Vehicle power transmission device control device

Abstract

To provide a device for controlling a vehicular power transmission device that accurately detects an off failure of an on-off solenoid and properly transitions to a fail-safe mode.SOLUTION: When detecting an electric failure of an on-off solenoid valve SC3, a device for controlling a vehicular power transmission device accurately detects an off failure of the on-off solenoid valve SC3 on the basis of an engagement state of a backing brake B1 when the transmission is shifted to an R range. When detecting an off failure of the on-off solenoid valve SC3, the device for controlling a vehicular power transmission device shifts the mode to a fail-safe mode in which the vehicle travels in a state where a lock-up clutch LU is released and which enables the vehicle to execute evacuation travel. Since the lock-up clutch LU is released during the evacuation travel, the lock-up clutch LU is protected and evacuation travel performance is improved.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle power transmission device equipped with an on / off solenoid valve for switching the supply destination of control oil pressure output from a specified solenoid valve to either a lock-up clutch circuit of a lock-up clutch or a specified engagement device. [Background technology]

[0002] Patent Document 1 discloses a vehicle power transmission device that can be switched between multiple driving modes by switching the operating states of multiple solenoid valves. The vehicle power transmission device in Patent Document 1 is such a device. The vehicle power transmission device in Patent Document 1 is configured with multiple solenoid valves SLP, SLS, SL1, SL2, SLU, and SLG, and is configured to be switchable between multiple driving modes such as a gear driving mode and a CVT driving mode (belt driving mode) by switching the operating states of these multiple solenoid valves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-56868 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the solenoid valves for controlling the operating states of the multiple engagement devices provided in the vehicle power transmission device are provided independently of each other, which causes a problem of high parts costs. In response to this, it is conceivable to configure a single on-off solenoid to switch the supply destination of the control oil pressure output from a specific solenoid valve to either a lockup clutch circuit that controls a lockup clutch or a specific engagement device, in order to reduce the number of parts. Here, in the case where the control oil pressure of the specific solenoid valve is supplied to the lockup clutch circuit of the lockup clutch when the on-off solenoid valve is in the off state (non-operated state), and the control oil pressure is supplied to the specific engagement device when the on-off solenoid valve is in the on state (operated state), if an off failure occurs in which the on-off solenoid valve is fixed in the off state, the lockup clutch will be engaged and will no longer be protected.

[0005] Therefore, when an off failure of the on-off solenoid valve occurs, it is considered that the vehicle will transition to a fail-safe mode in which the lock-up clutch is released. However, if only an electrical abnormality of the on-off solenoid valve is detected, the on-off solenoid valve may be mechanically in the on-state (operated state). In this case, even if the vehicle transitions to the fail-safe mode due to the off failure of the on-off solenoid valve, there is a risk that the vehicle will not be able to continue traveling (evacuation traveling) because the on-off solenoid valve is in the on-state. In addition, while traveling with the lock-up clutch engaged, the on-off solenoid valve is in the off-state. Therefore, even if the on-off solenoid valve has an off failure, there is no change in the traveling behavior, so it is difficult to detect the off failure of the on-off solenoid valve. Therefore, if the off failure of the on-off solenoid valve is not accurately detected, the vehicle will not be able to transition to the fail-safe mode appropriately, and there is a risk that the evacuation traveling performance will be limited.

[0006] The present invention has been made against the background of the above circumstances, and its object is to provide a control device for a vehicle power transmission device that can accurately detect an off failure of an on-off solenoid and appropriately transition to a fail-safe mode. [Means for solving the problem]

[0007] The gist of a first invention is (a) a control device for a vehicle power transmission device that is applied to a vehicle power transmission device in which a plurality of driving modes are switched by switching the operating states of a plurality of solenoid valves, and has an on-off solenoid valve for switching the supply destination of a control oil pressure output from a predetermined solenoid valve to either a lock-up clutch circuit that controls a lock-up clutch or a predetermined engagement device, (b) the on-off solenoid valve is configured so that the control oil pressure is supplied to the lock-up clutch circuit in a non-operated state, and the control oil pressure is supplied to the predetermined engagement device in an operated state, and (c) the on-off solenoid valve is non-operated when the lock-up clutch is engaged. (d) the on-off solenoid valve is switched to an active state when driving in a predetermined driving range, and (e) when an electrical failure of the on-off solenoid valve is detected, a determination is made as to whether or not an off failure has occurred in which the on-off solenoid valve is in a non-operated state based on the engagement state of the predetermined engagement device when the vehicle is switched to the predetermined driving range, and when an off failure of the on-off solenoid valve is detected, a transition is made to a fail-safe mode in which the vehicle is driven with the lock-up clutch released even when the on-off solenoid valve is in a non-operated state. Effect of the Invention

[0008] According to the first invention, when an electrical failure of the on-off solenoid valve is detected, an off failure of the on-off solenoid valve is accurately detected based on the engagement state of a predetermined engagement device when switched to a predetermined range. Also, when an off failure of the on-off solenoid valve is detected, a transition is made to a fail-safe mode in which the vehicle runs with the lock-up clutch released, making it possible to run in an evacuation mode. Also, since the lock-up clutch is released during evacuation running, the lock-up clutch is protected and evacuation running performance is improved.

[0009] Preferably, the lock-up clutch circuit is configured such that, when the driving mode is shifted to the fail-safe mode, the lock-up clutch is switched to the release side by the control oil pressure output from a specified solenoid valve. In this way, when an OFF failure of the on-off solenoid valve is detected, the mode is shifted to the fail-safe mode, and the control oil pressure of the specified solenoid valve is supplied to the lock-up clutch circuit, thereby releasing the lock-up clutch. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a schematic configuration of a vehicle power transmission device according to an embodiment of the present invention; [Diagram 2] 2 is a hydraulic circuit diagram illustrating a main part of a hydraulic control circuit provided in the vehicle power transmission device of FIG. 1. [Diagram 3] 2 is a diagram illustrating the relationship between a plurality of power transmission ranges and a plurality of driving modes selectable in the D range provided in the vehicle power transmission device of FIG. 1, and the operating states of a plurality of solenoid valves. [Figure 4] 2 is a flowchart illustrating a control function of the electronic control device of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0012] 1 is a schematic diagram for explaining the general configuration of a vehicle power transmission device 10 according to an embodiment of the present invention, in which a plurality of parallel shafts are shown developed so as to be positioned on one plane. The vehicle power transmission device 10 is a horizontally mounted type suitable for use in FF (front engine, front drive) vehicles, in which power from an engine 12, which is a driving force source for traveling, is transmitted from a torque converter 14, which serves as a fluid-type transmission device, to an automatic transmission 16, to a differential gear device 18, and then distributed to left and right driving wheels 20L, 20R.

