JP2014214787A - Control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly switch an allowable rotation direction of a two-way clutch (TWC) to a direction in which a forward stage is established from a direction in which a rearward stage is established, in an automatic transmission which switches between the forward stage and the rearward stage by switching the allowable rotation directions of the TWC which can switch the directions for allowing rotation.SOLUTION: An ECU 30 detects a shift range position of an automatic transmission 10, and detects an allowable rotation direction of a TWC 22. When a neutral range position is detected as the shift range position, and a direction for establishing a rearward stage is detected as the allowable rotation direction of the TWC 22, the allowable rotation direction of the TWC 22 is switched to a direction in which the rearward stage is established.

Description

  The present invention relates to control of an automatic transmission using a planetary gear mechanism.

  In automatic transmissions for automobiles, in order to improve running performance and driving performance, the number of shift stages is increasing. An automatic transmission generally includes a planetary gear mechanism, and an engagement mechanism such as a one-way clutch (hereinafter referred to as OWC), a two-way clutch (hereinafter referred to as TWC), a brake, and a clutch, and the power transmission path is switched by the engagement mechanism. Each gear stage is realized. For this reason, the number of gears can be increased by increasing the number of planetary gear mechanisms and engagement mechanisms (see Patent Document 1).

  In an automatic transmission using TWC, with the TWC switched to the reverse gear side, the vehicle descends at the neutral range and accelerates, and when in-gearing from the neutral range to the second gear or higher, an interlock is generated in the automatic transmission. The wheel may be fixed.

JP 2012-097864 A JP 2012-117552 JP JP 2012-154425 A

  The present invention relates to an automatic transmission that switches a front speed and a reverse speed by switching a permissible rotation direction of a two-way clutch (TWC) that can switch a permissible rotation direction. The purpose is to switch appropriately in the direction of establishing the stage.

  The present invention has the following configuration as one means for achieving the above object.

  According to the first aspect of the present invention, the driving force from the driving source (20) is shifted from a plurality of shift speeds to a predetermined shift speed according to the traveling state of the vehicle, and the shifted driving power is transmitted to the drive wheels of the vehicle An automatic transmission (10) that connects a plurality of planetary gear mechanisms (P1-P4) having rotating elements such as a sun gear, a carrier, and a ring gear and the rotating elements of the planetary gear mechanism. A plurality of engagement mechanisms for fixing, and the shift stage is established by a combination of engagements of the plurality of engagement mechanisms, wherein one of the plurality of engagement mechanisms is a rotating element of the plurality of planetary gear mechanisms. This is a mechanical engagement mechanism (F1) that allows switching of the allowable rotation direction that allows one rotation direction, and the other engagement mechanisms are friction engagement mechanisms (C1-C3, B1-B3), The mechanical engagement mechanism so as to switch a permissible rotational direction of the mechanical engagement mechanism between a step and a reverse step. In the automatic transmission control device (30) for operating the automatic transmission, position detection means (30) for detecting a shift range position of the automatic transmission, and rotation direction detection means for detecting an allowable rotation direction of the mechanical engagement mechanism (30), and when the neutral range position is detected as the shift range position and the direction of establishing the reverse gear is detected as the allowable rotation direction of the mechanical engagement mechanism, the mechanical engagement mechanism The allowable rotation direction is switched to the direction in which the forward speed is established.

  The invention of claim 2 further comprises vehicle speed detection means (33) for detecting the vehicle speed of the vehicle, and the direction in which the mechanical engagement mechanism establishes the forward gear when a vehicle speed equal to or higher than a predetermined speed is detected. Switch to.

  In the invention of claim 3, a neutral range position is detected as the shift range position, a direction for establishing the reverse speed is detected as an allowable rotation direction of the mechanical engagement mechanism, and a vehicle speed equal to or higher than the predetermined speed is detected. When the signal for shifting the shift range position to the forward gear is input, the forward gear is detected until it is detected that the allowable rotation direction of the mechanical engagement mechanism is switched to the direction for establishing the forward gear. Wait for shift to.

