JP2919041B2 - Transmission control device for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a shift control device of an automatic transmission, and more particularly to a measure to reduce shift shock.

(Prior art) Conventionally, an automatic transmission has a speed at which an engine brake is effective by the action of a one-way clutch. In the automatic speed change to this speed, the frictional element to be released is engaged while still firmly engaged. If the frictional element to be fastened is early, the one-way clutch will not allow reverse rotation and will cause internal locking.

For this reason, as disclosed in Japanese Patent Publication No. 63-63778, the present applicant delays the engagement of the friction element that controls the operation of the one-way clutch for a set time, thereby effectively preventing the internal lock and thereby preventing the shift shock. It proposes a product that enables smooth shifting with less noise.

(Problems to be Solved by the Invention) However, in the above-mentioned proposal, the internal lock can be effectively prevented in many cases. However, depending on the driving state, the internal lock rarely occurs and a shift shock is given to the driver. On the contrary, the fastening of the friction element is sometimes too late to give a feeling of idling of the vehicle.

The present invention has been made in view of such a point, and an object of the present invention is to change a delay time for delaying engagement of a friction element to be engaged to an operation state when shifting to a gear position where an internal lock is generated by the action of a one-way clutch. By appropriately changing the timing, the engagement timing of the friction element is always appropriate regardless of the driving state, so that the shift shock caused by the internal lock is effectively reduced or eliminated, and the feeling of idling of the vehicle is eliminated. It is in.

(Means for Solving the Problems) In order to achieve the above object, a solution of the invention according to claim 1 is a one-way clutch provided in a speed change gear mechanism, and an engine brake provided in parallel with the one-way clutch to act. A plurality of friction elements including a predetermined friction element for switching the operation state of the plurality of friction elements, thereby achieving a plurality of gear steps including a gear step in which an engine brake operates, and the engine A speed change gear mechanism when a plurality of friction elements to be engaged at a shift speed before and after a shift and a predetermined friction element for applying an engine brake are simultaneously engaged at the time of shifting to a shift speed at which a brake acts, Speed detection means for detecting the input-side rotation speed of the transmission, and a reduction in engine load When the gear is shifted to the speed at which the engine brake operates, the input rotation speed of the transmission is set to a predetermined value with respect to the predicted input rotation speed at the end of the shift from the time of the shift command to the engagement of the predetermined friction element to be engaged. And delay means for delaying until the number of rotations has the relationship of

According to a second aspect of the present invention, there is provided a one-way clutch provided in a speed change gear mechanism, and a plurality of friction elements including a predetermined friction element provided in parallel with the one-way clutch for operating an engine brake. By switching the operating states of the plurality of frictional elements, a plurality of shift speeds including a shift speed on which the engine brake operates are achieved, and before and after shifting to a shift speed on which the engine brake operates. In an automatic transmission configured such that an internal lock is generated in a transmission gear mechanism when a plurality of friction elements to be engaged in a subsequent gear and a predetermined friction element for applying an engine brake are simultaneously engaged, Speed detecting means for detecting the input side speed of the engine, and shifting to a speed at which the engine brake operates due to a decrease in engine load. When the gear ratio is the same as the gear ratio of the gear before or after the gear change, the input side rotational speed of the transmission is changed from the time of the gearshift command to the time of the gearshift command to the engagement of the predetermined friction element to be engaged. And delay means for delaying the rotation speed to a rotation speed having a predetermined relationship with the predicted input rotation speed.

(Operation) With the above-described configuration, in the first and second aspects of the present invention, when shifting to a shift position where the engine brake operates, when the shift is at the time of deceleration due to a decrease in engine load, the driver is caused by the internal lock. It is easy to feel the shifting shock. However, at the time of such a shift, the engagement of the friction element is started for the first time when the input side rotation speed of the transmission becomes appropriate at each shift, so that the internal lock is always reliably prevented regardless of the operation state. As a result, the shift shock is effectively reduced and eliminated, and there is no delay in the engagement of the friction element, so that the feeling of idling of the vehicle can be prevented and an appropriate engine brake can be applied.

