JP4725175B2 - Automatic transmission failure detection device - Google Patents

Description

  The present invention relates to a failure detection device for an automatic transmission, and belongs to the technical field of an automatic transmission for a vehicle.

  As is well known, an automatic transmission mounted on a vehicle such as an automobile combines a torque converter and a transmission gear mechanism, and selectively selects a plurality of friction elements such as a clutch and a brake on a power transmission path of the transmission gear mechanism. It is configured to automatically set the gear stage according to the operating state by fastening and switching, and the torque converter has an input side and an output side in an operating region where the torque increasing action is not required. In some cases, a lock-up clutch is provided for the purpose of improving the fuel efficiency by directly connecting the two. In addition to being completely engaged or released, the lock-up clutch may be subjected to slip control that causes the input side and the output side to slip at a predetermined rotational difference in order to improve fuel consumption and emissions.

  In such an automatic transmission, the hydraulic pressure control circuit controls the operating pressure supplied to each of the friction elements and the lockup clutch so as to control the gear stage and the engagement / release of the lockup clutch. The hydraulic control circuit is provided with various solenoid valves for generating, supplying / discharging, and regulating the operating pressure, and the operation of these solenoid valves is controlled by an electrical control signal. Thus, the operating pressure supplied to the friction element and the lock-up clutch is controlled.

  By the way, in the case of the configuration as described above, when the solenoid valve fails, a predetermined friction element is not fastened or released with respect to the shift command output according to the operation state, so that the gear stage as commanded is obtained. Or the lock-up clutch is not engaged or released according to the command. Therefore, various methods for detecting such a failure have been proposed.

  For example, Patent Document 1 discloses a method for detecting a lock-up on failure in which the lock-up clutch is completely engaged although a control signal is sent so that the lock-up clutch performs release or slip control. Is disclosed.

  In this method, a rotation difference between the input side and the output side of the lockup clutch is detected, and a failure is determined based on the rotation difference. In other words, the rotation difference between the input side and the output side becomes large when the lockup clutch is released, and the rotation difference corresponding to the control signal is realized in the slip control, but the lockup clutch is released. In this state, an abnormality is detected when the rotation difference between the input side and the output side is small or a rotation difference smaller than the rotation difference expected by the slip control is detected. Then, when the rotation difference data between the input side and the output side is continuously collected and the time when the abnormality in which the rotation difference is equal to or less than a predetermined threshold is detected as a failure determination condition exceeds a predetermined determination time, It is determined that a failure has occurred.

  Further, Patent Document 2 discloses a method for detecting a gear error failure in which a target gear stage is not achieved with respect to a shift command.

In this method, the actual gear ratio is calculated based on the input rotation speed and the output rotation speed of the transmission gear mechanism, and the actual gear ratio is compared with the gear ratio of the target gear stage stored in advance. Anomalies are detected when is outside the allowable range. Then, when the actual gear ratio data is continuously collected and the time when an abnormality that deviates from the allowable range is detected as a failure determination condition exceeds a predetermined determination time, the occurrence of the failure is determined. ing.
JP 11-280893 A JP-A-11-280886

  By the way, the above-described determination of the lock-up on failure is performed in the region between the shift lines in the shift control map. As shown in FIG. 7, a slip region for performing the slip control may be provided adjacent to a shift line on the low throttle opening side at a predetermined shift stage. In this case, the low throttle opening of the shift stage is provided. In the region, the lock-up off region becomes very narrow.

  Similarly, the gear error failure described above is performed in the region between the shift lines. However, the shift control map is set so that the gaps between the shift lines become narrow as the transmission is multistaged. In particular, the lower the throttle opening side, the narrower the interval between the shift lines, so that the region of each gear stage becomes narrower in the low throttle opening region.

  On the other hand, the determination accuracy of such a lock-up on failure or gear error failure improves as the determination time is set longer.

  However, when driving at a low throttle opening corresponding to the frequently used urban driving mode, the driving state is not stable, and the above-mentioned narrow area passes through in a short time. Easy to overlook. In order to prevent this, it is conceivable to set the failure determination condition so that the determination time is shortened, or to set the failure determination condition so that the determination threshold value makes it easier to detect the failure. There arises a problem that an erroneous determination that the state is a failure is likely to occur.

  Accordingly, an object of the present invention is to accurately perform failure determination without causing erroneous determination even in a case where a region that can be used for failure determination of a control map is narrow in an automatic transmission failure detection device. .

  In order to solve the above problems, the present invention is configured as follows.

First, the invention according to claim 1 of the present application is provided in an automatic transmission that performs shift control according to a driving state based on a preset control map, and in a predetermined determination region provided in the control map. A failure detection device for an automatic transmission having a failure determination means for performing a failure determination based on a predetermined failure determination condition, wherein a failure has not been determined by the failure determination means with respect to the failure determination condition. Preliminary failure determination means for performing failure determination based on a preliminary failure determination condition set so as to facilitate occurrence determination, and determination of the control map when the occurrence of failure is determined by the preliminary failure determination means Determination area changing means for enlarging the area, and the failure determination means is configured to change the determination area change means when the preliminary failure determination means determines that a failure has occurred. Performs failure determination in a more enlarged determination area, when the vehicle is stopped, the preliminary malfunction determination means returns to a state in which the determination of the failure is not made, the determination area changing means before larger expanded determination area It changes to the area | region of this.

  The determination area changing unit may change the control map to a control map in which the determination area is enlarged, or may change the shift line and each area so that the determination area is enlarged on the control map.

  According to a second aspect of the present invention, there is provided the automatic transmission failure detection device according to the first aspect, wherein the failure determination means and the preliminary failure determination means are configured to lock up the fluid transmission device in a lock-up off region. It is characterized by determining a lock-up on failure in which the clutch is abnormally engaged.

  Examples of the fluid transmission device include a torque converter and a fluid coupling.

  Furthermore, the invention according to claim 3 is the automatic transmission failure detection device according to claim 1, wherein the failure determination means and the preliminary failure determination means have a gear ratio that deviates from the gear ratio of the target gear. It is characterized in that a gear error failure is determined.

  Next, according to a fourth aspect of the present invention, in the automatic transmission failure detection device according to any one of the first to third aspects, the failure determination means and the preliminary failure determination means are in an operating state. It is characterized in that a failure determination is performed when in a low load region.

