JP2005273822A - Shift control device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift control device for an automatic transmission capable of improving the draw shock in the torque phase at the time of up-shifting. <P>SOLUTION: The shift control device of the automatic transmission is equipped with a clutch re-engagement controlling means to execute the release control to lower the engaging capacity of a first engagement element when the specified conditions are met at the time of up-shifting and execute the engage control to raise the engaging capacity of a second engagement element to the level capable of promoting the inertia phase, wherein the specified conditions consist of the specified gear ratio on the lower speed side than the gear ratio before up-shifting generated by lowering the engaging capacity of the first engagement element, and the re-hitch controlling means executes the engaging control of the second engagement element and makes release control so that the engaging capacity of the first engagement element becomes the specified level or below before the gear ratio having once become the specified gear ratio on the lower speed side will get the shift range before up-shifting. <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 fastening / release control of a fastening element during upshifting.

Conventionally, a technique described in Patent Document 1 has been disclosed as a technique for achieving a shift by switching control of a fastening element during an upshift. In this technology, the timing at which the engagement-side hydraulic pressure rises is controlled with respect to the timing at which the release-side hydraulic pressure is released, thereby preventing the pulling of the torque phase and the idling of the engine speed before the increase of the engagement-side capacity. .
JP-A-10-299880 (see page 3).

  However, in the above prior art, a torque phase always occurs at the time of upshift, and the output shaft torque in the torque phase is “input torque multiplied by gear ratio before upshift” to “input The torque drops to “torque multiplied by the gear ratio after upshifting” (pull shock). Therefore, even if optimum hydraulic pressure control is performed, there is a problem that the pulling shock of the output shaft torque in the torque phase cannot be further reduced.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a shift control device for an automatic transmission that can improve a pulling shock caused by a decrease in output shaft torque during upshifting.

  In order to achieve the above object, according to the present invention, the first engagement element that is engaged at the shift stage before the upshift and is released at the shift stage after the upshift, and is released at the shift stage before the upshift, and the upshift is performed. When a predetermined condition is satisfied at the time of upshifting with the second engagement element that is engaged at the subsequent shift stage, release control is performed to reduce the engagement capacity of the first engagement element, and the second engagement element And a switching control means for executing a fastening control for increasing the fastening capacity to a fastening capacity that can promote the inertia phase, wherein the predetermined condition is set to the fastening capacity of the first fastening element. The gear ratio has reached a predetermined gear ratio on the lower speed side than the gear ratio of the shift stage before the upshift, and the switching control means is configured to tighten the second fastening element. In addition to executing the control, after the fastening capacity of the first fastening element reaches the predetermined gear ratio on the low speed side, it becomes equal to or less than the predetermined fastening capacity before reaching the gear ratio of the shift stage before the upshift. We decided to release control.

  Therefore, in the shift control device for an automatic transmission according to the present invention, at the time of upshifting, the input capacity is reduced by reducing the fastening capacity of the first fastening element so that the gear ratio is on the low speed side before the switching control. The rotational speed of the side (for example, the engine) is set to a higher state than the state of the pre-shift gear stage so that higher inertia energy is maintained. Thereafter, the fastening control for the second fastening element starts together with the release control of the first fastening element, and the fastening capacity of the second fastening element increases. As a result, the gear ratio starts to change toward the gear ratio after the end of the shift. Next, the gear ratio that is on the lower speed side than the gear ratio before the upshift reaches the gear ratio that becomes the gear position before the upshift. At this time, the engagement capacity of the disengagement-side first engagement element is set to a predetermined engagement capacity or less before the gear ratio becomes the gear position before the upshift. Originally, the output shaft torque is reduced to the torque obtained by multiplying the input torque by the gear ratio after upshifting due to the torque phase, but since the gear ratio is decreasing, the inertia energy of the engine is simultaneously released to the output shaft torque, The output shaft torque increases accordingly. That is, it is possible to perform the switching control using the ensured inertia, to improve the pulling shock in the torque phase, and to achieve a smooth upshift.

  Hereinafter, the best mode for realizing a fastening element fastening control device according to the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing a hydraulic control device for an automatic transmission according to a first embodiment. An engine 1 that is a power source, an automatic transmission 2, and a control unit 3 that controls the gear ratio of the automatic transmission 2 are provided.

  The automatic transmission 2 shifts the rotation input from the input shaft Input and outputs it to the output shaft Output. In addition, a first engagement element C1 that is engaged when the N speed is achieved as a shift stage and a second engagement element C2 that is engaged when the (N + 1) speed is achieved are provided. These fastening elements C1 and C2 may be a clutch that connects the rotating bodies, or may be a brake that locks the rotating body to a fixed object such as a transmission case. At least the fastening elements C2 make a piston stroke and press This is a fastening element that performs a fastening operation, for example, a multi-plate clutch, a multi-plate brake, and the like. It is controlled by the hydraulic pressure generated by a control valve (not shown). At the time of shifting from the N speed to the (N + 1) speed, at least the first fastening element C1 is released and the second fastening element C2 is fastened. At this time, even if another fastening element (not shown) is fastened, the fastening element remains fastened.