[0013] The torque converter 14 includes a pump wheel 14p connected to the crankshaft of the engine 12 and a turbine wheel 14t connected to the input shaft 22 of the automatic transmission 16, and transmits power via a fluid (hydraulic oil), with the pump wheel 14p and the turbine wheel 14t directly connected via a lock-up clutch LU. A mechanical oil pump 74 is connected to the pump wheel 14p, and is driven to rotate by the engine 12 to output hydraulic pressure, thereby serving as a hydraulic pressure source for a hydraulic control circuit 70 shown by a dashed line in Fig. 1. The connection destination, i.e., the installation position, of the oil pump 74 can be changed as appropriate, and an electric oil pump can also be used.

[0014] Fig. 2 specifically illustrates a main portion of the hydraulic control circuit 70, i.e., a hydraulic operation control unit 72 constituted by a valve body, etc. The pressure difference ΔPlu of the lock-up clutch LU shown in Fig. 2 corresponds to the pressure difference (=Pon-Poff) between the hydraulic pressure Pon in the engagement-side oil chamber of the lock-up clutch LU and the hydraulic pressure Poff in the release-side oil chamber of the lock-up clutch LU. When the pressure difference ΔPlu is zero, the lock-up clutch LU is released, and when the pressure difference ΔPlu is a positive value greater than zero, the lock-up clutch LU is slip-engaged or fully engaged.

[0015] The differential pressure ΔPlu is regulated and controlled by a lockup control valve 108 (hereinafter, control valve 108). The secondary pressure Psec regulated by the pressure regulating valve 106 is supplied as an original pressure to the control valve 108, and the hydraulic pressure Pon in the engagement side oil chamber and the hydraulic pressure Poff in the release side oil chamber of the lockup clutch LU are controlled by the control hydraulic pressure Pslu supplied from the linear solenoid valve SLU via the SC3 switching valve 114. That is, the differential pressure ΔPlu of the lockup clutch LU is controlled by the control hydraulic pressure Pslu of the linear solenoid valve SLU. The linear solenoid valve SLU is electrically controlled by the electronic control device 80 to regulate the control hydraulic pressure Pslu.

[0016] The automatic transmission 16 includes an input shaft 22 provided integrally with a turbine shaft which is an output rotating member of the torque converter 14, a belt-type continuously variable transmission 24 connected to the input shaft 22, a forward / reverse switching device 26 and a gear transmission mechanism (gear-type power transmission device) 28 which are also connected to the input shaft 22 and provided in parallel with the belt-type continuously variable transmission 24, an output shaft 30 which is a common output rotating member of the belt-type continuously variable transmission 24 and the gear transmission mechanism 28, and a reduction gear device 32. A small-diameter gear 34 of the reduction gear device 32 is meshed with a ring gear 36 of the differential gear device 18. In the automatic transmission 16 thus configured, power from the engine 12 is transmitted from the torque converter 14 to the output shaft 30 via the belt-type continuously variable transmission 24. Alternatively, the power from the engine 12 is transmitted to the output shaft 30 via the forward / reverse switching device 26 and the gear transmission mechanism 28 without passing through the belt-type continuously variable transmission 24. The power transmitted to the output shaft 30 is then transmitted to the left and right drive wheels 20L, 20R via the reduction gear device 32 and the differential gear device 18.

[0017] In this way, the automatic transmission 16 has a first power transmission path TP1 that transmits power via the forward / reverse switching device 26 and the gear shift mechanism 28, and a second power transmission path TP2 that transmits power via the belt-type continuously variable transmission 24, which are provided in parallel as power transmission paths that transmit power from the engine 12 from the input shaft 22 to the output shaft 30. In the automatic transmission 16, the power transmission path is switched between the first power transmission path TP1 and the second power transmission path TP2 depending on the running state of the vehicle. For this reason, the automatic transmission 16 includes a forward clutch C1 and a reverse brake B1 that connect and disconnect (connect and disconnect) the power transmission in the first power transmission path TP1, and a belt running clutch C2 that connects and disconnects the power transmission in the second power transmission path TP2.

[0018] The forward clutch C1 is a clutch that is engaged when the power from the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the first power transmission path TP1. The reverse brake B1 is a brake that is engaged when the power from the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the first power transmission path TP1. The belt running clutch C2 is a clutch that is engaged when the power from the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the second power transmission path TP2. In addition, the first power transmission path TP1 is provided with a synchromesh clutch S1 in series with the forward / reverse switching device 26 and the gear shift mechanism 28, specifically downstream of them. The forward clutch C1 and the synchromesh clutch S1 are engaged to enable forward travel via the first power transmission path TP1. Alternatively, the reverse brake B1 and the synchromesh clutch S1 are engaged to enable reverse travel via the first power transmission path TP1. Furthermore, the belt running clutch C2 is engaged, thereby enabling forward running via the second power transmission path TP2.

[0019] The forward / reverse switching device 26 is mainly composed of a double-pinion type planetary gear device, in which the carrier 26c is integrally connected to the input shaft 22, and the sun gear 26s is connected to a small-diameter gear 42 arranged coaxially and rotatably relative to the input shaft 22, while the ring gear 26r is selectively stopped from rotating via a reverse brake B1, and the carrier 26c and the sun gear 26s are selectively connected via a forward clutch C1. When the forward clutch C1 is engaged and the reverse brake B1 is released, the input shaft 22 is directly connected to the small-diameter gear 42, and a forward power transmission state is established. On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the small-diameter gear 42 is rotated in the opposite direction relative to the input shaft 22, and a reverse power transmission state is established. When both the forward clutch C1 and the reverse brake B1 are released, the vehicle enters a neutral state in which power transmission through the first power transmission path TP1 is interrupted.

