JP5233793B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device, and in particular, a power generation source while changing a power transmission path from an input shaft connected to a power generation source to an output shaft by switching an engagement state of at least one friction engagement element. The present invention relates to a power transmission device that transmits motive power from a motor to an output shaft.

  Conventionally, as a linear solenoid driving device for driving a linear solenoid valve of an electronically controlled brake system, a PWM signal generating unit for controlling a current value flowing through the solenoid, a solenoid driving circuit, a solenoid driving transistor, and a solenoid flowing A device is known that includes a current monitor that monitors a current value and outputs the monitored current with a predetermined gain characteristic and feeds it back to a PWM signal generation unit or the like (see, for example, Patent Document 1). In this linear solenoid driving device, the gain characteristic of the current monitor is changed according to the magnitude of the current value flowing through the solenoid, that is, the accuracy of necessary current control.

JP 2007-282433 A

  The electromagnetic valve such as the linear solenoid valve as described above is used not only for supplying an electronically controlled brake system but also for supplying a working fluid to a friction engagement element such as a clutch or a brake in a power transmission device such as an automatic transmission. In a power transmission device, a working fluid having a pressure higher than that required at the time of steady operation from the solenoid valve to the friction engagement element while ensuring the pressure regulation accuracy of the solenoid valve in order to realize smooth and shock-free shifting. It is necessary to supply the working fluid promptly from the electromagnetic valve to the friction engagement element. However, depending on the maximum output pressure required for the solenoid valve, it is necessary to control a relatively large pressure fluctuation (eg, about 200 kPa) within a relatively narrow current range (eg, about 0.1 A). Output gain (degree of change in output pressure with respect to current change) becomes relatively high, and even if the gain characteristics of the current monitor are changed as in the above-mentioned conventional device, the pressure regulation accuracy of the solenoid valve can be secured satisfactorily. There is a risk of disappearing. On the other hand, if the output gain of the solenoid valve is lowered to improve the pressure regulation accuracy of the solenoid valve, the maximum output pressure of the solenoid valve will be reduced, or the working fluid will be quickly moved from the solenoid valve to the friction engagement element. May not be able to be supplied.

  Therefore, the power transmission device according to the present invention suppresses the decrease in the maximum output pressure of the solenoid valve and the inability to quickly supply the working fluid from the solenoid valve to the friction engagement element, while adjusting the pressure of the solenoid valve. The main purpose is to ensure accuracy.

  The power transmission device according to the present invention employs the following means in order to achieve the main object.

The power transmission device according to the present invention includes:
The power from the power generation source is changed while changing the power transmission path from the input shaft connected to the power generation source mounted on the vehicle to the output shaft by switching the engagement state of at least one friction engagement element. A power transmission device for transmitting to an output shaft,
A normally closed solenoid valve capable of regulating and outputting a working fluid to the friction engagement element;
A solenoid valve capable of regulating and outputting a working fluid to the friction engagement element;
A switching element connected to the electromagnetic part of the solenoid valve;
When the predetermined condition for temporarily and quickly opening the solenoid valve is not satisfied, the average value of the current flowing through the electromagnetic unit does not exceed the predetermined current value according to the output pressure required for the solenoid valve. The switching ratio of the switching element is controlled so that a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit, and the predetermined condition is satisfied. Sometimes, a higher duty ratio and lower frequency are set than when the predetermined condition is not satisfied so that an average value of the current flowing through the electromagnetic unit exceeds the predetermined current value and becomes a value corresponding to the required output pressure. And switching control of the switching element so that a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit. And control means,
Is provided.

  In this power transmission device, when a predetermined condition for temporarily and quickly opening the solenoid valve is not satisfied, an output required for the solenoid valve without the average value of the current flowing through the electromagnetic unit exceeding the predetermined current value. The duty ratio and the frequency are set so as to become a value corresponding to the pressure, and the switching element is subjected to switching control so that a rectangular wave voltage having the set duty ratio and frequency is applied to the electromagnetic unit. Also, when the predetermined condition is satisfied, the average value of the current flowing through the electromagnetic unit exceeds the predetermined current value and becomes a value corresponding to the required output pressure, and a higher duty ratio and lower than when the predetermined condition is not satisfied. The switching element is subjected to switching control so that a rectangular wave voltage having the set duty ratio and frequency is applied to the electromagnetic unit. In this way, a larger output pressure can be obtained from the solenoid valve by quickly opening the solenoid valve so that the value of the current flowing through the electromagnetic unit exceeds the predetermined current value when the predetermined condition is satisfied. If the working fluid is quickly supplied from the solenoid valve to the friction engagement element, it is not necessary to temporarily and quickly increase the opening of the solenoid valve, that is, the output of the solenoid valve in accordance with the normal operation. Since the gain (degree of change in output pressure with respect to current change) can be set low, it is possible to ensure the pressure adjustment accuracy of the solenoid valve. Therefore, in this power transmission device, the pressure regulation accuracy of the solenoid valve is increased while suppressing the decrease in the maximum output pressure of the solenoid valve and the failure to quickly supply the working fluid from the solenoid valve to the friction engagement element. It can be secured. Note that the duty ratio = 100% is included in the higher duty ratio than when the predetermined condition is not satisfied.

