A reduction gear device 34 composed of a pair of gears which are provided on the shaft 32 so as not to rotate relative to each other and meshed with each other, and a gear 36 provided on the counter shaft 32 so as not to rotate relatively. Differential gear 38, and a axle 40 or the like of the pair coupled to a differential gear 38. In the power transmission device 16 configured as described above, the power of the engine 12 (the torque and the force are synonymous unless otherwise specified) is transmitted from the torque converter 20, the continuously variable transmission 24 (or the forward / reverse switching device 26 and the gear transmission mechanism). 28), the reduction gear device 34, the differential gear 38, the axle 40 and the like are sequentially transmitted to the pair of drive wheels 14.

  As described above, the power transmission device 16 transmits the power of the engine 12 to the engine 12 (here, the input shaft 22 which is an input rotating member to which the power of the engine 12 is transmitted) and the driving wheel 14 (here, the driving wheel 14 is transmitted). A gear transmission mechanism 28 and a continuously variable transmission 24 are provided in parallel with the power transmission path PT between the output shaft 30 as an output rotating member and the output. Therefore, the power transmission device 16 transmits a power of the engine 12 from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the gear transmission mechanism 28 (hereinafter referred to as a first power transmission path PT1). ) And a power transmission path (hereinafter referred to as a second power transmission path PT2) for transmitting the power of the engine 12 from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the continuously variable transmission 24. The power transmission path PT is provided in parallel between the input shaft 22 and the output shaft 30. The power transmission device 16 is switched between the first power transmission path PT1 and the second power transmission path PT2 in accordance with the traveling state of the vehicle 10. Therefore, the power transmission device 16 includes a plurality of engagement devices that selectively switch the power transmission path PT between the first power transmission path PT1 and the second power transmission path PT2. The engagement device includes an engagement device that connects and disconnects the first power transmission path PT1 (in other words, an engagement device that is engaged to form the first power transmission path PT1) and the first clutch C1. It includes a brake B1 and a second clutch C2 that is an engagement device that connects and disconnects the second power transmission path PT2 (in other words, an engagement device that is engaged to form the second power transmission path PT2). Yes. The first clutch C1, the first brake B1, and the second clutch C2 correspond to a connection / disconnection device, and all of them are known hydraulic wet friction engagement devices (frictions) that are frictionally engaged by a hydraulic actuator. Clutch). Further, each of the first clutch C1 and the first brake B1 is one of the elements constituting the forward / reverse switching device 26, as will be described later.

  The torque converter 20 is interposed in a power transmission path between the engine 12 and the input shaft 22, and is provided around the input shaft 22 and coaxially with the input shaft 22. The torque converter 20 includes a pump impeller 20p connected to the engine 12 and a turbine impeller 20t connected to the input shaft 22, and transmits the power of the engine 12 to the input shaft 22. The torque converter 20 includes a known lock-up clutch Clu that can be directly connected between the pump impeller 20p and the turbine impeller 20t, that is, between the input / output rotating members of the torque converter 20. The power transmission device 16 includes a mechanical oil pump 42 connected to the pump impeller 20p. The oil pump 42 is rotationally driven by the engine 12 to control shift of the continuously variable transmission 24, operate the plurality of engaging devices, supply lubricating oil to each part of the power transmission device 16, and the like. To generate (discharge) hydraulic pressure.

  The forward / reverse switching device 26 is provided coaxially with the input shaft 22 around the input shaft 22 in the first power transmission path PT1, and includes a double pinion planetary gear device 26p, a first clutch C1, and a first clutch C1. One brake B1 is provided. The planetary gear device 26p is a differential mechanism having three rotating elements: a carrier 26c as an input element, a sun gear 26s as an output element, and a ring gear 26r as a reaction force element. The carrier 26c is integrally connected to the input shaft 22, the ring gear 26r is selectively connected to the housing 18 via the first brake B1, and the sun gear 26s is coaxial with the input shaft 22 around the input shaft 22. It is connected to a small-diameter gear 44 provided so as to be relatively rotatable. The carrier 26c and the sun gear 26s are selectively connected via the first clutch C1. Therefore, the first clutch C1 is an engagement device that selectively connects two of the three rotating elements, and the first brake B1 selectively connects the reaction element to the housing 18. It is an engaging device to do.

  The gear transmission mechanism 28 includes a small-diameter gear 44 and a large-diameter gear 48 that is provided around the gear mechanism counter shaft 46 so as not to rotate relative to the gear mechanism counter shaft 46 and meshes with the small-diameter gear 44. ing. The gear transmission mechanism 28 includes an idler gear 50 provided around the gear mechanism counter shaft 46 so as to be relatively rotatable coaxially with the gear mechanism counter shaft 46, and the output shaft 30 with respect to the output shaft 30. An output gear 52 that is provided on the coaxial center so as not to rotate relative to the idler gear 50 is provided. The output gear 52 has a larger diameter than the idler gear 50. Therefore, the gear transmission mechanism 28 has a single gear ratio (gear stage, gear stage) as a predetermined speed ratio (gear stage, gear stage) in the power transmission path PT between the input shaft 22 and the output shaft 30. It is a transmission mechanism to be formed. The gear transmission mechanism 28 further includes a meshing clutch D1 that is provided between the large-diameter gear 48 and the idler gear 50 around the gear mechanism counter shaft 46, and selectively connects and disconnects between these gears. The meshing clutch D1 is disposed in a power transmission path PT between the forward / reverse switching device 26 (here, the first clutch C1 also agrees) and the output shaft 30 (in other words, the output shaft is more than the first clutch C1). 30), which functions as a third clutch that connects and disconnects the first power transmission path PT1 (in other words, the third clutch that forms the first power transmission path PT1 by being engaged with the first clutch C1). And is included in the plurality of engaging devices.