(Effects of the Invention) As described above, according to the shift control device for an automatic transmission according to the first and second aspects of the present invention, when shifting to a gear at which engine braking is effective due to a decrease in engine load, friction to be engaged is set. Since the fastening timing of the elements can be appropriately adjusted according to the operating state, the internal lock can be reliably prevented regardless of the operating state, and the shift shock can be effectively reduced,
It is possible to prevent the friction element from being fastened too late, and to eliminate the feeling of idle running of the vehicle given to the driver.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an automatic transmission Z having four forward speeds and one reverse speed,
1 is an engine output shaft, 2 is a torque converter provided with a pump 2a connected to the engine output shaft 1, a stator 2b, and a turbine 2c. The stator 2b reverses the stator 2b from the turbine 2c. It is provided so as to be fixed to the case 4 via a one-way clutch 3 for preventing rotation in the direction. 5 is a turbine 2c of the torque converter 2.
This is a transmission gear mechanism connected to a converter output shaft 2d connected to the transmission gear shaft.

The speed change gear mechanism 5 includes a Ravigneaux type planetary gear mechanism 7 therein. The long pinion gear 11 meshes with the large diameter sun gear 9 and the short pinion gear 10, and a ring gear 12 meshes with the long pinion gear 11. The small-diameter sun gear 8 includes a forward clutch 15 and a clutch 15
Are connected in series to the output shaft 2d of the torque converter 2 via a first one-way clutch 16 for preventing reverse driving of the converter output shaft 2d. A coast clutch 17 is connected in parallel to a path connecting the forward clutch 15 and the first one-way clutch 16 in series. The large-diameter sun gear 9 has a 2-4 brake 18 and a 2-4 brake arranged diagonally rearward.
It is connected to the output shaft 2d of the torque converter 2 via a reverse clutch 19 arranged behind the brake 18. The long pinion gear 11 has a low & reverse brake 21 for fixing the long pinion gear 11 via a rear carrier 20 and a second one-way for allowing the long pinion gear 11 to rotate in the same direction as the engine output shaft 1. The clutch 22 is connected in parallel, and the front carrier 23 is connected to the output shaft 2d of the torque converter 2 via a 3-4 clutch 24. Further, the ring gear 12 is connected to an output gear 25 disposed in front of the ring gear 12. In the figure, reference numeral 27 denotes a lock-up clutch that directly connects the engine output shaft 1 and the converter output shaft 2d, and reference numeral 28 denotes an oil pump driven by the engine output shaft 1 via an intermediate shaft 29.

Table 1 shows the operating states of the clutches and brakes at the respective gears in the above configuration.

Here, in the above Table 1, the D position indicates an automatic shift between the first speed and the fourth speed, the S position indicates an automatic shift between the first speed and the third speed, and the L position indicates the first and second speeds. Each of the automatic shifts between speeds is shown.

Next, a hydraulic circuit for supplying and discharging hydraulic oil to and from each friction element such as the 2-4 brake 18 will be described with reference to FIG. Here, among the above frictional elements, 2-4 brake 18
The servo mechanism 45 as a hydraulic actuator is composed of a servo piston having an apply chamber 45a and a release chamber 45b. When a release pressure does not act on the release chamber 45b and a fastening pressure acts on the apply chamber 45a, a 2-4 brake is applied. 18 and the action of fastening pressure on the application chamber 45a.
When the release pressure acts on the release chamber 45b regardless of the non-operation, the 2-4 brake 18 is released.
Further, the other friction elements are constituted by ordinary hydraulic pistons, and are adapted to fasten the friction elements when hydraulic oil is supplied.

That is, the internal structure of the servo mechanism 45 is 2-4 brakes.
18, a piston 45c connected via a rod 18a, a hydraulic release chamber 45b and an apply chamber 45a partitioned vertically in the figure by the piston 45c, and a piston 45c compressed by the release chamber 45b to form an apply chamber. And a spring 45d for urging toward the 45a side. The piston 45c has a larger pressure receiving area in the release chamber 45b,
When the release pressure (line pressure) acts on the release chamber 45b irrespective of the action of the fastening pressure (line pressure) of the apply chamber 45a, due to the difference in the pressure receiving area, With the release pressure, the piston 45c is moved downward in the drawing to operate the 2-4 brake 18 to the release side. When the 2-4 brake 18 is requested to be engaged, the engagement pressure is introduced into the apply chamber 45a and the release pressure of the release chamber 45b is released, thereby moving the piston 45c upward in the drawing, thereby causing the 2-4 brake 18 to move upward. Is concluded.

Next, the hydraulic circuit 60 shown in FIG. 2 is provided with a pressure regulator valve 61 for adjusting the pressure of the hydraulic oil discharged from the oil pump 28 shown in FIG. 1 to the main line 100 to a predetermined line pressure. I have. Further, near the pressure / regulator valve 61, a throttle valve 62 for generating a throttle pressure corresponding to the throttle valve opening of the engine, a throttle modulator valve 63 for adjusting the throttle pressure, and a backup valve 93 are provided. Is provided.

