JP2015075162A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a gear change device which can prevent the simultaneous engagement of friction engagement elements which are undesirable in the simultaneous engagement while suppressing a cost increase and the lowering of the switch responsiveness of a gear change stage and the like.SOLUTION: A control device of a gear change device which gear-changes and outputs inputted power, and can change a gear change ratio comprises: a plurality of friction engagement elements which are driven by hydraulic pressure; actuators which are arranged at a plurality of the friction engagement elements, and control the hydraulic pressure which is supplied to a plurality of the friction engagement elements; and a control part which selectively drives the actuators, and controls the gear change ratio by changing engagement patterns of a plurality of the friction engagement elements. When a prescribed gear change ratio is constituted by the control part, a passage in which a drive command for driving the actuator corresponding to at least one of the friction engagement elements which are not engaged in the constitution of the prescribed gear change is transmitted is blocked.

Description

  The present invention relates to a transmission control device.

  2. Description of the Related Art Conventionally, there are known transmissions that change a gear ratio (shift speed) by engaging / disengaging a plurality of hydraulic friction engagement elements (clutch, brake, etc.). In the transmission, when the hydraulic pressure is supplied to one friction engagement element so that the friction engagement elements which are not desirable when simultaneously engaged are not simultaneously engaged due to malfunction, A technique for blocking a hydraulic pressure supply path to an element has been proposed (for example, Patent Document 1).

JP 2012-207721 A

  However, in order to cut off the hydraulic pressure supply path, it is necessary to provide a fail-safe valve, which may cause a problem such as an increase in cost.

  Further, when switching the gear position, the fail-safe valve needs to be switched, which may cause a decrease in responsiveness.

  Therefore, in view of the above problems, it is possible to prevent simultaneous engagement of frictional engagement elements that are undesirable when engaged simultaneously, while suppressing an increase in cost, a decrease in responsiveness of switching of gears, and the like. An object of the present invention is to provide a transmission control device.

In order to achieve the above object, in one embodiment, the control device comprises:
A transmission control device capable of shifting and outputting input power and changing a gear ratio,
A plurality of friction engagement elements driven by hydraulic pressure;
An actuator that is provided for each of the plurality of friction engagement elements and controls the hydraulic pressure supplied to each of the plurality of friction engagement elements;
A controller that selectively drives each of the actuators and controls the speed ratio by changing an engagement pattern of the plurality of friction engagement elements;
When a predetermined gear ratio is configured by the control unit, a path through which a drive command for driving an actuator corresponding to at least one of the friction engagement elements not engaged in the configuration of the predetermined gear ratio is interrupted is cut off. It is characterized by doing.

  According to the present embodiment, it is possible to prevent simultaneous engagement of frictional engagement elements that are undesirable when engaged at the same time, while suppressing an increase in cost, a decrease in responsiveness to switching between gears, and the like. A transmission control device can be provided.

It is a schematic block diagram of the vehicle containing the control apparatus (TM-ECU) of an automatic transmission. FIG. 2 is a schematic configuration diagram of an automatic transmission and an operation table showing a correspondence relationship between each shift stage and a clutch and a brake. It is a block diagram which shows the relationship between TM-ECU which concerns on 1st Embodiment, and the hydraulic pressure supply path | route to the clutch and brake in an automatic transmission. It is a figure explaining an example of the interruption | blocking method of the drive command path | route to the solenoid valve which controls the hydraulic pressure supplied to the clutch or brake in the automatic transmission by TM-ECU which concerns on 1st Embodiment. It is a block diagram which shows the relationship between TM-ECU which concerns on 2nd Embodiment, and the hydraulic pressure supply path | route to the clutch and brake in an automatic transmission. It is a figure explaining an example of the interruption | blocking method of the drive command path | route to the solenoid valve which controls the hydraulic pressure supplied to the clutch or brake in the automatic transmission by TM-ECU which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of a vehicle including an automatic transmission control device (TM-ECU) according to the present embodiment.

  The vehicle 1 is allowed to travel when the power of the engine 10 is changed (accelerated / decelerated) by the automatic transmission 20 and transmitted to the drive wheels DW via the drive shaft DS. The vehicle 1 may be an electric vehicle having an electric motor as one of the drive sources, and may be configured such that the power of the electric motor is shifted by the automatic transmission 20 and transmitted to the drive wheels DW.