  According to a fifth aspect of the present invention, in the automatic transmission failure detection device according to any one of the first to fourth aspects, the failure determination condition is that the duration of the abnormal state is a predetermined determination time. It is set so that the occurrence of a failure is determined when the time is exceeded, and the determination time of the preliminary failure determination condition is set to be shorter than the predetermined determination time.

  According to a sixth aspect of the present invention, in the automatic transmission failure detection device according to any one of the first to fourth aspects, the failure determination condition is a comparison between a detection value and a predetermined determination threshold value. In this case, the determination of occurrence of failure is set, and the determination threshold value of the preliminary failure determination condition is set to a normal value side with respect to the predetermined determination threshold value.

According to the first aspect of the present invention, the failure determination is first performed by the preliminary failure determination means. Since the preliminary failure determination condition at this time is set so as to make it easy to determine the occurrence of the failure, a failure sign is reliably detected. Then, when a failure sign is detected, the determination area of the control map is expanded by the determination area changing unit, and a normal failure determination is performed by the failure determination unit. In this failure determination means, failure determination is performed based on normal failure determination conditions, but since the determination area of the control map is expanded, sufficient time for determination is secured and it is possible to prevent overlooking the failure Is done. Then, by returning the enlarged determination area to the area before enlargement as a result of the determination of the occurrence of the failure by the preliminary failure determination means when the vehicle is stopped, it is possible to avoid long-time driving with the changed control map. Since this is performed particularly when the vehicle is stopped, the uncomfortable feeling caused by suddenly changing the control map during driving is prevented.

  Next, according to the invention described in claim 2, by applying the invention described in claim 1 to the determination of the lock-up on failure in which the lock-up clutch is abnormally engaged, the lock-up on with high accuracy is achieved. A failure determination is made. In this case, a remarkable effect is obtained when the lock-up off region corresponds to the determination region and the lock-up off region is narrowed by providing the slip region.

  Further, according to the invention described in claim 3, by applying the invention described in claim 1 to the determination of a gear error failure in which the gear ratio deviates from the gear ratio of the target gear, the gear error failure can be accurately detected. A determination will be made. In this case, the region of each shift stage corresponds to the determination region, and a remarkable effect can be obtained particularly when the number of shift stages is increased and the distance between the shift lines is narrow.

  By the way, when the driving state is in the low load region, it corresponds to the urban driving mode with high use frequency, and therefore, a highly accurate failure detection is desired. This is because, even if an accurate failure determination is performed in a high load area where a wide area that can be used for the determination can be secured, the frequency of use of this area is low, so failure detection is delayed.

  On the other hand, according to the invention described in claim 4, since the invention described in claim 1 is applied when the operation state is in the low load region where the usage frequency is high, the accuracy in the low load region is achieved. Thus, when a failure determination is made and a failure occurrence determination is made, it is possible to quickly take measures such as failure warning and fail-safe control. Further, for example, when the above-described two-stage failure determination is performed only in the low load region where the operation state is a predetermined value or less, when the throttle opening is equal to or greater than the predetermined value, only the normal failure determination is performed. Since it is good, simplification of control can be achieved.

  Further, according to the invention described in claim 5, when the failure determination condition is set so that a failure is determined when the duration of the abnormal state exceeds the predetermined determination time, compared to the failure determination condition Since the determination time of the preliminary failure determination condition is set to be short, even if the determination region is a narrow region, the preliminary failure determination means can reliably detect a failure occurrence sign.

  For example, in the determination of the lockup on failure according to the second aspect of the present invention, the time during which the rotational difference between the input side and the output side of the lockup clutch is smaller than the predetermined determination threshold exceeds the predetermined determination time. When it is configured to sometimes determine the occurrence of a failure, a determination is first made using a preliminary failure determination condition in which a determination time is set shorter than the failure determination condition. Then, after a sign of failure occurrence is detected, the lock-up off region in the control map is expanded, and regular failure determination is performed based on the failure determination condition. As a result, even when the lock-up off region is narrow, the determination of the lock-up on failure is performed with high accuracy.

  In the determination of the gear error failure according to the third aspect of the present invention, when the time when the actual gear ratio deviates from the allowable range exceeds the predetermined determination time, the occurrence of the failure is determined. First, a determination is made based on a preliminary failure determination condition in which a determination time is set shorter than the failure determination condition. Then, after a failure occurrence sign is detected, an area related to the gear position in the control map is expanded, and regular failure determination is performed based on the failure determination condition. As a result, even if the region formed between the shift lines is narrow due to the multi-stage, the determination of the gear error failure is performed accurately without causing an erroneous determination by the two-step failure determination.

  Furthermore, according to the invention described in claim 6, since the determination threshold value of the preliminary failure determination condition is set to the normal value side compared to the failure determination condition, the preliminary failure is determined even if the determination region is narrow. By the determination, a sign of failure occurrence is surely detected.

  For example, in the determination of the lock-up on failure according to the second aspect of the present invention, when the failure occurrence is determined when the rotational difference between the input side and the output side of the lock-up clutch is small. First, in order to detect a sign of occurrence of a failure, a determination is made based on a preliminary failure determination condition in which the rotation difference that is a determination threshold for failure determination is set large. Then, after a failure occurrence sign is detected, the lockup-off area in the control map is expanded, and a normal failure determination is performed based on a failure determination condition in which the rotation difference that is a failure determination threshold is set to be small. . As a result, even when the lock-up off region is narrow, the determination of the lock-up on failure is performed with high accuracy.

  In the determination of a gear error failure according to the third aspect of the present invention, the actual gear ratio formed based on the input rotation speed and the output rotation speed of the transmission gear mechanism is compared with the gear ratio of the target gear stage. Therefore, when the actual gear ratio deviates from the allowable range, first, the normal allowable range is set to be small as the determination threshold in order to detect the occurrence of the failure. The determination is made based on the preliminary failure determination condition. Then, after the sign of failure occurrence is detected, the region of the gear stage in the control map is expanded, and failure determination is performed based on a failure determination condition in which a normal allowable range is set large as a determination threshold. As a result, even when the region formed between the transmission lines is narrow due to the multi-stage, the gear error failure is accurately determined.

  Embodiments of the present invention will be described below.

  First, the mechanical configuration of the automatic transmission 10 according to this embodiment will be described with reference to FIG.

  The automatic transmission 10 includes, as main components, a torque converter 20, a transmission gear mechanism 30 driven by the output of the torque converter 20, and a plurality of frictions such as a clutch and a brake for switching a power transmission path of the mechanism 30. The elements 41 to 45 and the one-way clutch 46 are provided, and thereby, the 1st to 4th speeds in the forward range such as the D, S, and L ranges and the reverse speed in the R range are obtained.