  Further, even when a fastening element is further added to achieve a plurality of shift speeds, a predetermined fastening element before the shift is released and a predetermined fastening element after the shift is fastened at the time of shifting. Any control may be used as long as the speed is changed, and control for changing speed while switching the torque sharing between the fastening element to be released and the fastening element to be fastened is defined as switching control.

  The control unit 3 receives signals from the engine speed sensor 4, the vehicle speed sensor 5, the throttle opening sensor 6, and the piston stroke end determination means 7, and the hydraulic pressure generated by a control valve (not shown) based on these signals. And the engagement capacity of the first engagement element C1 and the second engagement element C2 is controlled. The engine speed represents the input speed (Input speed) input to the automatic transmission 2, and the vehicle speed represents the output speed (Output speed) output from the automatic transmission 2. The gear ratio is expressed by (input rotation speed) / (output rotation speed).

  The piston stroke end judging means 7 is appropriately selected from, for example, ON / OFF of the hydraulic switch installed in the hydraulic circuit of the second fastening element C2, the detected value of the hydraulic sensor, or the elapsed time from the start of the piston stroke control. There is no particular limitation (corresponding to the piston stroke end determination means described in the claims).

FIG. 2 is an alignment chart showing the N speed and the (N + 1) speed in the automatic transmission 2. In FIG. 2, Input represents the rotation speed of the input shaft Input. Output represents the rotation speed of the output shaft Output. The intersection of the axis of M1 and the line of the nomogram represents the number of rotations of the rotating member M1 defined by the fastening of the first fastening element C1, and the intersection of the axis of M2 and the line of the collinear chart represents the second fastening element Represents the rotational speed of the rotating member M2 defined by the fastening of C2. The distances a, b, and c of Input, Output, M1, and M2 represent gear ratios. The relationship between the distances a, b, and c and the gear ratio is as follows.
n-speed gear ratio = (a + b) / b
(n + 1) speed gear ratio = (a + b + c) / (b + c)
In the collinear chart shown in FIG. 2, the relationship of torque can be expressed in addition to the relationship of the rotational speed, and the line that the rigid lever is annotated as n-speed on FIG. 2 is the rigid lever (1), (n + 1 The line annotated with speed is called the rigid lever (2).

The upshift of the first embodiment represents that the rigid lever (1) changes to the state of the rigid lever (2). By the way, the inertia of the output shaft Output (equivalent to the inertia of the vehicle body) is much larger than the inertia of the input shaft Input (equivalent to the inertia of the engine), so the output shaft speed does not change during shifting. .
Further, in this specification, the fastening capacity and the shared torque are defined as follows.
If it demonstrates using the 1st fastening element C1, the torque which the 1st fastening element C1 currently controlled by normal hydraulic pressure etc. can transmit is represented by the following formula | equation according to the oil_pressure | hydraulic at that time.
T = 2 × N × μ × R × (AP-F)
N: Number of clutches
μ: Friction coefficient
R: Clutch radius
A: Clutch pack area (hydraulic pressure receiving area)
P: Hydraulic pressure
F: Return spring force This transmittable torque T is defined as the fastening capacity of the first fastening element. In the case where it is not desired to slide the fastening element at all, the above-described hydraulic pressure is generally set so that the torque is larger than the torque required for actual transmission in consideration of the safety factor. Therefore, the fastening capacity of the first fastening element C1 does not necessarily match the torque T _C1 of the first fastening element that is actually transmitted when the first fastening element C1 is fastened. Here, when the input torque is generated, the torque itself actually transmitted in a state where the first fastening element C1 does not slip at all is defined as C1 shared torque.

In other words, C1 shared torque
(1) When the first fastening element C1 is completely fastened and there is no relative rotation, the C1 shared torque is the torque itself transmitted by the first fastening element C1.
(2) When the first fastening element C1 is slipping and there is relative rotation, the fastening capacity and transmission torque of the first fastening element C1 such that the relative rotational change rate of the first fastening element C1 is zero are C1. This is a shared torque.
It turns out that.

  FIG. 3 is a flowchart showing the change gear shift control at the time of upshift of this embodiment. This flowchart is executed at a predetermined cycle (for example, 10 msec) during the upshift control. FIG. 4 is a time chart showing the control state of the engagement side and the release side during the upshift. R1 to R4 represent the control phase of the release side of the overall upshift control, and A1 to A4 represent the overall upshift control. This represents the control phase on the fastening side.

