JPH11159609A - Down shift control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a shock and abnormal sound at coast down shift time, without deteriorating fuel consumption. SOLUTION: In a coast condition, for instance, when a speed change command of a down shift from a 3-speed to 2-speed is generated, a car speed at speed change ending time is estimated, and based on an engine speed at idle time, a car speed range, such that drive force at speed change ending time is a drive, is determined as an inhibition region. When the estimated car speed is in the inhibition region, that is, in the point of time P ending a speed change, when drive force is positive, the concerned coast down shift is inhibited till a speed change command to the next low speed shift. In this way, with the lapse of time, when a transfer is to a speed change of 1-speed shift, the concerned speed change is ended during the time in a condition of drive force 0, and a shock and abnormal sound are prevented in a drive system one-way clutch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a downshift control device for an automatic transmission.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle is provided with a one-way clutch which operates during acceleration for transmitting a driving force from an engine to a wheel side to a drive system and idles with respect to a reverse driving force from the wheel side. Thus, shock and abnormal noise of the drive system due to rotation fluctuation are prevented. On the other hand, when the connection between the wheel side and the engine side is cut off by the one-way clutch that idles when a reverse driving force is generated from the wheel side, the engine braking action cannot be obtained. When a clutch is provided, and especially when an engine braking action is required, the hydraulic clutch for the engine brake is engaged to connect the wheel side and the engine side so that the engine can be driven from the wheel side.

In an automatic transmission, a shift speed is shifted based on a shift line (shift point) determined by a throttle opening corresponding to an engine output based on an operation amount of an accelerator pedal and a vehicle speed. By the way, in the one-way clutch use state, when decelerating with the foot released from the accelerator pedal (coast), the vehicle shifts down at a predetermined vehicle speed. Or shock has occurred. This is probably because the one-way clutch is suddenly engaged when the output shaft torque on the engine side is large (drive state) at the time of completion of the downshift.

[0004] For this reason, the present applicant has filed Japanese Patent Application No. 8-1849.
No. 02 proposed a downshift control device in which a downshift using a one-way clutch is set at a speed higher than the vehicle speed at which the output shaft torque at the shift speed after the downshift is positive is higher than the vehicle speed at which the output shaft torque is positive. .

[0005]

However, the following points have not yet been solved in the above proposed device. That is, (1) when the shift is determined, if a shift shock or an abnormal noise is already generated due to the influence of the vehicle deceleration, the shift shock or the abnormal noise cannot be avoided. (2) In the case of engine braking in which the hydraulic clutch is operated instead of using the one-way clutch, when the driving force changes due to a coast downshift, such as a drive immediately before the start of shifting and a coast during shifting, or a coast during shifting and immediately after the end of shifting, for example. Cannot prevent the shock and abnormal noise caused by the backlash of the drive system that occurs in the vehicle.
(3) Further, in the above device, the downshift shift line is set on the high-speed side in consideration of variations in the engine speed and the vehicle deceleration. Accordingly, the upshift shift line is set on the high-speed side correspondingly. Inevitably, the traveling range at the low speed stage is widened, and it is difficult to improve the fuel consumption characteristics. Accordingly, an object of the present invention is to solve these problems and to provide a further improved downshift control device for an automatic transmission.

[0006]

Therefore, a downshift control device for an automatic transmission according to the present invention transmits a driving force from an engine to a driving system to a wheel side and transmits a driving force to a reverse driving force from the wheel side. Is a downshift control device for an automatic transmission that includes a one-way clutch that idles and a hydraulic clutch in parallel with the one-way clutch, and that determines a gear position based on the vehicle speed. Prohibition area determination means for obtaining a vehicle speed area where a downshift is prohibited, a shift end vehicle speed prediction means for estimating a vehicle speed at the end of a shift, and a vehicle speed area at the end of a coast downshift shift where the coast downshift is prohibited. And a shift state determining means for determining whether or not the vehicle is in the vehicle speed range at the end of the shift in a vehicle speed range in which the coast downshift is prohibited. It was assumed for controlling to prohibit the coast downshift.

When a shift command for downshifting to a low gear is issued in the coasting state, the vehicle speed at the end of shift predicted by the shift end vehicle speed estimating means is determined by the prohibited area determining means based on the engine speed during idling. When the vehicle is in the vehicle speed region where the coast downshift is prohibited, the coast downshift is prohibited until the shift command to the next lower gear. Thus, for example, by setting the vehicle speed range in which the driving force at the end of the shift to be in the driving state as the above-described prohibited area, a shock or abnormal noise near the end of the shift is prevented.