  The torque converter 20 includes a pump 22 fixed in a case 21 connected to the engine output shaft 1, and a turbine 23 that is disposed facing the pump 22 and is driven by the pump 22 via hydraulic oil. And a stator 25 interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via a one-way clutch 24 to increase the torque, and between the case 21 and the turbine 23. The lockup clutch 26 is provided and directly connects the engine output shaft 1 and the turbine 23 via the case 21. The rotation of the turbine 23 is output to the transmission gear mechanism 30 via the turbine shaft 27.

  Here, an oil pump 12 driven by the engine output shaft 1 via a case 21 of the torque converter 20 is disposed on the opposite side of the torque converter 20 from the engine.

  On the other hand, the gear transmission mechanism 30 includes sun gears 31a and 32a, a plurality of pinions 31b and 32b engaged with the sun gears 31a and 32a, and pinion carriers 31c and 32c that support the pinions 31b and 32b, respectively. The first and second planetary gear mechanisms 31 and 32 have internal gears 31d and 32d engaged with the pinions 31b and 32b.

  A forward clutch 41 is provided between the turbine shaft 27 and the sun gear 31a of the first planetary gear mechanism 31, and a reverse clutch 42 is provided between the turbine shaft 27 and the sun gear 32a of the second planetary gear mechanism 32. A 3-4 clutch 43 is interposed between the turbine shaft 27 and the pinion carrier 32c of the second planetary gear mechanism 32, and a 2-4 brake 44 for fixing the sun gear 32a of the second planetary gear mechanism 32 is provided. Has been placed.

  Further, an internal gear 31d of the first planetary gear mechanism 31 and a pinion carrier 32c of the second planetary gear mechanism 32 are connected, and a low reverse brake 45 and a one-way clutch 46 are connected between these and the transmission case 11. The pinion carrier 31c of the first planetary gear mechanism 31 and the internal gear 32d of the second planetary gear mechanism 32 are connected to each other, and the output gear 13 is connected to them. The rotation of the output gear 13 is transmitted to the left and right axles 6 and 7 via the transmission gears 2, 3, 4 and the differential mechanism 5.

  Here, the relationship between the operating states of the friction elements 41 to 45 such as the clutches and brakes and the one-way clutch 46 and the gears is summarized as shown in Table 1 below. In Table 1, (◯) indicates a case where the friction element is fastened. Further, (◎) in the column of the low reverse brake 45 indicates that it is engaged only in the L range.

次に、前記各摩擦要素４１〜４５に設けられた油圧室に対して作動圧を給排する油圧制御回路１００について説明する。

Next, the hydraulic control circuit 100 that supplies and discharges the operating pressure to the hydraulic chambers provided in the friction elements 41 to 45 will be described.

  Of the friction elements, the 2-4 brake 44 for the 2nd and 4th speeds, which is a band brake, has an apply chamber 44a and a release chamber 44b as hydraulic chambers to which operating pressure is supplied. When the operation pressure is supplied only to 44a, the 2-4 brake 44 is engaged, and when the operation pressure is supplied only to the release chamber 44b, the operation pressure is not supplied to both the chambers 44a and 44b. When the operating pressure is supplied to both chambers 44a and 44b, the 2-4 brake 44 is released. The other friction elements 41 to 43, 45 have a single hydraulic chamber, and the friction element is fastened when an operating pressure is supplied to the hydraulic chamber.

  As shown in FIG. 2, the hydraulic control circuit 100 includes, as main components, a regulator valve 101 that generates line pressure, a manual valve 102 that switches a range by manual operation, and operates at the time of shifting. A low reverse valve 103, a bypass valve 104, a 3-4 shift valve 105 and a lock-up shift valve 106 for switching an oil passage leading to each of the friction elements 41 to 45, and a first and a first for operating these valves 103 to 106 2 On / Off Solenoid Valves (hereinafter referred to as “On / Off SV”) 111, 112 and Solenoid Reducing Valves (hereinafter referred to as “Reducing Valve”) 107 for generating a source pressure supplied to these On / Off SVs 111, 112 And the supply destination of the operating pressure from the first on / off SV 111 A solenoid relay valve (hereinafter referred to as “relay valve”) 108 to be switched, and first to third duty solenoids for controlling generation, adjustment, discharge and the like of the operating pressure supplied to the hydraulic chambers of the friction elements 41 to 45. Valves (hereinafter referred to as “duty SV”) 121, 122, 123 and the like are provided.

  Here, the on / off SVs 111 and 112 and the duty SVs 121 to 123 are all three-way valves, and a state where the upper and downstream oil passages are communicated and a state where the downstream oil passage is drained is obtained. It is supposed to be. In the latter case, since the upstream oil passage is blocked, the operating oil from the upstream side is not discharged in a drained state, and the drive loss of the oil pump 12 is reduced.

  When the on / off SVs 111 and 112 are on, the upper and downstream oil passages communicate with each other. When the duty SVs 121 to 123 are off, that is, when the duty ratio (the ratio of the on time in one on-off cycle) is 0%, the duty SV 121 to 123 is fully opened, and the upper and downstream oil passages are completely communicated, When ON, that is, when the duty ratio is 100%, the upstream oil passage is shut off and the downstream oil passage is made into a drain state, and at the intermediate duty ratio, the upstream oil pressure is used as the original pressure. The hydraulic pressure adjusted to a value corresponding to the duty ratio is generated on the downstream side.

  The regulator valve 101 adjusts the pressure of the hydraulic oil discharged from the oil pump 12 to a predetermined line pressure. The line pressure is supplied to the manual valve 102 via the main line 200 and also to the reducing valve 107 and the 3-4 shift valve 105.

  The line pressure supplied to the reducing valve 107 is reduced to a constant pressure by the valve 107 and then supplied to the first and second on / off SVs 111 and 112 via the lines 201 and 202.

  This constant pressure is supplied to the relay valve 108 via the line 203 when the first on / off SV 111 is on, and when the spool of the relay valve 108 is located on the right side in the drawing (the same applies hereinafter). Further, the pressure is supplied as a pilot pressure to the control port 104a at one end of the bypass valve 104 via the line 204, and the spool of the bypass valve 104 is urged to the left side. When the spool of the relay valve 108 is located on the left side, this constant pressure is supplied as a pilot pressure to the control port 105a at one end of the 3-4 shift valve 105 via the line 205, and the 3-4 shift valve The 105 spool is biased to the right.