  Further, the predetermined current value may be a normal maximum current value allowed for the electromagnetic part of the electromagnetic valve, and the control means is configured so that when the predetermined condition is satisfied, the power supply state to the electromagnetic part is A high duty ratio and a low frequency may be set so as to be in an overcurrent state compared to when the predetermined condition is not satisfied. In this way, if the average value of the current flowing through the electromagnetic part exceeds the normal maximum current value when the predetermined condition is satisfied and the power supply state to the electromagnetic part is allowed to become an overcurrent state, a wider current can be obtained. Since relatively small pressure fluctuations can be controlled within the range, the output gain of the solenoid valve can be lowered, thereby ensuring good pressure regulation accuracy of the solenoid valve. Also, if the power supply state to the electromagnetic part is allowed to become an overcurrent state, the solenoid valve is quickly opened to a large opening, thereby further increasing the displacement of the solenoid valve spool and increasing the output pressure from the solenoid valve. Or the working fluid can be quickly supplied from the electromagnetic valve to the friction engagement element. Therefore, according to this power transmission device, the pressure regulation of the solenoid valve is suppressed while suppressing the decrease in the maximum output pressure of the solenoid valve and the failure to quickly supply the working fluid from the solenoid valve to the friction engagement element. It becomes possible to ensure good accuracy. In this power transmission device, the solenoid part of the solenoid valve is temporarily in an overcurrent state, so measures to improve the durability against heat generation of the solenoid part are taken as necessary. Is enough. When the normal maximum current value itself is ensured to be large to some extent, the predetermined current value may be a value less than the normal maximum current value.

  Furthermore, the predetermined condition may be satisfied when a stall start of the vehicle is requested, and may not be satisfied when the stall state is completed. In other words, when the vehicle stall start is requested, the switching element is controlled so that the average value of the current flowing through the electromagnetic part exceeds the normal maximum current value and the power supply state to the electromagnetic part becomes an overcurrent state. If a larger output pressure is obtained from the solenoid valve, a high-pressure working fluid required at the time of stall start can be supplied from the solenoid valve to the fluid pressure clutch used at the time of start, while the output is also adjusted during normal operation. It is possible to secure a good pressure regulation accuracy of the solenoid valve by setting the gain low. In addition, since the frequency with which stall start is performed is relatively low, it is considered that the durability deterioration due to heat generation of the electromagnetic part when an overcurrent state occurs can be ignored in practice.

  The power transmission device includes a shift unit that allows selection of an arbitrary shift range from a plurality of shift ranges including at least a neutral range and a traveling range, and a temperature acquisition unit that acquires the temperature of the working fluid. The friction engagement element may be a fluid pressure clutch to be engaged when the shift range is switched from the neutral range to the travel range, and the predetermined condition is The shift range may be established when the shift range is switched from the neutral range to the travel range in a state where the temperature acquired by the temperature acquisition unit is equal to or lower than a predetermined temperature. That is, when switching from the neutral range to the driving range in the low temperature state, the switching element is set so that the average value of the current flowing through the electromagnetic part exceeds the normal maximum current value and the power supply state to the electromagnetic part becomes an overcurrent state. By controlling the solenoid valve to a large opening quickly, even if the working fluid is in a low temperature state where the viscosity of the fluid is low, the fluid pressure clutch to be engaged with switching from the neutral range to the traveling range It is possible to quickly supply (fill) the working fluid and improve the shift response. In this case, since the electromagnetic part of the solenoid valve is in an overcurrent state and the amount of heat generated in the electromagnetic part increases, the temperature generated by the electromagnetic part is accelerated and the viscosity of the working fluid is increased. It can also be reduced. And since the output gain of a solenoid valve can be set low according to the operation | movement at the normal temperature, it becomes possible to ensure the pressure regulation precision of a solenoid valve favorable by it.

  In this case, the predetermined condition may not be satisfied when a predetermined time has elapsed after switching from the neutral range to the travel range.

  Further, the power transmission device further includes a current sensor that acquires a value of a current flowing through the electromagnetic unit, and the control unit is configured to output a current value corresponding to the required output pressure and the current when the predetermined condition is not satisfied. The duty ratio and the frequency are set so that there is no deviation from the current value detected by the sensor, and when the predetermined condition is satisfied, the duty ratio and the frequency are not used without using the current value detected by the current sensor. A frequency may be set. As a result, when the predetermined condition is not satisfied, the solenoid valve can be controlled more accurately so as to output a working fluid having a pressure corresponding to the required output pressure. When the predetermined condition is satisfied, The opening degree of the valve can be quickly increased.

It is a schematic block diagram of the motor vehicle 10 which is a vehicle carrying the power transmission device 20 which concerns on one Example of this invention. It is a schematic block diagram of the power transmission device 20 of an Example. 3 is an operation table showing the relationship between each shift stage of an automatic transmission 25 included in the power transmission device 20 of the embodiment and the operation states of the clutch and the brake B. It is a systematic diagram which shows the outline | summary of the hydraulic control unit 50 contained in the power transmission device 20 of an Example. It is a schematic block diagram which shows a part of drive circuit 60 used for driving the linear solenoid valve 54 grade | etc.,. It is explanatory drawing which shows the correlation with the electric current applied to the electromagnetic parts 544 grade | etc., Such as the linear solenoid valve 54, and the pressure of the hydraulic fluid output from the output port Pout. (A) And (b) is explanatory drawing which illustrates the rectangular wave voltage applied to electromagnetic parts 544 grade | etc., Such as the linear solenoid valve 54 grade | etc.,. It is a flowchart which shows an example of the control routine at the time of start. It is a flowchart which shows an example of the control routine at the time of ND switching.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a schematic configuration diagram of an automobile 10 that is a vehicle on which a power transmission device 20 according to an embodiment of the present invention is mounted. FIG. 2 is a schematic configuration diagram of the power transmission device 20 mounted on the automobile 10. is there. An automobile 10 shown in these drawings includes an engine 12 that is an internal combustion engine that outputs power by explosion combustion of a mixture of hydrocarbon-based fuel such as gasoline and light oil and air, and electronic control for the engine that controls the operation of the engine 12. A unit (hereinafter referred to as “engine ECU”) 14, a brake electronic control unit (hereinafter referred to as “brake ECU”) 16 for controlling an electronically controlled hydraulic brake unit (not shown), a torque converter 23 and a stepped automatic transmission Machine 25, and a shift electronic control unit (hereinafter referred to as "shift ECU") 21 for controlling them, is connected to the crankshaft of engine 12 and transmits power from engine 12 to left and right drive wheels DW. The power transmission device 20 is provided.