According to a fourth aspect of the present invention, there is provided a prohibition region determining means for obtaining a vehicle speed region for prohibiting a coast downshift based on an engine speed during idling, and a vehicle speed at the start of a shift in a shift in a state where the hydraulic clutch is engaged. And a shift state determining means for determining whether or not the vehicle speed at the start of shifting of the coast downshift is in a vehicle speed region in which the coast downshift is prohibited.
When the vehicle speed at the start of the shift is in the vehicle speed region where the coast downshift is prohibited, the control for prohibiting the coast downshift is performed.

In a so-called one-way clutchless shift in which the hydraulic clutch is engaged and in a downshift in a coast state, the vehicle speed at the start of shifting predicted by the shifting-starting vehicle speed predicting means is prohibited based on the engine speed at idle. When the vehicle is in the vehicle speed region where the coast downshift determined by the determination means is prohibited, the coast downshift is prohibited until a shift instruction to the next lower gear. Thus, a shock at the start of shifting is prevented by setting the vehicle speed range in which the driving force at the start of shifting suddenly changes from positive to negative to the above-described prohibited area.

It is preferable that the prohibition region determining means obtains a vehicle speed region in which the coast downshift is prohibited using a different value according to the load of the auxiliary equipment such as, for example, turning on and off the air conditioner, as the engine speed during idling.

An apparatus according to an eighth aspect of the present invention is an apparatus having both the configuration according to the first aspect and the configuration according to the second aspect.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples. FIG. 1 is a control system diagram relating to an automatic transmission to which the embodiment is applied. An engine control device 3 is connected to the engine 1, and an automatic transmission control device 4 is connected to the automatic transmission 2. The engine control device 3 is connected to an engine rotation sensor 5, a throttle sensor 6, a vehicle speed sensor 7, and a load sensor 8 for auxiliary equipment, etc., for input signals such as an engine speed, a throttle opening, a vehicle speed, and an auxiliary equipment load signal. The fuel injection amount and the ignition timing of the engine are controlled based on this. The accessory load signal is, for example, a signal indicating whether or not the air conditioner is operating.

Similarly, an automatic transmission control device 4 having a computer therein includes an engine rotation sensor 5, a throttle sensor 6, a vehicle speed sensor 7, and a load sensor 8 for auxiliary equipment.
And a current gear position signal from the current gear position detection unit 9 of the automatic transmission, and controls the gear position switching of the automatic transmission 2 based on the input information calculation processing. .

FIG. 2 shows a typical power transmission mechanism of the automatic transmission 2 with four forward speeds and one reverse speed. The torque of the engine output shaft E is transmitted to the input shaft IN via the torque converter T / C, and can be directly transmitted to the input shaft IN by the lock-up clutch L / U. The first planetary gear PL1 is a carrier PC that supports a sun gear S1, a ring gear R1, and a pinion gear P1 meshing with both gears.
The second planetary gear PL2 is composed of a sun gear S2, a ring gear R2, and a carrier PC2 for indicating a pinion gear P2 meshing with both gears. The carrier PC1 of the first planetary gear PL1 can be connected to the input shaft IN via a high clutch H / C.
The sun gear S1 can be connected to the input shaft IN via a reverse clutch R / C.

The carrier PC1 also has a second planetary gear PL2 via a forward clutch F / C and a forward one-way clutch F / OWC connected in series to the forward clutch F / C.
Can be connected to the ring gear R2. Further, an overrunning clutch OR is connected in parallel with the forward clutch F / C and the forward one-way clutch F / OWC.
C is provided, and the carrier PC1 can be connected to the ring gear R2 via this overrunning clutch.

The sun gear S2 of the second planetary gear is always connected to the input shaft IN, and the ring gear R1 of the first planetary gear and the carrier PC2 of the second planetary gear are always connected to the output shaft OUT. The carrier PC1 of the first planetary gear has a low and reverse brake L & R /
B and a row one way clutch L / OWC are additionally provided. Row one way clutch L / OWC is carrier P
Forward rotation in the same direction as the engine output shaft E of C1 is allowed, but reverse rotation is prevented. The sun gear S1 of the first planetary gear is provided with a 2 & 4 brake 2 & 4 / B.