  Specifically, the meshing clutch D1 includes a clutch hub 54 provided around the gear mechanism counter shaft 46 so as not to rotate relative to the gear mechanism counter shaft 46, an idler gear 50, and a clutch hub 54. A clutch gear 56 disposed between and fixed to the idler gear 50 is spline-fitted to the clutch hub 54 so that the gear mechanism counter shaft 46 cannot rotate relative to the shaft center and is parallel to the shaft center. And a cylindrical sleeve 58 provided so as to be relatively movable in various directions. The sleeve 58 that is always rotated integrally with the clutch hub 54 is moved to the clutch gear 56 side and meshed with the clutch gear 56, whereby the idler gear 50 and the gear mechanism counter shaft 46 are connected. Further, the meshing clutch D1 includes a known synchromesh mechanism S1 as a synchronizing mechanism that synchronizes rotation when the sleeve 58 and the clutch gear 56 are engaged. In the meshing clutch D1 configured as described above, the fork shaft 60 is operated by the hydraulic actuator 62, whereby the sleeve 58 is connected to the shaft of the gear mechanism counter shaft 46 via the shift fork 64 fixed to the fork shaft 60. It is slid in a direction parallel to the center, and the engaged state and the released state are switched.

  The first power transmission path PT1 is formed by engaging the meshing clutch D1 and the first clutch C1 (or the first brake B1) provided closer to the input shaft 22 than the meshing clutch D1. . A forward power transmission path is formed by the engagement of the first clutch C1, and a reverse power transmission path is formed by the engagement of the first brake B1. In the power transmission device 16, when the first power transmission path PT <b> 1 is formed, the power transmission state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the gear transmission mechanism 28 is set. The On the other hand, the first power transmission path PT1 is in a neutral state (power transmission) that interrupts power transmission when at least the first clutch C1 and the first brake B1 are both released or at least the meshing clutch D1 is released. It is said that it is in a shut-off state

  The continuously variable transmission 24 includes a primary pulley 66 having a variable effective diameter provided on the input shaft 22, a secondary pulley 70 having a variable effective diameter provided on a rotary shaft 68 coaxial with the output shaft 30, and each of these. A transmission belt 72 as a transmission element wound between the pulleys 66 and 70, and a frictional force between the pulleys 66 and 70 and the transmission belt 72 (a clamping pressure is also agreed; also referred to as a belt clamping pressure). Is a belt-type continuously variable transmission mechanism that transmits power through the power transmission of the engine 12 to the drive wheel 14 side.

  The primary pulley 66 includes a fixed sheave 66a coupled to the input shaft 22, a movable sheave 66b provided so as not to rotate relative to the fixed sheave 66a around the axis of the input shaft 22 and to move in the axial direction. And a hydraulic actuator 66c that applies a primary thrust Win (= primary pressure Pin × pressure receiving area) in the primary pulley 66 for changing the V groove width between the sheaves 66a and 66b. The secondary pulley 70 includes a fixed sheave 70a connected to the rotary shaft 68, and a movable sheave 70b provided so as not to be rotatable relative to the fixed sheave 70a around the axis of the rotary shaft 68 and to be movable in the axial direction. And a hydraulic actuator 70c for applying a secondary thrust Wout (= secondary pressure Pout × pressure receiving area) in the secondary pulley 70 for changing the V groove width between the sheaves 70a and 70b. The primary pressure Pin is a primary pulley hydraulic pressure supplied to the hydraulic actuator 66c by a hydraulic control circuit 80 (see FIG. 3) provided in the power transmission device 16, and the secondary pressure Pout is supplied to the hydraulic actuator 70c by the hydraulic control circuit 80. This is the secondary pulley hydraulic pressure to be supplied. The oil pressures Pin and Pout are pulley oil pressures that generate thrusts Win and Wout that press the movable sheaves 66b and 70b toward the fixed sheaves 66a and 70a, respectively.

  In the continuously variable transmission 24, the primary pressure Pin and the secondary pressure Pout are respectively regulated by the hydraulic control circuit 80 driven by the electronic control unit 90 (see FIG. 3), so that the primary thrust Win and the secondary thrust Wout are reduced. Each is controlled. As a result, the V-groove widths of the pulleys 66 and 70 are changed, the engagement diameter (effective diameter) of the transmission belt 72 is changed, and the transmission gear ratio γcvt (= primary pulley rotation speed Npri / secondary pulley rotation speed Nsec) is changed. In addition, the frictional force between the pulleys 66 and 70 and the transmission belt 72 is controlled so that the transmission belt 72 does not slip. That is, by controlling the primary pressure Pin (the primary thrust Win is also agreed) and the secondary pressure Pout (the secondary thrust Wout is also agreed), the actual transmission ratio is prevented while the transmission belt 72 is prevented from slipping (hereinafter referred to as belt slip). γcvt is set as the target gear ratio γtgt.