  As shown in FIG. 1, the engine ECU 14 includes an accelerator opening Acc from an accelerator pedal position sensor 92 that detects a depression amount (operation amount) of an accelerator pedal 91, a vehicle speed V from a vehicle speed sensor 99, and a rotation speed of a crankshaft. A signal from various sensors such as a rotational speed sensor (not shown) for detecting the engine, a signal from the brake ECU 16 and the shift ECU 21 and the like are input, and based on these signals, the engine ECU 14 Controls fuel injection valves, spark plugs, etc. The brake ECU 16 includes a master cylinder pressure detected by the master cylinder pressure sensor 94 when the brake pedal 93 is depressed, a vehicle speed V from the vehicle speed sensor 99, signals from various sensors (not shown), an engine ECU 14 and a shift ECU 21. The brake ECU 16 controls a brake actuator (hydraulic actuator) (not shown) and the like based on these signals.

  The transmission ECU 21 of the power transmission device 20 is housed inside the transmission case. The shift ECU 21 includes a shift range SR from a shift range sensor 96 that detects an operation position of the shift lever 95 for selecting a desired shift range from among a plurality of shift ranges, and an oil temperature that detects the temperature of hydraulic oil. The oil temperature T from the sensor 97, the vehicle speed V from the vehicle speed sensor 99, signals from various sensors (not shown), signals from the engine ECU 14 and the brake ECU 16 and the like are input, and the transmission ECU 21 performs torque based on these signals. The converter 23, the automatic transmission 25, etc. are controlled. Here, in the automobile 10 of the embodiment, as the shift range SR of the shift lever 95, a parking range (P range) selected at the time of parking, a reverse range for reverse travel (R range), and a neutral range (N range). In addition to the normal forward drive range (D range), a sports range (S range) that allows the driver to select an arbitrary shift stage from a plurality of predetermined shift stages, an upshift instruction Position and downshift instruction position are prepared.

  The engine ECU 14, the brake ECU 16, and the shift ECU 21 are configured as a microprocessor centered on a CPU (not shown). In addition to the CPU, a ROM that stores a processing program, a RAM that temporarily stores data, an input / output A port and a communication port (both not shown). The engine ECU 14, the brake ECU 16 and the speed change ECU 21 are connected to each other via a bus line or the like, and exchange of data necessary for control is executed at any time between these ECUs.

  The power transmission device 20 includes a torque converter 23 housed in the transmission case, an oil pump 24, an automatic transmission 25, a differential mechanism (differential gear) 29, and the like. The torque converter 23 includes an input-side pump impeller 23a connected to the crankshaft of the engine 12, and an output-side turbine runner 23b fixed to the input shaft 26 of the automatic transmission 25, and further has a lock-up clutch function. It is what you have. The oil pump 24 is configured as a gear pump including a pump assembly including a pump body and a pump cover, and an external gear connected to the pump impeller 23a of the torque converter 23 via a hub. When the external gear is rotated by the power from the engine 12, hydraulic oil (ATF) stored in the oil pan 45 (both see FIG. 4) is sucked and discharged by the oil pump 24 via the strainer 40, As a result, the hydraulic pressure required by the torque converter 23 and the automatic transmission 25 can be generated, or hydraulic oil can be supplied to lubricated parts such as various bearings.

  The automatic transmission 25 is configured as a stepped transmission with six speeds. As shown in FIG. 2, the single pinion planetary gear mechanism 30, the Ravigneaux planetary gear mechanism 35, and the input side to the output side are provided. Including three clutches C1, C2 and C3, two brakes B1 and B2, and a one-way clutch F1 for changing the power transmission path of The single pinion type planetary gear mechanism 30 includes a sun gear 31 that is an external gear fixed to the transmission case, and a ring gear 32 that is concentrically arranged with the sun gear 31 and connected to the input shaft 26. A plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32 and a carrier 34 that holds the plurality of pinion gears 33 so as to rotate and revolve freely. The Ravigneaux planetary gear mechanism 35 includes two sun gears 36a and 36b that are external gears, a ring gear 37 that is an internal gear fixed to the output shaft 27 of the automatic transmission 25, and a plurality of short gears that mesh with the sun gear 36a. A plurality of long pinion gears 38b meshing with the pinion gear 38a, the sun gear 36b and the plurality of short pinion gears 38a and meshing with the ring gear 37, and a plurality of short pinion gears 38a and a plurality of long pinion gears 38b connected to each other are held rotatably. And a carrier 39 supported by the case via the one-way clutch F1. The output shaft 27 of the automatic transmission 25 is connected to the drive wheels DW via a gear mechanism 28 and a differential mechanism 29.

  The clutch C1 is a hydraulic clutch that can fasten the carrier 34 of the single pinion type planetary gear mechanism 30 and the sun gear 36a of the Ravigneaux type planetary gear mechanism 35 and release the fastening. The clutch C2 is a hydraulic clutch that can fasten the input shaft 26 and the carrier 39 of the Ravigneaux planetary gear mechanism 35 and release the fastening. The clutch C3 is a hydraulic clutch that can fasten the carrier 34 of the single pinion planetary gear mechanism 30 and the sun gear 36b of the Ravigneaux planetary gear mechanism 35 and release the fastening. The brake B1 is a hydraulic clutch capable of fixing the sun gear 36b of the Ravigneaux type planetary gear mechanism 35 to the case and releasing the sun gear 36b from the case. The brake B2 is a hydraulic clutch that can fix the carrier 39 of the Ravigneaux type planetary gear mechanism 35 to the case and release the carrier 39 from the case. These clutches C <b> 1 to C <b> 3 and brakes B <b> 1 and B <b> 2 operate by receiving and supplying hydraulic oil from the hydraulic control unit 50. FIG. 3 shows an operation table showing the relationship between the respective shift stages of the automatic transmission 25 and the operation states of the clutches C1 to C3 and the brakes B1 and B2. The automatic transmission 25 provides the first to sixth forward speeds and the first reverse speed by setting the clutches C1 to C3 and the brakes B1 and B2 to the states shown in the operation table of FIG.