  In step 101, it is determined whether or not change control A3, R3, which will be described later, has started. If change control A3, R3 has not started, the process proceeds to step 102, and otherwise, the process proceeds to step 109.

  In step 102, it is determined whether or not the gear ratio is larger than the first gear ratio for determining engine blow-off. When the gear ratio is larger, the process proceeds to step 103, and otherwise, the process proceeds to step 106.

  In step 103, it is determined whether or not the piston stroke on the engagement side (second engagement element) has been completed. If it has been completed, the process proceeds to step 104. Otherwise, the process proceeds to step 105.

  In step 104, the switching control A3 is executed on the fastening side (second fastening element), and the switching control R3 is executed on the release side (first fastening element).

  In step 105, piston stroke control A1, which will be described later, is executed on the engagement side (second engagement element), and air blow holding control R2, which will be described later, is executed on the release side (first engagement element). After the gear ratio is greater than the first gear ratio, until the piston stroke is completed, the air blow holding control is executed to suppress the change speed of the gear ratio so that the gear ratio is within a predetermined range from the first gear ratio. Try to keep. (Corresponding to claim 5).

  In Step 106, it is determined whether or not the piston stroke on the fastening side has been completed. If completed, the process proceeds to Step 107. Otherwise, the process proceeds to Step 108.

  In step 107, the engagement capacity retention control A2 is executed on the engagement side (second engagement element), and the air blowing promotion control R1 is executed on the release side (first engagement element). Here, the engagement capacity retention control means that the piston stroke is terminated by the piston stroke end determination means 7 and is controlled in a state where the engagement capacity is almost zero.

  In step 108, the piston stroke control A1 is executed on the engagement side (second engagement element), and the air blow promotion control R1 described later is executed on the release side. As described above, when the switching control is started, it is ensured that the gear ratio surely changes in the gear ratio direction on the low speed side.

  In step 109, it is determined whether or not the gear ratio is larger than a second gear ratio (first gear ratio> second gear ratio ≧ gear ratio of gear before shifting) indicating the end of idling. Otherwise, go to Step 114.

  In step 110, it is determined whether or not the engagement capacity on the release side (first engagement element) remains. If remaining, the process proceeds to step 111. If complete release, the process proceeds to step 114.

  In step 111, it is determined whether or not the fastening capacity on the fastening side (second fastening element) is smaller than the fastening capacity that can promote the inertia phase. If it is small, the process proceeds to step 112. Otherwise, the process proceeds to step 113.

  In step 112, the engagement side change control A3 is executed on the engagement side (second engagement element), and the release side change control R3 is executed on the release side (first engagement element).

  In step 113, inertia phase promotion control A4, which will be described later, is executed on the engagement side (second engagement element), and release side switching control R3 is executed on the release side (first engagement element).

In step 114, inertia phase promotion control A4 is executed on the engagement side (second engagement element), and engagement capacity zero control R4 described later is executed on the release side (first engagement element). As described above, the following is guaranteed for the control after the start of the switching control.
・ When the gear ratio approaches the pre-shift gear ratio, release-side engagement capacity zero control R4 is performed, and the engagement side performs inertia phase promotion control A4.
-When it is determined that the engagement capacity on the release side has become zero, the engagement side immediately performs inertia phase promotion control A4.
-Until the above condition is satisfied, the switching control is performed on both the fastening side and the releasing side. However, the engagement side performs the inertia phase promotion control A4 when the engagement side capacity reaches the engagement capacity capable of promoting the inertia phase.

  The above-described control content will be described with reference to the shift time chart and collinear chart (FIGS. 5 to 8) in FIG. Hereinafter, the engine rotation and the input shaft rotation are expressed in the same way. This is because the rotational speed that is actually handled is the input shaft rotation (turbine rotation), but the inertia that affects the actual shift is caused by the engine.

(Steady state before upshift)
FIG. 5 is a diagram illustrating the torque balance of the rigid lever at the N speed before the upshift. When the torque input from the engine 1 is T _IN , the torque transmitted by the fastening of the first fastening element C1 is T _C1 , and the output shaft torque is T ⁽¹⁾ _OUT , the torque balance is
T _IN + T _C1 = T ⁽¹⁾ _OUT
It is expressed.
If the steady state is at N speed, the moment is
a ・ T _IN −b ・ T _C1 = 0
Therefore,
a ・ T _IN ＝ b ・ T _C1
It is expressed.

(Up-shift start)
At time t1, based on the shift command, the second engagement element C2 on the engagement side executes piston stroke control A1 for ending the piston stroke. Generally, in a fastening element in which a piston presses and generates a fastening force, a fastening force is not generated at a stage where the piston stroke is not completed. That is, at this stage, the fastening capacity of the fastening element does not work according to the command hydraulic pressure. In order to move the fastening capacity of the fastening element according to the command hydraulic pressure, it is essential that the piston stroke is completed. Therefore, together with the shift command, the piston stroke control A1 of the first engagement element C1 on the engagement side is performed, and the switching control is started after the end of the piston stroke (corresponding to claim 5).