  In the continuously variable transmission 24, for example, when the primary pressure Pin is increased, the V groove width of the primary pulley 66 is narrowed to reduce the speed ratio γcvt, that is, the continuously variable transmission 24 is upshifted. When the primary pressure Pin is lowered, the V groove width of the primary pulley 66 is widened to increase the gear ratio γcvt, that is, the continuously variable transmission 24 is downshifted. Therefore, when the V-groove width of the primary pulley 66 is minimized, the minimum transmission ratio γmin (maximum vehicle speed side transmission ratio, maximum Hi) is formed as the transmission ratio γcvt of the continuously variable transmission 24. Further, when the V-groove width of the primary pulley 66 is maximized, the maximum transmission ratio γmax (minimum vehicle speed side transmission ratio, lowest) is formed as the transmission ratio γcvt of the continuously variable transmission 24. In addition, while the belt slippage is prevented by the primary pressure Pin and the secondary pressure Pout, the target gear ratio γtgt is realized by the mutual relationship between the primary thrust Win and the secondary thrust Wout. The target shift is not realized only by (consent).

  The output shaft 30 is disposed around the rotation shaft 68 so as to be rotatable relative to the rotation shaft 68 coaxially. The second clutch C2 is provided on the drive wheel 14 (here, the output shaft 30 also agrees) side of the continuously variable transmission 24 (that is, provided between the secondary pulley 70 and the output shaft 30). The secondary pulley 70 (rotating shaft 68) and the output shaft 30 are selectively connected / disconnected. The second power transmission path PT2 is formed by engaging the second clutch C2. In the power transmission device 16, when the second power transmission path PT <b> 2 is formed, a power transmission possible state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission 24. Is done. On the other hand, the second power transmission path PT2 is set to the neutral state when the second clutch C2 is released.

  The operation of the power transmission device 16 will be described below. FIG. 2 is a diagram for explaining the switching of the travel mode using the engagement table of the engagement device for each travel pattern (travel mode) of the power transmission device 16 switched by the electronic control unit 90. In FIG. 2, C1 corresponds to the operating state of the first clutch C1, C2 corresponds to the operating state of the second clutch C2, B1 corresponds to the operating state of the first brake B1, and D1 corresponds to the meshing clutch D1. Corresponding to the operating state, “◯” indicates engagement (connection), and “×” indicates release (cutoff).

  In FIG. 2, this is a travel mode in which the power of the engine 12 is transmitted to the output shaft 30 via the gear transmission mechanism 28 (that is, a travel mode in which travel is performed using the first power transmission path PT1 via the gear transmission mechanism 28). In the gear travel mode, the first clutch C1 and the meshing clutch D1 are engaged, and the second clutch C2 and the first brake B1 are released. In this gear travel mode, forward travel is possible. In the gear travel mode in which the first brake B1 and the meshing clutch D1 are engaged and the second clutch C2 and the first clutch C1 are released, reverse travel is possible.

  Further, this is a travel mode in which the power of the engine 12 is transmitted to the output shaft 30 via the continuously variable transmission 24 (that is, a travel mode in which travel is performed using the second power transmission path PT2 via the continuously variable transmission 24). In the CVT travel mode (also referred to as a belt travel mode), the second clutch C2 is engaged and the first clutch C1 and the first brake B1 are released. In this CVT travel mode, forward travel is possible. Among the CVT traveling modes, the meshing clutch D1 is engaged in the CVT traveling (medium vehicle speed) mode, while the meshing clutch D1 is released in the CVT traveling (high vehicle speed) mode. The meshing clutch D1 is released in the CVT traveling mode (high vehicle speed) mode, for example, the dragging of the gear transmission mechanism 28 and the like during traveling in the CVT traveling mode is eliminated, and the gear transmission mechanism 28 and the planetary gear are operated at a high vehicle speed. This is to prevent the constituent member (for example, pinion gear) of the gear device 26p from rotating at a high speed. The meshing clutch D1 functions as a driven input cutoff clutch that blocks input from the drive wheel 14 side.

