JP2006112534A - Shift control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift control device for an automatic transmission, preventing decline in power performance of a vehicle even when gear shift of a main transmission becomes impossible and the main transmission remains shifted to a high-speed stage side and preventing decline in over-speed and reduction in a range of speed capable of travelling even when the main transmission remains shifted to a low-speed stage side. <P>SOLUTION: The shift control device for the automatic transmission with an auxiliary transmission 20 having a plurality of shift stages connected to an output side of an engine 15 is provided with a shift control means 11 controlling a gear ratio of the main transmission 14 and the auxiliary transmission 20 in accordance with an operating condition of the vehicle by input of information (a) on the operating condition of the vehicle on which the main transmission 14 is mounted; and an auxiliary transmission control change means 21 changing shift control of the auxiliary transmission 20 to a direction in which engine 15 speed increases when the operation of the main transmission 14 is stopped at a gear ratio in the high-speed stage, and changing shift control of the auxiliary transmission 20 to a direction in which engine 15 speed decreases when the operation of the main transmission 14 is stopped at a gear ratio in the low-speed stage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control device for an automatic transmission including a sub-transmission having a multiple-stage transmission mechanism with a prime mover.

  2. Description of the Related Art Conventionally, an automatic transmission (main transmission) having a sub-transmission that switches between a high speed stage (High) and a low speed stage (Low) instead of a torque converter on the input side, that is, on the output side of a prime mover (engine) ) Is known (see Patent Document 1). This sub-transmission has a configuration in which the high speed stage is selected when the high speed stage selection clutch is engaged, and the low speed stage is selected by the one-way clutch acting when the high speed stage selection clutch is released.

As a result, the sub-transmission is set to the low-speed stage selection state, which is the deceleration stage, at the time of start, and the friction element that changes the main transmission of the rear stage of the sub-transmission from the neutral state to the power transmission state is controlled to be engaged. Is eliminated, and the reduction in transmission efficiency of the automatic transmission caused by using the torque converter can be eliminated.
JP 2002-340163 A

  However, if the automatic transmission becomes unable to shift due to a malfunction or the like and remains switched to the high speed stage, the power performance of the vehicle will be reduced, and conversely remains switched to the low speed stage. In this case, the so-called overrev vehicle speed becomes low and the speed range in which the vehicle can travel is narrowed.

  It is an object of the present invention to provide an overspeed vehicle speed even when the automatic transmission is switched to the high speed stage side without being shifted to the high speed stage side even when the automatic transmission is switched to the low speed stage side without being deteriorated. It is an object of the present invention to provide a shift control device for an automatic transmission that does not decrease the speed range in which travel is possible.

  To achieve the above object, a shift control apparatus for an automatic transmission according to the present invention is the shift control apparatus for an automatic transmission including a sub-transmission having a plurality of shift stages connected to the output side of the prime mover. A shift control means for controlling a gear ratio of the main transmission and the sub-transmission according to the driving state of the vehicle by inputting information on the driving state of the vehicle on which the automatic transmission is mounted, and the main transmission When the operation is stopped at the gear ratio on the high speed side, the shift control of the sub-transmission is changed to a direction in which the rotational speed of the prime mover is increased, and when the main transmission is stopped at the gear ratio on the low speed stage side, Sub-transmission control change means for changing the shift control of the sub-transmission in a direction in which the rotational speed of the prime mover decreases.

  According to the present invention, when the automatic transmission stops operating at the high speed side gear ratio, the speed change control of the sub-transmission is changed to increase the rotational speed of the prime mover and operates at the low speed side gear ratio. When stopped, the shift control of the sub-transmission is changed in a direction that reduces the rotational speed of the prime mover, so the automatic transmission becomes unable to shift and stops operating while being switched to the high speed stage. However, it is possible to prevent the power performance of the vehicle from deteriorating, and even if the operation is stopped while switching to the low speed stage side, the overrev vehicle speed is prevented from being lowered and the speed range within which the vehicle can run Can be prevented from becoming narrow.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a shift control apparatus for an automatic transmission according to an embodiment of the present invention. As shown in FIG. 1, the shift control device 10 for an automatic transmission has a shift control means 11 and a sub-transmission control change means 12, and the sub-transmission control change means 12 has an operation stop state determination means 13. is doing. The shift control means 11 performs shift control of the automatic transmission (main transmission) 14 including the auxiliary transmission 20.