  The vehicle 1 also includes an engine ECU 30, a transmission ECU (hereinafter referred to as TM-ECU) 40, and the like.

  The engine ECU 30 and the TM-ECU 40 are both a ROM that stores a control program, a CPU that loads a predetermined control program from the ROM, performs arithmetic processing, a readable / writable RAM that stores arithmetic results, a timer, a counter, an input / output Including interfaces. Various control processes are executed by executing each control program on the CPU. Further, the engine ECU 30 and the TM-ECU 40 are configured to be able to communicate with various sensors in the vehicle 1, other ECUs, and the like through an in-vehicle LAN such as a CAN (Controller Area Network) or a direct line, or receive various signals. Can be sent.

  The engine ECU 30 is an electronic control unit that controls the engine 10. The engine ECU 30 determines the fuel injector (fuel injection timing, amount, etc.), spark plug (ignition timing, etc.), spark plug (ignition timing, etc.), intake / exhaust valve (opening / closing timing, etc.) of the engine 10 based on the accelerator opening, vehicle speed, crank angle, engine speed, etc. ) Etc. Note that the engine ECU 30 may acquire the accelerator opening by receiving an output signal of an accelerator opening sensor (not shown) provided in an accelerator pedal (not shown). The engine ECU 30 may acquire the vehicle speed of the vehicle 1 by receiving an output signal from a vehicle speed sensor (not shown). Further, the engine ECU 30 may acquire the crank angle and the engine speed by receiving an output signal of a crank angle sensor (not shown) in the engine 10.

  The TM-ECU 40 is an electronic control unit that controls the automatic transmission 20. The TM-ECU 40 performs shift speed switching control based on a shift range (for example, parking, reverse, neutral, drive, etc.), vehicle speed, and the like. Further, the TM-ECU 40 may perform shift speed switching control based on the driver's operation when the driver's manual shift operation is possible. Specifically, control is performed to switch engagement patterns of clutches C1 and C2 and brakes B1 and B2, which are hydraulic friction engagement elements (hereinafter simply referred to as friction engagement elements) in the automatic transmission 20 described later. . The TM-ECU 40 may acquire the shift range by receiving an output signal of a shift range sensor (not shown) that detects the operation position of the shift lever. The speed change operation by the driver of the vehicle 1 may be an operation other than a lever, for example, an operation using a button or the like. In this case, the shift range may be acquired by receiving a signal corresponding to the button operation. Further, the TM-ECU 40 may acquire the vehicle speed of the vehicle 1 by receiving an output signal of a vehicle speed sensor (not shown).

  Next, an outline of the speed change mechanism of the automatic transmission 20 will be described.

  FIG. 2 is a schematic configuration diagram of the automatic transmission 20 and an operation table showing the correspondence between each shift stage, the clutch, and the brake. FIG. 2A is a schematic configuration diagram of the automatic transmission 20. FIG. 2B is an operation table showing a correspondence relationship between each shift stage of the automatic transmission 20 and the clutches and brakes that are friction engagement elements.

  The automatic transmission 20 is a transmission capable of shifting and outputting input power and changing the gear ratio to a plurality of stages. Referring to FIG. 2A, the automatic transmission 20 includes a planetary gear mechanism 22, clutches C1 and C2, brakes B1 and B2, and a one-way clutch FW for changing a power transmission path from input to output. Including. Although not shown in the figure, the input shaft 21 is coupled to a fluid transmission device such as a torque converter, and the power of the engine 10 is transmitted by the fluid transmission device. Similarly, although not shown, a differential mechanism is coupled to the output shaft 25, and power is output to the left and right drive shafts DS via the differential mechanism.

  The planetary gear mechanism 22 includes two planetary gear trains 23 and 24.

  The planetary gear train 23 includes a sun gear 23s that is an external gear, a ring gear 23r that is an internal gear, a sun gear 23s, and a plurality of planetary gears 23p that mesh with the ring gear 23r. The sun gear 23s is coaxially coupled to a sun gear 24s of a planetary gear train 24, which will be described later, and is configured to be coupled to the transmission case 26 via the brake B1. The ring gear 23r is configured to be connectable to the input shaft 21 via a clutch C1 described later. The planetary gear 23p is coupled to the output shaft 25 via the carrier 23c.