By operating the above-mentioned clutches and brakes in various combinations, the rotation state of each element of the first and second planetary gears is changed, and the rotation speed of the output shaft OUT with respect to the input shaft IN is changed. Fig. 3 shows forward 4-speed reverse 1
The combination of engagement and release of each clutch and brake for obtaining the gear ratio of the gear is shown. In the figure, the circles indicate the fastening state. Forward one-way clutch F / OWC
Corresponds to the one-way clutch of the invention, and operates during acceleration for transmitting the driving force from the engine to the wheel side, and idles with respect to the reverse driving force from the wheel side. Further, the overrunning clutch ORC corresponds to a hydraulic clutch used when an engine braking action is required. A shift in which the forward one-way clutch F / OWC is enabled without engaging the overrunning clutch ORC and a shift in which the forward one-way clutch F / OWC is disabled by engaging the overrunning clutch ORC are possible.

FIG. 4 is a block diagram showing a functional configuration of a downshift control section for coast downshift control in the automatic transmission control device. First, the downshift control unit 10 is provided with a coast determination unit 11 connected to the throttle sensor 6 to determine whether or not the accelerator pedal (not shown) is released from the accelerator pedal (accelerator off) based on the throttle opening signal. Judge. The idle engine speed setting unit 12 to which the coast judging unit 11 is connected is further supplied with an auxiliary load signal from the auxiliary load sensor 8 and an engine speed signal from the engine speed sensor 5.

The idling engine speed setting section 12
The engine idling speed when the load of the auxiliary equipment such as the air conditioner is not loaded is stored in the internal memory from the engine rotation sensor 5 in advance. In the coast state, when the load of the auxiliary equipment is not loaded, the stored idle speed is stored. When the auxiliary machine is operating, the engine speed at which the predetermined number of revolutions corresponding to the auxiliary machine is added to the stored idle speed when the accessory is operated is set as the engine speed at idle. As a result, the engine speed becomes, for example, as shown in FIG. The output of the idling engine speed setting unit 12 is input to the boundary vehicle speed calculation unit 13.

The boundary vehicle speed calculating unit 13 multiplies the engine speed at the end of the shift for determining the coast / drive area at the end of the shift by the idle speed engine speed by the gear ratio of the shift stage after the shift and a predetermined coefficient. Ask. The boundary vehicle speed calculation unit 13 further obtains a shift start boundary vehicle speed for determining a coast / drive area at the start of a shift by multiplying the idle engine speed by the gear ratio of the current shift stage and a predetermined coefficient.

On the other hand, there are provided a time calculating unit 14 connected to the current gear position detecting unit 9 until the shift is completed, and a deceleration calculating unit 15 connected to the vehicle speed sensor 7, each of which estimates a deceleration width until the shift is completed. It is connected to the unit 16. The current gear position detecting section 9 is also connected to a shift start delay time calculating section 17, which is connected to the vehicle speed sensor 7 and a deceleration width estimating section 18 until the shift is started. The deceleration width estimating unit 16 until the shift is completed is connected to a vehicle speed estimating unit 19 at the end of the shift, and the decelerating width estimating unit 18 until the shift is started is connected to a vehicle speed estimating unit 20 at the start of the shift. Parts 19, 2
The vehicle speed sensors 7 are connected to 0, respectively.

When the forward one-way clutch F / OWC is valid, the time calculation unit 14 until the shift is completed, based on the current gear position and the gear position after the gear shift, uses a map set in advance as shown in FIG. Obtain the time from the command to the end of the shift. Further, the deceleration calculation unit 15 calculates the deceleration of the vehicle based on the difference between the previous vehicle speed and the current vehicle speed calculated by multiplying the number of pulses read from the vehicle speed sensor at predetermined short intervals by a constant. Then, the deceleration width estimating unit 16 until the shift is completed obtains a vehicle speed width to be decelerated by multiplying the deceleration by the time until the shift is completed. Thereafter, the vehicle speed estimating unit 19 at the end of the shift obtains the vehicle speed at the end of the shift by subtracting the vehicle speed width decelerating from the current vehicle speed to the end of the shift.

When the forward one-way clutch F / OWC is disabled, that is, when the engine brake is enabled, the shift start delay time calculating section 17 is set in advance as shown in FIG. 7 based on the current shift speed and the shift speed after shifting. The delay time from the shift command to the shift start is determined. Then, the deceleration width estimating unit 18 until the shift is started multiplies the deceleration from the deceleration calculating unit 15 by the time until the shift is started, and obtains a vehicle speed width to be decelerated before the shift is started. Thereafter, the vehicle speed estimating unit 20 at the start of the shift determines the vehicle speed at the start of the shift by subtracting the vehicle speed width that decelerates from the current vehicle speed to the start of the shift.