  The sub-transmission 20 arranged in the preceding stage, which is the input side of the main transmission 14, is arranged in series with the main transmission 14 on the output side of the engine (prime mover) 15 that is a driving force source. The main transmission 14 is a continuously variable transmission in which the gear ratio continuously changes in a stepless manner, or a stepped transmission in which the gear ratio changes in a stepwise manner with at least two speed steps of a low speed step and a high speed step. Any of these may be used. The sub-transmission 20 has two speed stages, a high speed stage (High) and a low speed stage (Low), and can be switched to either one.

  The shift control means 11 outputs the shift control information b based on the driving state of the vehicle in response to the input of the information a regarding the driving state of the vehicle on which the main transmission 14 is mounted, so that the main transmission 14 and the auxiliary transmission 20 Control the gear ratio. The sub-transmission control change means 12 outputs the shift control change information c when the main transmission 14 is stopped due to a failure, for example, and when the main transmission 14 is stopped at the high speed side gear ratio, When the control is changed in the direction in which the rotational speed of the engine 15 increases and the operation is stopped at the low speed gear ratio, the shift control of the sub-transmission 20 is changed in the direction in which the rotational speed of the engine 15 decreases. The operation stop state determination means 13 determines whether or not the main transmission 14 is in an operation stop state, and detects the operation stop state of the main transmission 14.

  The sub-transmission control changing means 12 performs shift control of the sub-transmission 20 for changing the engine speed in the increasing direction or the decreasing direction based on the engine speed, and the engine speed and the throttle opening degree. Perform based on (accelerator opening). When the shift control of the sub-transmission 20 is performed based on the engine speed and the throttle opening, the high gear ratio (low speed stage) is widened when the throttle opening is small, and the low shift is performed when the throttle opening is large. Widen the ratio (high speed stage) area.

  FIG. 2 is a schematic diagram illustrating a transmission path of an automatic transmission including the auxiliary transmission of FIG. As shown in FIG. 2, the main transmission 14 is a toroidal-type continuously variable transmission including a sub-transmission 20, and the rotation from the engine 15 moves forward and backward through the sub-transmission 20 and the transmission input shaft 16. This is transmitted to the switching mechanism 17.

  Two toroidal transmission units 18 and 19 on the front side and the rear side are installed at the rear stage of the forward / reverse switching mechanism 17. Each of these toroidal transmission units 18 and 19 has input disks 18a and 19a, and output disks 18b and 19b arranged coaxially and opposed thereto. The output disks 18b and 19b are coaxially arranged so as to be back to back, and a pair of power rollers 18c and 19c are provided between the front input / output disks 18a and 18b and the rear input / output disks 19a and 19b. Is interposed.

  When the two output disks 18b and 19b are arranged, the input disks 18a and 19a are rotatably engaged with the main shaft 30 so that the rotation from the forward / reverse switching mechanism 17 is input in common. Supported. The output disks 18 b and 19 b are integrally coupled to each other via a hollow output shaft 31, and an output gear 32 is fixed on the hollow output shaft 31. The output gear 32 meshes with a counter gear 34 attached to the front end of the countershaft 33, and the rear end of the countershaft 33 passes through an output gear set 35 to a transmission output shaft 36 coaxially arranged behind the main shaft 30. Drive coupled.

