JPS6383436A - Automatic transmission for automobile - Google Patents

Abstract

PURPOSE:To permit a shock caused by a speed change and engine racing due to timing control to be eliminated, by effecting a speed change by bringing a first or second auxiliary clutch into a semi-engagement condition while keeping a main clutch in an engaging condition. CONSTITUTION:When a speed change mode is selected in traveling, a CPU 142 causes a main clutch 12 to be engaged at all times and an auxiliary clutch 58 which is not engaged is brought into a semi-engagement condition in response to an up-shift command so that output torque from a transmission 14 reduces to increase a load on an engine. As a result, a rotational speed Ne reduces and a sleeve 94 moves to a neutral position at a reduction start point where a rate of change of the rotational speed is smaller than a predetermined value -alpha. Then, when the speed Ne reduces to become a rotational speed wherein a second speed can be obtained at a present automobile speed, torque transmitted at a first gear position reduces and the sleeve 94 moves to a neutral position. next, when the speed Ne reduces to a target speed N1, the sleeve 94 is positioned at the side of a gear 40 and rotation of an intermediate shaft 31 is synchronized with that of a gear 40 by a synchronizing device 88 to cause the sleeve 94 to be engaged with the gear 40, whereby a gear position of the second speed is established.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an automatic transmission for a vehicle, and more particularly to a technique for preventing shift shock when switching gear pairs and for facilitating shift control.

Prior Art An input shaft connected to an engine via a main clutch, an output shaft connected to a drive wheel, and multiple types of gear pairs for transmitting the power of the input shaft to the output shaft at mutually different gear ratios. and a shift member operated to select the gear pair, and by automatically operating the shift member, the power transmitted from the engine is transmitted to the drive wheels at a desired gear ratio. A type of automatic transmission device for a vehicle is known. According to such a device, since a speed change gear mechanism similar to that of a conventional manual transmission is employed, there is an advantage that even when automatic speed change is performed, economical efficiency similar to that of a manual transmission can be obtained.

However, when such an automatic transmission shifts automatically, the amount of fuel supplied to the engine is reduced and the engine output is temporarily reduced according to a predetermined operating sequence similar to the manual gear shifting operation by the driver. At the same time, the main clutch connecting the input shaft of the stepped transmission and the engine is released, and then the actuator changes the gear stage of the stepped transmission, and the main clutch is again engaged. Ru.

For this reason, during the release period of the main clutch, that is, during the period in which power transmission from the engine is interrupted, there is a problem in that the shift feeling is slightly uneven. In particular, when shifting in a lower gear, such as an upshift from a first gear to a second gear, or from a second gear to a third gear, or vice versa, a downshift occurs. This inconvenience is significant because the difference between the drive torque of the transmission input shaft and the drive torque of the output shaft is large.

On the other hand, as described in Japanese Patent Application Laid-open No. 58-193951, for example, by providing a sub-clutch between the engine and the output shaft so as to be parallel to the main clutch, the main clutch can It has been proposed that while the clutch is released, the sub-clutch is in a semi-engaged state to transmit rotational energy of the engine to the drive wheels of the vehicle, thereby alleviating interruptions in power transmission during gear shifting.

Problems to be Solved by the Invention However, in such conventional automatic transmissions, the auxiliary clutch is arranged between the engine and the output shaft so that it is parallel to the main clutch, so that the speed change of the automatic transmission is difficult. In this case, the timing of switching between the engaged state of the main clutch and the auxiliary clutch is delicate, making control difficult. That is, if the secondary launch is engaged too quickly when the main clutch is released, the transmission will be locked, resulting in a heavy shift shock, and if it is too slow, the engine will rev up.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The gist of this is that the input shaft is connected to the engine via the main clutch, the output shaft is connected to the drive wheels,
The apparatus includes a plurality of types of gear pairs for transmitting the power of the input shaft to the output shaft at mutually different gear ratios, and a shift member operated to select the gear pairs, and the shift member is automatically operated. An automatic transmission for a vehicle of a type that transmits power transmitted from the engine to the drive wheels at a desired gear ratio by operating the vehicle, wherein (1) the first and second gears of the plurality of types of gear pairs are (2) an intermediate shaft including one of the gears constituting each of the second gear pair and provided in the power transmission path between the input shaft and the output shaft; (2) third and fourth gears of the gear pair; are provided in parallel with each other between the input shaft and the output shaft in order to control the transmission state of the power transmitted through the gear pairs, respectively, and establish gear stages corresponding to the first and second gear pairs, respectively. (3) a pair of first sub-clutches and a second sub-clutch that are selectively half-engaged to transmit power during a speed change, and (3) the intermediate shaft and the output shaft or the input shaft; and a one-way clutch that is provided between the two and transmits only power in the direction toward the output shaft.