The hydraulic circuit 60 also has a manual valve 64 for selectively sending the line pressure generated by the pressure / regulator valve 61 to each hydraulic line according to the selected range, and a line pressure that operates according to the gear position. 1-2, 2-3, and 3-4 for selectively supplying the friction elements to the friction elements.

The manual valve 64 has an input port f into which line pressure is introduced from the main line 100, and first to fifth output ports a to e. Then, the first and second output ports a and b
In the S range, the first, second, and third output ports a, b, and c
In the range, it is connected to the first, third, and fourth output ports a, c, and d, and in the R range, it is connected to the fifth output port e. The first to fifth output lines 101 to 105 are connected to the output ports a to e, respectively.

In addition, the 1-2, 2-3, 3-4 shift valves 71, 72, 73
Has a structure in which the spools 71a, 72a, 73a are urged to the right in the drawing by springs, and control ports 71b, 72b, 73b are provided on the right side of these spools. A first control line 106 branched from the main line 100 is connected to a control port 71b of the 1-2 shift valve 71.
The control ports 72b, 73b of the -3, 3-4 shift valves 72, 73 are connected to the second and third control lines 107, 108 branched from the first output line 101, respectively. Contains the first, second and third
Solenoid valves 76, 77, 78 are provided. When these solenoid valves 76 to 78 are OFF, respectively, the control pressure is introduced into the control ports 71b to 73b of the shift valve to position the spools 71a to 73a on the left side in the drawing.
When ON, the control pressure in the control ports 71b to 73b is drained to position the spools 71a to 73a on the right side.

Here, these solenoid valves 76 to 78 are controlled to be turned on and off in accordance with the gear to be set according to the vehicle speed of the vehicle and the throttle valve opening of the engine. The combination pattern of ON and OFF of each of the solenoid valves 76 to 78 at each shift speed is set as shown in Table 1 above.

On the other hand, among the first to fifth output lines 101 to 105 connected to the output ports a to e in the manual valve 64, the first output which is communicated with the main line 100 in each of the forward ranges D, S, and L. Line 101 is led to forward clutch 15 via one-way orifice 80. Therefore, the forward clutch 15 is always engaged in the D, S, and L ranges. Incidentally, the first output line 101 is provided with an ND accumulator 81 for buffering when the forward clutch is engaged.

A line 111 is branched from the first output line 101 and led to the 1-2 shift valve 71. The branch line 111 is connected to the first solenoid valve 7.
When 6 is turned on and the spool 71a moves to the right, the apply chamber of the servo mechanism 45 via the one-way orifice 82
It is communicated with the servo apply line 112 reaching 45a. Therefore, when the first solenoid valve 76 is ON in the D, S, L ranges,
That is, 2, 3, and 4 speeds in the D range, 2 and 3 speeds in the S range, and L
At the second speed in the range, the fastening pressure is introduced into the apply chamber 45a. The servo apply line 112 is also provided with a 1-2 accumulator 83 for buffering when the servo mechanism 45 (2-4 brake) is engaged.

Further, the second output line 102 communicating with the main line 100 in the D and S ranges is led to a 2-3 shift valve 72. The line 102 is connected to the second solenoid valve 7
When 7 is OFF and the spool 72a is located on the left side, it is connected to the 3-4 clutch line 113 through the one-way orifice 84 to the actuator 43a of the 3-4 clutch 24. Therefore, when the second solenoid valve 77 is OFF in the D and S ranges,
That is, the 3-4 clutch 24 is engaged at the 3rd and 4th speeds of the D range and the 3rd speed of the S range. In the 3-4 clutch line 113, a bypass valve 85 and a 2-3 timing valve 86 are provided in parallel with the one-way orifice 84 so as to adjust the engagement timing of the 3-4 clutch 24. The 3-4 clutch line 113 is also provided with a 2-3 accumulator 87 for buffering when the 3-4 clutch is engaged.