  When the piston stroke control A1 is controlled using hydraulic pressure, for example, the command hydraulic pressure is increased by a predetermined gain amount together with the shift command, or a high command hydraulic pressure is initially generated and then held at a lower command hydraulic pressure. Known control such as so-called precharge control can be selectively applied as appropriate, and is not particularly limited.

On the other hand, the first engagement element C1 (release side) executes the idling promotion control R1. Here, the idling promotion control R1 is to reduce the fastening capacity of the first fastening element C1 on the release side to C1 sharing torque T _C1 or less before the fastening capacity of the second fastening element C2 on the fastening side increases. In this control, the gear ratio is changed to a lower speed side than the gear ratio of the gear stage before the shift. Specifically, for example, the engagement capacity of the second engagement element C2 on the release side is reduced stepwise to the engagement capacity equal to or greater than the C1 shared torque T _C1 together with the shift command, and the engagement is performed with a predetermined gain amount from the decreased engagement capacity. Reduce capacity. The predetermined gain amount is preferably set according to the input torque, and is preferably set so that the gain amount increases as the input torque increases.

  At time t2, as a result of the air blowing promotion control R1, the fastening capacity of the first fastening element C1 starts to decrease below the C1 shared torque, so that the torque that can be transmitted by the first fastening element C1 falls below the input torque, and the capacity The first fastening element C1 starts to slide out. At this time, since the input torque acts to increase the input rotation, the input rotation increases and the gear ratio changes to the gear ratio on the low speed stage side.

  At this time, if the amount of gain that decreases the engagement capacity on the release side is too large, the engine speed suddenly increases and the output shaft torque rapidly decreases, so the gear ratio gain amount may be smaller than before. preferable.

Hereinafter, the torque balance state of the rigid lever when the fastening torque T _C1 (torque during idling holding control) of the first fastening element, which is smaller than the C1 shared torque, will be described with reference to FIG. When the output torque is constant and the input torque T _IN (INR) taking into account the inertia change of the input torque is used, the torque balance is expressed by the following (formula 1).
(Formula 1)
T _IN (INR) + T _C1 = T ⁽²⁾ _OUT
Here, T ⁽²⁾ _OUT is the output shaft torque when the first fastening element C1 slips and the engine speed increases. Further, T _IN (INR) is an input torque considering the inertia change, and is obtained by adding a torque corresponding to the inertia change consumed for the engine rotation change from T _IN (input torque not considering the inertia change).

When the engine speed is increasing, the inertia torque is negative,
T _IN (INR) <T _IN
And when the engine speed is decreasing, it becomes a positive value.
T _IN (INR)> T _IN
It becomes.

  Here, other rotational elements in the automatic transmission are compared to the inertia associated with the input shaft (actually the inertia of the engine) and the inertia associated with the output shaft torque (actually the inertia of the vehicle). Since the inertia is so small that it can be ignored, neither the above formula nor the following is considered.

Further, since the rigid lever rotates, the moment is expressed by the following (formula 2).
(Formula 2)
a ・ T _IN (INR) ＝ b ・ T _C1
In this state, the engine speed continues to rise,
T _IN (INR) <T _IN
Thus, it can be seen from this formula that T _C1 is smaller than that when not blowing.
Also, the output shaft torque T ⁽²⁾ _OUT represented by the sum of T _IN (INR) and T _C1 is smaller than before the gear change (T ⁽¹⁾ _OUT > T ⁽²⁾ _OUT ).

  When the gear ratio reaches the first gear ratio set at a lower speed than the gear ratio of the gear stage before the shift representing the engine blown at time t3, when the piston stroke control A1 on the engagement side has not ended. Performs the air blow holding control R2. Here, the idling holding control R2 is a control that suppresses the change speed of the gear ratio and keeps the state in which the gear ratio falls within a predetermined range by the fastening capacity of the first fastening element C1 on the release side. . Specifically, the decrease gain amount of the engagement capacity of the first engagement element C1 is made smaller than before, held at the engagement capacity when the first gear ratio is reached, or less than the C1 shared torque. Thus, the engagement capacity is held with the engagement capacity when the first gear ratio is reached. As a result, the change speed of the gear ratio is suppressed, and the gear ratio is kept within a predetermined range. Then, the idling holding control R2 is continued until the piston stroke control A1 is completed. Note that, when the engagement-side piston stroke control A1 is completed at the time when the gear ratio reaches the first gear ratio, the idle blowing holding control R2 is omitted.

