JP4978605B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission mounted on a vehicle or the like, and more particularly to a control device for an automatic transmission that can accurately detect a failure during a downshift.

  Generally, in a multi-stage automatic transmission mounted on a vehicle or the like, a plurality of friction engagement elements (clutches and brakes) are engaged in accordance with the shift speed in order to form a transmission path of a transmission gear mechanism. . However, if hydraulic pressure is output to the hydraulic servo of the frictional engagement element that should have been released due to, for example, a failure of the linear solenoid valve (disconnection, valve stick, etc.), the frictional engagement element that is normally engaged In addition, there is a possibility that the frictional engagement element that should have been released is engaged.

  Conventionally, in order to prevent such simultaneous engagement, when the engagement pressure of the friction engagement element engaged at normal time is input, the hydraulic pressure (its original pressure) of the other friction engagement elements is cut off. , So-called cutoff valves are provided in accordance with the combination of friction engagement elements that are engaged at each gear stage, thereby preventing simultaneous engagement at any gear stage. Has been devised (see Patent Document 1).

  However, due to recent demands for improving the fuel efficiency of vehicles due to environmental problems, etc., for example, small vehicles and the like are required to have multiple stages of automatic transmissions, and the number of frictional engagement elements for forming a shift stage is required. It tends to increase. In addition, from the viewpoint of vehicle mountability, the automatic transmission is also required to be downsized at the same time, and this tendency is particularly noticeable in the case of a small vehicle with a small mounting space. When the off-valve is used, the increase in the gear position not only prevents the hydraulic control device from being made compact, but also hinders weight reduction and cost reduction.

  Thus, a shift control device for an automatic transmission has been devised in which fail-safe is not guaranteed mechanically like the above-described cut-off valve, but attempts fail-safe by control (see Patent Document 2). The shift control device described in Patent Document 2 includes a first shift threshold value that is a value between the gear ratios before and after the shift, and a second shift threshold value that is a value obtained by multiplying the gear ratio before the shift by a safety factor. And comparing the time until the actual gear ratio becomes the first gear shift threshold value without becoming the second gear shift threshold value with a preset detection time, thereby determining the fail state as the “air blow state” or It is configured so that it can be distinguished between the “drag state”.

JP 2003-336731 A JP 2007-255518 A

  As described in Patent Document 2, when a failure is detected based on a change in gear ratio during a predetermined time, it is possible to determine whether the failure is on the release side or on the engagement side. Depending on the length of the timer, there is a possibility that the failure detection condition does not change and the failure cannot be detected accurately.

  Specifically, assuming that the speed ratio progress rate is a failure detection condition, in the case of a coast down shift in which the frictional engagement element is slowly changed with an emphasis on the reduction of the speed change shock, the speed ratio also gradually changes. Therefore, if the timer is set in the same way as a downshift (power-on-down shift) other than coast down, in which the shift is finished in a short time with an emphasis on response, the timer will be There is a possibility that the progress rate of the transmission ratio becomes equal to or less than the threshold value and is judged to be a failure. Therefore, there has been a problem that a failure cannot be detected in the coast downshift.

  Therefore, an object of the present invention is to provide a control device for an automatic transmission that can accurately determine the failure (release failure) of the disengagement side frictional engagement element even in a coast downshift.

According to the first aspect of the present invention, a plurality of friction engagement elements (C-1, C-2) that are engaged based on the engagement pressure supplied to each hydraulic servo (41, 42, 43, 44, 45). , C-3, B-1, B-2), an input shaft (8) connected to the drive source (2), and an output shaft connected to the drive wheel, the plurality of frictional engagements A plurality of transmission paths between the input shaft (8) and the output shaft are changed based on the engagement state of the combination elements (C-1, C-2, C-3, B-1, B-2). In the control device (1) of the automatic transmission (3) that forms a shift speed of
Downshift determining means (76) for determining whether the downshift is a coast downshift or a downshift other than the coast downshift at the time of downshift;
Fail determination timer setting means (86) for setting the time of the failure determination timer (t ₀ ) based on the downshift determination means (76);
A fail determination timer starting means (87) for starting the fail determination timer (t ₀ ) based on the determination of the start of downshift.
Fail determination means for determining a release failure of the release side frictional engagement element based on the end of the fail determination timer,
The fail determining timer setting means (86) sets the time of the fail determining timer (t ₀ ) to a downshift other than the coast downshift when the coast downshift is determined by the downshift determining means (76). Set longer than the time (t ₀ ′) of the fail determination timer (86) at the time of shifting (t ₀ > t ₀ ′),
The control device (1) of the automatic transmission (3) is characterized by the above.

According to the second aspect of the present invention, among the plurality of friction engagement elements (C-1, C-2, C-3, B-1, B-2), an engagement side friction engagement element (for example, C- 1) a shift timer setting means (85) for setting an engagement control time (t ₂ ) for actually engaging 1) and a completion control time (t ₃ ) for completing the shift;
The fail determination timer setting means (86) determines the end point (d) of the fail determination timer (t ₀ ) at the time of the coast down shift from the start point (a) of the engagement control time (t ₂ ). Set to (t ₄ ) during the end point (c) of the completion control time (t ₃ ),
A control device (1) for an automatic transmission (3) according to claim 1.