  The gear travel mode is selected, for example, in a low vehicle speed region including when the vehicle is stopped. In the power transmission device 16, the speed ratio γ gear (also referred to as speed ratio EL) formed in the first power transmission path PT1 via the gear transmission mechanism 28 is the second power transmission path PT2 via the continuously variable transmission 24. Is set to a value larger than the maximum gear ratio γmax that can be formed by (i.e., the gear ratio on the low side). That is, in the second power transmission path PT2, a speed ratio γcvt on the higher vehicle speed side (high side) than the speed ratio EL formed in the first power transmission path PT1 is formed. For example, the gear ratio EL corresponds to the first speed gear ratio γ1, which is the gear ratio γ of the first speed gear stage in the power transmission device 16, and the maximum gear ratio γmax of the continuously variable transmission 24 is the first gear ratio γmax in the power transmission device 16. This corresponds to the second speed gear ratio γ2 that is the speed ratio γ of the second speed gear. Therefore, the gear travel mode and the CVT travel mode are switched, for example, according to a shift line for switching between a first speed shift stage and a second speed shift stage in a shift map of a known stepped transmission. Further, in the CVT travel mode, for example, a known method is used to perform a shift in which the speed ratio γcvt is changed based on the travel state such as the accelerator opening θacc and the vehicle speed V.

  In switching from the gear travel mode to the CVT travel (high vehicle speed) mode or from the CVT travel (high vehicle speed) mode to the gear travel mode, as shown in FIG. 2, the CVT travel (medium vehicle speed) mode is passed. For example, in switching from the gear travel mode to the CVT travel (high vehicle speed) mode, a shift (for example, a clutch-to-clutch shift (hereinafter referred to as CtoC shift) that disengages the first clutch C1 and engages the second clutch C2 is performed. In this case, the shift is executed to switch to the CVT running (medium vehicle speed) mode, and then the meshing clutch D1 is released to cut off the driven input. Further, for example, in switching from the CVT travel (high vehicle speed) mode to the gear travel mode, the meshing clutch D1 is engaged as preparation for switching to the gear travel mode (that is, preparation for downshift) and the CVT travel (medium vehicle speed) mode is set. After that, a downshift is executed at a shift (for example, a CtoC shift) in which the second clutch C2 is released and the clutch is switched so as to engage the first clutch C1.

  FIG. 3 is a diagram for explaining the main functions of the control function and the control system for various controls in the vehicle 10. In FIG. 3, the vehicle 10 includes an electronic control device 90 including a control device for the power transmission device 16, for example. Therefore, FIG. 3 is a diagram showing an input / output system of the electronic control unit 90, and is a functional block diagram for explaining a main part of a control function by the electronic control unit 90. The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 90 executes output control of the engine 12, shift control of the continuously variable transmission 24, switching control of the driving mode of the power transmission device 16, and the like. The electronic control unit 90 is configured separately for engine control, hydraulic control, and the like as necessary.

  The electronic control unit 90 includes various actual values (for example, an engine) based on detection signals from various sensors (for example, various rotational speed sensors 100, 102, 104, 106, an accelerator opening sensor 108, a shift position sensor 110, and the like) included in the vehicle 10. The rotational speed Ne, the primary pulley rotational speed Npri which is the input shaft rotational speed Nin, the secondary pulley rotational speed Nsec which is the rotational speed of the rotational shaft 68, the output shaft rotational speed Nout corresponding to the vehicle speed V, the accelerator opening θacc, A shift operation position (also referred to as a shift position or a lever position) Psh corresponding to position information of the shift lever 112 as a provided shift operation member is supplied. The electronic control unit 90 also outputs an engine output control command signal Se for output control of the engine 12, a hydraulic control command signal Sccv for hydraulic control related to the shift of the continuously variable transmission 24, and a travel mode of the power transmission device 16. The hydraulic control command signal Sswt and the like for controlling the first clutch C1, the first brake B1, the second clutch C2, and the meshing clutch D1 are output. For example, as a hydraulic control command signal Sswt, for driving each solenoid valve that regulates each hydraulic pressure supplied to each hydraulic actuator of the first clutch C1, the first brake B1, the second clutch C2, and the meshing clutch D1. A command signal (hydraulic command) is output to the hydraulic control circuit 80.

  The shift lever 112 moves the driver to one of the shift operation positions Psh such as “P”, “R”, “N”, “D” in order to switch the power transmission state in the power transmission path PT of the power transmission device 16. Is manually operated selectively. “P” of the shift operation position Psh selects the parking range (P range) of the power transmission device 16, and sets both the first power transmission path PT1 and the second power transmission path PT2 to the neutral state (neutral state). The parking operation position (P operation position) for bringing the power transmission device 16 into the neutral state and mechanically preventing the output shaft 30 from rotating. Further, “R” at the shift operation position Psh selects the reverse travel range (R range) of the power transmission device 16 and is used for reverse travel in the first power transmission path PT1 by the engagement of the first brake B1 and the meshing clutch D1. This is a reverse travel operation position (R operation position) for making the power transmission device 16 in a state capable of transmitting power by forming a power transmission path and enabling reverse travel using the reverse power transmission path. Further, “N” in the shift operation position Psh is a neutral operation position (N operation position) for selecting the neutral range (N range) of the power transmission device 16 and setting the power transmission device 16 in the neutral state. Further, “D” of the shift operation position Psh selects the forward travel range (D range) of the power transmission device 16, and is used for the forward movement in the first power transmission path PT1 by the engagement of the first clutch C1 and the meshing clutch D1. A power transmission path is formed by forming the power transmission path or by forming the second power transmission path PT2 by engaging the second clutch C2, and the power transmission device 16 is set in a state capable of transmitting power, and the forward traveling power transmission path is used. This is a forward travel operation position (D operation position) for enabling travel. “P” and “N” of the shift operation position Psh are respectively non-traveling ranges of the power transmission device 16 in which power transmission in the power transmission path PT is interrupted (that is, the power transmission device 16 that disables traveling of the vehicle 10). This is a non-traveling operation position for selecting (non-traveling range). “R” and “D” of the shift operation position Psh are respectively the travel range of the power transmission device 16 that can transmit power in the power transmission path PT (that is, the travel range of the power transmission device 16 that enables the vehicle 10 to travel). This is the travel operation position for selecting).