Operation and Effects of the Invention In this way, the first sub-clutch or the second sub-clutch is provided between the input shaft and the output shaft and is connected in series with the main clutch. The gear shift is possible by keeping the main clutch in the engaged state and the first sub-clutch or the second sub-clutch in a semi-engaged state. The vehicle is driven by the power transmitted. As a result, for example, in a shift amplifier, while the decrease in acceleration feeling during gear shifting is alleviated,
When the engine rotational speed is reduced by engaging the sub clutch or the second sub clutch to such an extent that the one-way clutch slips, the gear pair that has been established up to that point is quickly switched to the next gear pair. Therefore, there is no need for delicate timing control between the main clutch and the auxiliary clutch, so the shift shock and engine revving caused by timing control are largely eliminated, and the control device is simplified. .

Further, in the present invention, the first sub-clutch or the second sub-clutch, which is selectively half-engaged when shifting to the gear stage corresponding to the first gear pair and the second gear pair, have a gear ratio that is different from each other. Since it is arranged to control the transmission state of the power transmitted through the third and fourth gear pairs of the different gear pairs, it is possible to reduce the variation width of the transmission output torque during gear shifting. In addition to being able to
The durability of the sub-clutch or the second sub-clutch is increased.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, power from a vehicle engine 10 is transmitted to drive wheels 18 via a first clutch 12, a parallel two-shaft synchronized mesh type stepped transmission 14, and a differential gear 16. The first clutch 12, the stepped transmission 14, the controller 122, and the like constitute the automatic transmission of this embodiment.

The first clutch 12 is a hydraulic main clutch that connects the crankshaft 20 of the engine 10 and the input shaft 20 of the transmission 14.
is provided between the crankshaft 20 and the damper 21.
A rotor 24 connected to the rotor 24 and a piston 26 that presses the rotor 24 when hydraulic pressure is applied thereto are housed in a shaft case 28.

The transmission 14 is for a front engine, front wheel drive (FF) vehicle, and includes a transmission mechanism similar to that conventionally known as a synchronous mesh manual transmission. Transmission 14
, an input shaft 22 and an output shaft 30 to which a cylindrical intermediate shaft 31 is fitted so as to be relatively rotatable are disposed in a housing 32 parallel to each other, and the input shaft 22 and the intermediate shaft 31 and the output shaft 30, a plurality of types of gear pairs that transmit power at mutually different reduction ratios are arranged. That is, in this embodiment, a first speed gear pair and a second speed gear pair are arranged between the input shaft 22 and the intermediate shaft 31, and between the input shaft 22 and the output shaft 30, A third speed gear pair, a fourth speed gear pair, a fifth speed gear pair, and a reverse gear device are provided.

That is, the first gear pair includes a first fixed gear 34 fixed to the input shaft 22 and a first rotary gear 36 rotatably supported by the intermediate shaft 31 while meshing with the first fixed gear 34. The second speed gear pair is a second gear pair fixed to the input shaft 22.
The intermediate shaft 3 is meshed with the fixed gear 38.
1, and a second rotary gear 40 rotatably supported by the input shaft 2, and the third speed gear pair is connected to the input shaft 2 via a second clutch 58.
A third rotary gear 42 is rotatably supported on the input shaft 22 so as to be able to engage and disengage from the intermediate shaft 3 and the output shaft 30 through a fourth clutch 62.
The third fixed gear 44 is fixed to the clutch case 64 so as to be able to engage and disengage from the input shaft 22 via the third clutch 60. a fourth rotatably supported on the input shaft 22;
The output shaft 3 is meshed with the rotating gear 46.
0, and the fifth gear pair is rotatably supported on the output shaft 30 while meshing with the fifth fixed gear 50 fixed to the input shaft 22. and a fifth rotary gear 52. Further, the reverse gear device includes a sixth fixed gear 54 fixed to the input shaft 22.
and a sixth rotating gear 55 rotatably supported by the output shaft 30, the sixth fixed gear 54, and the sixth rotating gear 55.
It consists of a reversing gear 56 meshed with.