  In the invention of claim 4, when the allowable rotation direction of the mechanical engagement mechanism cannot be switched from the direction of establishing the reverse gear to the direction of establishing the forward gear, the allowable rotation direction of the mechanical engagement mechanism is Even in the direction of establishing the reverse gear, a combination of engagement of the engagement mechanisms capable of establishing a predetermined forward gear is executed.

  The invention according to claim 5 prohibits the establishment of a gear position when the predetermined forward speed is established and it is determined that the internal combustion engine as the drive source exceeds a predetermined speed.

  According to the invention of claim 1, in the automatic transmission that switches between the forward speed and the reverse speed by switching the allowable rotation direction of the two-way clutch (TWC) capable of switching the direction in which the rotation is allowed, the allowable rotation direction of the TWC is reversed. It is possible to appropriately switch from the direction in which the stage is established to the direction in which the forward stage is established.

  According to the invention of claim 2, the mechanical engagement mechanism can be switched reliably before the vehicle speed increases at the neutral range position and the mechanical engagement mechanism cannot be switched. Can prevent overload input.

  According to the invention of claim 3, interlock can be prevented.

  According to the invention of claim 4, it is possible to ensure the running ability at the time of failure of the TWC.

  According to the invention of claim 5, it is possible to protect the internal combustion engine and prevent sudden deceleration.

The skeleton figure of the automatic transmission of an Example. The engagement table of the engagement mechanism in an automatic transmission. The figure which shows the engagement state of TWC. A normal speed diagram of an automatic transmission. The speed diagram for demonstrating generation | occurrence | production of an interlock. Sectional drawing which shows an example of TWC. The block diagram which shows the system structural example of an automatic transmission. The flowchart explaining TWC switching control. 6 is a flowchart for explaining shift range position switching control in consideration of a state in which TWC cannot be switched. The speed diagram of the automatic transmission which shows a 2.5-speed stage.

  Hereinafter, control of an automatic transmission according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Automatic transmission]
Skeleton Diagram FIG. 1 is a skeleton diagram of the automatic transmission 10 of the embodiment. The automatic transmission 10 is rotated coaxially with the input shaft 11 by an input shaft 11 rotatably supported in a casing member 12 constituting the transmission case, and a support member 12a supported by the casing member 12. An output member 13 that is freely supported is provided.

  A driving force is input to the input shaft 11 from a driving source (not shown) such as an internal combustion engine or an electric motor, and the input shaft 11 is rotated by the driving force. A starting device can be provided between the input shaft 11 and the drive source, and by providing the starting device, it is possible to alleviate a shift shock. Examples of the starting device include a clutch-type starting device (such as a single-plate clutch and a multi-plate clutch) and a fluid coupling-type starting device (such as a torque converter).

  The output member 13 includes an output gear concentric with the input shaft 11, and the rotation of the input shaft 11 is shifted by a transmission mechanism described below and transmitted to the output member 13. The rotation of the output member 13 is transmitted to the drive wheels via a differential gear device (not shown), for example.

  The automatic transmission 10 includes first to fourth planetary gear mechanisms P1 to P4 as a speed change mechanism and a plurality of engagement mechanisms. The plurality of engagement mechanisms include clutches C1 to C3 and brakes B1 to B3 as friction engagement mechanisms, and a two-way clutch (TWC) F1 as a mechanical engagement mechanism. The planetary gear mechanisms P1 to P4 include a sun gear S, a ring gear R, a pinion gear P, and a carrier C that supports the pinion gear as rotating elements, and are arranged coaxially with the input shaft 11.

  The engaging mechanism is releasably connected between the predetermined rotating elements of the planetary gear mechanisms P1 to P4, between the input shaft 11 and the predetermined rotating element, or between the predetermined rotating element and the casing member 12. To do. By switching the state of each engagement mechanism between the connected state and the disconnected state, the power transmission path from the input shaft 11 to the output member 13 can be switched, and a plurality of shift speeds are realized.

  In this embodiment, the planetary gear mechanisms P1 to P4 are all single-pinion type planetary gear mechanisms. Examples of the frictional engagement mechanism include a dry or wet single-plate clutch, a dry or wet multi-plate clutch, and the TWC described in FIG.