The phenomenon at this time will be described. When considering the above (Formula 2), it can be seen that T _C1 increases and T _IN (INR) also increases. This coincides with the fact that the inertia torque of the negative engine becomes smaller (as the absolute value becomes larger) as the engine speed increase rate becomes smaller.

Further, referring to the above (Equation 1), since T _IN (INR) and T _C1 are both large, T _OUT is also larger while the engine speed continues to rise.
If T _C1 is completely equal to the torque shared by the first fastening element C1,
T _IN (INR) = T _IN
It becomes. This means that the inertia torque is 0, indicating that the engine speed has not changed. It can be seen that this is consistent with the description of the shared torque of the first fastening element C1.

  When the piston stroke control A1 ends at time t4, the switching control A3, R3 for switching the torque sharing is started for both the first fastening element (release side) C1 and the second fastening element (fastening side) C2. Here, the fastening side switching control A3 is a control for increasing the fastening capacity of the second fastening element C2 by a predetermined gain amount toward the inertia phase acceleration capacity, and the releasing side switching control R3 is the first fastening. In this control, the fastening capacity of the element C1 is decreased by a predetermined gain amount toward zero. For example, when controlling using oil pressure, it is preferable to increase the oil pressure by a predetermined gain amount corresponding to the input torque, and to decrease the oil pressure by a predetermined gain amount corresponding to the input torque on the release side.

Here, the operation of the present embodiment will be described in comparison with the conventional example.
(Shifting action of the conventional example)
FIG. 8 is a diagram showing the torque balance of the rigid lever when the conventional switching control is performed in which the engine is not blown. As shown in FIG. 8, the fastening capacity of the first fastening element C1 is reduced (decrease from T _{C1 to} T _C1 ′), and the fastening capacity of the second fastening element C2 is increased (increased from 0 → TC ₂ ′ → TC ₂ ). Let If the output shaft torque in the torque phase immediately after the start of the switching control is T _OUT ′, the torque balance equation at this time is
{(a + b) / b} ・ T _IN (INR) −a / b ・ T _C2 '＝ T _OUT '
It is expressed.
Since T _C2 '> 0, it can be seen that T _OUT ' decreases as T _C2 'increases.
T _C2 when the second fastening element C2 reaches the sharing torque is
T _C2 = {a / (b + c)} ・ T _IN
It is.

When the second fastening element C2 exceeds the shared torque,
T _C2 > {a / (b + c)} ・ T _IN
From Equation 4,
T _C1 <0
It turns out that it becomes. At this time, the output shaft torque T _OUT
{(a + b + c) / (b + c)} ・ T _IN = T _OUT
It turns out that it becomes. That is, the output shaft torque becomes lower than the output shaft torque after the end of the shift. Here, when the fastening capacity of the first fastening element C1 is smaller than a predetermined value, the inertia phase is shifted to the capacity of the second fastening element C2.

  At this time, inertia torque is added to the input torque, and thereafter, the above relational expression is not satisfied. Incidentally, as the input torque including the inertia torque increases, the output shaft torque fluctuates in the increasing direction.

(Shifting action of this embodiment)
FIG. 7 is a diagram showing the torque balance of the rigid lever at the stage when the fastening side and release side switching control A3, R3 is started. The torque of the torque first fastening element C1 is transmitted in the same racing hold control in the manner as described above T _C1, the second engagement element C2 during the shift completion is transmitted to the T _C2.

The following relationship always holds true regardless of the engine blown.
From the relation of torque balance,
(Formula 3)
T _IN (INR) + T _C1 + T _C2 = T ^{3} _OUT
From the moment relationship,
(Formula 4)
a · T _IN (INR) = b · T _C1 + (b + c) · T _C2
Is established.

Here, when torque transmission is performed by the fastening capacity of the second fastening element C2, the torque T _C2 of the second fastening element _C2 is:
T _C2 = {a / (b + c)} ・ T _IN (INR)
It becomes.
At this time, the transmission torque TC1 of the first fastening element C1 does not become 0, so the output shaft torque is
(a + b + c) / (b + c) ・ T _IN (INR) + T _C1 = T _OUT
It becomes.
T _IN (INR)> T _IN
T _C1 > 0
Therefore, it can be seen that at this stage, the output shaft torque T _OUT has not decreased to a torque corresponding to the post-shift gear stage.