  The planetary gear train 24 includes a sun gear 24s that is an external gear, a ring gear 24r that is an internal gear, a sun gear 24s, and a plurality of planetary gears 24p that mesh with the ring gear 24r. The sun gear 24s is coaxially coupled to the sun gear 23s of the planetary gear train 23, and is configured to be coupled to the transmission case 26 via the brake B1. The ring gear 24r is coupled to the output shaft 25. The planetary gear 24p is coupled to a later-described brake B2 and one-way clutch FW via a carrier 24c, and is configured to be coupled to the transmission case 26 via the brake B2 and one-way clutch FW.

  The clutch C1 is a hydraulic clutch capable of fastening the input shaft 21 and the ring gear 23r of the planetary gear mechanism 22 and releasing the fastening of both.

  The clutch C2 is a hydraulic clutch that can fasten the input shaft 21 and the sun gears 23s and 24s of the planetary gear mechanism 22 and can release the fastening of both.

  The brake B <b> 1 is a hydraulic clutch that can fix the sun gears 23 s and 24 s of the planetary gear mechanism 22 to the transmission case 26, and can release the fixation to the transmission case 26.

  The brake B2 is a hydraulic clutch capable of fixing the planetary gear 24p of the planetary gear mechanism 22 to the transmission case 26 and releasing the fixation of the planetary gear 24p to the transmission case 26.

  As will be described later, the clutches C1, C2 and the brakes B1, B2 are driven by the hydraulic pressure supplied from the oil pump 27, and the TM-ECU 40 transmits the hydraulic pressure to the clutches C1, C2, brakes B1, and B2. Controls supply and switches gears. In the following, the above-described “engagement” of the clutches C1 and C2 and “fixation” of the brakes B1 and B2 may be collectively expressed as “engagement” of the friction engagement elements.

  The one-way clutch FW is a clutch capable of restricting transmission of rotational torque in only one direction, and acts as a reaction force element when driving the first forward speed described later.

  In addition, referring to FIG. 2B, the first forward speed is configured by driving the clutch C1 and the brake B2. Note that the brake B2 acts only when the engine is braked (accelerator is off). The second forward speed is configured by driving the clutch C1 and the brake B1. Further, the third forward speed is configured by driving the clutch C1 and the clutch C2. Further, the reverse movement is configured by driving the clutch C2 and the brake B2.

  As described above, the automatic transmission 20 constitutes the first to third forward speeds and the reverse speed stages each having a predetermined speed ratio, and the clutch C1, C2 and the brakes B1, B2 are illustrated in the operation table. By providing the above, three forward speeds and one reverse speed are provided.

  Next, the shift control of the automatic transmission 20 by the TM-ECU 40 according to the present embodiment will be described.

  FIG. 3 is a block diagram showing the relationship between the TM-ECU 40 according to the present embodiment and the hydraulic pressure supply paths to the clutches C1 and C2 and the brakes B1 and B2 in the automatic transmission 20. In the drawing, a thick solid line represents a hydraulic pressure supply line, a thin solid line represents a power supply line, and a dotted line represents a control command line.

  Automatic transmission 20 includes an oil pump 27 and solenoid valves SL1, SL2, SL3, and SL4.

  The oil pump 27 is a hydraulic pressure supply unit that is driven by power extracted from the output shaft of the engine 10. The oil pump 27 may be any pump that can pump hydraulic oil in the transmission case 26, such as an internal gear pump, an external gear pump, or a (centrifugally movable) vane pump. The oil pump 27 is configured to suck hydraulic oil in the transmission case 26 from an oil pan (not shown) of the automatic transmission 20 and supply hydraulic pressure to the clutches C1, C2, brakes B1, B2, and the like. Although not shown for simplicity, a pressure regulating valve or the like that adjusts the hydraulic pressure is provided between the oil pump 27 and the solenoid valves SL1 to SL4, and the hydraulic pressure adjusted by the pressure regulating valve or the like controls SL1 to SL4. To the clutches C1 and C2 and the brakes B1 and B2.

  Solenoid valves SL1, SL2, SL3, and SL4 are electromagnetic proportional valves that control the hydraulic pressure supplied to clutches C1, C2, brakes B1, and B2, respectively. Each solenoid valve SL1 to SL4 can linearly adjust the hydraulic pressure supplied from the oil pump 27 according to the current flowing through the solenoid.

  The TM-ECU 40 includes drive transistors SW11, SW12, SW13, and SW14, and a microcomputer 41.