  When the second on / off SV 112 is on, the constant pressure from the reducing valve 107 is supplied to the bypass valve 104 via the line 206, and when the spool of the bypass valve 104 is located on the right side. Further, it is supplied as a pilot pressure to the control port 106a at one end of the lockup control valve 106 via the line 207, and the spool of the control valve 106 is urged to the left side. Further, when the spool of the bypass valve 104 is located on the left side, it is supplied as a pilot pressure to the control port 103a at one end of the low reverse valve 103 via the line 208, and urges the spool of the low reverse valve 103 to the left side. .

  Further, the constant pressure from the reducing valve 107 is also supplied to the pressure regulating port 101 a of the regulator valve 101 via the line 209. In this case, the constant pressure is adjusted according to, for example, an engine load or the like by a linear solenoid valve (hereinafter referred to as “linear SV”) 131 provided in the line 209. It will be adjusted according to the load and the like.

  The main line 200 led to the 3-4 shift valve 105 is connected to the first accumulator 141 via the line 210 when the spool of the valve 105 is located on the right side, and the line pressure is applied to the accumulator 141. Introduce.

  On the other hand, the line pressure supplied from the main line 200 to the manual valve 102 is in the first output line 211 and the second output line 212 in the D, S, and L forward ranges, and in the R range, the first output line 211 and It is introduced into the third output line 213, and in the N range, it is introduced into the third output line 213, respectively.

  The first output line 211 is guided to a first duty SV121 and supplies a line pressure as a control source pressure to the first duty SV121. The downstream side of the first duty SV 121 is guided to the low reverse valve 103 via the line 214. When the spool of the valve 103 is located on the right side, the 2-4 brake 44 is further connected via the line 215. When the spool of the low reverse valve 103 is located on the left side, it is further guided to the hydraulic chamber of the low reverse brake 45 via the line 216. Here, a line 217 is branched from the line 214 and led to the second accumulator 142.

  The second output line 212 is led to a second duty SV122 and a third duty SV123, and supplies a line pressure as a control source pressure to these duties SV122 and 123, respectively, and also to the 3-4 shift valve 105. Led. The line 212 led to the 3-4 shift valve 105 is led to the lock-up shift valve 106 via the line 218 when the spool of the valve 105 is positioned on the left side, and the spool of the valve 106 is moved to the left side. When positioned, it is further guided to the hydraulic chamber of the forward clutch 41 via the line 219.

  Here, the line 220 branched from the forward clutch line 219 is led to the 3-4 shift valve 105, and when the spool of the valve 105 is located on the left side, the first accumulator 141 is passed through the line 210 described above. In addition, when the spool of the valve 105 is positioned on the right side, it communicates with the release chamber 44b of the 2-4 brake 44 via the line 221.

  The downstream side of the second duty SV 122 to which the control source pressure is supplied from the second output line 212 is led to the control port 108a at one end of the relay valve 108 via the line 222 to supply the pilot pressure, The spool of the relay valve 108 is urged to the left side, and the line 223 branched from the line 222 is led to the low reverse valve 103 and further leads to the line 224 when the spool of the valve 103 is located on the right side. .

  A line 225 is branched from the line 224 via an orifice 151. The branched line 225 is led to the 3-4 shift valve 105, and the spool of the 3-4 shift valve 105 is positioned on the left side. At this time, it is guided to the release chamber 44 b of the 2-4 brake 44 through the line 221.

  Further, a line 226 is further branched from the line 225 branched from the line 224 via the orifice 151. The line 226 is led to the bypass valve 104, and the spool of the valve 104 is located on the right side. Sometimes, it is guided to the hydraulic chamber of the 3-4 clutch 43 via the line 227.

  Further, the line 224 is directly led to the bypass valve 104 and communicates with the line 225 via the line 226 when the spool of the valve 104 is located on the left side. That is, the line 224 and the line 225 pass through the orifice 151.

  Further, the downstream side of the third duty SV 123 to which the control source pressure is supplied from the second output line 212 is led to the lock-up shift valve 106 via the line 228, and the spool of the valve 106 is positioned on the right side. , And communicates with the forward clutch line 219. Further, when the spool of the lockup shift valve 106 is located on the left side, it communicates with the front chamber 26a of the lockup clutch 26 via the line 229.

  Further, the third output line 213 from the manual valve 102 is led to the low reverse valve 103 to supply the line pressure to the valve 103. When the spool of the valve 103 is positioned on the left side, the valve 103 is guided to the hydraulic chamber of the reverse clutch 42 via the line 230.

  Similarly, the line 231 branched from the third output line 213 is led to the bypass valve 104, and when the spool of the valve 104 is located on the right side, the control port 103a of the low reverse valve 103 is connected via the line 208 described above. A line pressure is supplied as a pilot pressure to urge the spool of the low reverse valve 103 to the left.

  In addition to the above configuration, the hydraulic control circuit 100 is provided with a converter relief valve 109. The valve 109 adjusts the operating pressure supplied from the regulator valve 101 via the line 232 to a constant pressure, and then supplies this to the lock-up shift valve 106 via the line 233. The constant pressure is supplied to the front chamber 26a of the lockup clutch 26 via the above-described line 229 when the spool of the lockup shift valve 106 is positioned on the right side. Is positioned on the left side, it is supplied to the rear chamber 26b of the lockup clutch 26 via a line 234.

  Here, the lock-up clutch 26 is released when the constant pressure is supplied to the front chamber 26a, and is engaged when the constant pressure is supplied to the rear chamber 26b. At the time of fastening, when the spool of the lockup shift valve 106 is positioned on the left side, the working pressure generated by the third duty SV 123 is supplied to the front chamber 26a, so that the fastening force corresponding to this working pressure is obtained. It has come to be obtained.

  Further, in the hydraulic control circuit 100, as described above, the line pressure adjusted by the regulator valve 101 is controlled to, for example, the hydraulic pressure according to the engine load by the control pressure from the linear SV 131. The line pressure is also controlled. That is, a line 235 led from the manual valve 102 and leading to the main line 200 in the D, S, L and N ranges is connected to the pressure reducing port 101b of the regulator valve 101, and the D, S, L and N In the range, the line pressure adjustment value is set lower than that in the R range.