  As shown in FIG. 4, the hydraulic control unit 50 is connected to the oil pump 24 that sucks and discharges hydraulic oil from the oil pan 45 via the strainer 40 using the power from the engine 12. A linear solenoid valve 51 that regulates and outputs hydraulic oil from the oil pump 24 side (pressure regulating valve (not shown)), and is driven by the linear solenoid valve 51 to adjust the pressure of the hydraulic oil from the oil pump 24 to adjust the line pressure. According to the operation position of the regulator valve 52 for generating the PL and the shift lever 95, the hydraulic oil from the regulator valve 52 can be supplied to the clutches C1 to C3 and the brakes B1 and B2, and the hydraulic oil is supplied to the clutch C1 and the like. Manual valve 53 that can be stopped and hydraulic oil from manual valve 53 ( The normally closed linear solenoid valve 54 that can regulate and output the in-pressure PL) to the clutch C1 side, and the normally closed that can regulate the hydraulic oil (line pressure PL) from the manual valve 53 and output it to the brake B1 side A linear solenoid valve 55 of the type, and a plurality of linear solenoid valves (not shown) capable of regulating hydraulic oil (line pressure PL) from the manual valve 53 and outputting it to the corresponding ones of the clutches C2, C2 and the brake B2. including. 4 illustrates only the hydraulic system of the clutch C1 and the brake B1, but the same hydraulic system is configured for the other clutches C2, C3 and the brake B2.

  The linear solenoid valves 54 and 55 include hollow sleeves 541 and 551 having an input port Pin, an output port Pout, and a drain port Pd, and spools 542 and 552 that are disposed in the sleeves 541 and 551 and are slidable in the axial direction. And springs 543 and 553 that urge the spools 542 and 552 in the axial direction, and electromagnetic portions 544 and 554 that can apply thrust to the spools 542 and 552 so as to resist the urging force of the springs 543 and 553. Have. The linear solenoid valves (not shown) of the linear solenoid valves 54 and 55, the clutches C2 and C3, and the brake B2 are driven by a drive circuit 60 controlled by the transmission ECU 21. FIG. 5 illustrates an electromagnetic drive system of the linear solenoid valve 54 corresponding to the clutch C <b> 1 in the drive circuit 60. As shown in the figure, the drive circuit 60 is connected to, for example, a DC 12V DC power supply 61 and a coil 545 of the electromagnetic part 544 of the linear solenoid valve 54, and the ratio of ON time is adjusted (switching control) by the shift ECU 21. ) Includes a transistor 62 as a switching element and a current sensor 63 for detecting a current flowing through a coil 545. The linear solenoid valve 55 corresponding to the brake B1 and the other solenoids C2 and C3 and the linear solenoid valve corresponding to the brake B2 also have an electromagnetic drive system similar to that shown in FIG. In the linear solenoid valve 54 or the like having such a configuration, if the transistor 62 is switching-controlled so that the thrust applied to the spool 542 changes and a voltage (rectangular wave voltage) is applied to the coil 545 of the electromagnetic unit 544, Part of the hydraulic fluid that has flowed into the input port Pin is discharged from the drain port Pd, and the hydraulic fluid that has been regulated thereby can be output from the output port Pout.

  Here, in the linear solenoid valves 54 and 55 of the embodiment, the average value of the current applied to the coils 545 and 555 of the electromagnetic portions 544 and 554 and the pressure (output pressure) of the hydraulic oil output from the output port Pout are obtained. The strokes of the spools 542 and 552, the area difference (feedback pressure) between the large-diameter land and the small-diameter land of the spools 542 and 552, the spring constant of the springs 543 and 553, and the electromagnetic unit 544 so as to have the correlation shown in FIG. Specifications such as material and performance of 554 (coils 545 and 555), a control mode of the drive circuit 60, and the like are determined. That is, in the linear solenoid valves 54 and 55 of the embodiment, the average value of the current flowing through the coils 545 and 555 of the electromagnetic portions 544 and 554 is a value slightly smaller than the normal maximum current value (for example, a value of about 1.0 A) ( For example, the engagement pressure when the clutch C1 or the brake B1 is engaged is output at the time of about 0.9A, and the average value of the current flowing through the coils 545 and 555 of the electromagnetic portions 544 and 554 is the normal maximum current. When a predetermined value (for example, about 2.0 A) exceeding the value Aref is reached, the valve is fully opened and the maximum pressure Pmax (line pressure PL) is output. As a result, as shown by a two-dot chain line in FIG. 6, when the average value of the current flowing through the coil of the electromagnetic part reaches the normal maximum current value Aref, it is fully opened and the maximum pressure Pmax (line pressure PL) is output. Compared to a linear solenoid valve with characteristics, the output gain of the linear solenoid valves 54 and 55 (the degree of change in the output pressure with respect to the current change) when the output pressure is equal to or lower than the pressure corresponding to the normal maximum current value Aref is reduced. Therefore, it is possible to ensure good pressure regulation accuracy. Although the pressure corresponding to the normal maximum current value Aref is arbitrarily determined within a range smaller than the maximum pressure required for the linear solenoid valves 54 and 55, the output gain of the linear solenoid valves 54 and 55 is reduced as much as possible. From this point of view, it is preferable to make the value somewhat lower.