  FIG. 4 illustrates a portion of the hydraulic control circuit 80 provided in the power transmission device 16 that controls the hydraulic pressure related to the continuously variable transmission 24, the first clutch C1, the second clutch C2, and the meshing clutch D1. FIG. The hydraulic control circuit 80 supplies a primary solenoid valve SLP for controlling the primary pressure Pin supplied to the primary pulley 66, a secondary solenoid valve SLS for controlling the secondary pressure Pout supplied to the secondary pulley 70, and the first clutch C1. C1 solenoid valve SL1 for controlling the C1 pressure Pc1 as the clutch hydraulic pressure, C2 solenoid valve SL2 for controlling the C2 pressure Pc2 as the clutch hydraulic pressure supplied to the second clutch C2, and the hydraulic pressure for operating the synchromesh mechanism S1 A synchro electromagnetic valve SLG for controlling the synchro control pressure Ps1 supplied to the actuator 62, a primary pressure control valve 82, and a secondary pressure control valve 84 are provided. In the hydraulic control circuit 80, the line pressure PL is regulated by a regulator valve (not shown) based on the hydraulic pressure discharged from the oil pump 42.

  Each of the solenoid valves SLP, SLS, SL1, SL2, and SLG is a linear solenoid valve that is driven by a hydraulic control command signal (drive current) as an instruction value output from the electronic control unit 90. The primary pressure control valve 82 is operated based on the SLP pressure Pslp as the pilot pressure output from the primary solenoid valve SLP, thereby adjusting the primary pressure Pin using the line pressure PL as a source pressure. The secondary pressure control valve 84 is operated based on the SLS pressure Psls as the pilot pressure output from the secondary solenoid valve SLS, thereby adjusting the secondary pressure Pout using the line pressure PL as a source pressure. The SL1 pressure Psl1 output from the C1 electromagnetic valve SL1 is supplied to the first clutch C1 as the C1 pressure Pc1. The SL2 pressure Psl2 output from the C2 solenoid valve SL2 is supplied to the second clutch C2 as the C2 pressure Pc2. The SLG pressure Pslg output from the synchronizing solenoid valve SLG is supplied to the hydraulic actuator 62 as the synchronizing control pressure Ps1.

  The electronic control unit 90 includes engine output control means, that is, an engine output control unit 92, and hydraulic control means, that is, a hydraulic control unit 94.

  The engine output control unit 92 is requested, for example, by applying the accelerator opening θacc and the vehicle speed V to a relationship (for example, a driving force map) that has been obtained and stored experimentally or design in advance (that is, predetermined). A driving force Fdem is calculated, a target engine torque Tetgt from which the required driving force Fdem is obtained is set, and an engine output control command signal Se for controlling the output of the engine 12 so as to obtain the target engine torque Tetgt is set to a throttle actuator, Output to a fuel injection device or ignition device.

  The hydraulic control unit 94 outputs a command to the hydraulic control circuit 80 to engage the engagement clutch D1 by the hydraulic actuator 62 in preparation for the gear traveling mode while the vehicle is stopped. Thereafter, when the shift lever 112 is switched to the D operation position (or the R operation position), the hydraulic control unit 94 outputs a command to engage the first clutch C1 (or the first brake B1) to the hydraulic control circuit 80. To do.

  Further, in the CVT travel mode, the hydraulic control unit 94 applies the accelerator opening θacc and the vehicle speed V to, for example, a predetermined relationship (for example, the CVT shift map and the belt clamping pressure map), so that the continuously variable transmission 24 Primary pressure Pin and secondary pressure Pout for achieving the target gear ratio γtgt of the continuously variable transmission 24 where the operating point of the engine 12 is on a predetermined optimum line (for example, engine optimum fuel consumption line) while preventing belt slippage. Each hydraulic pressure command (hydraulic pressure control command signal Sccv) is determined, and each hydraulic pressure command is output to the hydraulic pressure control circuit 80 to execute CVT shift.

  Further, the hydraulic control unit 94 executes switching control for switching between the gear travel mode and the CVT travel mode. Specifically, the hydraulic control unit 94, for example, applies the vehicle speed V and the downshift line with a predetermined hysteresis for switching between the gear ratio EL in the gear travel mode and the maximum gear ratio γmax in the CVT travel mode. Switching the speed ratio γ is determined by applying the accelerator opening θacc, and the traveling mode is switched based on the determination result.