The outputs of the boundary vehicle speed calculating unit 13 and the vehicle speed estimating unit 19 at the end of the shift are input to a coast / drive determining unit 21 at the end of the shift, where the vehicle speed at the end of the shift is compared with the boundary vehicle speed at the end of the shift. It is determined whether the engine output shaft is in the coast state or the drive state. When the vehicle speed at the end of the shift is higher than the boundary vehicle speed, it is determined that the shift end coast is used, and when the vehicle speed is equal to or lower than the boundary vehicle speed, the drive is the shift end drive. The outputs of the boundary vehicle speed calculating unit 13 and the vehicle speed estimating unit 20 at the start of shifting are input to the coast / drive determining unit 22 at the start of shifting. Similarly to the above, the vehicle speed at the start of the shift is compared with the boundary vehicle speed at the start of the shift, and when the vehicle speed at the start of the shift is greater than the boundary vehicle speed, it is determined that the shift start coast, and when the vehicle speed is equal to or less than the boundary vehicle speed, the drive is the shift start drive. You.

Next, the flow of coast downshift control in the downshift control section 10 will be described. The flowchart in FIG. 8 shows a schematic flow of the control.
First, in the automatic transmission control device 4, as a normal shift control, when a traveling state represented by a throttle opening and a vehicle speed crosses a shift line in a shift point characteristic diagram, a downshift shift command is issued. In 101, the coast determination unit 11 determines whether or not the vehicle is in a coasting state due to the accelerator off based on the throttle opening. When the throttle opening is, for example, 1/8 or less, it is determined that the vehicle is coasting.

If the vehicle is in the coast state, step 10
Then, it is determined whether or not the engine output shaft side is in the coast state at the end of the shift. If it is a coast at the end of the shift, it is checked in step 103 whether or not the forward one-way clutch F / OWC is effective (OWC shift). This check is performed based on a map as shown in FIG.

In the case of the OWC shift, it is determined in step 105 that the vehicle enters the shift permission area, and in step 106, the downshift is executed. On the other hand, the forward one-way clutch F / OWC invalid shift (OWC-
In the case of (Less shift), the routine proceeds to step 104, where it is determined whether or not the engine output shaft side is in a coasting state at the start of shifting. If it is a shift start coast, the routine proceeds to step 105.

If the determination in step 104 is not the shift start coast, it is determined in step 107 that the vehicle is in the shift prohibited area, and in step 108, the downshift is prohibited. As a result, if the shift command is, for example, a downshift from the third speed to the second speed, this is prohibited, and as a result, a shift command for a downshift from the third speed to the first speed is issued next. become. If it is determined in step 102 that the shift end is not the coast, the process proceeds to step 107. Step 101
If it is determined that the accelerator is not in the off-coast state, the routine proceeds directly to step 106, where the downshift is executed.

FIG. 10 shows the details of the coast determination at the end of the shift in the above step 102. First step 20
At 1, the downshift control unit 10 reads signals of a throttle opening, an auxiliary load, an engine speed, a vehicle speed, and a current gear position. Next, in step 202, the time calculation unit 14 until the shift is completed obtains the time until the shift is completed based on the current gear position from the map in FIG. 6, and in step 203, the deceleration is calculated from the change in the vehicle speed.
In step 204, the deceleration width estimating unit 16 until the shift is completed
However, the deceleration width is obtained using the time until the shift is completed and the deceleration, and the vehicle speed estimating unit 19 at the end of the shift calculates the vehicle speed at the end of the shift from the deceleration width and the current vehicle speed.

On the other hand, in step 205, when the coast judging section 11 recognizes the coast state from the throttle opening,
The idling engine speed setting unit 12 obtains the idling engine speed from the map shown in FIG. 5 based on the state of the accessory load. Then, in step 206, the boundary vehicle speed calculation unit 13 calculates the boundary vehicle speed at the end of the coast / drive shift based on the idling engine speed. Thereafter, in step 207, the coast / drive determining unit 21 at the end of the shift compares the vehicle speed at the end of the shift with the boundary vehicle speed at the end of the shift to determine whether the engine output shaft side is in the coast state or the drive state.