[0020] The forward clutch C1 and the reverse brake B1 are both hydraulic friction engagement devices of a multiple plate type in which a plurality of friction materials are frictionally engaged by a hydraulic cylinder, and the C1 engagement oil pressure Pc1 and the B1 engagement oil pressure Pb1 supplied to the hydraulic cylinders are regulated and controlled by linear solenoid valves (solenoid valves) SL1 and SLU provided in the hydraulic operation control section 72, respectively, to continuously adjust their engagement forces, i.e., transmission torque capacities. The linear solenoid valves SL1 and SLU are electrically controlled by the electronic control device 80, respectively, to regulate the C1 engagement oil pressure Pc1 and the B1 engagement oil pressure Pb1.

[0021] The gear transmission mechanism 28 includes a small diameter gear 42, a large diameter gear 46 that is non-rotatably mounted on a countershaft 44 and meshes with the small diameter gear 42, and a small diameter idler gear 48 that is coaxially mounted so as to be rotatable relative to the countershaft 44. A synchromesh clutch S1 is provided between the countershaft 44 and the idler gear 48 to connect and disconnect power transmission therebetween.

[0022] The synchronous mesh clutch S1 is equipped with a synchromesh mechanism (synchronization mechanism) consisting of a synchronizer ring, etc., and when the clutch hub sleeve 50 is moved in the connecting direction, which is the left direction in Figure 1, by a hydraulic cylinder not shown, the idler gear 48 is caused to rotate synchronously with the counter shaft 44 via the synchronizer ring, and when the clutch hub sleeve 50 is moved further, the idler gear 48 is connected to the counter shaft 44 via spline teeth provided on the inner surface of the clutch hub sleeve 50 so that it cannot rotate relative to the counter shaft 44.

[0023] The hydraulic cylinder of the synchronous mesh clutch S1 is supplied with an S1 engagement hydraulic pressure Ps1 adjusted and controlled by a linear solenoid valve SL1 provided in the hydraulic actuation control section 72, and the synchronous mesh clutch S1 is engaged in synchronous mesh based on the S1 engagement hydraulic pressure Ps1. Alternatively, the hydraulic cylinder of the synchronous mesh clutch S1 is supplied with the line pressure PL as the S1 engagement hydraulic pressure Ps1 as it is, and the synchronous mesh clutch S1 is maintained in an engaged state at this time. The line pressure PL is adjusted in response to, for example, the accelerator operation amount, i.e., the accelerator opening θacc, which is the required output amount, and the throttle valve opening θth, which corresponds to the engine torque, and the like. The linear solenoid valve SL1 is electrically controlled by the electronic control device 80 to adjust the S1 engagement hydraulic pressure Ps1.

[0024] The idler gear 48 is meshed with a large diameter gear 58 provided on the output shaft 30, and when either the forward clutch C1 or the reverse brake B1 is engaged and the synchromesh clutch S1 is connected, the power from the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the forward / reverse switching device 26, the gear transmission mechanism 28, the idler gear 48, and the large diameter gear 58 in this order. At this time, a first power transmission path TP1 is established. Note that speed change (reduction) also occurs between the small diameter idler gear 48 and the large diameter gear 58, and it can be considered that the gear transmission mechanism 28 is configured including these.

[0025] The belt-type continuously variable transmission 24 includes a primary pulley 60 with a variable effective diameter provided on the input shaft 22, a secondary pulley 64 with a variable effective diameter provided on a rotating shaft 62 coaxial with the output shaft 30, and a transmission belt (belt) 66 wound around the pair of variable pulleys 60, 64, and power is transmitted through friction between the pair of variable pulleys 60, 64 and the transmission belt 66. The pair of variable pulleys 60, 64 each include a hydraulic cylinder 60c, 64c as a hydraulic actuator that applies a thrust to change the V-groove width. For example, the primary pulley hydraulic pressure Pslp supplied to the hydraulic cylinder 60c is controlled by a linear solenoid valve (solenoid valve) SLP provided in the hydraulic operation control unit 72, whereby the V-groove width of both variable pulleys 60, 64 is changed, changing the wrapping diameter (effective diameter) of the transmission belt 66, and the gear ratio γ2 is continuously changed. Furthermore, the secondary pulley hydraulic pressure Psls supplied to the hydraulic cylinder 64c is regulated and controlled by a linear solenoid valve (solenoid valve) SLS provided in the hydraulic operation control section 72, thereby adjusting the belt clamping pressure so as not to cause slippage of the transmission belt 66. The linear solenoid valves SLP, SLS are electrically controlled by an electronic control device 80 to regulate the primary pulley hydraulic pressure Pslp and the secondary pulley hydraulic pressure Psls, respectively.

[0026] The output shaft 30 is disposed coaxially with the rotating shaft 62 so as to be rotatable relative to the rotating shaft 62, and a belt running clutch C2 provided between the output shaft 30 and the secondary pulley 64 connects and disconnects power transmission between the output shaft 30 and the secondary pulley 64. When the belt running clutch C2 is engaged, power from the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the belt-type continuously variable transmission 24, and a second power transmission path TP2 is established.

[0027] The belt driving clutch C2 is a multi-plate type friction engagement device in which multiple friction materials are frictionally engaged by a hydraulic cylinder. The C2 engagement hydraulic pressure Pc2 supplied to the hydraulic cylinder is regulated and controlled by a linear solenoid valve (solenoid valve) SL2 provided in the hydraulic operation control section 72, thereby continuously adjusting the engagement force, i.e., the transmission torque capacity. The linear solenoid valve SL2 regulates the C2 engagement hydraulic pressure Pc2 by being electrically controlled by the electronic control device 80. In other words, the linear solenoid valve SL2 is a solenoid valve that supplies hydraulic pressure to the belt driving clutch C2.