  When the hydraulic control unit 94 determines an upshift during traveling in the gear traveling mode and switches to the CVT traveling (medium vehicle speed) mode, the hydraulic control unit 94 performs the CtoC shift in which the first clutch C1 is released and the second clutch C2 is engaged. A command to be executed is output to the hydraulic control circuit 80. Thereby, the power transmission path PT in the power transmission device 16 is switched from the first power transmission path PT1 to the second power transmission path PT2. When the hydraulic control unit 94 switches from the CVT travel (medium vehicle speed) mode to the CVT travel (high vehicle speed) mode, the hydraulic control unit 94 outputs a command to the hydraulic control circuit 80 to release the meshing clutch D1 by the hydraulic actuator 62. Further, when switching from the CVT travel (high vehicle speed) mode to the CVT travel (medium vehicle speed) mode, the hydraulic control unit 94 outputs a command for performing the engagement operation of the meshing clutch D1 by the hydraulic actuator 62 to the hydraulic control circuit 80. . When the hydraulic pressure control unit 94 determines a downshift during traveling in the CVT traveling (medium vehicle speed) mode and switches to the gear traveling mode, the hydraulic control unit 94 releases the second clutch C2 and engages the first clutch C1. A command to be executed is output to the hydraulic control circuit 80. As a result, the power transmission path PT in the power transmission device 16 is switched from the second power transmission path PT2 to the first power transmission path PT1. In the switching control for switching between the gear travel mode and the CVT travel mode, the first power transmission path PT1 and the second power transmission are simply performed by passing the torque by the CtoC shift through the state of the CVT travel (medium vehicle speed) mode. Since the path PT2 is switched, the switching shock is suppressed.

  Here, in consideration of preventing belt slippage, it is desirable to guarantee the necessary minimum pressure Pinlim of the primary pressure Pin. Parts (for example, the primary solenoid valve SLP and the primary pressure control valve 82) in the hydraulic control circuit 80 that supplies the primary pressure Pin have individual variations. Therefore, as shown in FIG. 7, the characteristic of the actual value with respect to the hydraulic pressure control command signal Sccv (that is, the drive current of the electromagnetic valve SLP) (or the pilot pressure SLP pressure Pslp) of the primary pressure Pin also varies. In order to guarantee the necessary minimum pressure Pinlim against variations in the actual value of the primary pressure Pin, it is necessary to set the designed primary pressure Pin to the high pressure side as shown by the solid line in FIG. Considering that the target gear ratio γtgt is realized by the mutual relationship between the primary thrust Win and the secondary thrust Wout, the secondary pressure Pout must also be set high, and the transmission efficiency of the continuously variable transmission 24 can be reduced. There is sex. The necessary minimum pressure Pinlim is, for example, a lower limit value of a predetermined primary pressure Pin for preventing belt slip.

  Therefore, as shown in FIG. 4, the power transmission device 16 includes a hydraulic switch 88 that switches the operating state to the oil passage 86 that supplies the primary pressure Pin to the primary pulley 66 at the necessary minimum pressure Pinlim of the primary pulley 66. .

  FIG. 5 is a diagram illustrating an example of the operating state of the hydraulic switch 88 and the characteristics of the primary pressure Pin. As shown in FIG. 5, the hydraulic switch 88 is turned off when the primary pressure Pin is less than the necessary minimum pressure Pinlim, and is turned on when the primary pressure Pin is equal to or higher than the necessary minimum pressure Pinlim. An on / off signal Son from the hydraulic switch 88 is input to the electronic control unit 90 (see FIGS. 3 and 4). When the primary pressure Pin reaches the required minimum pressure Pinlim when the primary pressure Pin is raised from a value less than the required minimum pressure Pinlim, the operating state of the hydraulic switch 88 is switched from OFF to ON. Accordingly, when the hydraulic switch 88 is switched from OFF to ON (or from ON to OFF), the primary pressure Pin is an instruction value for the primary pressure Pin, that is, the primary pressure Pin (ie, the drive current of the solenoid valve SLP) The pressure Pin is set to the necessary minimum pressure Pinlim. The hydraulic control command signal Scvt at this time is set as a minimum pressure guarantee current A that is an instruction value corresponding to the necessary minimum pressure Pinlim, and a hydraulic control command for controlling the primary pressure Pin with reference to the minimum pressure guarantee current A The signal Sccv is output to the hydraulic control circuit 80 (particularly, the solenoid valve SLP). This means that the required minimum pressure Pinlim can be guaranteed with the minimum pressure guarantee current A. As a result, it is not necessary to design the characteristics of the primary pressure Pin in anticipation of variations among the individual hydraulic control circuits 80.

  In order to set the minimum pressure guarantee current A, it is necessary to detect a change in the operating state of the hydraulic switch 88 by changing (for example, gradually increasing or gradually decreasing) the hydraulic control command signal Sccv of the primary pressure Pin. For this reason, a control (for example, “Pin required minimum pressure determination logic”) that sets the minimum pressure guarantee current A when the vehicle state does not affect the vehicle running even if the hydraulic pressure control command signal Sccv of the primary pressure Pin is changed. It is desirable to execute. As such a vehicle state, for example, a state in which the power transmission device 16 is set to a non-traveling range (P range or N range) while the engine 12 is being driven and the continuously variable transmission 24 is freely rotating, or This is a vehicle state in which the continuously variable transmission 24 is freely rotating, assuming that the vehicle is traveling in the gear travel mode. During traveling in the gear travel mode, it is better not to immediately determine the switch to the CVT travel mode. Therefore, the vehicle speed V is somewhat lower than the vehicle speed at which the switch from the gear travel mode to the CVT travel mode is determined. The following is desirable.