When the fastening capacity of the second fastening element C2 reaches the fastening capacity that can promote the inertia phase at the time t5, the inertia phase promotion control A4 is started. Here, the engagement capacity capable of promoting the inertia phase is an engagement capacity in which the gear ratio does not change from the gear ratio after the shift to the gear ratio before the shift only by the engagement capacity on the engagement side. For example, the hydraulic pressure corresponding to this engagement capacity is set based on the parameter according to the input torque and the vehicle speed, and the arrival determination is made based on whether or not the command hydraulic pressure in the switching control A3 has reached this hydraulic pressure. . In addition, the inertia phase acceleration control A4 increases the engagement capacity of the second engagement element C2 on the engagement side with a gentler slope than the engagement side switching control A3, which is determined by the input torque and the vehicle speed from the inertia phase acceleration capacity. In this control, the gear ratio is changed at a desired change speed. The phenomenon at this time will be described. The fastening capacity of the second fastening element C2 is increased, and a torque toward the fastening point of the second fastening element C2 is generated. Then, the torque T _C1 corresponding to the fastening capacity of the first fastening element C1 and the torque T _C2 corresponding to the fastening capacity of the second fastening element C2 act on the rigid lever in the same direction, and push down the engine rotation. That is, the gear ratio again approaches the N-speed gear ratio. This action increases the engine torque by inertia.

  In this embodiment, the second fastening element C2 is allowed to reach a fastening capacity capable of promoting the inertia phase, and the first fastening element C1 is fastened after the second fastening element C2 reaches the inertia phase promoting capacity. The capacity is controlled to be zero. This is because, as described above, the inertia of the engine can be added more efficiently if the fastening torque is applied to the first and second fastening elements C1, C2 as much as possible until the rigid lever approaches N-speed. (Corresponding to claim 2).

At time t6, when the fastening capacity of the second fastening element C2 exceeds the sharing torque and the fastening capacity of the first fastening element C1 becomes zero, the disengagement side switching control R3 is terminated and the fastening capacity zero control R4 is started. Here, the engagement capacity zero control is control for maintaining the engagement capacity on the release side in the zero state. Specifically, when controlling by hydraulic pressure, the command hydraulic pressure is set to zero.
Whether or not the engagement capacity has become zero is determined by providing the piston stroke detection means 7 in the first engagement element C1 and using the result of this detection means or the elapsed time since the command hydraulic pressure commanded zero. Can be judged.

Then, the phenomenon at time t6 will be described. From the expressions 3 and 4, the following relational expression is obtained.
T _IN (INR) + T _C2 = T ^{3} _OUT
a ・ T _IN (INR) ＝ (b + c) ・ T _C2
This is the inertia phase formula itself. It can be seen that the torque equivalent to the inertia torque due to the engine rotation drop is output to the output shaft, and the output shaft torque increases.

At time t7, when the gear ratio reaches the second gear ratio for determining the end of air blowing, the inertia phase promotion control A4 is continued in the second engagement element C2 on the engagement side, and in the first engagement element C1 on the release side. The capacity zero control R4 is continued.
As described above, when the gear ratio is temporarily increased by the engine blown and then returned to the N-speed gear ratio (second gear ratio), the engagement capacity of the first engagement element C1 on the release side remains. As described above, a torque in the direction opposite to the moment in the speed change direction acts on the rigid lever, leading to a pulling shock due to a decrease in the output shaft torque. Therefore, when the gear ratio reaches the second gear ratio, the pulling shock due to the decrease in the output shaft torque can be reliably suppressed by setting the fastening capacity of the first fastening element C1 to zero.

  Although not shown in the time chart, as shown in the flow from step 110 to step 114, the gear ratio reaches the second gear ratio before the fastening capacity of the first fastening element C1 reaches zero. If so, a control command is output so that the engagement capacity is immediately zero. As a result, the transmission shock of the first fastening element C1 is reversed, so that the pulling shock that occurs because the output shaft torque decreases can be minimized.

  Similarly, even before the fastening capacity of the second fastening element C2 reaches the fastening capacity capable of promoting the inertia phase, when the gear ratio becomes smaller than the second gear ratio, the second fastening element C2 The fastening capacity is controlled step by step to the fastening capacity that can promote the inertia phase. Accordingly, pulling shock due to the torque phase can be minimized (corresponding to claim 4).

  FIG. 9 is a diagram illustrating the torque balance when the inertia phase proceeds. After time t7, the inertia phase promotion control A4 is performed in the second engagement element C2 on the engagement side, and the shift is advanced. As shown in FIG. 9, since the fastening capacity of the first fastening element C1 is controlled to 0, the output shaft torque is reduced by reversing the transmission torque of the first fastening element C1 as shown in FIG. Therefore, the pulling shock that occurs is not generated. In addition, although the output shaft rotational speed is substantially constant, the gear ratio decreases after the gear shift compared to before the gear shift, and therefore it is necessary to reduce the engine speed. At this time, the inertia torque of the engine 1 is absorbed and the shift is completed.

  The effects of the upshift control of the shift control device for the automatic transmission according to the first embodiment described above will be listed.