  The rotation from the forward / reverse switching mechanism 17 is commonly transmitted to the input disks 18a and 19a, and the rotation of the input disks 18a and 19a is transmitted to the output disks 18b and 19b via the corresponding power rollers 18c and 19c. Reach. A transmission output shaft 36 is sequentially passed through an output gear 32 that rotates in common with the rotation of the output disks 18b and 19b, a counter gear 34 that meshes with the output gear 32, a counter shaft 33, and an output gear set 35. , The rotation from the forward / reverse switching mechanism 17 is taken out.

  When shifting, the power rollers 18c and 19c are synchronized with each other from the neutral position where the rotation axis of the power rollers 18c and 19c intersects the rotation axis of the front input / output disks 18a and 18b and the rear input / output disks 19a and 19b. When offset (in the same speed change direction), the power rollers 18c and 19c are tilted in the same phase in synchronism around the swing axis perpendicular to the rotation axis of the power roller by the component force during rotation. Thereby, the contact locus arc diameter of each power roller 18c, 19c with respect to the front-side input / output disks 18a, 18b and the rear-side input / output disks 19a, 19b continuously changes, and a predetermined continuously variable transmission can be performed. .

  When the gear ratio becomes the command gear ratio, the power rollers 18c and 19c are returned to the initial stroke position where the offset is 0, so that the self-tilt of the power rollers 18c and 19c is not performed and the command gear ratio is set. Can keep.

  The auxiliary transmission 20 is configured by incorporating the following components in a housing 21, and the housing 21 is coupled to a crankshaft of the engine 15 via a drive plate 22. In other words, the input shaft (input shaft of the automatic transmission) 16 of the forward / reverse switching mechanism 17 constituting the automatic transmission together with the toroidal transmission units 18 and 19 is inserted into the housing 21 and is simply placed on the insertion end of the input shaft 16. The planetary gear set 23 is attached. The simple planetary gear set 23 includes a sun gear 23s, a ring gear 23r, a plurality of pinions 23p meshing with both the gears 23s and 23r, and a carrier 23c that rotatably supports the pinion 23p via a pinion shaft 23t. It is normal.

  The carrier 23c of the simple planetary gear set 23 is drive-coupled to the input shaft 16 and also to the clutch hub 24h of the high-speed stage selection clutch 24. The ring gear 23 r of the simple planetary gear set 23 is placed on the hollow fixed shaft 26 via the one-way clutch 25 so that it cannot rotate in the direction opposite to the rotation of the engine 15. The one-way clutch 25 fixes the inner race to the hollow fixed shaft 26 (transmission case) and connects the outer race to the ring gear 23r, and is positioned between the hollow fixed shaft 26 and the ring gear 23r.

  In addition to the clutch hub 24h, the high-speed gear selection clutch 24 includes a clutch drum 24d rotatably accommodated in the housing 21. The clutch drum 24d is drivingly coupled to the housing 21 via a high-speed gear damper 27. Further, the clutch drum 24 d is drivingly coupled to the sun gear 23 s of the simple planetary gear set 23 via the low-speed stage damper 28.

  The high-speed stage selection clutch 24 includes a clutch piston (not shown) fitted in the clutch drum 24d so as to be slidable in the axial direction. When this piston is hydraulically stroked to the simple planetary gear set 23 side, it is engaged. Thus, the clutch drum 24d and the clutch hub 24h are coupled. At this time, the rotation from the high speed stage damper 27 is transmitted to the input shaft 16 as it is (high speed: directly coupled stage selected state) via the carrier 23c without passing through the low speed stage damper 28.

  On the other hand, when the hydraulic pressure is not applied to the clutch piston and the high speed stage selection clutch 24 is released (see FIG. 2), the rotation from the high speed stage damper 27 passes through the low speed stage damper 28 and the simple planetary gear set 23. The sun gear 23s is reached. Here, in the sun gear 23s, the high-speed stage selection clutch 24 is released, and the one-way clutch 25 prevents the ring gear 23r from rotating in the reverse direction to the engine 15, so the carrier 23c is decelerated in the same direction. Rotation drive is performed, whereby power is transmitted to the input shaft 16 in a low speed stage selected state.