According to a third aspect of the present invention, the fail determination timer setting means (86) includes an end point (d) of the fail determination timer (t ₀ ) during the coast down shift and the completion control time (t ₃ ). The time of the fail determination timer (t ₀ ) is set so that the start time (c) of
A control device (1) for an automatic transmission (3) according to claim 2.

According to a fourth aspect of the present invention, the fail determination timer setting means (86) determines an end point (d) of the fail determination timer (t ₀ ) at the time of the coast down shift as an engagement side frictional engagement element ( For example, the torque capacity of C-1) is set at a time point (t ₄ ) that surely affects the rotation change of the input shaft.
A control device (1) for an automatic transmission (3) according to any one of claims 1 to 3.

According to a fifth aspect of the present invention, when the fail determination means (79) determines that the release is defective, the fail-safe execution means performs a fail action that interrupts the downshift and shifts to the shift stage before the start of the shift. (80)
A control device (1) for an automatic transmission (3) according to any one of claims 1 to 4.

  Note that the reference numerals in the parentheses are for comparison with the drawings, but this is for convenience to facilitate understanding of the invention and has no influence on the description of the claims. It is not a thing.

  According to the first aspect of the present invention, there is a possibility that the failure may be erroneously detected by setting the fail determination timer at the time of the coast downshift longer than that at the time of the downshift other than the coast downshift. Even in the coast downshift where the failure cannot be detected, it is possible to accurately determine the release failure of the release side frictional engagement element.

  According to the second aspect of the present invention, the end point of the fail determination timer is from the start point of the engagement control time for engaging the engagement side frictional engagement element to the end point of the completion control time for completing the shift. By setting in between, it is possible to determine the release failure of the release side frictional engagement element with high accuracy.

  According to the invention of claim 3, by setting the end time of the fail determination timer to a time close to the start time of the completion control time, it is possible to prevent the fail determination after the end of the shift, and at an early stage. The release failure of the release side frictional engagement element can be determined, and the fail-a cushion can be performed at an early stage.

  According to the fourth aspect of the present invention, since the end point of the fail determination timer is set at a time point at which the change in the input shaft speed is surely affected, the input shaft speed as a fail detection condition is surely changed. Since the failure determination can be performed after the occurrence, the release failure of the release side frictional engagement element can be determined with higher accuracy.

  According to the fifth aspect of the present invention, when the fail safe execution unit determines that the release is defective by the fail determination unit, the fail safe execution unit executes a fail action that interrupts the downshift and shifts to the shift stage before the start of the shift. Therefore, it is possible to continue running at a gear stage that does not cause a problem in running by returning to the gear position that does not release the disengagement-side frictional engagement element that has been determined to be poorly released, that is, the gear stage before the start of gear shifting. it can.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below with reference to FIGS.

[Schematic configuration of automatic transmission]
First, a schematic configuration of an automatic transmission 3 to which the present invention can be applied will be described with reference to FIG. As shown in FIG. 2, an automatic transmission 3 suitable for use in, for example, an FF type (front engine, front drive) vehicle is an automatic transmission 3 that can be connected to an engine (drive source) 2 (see FIG. 1). An input shaft 8 is provided, and a torque converter 4 and an automatic transmission mechanism 5 are provided around the axial direction of the input shaft 8.

  The torque converter 4 includes a pump impeller 4a connected to the input shaft 8 of the automatic transmission 3, and a turbine runner 4b to which the rotation of the pump impeller 4a is transmitted via a working fluid. The runner 4 b is connected to the input shaft 10 of the automatic transmission mechanism 5 disposed coaxially with the input shaft 8. Further, the torque converter 4 is provided with a lock-up clutch 7, and when the lock-up clutch 7 is engaged, the rotation of the input shaft 8 of the automatic transmission 3 causes the input shaft of the automatic transmission mechanism 5 to rotate. 10 is transmitted directly.

  The automatic transmission mechanism 5 includes clutches C-1, C-2, C-3 and brakes B-1, which are engaged based on engagement pressures respectively supplied to the hydraulic servos 41 to 45 (see FIG. 5). B-2, an input shaft 10 connected to the engine 2, and a counter gear 11 connected to a drive wheel (not shown), the clutches C-1, C-2, C-3, brake B -1 and B-2 are used to change the transmission path between the input shaft 10 and the counter gear 11 to form a plurality of shift stages. The automatic transmission mechanism 5 includes an input shaft 10, a planetary gear SP and a planetary gear unit PU are provided. The planetary gear SP is a so-called single pinion planetary gear that includes a sun gear S1, a carrier CR1, and a ring gear R1, and has a pinion P1 that meshes with the sun gear S1 and the ring gear R1.

  The planetary gear unit PU has a sun gear S2, a sun gear S3, a carrier CR2, and a ring gear R2 as four rotating elements. The carrier CR2 has a long pinion PL that meshes with the sun gear S2 and the ring gear R2, and the sun gear S3. This is a so-called Ravigneaux type planetary gear that has meshing short pinions PS that mesh with each other.