  On the other hand, as shown in FIG. 3, a controller 300 that controls the first and second on / off SVs 111 and 112, the first to third duty SVs 121 to 123 and the linear SV 131 in the hydraulic pressure control circuit 100 is provided.

The controller 300 includes a vehicle speed sensor 301 that detects a vehicle speed of the vehicle, a throttle opening sensor 302 that detects a throttle opening as an engine load, an engine speed sensor 303 that detects an engine speed, and a driver selected. Inhibitor switch 304 for detecting the range, turbine rotational speed sensor 305 for detecting the rotational speed of turbine shaft 27 which is the input rotational speed to transmission gear mechanism 30, and output rotational speed sensor for detecting the output rotational speed of transmission gear mechanism 30 306, signals from an oil temperature sensor 307 or the like for detecting the oil temperature of the hydraulic oil are input, and the on / off SV 111 according to the operation state of the vehicle or engine indicated by the signals from these sensors and the switches 301 to 307 , 112, duty SV 121-123 and linear SV1 And controls the first operation.

  Next, the relationship between the operating states of the first and second on / off SVs 111 and 112 and the first to third duty SVs 121 to 123 and the supply / discharge state of the operating pressure with respect to the hydraulic chambers of the friction elements 41 to 45 will be described.

  Here, combinations of operating states (solenoid patterns) of the first and second on / off SVs 111 and 112 and the first to third duty SVs 121 to 123 for each gear position are set as shown in Table 2 below. .

  In Table 2, (O) is on for the on / off SVs 111 and 112, and is off for the duty SVs 121 to 123. In both cases, the upstream oil passage is connected to the downstream oil passage, and the original pressure is set. The state of supplying to the downstream side as it is is shown. Further, (x) is off for the on / off SVs 111 and 112, and is on for the duty SVs 121 to 123, both of which are in a state where the upstream oil passage is blocked and the downstream oil passage is drained. Show. Further, (x (duty)) for the third duty SV123 indicates that the downstream side is drained or that the operating pressure is generated on the downstream side by duty control.

以上の変速段のうち、本件特徴部分を４速を例に説明する。

Of the above gear positions, the characteristic part of the present invention will be described using the fourth speed as an example.

  As shown in Table 2 and FIG. 4, in the fourth speed, the first duty SV 121 is operated, and the operating pressure is generated using the line pressure from the first output line 211 as a source pressure. This operating pressure is supplied to the low reverse valve 103 via the line 214. At this time, the spool of the low reverse valve 103 is positioned on the right side, so that the operation pressure is further introduced into the line 215 and the 2-4 brake 44. Is supplied as a servo apply pressure to the apply chamber 44a. Thereby, the 2-4 brake 44 is fastened.

  Since the line 214 communicates with the second accumulator 142 via the line 217, the supply of the servo apply pressure and the engagement of the 2-4 brake 44 are performed gradually.

  In addition to this state, the second duty SV 122 is also operated to generate an operating pressure using the line pressure from the second output line 212 as a source pressure. This operating pressure is supplied to the low reverse valve 103 via the line 222 and the line 223. At this time, the spool of the valve 103 is positioned on the right side, and is further introduced into the line 224.

  The operating pressure generated by the second duty SV 122 is introduced from the line 224 to the line 225 through the orifice 151 and is guided to the 3-4 shift valve 105. Further, since the line 226 is further branched from the line 225 branched from the line 224 via the orifice 151, the operating pressure is guided to the bypass valve 104 by the line 226, and at this time, the bypass valve When the spool of 104 is positioned on the right side, it is further supplied as a 3-4 clutch pressure to the hydraulic chamber of the 3-4 clutch 43 via the line 227.

  As described above, the second duty SV 122 generates an operating pressure, which is supplied to the control port 108a of the relay valve 108 via the line 222, whereby the spool of the relay valve 108 moves to the left side.

  Further, by the operation of the first on / off SV 111, a constant pressure from the line 201 is supplied to the relay valve 108 via the line 203. As described above, the spool of the relay valve 108 moves to the left side. Therefore, the constant pressure is supplied to the control port 105a of the 3-4 shift valve 105 via the line 205, and the spool of the valve 105 moves to the right side.

  Therefore, the line 221 leading to the release chamber 44b of the 2-4 brake 44 and the line 220 branched from the line 219 leading to the forward clutch 41 are connected via the 3-4 shift valve 105, and the 2-4 brake 44 The release chamber 44b communicates with the hydraulic chamber of the forward clutch 41.

  Then, as described above, the third duty SV 123 stops generating the operating pressure and puts the downstream side into the drain state, so that the operating pressure in the release chamber 44b of the 2-4 brake 44 and the hydraulic chamber of the forward clutch 41 is reduced. The third duty SV 123 is drained through the lock-up shift valve 106 and the line 228. Thereby, the 2-4 brake 44 is reengaged and the forward clutch 41 is released.

  When the lock-up clutch 26 is engaged in the fourth speed state, as shown in Table 2 and FIG. 5, the second on / off SV 112 is first activated with respect to the fourth speed state, thereby reducing the reducing valve. A constant pressure from 107 is supplied to the control port 106a of the lockup shift valve 106 via the second on / off SV 112, line 206, bypass valve 104 and line 207, and the spool of the lockup shift valve 106 is moved to the left. .

  At this time, in the lockup clutch 26, the third duty SV 123 causes the front of the front to be supplied by the third duty SV123 while the rear chamber 26b is supplied with a constant pressure from the converter relief valve 109 (see FIG. 2) via the lines 233 and 234. The operating pressure in the chamber 26a is adjusted by discharge or duty control. As a result, the lockup clutch 26 is controlled to be engaged or slipped.

  Further, the third duty SV 123 stops generating the operating pressure, while the first on / off SV 111 operates. Accordingly, since the spool of the 3-4 shift valve 105 is positioned on the right side, the line 219 leading to the forward clutch 41 and the line 221 leading to the release chamber 44b of the 2-4 brake 44 are connected via the line 220. In a connected state, the lock up shift valve 106 is guided to the lock up shift valve 106. These lines 219 and 221 are further connected via the line 218 because the spool of the lock up shift valve 106 is located on the left side as described above. It is guided to the 3-4 shift valve 105 and communicates with the drain port 105 b of the valve 105.

  Therefore, when the lockup clutch 26 is engaged in the fourth speed state, the forward clutch pressure and the servo release pressure are discharged from the drain port 105b of the 3-4 shift valve 105 from the state where the forward clutch pressure and the servo release pressure are discharged by the third duty SV123. Thus, the disengaged state of the forward clutch 41 and the engaged state of the 2-4 brake 44 are maintained.