  The damper characteristic of the high speed stage damper 27 is set to a characteristic required in the high speed stage selection state (direct connection stage selection state), and the low speed stage damper 28 is set to a characteristic required in the low speed stage selection state. Keep it.

  Here, the actual configuration of the forward / reverse switching mechanism 17 will be supplementarily described. The forward / reverse switching mechanism 17 includes a simple planetary gear set 17c in addition to the forward clutch 17a and the reverse brake 17b. When the forward clutch 17a is engaged by hydraulic pressure, the sun gear 17d of the simple planetary gear set 17c and the ring gear 17e are coupled, and the simple planetary gear set 17c is brought into an interlocking state in which all the rotating members rotate integrally. Then, the rotation from the input shaft 16 is transmitted to the subsequent toroidal transmission units 18 and 19 as it is, thereby enabling forward traveling in the D range.

  Further, when the reverse brake 17b is hydraulically engaged, the carrier 17f of the simple planetary gear set 17c is fixed, the rotation from the input shaft 16 is decelerated, and the reverse rotation to the toroidal transmission units 18 and 19 downstream from the sun gear 17d. By transmitting, it enables reverse travel in the R range.

  For this reason, when parking in the P and N ranges, both the forward clutch 17a and the reverse brake 17b are released and the rotation from the input shaft 16 is not transmitted to the subsequent toroidal transmission units 18 and 19, thereby Make it possible to stop.

  The above-described engagement / release control of the forward clutch 17a and the reverse brake 17b of the forward / reverse switching mechanism 17, the shift control of the toroidal transmission units 18 and 19, and the engagement / release control of the high-speed stage selection clutch 24 in the sub-transmission 20, respectively. This is performed by the transmission controller 38 via the control valve body 37.

  The transmission controller 38 includes information from the engine rotation sensor 39 that detects the engine speed, information from the throttle opening sensor 40 that detects the throttle opening TVO of the engine 15, and when the accelerator pedal is not depressed (No operation). Information from the idle switch 41 that is turned on at the time of detection), the information from the brake switch 42 that is turned on when the brake pedal is depressed (during operation) and detects the braking state, and the vehicle speed at which the vehicle speed VSP is detected. Information from the sensor 43 is input.

  As described above, the sub-transmission 20 decelerates the rotation from the engine 15 and inputs it to the main transmission 14, and the direct connection stage (high-speed stage) that directly inputs the rotation from the engine 15 to the main transmission 14. have. Next, the shift control by the shift control device 10 in the automatic transmission including the sub-transmission 20 and the main transmission 14 will be described. The shift control device 10 is configured mainly by a microcomputer, and executes a shift control program (not shown) stored in a storage medium (Read Only Memory: ROM) to input information a regarding the driving state of the vehicle. The corresponding shift control is performed.

  FIG. 3 is a flowchart showing a flow of a first shift process by the shift control device of FIG. FIG. 4 is a sub-transmission conversion map for when the main transmission is abnormal, and FIG. 5 is a sub-transmission conversion map for when the main transmission is normal. In each map, 1 is a low speed stage and 2 is a high speed stage.

  As shown in FIG. 3, first, the shift control device 10 detects the vehicle speed VSP and the throttle opening TVO from the input information a regarding the driving state of the vehicle (step S101). After the detection, the main transmission 14 is deactivated. It is determined whether or not it is in a state (step S102).

  As a result of the determination, if the main transmission 14 is in the operation stop state (yes), the current gear ratio of the main transmission 14 in the gear shift operation stop state is estimated (step S103), and the vehicle speed VSP and the throttle opening TVO are The optimum gear position of the sub-transmission 20 is determined (step S104) using the sub-transmission shift map (see FIG. 4) for when the main transmission is abnormal based on the relationship. On the other hand, when the main transmission 14 is not in the operation stop state (no), the sub-transmission is transmitted using the sub-transmission shift map for normal transmission (see FIG. 5) based on the relationship between the vehicle speed VSP and the throttle opening TVO. 20 optimum gear positions are determined (step S105).