Engagement Mechanism FIG. 2 is an engagement table of the engagement mechanism in the automatic transmission 10. In FIG. 2, when the symbol ○ is attached to the row of the brake Bn and the clutch Cn, this indicates that the engagement mechanism is in a connected state, and when the symbol is not indicated, the engagement mechanism is in a disconnected state. Show. Further, the symbol R described in the column of TWC F1 indicates that the TWC is in a connected state as a two-way clutch. Similarly, the symbol F indicates that the TWC is engaged as a one-way clutch, and the symbol (F) indicates that the TWC is deactivated by the one-way clutch.

  FIG. 3 shows the engaged state of TWC F1. In the reverse speed RVS1, TWC F1 is in the connected state R, and the carrier C of the planetary gear mechanism P2 is in the locked state both when the wheels are driven and not driven (engine brake). At the first speed 1st, TWC F1 is in the connected state F, the carrier C of the planetary gear mechanism P2 is locked when the wheels are driven, and the carrier C of the planetary gear mechanism P2 is free during idle driving. At the second speed or higher and 2nd-10th, TWC F1 is in the disconnected state (F), and the carrier C of the planetary gear mechanism P2 is in the free state.

  As described above, the automatic transmission 10 according to the embodiment realizes the forward 10 speeds and the reverse speed RVS1 by connecting three of the seven engagement mechanisms at each speed. Note that the 2.5-speed stage shown in FIG. 2 is not a shift stage used during normal travel, but is a shift stage used during a failure, as will be described in detail later.

Speed Diagram FIG. 4 is a normal speed diagram of the automatic transmission 10. On the other hand, FIG. 5 is a velocity diagram for explaining the occurrence of the interlock. The thick solid line shown in FIG. 5 shows the speed diagram of the second gear when the TWC F1 is in the connected state F or the disconnected state (F). In this case, no interlock is generated.

  A thick broken line 51 shown in FIG. 4 indicates the occurrence of an interlock when the TWC F1 is in the connected state R. In other words, when the second-speed engagement mechanism combination (brakes B1, B2, and clutch C2 are connected), TWC F1 is in the connected state R, so the carrier C2 of the planetary gear mechanism P2 is fixed, and the A lock occurs. Such a situation occurs, for example, when the vehicle is moved backward and then accelerated by descending a slope in the neutral range and in-gearing from the neutral range to the second gear or higher.

● TWC
In order to prevent the above-mentioned interlock, it is possible to switch the TWC F1 from the connected state R to the connected state F or the disconnected state (F) before in-gearing to the second gear or higher, but there are cases where switching cannot be performed, This point will be described. Hereinafter, the state R in which the allowable rotation direction of the TWC F1 is in the direction of establishing the reverse gear is referred to as `` reverse driving state R '', and the state F in which the allowable rotation direction of the TWC F1 is in the direction of establishing the forward gear is described. The disconnected state (F) may be referred to as “forward state F”.

  FIG. 6 is a cross-sectional view showing an example of TWC. The TWC includes an inner ring TW1 coupled to the carrier C, an outer ring TW2 that is spaced apart in the radial direction of the inner ring TW1, and a holding ring TW3 that is disposed between the inner ring TW1 and the outer ring TW2. Is provided. The outer ring TW2 is connected to the casing member 12. A plurality of cam surfaces TW1a are formed on the outer peripheral surface of the inner ring TW1. The retaining ring TW3 is provided with a plurality of cutout holes TW3a corresponding to the cam surface TW1a. A roller TW4 is accommodated in the cutout hole TW3a.

  The TWC includes first and second electromagnetic clutches not shown. When the first electromagnetic clutch is energized, the outer ring TW2 and the holding ring TW3 are connected. When the first electromagnetic clutch is not energized, the holding ring TW3 is rotatable relative to the inner ring TW1 and the outer ring TW2. The diameter of the roller TW4 is such that when the roller TW4 is at the center of the cam surface TW1a, the gap A is opened (FIG. 6 (a)), and when the roller TW4 is at the end of the cam surface TW1a, the inner ring TW1 and the outer ring TW4 It is set so as to come into contact with the ring TW2 (FIG. 6 (b)).