  The drive transistors SW11, SW12, SW13, and SW14 are switching elements that supply power to the solenoid valves SL1, SL2, SL3, and SL4, respectively. When a voltage is applied to the gate terminals of the drive transistors SW11 to SW14, the battery 50 is electrically connected to the solenoid valves SL1 to SL4, and power is supplied from the battery 50 to the solenoid valves SL1 to SL4. Specifically, in order to control the current flowing through the solenoids of the solenoid valves SL1 to SL4, each drive transistor (gate terminal thereof) has an on / off drive command signal (Hi signal) with a duty ratio corresponding to the current flowing through the solenoid. And the Lo signal are repeated). For example, the voltage of the battery 50 is applied to the solenoid of the solenoid valve SL2 when the drive transistor SW12 is on, and the current flowing in proportion to the voltage applied to the solenoid increases. Further, since the solenoid of the solenoid valve SL2 has a reactance component and has a characteristic of continuing to flow current, even when the drive transistor SW12 is off, the current continues to flow while decreasing the current value. Therefore, by driving the drive transistor SW12 on and off, the current continues to flow through the solenoid of the solenoid valve SL2 while the current repeatedly increases and decreases. Supply hydraulic pressure is adjusted.

  The microcomputer 41 performs shift stage switching control, and specifically transmits a drive command signal to the drive transistors SW11 to SW14. In order to drive the element corresponding to the gear position from among the clutches C1, C2 and the brakes B1, B2, the microcomputer 41 transmits a drive command signal to the drive transistor corresponding to the element. For example, when shifting to the first forward speed, the clutch C1 and the brake B2 are driven, so the microcomputer 41 outputs a drive command signal to the drive transistors SW11 and SW14. At this time, the microcomputer 41 calculates a current value to be supplied to the solenoids SL1 and SL4 for adjusting the hydraulic pressure supplied to the clutch C1 and the brake B2, and drives an on / off drive command signal with a duty ratio corresponding to the current value. Output to the transistors SW11 and SW14.

  TM-ECU 40 includes cutoff transistors SW22, SW23, and SW24.

  The cutoff transistors SW22, SW23, and SW24 are switching elements for blocking the drive command path 42 from the microcomputer 41 to the drive transistors SW12, SW13, and SW14, respectively. Referring to FIG. 2B described above, there is no engagement pattern in which the clutch C2 and the brake B1 are simultaneously engaged. Further, there is no engagement pattern in which the brake B1 and the brake B2 are simultaneously engaged. Therefore, the drive command path 42-3 from the microcomputer 41 to the drive transistor SW13 is blocked by the cutoff transistor SW23 according to the drive command signal to the drive transistor SW12 output from the microcomputer 41. Further, in response to the drive command signal output from the microcomputer 41 to the drive transistor SW13, the cutoff transistor SW22 cuts off the drive command path 42-2 from the microcomputer 41 to the drive transistor SW12, and the cutoff transistor SW24 sends the drive transistor from the microcomputer 41 to the drive transistor. The drive command path 42-4 to SW14 is cut off. Further, the drive command path 42-3 from the microcomputer 41 to the drive transistor SW13 is blocked by the cutoff transistor SW23 in accordance with the drive command signal to the drive transistor SW14 output from the microcomputer 41. As a result, the friction engagement elements that are not simultaneously engaged at any of the first to third forward speeds or the reverse speed are erroneously simultaneously engaged by an erroneous drive command signal from the microcomputer 41. Therefore, undesirable behaviors such as gear lock of the automatic transmission 20 can be prevented.

  Here, specific configuration examples and operations of the cutoff transistors SW22, SW23, and SW24 will be described.

  FIG. 4 shows an example of a drive command path blocking method for driving a solenoid valve that controls the hydraulic pressure supplied to the clutches C1 and C2 or the brakes B1 and B2 in the automatic transmission 20 by the TM-ECU 40 according to the present embodiment. FIG. Hereinafter, a method for blocking the drive command path 42-2 from the microcomputer 41 to the drive transistor SW12 by the cutoff transistor SW22 according to the drive command signal to the drive transistor SW13 output from the microcomputer 41 will be described. Similarly, a method of blocking the drive command path 42-3 from the microcomputer 41 to the drive transistor SW13 by the cutoff transistor SW23 according to the drive command signal to the drive transistor SW12 output from the microcomputer 41 will be described. Note that the method (circuit configuration) for blocking each drive command path 42 is the same, and the other description is omitted.