  The sub-transmission shift map for main transmission abnormality used for determining the gear position of the sub-transmission 20 is a map for high-speed (High) side stop and a map for low-speed (Low) side stop. Types are prepared (see FIG. 4). When the main transmission 14 is stopped at the high speed (High) side, the map for the high speed (High) side stop is displayed, and the main transmission 14 is at the low speed (Low). When the operation is stopped on the) side, the low speed (Low) side stop map is used. In other words, when the main transmission 14 is in an operation stop state due to, for example, a failure or the like, the shift map of the sub-transmission 20 is stopped at the high speed (High) side in accordance with the fixed gear ratio of the main transmission 14. Switch to either time or low speed (Low) side stop.

  Next, it is determined whether or not the current shift speed of the sub-transmission 20 is the determined shift speed (current shift speed = determined shift speed) (step S106), and the shift speed determined by the current shift speed is determined. If (yes), the current gear position is maintained (step S107), and the process is terminated. On the other hand, if the current gear position is not the determined gear position (no), the sub-transmission 20 is shifted to the determined gear position (step S108), and then the process ends.

  FIG. 6 is a flowchart showing a flow of a second shift process by the shift control device of FIG. FIG. 7 is an auxiliary transmission conversion map for when the main transmission is abnormal, and FIG. 8 is an auxiliary transmission conversion map for when the main transmission is normal. In each map, 1 is a low speed stage and 2 is a high speed stage.

  As shown in FIG. 6, first, the shift control device 10 detects the vehicle speed VSP, the throttle opening TVO, and the engine speed from the input information a regarding the driving state of the vehicle (step S201). It is determined whether the machine 14 is in an operation stop state (step S202).

  As a result of the determination, when the main transmission 14 is in an operation stop state (yes), the main transmission abnormality sub-transmission shift map (see FIG. 7) based on the relationship between the engine speed and the throttle opening TVO is used. Then, the optimum gear position of the auxiliary transmission 20 is determined (step S203). On the other hand, when the main transmission 14 is not in the operation stop state (no), the sub-shift is performed using the sub-transmission map for normal transmission (see FIG. 8) based on the relationship between the vehicle speed VSP and the throttle opening TVO. The optimum gear position of the machine 20 is determined (step S204).

  That is, for example, when the main transmission 14 is in an operation stop state due to a failure or the like, the shift map of the sub-transmission 20 is used for normal time (normal time) in accordance with the fixed gear ratio of the main transmission 14. The shift map based on the relationship between the vehicle speed VSP and the throttle opening TVO is switched to the shift map based on the relationship between the engine speed for an abnormality and the throttle opening TVO.

  Next, it is determined whether or not the current shift speed of the sub-transmission 20 is the determined shift speed (current shift speed = determined shift speed) (step S205), and the shift speed determined by the current shift speed is determined. If (yes), the current gear position is maintained (step S206), and the process is terminated. On the other hand, if the current shift speed is not the determined shift speed (no), the sub-transmission 20 is shifted to the determined shift speed (step S207), and then the process ends.

  As described above, the shift control device 10 for the automatic transmission according to the present invention controls the shift control of the sub-transmission 20 when the main transmission 14 is stopped at a high gear ratio due to, for example, a failure. When the engine speed is changed to increase and the operation is stopped at the low speed gear ratio, the speed change control of the auxiliary speed ratio 20 is changed to decrease the engine speed. As a result, even if the main transmission 14 becomes incapable of shifting and stops operating while being switched to the high speed stage, it is possible to prevent the power performance of the vehicle from deteriorating, and to the low speed stage. Even when the operation is stopped while being switched, it is possible to prevent the overrev vehicle speed from being lowered and to prevent the speed range in which the vehicle can travel from becoming narrow.