  The sun gear S <b> 1 of the planetary gear SP is connected to a boss portion that is integrally fixed to the mission case 9, and the rotation is fixed. The ring gear R1 is in the same rotation as the rotation of the input shaft 10 (hereinafter referred to as “input rotation”). Further, the carrier CR1 is decelerated by reducing the input rotation by the fixed sun gear S1 and the ring gear R1 that rotates, and the clutch (friction engagement element) C-1 and the clutch (friction engagement). Element) connected to C-3.

  The sun gear S2 of the planetary gear unit PU is connected to a brake B-1 formed of a band brake so as to be freely fixed to the transmission case, and is connected to the clutch C-3 via the clutch C-3. Thus, the decelerated rotation of the carrier CR1 can be input. The sun gear S3 is connected to the clutch C-1, so that the decelerated rotation of the carrier CR1 can be input. The brake B-1 has a brake band 19 provided around a drum-shaped member 18 connected to the clutch C-3 and the sun gear S2. The brake band 19 is fixed to the case 9 at one end. The other end is connected to a hydraulic servo 44 (see FIG. 5), which will be described later, and is wound around the drum-shaped member 18 by driving the hydraulic servo 44. The winding direction of the brake band 19 is disposed so as to be opposite to the rotation direction of the drum-shaped member 18 from the second forward speed to the sixth forward speed. The winding is performed by pulling in the reverse direction from the rotational speed at the sixth forward speed from the speed stage.

  Further, the carrier CR2 is connected to a clutch C-2 to which the rotation of the input shaft 10 is input, and the input rotation can be freely input through the clutch C-2, and the one-way clutch F-1 and Connected to the brake B-2, rotation in one direction is restricted with respect to the transmission case via the one-way clutch F-1, and rotation can be fixed via the brake B-2. The ring gear R2 is connected to a counter gear (output shaft) 11, and the counter gear 11 is connected to a driving wheel (not shown) via a counter shaft (not shown) and a differential device.

[Operation of each gear stage in automatic transmission]
Next, based on the above configuration, the operation of the automatic transmission mechanism 5 will be described with reference to FIGS. 2, 3, and 4. In the velocity diagram shown in FIG. 4, the vertical axis indicates the rotational speed of each rotating element (each gear), and the horizontal axis indicates the gear ratio of these rotating elements. Further, in the planetary gear SP portion of the velocity diagram, the vertical axis corresponds to the sun gear S1, the carrier CR1, and the ring gear R1 in order from the left side in FIG. Furthermore, in the planetary gear unit PU of the velocity diagram, the vertical axis corresponds to the sun gear S3, the ring gear R2, the carrier CR2, and the sun gear S2 in order from the right side in FIG.

  For example, in the D (drive) range and the first forward speed (1ST), as shown in FIG. 3, the clutch C-1 and the one-way clutch F-1 are engaged. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S3 via the clutch C-1. Further, the rotation of the carrier CR2 is restricted in one direction (forward rotation direction), that is, the carrier CR2 is prevented from rotating in the reverse direction and is fixed. Then, the decelerated rotation input to the sun gear S3 is output to the ring gear R2 via the fixed carrier CR2, and the forward rotation as the first forward speed is output from the counter gear 11.

  During engine braking (coast), the brake B-2 is locked to fix the carrier CR2, and the forward first speed state is maintained by preventing the carrier CR2 from rotating forward. . Further, at the first forward speed, the one-way clutch F-1 prevents the carrier CR2 from rotating in the reverse direction and enables forward rotation, so that the first forward speed when switching from the non-traveling range to the traveling range, for example. Can be smoothly achieved by the automatic engagement of the one-way clutch F-1.

  At the second forward speed (2ND), as shown in FIG. 3, the clutch C-1 is engaged and the brake B-1 is locked. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S3 via the clutch C-1. Further, the rotation of the sun gear S2 is fixed by the locking of the brake B-1. Then, the carrier CR2 is decelerated and rotated at a speed lower than that of the sun gear S3, the decelerated rotation input to the sun gear S3 is output to the ring gear R2 via the carrier CR2, and the forward rotation as the second forward speed is counter gear. 11 is output.

  In the third forward speed (3RD), as shown in FIG. 3, the clutch C-1 and the clutch C-3 are engaged. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S3 via the clutch C-1. Further, the reduced rotation of the carrier CR1 is input to the sun gear S2 by the engagement of the clutch C-3. That is, since the reduction rotation of the carrier CR1 is input to the sun gear S2 and the sun gear S3, the planetary gear unit PU is directly connected to the reduction rotation, and the reduction rotation is output to the ring gear R2 as it is, and the forward rotation as the third forward speed is performed. Output from the counter gear 11.

  At the fourth forward speed (4TH), as shown in FIG. 3, the clutch C-1 and the clutch C-2 are engaged. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S3 via the clutch C-1. Further, the input rotation is input to the carrier CR2 by engaging the clutch C-2. Then, by the decelerated rotation input to the sun gear S3 and the input rotation input to the carrier CR2, the rotation speed is higher than the third forward speed and is output to the ring gear R2, and the forward rotation as the fourth forward speed is performed. The rotation is output from the counter gear 11.