  In order to execute the Pin necessary minimum pressure determination logic, the electronic control unit 90 further includes vehicle state determination means, that is, a vehicle state determination unit 96, and necessary minimum pressure determination means, that is, a necessary minimum pressure determination unit 98.

  The vehicle state determination unit 96 determines whether or not the power transmission device 16 is in a vehicle state in the non-traveling range (P range or N range) while the engine 12 is being driven. The vehicle state determination unit 96 determines whether or not the power transmission device 16 is in the non-traveling range based on whether or not the shift operation position Psh of the shift lever 112 is the non-traveling operation position (P operation position or N operation position). Determine. The vehicle state determination unit 96 determines whether or not the vehicle is traveling in the gear travel mode. More preferably, the vehicle state determination unit 96 determines whether the vehicle is traveling in the gear travel mode and whether the vehicle speed V is equal to or lower than a predetermined vehicle speed.

  The necessary minimum pressure determination unit 98 is determined when the vehicle state determination unit 96 determines that the power transmission device 16 is in a vehicle state in which the engine 12 is in the non-traveling range while the engine 12 is being driven. If it is determined that the vehicle is traveling in the travel mode, the Pin required minimum pressure determination logic is executed. Specifically, the necessary minimum pressure determination unit 98 changes the hydraulic control command signal Sccv of the primary pressure Pin so that the primary pressure Pin varies (for example, gradually increases or decreases) in a predetermined low pressure region, and the hydraulic switch 88 The switching of the operating state is detected (that is, the switching of the on / off signal Son from the hydraulic switch 88 is detected). The necessary minimum pressure determination unit 98 stores the hydraulic pressure control command signal Scvt of the primary pressure Pin when the switching of the operating state of the hydraulic switch 88 is detected, and sets it as the minimum pressure guarantee current A. With the above series of operations, the necessary minimum pressure determination unit 98 executes the Pin necessary minimum pressure determination logic. Thereby, the minimum pressure guarantee current A is determined for each vehicle 10 (that is, for each unit). The predetermined low-pressure region is a region that is determined in advance in consideration of variations as a region of the primary pressure Pin including the necessary minimum pressure Pinlim, for example.

  The hydraulic pressure control unit 94 generates a hydraulic pressure control command signal Sccv for controlling the primary pressure Pin based on the minimum pressure guarantee current A set by the necessary minimum pressure determination unit 98 as a reference. Output to.

  FIG. 6 is a flowchart for explaining the main part of the control operation of the electronic control unit 90, that is, the control operation for improving the transmission efficiency of the continuously variable transmission 24. The flowchart of FIG. 6 may be repeatedly executed, for example, but is executed once during one trip from ignition on to ignition off, or is executed after the engine 12 has been warmed up even during the one trip, or It may be executed once every predetermined period of several days or weeks.

  In FIG. 6, first, in step S <b> 10 (hereinafter, step is omitted) corresponding to the function of the vehicle state determination unit 96, the power transmission device 16 is in the non-traveling range (P range or N range) while the engine 12 is being driven. It is determined whether or not the vehicle state has been set. If the determination in S10 is negative, it is determined in S20 corresponding to the function of the vehicle state determination unit 96 whether the vehicle is traveling in the gear travel mode. If the determination at S20 is negative, this routine is terminated. When the determination at S10 is affirmed or when the determination at S20 is affirmed, the Pin necessary minimum pressure determination logic is executed at S30 corresponding to the function of the necessary minimum pressure determination unit 98.

  As described above, according to the present embodiment, the oil passage 86 that supplies the primary pressure Pin to the primary pulley 66 is provided with the hydraulic switch 88 that can switch the operating state at the minimum required pressure Pinlim of the primary pulley 66. When the hydraulic pressure control command signal Sccv (that is, the drive current of the solenoid valve SLP) of the primary pressure Pin is changed so as to change the primary pressure Pin in a predetermined low pressure region, the change of the operating state of the hydraulic switch 88 is detected. Since the hydraulic control command signal Sccvt is set as the minimum pressure guarantee current A that is an instruction value corresponding to the necessary minimum pressure Pinlim, the primary pressure Pin can be controlled with the minimum pressure guarantee current A as a reference. Thereby, it is not necessary to set the design primary pressure Pin on the high pressure side in consideration of individual variations of components in the hydraulic control circuit 80. That is, the necessary minimum pressure Pinlim of the primary pulley 66 can be guaranteed without setting the designed primary pressure Pin on the high pressure side. Therefore, the transmission efficiency of the continuously variable transmission 24 can be improved.