  In the embodiment, when the required output pressure, which is the output pressure required for the linear solenoid valves 54 and 55, is equal to or lower than the pressure corresponding to the normal maximum current value Aref, the coils 545 and 555 of the electromagnetic portions 544 and 554 are turned on. The target duty ratio (for example, about 50 to 70%) is set so that the average value of the flowing current does not exceed the normal maximum current value Aref and becomes a value corresponding to the required output pressure, and is relatively high with the target duty ratio The transistor 62 of the drive circuit 60 is subjected to switching control so that a rectangular wave voltage (see FIG. 7A) having a constant frequency (for example, about 300 Hz) is applied to the coils 545 and 555 of the electromagnetic units 544 and 554. (Hereinafter, such a control mode of the drive circuit 60 is referred to as “normal mode”). Under this normal mode, the transmission ECU 21 sets the required output pressure for the linear solenoid valves 54 and 55 using predetermined data and a predetermined map, and then applies the required output pressure to the coils 545 and 555. A required current value corresponding to the required output pressure is obtained using a map that defines the relationship with the value of the current to be applied. Then, the target duty ratio is set in accordance with a relational expression for feedback control that eliminates the deviation between the requested current value and the current value detected by the current sensor 63. That is, under the normal mode, current feedback is performed so that the deviation between the required current value and the current value detected by the current sensor 63 is eliminated.

  When the required output pressure for the linear solenoid valves 54 and 55 exceeds the pressure corresponding to the normal maximum current value Aref, the average value of the current flowing through the coils 545 and 555 of the electromagnetic units 544 and 554 exceeds the normal maximum current value Aref. Thus, a higher target duty ratio and a lower constant than in the execution of the normal mode can be obtained so that a larger output pressure can be obtained from the linear solenoid valves 54 and 55 when the power supply state to the coils 545 and 555 becomes an overcurrent state. The drive circuit 60 is set such that a rectangular wave voltage (see FIG. 7B) having a target duty ratio and frequency is applied to the coils 545 and 555 of the electromagnetic units 544 and 554. The transistor 62 is controlled to be switched (hereinafter, the control mode of the drive circuit 60 is That the over-current mode "). Under this overcurrent mode, the shift ECU 21 sets the required output pressure for the linear solenoid valves 54 and 55 using predetermined data and a predetermined map, and then sets the required output pressure and the coils 545 and 555. A required current value corresponding to the required output pressure is obtained using a map that defines the relationship with the value of the current to be applied to the current, and a target duty ratio corresponding to the required current value is set without executing current feedback. In the automatic transmission 25 according to the embodiment, the other linear solenoid valves corresponding to the clutches C2, C3 and the brake B2 other than the clutch C1 and the brake B1 have the same characteristics as the linear solenoid valves 54 and 55. Various specifications and the control mode of the drive circuit 60 are determined. Needless to say, not only the duty ratio but also the frequency may be changed in both the normal mode and the overcurrent mode.

  Next, the operation of the automatic transmission 25 included in the power transmission device 20 of the embodiment will be described.

  FIG. 8 shows a start time control routine executed by the shift ECU 21 from the time when the accelerator pedal 91 is depressed after the shift range is switched from the N range to the D range or the R range with the brake pedal 93 depressed. It is a flowchart which shows an example. At the start of the start-up control routine, the CPU (not shown) of the shift ECU 21 first obtains necessary data such as the shift range SR from the shift range sensor 96, the vehicle speed V from the vehicle speed sensor 99, and the accelerator opening Acc from the engine ECU 14. After the input, it is determined whether or not a stall start of the automobile 10 is requested by the driver based on the input data (steps S100 and S110). In step S110, when the shift range is in the D range or the R range, the accelerator opening Acc is equal to or greater than the predetermined value Aref, and the vehicle speed V is 0 (the brake pedal 93 is depressed and the vehicle is stopped). It is determined that a stall start of the automobile 10 is requested by the driver. When it is determined in step S110 that the driver has not requested the stall start of the automobile 10, normal start time control (step S160) is executed, and when normal start time control is completed. This routine ends.

  On the other hand, if it is determined in step S110 that the driver has requested that the vehicle 10 be stalled, the predetermined current feedback flag is turned off to prohibit the execution of the current feedback. (Step S120), the transistor 62 of the drive circuit 60 is set so that the output pressure of the linear solenoid valve 54 corresponding to the clutch C1 to be engaged when the vehicle 10 starts is reached to the maximum output pressure (line pressure) with a steep slope. Switching control is performed (step S130). When the process of step S130 is executed in response to the stall start request, a high pressure is required to maintain the engagement of the clutch C1, and therefore the required output pressure for the linear solenoid valve 54 is the normal maximum current value. The pressure corresponding to Aref is exceeded, and the required opening for the linear solenoid valve 54 is almost fully opened. Prior to the process of step S130, the current feedback flag is turned off. For this reason, in step S130, the shift ECU 21 has a higher duty ratio (finally, for example, 90%) than that in the normal mode corresponding to the gradient and the required output pressure (maximum output pressure) in the overcurrent mode. %) And a low-frequency (for example, 10 Hz) rectangular wave voltage (see FIG. 7B) is applied to the coil 545 of the electromagnetic unit 544 so as to switch the transistor 62 of the drive circuit 60. As a result, it becomes possible to apply a larger hydraulic pressure from the linear solenoid valve 54 to the clutch C1 in response to a stall start request, to quickly engage the clutch C1, and to reliably maintain the engaged state. . The process of step S130 is executed until it is determined in step S140 that the stalled state has ended, and when it is determined in step S140 that the stalled state has ended, the current feedback flag is turned on again (step S150). This routine ends. In step S140 of the embodiment, the input shaft rotation speed Nin and the output shaft rotation speed calculated based on the detection values of a rotation position detection sensor (not shown) provided on the input shaft 26 and the output shaft 27 of the automatic transmission 25. When the deviation from Nout becomes approximately 0 (entering within a predetermined range), it is determined that the stall condition has ended. In step S130, the duty ratio of the rectangular wave voltage may be 100%.