Further, a line 114 branched from the 3-4 clutch line 113 and a line 115 branched from the first output line 101 are led to the 3-4 shift valve 73. When the third solenoid valve 78 is turned off and the spool 73a is located on the left side, a line 114 branched from the 3-4 clutch line 113 forms a servo release line that reaches the release chamber 45b of the servo mechanism 45 via the one-way orifice 88. 116 and a line branched from the first output line 101
115 are respectively connected to a coast clutch line 117 leading to the coast clutch 17 via the one-way orifice 89. Therefore, when the second and third solenoid valves 77 and 78 are both OFF in the D and S ranges, that is, when the third speed and the S
At the third speed of the range, the release pressure is introduced into the release chamber 45b of the servo mechanism 45, and the 2-4 brake 18 is released.
When the third solenoid valve 78 is OFF in the L range, that is, the 3rd speed in the D range, the 3rd speed in the S range, the 2nd speed in the L range, and the 2nd and 3rd speeds when operating the hold switch in the S range, the L range 1 when the hold switch is operated
The coast clutch 17 is engaged in the first and second speeds.

Here, the 3-4 clutch line 113 and the line 1
A 3-2 timing valve for adjusting the timing of discharging the 3-4 clutch pressure and the release pressure to the release chamber 45b of the servo mechanism 45 via the respective branch lines 118 and 119 between the line 114 branched from the line 13 and the line 114. 90 and a 3-2 capacity valve 91 are provided. The coast clutch line 117 is provided with a bypass line 120 that bypasses the one-way orifice 89.
Is provided with a 3-4 capacity valve 92 for opening and shutting off. The valve 92 is connected to the bypass when the 3-4 clutch pressure is generated and when the manual valve 64 is selected to the S range or the L range and the third output line 103 is connected to the main line 100. The line 120 is opened, and the timing of discharging the coast clutch pressure is adjusted.

The fourth output line 104 communicated with the main line 100 in the L range by the manual valve 64 is led to the 1-2 shift valve 71 via the low reduction valve 94 and the line 122. And, when the first solenoid valve 76 is OFF and the spool 71a is located on the left side, the line 122 is communicated with a low & reverse brake line 123 leading to the low & reverse brake 21 via the one-way orifice 95 and the shuttle valve 96. You. Therefore, when the first solenoid valve 76 is OFF in the L range, that is, at the first speed in the L range, the low & reverse brake 21 is engaged.

Further, a fifth output line 105 communicating with the main line 100 in the R range communicates with the low & reverse brake line 123 via the one-way orifice 97 and the shaft valve 96, and a one-way from the fifth output line 105. A reverse clutch line 124 that reaches the reverse clutch 19 via the orifice 98 is branched. Therefore, in the R range, the low & reverse brake 21 and the reverse clutch 19 are always engaged. Note that the reverse clutch line 125 is also provided with an NR accumulator 99 for buffering when the reverse clutch is engaged. Further, a line 125 branched from the fifth output line 105 is led to the pressure increasing side of the regulator valve 61 so as to increase the line pressure in the R range.

In addition to the above configuration, the hydraulic circuit 60 includes a lock-up clutch 27 in the torque converter 2 shown in FIG.
Is provided with a lock-up valve 201 for activating the switch. A torque converter line 202 is led from the pressure / regulator valve 61 to the valve 201, and a main line 10 is connected to a control port 201b at one end.
0 is connected as the control line 203. When the lock-up solenoid valve 204 provided on the control line 203 is turned on, the control pressure in the control port 201b is drained, and the spool 201a is located on the right side. Communicates with a line 205 communicating with the inside of the torque converter 2, whereby the internal pressure of the torque converter 2 is increased and the lock-up clutch 27 is engaged. In addition, the solenoid valve 204
Is turned off and the control pressure is introduced into the control port 201b to move the spool 201a to the left, the torque converter line 202 communicates with the lock-up release line 206, and the lock-up release pressure enters the torque converter 2. Is introduced and the lock-up clutch 27 is released.

Each of the above shift controls is performed by a controller 150 shown in FIG.
The switching means 153 for controlling the engagement and disengagement of the plurality of friction elements provided in the transmission gear mechanism 5 to switch the shift speed by the shift control shown in Table 1 according to the first embodiment.

As shown in the figure, the controller 150 has an opening sensor 151 for detecting the throttle valve opening of the engine,
A rotation speed sensor 152 as rotation speed detecting means for detecting the input rotation speed of the automatic transmission Z based on the rotation speed of the turbine 2c of the torque converter 2 is connected.

Next, the shift control at the time of the 2 → 3 shift (each control of the engagement → release of the 2-4 brake 18 and the release → engagement of the 3-4 clutch 24) will be described based on the control flow of FIG.