The shift start coast judgment at step 104 is the same as the shift end coast judgment described above, as shown in FIG. First, in step 301,
The downshift control unit 10 controls the throttle opening, the auxiliary equipment load,
The signals of the engine speed, the vehicle speed, and the current gear are read. Next, in step 302, the shift start delay time calculation unit 17 calculates the delay time from the shift command to the start of shift from the map of FIG. 7, and in step 303, calculates the deceleration from the change in vehicle speed. In step 304, the deceleration width estimating unit 17 until the shift is started determines the deceleration width using the delay time until the shift is started and the deceleration, and the vehicle speed estimating unit 20 at the start of the shift is determined from the deceleration width and the current vehicle speed. Calculates the vehicle speed at the start of shifting.

In step 305, the previous step 205
Similarly, when the coast determination unit 11 recognizes the coast state from the throttle opening, the idling engine speed setting unit 12 obtains the idling engine speed from the map in FIG. Then, in step 306, the boundary vehicle speed calculation unit 13 calculates the boundary vehicle speed at the start of coast / drive shift based on the idling engine speed. Thereafter, in step 307, the coast / drive determining unit 22 at the start of the shift compares the vehicle speed at the start of the shift with the boundary vehicle speed at the start of the shift to determine whether the engine output shaft side is in the coast state or the drive state.

The above-described coast determination unit 11, idling engine speed setting unit 12, and boundary vehicle speed calculation unit 13 constitute a prohibited area determination unit of the present invention. Further, a time calculating unit 14 until the shift is completed, a deceleration calculating unit 15, a deceleration width estimating unit 16 until the shift is completed, and a vehicle speed estimating unit 1 when the shift is completed.
9, the shift end vehicle speed estimating means is constituted, and the deceleration calculating unit 15, the shift start delay time calculating unit 17, the deceleration width estimating unit 18 until the shift is started, and the vehicle speed estimating unit 20 at the start of the shift start the shift. Vehicle speed prediction means is configured. Further, the coast / drive judging section 21 at the end of the shift and the coast / drive judging section 22 at the start of the shift respectively constitute the shift state judging means.

Since the present embodiment is configured as described above, a downshift without shock or abnormal noise can be obtained. That is, FIG. 12 shows, for example, the OWC-from the fourth speed to the third speed.
This shows the operation in the case of a Less shift, and as shown in FIG. 9A, when the drive state is entered at the end of the shift, the gradient of the change in the driving force is large, and the point at which the driving force changes from negative to positive at the point P is reversed. Rush shock occurs. In this case, in the present embodiment, for example, as shown in FIG.
The shift from the third speed to the third speed is prohibited, and a shift instruction to the second speed is awaited. As a result, if the shift is completed while the driving force is negative in the downshift from the fourth speed to the second speed while the driving force is negative, the shock due to the sudden change in the driving force is eliminated. If the driving force at the end of the shift is positive and the drive state is established even in the downshift to the second speed, the shift is further prohibited and a shift instruction to the first speed is waited.

In the case of the OWC-Less shift, as shown in FIG. 13A, for example, in the shift command from the third speed to the second speed, when the drive state at the start of the shift is changed, the driving force changes. At a point R at which the driving force changes from positive to negative, a shock due to backlash occurs. In such a case, in this embodiment, the shift from the third speed to the second speed is prohibited, and a shift command to the first speed is awaited. Since the shift from the third speed to the first speed is an OWC shift, the driving force does not become negative as shown in (b) of the figure, so that a shock due to the change from positive to negative is eliminated.

In the examples of FIGS. 12 and 13 described above, the downshift by the first shift command is the OWC-Less shift, but FIG. 14 shows the case of the automatic transmission in which the downshift at the start stage is the OWC shift. Show. Conventionally, when the deceleration is small, the transmission of the driving force is interrupted at the start of the shift and then at the end of the shift, the driving force is still zero due to idling by the forward one-way clutch F / OWC as shown in FIG. There is no shock. However, when the deceleration is large and the driving force is already positive (drive state) at the shift end point P as shown in (b) of the figure and the rise is steep, a large shock occurs. .

On the other hand, according to the application of the present embodiment, for example, when the drive state is assumed at the end of the shift in the shift command from the third speed to the second speed, as shown in FIG. The shift from the third speed to the second speed is prohibited. As a result, as the time elapses, the next shift line is reached and a shift command to the first speed is made. Thus, the start of the shift is delayed and the rise of the driving force is also delayed, and the shift to the first speed is completed while the driving force is still zero. Therefore, even when the deceleration is large, a downshift without shock or abnormal noise can be obtained.