[0028] In such a power transmission device 10 for a vehicle, the speed ratio γ1 of the first power transmission path TP1, which is determined by the gear ratio of the gear shift mechanism 28, etc., is set to be larger than the maximum value γ2max of the speed ratio γ2 of the second power transmission path TP2. Therefore, when the vehicle starts or runs under high load, the vehicle runs in a gear running mode using the first power transmission path TP1. In addition, with an increase in the vehicle speed V or a decrease in the required driving force, the vehicle is switched to a belt running mode using the second power transmission path TP2. The mode switching from the gear running mode to the belt running mode (effectively an upshift of the automatic transmission 16) is performed by a clutch-to-clutch shift (CtoC) in which the forward clutch C1 is released and the belt running clutch C2 is engaged. In addition, the mode switching from the belt running mode to the gear running mode (effectively a downshift of the automatic transmission 16) is performed by a clutch-to-clutch shift in which the belt running clutch C2 is released and the forward clutch C1 is engaged. The speed change ratios γ1 and γ2 are the ratios (Nt / Nout) of the turbine rotation speed Nt to the output rotation speed (rotation speed of the output shaft 30) Nout, and the maximum value γ2max of the speed change ratios γ1 and γ2 is both greater than 1.0, so that the output shaft 30 is rotated at a reduced speed relative to the input shaft 22. The output rotation speed Nout corresponds to the vehicle speed V, and the turbine rotation speed Nt coincides with the rotation speed of the input shaft 22 (input rotation speed).

[0029] Here, as shown in FIG. 2, the hydraulic control circuit 70 is provided with linear solenoid valves SLP, SLS, SL1, SL2, SLU, as well as on-off solenoid valves SC1, SC2, SC3, a pressure regulating valve 106, a lock-up control valve 108 (control valve 108), an SC1 switching valve 110, an SC2 switching valve 112, an SC3 switching valve 114, and an evacuation travel switching valve 116.

[0030] The pressure regulating valve 106 regulates the secondary pressure Psec, which is the source pressure supplied to the control valve 108. The pressure regulating valve 106 uses, for example, the line pressure PL as the source pressure and regulates the secondary pressure Psec based on the control oil pressure Pslu of the linear solenoid valve SLU and the signal pressure of the on-off solenoid valve SC3. In this embodiment, the secondary pressure Psec is regulated to a high pressure in proportion to the control oil pressure Pslu of the linear solenoid valve SLU supplied to the control valve 108, and also when the signal pressure of the on-off solenoid valve SC3 is supplied to the control valve 108, the secondary pressure Psec is regulated to a high pressure.

[0031] The SC1 switching valve 110 is a switching valve that switches the oil path depending on the presence or absence of a signal pressure supplied from the on-off solenoid valve SC1. The SC1 switching valve 110 switches its communication state to either a first connection state indicated by a solid line or a second connection state indicated by a dashed line depending on the signal pressure from the on-off solenoid valve SC1.

[0032] In a first connection state of the SC1 switching valve 110, as shown by a solid line, the line pressure PL is output as a D-range pressure PD to the SC2 switching valve 112 and the SC3 switching valve 114. In a second connection state of the SC1 switching valve 110, as shown by a dashed line, the control oil pressure Pslu adjusted by the linear solenoid valve SLU is output to the evacuation traveling switching valve 116, and the line pressure PL is output to the SC2 switching valve 112 as an R-range pressure PR.

[0033] In this embodiment, when the on-off solenoid valve SC1 is not energized (not actuated) and no signal pressure is supplied, the SC1 switching valve 110 is in the first connection state indicated by the solid line. On the other hand, when the on-off solenoid valve SC1 is energized (actuated) and signal pressure is supplied, the SC1 switching valve 110 is in the second connection state indicated by the broken line. That is, when the D range for forward travel is selected by the shift lever 76, the on-off solenoid valve SC1 is not energized, the SC1 switching valve 110 is in the first connection state, and the D range pressure PD is output. On the other hand, when the R range for reverse travel is selected by the shift lever 76, the on-off solenoid valve SC1 is energized, the SC1 switching valve 110 is in the second connection state, and the R range pressure PR is output.

[0034] The SC2 switching valve 112 is a switching valve that switches the oil path depending on the presence or absence of a signal pressure supplied from the on-off solenoid valve SC2. The SC2 switching valve 112 is switched to either a first connection state indicated by a solid line or a second connection state indicated by a dashed line depending on the signal pressure of the on-off solenoid valve SC2.

[0035] In the first connection state of the SC2 switching valve 112, as shown by the solid lines, the D range pressure PD supplied from the SC1 switching valve 110 via the SC3 switching valve 114 is output to the evacuation driving switching valve 116, the line pressure PL is output to the linear solenoid valve SL1, the control oil pressure Psl1 adjusted by the linear solenoid valve SL1 using the line pressure PL as the original pressure is output to the synchronous mesh clutch S1 as the S1 engagement oil pressure Ps1, and the R range pressure PR supplied from the SC1 switching valve 110 is output to the SC3 switching valve 114.

[0036] In addition, in the second connection state of the SC2 switching valve 112, as shown by the dashed lines, the D-range pressure PD supplied from the SC1 switching valve 110 is output to the evacuation driving switching valve 116, the D-range pressure PD supplied from the SC1 switching valve 110 via the SC3 switching valve 114 is output to the linear solenoid valve SL1, the line pressure PL is output directly to the synchronous mesh clutch S1 as the S1 engagement oil pressure Ps1, and the control oil pressure Psl1 adjusted by the linear solenoid valve SL1 using the D-range pressure PD as the original pressure is output to the evacuation driving switching valve 116.