  In addition, since it is not necessary to set the required minimum pressure Pinlim of the primary pulley 66 in consideration of individual variations of components in the hydraulic control circuit 80, the accuracy of the components can be reduced, leading to cost reduction. Further, since the necessary minimum pressure Pinlim can be set for each individual, the optimum speed change performance can always be established, leading to improvement in drivability. By executing the Pin required minimum pressure determination logic, a command value (minimum pressure guarantee current A) corresponding to the required minimum pressure Pinlim is appropriately set, and the primary pressure Pin can be appropriately controlled.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the hydraulic switch 88 is turned off when the primary pressure Pin is less than the necessary minimum pressure Pinlim, and turned on when the primary pressure Pin is higher than the necessary minimum pressure Pinlim, but the hydraulic switch 88 is turned on and off. Or vice versa. In short, any hydraulic switch 88 may be used as long as the operating state is switched at the necessary minimum pressure Pinlim. Further, as shown in FIG. 4, the hydraulic switch 88 is provided in the hydraulic control circuit 80, but may be provided outside the hydraulic control circuit 80.

  In the above-described embodiment, the gear transmission mechanism 28 is a transmission mechanism in which one gear stage having a lower gear ratio than the maximum gear ratio γmax of the continuously variable transmission 24 is formed. Not exclusively. For example, the gear transmission mechanism 28 may be a transmission mechanism in which a plurality of gear stages having different gear ratios are formed. That is, the gear transmission mechanism 28 may be a stepped transmission that is shifted to two or more stages. Further, the gear transmission mechanism 28 may be a transmission mechanism that forms a gear ratio higher than the minimum gear ratio γmin of the continuously variable transmission 24 and a gear ratio lower than the maximum gear ratio γmax. Further, the gear transmission mechanism 28 may be a transmission mechanism that forms only a gear ratio higher than the minimum gear ratio γmin of the continuously variable transmission 24.

  In the above-described embodiment, the traveling mode of the power transmission device 16 is switched using a predetermined shift map, but the present invention is not limited to this. For example, the driving request amount (for example, required torque) of the driver is calculated on the basis of the vehicle speed V and the accelerator opening degree θacc, and the speed change ratio that can satisfy the required torque is set, so that the driving mode of the power transmission device 16 is set. May be switched.

  In the above-described embodiment, the power transmission device 16 includes the first power transmission path PT1 via the gear transmission mechanism 28 and the second power transmission path PT2 via the continuously variable transmission 24, and the input shaft 22. Although it provided in parallel with the output shaft 30, it is not restricted to this. The present invention can be applied to any power transmission device including a continuously variable transmission that transmits the power of the driving force source to the driving wheel side via the continuously variable transmission 24. In the case where the first power transmission path PT1 via the gear transmission mechanism 28 is not provided, the above-described Pin required minimum pressure determination logic is such that the power transmission device 16 operates in the non-traveling range (P range or N range) while the engine 12 is being driven. This is executed when the vehicle state is set to (range). Therefore, S20 in FIG. 6 is not provided.

  In the above-described embodiment, the engine 12 is exemplified as the driving force source. However, the present invention is not limited to this. For example, the driving force source may employ another prime mover such as an electric motor alone or in combination with the engine 12. Further, the power of the engine 12 is transmitted to the input shaft 22 via the torque converter 20, but the present invention is not limited to this. For example, instead of the torque converter 20, another fluid transmission device such as a fluid coupling (fluid coupling) having no torque amplification action may be used. Alternatively, this fluid transmission device is not necessarily provided. Further, the meshing clutch D1 is provided with the synchromesh mechanism S1, but the synchromesh mechanism S1 is not necessarily provided. Moreover, although the transmission belt 72 was illustrated as a transmission element of the continuously variable transmission 24, it is not restricted to this. For example, the transmission element may be a transmission chain. In this case, the continuously variable transmission is a chain-type continuously variable transmission, but in a broad sense, the concept of a belt-type continuously variable transmission may include a chain-type continuously variable transmission.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

12: Engine (power source)
14: Drive wheel 16: Vehicle power transmission device 24: Continuously variable transmission 66: Primary pulley 70: Secondary pulley 72: Transmission belt (transmission element)
80: Hydraulic control circuit 86: Oil passage 88: Hydraulic switch 90: Electronic control device (control device)
98: Required minimum pressure determination unit

Claims (1)

A continuously variable transmission having a primary pulley, a secondary pulley, and a transmission element wound around each of the pulleys, and transmitting the power of the driving force source to the driving wheel side, and a hydraulic pressure for supplying each pulley hydraulic pressure to each of the pulleys A control device for a vehicle power transmission device comprising a control circuit,
The vehicle power transmission device is switched to an oil passage for supplying primary pulley hydraulic pressure to the primary pulley at a predetermined minimum necessary pressure of the primary pulley for preventing slippage of the transmission element. Equipped with a hydraulic switch,
The instruction value of the primary pulley oil pressure is changed so as to vary the primary pulley oil pressure in a predetermined low pressure region, and the instruction value when the change of the operation state of the oil pressure switch is detected corresponds to the necessary minimum pressure. A control device for a vehicular power transmission device, comprising a minimum required pressure determination unit set as an instruction value.

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