1) At the time of upshift, by reducing the engagement capacity of the first engagement element C1 so that the gear ratio is lower than the gear ratio of the gear stage before the shift (first gear ratio) before the switching control, The inertia energy possessed by the engine rotation is set to a higher state than that at the time of a normal shift stage before shifting. Next, the switching control for switching the torque sharing is started from the state where the gear ratio has changed to the low speed side, and the engagement capacity of the first engagement element C1 on the release side becomes the gear position before the upshift. The following effects can be obtained by setting it to a predetermined fastening capacity or less (desirably zero) before (when the second gear ratio is reached).
By reducing the input rotation in cooperation with the first engagement element C1 and the second engagement element C2, it is possible to reduce the engine rotation without decreasing the output shaft torque to the output shaft torque corresponding to the shift stage after the end of the shift.
-By releasing engine inertia energy higher than normal before reaching the gear ratio of the pre-shift gear stage, the output shaft torque can be made higher than the output shaft torque in the normal torque phase.

  As a result, it is possible to reduce the torque phase pulling shock that could not be avoided in the past, and to achieve a smooth upshift (corresponding to claims 1 and 3). Note that the engagement capacity of the first engagement element C1 when reaching the second gear ratio is not necessarily zero, but the input rotation of the second engagement element C2 after the actual gear ratio falls below the gear ratio of the pre-shift gear stage. It is sufficient that the lowering effect is not extremely disturbed, and the above control can be satisfactorily achieved.

  2) In the second fastening element C2, the inertia phase promoting capacity is reached at a stroke, and in the first fastening element C1, the capacity becomes zero after the second fastening element C2 reaches the fastening capacity capable of promoting the inertia phase. I have control. In other words, after the actual gear ratio falls below the gear ratio of the pre-shift gear stage, the effect of preventing the output shaft torque from dropping can be effectively achieved by reducing the engine speed in cooperation with the first engagement element C1 and the second engagement element C2. Therefore, it is possible to efficiently improve the pulling shock caused by the decrease in the output shaft torque (effect corresponding to claim 2).

  3) If the gear ratio reaches the second gear ratio before the fastening capacity of the first fastening element C1 reaches zero, the fastening capacity is immediately made zero. As a result, by reversing the transmission torque of the first fastening element C1, it is possible to minimize pulling shock that occurs because the output shaft torque decreases (effect corresponding to claim 3).

  4) In the phenomenon described so far, assuming that the decrease in engine rotation after air blown is caused by the large capacity of the first fastening element C1, the gear ratio after the first gear ratio is the gear stage before the shift. After reaching this gear ratio, the rotation reduction temporarily stops, and then the same torque phase as in the prior art may occur again. Therefore, even before the fastening capacity of the second fastening element C2 reaches the inertia phase acceleration capacity, when the gear ratio becomes smaller than the second gear ratio, the fastening capacity of the second fastening element C2 is instantly reduced. The fastening capacity is such that the phase can be promoted. As a result, it is possible to avoid a situation in which the engine rotation drop after the air blow is temporarily stopped, or the torque phase similar to that of the prior art occurs again afterwards (claim). Effect corresponding to item 4).

  5) In the second fastening element C2 (fastening side), the piston stroke control A1 for ending the piston stroke is executed. In other words, the fastening force is not generated until the fastening element has finished the stroke of the piston. If it is attempted to control the fastening capacity before the end of the piston stroke, the fastening element not only generates a capacity, but also behaves with a sudden change in capacity such as overshoot after the end of the piston stroke. It may lead to shift shock. Therefore, by executing the piston stroke control A1, it is possible to quickly respond to the command hydraulic pressure when controlling by hydraulic pressure. Even after the first gear ratio has been reached, if the piston stroke has not ended, the air blow holding control R2 is maintained, and the transfer control is started after the piston stroke has been ended with certainty. Thereby, subsequent switching control can be achieved smoothly (effect corresponding to claim 5).

6) When the gear ratio once rises due to the engine blown and then returns to the N-speed gear ratio (second gear ratio), the fastening capacity of the first fastening element C1 on the disengagement side remains as described above. As described above, a torque in the direction opposite to the moment in the speed change direction acts on the rigid lever, leading to a pulling shock due to a decrease in the output shaft torque. Therefore, when the gear ratio reaches the second gear ratio, the fastening capacity of the first fastening element C1 cannot transmit torque, that is, it is set to zero, so that the pulling shock due to the reduction of the output shaft torque is reliably suppressed. be able to. (Effect corresponding to claim 6)
7) When the piston stroke control A1 on the engagement side has not ended when the gear ratio has reached the first gear ratio set at a lower speed than the gear ratio of the gear stage before the shift representing the engine blown Change the lowering gain amount of the first engagement element C1 on the disengagement side to make it smaller than before, or keep it at the engagement capacity when the first gear ratio is reached, or below the C1 shared torque In this case, the idle blow holding control is performed to hold the engagement capacity with the engagement capacity at the time when the first gear ratio is reached, and the speed of change of the gear ratio is suppressed, and the state where the gear ratio falls within a predetermined range is maintained. I continued to do. Thereby, it is possible to prevent the engine rotation from excessively increasing and the output shaft torque from rapidly decreasing.