  Therefore, when the first electromagnetic clutch is not energized, the holding ring TW3 can freely rotate, and the roller TW4 continues to be positioned at the center of the cam surface TW1a as shown in FIG. Will be possible.

  On the other hand, when the first electromagnetic clutch is energized, the holding ring TW3 is fixed to the casing member 12 via the outer ring TW2. In this case, even if the inner ring TW1 tries to rotate forward or backward, the roller TW4 is positioned at the end of the cam surface TW1a because the holding ring TW3 is fixed as shown in FIG. 6 (b). . Accordingly, the roller TW4 is sandwiched between the cam surface TW1a and the inner peripheral surface of the outer ring TW2, and the rotation of the inner ring TW1 is prevented. That is, the TWC is locked.

  The second electromagnetic clutch is configured to freely switch the next state. The first state is a state in which the notch hole TW3a is located at one end of the cam surface TW1a, and is a connected state of the holding ring TW3 and the inner ring TW1 (FIG. 6 (b)). The second state is a state in which the notch hole TW3a is located at the other end of the cam surface TW1a (not shown), and the holding ring TW3 and the inner ring TW1 are connected. The third state is a disconnected state of the holding ring TW3 and the inner ring TW1.

  When the clockwise direction in FIG. 6 is the reverse direction, the TWC releases the connection of the outer ring TW2 and the holding ring TW3 by deenergizing the first electromagnetic clutch, and puts the second electromagnetic clutch in the first state. It will be in the state which prevents reverse rotation by.

  In a state where the shift range position is in the neutral range position and the vehicle speed is present, that is, in a situation where the vehicle is moving forward by turning from the foot axis on a downhill or the like, the TWC F1 is loaded with the planetary gear mechanism P2 as a load. Driven by the elements constituting the sun gear S2 (element inertia, clutch friction of the carrier C2, etc.) is added. The torque for driving the element is small at low vehicle speeds, but the higher the vehicle speed, the greater the differential rotation of the carrier C2, the greater the friction of the carrier C2, and it becomes difficult to switch the TWC F1 from the reverse state R to the forward state F. . Therefore, the TWC F1 is switched from the reverse state R to the forward state F at a low vehicle speed before the high vehicle speed is reached.

[System configuration]
FIG. 7 is a block diagram showing a system configuration example of the automatic transmission.

  The electronic control unit (ECU) 30 controls the rotation of the engine 20 according to the operation of the accelerator pedal 31. Further, the ECU 30 controls the shift range position of the automatic transmission 10 based on the operation of the shift lever 32. The control of the shift range position also includes control of switching the reverse state R / forward state F of the TWC 22 by operating the electromagnetic clutches 22a and 22b corresponding to the above-described first and second electromagnetic clutches of the TWC 22 (TWC F1). included.

  The ECU 30 inputs the following information in order to perform the TWC switching control for switching the TWC 22 from the reverse state R to the forward state F and the shift range position switching control. In other words, the engine speed Ne, the rotational speed of the input shaft 11 of the automatic transmission 10 (main shaft rotational speed) Nm, the rotational speed Nc of the output shaft (output member 13), and the signal S1 indicating the operating state of the electromagnetic clutches 22a and 22b And S2, and the vehicle speed detection signal V of the vehicle speed sensor 33, and the like. The ECU 30 performs rotation direction detection that detects the TWC state (allowable rotation direction) from the signals S1 and S2.

  Further, the ECU 30 detects the shift range position (position detection) of the automatic transmission 10 based on the signal obtained from the map according to the traveling state of the vehicle, and shifts to the shift range position selected by the shift mechanism of the engagement mechanism. Perform the action.

  The ECU 30 includes a nonvolatile memory such as a CPU, RAM, and EEPROM. The CPU executes various processes including processes to be described later by executing a program stored in the nonvolatile memory using the RAM as a work memory.

  FIG. 8 is a flowchart for explaining TWC switching control.

  The CPU determines whether or not the TWC 22 cannot be switched from the reverse travel state R to the forward travel state F due to the failure of the electromagnetic clutches 22a and 22b (S10). When the switch is impossible, the process will be described later, but the CPU does not execute the following process shown in FIG. When the electromagnetic clutches 22a and 22b are normal (switchable state), the CPU executes the following processing shown in FIG.