After starting, the throttle valve opening θ is determined whether or not less than a minute set value (e.g., 1/32 opening value) in step S _1,
The reduction state of the engine load theta <1/32, selects a control pattern of the solenoid valves 76 to 78 to the first intermediate position of the second table below in step S _2. As a result, as shown in FIG. 5, the engagement pressure acting on the apply chamber 45a of the servo mechanism 45 is released, and at the same time, the engagement pressure is supplied to the 3-4 clutch 24 to start the third speed. The first intermediate position is different from the third speed in that the coast clutch 17 is released and the engine brake is not applied, but the gear ratio is the same as the third speed.

Thereafter, to the third speed to conclude a coast clutch 17 after the set time for the gear position effective against the engine brake, first reads the actual turbine speed TREVO during the shift started in step S _3, the speed change in step S ₄ Calculate the predicted turbine speed TREV1 after completion. Then, Step from S ₅ in the fourth map data stored in the pre-controller 0.99 ROM as shown in the figure, a somewhat higher rotational speed TREVB than expected rotational speed TREV1 after the shifting, the actual turbine rotational speed T
Reads in accordance with REVO. Here, the map data in FIG. 4 is set so that the higher the actual turbine speed TREVO, the higher the additional speed TREVB. This is because the higher the actual turbine speed TREVO at the start of the shift, the larger the range of change in the turbine speed at the time of the shift, so that the engagement timing of the coast clutch 17 is kept constant during each shift. Then, the predicted speed after the shifting in step S ₆
TREV1 is added to the added rotation speed TREVB, and this rotation speed TREVA
(= TREV1 + TREVB) is defined as the fastening start rotation speed.

Thereafter, actual turbine speed TR again in step S ₇
Reads EV, the turbine speed TREV repeatedly comparing with the fastening start rotational speed TREVA in step S _8, TRE
When it becomes V <Treva, selects a control pattern of the solenoid valves 76 to 78 to the second intermediate position of the second table in step S _9. As a result, the release chamber 45b of the servo mechanism 45
In addition to applying the engagement pressure to the coast clutch 17 as shown in FIG. 5, the engagement pressure is supplied to the coast clutch 17 for engagement, thereby locking the first one-way clutch 16 and securing the effectiveness of the engine brake. After that, the third speed in the second table is selected, the fastening pressure is supplied to the apply chamber 45a of the servo mechanism 45 in advance by the ON operation of the first solenoid valve 76, and the process ends. The second intermediate position differs from the third speed in that no fastening pressure acts on the apply chamber 45a of the servo mechanism 45, but has the same gear ratio as the third speed.

On the other hand, in the increase condition of the engine load θ ≧ 1/32 in the step S _1, in order to delay only uniformly between setting the engagement time T of the coast clutch 17, Step S ₂ in Step S ₁₀
In after the control pattern of the solenoid valves 76 to 78 were selected in the first intermediate position of the second table, and selecting the second intermediate position at step S _11.

Therefore, in the control flow of FIG.
According to S ₁ , S ₂ , S _{7 to} S ₉ , when shifting to the third speed where the engine brake operates due to the decrease in the engine load at which the throttle valve opening θ is θ <1/32, First
The engagement of the coast clutch 17 (the friction element to be engaged at the third speed), which controls the effect of the engine brake by the operation of the one-way clutch 16, is performed by setting the delay time to until the actual turbine speed TREV becomes less than the set speed TREVA. Only for a while,
The delay means 155 is configured to correct the switching means 153 so as to be delayed by taking the first intermediate position in Table 2.

Further, in step S ₃ to S ₆ of the control flow, based on the actual turbine speed TREV at the shift start, set by adding the plus rpm TREVB obtained from Figure 4 the prediction rotational speed TREV1 after shifting rotation The above-mentioned delay means is determined so that the value TREVA is obtained, and the engagement of the coast clutch 17 is delayed until the actual turbine speed TREV becomes less than the set value TREVA.
The delay time setting means 156 is configured to set the set delay time to of 155.

Therefore, in the above-described embodiment, at the time of the 2 → 3 shift, as shown in FIG. 5, the action of the engagement pressure on the coast clutch 17 which governs the effect of the engine brake is reduced by the set delay time to.
The delay time to is set by adding the additional turbine speed TREVB obtained from FIG. 4 to the actual turbine speed TREV according to the operating state, ie, the set engine speed TREV1 after shifting. Since it is an appropriate time until the rotational speed TREVA is reached, the longitudinal acceleration G of the vehicle and the turbine rotational speed smoothly change as shown in FIG. Therefore, the coast clutch 17 can be fastened in the seventh
Internal lock in the case as shown in FIG. 1A is reliably prevented, a temporary decrease in the longitudinal acceleration G and a temporary decrease in the turbine speed can be eliminated, and shift shock can be effectively reduced. In the case where the coast clutch 17 is engaged relatively quickly as shown in FIG. 3B, it is possible to prevent a thrust shock (abrupt increase in the longitudinal acceleration G) and to delay the coast clutch 17 from engaging as shown in FIG. In the case shown in (1), a state in which the engine brake is not effective and the vehicle runs idle before the engagement, and a pull-in shock (a sudden decrease in the longitudinal acceleration G) at the time of the engagement can be prevented.