  Next, the operation of the automatic transmission 25 when the shift range is switched from the N range to the D range will be described with reference to FIG. FIG. 9 is a flowchart showing an example of an N-D switching control routine executed by the shift ECU 21 from the time when the shift range is switched from the N range to the D range.

  At the start of the ND switching control routine, the CPU (not shown) of the speed change ECU 21 first inputs an oil temperature T from an oil temperature sensor 97 provided at an appropriate position of the hydraulic control unit 50, and then the oil temperature. T is compared with a predetermined reference temperature (for example, a temperature of about −20 to −30 ° C.) (step S200), and it is determined whether or not the hydraulic oil is in a very low temperature state (step S210). When it is determined in step S210 that the oil temperature T is higher than the reference temperature and the hydraulic oil is not in an extremely low temperature state, normal ND switching control (step S280) is executed, This routine ends when the ND switching control is completed.

  On the other hand, if it is determined in step S210 that the hydraulic oil is in an extremely low temperature state, the current feedback flag is turned off (step S220) to prohibit the execution of the current feedback described above, and the shift range. Transistor 62 of the drive circuit 60 so that the opening degree of the linear solenoid valve 54 corresponding to the clutch C1 to be engaged when the engine is switched from the N range to the D range reaches a maximum opening degree (fully opened) with a steep slope. Is switched (step S230). When the process of step S230 is executed, if the required opening degree for the linear solenoid valve 54 is converted into the required output pressure, the pressure corresponding to the normal maximum current value Aref will be exceeded, and the current feedback flag is turned off. Has been. For this reason, in step S230, the shift ECU 21 has a rectangular wave voltage (e.g., 90%) and a low frequency (e.g., 10 Hz) in the overcurrent mode with a higher duty ratio (e.g., 90%) than in the normal mode. 7 (b)) is applied to the coil 545 of the electromagnetic unit 544, and the transistor 62 of the drive circuit 60 is subjected to switching control. As a result, when the shift range is switched from the N range to the D range in a cryogenic state where the viscosity of the hydraulic oil is increased, the opening of the linear solenoid valve 54 is quickly fully opened, and the clutch C1 is quickly operated. It becomes possible to improve the shift response by supplying (filling) oil. The process of step S230 is executed until it is determined in step S240 that a predetermined time (for example, about 1 second) has elapsed since the start of the process. In step S230, the duty ratio of the rectangular wave voltage may be 100%.

  If it is determined in step S240 that the predetermined time has elapsed, the current feedback flag is turned on again (step S250), and the output pressure (clutch pressure) is swept down to decrease the output pressure of the linear solenoid valve 54 with a predetermined gradient. Processing is executed (step S260). When the sweep down process in step S260 is executed, the required output pressure for the linear solenoid valve 55 gradually decreases, and the current feedback flag is turned on in step S250. When the output pressure is equal to or lower than the pressure corresponding to the normal maximum current value Aref, the average value of the current flowing through the coil 545 of the electromagnetic unit 544 while executing the current feedback using the current value from the current sensor 63 in the normal mode. Is set to a value corresponding to the required output pressure without exceeding the normal maximum current value Aref, for example, within a range of 50 to 70%, and the target duty ratio and a relatively high constant frequency (for example, Of the drive circuit 60 so that a rectangular wave voltage having a frequency of about 300 Hz is applied to the coil 545. The switching control of the transistor 62. Thereby, in the automatic transmission 25 of an Example, it becomes possible to perform a sweep down process smoothly. Such a sweep-down process in step S260 is executed until the input shaft speed Ni of the automatic transmission 25 reaches a value of 0, and this routine is performed when it is determined in step S270 that the input shaft speed Ni has a value of 0. Will end.

  The operation of the automatic transmission 25 when the shift range is switched from the N range to the D range while the oil temperature T is below the reference temperature has been described so far. However, the oil temperature T is below the reference temperature. When the shift range is switched from the N range to the R range in this state, the same processing as in steps S220 to S270 described above is performed for the linear solenoid valve (not shown) corresponding to the clutch C3 and the linear solenoid valve corresponding to the brake B2. Should be applied.

  As described above, in the power transmission device 20 of the embodiment, the stall start request is not made, the hydraulic oil is not in the extremely low temperature state, and the linear solenoid valve 54 corresponding to the clutch C1 is temporarily and promptly installed. When the condition for the large opening is not satisfied, the average value of the current flowing through the coil 545 of the electromagnetic unit 544 does not exceed the normal maximum current value Aref and becomes a value corresponding to the output pressure required for the linear solenoid valve 54. The duty ratio and frequency are set as described above, and the transistor 62 is controlled to be switched so that a rectangular wave voltage having the set duty ratio and frequency is applied to the coil 545 of the electromagnetic unit 544. On the other hand, when the above condition is satisfied, such as when a stall start request is made or the shift range is switched from the N range to the D range while the oil temperature T is lower than the reference temperature, the electromagnetic unit 544 A high duty ratio and a low frequency are set and set so that the average value of the current flowing through the coil 545 exceeds the normal maximum current value Aref and becomes a value corresponding to the required output pressure, compared to when the above condition is not satisfied. The transistor 62 is subjected to switching control so that a rectangular wave voltage having a duty ratio and frequency is applied to the coil 545 of the electromagnetic unit 544.