  The CPU determines whether or not to switch the TWC 22 from the reverse state R to the forward state F, and whether or not the automatic transmission 10 is shifted from the neutral range position to the second speed or higher (S11). In the following, switching from the reverse state R to the forward state F is “R → F”, the neutral range position is “N range”, the shift range of 2nd gear or higher is “D range”, and the N range to D range. This shift operation is expressed as “N → D”.

  When R → F and N → D are not satisfied, the CPU determines whether or not the automatic transmission 10 is in the N range (S12) and determines the state of the TWC 22 (S13). Then, if the automatic transmission 10 is in a forward speed other than the N range, or the TWC 22 is in the forward state F, the process returns to step S11.

  If R → F and N → D, and the automatic transmission 10 is in the N range and the TWC 22 is in the reverse state R, the CPU determines whether R → F is in progress (S14), vehicle speed V And the specified vehicle speed Vr are compared (S15). If it is not during R → F and V <Vr (the vehicle speed is less than the specified vehicle speed), the process returns to step S11. If R → F or V ≧ Vr (the vehicle speed is equal to or higher than the specified vehicle speed), TWC switching control for switching the TWC 22 from the reverse state R to the forward state F is performed (S16), and the process returns to step S11.

  The specified vehicle speed Vr is a speed in the range of 1 km / h to 2 km / h, for example. That is, switching is performed before the vehicle speed increases and the load of the TWC 22 increases due to the influence of the friction of the carrier C2.

  On the other hand, if it is determined in step S11 that R → F and N → D, the CPU determines the state of the TWC 22 (S17). When the TWC 22 is in the reverse state R, the switching of the automatic transmission 10 from the N range to the D range is prohibited (hereinafter referred to as N → D prohibited) (S18), TWC switching control is performed (S16), and the process is performed. Return to step S11. This N → D prohibition is canceled when it is determined in step S17 that the TWC 22 is in the forward state F (S19). That is, the switching of the automatic transmission 10 from the N range to the D range is waited until the TWC 22 switches from the reverse state R to the forward state F, and after the TWC 22 switches from the reverse state R to the forward state F, the automatic transmission 10 Switching from the N range to the D range is performed.

  FIG. 9 is a flowchart for explaining shift range position switching control in consideration of a state in which the TWC 22 cannot be switched.

  The CPU determines whether or not the automatic transmission 10 is switched from the N range to the D range (N → D) (S21). If not N → D, the process returns to step S21.

  In the case of N → D, the CPU determines a failure of the electromagnetic clutches 22a and 22b (a state in which the TWC 22 cannot be switched from the reverse state R to the forward state F) (S22). If the electromagnetic clutches 22a and 22b are normal (in a state where the TWC 22 can be switched), it is determined whether N → D prohibition is set (S23). If N → D prohibition is set, the process returns to step S21. If N → D prohibition is not set, normal shift range position switching control is performed (S24), and the process returns to step S21.

  If it is determined in step S22 that the switching is impossible, the CPU determines that the engine speed Ne exceeds the predetermined speed and does not enter the red zone when the automatic transmission 10 is engaged with the 2.5 speed shown in FIG. It is determined whether or not (S25). When the engine speed Ne does not exceed the predetermined speed, the automatic transmission 10 is engaged with the 2.5 speed (S26), and when the engine speed Ne exceeds the predetermined speed, N → D prohibition is set (S27). ).

  FIG. 10 is a speed diagram of the automatic transmission 10 showing the 2.5-speed stage. At the 2.5th speed, no interlock occurs even if the carrier C2 of the planetary gear mechanism P2 is fixed while the TWC F1 remains in the reverse state R. That is, when the TWC 22 cannot be switched from the reverse travel state R to the forward travel state F due to the failure of the electromagnetic clutches 22a and 22b, the shift range position is shifted to the 2.5th gear position where no interlock is generated. However, if there is a risk of the engine speed Ne entering the red zone at a high vehicle speed, N → D prohibition is set, and the automatic transmission 10 is not engaged with the 2.5th gear.