  Referring to FIG. 4, the microcomputer 41 and the gate terminals of the drive transistors SW12 and SW13 are connected, and these connection lines become drive command paths 42-2 and 42-3 from the microcomputer 41 to the drive transistors SW12 and SW13. The collector terminal of the cutoff transistor SW22 is connected by branching from an intermediate connection point P2 of the drive command path 42-2 that connects the microcomputer 41 and the gate terminal of the drive transistor SW12. The emitter terminal of the cutoff transistor SW22 is grounded. Similarly, the collector terminal of the cutoff transistor SW23 is connected by branching from the intermediate connection point P3 of the drive command path 42-3 connecting the microcomputer 41 and the gate terminal of the drive transistor SW13. The emitter terminal of the cutoff transistor SW23 is grounded.

  The collector terminal of the drive transistor SW12 is connected to the battery 50, and the emitter terminal is connected to the solenoid of the solenoid valve SL2. Similarly, the collector terminal of the drive transistor SW13 is connected to the battery 50, and the emitter terminal is connected to the solenoid of the solenoid valve SL3. When a voltage is applied to the gate terminal of the drive transistor SW12, the collector-emitter of the drive transistor SW12 becomes conductive, the voltage of the battery 50 is applied from the battery 50 to the solenoid valve SL2, and a current flows through the solenoid. Similarly, when a voltage is applied to the gate terminal of the drive transistor SW13, the collector-emitter of the drive transistor SW13 becomes conductive, the voltage of the battery 50 is applied from the battery 50 to the solenoid valve SL3, and a current flows through the solenoid.

  A detection resistor R2 is provided on the ground side of the solenoid valve SL2. A connection line branched from the intermediate connection point P2R between the detection resistor R2 and the solenoid valve SL2 is connected to the gate terminal of the cutoff transistor SW23. Similarly, a detection resistor R3 is provided on the ground side of the solenoid valve SL3. A connection line branched from a connection point P3R between the detection resistors R3 and SL3 is connected to the gate terminal of the cutoff transistor SW22.

  Here, as described above, when driving the clutch C2, the microcomputer 41 outputs an on / off signal with a duty ratio corresponding to the current flowing through the solenoid of the solenoid valve SL2 as a drive command signal, and drives the drive transistor SW12 on and off. By driving the drive transistor SW12 on and off, current continues to flow through the solenoid of the solenoid valve SL2 while the current repeatedly increases and decreases, and the hydraulic pressure supplied from the solenoid valve SL2 to the clutch C2 by the average current value of the increased and decreased current. Is adjusted. Therefore, when a drive command signal is output from the microcomputer 41 to the drive transistor SW12, a voltage corresponding to the current flowing through the solenoid of the solenoid valve SL2 is generated at the connection point P2R. The voltage generated at the connection point P2R is applied to the gate terminal of the cutoff transistor SW23, and the collector terminal and the emitter terminal of the cutoff transistor SW23 are conducted. As a result, the connection point P3 is grounded and is always 0V, so that the microcomputer 41 cannot output an ON signal (Hi signal) to the drive transistor SW13, and as a result, the drive command path 42-3 is blocked. . That is, using the current flowing through the solenoid valve SL2 according to the drive command signal for driving the solenoid valve SL2, the cutoff transistor SW23 can be turned on and the drive command path 42-3 can be shut off.

  Similarly, when driving the brake B1, when a drive command signal is output from the microcomputer 41 to the drive transistor SW13, a voltage corresponding to the current flowing through the solenoid of the solenoid valve SL3 is generated at the connection point P3R. To do. The voltage generated at the connection point P3R is applied to the gate terminal of the cutoff transistor SW22, and the collector terminal and the emitter terminal of the cutoff transistor SW22 are conducted. As a result, the connection point P2 is grounded and always becomes 0V, so that the microcomputer 41 cannot output an ON signal (Hi signal) to the drive transistor SW12, and as a result, the drive command path 42-2 is blocked. . That is, using the current flowing through the solenoid valve SL3 in response to the drive command signal for driving the solenoid valve SL3, the cutoff transistor SW22 can be turned on and the drive command path 42-2 can be shut off.