[0037] In this embodiment, when the on-off solenoid valve SC2 is not excited (not operated) and no signal pressure is supplied, the SC2 switching valve 112 is in the first connection state indicated by the solid line. On the other hand, when the on-off solenoid valve SC2 is excited (operated) and signal pressure is supplied, the SC2 switching valve 112 is in the second connection state indicated by the broken line. That is, the control oil pressure Psl1 adjusted by the linear solenoid valve SL1 using the line pressure PL or the D range pressure PD as the source pressure is output to the synchromesh clutch S1 as the S1 engagement oil pressure Ps1 in the first connection state, while in the second connection state, it is supplied to the forward clutch C1 as the C1 engagement oil pressure Pc1 via the evacuation travel switching valve 116. In this way, a common linear solenoid valve SL1 is used for the oil pressure control of the synchromesh clutch S1 and the forward clutch C1.

[0038] The SC3 switching valve 114 is a switching valve that switches the oil path depending on the presence or absence of a signal pressure supplied from the on-off solenoid valve SC3. The SC3 switching valve 114 switches its communication state to either a first connection state indicated by a solid line or a second connection state indicated by a dashed line depending on the signal pressure from the on-off solenoid valve SC3.

[0039] In the first connection state of the SC3 switching valve 114, as shown by a solid line, the modulator pressure PM is output to the linear solenoid valve SLU, the control oil pressure Pslu adjusted by the linear solenoid valve SLU using the modulator pressure PM as the base pressure is output as the control oil pressure for the lock-up clutch LU, and the D-range pressure PD supplied from the SC1 switching valve 110 is output to the SC2 switching valve 112. The modulator pressure PM is an oil pressure adjusted to a constant pressure by the modulator valve 118 using the line pressure PL as the base pressure. In the second connection state of the SC3 switching valve 114, as shown by a broken line, the R-range pressure PR supplied from the SC1 switching valve 110 via the SC2 switching valve 112 is output to the linear solenoid valve SLU, and the control oil pressure Pslu adjusted by the linear solenoid valve SLU using the R-range pressure PR as the base pressure is output to the reverse brake B1 as the B1 engagement oil pressure Pb1.

[0040] In this embodiment, when the on-off solenoid valve SC3 is not excited (not operated) and the signal pressure is not supplied, the SC3 switching valve 114 is in the first connection state indicated by the solid line. On the other hand, when the on-off solenoid valve SC3 is excited (operated) and the signal pressure is supplied, the SC3 switching valve 114 is in the second connection state indicated by the broken line. That is, the control oil pressure Pslu adjusted by the linear solenoid valve SLU using the modulator pressure PM or the R range pressure PR as the base pressure is output to the control valve 108 as the control oil pressure for the lock-up clutch LU in the first connection state (i.e., the on-off solenoid valve SC3 is not operated). In the second connection state (i.e., the on-off solenoid valve SC3 is operated), the control oil pressure Pslu is supplied to the reverse brake B1 as the B1 engagement oil pressure Pb1. In this way, a common linear solenoid valve SLU is used for the hydraulic control of the lock-up clutch LU and the reverse brake B1. That is, the supply destination of the control oil pressure Pslu output from the linear solenoid valve SLU is switched by the on-off solenoid valve SC3 to either the control valve 108 that controls the operating state of the lock-up clutch LU or the reverse brake B1. When driving in the R range, the on-off solenoid valve SC3 is switched to the operating state, and the SC3 switching valve 114 is switched to the second connection state shown by the dashed line. Therefore, the control oil pressure Pslu can be supplied to the reverse brake B1. The control valve 108 corresponds to the lock-up clutch circuit of the present invention, and the linear solenoid valve SLU corresponds to a specified solenoid valve of the present invention.

[0041] The evacuation travel switching valve 116 is a switching valve that switches oil paths by the control oil pressure Pslu supplied from the linear solenoid valve SLU when the SC1 switching valve 110 is in the second connection state. The evacuation travel switching valve 116 is switched to a first connection state indicated by a solid line and a second connection state indicated by a broken line. In the first connection state of the evacuation travel switching valve 116, as indicated by the solid line, the control oil pressure Psl1 by the linear solenoid valve SL1 supplied from the SC2 switching valve 112 is supplied to the forward clutch C1 as the C1 engagement oil pressure Pc1, and the D-range pressure PD supplied from the SC2 switching valve 112 is output to the linear solenoid valve SL2. In the second connection state of the evacuation traveling switching valve 116, as indicated by the dashed line, the control oil pressure Pslu by the linear solenoid valve SLU supplied from the SC1 switching valve 110 is output to the primary sheave control valve PSCV and the control valve 108, and the line pressure PL is output to the linear solenoid valve SL2. In the first connection state of the evacuation traveling switching valve 116, the linear solenoid valve SL2 regulates and controls the C2 engagement oil pressure Pc2 using the D range pressure PD as the source pressure, thereby engaging the belt running clutch C2 in accordance with the C2 engagement oil pressure Pc2, and belt running via the second power transmission path TP2 becomes possible.

[0042] The evacuation travel switching valve 116 is normally held in a first connection state indicated by a solid line, while when the belt evacuation travel mode in the D range, i.e., the fail-safe mode shown in FIG. 3, is selected, both the on-off solenoid valves SC1 and SC2 are excited (operated), both the SC1 switching valve 110 and the SC2 switching valve 112 are set to the second connection state, and the on-off solenoid valve SC3 is de-excited (not operated) and the SC3 switching valve 114 is set to the first connection state. Furthermore, a predetermined control hydraulic pressure Pslu is output from the linear solenoid valve SLU, so that the evacuation travel switching valve 116 is switched to a second connection state indicated by a broken line. In this second connection state, the line pressure PL is supplied to the linear solenoid valve SL2 via the evacuation travel switching valve 116, and the linear solenoid valve SL2 regulates and controls the C2 engagement hydraulic pressure Pc2 using the line pressure PL as the source pressure, thereby engaging the belt running clutch C2. As a result, belt running via the second power transmission path TP2, that is, belt retraction running, becomes possible.

[0043] Furthermore, in a state in which the SC1 changeover valve 110 is switched to the second connection state and the evacuation traveling changeover valve 116 is switched to the second connection state, the control oil pressure Pslu output from the linear solenoid valve SLU is supplied to the control valve 108 via the SC1 changeover valve 110 and the evacuation traveling changeover valve 116. The control valve 108 is configured such that when the control oil pressure Pslu of the linear solenoid valve SLU is supplied via the SC3 changeover valve 114, the differential pressure ΔPlu increases, whereas when the control oil pressure Pslu of the linear solenoid valve SLU is supplied via the evacuation traveling changeover valve 116, the differential pressure ΔPlu is reduced to release the lock-up clutch LU.