  At the fifth forward speed (5TH), as shown in FIG. 3, the clutch C-2 and the clutch C-3 are engaged. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated and rotated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S2 via the clutch C-3. Further, the input rotation is input to the carrier CR2 by the engagement of the clutch C-2. Then, due to the decelerated rotation input to the sun gear S2 and the input rotation input to the carrier CR2, the rotation speed is slightly higher than the input rotation and is output to the ring gear R2, which is the forward rotation as the fifth forward speed. Is output from the counter gear 11.

  At the sixth forward speed (6TH), as shown in FIG. 3, the clutch C-2 is engaged and the brake B-1 is locked. Then, as shown in FIGS. 2 and 4, the input rotation is input to the carrier CR2 by the engagement of the clutch C-2. Further, the rotation of the sun gear S2 is fixed by the locking of the brake B-1. Then, the input rotation of the carrier CR2 becomes higher than the forward fifth speed by the fixed sun gear S2, and is output to the ring gear R2, and the forward rotation as the sixth forward speed is output from the counter gear 11. .

  In the first reverse speed (REV), as shown in FIG. 3, the clutch C-3 is engaged and the brake B-2 is locked. Then, as shown in FIGS. 2 and 4, the rotation of the carrier CR1 that is decelerated and rotated by the fixed sun gear S1 and the ring gear R1 that is the input rotation is input to the sun gear S2 via the clutch C-3. Further, the rotation of the carrier CR2 is fixed by the locking of the brake B-2. Then, the decelerated rotation input to the sun gear S2 is output to the ring gear R2 via the fixed carrier CR2, and the reverse rotation as the first reverse speed is output from the counter gear 11.

  For example, in the P (parking) range and the N (neutral) range, the clutch C-1, the clutch C-2, and the clutch C-3 are released. Then, the carrier CR1, the sun gear S2, and the sun gear S3, that is, the planetary gear SP and the planetary gear unit PU are disconnected, and the input shaft 10 and the carrier CR2 are disconnected. Thereby, the power transmission between the input shaft 10 and the planetary gear unit PU is disconnected, that is, the power transmission between the input shaft 10 and the counter gear 11 is disconnected.

[Schematic configuration of hydraulic control unit]
Next, the hydraulic control device 6 for an automatic transmission according to the present invention will be described. First, generation parts such as a line pressure, a secondary pressure, a modulator pressure, and a range pressure, which are not shown in the hydraulic control device 6 (see FIG. 1), will be roughly described. The generation portions of the line pressure, secondary pressure, modulator pressure, and range pressure are the same as those of a general automatic transmission hydraulic control device, and are well-known and will be described briefly.

  The hydraulic control device 6 includes, for example, an oil pump, a manual shift valve, a primary regulator valve, a secondary regulator valve, a solenoid modulator valve, a linear solenoid valve SLT, and the like (not shown). For example, the engine 2 (see FIG. 1) When started, the oil pump that is rotationally connected to the pump impeller 4a of the torque converter 4 is driven in conjunction with the rotation of the engine 2 to suck up oil from an oil pan (not shown) through a strainer. Generate hydraulic pressure in the form.

Hydraulic pressure generated by the oil pump, on the basis of a signal pressure P _SLT of the linear solenoid valve SLT that is pressure regulating output according to the throttle opening degree, the pressure is adjusted to a line pressure P _L being discharged adjusted by the primary regulator valve . The line pressure P _L is the manual shift valve, the solenoid modulator valve, and more information is supplied to the linear solenoid valve SLC3 to be described later. The line pressure P _L supplied to the solenoid modulator valve of this is pressure regulated to a modulator pressure P _MOD to be substantially constant pressure by the valve, the modulator pressure P _MOD is the original pressure, such as the linear solenoid valve SLT Supplied as

The pressure discharged from the primary regulator valve is adjusted to the secondary pressure _PSEC while being further discharged and adjusted by, for example, the secondary regulator valve, and this secondary pressure _PSEC is supplied to, for example, a lubricating oil passage or an oil cooler. And also supplied to the torque converter 4 and used to control the lock-up clutch 7.

On the other hand, a manual shift valve (not shown) has a spool that is mechanically (or electrically) driven by a shift lever provided in a driver's seat (not shown), and the position of the spool is controlled by the shift lever. selected shift range (e.g. P, R, N, D) by being switched according to, to set the output state or non-output state of the line pressure P _L the input (drain).

In particular, when the D range based on the operation of the shift lever, through said line pressure P _L is communicated with the input port to be input and a forward range pressure output port based on the position of the spool, the forward range pressure output line from the port pressure P _L is output as a forward range pressure (D range pressure) P _D. When based on the operation of the shift lever to the R (reverse) range, communicates with the input port and the reverse range pressure output port based on the position of the spool, the line pressure P _L rear proceeds range pressure output port reverse range Pressure (R range pressure) _PREV is output. Further, when the P range and the N range are set based on the operation of the shift lever, the input port, the forward range pressure output port and the reverse range pressure output port are blocked by the spool, and the forward range pressure output. port and the reverse range pressure output port are communicated with the drain port, that is, the non-output state D range pressure P _D and the R range pressure P _REV are drained (discharged).