  Note that a voltage corresponding to the current flowing through the solenoid of the solenoid valve SL4 in response to a drive command signal from the microcomputer 41 to the drive transistor SW14 is also applied to the gate terminal of the cutoff transistor SW23. Therefore, although omitted in FIG. 4 for simplicity, a logic circuit (OR circuit) may be provided between the gate terminal of the cutoff transistor SW23 and the connection point P2R. Then, when any one of a voltage corresponding to the current flowing through the solenoid of the solenoid valve SL2 and a voltage corresponding to the current flowing through the solenoid of the solenoid valve SL4 is input, the cutoff transistor SW23 may be turned on. .

  As described above, the TM-ECU 40 according to the present embodiment, as a fail-safe function, drives one friction engagement element with respect to friction engagement elements that are not simultaneously engaged in any of the shift speeds. Accordingly, the drive command path for driving the other friction engagement element is interrupted. Thereby, an undesirable behavior such as a gear lock of the automatic transmission 20 can be prevented.

  Further, since the drive command path for driving the frictional engagement element which is not preferable when engaged by the electronic circuit is cut off, the shift stage switching responsiveness is improved as compared with a method using a hydraulic circuit (for example, the above fail-safe valve). The decrease can be suppressed.

  Further, since the drive command path for driving the frictional engagement element which is not preferable when engaged by the electronic circuit configuration is cut off regardless of the calculation processing by the microcomputer or the like, the reliability of the failsafe function can be improved.

  Moreover, since the fail-safe function can be realized only by adding the cutoff transistors SW22 to SW24 and the like, an increase in cost can be suppressed.

  Further, when the shut-off transistors SW22 to SW24 etc. fail, there are cases where (1) the drive command path that should not be shut off is shut off and (2) the drive command path that should be shut off is not shut off. However, in the case of (1), it is possible to detect the behavior of the automatic transmission 20, and since the drive command path is cut off excessively, an undesirable behavior such as gear lock does not occur in the automatic transmission 20. . In the case of (2), a test drive command output is output from the microcomputer 41 to the drive command path 42 that is blocked by the cutoff transistors SW22 to SW24 without affecting the driving of the automatic transmission 20 such as when the vehicle is stopped. It is possible to detect a failure safely. That is, a potential failure of the failsafe function can be detected safely.

  In the present embodiment, when one frictional engagement element is driven with respect to frictional engagement elements that are not simultaneously engaged in any of the shift speeds, a drive command for driving the other frictional engagement element. Although the path is cut off, the drive command path that drives all or a part of the friction engagement elements that are not engaged when a predetermined gear ratio is configured may be cut off. For example, in the case of the second forward speed, the clutch C1 and the brake B1 are engaged, so that the cutoff transistors SW22 and SW24 are turned on according to the drive command signal to the drive transistors SW11 and SW13, and the drive command path 42-2 42-4 may be shut off. As a result, the clutch C2 and the brake B2 are not engaged due to malfunction of the microcomputer 41 or the like. Specifically, when a voltage (voltage by a detection resistor or the like) corresponding to a current flowing through each solenoid of the solenoid valves SL1 and SL3 is input according to a drive command signal to the drive transistors SW11 and SW13, the cutoff transistor A logic circuit that outputs a cutoff command signal to SW22 and SW24 may be configured. The same applies to the other gear positions (first forward, third, reverse). In this case, the drive command path 42-1 may be provided with a cutoff transistor SW21 so that the drive command path 42-1 can also be cut off.

[Second Embodiment]
Next, a second embodiment will be described.

  The transmission control device (TM-ECU) according to the present embodiment sets a monitoring microcomputer for blocking the drive command path for the friction engagement element, in addition to the microcomputer for controlling the engagement / disengagement of the friction engagement element. In this respect, it is mainly different from the first embodiment. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and different portions will be mainly described.

  Since the schematic configuration of the vehicle including the automatic transmission control device (TM-ECU) according to the present embodiment is the same as that of FIG. 1 according to the first embodiment, description thereof is omitted.

  Further, the schematic configuration of the automatic transmission 20 according to the present embodiment and the correspondence relationship between the respective shift speeds and the clutches and brakes are the same as those in FIG. 2 according to the first embodiment, and thus the description thereof is omitted.

  Next, the shift control of the automatic transmission 20 by the TM-ECU 40 according to the present embodiment will be described.

  FIG. 5 is a block diagram showing the relationship between the TM-ECU 40 according to the present embodiment and the hydraulic pressure supply paths to the clutches C1 and C2 and the brakes B1 and B2 in the automatic transmission 20. In the drawing, a thick solid line represents a hydraulic pressure supply line, a thin solid line represents a power supply line, and a dotted line represents a control command line. In the following, description of the same parts as those in FIG. 3 according to the first embodiment will be omitted, and description will be made focusing on the parts specific to the present embodiment.