[0044] According to the hydraulic control circuit 70, a plurality of power transmission ranges P, N, R, and D can be established according to the operation position Psh of the shift lever 76 as shown in Fig. 3. That is, the shift lever 76 has operation positions Psh such as a D position for selecting a D (drive) range for forward driving, an R position for selecting an R (reverse) range for reverse driving, an N position for selecting an N (neutral) range for cutting off the power transmission, and a P position for selecting a P (parking) range for parking. Then, according to these operation positions Psh, the electronic control device 80 controls the solenoid valves SC1, SC2, SC3, SL1, SL2, and SLU, respectively, and switches the engagement / release states of the clutches C1, C2, and S1, and the brake B1, which are engagement devices, to establish the P range, N range, R range, and D range, which have different power transmission states.

[0045] In the P and N ranges, the clutches C1, C2 and the reverse brake B1 are released to cut off the power transmission. In the R range, the reverse brake B1 and the synchromesh clutch S1 are engaged and the clutches C1, C2 are released to enable reverse driving via the first power transmission path TP1. During the transitional period in which the R range is established, i.e., when the reverse brake B1 changes from released to engaged and when the synchromesh clutch S1 changes from released to engaged, the linear solenoid valve SLU regulates and controls the engagement oil pressure Pb1 of the reverse brake B1, and the linear solenoid valve SL1 regulates and controls the engagement oil pressure Ps1 of the synchromesh clutch S1.

[0046] In the D range, a gear driving mode, a belt low speed driving mode, a belt high speed driving mode, and a fail-safe mode (belt retract driving mode) can be selected. In the gear driving mode, the forward clutch C1 and the synchromesh clutch S1 are engaged and the belt driving clutch C2 and the reverse brake B1 are released, thereby enabling forward driving via the first power transmission path TP1. In the belt low speed driving mode, the belt driving clutch C2 and the synchromesh clutch S1 are engaged and the forward clutch C1 and the reverse brake B1 are released, thereby enabling forward driving via the second power transmission path TP2. In the belt high speed driving mode, the belt driving clutch C2 is engaged and the forward clutch C1, the reverse brake B1, and the synchromesh clutch S1 are released, thereby enabling forward driving via the second power transmission path TP2.

[0047] In the fail-safe mode, the belt driving clutch C2 and the synchromesh clutch S1 are engaged, and the forward clutch C1 and the reverse brake B1 are released, enabling forward driving via the second power transmission path TP2. When switching between the gear driving mode and the belt low-speed driving mode, a clutch-to-clutch shift (CtoC) is performed in which one of the forward clutch C1 and the belt driving clutch C2 is released and the other is engaged, and the linear solenoid valve SL1 regulates and controls the C1 engagement hydraulic pressure Pc1 of the forward clutch C1, and the linear solenoid valve SL2 regulates and controls the C2 engagement hydraulic pressure Pc2 of the belt driving clutch C2. That is, in the D range, the supply destination of the hydraulic pressure in the hydraulic control circuit 70 is switched by selectively operating a plurality of solenoid valves SC1, SC2, SC3, SL1, SL2, and SLU provided in the hydraulic control circuit 70, and the engaged / disengaged states of the hydraulic engagement devices, the clutches C1, C2, S1, and the brake B1, are switched. This causes the vehicle power transmission device 10 to switch between the first power transmission path TP1 and the second power transmission path TP2. That is, by controlling the operating states of the plurality of solenoid valves SC1, SC2, SC3, SL1, SL2, and SLU, the driving modes are switched to a plurality of driving modes.

[0048] In addition, when the lock-up clutch LU is released (L-UP OFF) during driving in the gear driving mode, the belt low-speed driving mode, and the belt high-speed driving mode, the on-off solenoid valve SC3 is switched to the operating state, and the SC3 switching valve 114 is switched to the second connection state shown by the broken line. In addition, the control oil pressure Pslu of the linear solenoid valve SLU is controlled to zero. At this time, the control valve 108 controls the differential pressure ΔPlu to zero to release the lock-up clutch LU, and a reflux control is executed to circulate the hydraulic oil regulated to the secondary pressure Psec by the pressure regulating valve 106 inside the torque converter 14.

[0049] On the other hand, when the lock-up clutch LU is engaged (L-UP ON) during driving in the gear driving mode, the belt low-speed driving mode, and the belt high-speed driving mode, the on-off solenoid valve SC3 is switched to a non-operating state, and the SC3 switching valve 114 is switched to a first connection state indicated by a solid line. At this time, the control oil pressure Pslu of the linear solenoid valve SLU can be supplied to the control valve 108 via the SC3 switching valve 114. Furthermore, the control oil pressure Pslu is output from the linear solenoid valve SLU, and the differential pressure ΔPlu is controlled to a positive value in the control valve 108. Therefore, the lock-up clutch LU is slip-engaged or fully engaged according to the control oil pressure Pslu.

[0050] Such a vehicle power transmission device 10 includes an electronic control device (control device) 80 as a controller that performs switching control among P range, R range, N range, and D range shown in Fig. 3, switching control among a plurality of driving modes in the D range, shift control and belt clamping pressure control of the belt-type continuously variable transmission 24, engagement and release control of the lock-up clutch LU, etc. The electronic control device 80 includes a so-called microcomputer having a CPU, ROM, RAM, input / output interface, etc., and performs signal processing according to a program pre-stored in the ROM while utilizing the temporary storage function of the RAM.