Further, in the present embodiment, the boundary vehicle speed is obtained based on the idling engine speed in the determination of the downshift prohibition area, so that the fuel consumption is increased as compared with the conventional high speed shift. There is no.

[0039]

As described above, according to the present invention, in the downshifting in the coast state, the vehicle speed range in which the driving force at the end of the shift is in the driving state, for example, based on the engine speed during idling, is reduced. The shift is prohibited as a vehicle speed region, and the vehicle speed at the end of the shift is predicted by the vehicle speed prediction means at the end of the shift. When the vehicle speed is in the vehicle speed region where the coast downshift is prohibited, the coast downshift is prohibited and the Since the control waits until the shift command to the next lower gear, shocks and abnormal sounds near the end of the shift are prevented.

In a so-called one-way clutch-less shift downshift, for example, a vehicle speed range in which the driving force at the start of the shift suddenly changes from positive to negative is defined as a vehicle speed range in which the coast downshift is prohibited. When the vehicle speed at the start of the shift predicted by the vehicle speed prediction means at the start of the shift is in a vehicle speed region in which the coast downshift is prohibited, the coast downshift is prohibited and the control waits until a shift command to the next lower gear. ,
Shock at the start of shifting is prevented.

Further, since the determination of the vehicle speed range in which the coast downshift is prohibited is based on the idling engine speed, the fuel consumption is reduced as compared with the conventional shift point set to a higher speed side. It has the advantage that.

[Brief description of the drawings]

FIG. 1 is a control system diagram relating to an automatic transmission to which an embodiment of the present invention is applied.

FIG. 2 is a skeleton diagram showing a power transmission mechanism of the automatic transmission.

FIG. 3 is a diagram showing a combination of engagement and release of a clutch and a brake in a power transmission mechanism.

FIG. 4 is a block diagram illustrating a configuration of a downshift control unit in the automatic transmission control device.

FIG. 5 is a diagram showing a map for setting an engine speed during idling.

FIG. 6 is a diagram showing a map for calculating a time from a shift command to the end of a shift.

FIG. 7 is a diagram showing a map for calculating a delay time from a shift command to the start of a shift.

FIG. 8 is a flowchart schematically showing a flow of coast downshift control.

FIG. 9 is a map showing shift types in which a one-way clutch is enabled or disabled.

FIG. 10 is a flowchart illustrating details of a coast determination at the end of a shift.

FIG. 11 is a flowchart illustrating details of a coast determination at the start of a shift.

FIG. 12 is a diagram showing a change in driving force near the end of a shift in a shift in which a one-way clutch is effective, in comparison with a conventional example.

FIG. 13 is a diagram showing a change in driving force near the end of a shift in a one-way clutch invalid shift in comparison with a conventional example.

FIG. 14 is a diagram showing a change in driving force at the start of a shift in a one-way clutch invalid shift in comparison with a conventional example.

[Description of Signs] 1 Engine 2 Automatic transmission 3 Engine control device 4 Automatic transmission control device 5 Engine rotation sensor 6 Throttle sensor 7 Vehicle speed sensor 8 Auxiliary equipment load sensor 9 Current gear position detection unit 10 Downshift control unit 11 Coast determination unit 12 Idle engine speed setting unit 13 Boundary vehicle speed calculation unit 14 Time calculation unit until shift end 15 Deceleration calculation unit 16 Deceleration width estimation unit until shift end 17 Shift start delay time calculation unit 18 Before shift start Deceleration width estimating unit 19 Vehicle speed estimating unit at the end of gear shifting 20 Vehicle speed estimating unit at the start of gear shifting 21 Coast / drive judging unit at the end of gear shifting 22 Coast / drive judging unit at the start of gear shifting E Engine output shaft T / C Torque converter IN Input shaft L / U Lock-up clutch PL1 First planetary gear PL2 Second plastic Tally gear S1, S2 Sun gear R1, R2 Ring gear PC1, PC2 Carrier P1, P2 Pinion gear H / C High clutch R / C Reverse clutch F / C Forward clutch F / OWC Forward one-way clutch ORC Overrunning clutch OUT Output shaft L & R / B Low And reverse brake L / OWC low one way clutch 2 & 4 / B 2 & 4 brake

Claims (8)