  By the way, the solenoid valves 111, 112, 121 to 123 have a function failure, that is, a plunger stick or leak due to foreign matter biting, etc., despite the ON / OFF signal and duty signal being normally supplied from the controller 300. Or due to mechanical failure such as malfunction of the plunger due to breakage of the spring, the hydraulic supply / discharge operation and pressure adjustment operation to the friction element may not be performed according to the control signal. The gear stage as commanded is not obtained, or the lock-up clutch is on (engaged) or off (released) as commanded, or from the non-traveling range such as the N range to the D range. There is a possibility that the engaging operation of the friction element at the time of the switching operation to the traveling range, etc., may not be performed as instructed.

  Therefore, the controller 300 determines whether or not the gear position matches the command, whether or not the state of the lockup clutch 26 matches the command, or whether or not the engagement operation is performed as instructed. Etc., and if it is not in accordance with the command, it is determined from the abnormal state which solenoid valve 111, 112, 121 to 123, what kind of malfunction has occurred, and Appropriate fail-safe control is performed according to the determination result.

  Here, the relationship between the malfunction of the solenoid valve and the abnormality of the gear stage and the lock-up clutch 26 caused thereby is as shown in Table 3 below.

  In Table 3, “off failure” for each solenoid valve is a functional failure that is in an off state even when the signal is on, and for the on / off SVs 111 and 112, the friction element from the hydraulic power source side. That is, the operating pressure is not supplied to the side, and the duty SV 121 to 123 is a state in which the operating pressure is supplied from the hydraulic source side to the friction element side. The “on failure” is a functional failure that is turned on even when the signal is off, and the on / off SVs 111 and 112 are in a state in which operating pressure is supplied from the hydraulic power source side to the friction element side. In other words, the duty SVs 121 to 123 are in a state where the operating pressure is not supplied from the hydraulic pressure source side to the friction element side.

  In the following description, for example, a command for turning the gear stage to the fourth speed and turning off the lockup clutch 26 is “fourth speed command”, and a command for turning the gear stage to the fourth speed and turning on the lockup clutch 26 is “fourth speed lock”. "Up command", etc., and an abnormality in which the actual gear is different from the command or in neutral is called "gear error failure", and an error that causes the lock-up clutch 26 to turn off in response to an on command. An abnormality that is turned on in response to a “lockup-off failure” and an off command is referred to as a “lockup-on failure”, and an abnormality in which the engagement operation is not performed as commanded is referred to as an “engage failure”.

表３に示すように、第２オンオフＳＶ１１２のオン故障時には、４速指令時にロックアップクラッチ２６が締結されるロックアップオン故障が発生する。

As shown in Table 3, when the second on / off SV 112 is on-failed, a lock-up on failure occurs in which the lock-up clutch 26 is engaged at the time of the fourth speed command.

  That is, in the state of the fourth speed shown in FIG. 4, when the second on / off SV is turned on, the pilot pressure is supplied to the control port 106a of the lock-up shift valve 106 via the line 206, the bypass valve 104, and the line 207, The spool of the lock-up shift valve 106 is positioned on the left side. Therefore, the constant pressure from the line 233 is supplied to the rear chamber 26b of the lockup clutch 26 via the lockup shift valve 106 and the line 234, and at the same time, the operating pressure of the front chamber 26a is changed to the line 229, lockup shift. The third duty SV 123 is drained through the valve 106 and the line 228. As a result, the lockup clutch 26 is in an engaged state different from the command. Note that the state of the hydraulic circuit in the fourth-speed lockup-on failure is the same as the fourth-speed lockup state shown in FIG.

  Next, the determination control for such a 4-speed lock-up on failure will be described based on the flowchart of FIG. This determination control corresponds to the gist of the invention described in claims 1 and 2.

  As shown in FIG. 7, in the control map, a slip region is set adjacent to the shift line on the low throttle opening side. Note that the determination of the 4-speed lock-up on failure described below is made when a certain accelerator depression amount or more is detected.

  First, in step S1, it is determined whether or not the vehicle is stopped. If the vehicle is not stopped, the process proceeds to step S2, and it is determined whether or not the flag FRAG1 is zero. When the flag FRAG1 is zero, the process proceeds to step S3 to determine whether or not the flag FRAG2 is zero. When the flag FRAG2 is zero, the process proceeds to step S4, and it is determined whether or not the operating state is within the 4-speed lockup off region.

  And when it determines with a driving | running state being in the 4th speed lockup off area | region by step S4, preliminary failure determination is performed by step S5. In this preliminary failure determination, the preliminary failure determination condition is satisfied when the state where the difference between the engine speed and the turbine speed is 50 rpm or less continues for 0.5 sec. In the normal failure determination described later, the failure determination condition is satisfied when the difference between the engine speed and the turbine speed is 30 rpm or less continues for 1 sec. The preliminary failure determination condition is relatively easy to detect a failure. At this time, by setting the preliminary failure determination condition to be satisfied when the state where the rotation difference is 30 rpm or less continues for 0.5 sec, or when the state where the rotation difference is 50 rpm or less continues for 1 sec, You may comprise so that only one of a rotation difference or duration may differ with respect to failure determination conditions.

  When the preliminary failure determination condition is satisfied, the process proceeds to step S6, where the flag FRAG1 is set to 1 as a failure occurrence determination, and the 4-speed lock up / off region is expanded in step S7. The occurrence of failure in the preliminary failure determination is low in reliability because conditions are relatively easily satisfied, and the possibility that an actual failure has occurred is relatively low, and only a sign of failure is detected.

  Further, the enlargement of the lock-up off region is realized by reducing the slip region provided in the lock-up off region or eliminating the slip region as shown in FIG. As a result, as shown in the control map of FIG. 7, a wider determination area X ′ than the determination area X is secured.

  Next, regular failure determination is performed in step S8. In this failure determination, the failure determination condition is satisfied when the state where the difference between the engine speed and the turbine speed is 30 rpm or less continues for 1 second. When the failure determination condition is satisfied, the process proceeds to step S9, where the flag FRAG2 is set to 1 as a failure occurrence determination, and a failure warning and predetermined failsafe control are performed in step S10. It should be noted that the occurrence of a failure in the failure determination is a stricter condition than the preliminary failure determination, so the reliability is high and the possibility that a failure has actually occurred is extremely high.