[0051] The electronic control device 80 receives inputs of a signal representing the operating position Psh, which is the operating position of the shift lever 76, detected from the operating position sensor 82; a signal representing the turbine rotational speed Nt [rpm], which is the rotational speed of the input shaft 22, detected from the turbine rotational speed sensor 84; a signal representing the output rotational speed Nout [rpm], which is the rotational speed of the output shaft 30, detected from the output rotational speed sensor 86; a signal representing the rotational speed N1 [rpm] of the large diameter gear 46 detected from the first rotational speed sensor 90; a signal representing the rotational speed N2 [rpm] of the idler gear 48 detected from the second rotational speed sensor 92; a signal representing the accelerator opening θacc [%] detected from the accelerator opening sensor 94; a signal representing the throttle valve opening θth [%] detected from the throttle valve opening sensor 96; and a signal representing the rotational speed Nr [rpm] of the ring gear 26r of the forward / reverse switching device 26, detected from the third rotational speed sensor 98.

[0052] As shown in FIG. 1, the electronic control device 80 functionally comprises a mode switching control means, i.e., a mode switching control unit 140, an electrical failure determination means, i.e., an electrical failure determination unit 144, and an OFF failure determination means, i.e., an OFF failure determination unit 146.

[0053] The mode switching control unit 140 switches between a plurality of driving modes shown in FIG. 3 in the D range. The mode switching control unit 140 executes mode switching control for switching between a gear driving mode in which the vehicle travels using the first power transmission path TP1 and a belt driving mode in which the vehicle travels using the second power transmission path TP2 during forward driving. For example, according to a shift map (shift conditions) determined based on driving conditions such as the accelerator opening θacc and the vehicle speed V, it performs an upshift decision for switching from the gear driving mode to the belt driving mode, or a downshift decision for switching from the belt driving mode to the gear driving mode, and executes a clutch-to-clutch shift for switching between the forward clutch C1 and the belt driving clutch C2 according to the shift decision. Specifically, it executes mode switching so that the vehicle travels in the gear driving mode at low vehicle speeds such as when the vehicle starts, and travels in the belt driving mode at vehicle speeds above a predetermined vehicle speed. In addition, in the belt driving mode, while the vehicle speed V is equal to or lower than a predetermined judgment vehicle speed Vs, a belt low vehicle speed driving mode is set in which the synchromesh clutch S1 is engaged, and when the judgment vehicle speed Vs is exceeded, a belt high vehicle speed driving mode is set in which the synchromesh clutch S1 is released.

[0054] The electrical failure determination unit 144 determines whether or not an OFF failure, in which the on-off solenoid valve SC3 is fixed on the non-operating side (OFF side) due to an electrical abnormality, has been detected while the vehicle is running. For example, the on-off solenoid valve SC3 is equipped with an abnormality detection circuit that detects electrical abnormalities in the valve. When a signal indicating that an OFF failure has occurred in the on-off solenoid valve SC3 is detected from the abnormality detection circuit, the electrical failure determination unit 144 determines that an electrical OFF failure (electrical failure) in the on-off solenoid valve SC3 has been detected.

[0055] When an electrical off-failure of the on-off solenoid valve SC3 is detected, the off-failure determination unit 146 determines whether or not an off-failure has occurred in which the on-off solenoid valve SC3 is in a non-operated state, based on the engagement state of the reverse brake B1 when switched to the R range for reverse driving. Specifically, the off-failure determination unit 146 determines whether or not an off-failure of the on-off solenoid valve SC3 has occurred, based on whether or not the reverse brake B1 is not engaged when switched to the R range. The R range corresponds to the predetermined driving range of the present invention, and the reverse brake B1 corresponds to the predetermined engagement device of the present invention.

[0056] When the range is switched to R, the on-off solenoid valve SC3 is switched to the operating state and the SC3 switching valve 114 is switched to the second connection state, so that the control oil pressure Pslu of the linear solenoid valve SLU is supplied to the reverse brake B1. If an off failure occurs in the on-off solenoid valve SC3, the SC3 switching valve 114 is in the first connection state, so that the control oil pressure Pslu is not supplied to the reverse brake B1 and the reverse brake B1 is not normally engaged. Therefore, if an off failure occurs in the on-off solenoid valve SC3, the reverse brake B1 is not engaged and reverse driving is not possible.

[0057] When the range is switched to R after an electrical OFF failure of the ON / OFF solenoid valve SC3 is detected, the OFF failure determination unit 146 determines whether the rotation speed Nr of the ring gear 26r, which is stopped by the reverse brake B1, reaches or exceeds a predetermined value. If the rotation speed Nr of the ring gear 26r reaches or exceeds a predetermined value, the OFF failure determination unit 146 detects an OFF failure of the ON / OFF solenoid valve SC3 because the reverse brake B1 is not normally engaged.

[0058] If only an electrical OFF failure of the ON-OFF solenoid valve SC3 is detected, for example, the ON-OFF solenoid valve SC3 may also have a mechanical ON failure, in which case the vehicle cannot travel even if it transitions to the fail-safe mode. In response to this, the OFF failure determination unit 146 can accurately detect an OFF failure of the ON-OFF solenoid valve SC3 by determining whether the reverse brake B1 is not engaged when the range is switched to R after an electrical OFF failure of the ON-OFF solenoid valve SC3 is detected.

[0059] When an OFF failure of the on-off solenoid valve SC3 is detected, the mode switching control unit 140 transitions to the fail-safe mode when the range is switched to the D range. Specifically, as shown in Fig. 3, the on-off solenoid valve SC1 and the on-off solenoid valve SC2 are both excited (operated), so that the SC1 switching valve 110 and the SC2 switching valve 112 are both set to the second connection state shown by the dashed line in Fig. 2. Also, because the on-off solenoid valve SC3 has an OFF failure, the SC3 switching valve 114 is set to the first connection state shown by the solid line in Fig. 2.

[0060] At this time, the modulator pressure PM adjusted by the modulator valve 118 is supplied as the source pressure to the linear solenoid valve SLU via the SC3 switching valve. Therefore, the linear solenoid valve SLU outputs the control hydraulic pressure Pslu adjusted using the modulator pressure PM as the source pressure. The control hydraulic pressure Pslu output from the linear solenoid valve SLU is supplied to the evacuation travel switching valve 116 via the SC1 switching valve 110. This control hydraulic pressure Pslu switches the evacuation travel switching valve 116 to the second connection state indicated by the dashed line in FIG. 2.