  Referring to FIG. 5, TM-ECU 40 includes monitoring microcomputer 44 in addition to microcomputer 41.

  The monitoring microcomputer 44 can shut off each drive command path 42 by outputting a shutoff command signal to the shutoff transistors SW21 to SW24 (the gate terminals thereof). For example, when shifting to the second forward speed under the control of the microcomputer 41, the monitoring microcomputer 44 acquires information on the gear position from the microcomputer 41, and friction engagement elements (clutch C2 and brake B2) that are not engaged at the second forward speed. A cutoff command signal is output to the cutoff transistors SW22 and SW24 corresponding to. As a result, the drive command paths 42-2 and 42-4 are blocked. For other shift speeds (first forward speed, third speed, and reverse speed), a cutoff command signal is output to a cutoff transistor corresponding to a friction engagement element that is not engaged in the corresponding shift stage. As a result, when a predetermined gear ratio is configured, the drive command path for driving the friction engagement elements that are not engaged can be blocked. For this reason, even if an erroneous drive command signal is output due to a malfunction of the microcomputer 41 or the like, the drive command path is blocked, so that undesirable behavior such as gear locking of the automatic transmission 20 can be prevented. It becomes possible.

  Here, a specific configuration example and operation of the monitoring microcomputer 44 and the cutoff transistors SW21 to SW24 will be described.

  FIG. 6 shows an example of a drive command path blocking method for driving a solenoid valve that controls the hydraulic pressure supplied to the clutches C1 and C2 or the brakes B1 and B2 in the automatic transmission 20 by the TM-ECU 40 according to the present embodiment. FIG. Hereinafter, a method for blocking the drive command path 42-2 from the microcomputer 41 to the drive transistor SW12 by the cutoff transistor SW22 according to the cutoff command signal from the monitoring microcomputer 44 will be described. The method (circuit configuration) for blocking each drive command path 42 is the same, and thus the description of the method for blocking the other drive command paths 42-1, 42-3, 42-4 is omitted.

  Referring to FIG. 6, as in the first embodiment, the microcomputer 41 and the gate terminal of the drive transistor SW12 are connected, and this connection line becomes a drive command path 42-2 from the microcomputer 41 to the drive transistor SW12. Further, the collector terminal of the cutoff transistor SW22 is branched from the connection point P2 in the middle of the drive command path 42-2 connecting the microcomputer 41 and the gate terminal of the drive transistor SW12. The emitter terminal of the cutoff transistor SW22 is grounded.

  As in the first embodiment, the collector terminal of the drive transistor SW12 is connected to the battery 50, and the emitter terminal is connected to the solenoid of the solenoid valve SL2. When a voltage is applied to the gate terminal of the drive transistor SW12, the collector-emitter of the drive transistor SW12 becomes conductive, the voltage of the battery 50 is applied from the battery 50 to the solenoid valve SL2, and a current flows through the solenoid.

  The monitoring microcomputer 44 is connected to the gate terminal of the cutoff transistor SW22. When a cutoff command signal is output from the monitoring microcomputer 44 and a voltage is applied to the cutoff transistor SW22, the collector-emitter of the cutoff transistor SW22 is conducted. As a result, the connection point P2 is grounded and is always 0 V, so that the microcomputer 41 cannot output an ON signal (Hi signal) to the drive transistor SW12, and as a result, the drive command path 42-2 is blocked. . By the same operation, the monitoring microcomputer 44 can output a cutoff command signal to each gate terminal of the cutoff transistors SW21, SW23, SW24, and can shut off the drive command paths 42-1, 42-3, 42-4.

  As described above, the TM-ECU 40 according to the present embodiment cuts off the drive command path for driving the friction engagement element that is not engaged when the predetermined gear ratio is configured as the fail-safe function. Thereby, an undesirable behavior such as a gear lock of the automatic transmission 20 can be prevented.

  Further, since the drive command path for driving the frictional engagement element which is not desirable when engaged by the shutoff command signal from the monitoring microcomputer 44 is shut off, the speed change is performed as compared with a method using a hydraulic circuit (for example, the above-described failsafe valve). It is possible to suppress a reduction in stage switching response.