  As described above, when the linear solenoid valve 54 corresponding to the clutch C1 to be engaged when starting the vehicle 10 or switching from the N range to the D range needs to be temporarily and quickly opened, By increasing the linear solenoid valve 54 quickly so that the value of the current flowing through the coil 545 exceeds the normal maximum current value Aref, a larger output pressure can be obtained from the linear solenoid valve 54, or the linear solenoid valve If the working fluid is quickly supplied from 54, it is not necessary to temporarily and quickly increase the linear solenoid valve 54 to a large opening, that is, in accordance with the normal operation, the output gain of the linear solenoid valve 54 (with respect to the current change). Since the degree of change in output pressure can be set low, the linear solenoid bar It is possible to satisfactorily ensure the pressure adjustment precision of the probe 54. Therefore, in the power transmission device 20 of the embodiment, the linear solenoid valve is suppressed while suppressing the decrease in the maximum output pressure of the linear solenoid valve 54 and the inability to quickly supply the working fluid from the linear solenoid valve 54 to the clutch C1. It is possible to ensure the pressure adjustment accuracy of 54.

  In addition, when a condition for temporarily and quickly opening the linear solenoid valve 54 is established, the average value of the current flowing through the coil 545 of the electromagnetic unit 544 exceeds the normal maximum current value Aref and power is supplied to the coil 545. If the state is allowed to become an overcurrent state, it is possible to control a relatively small pressure fluctuation within a wider current range, so that the output gain of the linear solenoid valve 54 can be lowered. It becomes possible to ensure good pressure regulation accuracy of the solenoid valve 54. Further, if the power supply state to the coil 545 of the electromagnetic unit 544 is allowed to become an overcurrent state, the linear solenoid valve 54 is quickly opened to a large opening, thereby further increasing the displacement of the spool 542 and the linear solenoid valve 54. Thus, it is possible to obtain a larger output pressure or to quickly supply hydraulic oil from the linear solenoid valve 54 to the clutch C1. Therefore, in the power transmission device 20 of the embodiment, the linear solenoid valve is suppressed while suppressing the decrease in the maximum output pressure of the linear solenoid valve 54 and the failure of promptly supplying hydraulic oil from the linear solenoid valve 54 to the clutch C1. It becomes possible to ensure the pressure regulation accuracy of 54 favorably.

  Further, when the stall start of the automobile 10 is requested, the transistor is set so that the average value of the current flowing through the coil 545 of the electromagnetic unit 544 exceeds the normal maximum current value Aref and the power supply state to the coil 545 becomes an overcurrent state. If a larger output pressure is obtained from the linear solenoid valve 54 by controlling 62, the high-pressure working fluid required at the stall start can be supplied from the linear solenoid valve 54 to the clutch C1 used at the start. On the other hand, the output gain of the linear solenoid valve 54 is set low in accordance with the normal operation, and the pressure regulation accuracy of the linear solenoid valve 54 can be ensured satisfactorily. In addition, since the frequency with which stall start is performed is relatively low, it is considered that the durability deterioration due to heat generation of the coil 545 of the electromagnetic unit 544 when an overcurrent state occurs can be ignored in practice.

  Further, when switching from the N range to the D range in the cryogenic state, the average value of the current flowing through the coil 545 of the electromagnetic unit 544 exceeds the normal maximum current value Aref, and the power supply state to the coil 545 of the electromagnetic unit 544 is excessive. If the linear solenoid valve 54 is quickly opened to a large degree (fully opened) by controlling the transistor 62 so as to be in a current state, even if the viscosity of the hydraulic oil is in an extremely low temperature state, the N range is changed to the D range. It becomes possible to quickly supply (fill) the working fluid to the clutch C1 to be engaged with the switching to improve the shift response. At this time, since the coil 545 of the linear solenoid valve 54 is in an overcurrent state and the amount of heat generated by the electromagnetic unit 544 increases, the temperature of the hydraulic oil is increased by the heat generated by the coil 545 of the electromagnetic unit 544. It is also possible to promote viscosity and lower the viscosity. Since the output gain of the linear solenoid valve 54 can be set low in accordance with the operation at normal temperature, the pressure regulation accuracy of the linear solenoid valve 54 can be ensured satisfactorily.

  Further, as in the above embodiment, when the condition for temporarily and quickly opening the linear solenoid valve 54 corresponding to the clutch C1 is not satisfied, the current value corresponding to the required output pressure and the current sensor 63 are used. If the duty ratio and frequency are set so that there is no deviation from the detected current value, it is possible to further improve the pressure regulation accuracy of the linear solenoid valve 54 when the above condition is not satisfied. If the duty ratio and frequency are set without using the current value detected by the current sensor 63 when the condition is satisfied, the opening degree of the linear solenoid valve 54 can be quickly increased.