8) When performing the idling promotion control R1, the engagement capacity of the second engagement element C2 on the release side is reduced stepwise to the engagement capacity of the C1 shared torque T _C1 or more together with the shift command, and from this decreased engagement capacity When the engagement capacity is decreased by a predetermined gain amount and the gear ratio starts to change to the low speed side, the engagement capacity on the release side is reduced by making the gain reduction amount of the engagement capacity on the release side smaller than before. If the amount of gain is left as it is, there is a risk that the driver will feel uncomfortable with a sudden increase in engine rotation or a sudden decrease in torque on the output shaft. Thus, the driver can feel a sense of incongruity with a sudden decrease in torque, and the gear can be shifted in a short time.

1 is an overall system diagram illustrating a shift control device for an automatic transmission according to a first embodiment. FIG. 3 is an alignment chart (torque balance diagram) of N speed and (N + 1) speed of the automatic transmission according to the first embodiment. 3 is a flowchart illustrating upshift control according to the first embodiment. 3 is a time chart illustrating upshift control according to the first embodiment. FIG. 3 is a collinear diagram (torque balance diagram) in the N-speed steady state of the first embodiment. FIG. 3 is a collinear diagram (torque balance diagram) at the time of air blow promotion control according to the first embodiment. FIG. 3 is a collinear diagram (torque balance diagram) during switching control according to the first embodiment. It is a nomograph (torque balance diagram) showing the upshift control of the prior art. FIG. 3 is a collinear diagram (torque balance diagram) at the time of inertia phase promotion control according to the first embodiment.

Explanation of symbols

1 Engine 2 Automatic transmission 3 Control unit 4 Engine speed sensor 5 Vehicle speed sensor 6 Throttle opening sensor 7 Piston stroke end judging means

Claims (6)

A first engagement element that is engaged at a shift stage before the upshift and released at a shift stage after the upshift;
A second fastening element that is disengaged at the shift stage before the upshift and is engaged at the shift stage after the upshift;
When a predetermined condition is established at the time of upshifting, a release control for reducing the fastening capacity of the first fastening element is executed, and the fastening capacity of the second fastening element is increased to a fastening capacity capable of promoting an inertia phase. Change control means for executing control;
In an automatic transmission shift control device comprising:
The predetermined condition is that the fastening capacity of the first fastening element is reduced, and the gear ratio has reached a predetermined gear ratio on the lower speed side than the gear ratio of the gear position before the upshift,
The switching control means executes the fastening control of the second fastening element, and after the fastening capacity of the first fastening element reaches the predetermined gear ratio on the low speed side, the gear of the gear stage before the upshift A shift control apparatus for an automatic transmission, wherein release control is performed so that the ratio is equal to or less than a predetermined engagement capacity before reaching the ratio. The shift control apparatus for an automatic transmission according to claim 1,
The release control of the first fastening element in the switching control means is characterized in that after the second fastening element rises to a fastening capacity capable of proceeding with an inertia phase, it is controlled to decrease below the predetermined fastening capacity. A shift control device for an automatic transmission. The shift control device for an automatic transmission according to claim 1 or 2,
When the release control of the first engagement element in the switching control means reaches the gear ratio of the shift stage before the upshift from the predetermined gear ratio on the low speed side before the predetermined engagement capacity or less, A shift control apparatus for an automatic transmission, wherein a fastening capacity of the first fastening element is immediately made equal to or less than the predetermined fastening capacity. The shift control apparatus for an automatic transmission according to any one of claims 1 to 3,
The engagement control of the second engagement element in the switching control means is performed when the gear ratio reaches the shift stage before the upshift before the engagement capacity that can promote the inertia phase is reached. A shift control device for an automatic transmission, wherein the engagement capacity of the automatic transmission is immediately set to the acceleration capacity that can be promoted. The shift control apparatus for an automatic transmission according to any one of claims 1 to 4,
The second fastening element is composed of a fastening element that operates when the piston presses,
A piston stroke end judging means for judging whether or not the piston stroke of the second fastening element is finished;
The automatic transmission according to claim 1, wherein the predetermined condition is when a gear ratio reaches a predetermined gear ratio on the low speed side and when it is determined that a stroke of the piston of the second fastening element is finished. Shift control device. The shift control device for an automatic transmission according to any one of claims 1 to 5,
A shift control apparatus for an automatic transmission, wherein the predetermined engagement capacity is a value at which torque transmission is not performed.

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