  Further, since the drive command path for driving the frictional engagement element which is not preferable when the monitoring microcomputer 44 is different from the microcomputer 41 which performs the shift control of the automatic transmission 20 is cut off, the reliability of the failsafe function is improved. It becomes possible to raise.

  Further, since the fail-safe function can be realized only by adding the monitoring microcomputer 44, the cutoff transistors SW21 to SW24, etc., for example, the increase in cost can be suppressed as compared with the case where a fail-safe valve is added to the hydraulic circuit. Is possible.

  Further, when the monitoring microcomputer 44, the cutoff transistors SW21 to SW24, etc. fail, there are cases where (1) the drive command path that should not be cut off is cut off and (2) the drive command path that should be cut off is not cut off. However, in the case of (1), it is possible to detect the behavior of the automatic transmission 20, and since the drive command path is cut off excessively, an undesirable behavior such as gear lock does not occur in the automatic transmission 20. . In the case of (2), the drive command path 42 that is blocked by the cutoff transistors SW21 to SW24 based on the cutoff command from the monitoring microcomputer 44 in a state that does not affect the driving of the automatic transmission 20 such as when the vehicle is stopped, It is possible to detect a failure safely by outputting a test drive command from the microcomputer 41. That is, a potential failure of the failsafe function can be detected safely.

  In the present embodiment, all of the drive command paths for driving the friction engagement elements that are not engaged when a predetermined speed ratio is configured are cut off. However, when a predetermined speed ratio is configured, A part (at least one) of the drive command path that drives the frictional engagement elements that do not match may be blocked. For example, among the friction engagement elements that are not engaged when a predetermined gear ratio is configured, the drive command path that drives the friction engagement elements that cause the automatic transmission 20 to perform undesirable behavior when simultaneously engaged is selectively cut off. You can do it. Similarly to the first embodiment, when one frictional engagement element is driven with respect to frictional engagement elements that are not simultaneously engaged at any of the shift speeds, the other frictional engagement element is driven. The drive command path to be performed may be blocked.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

  For example, in each of the above-described embodiments, the automatic transmission 20 is a transmission with three forward speeds and one reverse speed. However, the automatic transmission 20 may be a transmission with more gear speeds or fewer gear speeds. It may be a transmission.

  Further, in each of the above-described embodiments, the automatic transmission 20 has the engine 10 as a power source separately. However, the automatic transmission 20 may have a power source such as a drive motor in the transmission.

1 Vehicle 10 Engine 20 Automatic Transmission 30 Engine ECU
40 Transmission ECU
41 Microcomputer (control unit)
42 Drive Command Path 42-1, 42-2, 42-3, 42-4 Drive Command Path 44 Monitoring Microcomputer (Other Control Unit)
50 Battery B1, B2 Brake (friction engagement element)
C1, C2 clutch (friction engagement element)
FW One-way clutch SL1 to SL4 Solenoid valve (actuator)
SW11 to SW14 drive transistor SW21 to SW24 cutoff transistor

Claims (5)

A transmission control device capable of shifting and outputting input power and changing a gear ratio,
A plurality of friction engagement elements driven by hydraulic pressure;
An actuator that is provided for each of the plurality of friction engagement elements and controls the hydraulic pressure supplied to each of the plurality of friction engagement elements;
A controller that selectively drives each of the actuators and controls the speed ratio by changing an engagement pattern of the plurality of friction engagement elements;
When a predetermined gear ratio is configured by the control unit, a path through which a drive command for driving an actuator corresponding to at least one of the friction engagement elements not engaged in the configuration of the predetermined gear ratio is interrupted is cut off. It is characterized by
Control device. Said at least one is
One of the friction engagement elements engaged in the configuration of the predetermined gear ratio is a friction engagement element that does not simultaneously engage in any of the engagement patterns.
The control device according to claim 1. Provided with another control unit different from the control unit,
The other control unit is
When the predetermined gear ratio is configured by the control unit, the route is blocked.
The control device according to claim 1 or 2. The path is blocked in response to a drive command for driving an actuator corresponding to a friction engagement element engaged in the configuration of the predetermined speed ratio.
The control device according to claim 1 or 2. The actuator is a solenoid valve;
The path is blocked using a current flowing through a solenoid in the solenoid valve in response to a drive command for driving a solenoid valve corresponding to a friction engagement element to be engaged in the configuration of the predetermined gear ratio. To
The control device according to claim 4.

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