[0061] When the evacuation traveling switching valve 116 is switched to the second connection state, the line pressure PL is supplied to the linear solenoid valve SL2 via the evacuation traveling switching valve 116. Therefore, the linear solenoid valve SL2 outputs the C2 engagement oil pressure Pc2 adjusted using the line pressure PL as the source pressure. As a result, the C2 engagement oil pressure Pc2 is supplied to the belt driving clutch C2, thereby engaging the belt driving clutch C2 and enabling belt evacuation traveling.

[0062] Moreover, the control oil pressure Pslu output from the linear solenoid valve SLU is supplied to the control valve 108 via the SC3 switching valve 114. Furthermore, the control oil pressure Pslu output from the linear solenoid valve SLU is supplied to the control valve 108 via the SC1 switching valve 110 and the evacuation travel switching valve 116. At this time, in the control valve 108, the control oil pressure Pslu supplied via the SC3 switching valve 114 is offset with the control oil pressure Pslu supplied via the evacuation travel switching valve 116, so that the differential pressure ΔPlu of the lock-up clutch LU is controlled to zero. Therefore, the lock-up clutch LU is released, and the hydraulic oil adjusted to the secondary pressure Psec by the pressure regulating valve 106 is supplied to the torque converter 14 via the control valve 108, so that the hydraulic oil circulates within the torque converter 14. As a result, even if an off failure occurs in the on-off solenoid valve SC3, the driving mode is transitioned to the fail-safe mode, making it possible to perform belt evacuation driving in which the lock-up clutch LU is released, thereby protecting the lock-up clutch LU.

[0063] 4 is a flowchart explaining the control function of the electronic control device 80, which reliably detects an OFF failure of the on-off solenoid valve SC3 while the vehicle is running, and switches to a fail-safe mode in which the lock-up clutch LU is released and the vehicle runs after the OFF failure of the on-off solenoid valve SC3. This flowchart is repeatedly executed while the vehicle is running.

[0064] First, in step S10 (hereinafter, step is omitted) corresponding to the control function of the electrical failure determination unit 144, it is determined whether or not an electrical OFF failure of the ON / OFF solenoid valve SC3 has been detected. If the determination in S10 is negative, this routine ends. If the determination in S10 is positive, in S20 corresponding to the control function of the OFF failure determination unit 146, it is determined whether or not the vehicle is unable to travel in reverse when switched to the R range (reverse travel range), that is, whether or not the reverse brake B1 is not engaged. If the determination in S20 is negative, this routine ends. If the determination in S20 is positive, the OFF failure of the ON / OFF solenoid valve SC3 is confirmed, and in S30 corresponding to the control function of the mode switching control unit 140, the travel mode is shifted to the fail-safe mode. As a result, belt evacuation travel is performed by the second power transmission path TP2. At this time, the lock-up clutch LU is released, thereby protecting the lock-up clutch LU.

[0065] As described above, according to this embodiment, when an electrical failure of the on-off solenoid valve SC3 is detected, an off failure of the on-off solenoid valve SC3 is accurately detected based on the engagement state of the reverse brake B1 when the range is switched to R. Also, when an off failure of the on-off solenoid valve SC3 is detected, the system transitions to a fail-safe mode in which the lock-up clutch LU is released, enabling evacuation travel. Also, since the lock-up clutch LU is released during evacuation travel, the lock-up clutch LU is protected and evacuation travel performance is improved.

[0066] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0067] For example, in the above embodiment, when the range is switched to the R range (reverse driving range), the reverse brake B1 is engaged as the predetermined engagement device, but the present invention is not necessarily limited to a brake. For example, when the range is switched to the R range (reverse driving range), a clutch that disconnects rotating elements may be engaged as the predetermined engagement device.

[0068] In the above embodiment, the determination as to whether the reverse brake B1 is not engaged is based on the rotation speed Nr of the ring gear 26r that is stopped by the reverse brake B1 when the range is switched to R, but the present invention is not necessarily limited to this. For example, the determination as to whether the reverse brake B1 is not engaged may be based on the value of the B1 engagement hydraulic pressure Pb1 of the reverse brake B1.

[0069] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0070] 10: Vehicle power transmission device 80: Electronic control device (control device) 108: Lock-up control valve (lock-up clutch circuit) LU: Lock-up clutch B1: Reverse brake (predetermined engagement device) SC1: On-off solenoid valve (multiple solenoid valves) SC2: On-off solenoid valve (multiple solenoid valves) SC3: On-off solenoid valve (on-off solenoid valve, multiple solenoid valves) SL1: Linear solenoid valve (multiple solenoid valves) SL2: Linear solenoid valve (multiple solenoid valves) SLU: Linear solenoid valve (single solenoid valve, multiple solenoid valves)

Claims

[Claim 1] A control device for a vehicle power transmission device, which is applied to a vehicle power transmission device in which a plurality of driving modes are switched by switching the operating states of a plurality of solenoid valves, and has an on-off solenoid valve for switching a supply destination of a control hydraulic pressure output from a predetermined solenoid valve to either a lock-up clutch circuit that controls a lock-up clutch or a predetermined engagement device, the on-off solenoid valve is configured such that the control oil pressure is supplied to the lock-up clutch circuit in a non-operated state, and the control oil pressure is supplied to the predetermined engagement device in an operated state, the on-off solenoid valve is switched to a non-operating state when the lock-up clutch is engaged, and is switched to an operating state when the lock-up clutch is released, The on-off solenoid valve is switched to an operating state when the vehicle is traveling in a predetermined traveling range, When an electrical failure of the on-off solenoid valve is detected, it is determined whether or not an off failure has occurred in which the on-off solenoid valve is in a non-operated state based on the engagement state of the predetermined engagement device when the vehicle is switched to the predetermined driving range, and when an off failure of the on-off solenoid valve is detected, the vehicle is configured to transition to a fail-safe mode in which the vehicle is driven with the lock-up clutch released even if the on-off solenoid valve is in a non-operated state. A control device for a vehicle power transmission device comprising:

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