FIG. 6 shows another embodiment.
Instead of being applied at the time of the third shift, this is applied at the time of the 3 → 4 shift (each control of engagement → release of the coast clutch 17 and release / engagement of the 2-4 brake 18).

That is, as shown in Table 3, the solenoid valves 76 to
In the control pattern of 78, an intermediate position is added in addition to the third speed and the fourth speed, and when shifting from the third speed to the fourth speed, the set delay time to (TREV <TREVA) as shown in FIG. During this period, the intermediate position shown in Table 3 (the same as the first intermediate position shown in Table 2) is taken, and the engagement of the coast clutch 17 is immediately released. Is temporarily forcibly released from the engaged state of the 2-4 brake 18 (the state in which the applied pressure is acting on the apply chamber 45a of the servo mechanism 45), and when the delay time to elapses, The 2-4 brake 18 is re-engaged by applying a fastening pressure to the apply chamber 45a again.

Therefore, also in the present embodiment, the release operation of the coast clutch 17 and the engagement operation of the 2-4 brake 18 are appropriately performed between the two, and the internal lock due to the simultaneous engagement of the two can be reliably prevented, and 2-4 It is possible to effectively reduce the feeling of idling and pull-in shock of the vehicle due to a delay in the operation of engaging the brake 18.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a skeleton diagram of an automatic transmission, FIG. 2 is a hydraulic circuit diagram, and FIG.
FIG. 9 is a flowchart showing the control during the 2 → 3 shift, and FIG.
The figure shows the characteristic of the additional rotation speed with respect to the actual turbine rotation speed, FIG. 5 is an operation explanatory diagram, and FIG. 6 is an operation explanatory diagram showing another embodiment. FIG. 7 is an operation explanatory view showing a conventional example. 5 ... gear mechanism, 17 ... coast clutch, 18 ...
2-4 brake, 24 ... 3-4 clutch, 152 ... rotation speed sensor (rotation speed detecting means), 153 ... switching means, 155 ...
... delay means, 156 ... delay time setting means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 61/08

Claims (2)

(57) [Claims] The present invention has a one-way clutch provided in a transmission gear mechanism and a plurality of friction elements including a predetermined friction element provided in parallel with the one-way clutch for operating an engine brake. By switching the operation state, a plurality of speeds including the speed at which the engine brake operates are achieved, and at the time of shifting to the speed at which the engine brake operates, the gears are engaged before and after the speed change. Detects the input-side rotational speed of a transmission in an automatic transmission in which an internal lock is generated in a transmission gear mechanism when a plurality of friction elements and a predetermined friction element for applying an engine brake are simultaneously engaged. Rotation speed detecting means for performing a predetermined engagement when shifting to a gear position where the engine brake operates due to a decrease in engine load. And delay means for delaying the engagement of the frictional element from the time of the shift command until the input-side rotation speed of the transmission reaches a rotation speed having a predetermined relationship with the predicted input-side rotation speed at the end of the shift. A shift control device for an automatic transmission. And a plurality of friction elements including a one-way clutch provided in the transmission gear mechanism and a predetermined friction element provided in parallel with the one-way clutch for operating an engine brake. By switching the operating state, a plurality of speeds including the speed at which the engine brake operates are achieved, and at the time of shifting to the speed at which the engine brake operates, the gears are engaged at the speed before and after the speed change. The automatic transmission is configured such that an internal lock is generated in the transmission gear mechanism when a plurality of friction elements and a predetermined friction element for operating the engine brake are simultaneously engaged. A rotational speed detecting means for detecting, when shifting to a gear position where the engine brake operates due to a decrease in engine load, before shifting or In the state where the same gear ratio as the gear ratio of the post-speed gear stage is achieved, the input rotation speed of the transmission is changed to the predicted input rotation speed at the end of the shift from the time of the shift command to the engagement of the predetermined friction element to be engaged. And a delay means for delaying the rotation speed until the rotation speed has a predetermined relationship with respect to the transmission speed.