[Configuration of shift control portion in hydraulic control device]
Next, a portion that mainly performs shift control in the hydraulic control device 6 according to the present invention will be described with reference to FIG. FIG. 5 is a circuit diagram schematically showing an excerpt of the hydraulic control device 6 of the automatic transmission. The hydraulic control device 6 includes the hydraulic servo 41 for the clutch C-1, the hydraulic servo 42 for the clutch C-2, the hydraulic servo 43 for the clutch C-3, the hydraulic servo 44 for the brake B-1, and the brake B-2. Four linear solenoid valves SLC1, SLC2, SLC3, and SLB1 for directly supplying output pressures adjusted as engagement pressures to each of a total of five hydraulic servos of the hydraulic servo 45 are provided. In addition, a switching valve 23 that achieves a limp home function and switches the output pressure of the linear solenoid valve SLC2 to the hydraulic servo 42 of the clutch C-2 or the hydraulic servo 45 of the brake B-2 is provided. The switching valve 23 is not actually a single valve, but a solenoid valve (not shown), a first clutch apply relay valve, a second clutch apply relay valve, a C-2 relay valve, a B-2 relay valve, or the like. It is drawn in an aggregated form.

A forward range pressure output port (not shown) of the manual shift valve described above is connected to the oil passage a1 to the linear solenoid valve SLC1, the oil passage a4 to the linear solenoid valve SLC2, and the oil passage a5 to the linear solenoid valve SLB1. is configured to forward range pressure P _D can be input Te, in addition, the oil passage d to the linear solenoid valve SLC3, the line pressure P _L from the primary regulator valve (not shown) is input.

The linear solenoid valve SLC1 is of a normally closed type that when not energized in a non-output state, the input port SLC1a for receiving the forward range pressure P _D via the oil path a1, by regulating the forward range pressure P _D and an output port SLC1b for outputting as the engagement pressure _{P C1} control pressure _{P SLC1} to the hydraulic servo 41 Te.

The linear solenoid valve SLC2 is a normally open type that attains an outputting state when being de-energized, the input port SLC2a for receiving the forward range pressure P _D via the oil path a4, and by regulating the forward range pressure P _D The hydraulic servo 42 has an output port SLC2b that outputs the control pressure P _SLC2 as the engagement pressure P _C2 (or engagement pressure P _B2 ).

The linear solenoid valve SLC3 is a normally open type that attains an outputting state when being de-energized, the input port SLC3a which inputs the line pressure P _L via the oil passage d, the hydraulic servo by regulating the line pressure P _L and an output port SLC3b for outputting a control pressure _{P SLC3} as the engagement pressure _{P C3} to 43.

The linear solenoid valve SLB1 is of a normally closed type that when not energized in a non-output state, the input port SLB1a for receiving the forward range pressure P _D through the oil passage a5, by regulating the forward range pressure P _D and an output port SLB1b to output as the engagement pressure _{P B1} control pressure _{P SLB1} to the hydraulic servo 44 Te.

[Configuration of automatic transmission control device]
Next, the control apparatus 1 for an automatic transmission according to the present invention will be described mainly with reference to FIG.

  As shown in FIG. 1, the control device 1 of the automatic transmission includes a control unit (ECU) 70, which includes an accelerator opening sensor 81, an input shaft rotational speed sensor 83, an output shaft. A rotation speed (vehicle speed) sensor 82 and a speed change operation unit 84 that outputs a range signal are connected, and are connected to the linear solenoid valves SLC1, SLC2, SLC3, SLB1, etc. of the hydraulic control device 6 described above. In addition, an engine speed signal and an engine torque signal are sent from the engine 2 to the control unit 70.

The control unit 70 includes a hydraulic pressure command means 71 having a normal time hydraulic pressure setting means 72, an input torque detection means 73, a torque sharing determination means 74, a shift determination means 75, and a shift map map. Further, the control unit 70 is provided with a shift progress rate calculation means 78, a downshift determination means 76, an engagement pressure monitoring means 77, a fail determination means 79, and a fail safe execution means 80. determining means 79 is a fail determination timer setting means 86 for setting a failure determination timer t ₀ which performs failure determination, and a failure determination timer start means 87 for starting the failure determination timer t _0.

  The shift determination means 75 refers to the shift map map based on the accelerator opening detected by the accelerator opening sensor 81 and the vehicle speed detected by the output shaft rotational speed sensor 82, and the above-mentioned first forward speed to The sixth forward speed is determined. That is, an upshift shift line and a downshift shift line (shift point) corresponding to the accelerator opening and the vehicle speed are recorded in the shift map map, and the accelerator opening and the vehicle speed at that time exceed these shift lines. Then, the shift determination means 75 determines the shift. The shift speed (current shift speed) determined by the shift determination means 75 is output to the hydraulic pressure command means 71 and the torque sharing determination means 74.