  In the above, the automatic disguise in which the TWC is connected to the carrier C2 of the planetary gear mechanism P2 has been described. However, the present invention is also effective for an automatic transmission that uses a brake instead of the TWC (for example, Patent Document 3).

  In this way, in the automatic transmission that switches the forward rotation speed and the reverse speed by switching the allowable rotation direction of the TWC that can switch the allowable rotation direction, the shift range position is in the N range, and the allowable rotation direction of the TWC is the reverse speed. In the direction to be established (reverse drive state R), when the vehicle speed exceeds a predetermined speed, the allowable rotation direction of the TWC is switched to the direction to establish the forward gear (forward drive state F). Further, the shift control according to the map or the like is stopped until the TWC switching is completed.

  Therefore, for example, after the vehicle is moved backward, the vehicle descends in the N range and accelerates, and the interlock that occurs when in-gearing from the N range to the second gear or higher can be avoided. Shift operation (N → D) at higher speeds is possible. Furthermore, since the TWC switching control is executed at a low speed when the drawing load is small, an extra load applied to the TWC can be avoided.

  Further, when the TWC is in a non-switchable state, even when the TWC is in the reverse travel state R, the engagement combination of the engagement mechanisms that can establish the 2.5th speed is executed. However, if there is a risk that the engine speed Ne may enter the red zone at high vehicle speeds, N → D is prohibited.

Claims (5)

An automatic transmission (10) that shifts a driving force from a driving source (20) from a plurality of shift stages to a predetermined shift stage according to a running state of the vehicle, and transmits the shifted driving force to driving wheels of the vehicle. Because
The automatic transmission has a plurality of planetary gear mechanisms (P1-P4) including rotating elements of a sun gear, a carrier, and a ring gear, and a plurality of engagement mechanisms that connect or fix the rotating elements of the planetary gear mechanism. , Establishing the shift stage by a combination of engagement of the plurality of engagement mechanisms,
One of the plurality of engagement mechanisms is a mechanical engagement mechanism (F1) capable of switching an allowable rotation direction allowing one rotation direction of the rotation elements of the plurality of planetary gear mechanisms, and the other engagement mechanisms Is a frictional engagement mechanism (C1-C3, B1-B3), which automatically shifts the mechanical engagement mechanism so that the allowable rotational direction of the mechanical engagement mechanism is switched between forward and reverse speeds. In the machine control device (30),
Position detection means (30) for detecting a shift range position of the automatic transmission;
Rotation direction detection means (30) for detecting an allowable rotation direction of the mechanical engagement mechanism,
When the neutral range position is detected as the shift range position, and the direction for establishing the reverse speed is detected as the allowable rotation direction of the mechanical engagement mechanism, the allowable rotation direction of the mechanical engagement mechanism is set to the forward speed. Automatic transmission control device that switches in the direction to establish. Furthermore, it comprises vehicle speed detection means (33) for detecting the vehicle speed of the vehicle,
2. The automatic transmission control device according to claim 1, wherein when the vehicle speed equal to or higher than a predetermined speed is detected, the mechanical engagement mechanism is switched in a direction to establish the forward gear.   A neutral range position is detected as the shift range position, a direction for establishing the reverse gear is detected as an allowable rotation direction of the mechanical engagement mechanism, a vehicle speed is detected as the predetermined speed or more, and the shift range position is determined. When a signal for shifting to the forward gear is input, the shift to the forward gear is waited until it is detected that the allowable rotation direction of the mechanical engagement mechanism is switched to the direction for establishing the forward gear. 3. A control device for an automatic transmission according to claim 2.   When the allowable rotation direction of the mechanical engagement mechanism cannot be switched from the direction establishing the reverse gear to the direction establishing the forward gear, the allowable rotation direction of the mechanical engagement mechanism establishes the reverse gear 4. The control device for an automatic transmission according to claim 1, wherein a combination of engagement of the engagement mechanisms capable of establishing a predetermined forward speed is executed.   5. The control device for an automatic transmission according to claim 4, wherein when the predetermined forward speed is established, establishment of a gear position is prohibited when it is determined that the internal combustion engine as the driving source exceeds a predetermined rotational speed.

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