  On the other hand, when it is determined in step S1 that the vehicle is stopped, the process proceeds to step S11, where the flag FRAG1 is reset to zero. In step S12, the 4-speed lockup region is expanded in step S7. Initializes this area to the area before enlargement.

  If it is determined in step S2 that the flag FRAG1 is not zero, that is, if the preliminary failure determination condition has already been satisfied, the process proceeds to step S8, where a normal failure determination is performed.

  If it is determined in step S3 that the flag FRAG2 is not zero, that is, if the failure determination condition is already satisfied, the process proceeds to step S10, and the failure warning and failsafe control are continued. In other words, if FRAG2 is set to 1 even once in step S9, the flag FRAG2 is not reset to zero in this determination control, and the failure warning and fail-safe control are repeated. It will be reset when done.

  On the other hand, when the driving state is not in the 4-speed lockup off region in step S4, the process returns to step S1. Even during the shift, the gear ratio is not stable, so the preliminary failure determination is not performed and the process returns to step S1.

  Further, when the preliminary failure determination condition is not satisfied at step S5 and when the failure determination condition is not satisfied at step S8, the process returns to step S1.

The step S5 corresponds to the gist of the invention described in claims 5 and 6, and the steps S11 and S12 correspond to the gist of the invention described in claim 1 .

  Next, gear error failure determination control will be described with reference to the flowchart of FIG. This determination control corresponds to the gist of the inventions described in claims 1 and 3.

  Here, a case will be described in which a gear error failure is determined when a third-speed shift command is issued, as in the shift map of FIG. Note that the determination of the gear error failure is made when the conditions that the oil temperature is appropriate, the turbine rotation speed equal to or greater than the predetermined value is normally detected, and the gear is not being shifted are satisfied. ing.

  First, in step S21, it is determined whether or not the vehicle is stopped. If the vehicle is not stopped, the process proceeds to step S22, and it is determined whether or not the flag FRAG1 is zero. If the flag FRAG1 is zero, the process proceeds to step S23 to determine whether or not the flag FRAG2 is zero. When the flag FRAG2 is zero, the process proceeds to step S24 to determine whether or not the operating state is in the third speed region.

  If it is determined in step S24 that the operating state is in the third speed region, preliminary failure determination is performed in step S25. In this preliminary failure determination, the state where the actual gear ratio calculated based on the rotational difference between the input side and the output side of the transmission gear mechanism has an error of 5% or more with respect to the gear ratio of the target gear stage is 0. The preliminary failure judgment condition is satisfied when it lasts for 5 seconds. In the normal failure determination described later, the failure determination condition is satisfied when a state having an error of 10% or more continues for 1 second, but the preliminary failure determination condition is compared with this. It is easy to detect mechanical failure. At this time, by setting the preliminary failure determination condition to be satisfied when a state having an error of 10% or more continues for 1 second, or when a state having an error of 5% or more continues for 0.5 seconds Alternatively, it may be configured such that only one of the allowable range or duration is different from the normal failure determination condition.

  When the preliminary failure determination condition is satisfied, the process proceeds to step S26 where the flag FRAG1 is set to 1 as a failure occurrence determination, and the third speed region is expanded in step S27. The occurrence of a failure in the preliminary failure determination is low in reliability because conditions are relatively easily satisfied, and it is unlikely that a failure has actually occurred, and only a sign of failure is detected.

  Further, the expansion of the third speed region is realized by increasing the speed of the 3-4 shift line as shown in FIG. As a result, as shown in the control map of FIG. 10, a wider determination area Y ′ than the determination area Y is secured.

  Next, regular failure determination is performed in step S28. In this failure determination, the failure determination condition is satisfied when a state where the actual gear ratio has an error of 10% or more with respect to the gear ratio of the target shift stage continues for 1 second. When the failure determination condition is satisfied, the process proceeds to step S29, where the flag FRAG2 is set to 1 as a failure occurrence determination, and a failure warning and predetermined failsafe control are performed in step S30. It should be noted that the occurrence of a failure in the failure determination is a stricter condition than the preliminary failure determination, so the reliability is high and the possibility that a failure has actually occurred is extremely high.

  On the other hand, when it is determined in step S21 that the vehicle is stopped, the process proceeds to step S31, the flag FRAG1 is reset to zero, and in step S32, when the third speed region is expanded in step S27, This area is initialized to be the area before enlargement.

  If it is determined in step S22 that the flag FRAG1 is not zero, that is, if the preliminary failure determination condition has already been satisfied, the process proceeds to step S28, and a normal failure determination is performed.

  If it is determined in step S23 that the flag FRAG2 is not zero, that is, if the failure determination condition is already satisfied, the process proceeds to step S30, where failure warning and fail-safe control are performed. In other words, if FRAG2 is set to 1 even once in step S29, the flag FRAG2 is not reset to zero in this determination control, and failure warning and fail-safe control are repeated. It will be reset when done.

  On the other hand, when the operation state is not in the third speed region in step S24, the process returns to step S21. Even during the shift, the gear ratio is not stable, so the preliminary failure determination is not performed and the process returns to step S21.

  Further, when the preliminary failure determination condition is not satisfied at step S25, and when the failure determination condition is not satisfied at step S28, both return to step S21.

The step S25 corresponds to the gist of the invention described in claims 5 and 6, and the steps S31 and 32 correspond to the gist of the invention described in claim 1 .

  According to the determination control of the lock-up failure and the gear error failure as described above, the failure determination is first performed by the preliminary failure determination means. Since the preliminary failure determination condition at this time is set so as to make it easy to determine the occurrence of the failure, a failure sign is reliably detected. Then, when a failure sign is detected, the determination area of the control map is expanded and a normal failure determination is performed by the failure determination means. In this failure determination means, failure determination is performed based on normal failure determination conditions, but since the determination area of the control map is expanded, sufficient time for determination is secured and it is possible to prevent overlooking the failure Is done.

  On the other hand, when the driving state is in the low load region, it corresponds to the urban driving mode with high use frequency, and therefore, failure detection with high accuracy is desired. This is because, even if an accurate failure determination is performed in a high load area where a wide area that can be used for the determination can be secured, the frequency of use of this area is low, so failure detection is delayed.