  On the other hand, the input torque detection means 73 inputs an engine torque signal from the engine 2 to measure the engine torque and detect the input torque currently input to the input shaft 10 of the automatic transmission mechanism 5. Further, the torque sharing determination means 74 is based on the gear determined by the shift determination means 75, and the torque sharing in the clutch or brake (see FIG. 3) engaged in the automatic transmission mechanism 5, that is, each gear ratio. Based on the above, the ratio to the input torque required in the clutch or brake is determined (calculated).

  Next, the normal time hydraulic pressure setting means 72 multiplies the torque sharing in the engaged clutch or brake determined by the torque sharing determination means 74 according to the gear position, and further multiplies the safety factor. The torque sharing value and the input torque detected by the input torque detecting means 73 are multiplied to calculate the torque capacity (transmission torque) of the engaged clutch or brake, and the number, area, The engagement pressure (control pressure) to be supplied to the hydraulic servo of the clutch or brake being engaged is calculated from the pressure receiving area of the hydraulic servo.

  Based on the engagement pressure set by the normal-time hydraulic pressure setting means 72, the hydraulic pressure command means 71 supplies the engagement pressure to the hydraulic servo of the clutch or brake being engaged. An electric command is given to the solenoid valves SLC1, SLC2, SLC3, SLB1, that is, during traveling under normal conditions, the clutch and brake are engaged so as to obtain a torque capacity in which a safety factor is added to the input torque. Even if the torque fluctuates or receives torque fluctuations from the driving wheels due to road conditions or the like, the clutch and the brake are engaged so as not to slip.

[Automatic transmission control]
Next, the shift control of the automatic transmission, in particular, the fail-safe control in the shift control at the coast down shift which is the main part of the present invention will be described in detail. First, the hydraulic control of the disengagement side frictional engagement element at the time of coast down shift will be described.

When the shift determining means 75 refers to the shift map map based on the signals from the accelerator opening sensor 81 and the output shaft rotational speed sensor 82 and determines a coast downshift, a shift signal is output to the hydraulic pressure command means 71, A coast down shift is started based on the shift signal. Further, when the downshift is determined by the shift determining means 75, whether the coast is down by the downshift determining means 76 based on signals from the accelerator opening sensor 81, the output shaft rotational speed sensor 82, and the shift operating section 84. Then, it is determined whether the other downshift (for example, power-on downshift) is performed. As shown in FIG. 6, the release-side hydraulic pressure PA at this time has a engaging pressure, the shifting is initiated the disengagement side pressure PA is sliding out of the frictional engagement element in the release preparation control time t ₁ Sweep down to the previous hydraulic pressure and wait (release preparation control S20).

Releasing the release preparation control (S20) is completed, the release side hydraulic pressure PA is in the engagement control time t ₂ to be described later, and as quickly swept down can within the shift shock does not occur, the release-side friction engagement element (Inertia phase control S25, completion control S55)

Next, hydraulic control of the frictional engagement element on the engagement side will be described. Engagement hydraulic pressure PB, corresponding to the start of the release preparation control of the above-described disengagement side pressure PA (S20), rises abruptly in the inner release preparation control time t _1, the frictional engagement element hydraulic servo piston Is immediately moved to immediately before the engagement (servo activation control S20 which is so-called backlash control).

When the servo activation control (S20) is completed, the engagement side hydraulic pressure PB is kept at a low pressure and is gradually increased to close the piston stroke and actually engage the friction engagement element slowly ( The process proceeds to S25). Proceeds to completion control and engagement control time t ₂ has elapsed (S55), once raised the engagement hydraulic pressure PB to the engaged pressure fully engaging the engagement side frictional engagement element.

Next, fail safe control will be described. By the shift determination means 75 as described above is the shift start determination, the change signal is output to the fail determination timer starting means 87, a fail detection timer t ₀ set by the failure determination timer setting unit 86 start To do. The failure determination timer t ₀ is a timer to determine when the fail decision unit 79 performs the fail determination, set the predetermined time has elapsed fail decision unit 79, the determination conditions, such as the shift progress degree ShiftR The failure is determined based on the above.

Also, the coast downshift, because the shift shock to proceed slowly shifting without causing, the failure determination timer t ₀ is set longer than the other downshift (e.g. power-on downshift) Yes.

  The shift progress rate ShiftR is calculated based on the rotation speed of the input shaft 10 supplied from the input shaft rotation speed sensor 83 and the counter gear 11 supplied from the output shaft rotation speed sensor 82 during the shift by the shift progress rate calculation means 78. This value is calculated based on the degree of reach from the speed ratio to the speed ratio of the next gear to be shifted.

Therefore, failure determination timer setting means 86, complete control end d of the fail determination timer t _0, the start point a of the engagement control shift progress degree ShiftR ranges up as possible to proceed (S25) ( can be set in a range within t ₄ of the end c of S55), the engagement control as described above (S25) is gently for engaging the engagement side frictional engagement element, the input shaft 8 Completion control (time t) in which the change in rotation speed is poor or may shift to a later time point, and at the end time point d, the engagement-side frictional engagement element is engaged at once and the change in the input shaft rotation speed inRPM is surely changed. ₃ ) Set in ().