[Claims] A one-way clutch that transmits a driving force from an engine to a wheel side to a driving system and idles with respect to a reverse driving force from the wheel side, and a hydraulic clutch in parallel with the one-way clutch, based on a vehicle speed. A downshift control device for an automatic transmission that determines a shift speed by determining a vehicle speed range in which a coast downshift is prohibited based on an engine speed during idling; and A shift speed predicting means at the end of a shift to be predicted, and a shift state determining means for determining whether the vehicle speed at the end of the shift of the coast downshift is in a vehicle speed region in which the coast downshift is prohibited is provided. When the vehicle speed is in a vehicle speed range in which a coast downshift is prohibited, control is performed to prohibit the coast downshift. Downshift control device. 2. The automatic vehicle according to claim 1, wherein said prohibited area determining means sets a vehicle speed at which a driving force at the end of a shift is in a driving state as a vehicle speed area in which said coast downshift is prohibited. Transmission downshift control device. 3. The vehicle speed estimating means at the end of a shift includes a deceleration calculating unit for obtaining a deceleration of the vehicle, and a time calculating unit for obtaining a time from a shift command of the coast downshift to the end of the shift, to a shift end. The downshift control device for an automatic transmission according to claim 1 or 2, wherein a vehicle speed at the end of the shift is predicted from the deceleration and a time from the shift command to the end of the shift. 4. A one-way clutch that transmits a driving force from an engine to a wheel side to a driving system and idles with respect to a reverse driving force from the wheel side, and a hydraulic clutch in parallel with the one-way clutch, based on a vehicle speed. A downshift control device for an automatic transmission that determines a shift speed by using a prohibited range determining unit that determines a vehicle speed range in which a coast downshift is prohibited based on an engine speed during idling; Shift start vehicle speed prediction means for predicting a vehicle speed at the start of a shift in a shift, and a shift state determination for determining whether the vehicle speed at the start of a coast downshift shift is in a vehicle speed region in which the coast downshift is prohibited. Means for prohibiting the coast downshift when the vehicle speed at the start of the shift is in a vehicle speed region where the coast downshift is prohibited. A downshift control device for an automatic transmission, characterized by performing the following control. 5. The vehicle speed estimating means at the start of a shift includes a deceleration calculating unit for obtaining a deceleration of the vehicle, and a shift start delay time calculating unit for obtaining a time from a shift command of the coast downshift to the start of the shift. 5. The downshift control device for an automatic transmission according to claim 4, wherein the vehicle speed at the start of the shift is predicted from the deceleration and the time from the shift command to the start of the shift. 6. The vehicle according to claim 6, wherein the prohibition region determining means obtains a vehicle speed region in which the coast downshift is prohibited based on an engine speed at the time of idling which differs depending on a load of an auxiliary machine. The downshift control device for an automatic transmission according to 1, 2, 3, 4, or 5. 7. The air conditioner according to claim 6, wherein the prohibited area determining means uses a different value as the engine speed during idling depending on whether the air conditioner is on or off. Automatic transmission downshift control device. 8. A one-way clutch that transmits a driving force from an engine to a wheel side to a driving system and idles with respect to a reverse driving force from the wheel side, and a hydraulic clutch in parallel with the one-way clutch, based on a vehicle speed. A downshift control device for an automatic transmission for determining a shift stage by determining a first vehicle speed region at the end of a shift for inhibiting a coast downshift based on an engine speed during idling. Determination means, speed change end vehicle speed prediction means for predicting the speed of the vehicle at the end of the shift, and determining whether or not the vehicle speed at the end of the shift of the coast downshift is in a first vehicle speed region in which the coast downshift is prohibited. A first shift state judging means and a second shift start state for prohibiting a coast downshift in a state where the hydraulic clutch is engaged, based on an engine speed during idling. A second prohibition area determining means for determining a vehicle speed area, a shift start vehicle speed prediction means for predicting a vehicle speed at the start of a shift in a shift with the hydraulic clutch engaged, and a vehicle speed at a start of a coast downshift. Second shift state determining means for determining whether or not the vehicle is in a second vehicle speed region for inhibiting the coast downshift, wherein the vehicle speed at the end of the shift inhibits the coast downshift.
When the vehicle speed is in the second vehicle speed region in which the shift down is prohibited in the shift with the hydraulic clutch engaged, the coast downshift is prohibited. A downshift control device for an automatic transmission, which performs control to inhibit downshifting.