  On the other hand, since the above-described failure determination control is performed when the operation state is in a low load region where the frequency of use is high, an accurate failure determination is performed in the low load region, and a failure occurrence is determined. In such a case, it is possible to quickly take measures such as failure warning and fail-safe control. Also, for example, when the above-described two-stage failure determination is performed only when the throttle opening is equal to or less than a predetermined value, when the throttle opening is equal to or greater than the predetermined value, only regular failure determination needs to be performed. Therefore, it is possible to simplify the control.

  In addition, in the preliminary failure condition, the determination time and / or the determination threshold is set to make it easier to determine the occurrence of the failure than the normal failure determination, so that a sign of the occurrence of the failure is surely detected. . Specifically, in the preliminary failure condition, the determination time is short and the determination threshold is set to the normal value side, so that the occurrence of the failure is determined when an abnormal state is detected even for a short time. In addition, the probability that the detected value exceeds the determination threshold is increased, and it is easy to determine that the state is abnormal.

  On the other hand, in the normal failure determination condition, compared with the preliminary failure determination condition, the determination time is longer and the determination threshold is set to the abnormal value side, so that the abnormal state continues for a long time and / or The occurrence of a failure is determined when the detected value is an obvious abnormality, and when this normal failure determination condition is satisfied, there is a very high possibility that a failure has actually occurred. In addition, if the determination is made with a narrow determination area under such normal failure determination conditions, the possibility of overlooking the failure increases, but the determination area is enlarged, so it is possible to reliably detect the occurrence of the failure. it can.

  On the other hand, when the vehicle is stopped, the extended determination area as a result of satisfying the preliminary failure determination condition is returned to the area before expansion, thereby avoiding long-time driving with the changed control map. Since this is performed particularly when the vehicle is stopped, the uncomfortable feeling caused by suddenly changing the control map during driving is prevented. In the above-described determination of the lock-up failure and the gear error failure, the flag FRAG1 is reset to zero only when the vehicle is stopped, and the determination area of the control map is reset. It may be controlled to reset the occurrence, that is, when the flag FRAG2 is 1. In this case, it is not necessary to use the changed control map because the determination of the occurrence of the failure is confirmed.

  As another embodiment of the present invention, an automatic transmission having a configuration in which a sub-transmission is added to the 4-speed automatic transmission 10 (hereinafter referred to as “main transmission”) shown in the above-described embodiment. The failure determination will be described.

  In the case of such an automatic transmission, for example, when achieving the fifth speed, the main transmission is in the same state as the fourth speed, and the output of the main transmission is shifted by the sub-transmission to achieve the fifth speed. May be configured. Therefore, when the determination of the 5-speed lock-up on failure is made, it can be determined by the same method as the determination of the 4-speed lock-up on failure described above.

  In addition, with such a multi-stage transmission to the fifth speed or the sixth speed, each shift area of the control map becomes narrower. As shown in FIG. 12, in the case of a six-speed automatic transmission, the determination region Z for the third speed, particularly on the low throttle opening side, is narrow. However, when the preliminary failure determination condition is satisfied, the determination region is expanded (Z → Z ′) as shown in FIG. 13 by increasing the speed of the 3-4 shift line. As a result, sufficient time for determination is ensured, and failure determination is performed effectively.

  The present invention relates to a failure detection device for an automatic transmission, and is widely suitable for the technical field of an automatic transmission for a vehicle.

It is a skeleton figure which shows the mechanical structure of the automatic transmission which concerns on embodiment of this invention. FIG. 3 is a hydraulic control circuit diagram of the automatic transmission. It is a control system figure with respect to each solenoid valve with which the hydraulic control circuit was equipped. It is a principal part enlarged view of the hydraulic control circuit which shows the state of 4th speed. It is a principal part enlarged view of the hydraulic control circuit which shows the state of 4-speed lockup. It is a flowchart of 4 speed lockup on failure determination control. It is explanatory drawing of the determination area | region in a control map. It is explanatory drawing at the time of lockup-off area expansion in a control map. It is a flowchart of a 3rd-speed gear error failure determination control. It is explanatory drawing of the determination area | region in a control map. It is explanatory drawing at the time of the 3rd speed area expansion in a control map. It is explanatory drawing of the determination area | region in the control map of a 6-speed automatic transmission. It is explanatory drawing at the time of the 3rd speed area expansion in the control map.

Explanation of symbols

10 Automatic transmission 26 Lock-up clutch 300 Controller

Claims (6)

A failure determination means that is provided in an automatic transmission that performs shift control according to the driving state based on a preset control map, and that performs a failure determination according to a predetermined failure determination condition in a predetermined determination region provided in the control map A fault detection device for an automatic transmission having
Preliminary failure determination in which failure determination is performed according to a preliminary failure determination condition that is set so as to facilitate determination of occurrence of failure with respect to the failure determination condition in a state in which failure determination is not made by the failure determination means Means,
Determination area changing means for enlarging the determination area of the control map when the occurrence of a failure is determined by the preliminary failure determination means,
The failure determination means performs a failure determination in the determination area expanded by the determination area change means when the occurrence of the failure is determined by the preliminary failure determination means ,
When stopping
The preliminary failure determination means returns to a state where a failure occurrence is not determined,
The automatic transmission failure detection device, wherein the determination area changing means changes an enlarged determination area to an area before expansion . In the automatic transmission failure detection device according to claim 1,
The automatic transmission failure detection device, wherein the failure determination means and the preliminary failure determination means determine a lockup on failure in which a lockup clutch of the fluid transmission is abnormally engaged in a lockup off region. In the automatic transmission failure detection device according to claim 1,
The automatic transmission failure detection device, wherein the failure determination means and the preliminary failure determination means determine a gear error failure in which a gear ratio deviates from a gear ratio of a target gear. In the automatic transmission failure detection device according to any one of claims 1 to 3,
The failure detection device for an automatic transmission, wherein the failure determination means and the preliminary failure determination means perform failure determination when the operating state is in a low load region. In the automatic transmission failure detection device according to any one of claims 1 to 4,
The failure determination condition is set to determine the occurrence of a failure when the duration of the abnormal state exceeds a predetermined determination time,
The automatic transmission failure detection apparatus according to claim 1, wherein the determination time of the preliminary failure determination condition is set to be shorter than the predetermined determination time. In the automatic transmission failure detection device according to any one of claims 1 to 4,
The failure determination condition is set so as to determine a failure occurrence by comparing a detection value with a predetermined determination threshold,
The automatic transmission failure detection device according to claim 1, wherein a determination threshold value of the preliminary failure determination condition is set to a normal value side with respect to the predetermined determination threshold value.

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