In addition, the above-described range until the shift progress rate ShiftR is fully advanced means that the engagement side frictional engagement element is actually engaged and the torque capacity of the engagement side frictional engagement element is the input shaft 10 (or 8). ) In the range affecting the rotation change, that is, within the range from when the input shaft rotational speed inRPM starts to rise until this rise is completely finished and reaches an equilibrium state. Further, the end d of the fail determination timer t ₀ is immediately before the torque capacity of the engagement side frictional engagement element as engagement control in (time t ₃₎ the end affects the speed change of the input shaft 10 Alternatively, it is desirable that the setting is made after the influence on the rotational speed change of the input shaft 10 is finished.

Further, the failure determination, it is necessary to determine the release failure of the disengagement side frictional engagement element during the shift, end d of the fail determination timer t _0, even during the completion control, the start of possible completion control It is set to a time point close to the time point b, and is set so that a failure to release the frictional engagement element can be determined at an early stage.

Note that failure determination timer t ₀ is the frictional engagement element on the engagement side is started engages rising input shaft speed InRPM, whereby if a normal control state shift progress degree to fail decision ShiftR Is set to a period longer than the time that is sufficiently advanced.

  Next, the operation of the present invention will be described. As shown in FIG. 7, when a signal from the accelerator opening sensor 81 and the output shaft rotational speed sensor 82 is sent to the hydraulic pressure command means 71 so that the shift determination means 75 performs a downshift, a downshift determination is made. The means 76 determines whether the shift is a coast down shift or a shift other than the coast down shift (for example, a power-on down shift) (S1).

The downshift determining means 76, when it is determined that the coast downshift failure determination timer setting unit 86 sets the failure determination timer t ₀ greater than during other downshift for coast downshift control (T ₀ > t ₀ ′) After the failure determination timer t ₀ has elapsed (S2), the failure determination means 79 determines whether or not the engagement side hydraulic pressure PB exceeds the first engagement pressure threshold N ₁ . It is determined (S3).

At this time, if the engagement-side oil pressure PB does not exceed the _first engagement pressure threshold value N1, the change in the rotation speed of the input shaft rotation speed inRPM does not occur due to the engagement failure (the shift progress rate shiftR is progressing). This step is repeated because it is not possible to determine that the frictional engagement element has failed.

Incidentally, the first engagement pressure threshold N ₁ and second engagement pressure threshold N ₂ to be described _later, the third engagement pressure threshold N ₃ is sufficiently engaged frictional engagement element of the engagement side during transmission It is set to a value that can only be combined (torque capacity during engagement control).

When the engagement hydraulic pressure PB is greater than the first engagement pressure threshold N _1, the shift progress degree shiftR by fail decision means 79 is sufficiently beyond if if the normal shift control is fail determination timer t ₀ elapses the value that should have and, it is determined less than or shift progress rate threshold G ₁ which is set to a value that does not erroneously detect a failure (S4), when shift progress degree shiftR the following shift progress rate threshold G _1, released It is determined that the side frictional engagement element is not released (S5).

  When it is determined that the disengagement side frictional engagement element has failed, the fail safe execution means 80 outputs a control signal to the hydraulic pressure command means 71, interrupts the downshift being executed, and returns to the gear stage before the start of the shift. After performing the action (S6), the shift control is terminated (S7).

Further, in the fail determination, after the case of the shift progress degree shiftR is shift progress rate threshold G ₁ or more, were normal shift control regarded as normal speed state (S8), and ends the shift control (S9).

On the other hand, when it is determined by the downshift determining means 76 that the coast downshift control is not performed, as shown in FIG. 8, the fail determination timer setting means 86 is used for power on downshift control and part of manual downshift control. The failure determination timer t ₀ ′ is set. When the failure determination timer t ₀ ′ elapses (S10), the downshift determination means 76 determines whether or not the engine torque exceeds a predetermined value (S11), and when this engine torque exceeds the predetermined value. Is determined to be manual down shift control, and when the engine torque does not exceed a predetermined value, it is determined to be power on down shift control.

If it is determined that the manual downshift control, the value and the second engagement pressure threshold N ₂ the engagement hydraulic pressure PB are compared by fail decision means 79 (S12), the value of the engagement-side oil pressure PB is second for less than the engagement pressure threshold N _2, the flow returns to step 11 as does not satisfy the hydraulic conditions. Moreover, even when it is determined that the power-on downshift control, the value of the engagement side hydraulic PB and the third engagement pressure threshold N ₃ are compared by the failure determining means 79 (S13), the engaging hydraulic pressure PB If the value is less than the third engagement pressure threshold N _3, it returns to step 11 as does not satisfy the hydraulic conditions.