  Further, in this shift control device 10, the sub-transmission control change means 12 performs shift control of the sub-transmission 20 based on the engine speed when the main transmission 14 is in the operation stop state. That is, by shifting the sub-transmission 20 based on the engine speed, the stop gear ratio estimation logic when the main transmission 14 is stopped is unnecessary, and the sub-transmission shift for the main transmission abnormality There is no need to prepare a plurality of maps for each stop gear ratio.

  The sub-transmission control changing means 12 performs shift control of the sub-transmission 20 based on the engine speed and the throttle opening TVO (accelerator opening). The area of the transmission 20 is set to be wide, and when the throttle opening TVO is large, the area of the low gear ratio (the high speed stage of the auxiliary transmission 20) is widened. As a result, when the opening degree is large, that is, when the driving force requirement is large, the driving force can be extracted by increasing the engine speed, and when the opening degree is small, that is, when the driving force requirement is small, It is possible to prevent the engine speed from becoming higher than necessary.

1 is a block diagram showing a schematic configuration of a shift control device for an automatic transmission according to an embodiment of the present invention. FIG. FIG. 2 is a schematic diagram showing a transmission path of an automatic transmission provided with the auxiliary transmission of FIG. It is a flowchart which shows the flow of the 1st shift process by the shift control apparatus of FIG. It is a subtransmission conversion map for main transmission abnormality. It is a subtransmission conversion map for normal transmission of the main transmission. 6 is a flowchart showing a flow of second shift processing by the shift control device of FIG. 1. It is a subtransmission conversion map for main transmission abnormality. It is a subtransmission conversion map for normal transmission of the main transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shift control apparatus 11 Shift control means 12 Subtransmission control change means 13 Operation stop state judgment means 14 Main transmission 15 Engine 16 Transmission input shaft 17 Forward / reverse switching mechanism 17a Forward clutch 17b Reverse brake 17c Simple planetary gear set 17d Sun gear 17e ring gear 17f carrier 18, 19 toroidal transmission unit 18a, 19a input disk 18b, 19b output disk 18c, 19c power roller 20 sub-transmission 21 housing 22 drive plate 23 simple planetary gear set 23c carrier 23p pinion 23r ring gear 23s sun gear 23t pinion shaft 24 High-speed gear selection clutch 24d Clutch drum 24h Clutch hub 25 One-way clutch 26 Hollow fixed shaft 27 High-speed gear damper 28 Low-speed gear Damper 30 Main shaft 31 Hollow output shaft 32 Output gear 33 Counter shaft 34 Counter gear 35 Output gear set 36 Transmission output shaft 37 Control valve body 38 Transmission controller 39 Engine rotation sensor 40 Throttle opening sensor 41 Idle switch 42 Brake switch 43 Vehicle speed Sensor a Information related to driving state of vehicle b Shift control information c Shift control change information

Claims (3)

In a shift control device for an automatic transmission comprising a sub-transmission having a plurality of shift stages connected to the output side of a prime mover,
Shift control means for controlling a gear ratio of the automatic transmission and the sub-transmission according to the driving state of the vehicle by inputting information on the driving state of the vehicle on which the automatic transmission is mounted;
When the automatic transmission stops operating at the gear ratio on the high speed side, the shift control of the sub-transmission is changed to a direction in which the rotational speed of the prime mover increases, and the automatic transmission changes at the gear ratio on the low speed stage side. A shift control apparatus for an automatic transmission, comprising: a sub-transmission control change means that changes the shift control of the sub-transmission in a direction in which the rotational speed of the prime mover decreases when the operation is stopped.   2. The shift control device for an automatic transmission according to claim 1, wherein the sub-transmission control change unit performs conversion control of the sub-transmission based on a rotation speed of the prime mover when the operation of the automatic transmission is stopped.   The sub-transmission control changing means performs shift control of the sub-transmission based on the number of rotations of the prime mover and the throttle opening. When the throttle opening is small, the high gear ratio region is widened, and the throttle opening is 3. The shift control device for an automatic transmission according to claim 1, wherein when it is large, the region of the low gear ratio is widened.

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