  In the power transmission device 20 of the embodiment, since the electromagnetic portion 544 of the linear solenoid valve 54 is temporarily in an overcurrent state, measures for improving durability against heat generation of the electromagnetic portion 544 are as follows: It is sufficient that it is applied as needed. In addition, when the normal maximum current value Aref itself is secured to a certain extent, the average value of the current flowing through the electromagnetic unit 544 and the like when the condition for temporarily and quickly opening the linear solenoid valve 54 is not satisfied is not established. The duty ratio and frequency are set so that the value becomes a value corresponding to the required output pressure without exceeding a predetermined value less than the normal maximum current value Aref, and the average of the current flowing through the electromagnetic unit 544 and the like when the condition is satisfied A higher duty ratio and a lower frequency may be set as compared to when the required output pressure is equal to or lower than the predetermined pressure so that the value exceeds the predetermined value and becomes a value corresponding to the required output pressure. Furthermore, the automatic transmission 25 included in the power transmission device 20 of the embodiment can provide six forward speeds, but the automatic transmission 25 may have 2 to 5 speeds. It may be more than 7 stages.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above embodiment, the engine is changed while changing the power transmission path from the input shaft 26 connected to the engine 12 mounted on the automobile 10 to the output shaft 27 by switching the engagement state of the clutch C1 and the brake B1. The power transmission device 20 including the automatic transmission 25 that transmits the power from the power source 12 to the output shaft 27 corresponds to a “power transmission device”, and is a normally closed linear that can regulate and output hydraulic oil to the clutch C1. The solenoid valve 54 corresponds to an “electromagnetic valve”, and the transistor 62 provided between the DC power supply 61 and the electromagnetic portion 544 of the linear solenoid valve 54 corresponds to a “switching element”. When the condition for quickly increasing the opening degree is not satisfied, the average value of the current flowing through the electromagnetic unit 544 becomes the common maximum current value Aref. The duty ratio and the frequency are set so as to be a value corresponding to the output pressure required for the linear solenoid valve 54, and a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit 544. When the above condition is satisfied, when the condition is satisfied, the average value of the current flowing through the electromagnetic unit 544 exceeds the normal maximum current value Aref and becomes a value corresponding to the required output pressure. The shift ECU 21 that sets a high duty ratio and a low frequency and controls the switching of the transistor 62 so that a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit 544 is a “control unit”. It corresponds to. A shift unit including a shift lever 95 or the like that allows selection of a desired shift range from a plurality of shift ranges including the D range and the N range corresponds to a “shift unit”. The oil temperature sensor 97 that is provided and detects the temperature of the hydraulic oil corresponds to “temperature acquisition means”. However, the correspondence between the main elements of these embodiments and modifications and the main elements of the invention described in the column of means for solving the problem is described in the column of means for the embodiment to solve the problem. This is an example for specifically describing the best mode for carrying out the invention, and does not limit the elements of the invention described in the column of means for solving the problem. In other words, the examples are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is described in the description of that column. Should be done on the basis.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the power transmission device manufacturing industry.

  DESCRIPTION OF SYMBOLS 10 Motor vehicle, 12 engine, 14 Engine electronic control unit (engine ECU), 16 Brake electronic control unit (brake ECU), 20 Power transmission device, 21 Transmission electronic control unit (transmission ECU), 23 Torque converter, 23a Pump impeller, 23b Turbine runner, 24 Oil pump, 25 Automatic transmission, 26 Input shaft, 27 Output shaft, 28 Gear mechanism, 29 Differential mechanism, 30 Single pinion planetary gear mechanism, 31, 36a, 36b Sun gear, 32, 37 ring gear, 33 pinion gear, 34, 39 carrier, 35 Ravigneaux planetary gear mechanism, 38a short pinion gear, 38b long pinion gear, 40 strainer, 45 oil pan, 50 hydraulic control unit, 51 linear solenoid valve, 2 Regulator valve, 53 Manual valve, 54, 55 Linear solenoid valve, 60 Drive circuit, 61 DC power supply, 62 Transistor, 63 Current sensor, 91 Accel pedal, 92 Accel pedal position sensor, 93 Brake pedal, 94 Master cylinder pressure sensor, 95 shift lever, 96 shift range sensor, 97 oil temperature sensor, 99 vehicle speed sensor, 541,551 sleeve, 542,552 spool, 543,553 spring, 544,554 electromagnetic part, B1, B2 brake, C1, C2, C3 clutch , F1 one-way clutch.

Claims (5)

The power from the power generation source is changed while changing the power transmission path from the input shaft connected to the power generation source mounted on the vehicle to the output shaft by switching the engagement state of at least one friction engagement element. A power transmission device for transmitting to an output shaft,
A solenoid valve capable of regulating and outputting a working fluid to the friction engagement element;
A switching element connected to the electromagnetic part of the solenoid valve;
When the predetermined condition for temporarily and quickly opening the solenoid valve is not satisfied, the average value of the current flowing through the electromagnetic unit does not exceed the predetermined current value according to the output pressure required for the solenoid valve. The switching ratio of the switching element is controlled so that a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit, and the predetermined condition is satisfied. Sometimes, a higher duty ratio and lower frequency are set than when the predetermined condition is not satisfied so that an average value of the current flowing through the electromagnetic unit exceeds the predetermined current value and becomes a value corresponding to the required output pressure. And switching control of the switching element so that a rectangular wave voltage having the duty ratio and the frequency is applied to the electromagnetic unit. And control means,
Equipped with a,
The predetermined current value is a normal maximum current value allowed for the electromagnetic part of the electromagnetic valve,
Wherein, when the predetermined condition is satisfied, the power transmission powered state is to set the high duty ratio and a low frequency compared to the time of non-satisfaction of the predetermined condition such that the overcurrent state to the solenoid portion apparatus. The power transmission device according to claim 1 ,
The power transmission device that is satisfied when the predetermined condition is satisfied when a stall start of the vehicle is requested and is not satisfied when the stalled state ends. In the power transmission device according to claim 1 or 2,
A shift unit that allows selection of an arbitrary shift range from a plurality of shift ranges including at least a traveling range and a neutral range;
Temperature acquisition means for acquiring the temperature of the working fluid;
The friction engagement element is a fluid pressure clutch to be engaged when the shift range is switched from the neutral range to the travel range;
The predetermined condition is a power transmission device that is established when the shift range is switched from the neutral range to the travel range in a state where the temperature acquired by the temperature acquisition means is equal to or lower than a predetermined temperature. In the power transmission device according to claim 3 ,
The power transmission device in which the predetermined condition is not established when a predetermined time has elapsed after switching from the neutral range to the travel range. In the power transmission device according to any one of claims 1 to 4 ,
A current sensor for obtaining a value of a current flowing through the electromagnetic unit;
The control means sets the duty ratio and the frequency so that there is no deviation between the current value corresponding to the required output pressure and the current value detected by the current sensor when the predetermined condition is not satisfied, A power transmission device that sets the duty ratio and the frequency without using a current value detected by the current sensor when a predetermined condition is satisfied.

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