In the manual downshift control and a power-on downshift control, if the value of the engagement hydraulic pressure PB is greater than the third engagement pressure threshold N _3, and the value of the shift progress degree shiftR like the coast down shift control It is compared with the shift progress rate threshold value _{G 1} (S4), if the shift progress degree shiftR the following shift progress rate threshold _{G 1} is implemented fail action (S5, S6) the shift control is completed. Also, shift progress degree shiftR is after the normal control is regarded as normal in the case of shift progress rate threshold G ₁ or more, and terminates the shift control (S8, S9).

By configuring the control apparatus 1 for the automatic transmission as described above, by which the failure determination timer t ₀ longer than when the other downshift during coasting downshift, release side even during coast downshift It is possible to detect defective release of the friction engagement element. Further, the end d of the fail determination timer t _0, the engagement side frictional engagement element is engaged at once engaged, the increase in the input shaft rotational speed is substantially completed, complete control of the shift progress degree shiftR proceeds largely by set to a time t _3, the difference between the normal shift state is increased, it is possible to easily accurately determine the release failure of the release side frictional engagement element.

Furthermore, the end d of the fail determination timer t _0, by setting the time as close as possible to the beginning b of the completion control, it is possible to prevent that the failure determination after the shift end, the release-side friction engagement early The failure to release the combined element can be determined, and the failure action can be prepared early.

  Further, when the fail-safe execution means determines that the release failure is determined by the fail determination means, the fail-safe execution means executes the fail action that interrupts the downshift and shifts to the shift stage before the start of the shift. By returning to the gear position that does not release the disengagement-side frictional engagement element determined to be defective, that is, the gear position before the start of gear shifting, it is possible to continue traveling at a gear position that does not cause a problem in traveling. It should be noted that the fail action does not necessarily have to be returned to the shift stage before the shift, and may be shifted to another shift stage as long as the failed release side frictional engagement element is not released.

  Moreover, although the automatic transmission 3 of the present embodiment described above has been described as an example that can achieve the sixth forward speed, the automatic transmission to which the present invention can be applied is not limited thereto. Of course, other types of automatic transmissions may be used.

The block diagram which shows the control apparatus of the automatic transmission which concerns on this invention. The skeleton figure which shows the automatic transmission which can apply this invention. The engagement table of this automatic transmission mechanism. The speed diagram of this automatic transmission mechanism. FIG. 2 is a circuit diagram schematically showing an excerpt of a hydraulic control device of the automatic transmission. The time graph figure which shows the change of each part in the case of coast down shift. The flowchart explaining the effect | action of the control apparatus of this automatic transmission. The time graph which shows the change of each part in the case of a power on down shift.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus of automatic transmission 2 Drive source 10 Input shaft 11 Output shaft 41,42,43,44,45 Hydraulic servo 76 Downshift discrimination means 79 Fail judgment means 80 Fail safe execution means 85 Shift timer setting means 86 Fail judgment Timer setting means t ₀ , t ₀ ′ Fail judgment timer t ₂ Engagement control time t ₃ Completion control time a Engagement control start time b Completion control start time c Completion control end time d Fail judgment timer End point C-1, C-2, C-3, B-1, B-2 Friction engagement element

Claims (5)

A plurality of friction engagement elements engaged based on engagement pressures respectively supplied to the respective hydraulic servos, an input shaft connected to a drive source, and an output shaft connected to a drive wheel, An automatic transmission that changes a transmission path between the input shaft and the output shaft based on an engagement state of a plurality of friction engagement elements to form a plurality of shift speeds and performs a gripping change shift of the friction engagement elements. In the control device of the machine,
Downshift determining means for determining whether the downshift is a coast downshift or a downshift other than the coast downshift during a downshift;
A fail determination timer setting means for setting a time of a fail determination timer based on the downshift determination means;
Fail determination timer starting means for starting the fail determination timer based on the start determination of the downshift,
Fail determination means for determining a release failure of the release side frictional engagement element based on the end of the fail determination timer,
The fail determination timer setting means, when a coast downshift is determined by the downshift determination means, determines the time of the fail determination timer from the time of the fail determination timer at the time of a downshift other than the coast downshift. Set too long,
A control device for an automatic transmission. A shift timer setting means for setting an engagement control time for actually engaging the engagement-side friction engagement element among the plurality of friction engagement elements and a completion control time for completing the shift;
The fail determination timer setting means sets the end point of the fail determination timer at the time of the coast down shift between the start point of the engagement control time and the end point of the completion control time.
The control device for an automatic transmission according to claim 1. The fail determination timer setting means sets the time of the fail determination timer so that the end point of the fail determination timer at the time of the coast down shift is close to the start point of the completion control time.
The control apparatus for an automatic transmission according to claim 2. The fail determination timer setting means sets the end point of the fail determination timer at the time of the coast down shift to a time when the torque capacity of the engagement side frictional engagement element surely affects the change in the rotational speed of the input shaft. Become
The control device for an automatic transmission according to any one of claims 1 to 3. When the fail determination means determines that the release failure is made, the apparatus further includes fail-safe execution means for performing a fail action for interrupting the downshift and shifting to a gear position before starting the shift.
The control device for an automatic transmission according to any one of claims 1 to 4.

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