As mentioned above, the second clutch 58 and the third clutch 6
0 is provided in the power transmission path passing through the third speed gear pair and the power transmission path passing through the fourth speed gear pair, respectively, and is positioned in series with the first clutch 12.

The second clutch 58 corresponds to the first sub-clutch in this embodiment, and is the rotor 6 fixed to the input shaft 22.
6, a piston 68 that presses the rotor 66 when hydraulic pressure is applied thereto, and a clutch case 70 that accommodates the pistons 68 and is fixed to the third rotating gear 42 so as to be relatively rotatably supported by the input shaft 22. It is equipped with The third clutch 60 corresponds to a second sub-clutch in this embodiment, and is a rotor 72 fixed to the input shaft 22.
, a piston 74 that presses the rotor 72 when hydraulic pressure is applied thereto, and a clutch case 76 that accommodates the pistons 74 and is fixed to the fourth rotating gear 46 so as to be relatively rotatable to the input shaft 22. We are prepared. The second clutch 58 and the third clutch 60 establish the third gear stage and the fourth gear stage, respectively, by their engagement action, and also by their engagement action, during the switching of other gear stages. Eliminate power transmission interruptions.

The fourth clutch 62 is for engine braking, and is connected to an intermediate shaft rotor 78 fixed to the intermediate shaft 31 and an output shaft rotor 80 fixed to the output shaft 30 by applying hydraulic pressure thereto. A clutch case supported by the output shaft 30 via a piston 82 that presses the intermediate shaft rotor 78 and the output shaft rotor 80, and a one-way clutch 84 that houses them and transmits only power in the direction toward the output shaft 30. 64. Output shaft 3
A one-way clutch 86 that only transmits power in the direction toward the output shaft 30 is also provided between the output shaft 30 and the intermediate shaft 31 . That is, the fourth clutch 62, one-way clutch 84, and one-way clutch 86 are arranged in parallel between the intermediate shaft 31 and the output shaft 30 in the power transmission direction of the engine 10.

The fourth clutch 62 configured as described above has its piston 82 connected to the intermediate shaft rotor 78 and the output shaft rotor 8.
By pressing 0, the output shaft 30, intermediate shaft 31, and third fixed gear 44 are fixed to each other. This prevents the idling action of the one-way clutch 84 and the one-way clutch 86 in a state where power is transmitted through any of the first to third gears, thereby generating an engine braking action.

The first rotary gear 36 and the second rotary gear 40 are selectively engaged with the intermediate shaft 31 so that they cannot rotate relative to each other by a first synchronizer 88 provided on the intermediate shaft 31. Further, the fifth rotating gear 52 and the sixth rotating gear 55
Similarly, the second synchronizer 89 provided on the output shaft 30
Alternatively, it can be engaged with the output shaft 30 in a relatively non-rotatable manner.

The first synchronizer 88, as shown in FIG.
a hub 90 fixed to the hub 90; a first sleeve 94 spline-fitted to the hub 90 and driven in the axial direction by the first hydraulic cylinder 92; A key 96 provided, a spring 98 that biases the key 96 toward the outer circumference, and a first
Peripheral teeth 100 and 102 formed on the rotary gear 36 and the second rotary gear 40, respectively, and synchronization rings 104 and 104 disposed between the first sleeve 94 and the first rotary gear 36 and the second rotary gear 40, respectively. 106. The first hydraulic cylinder 92 causes the first sleeve 94 to
For example, when the synchronizing ring 104 is moved toward the first rotating gear 36, the synchronizing ring 104 is pressed against the first rotating gear 36 via the key 96. Then, when the rotations of the hub 90 and the first rotary gear 36 are synchronized by mutual friction between the conical friction surfaces 108 and 110 formed on the first rotary gear 36 and the synchronization ring 104, the rotation of the first sleeve 94 is further synchronized. Movement is allowed, and the inner teeth of the first sleeve 94 and the outer teeth 100 of the first rotary gear 36 mesh with each other. As a result, the first gear stage is established. On the contrary, the first sleeve 94 is moved toward the second rotating gear 40 and
When the outer peripheral teeth 102 of the rotating gear 40 are meshed,
The second gear stage is established.

The second synchronizer 89 is also configured in the same manner as the first synchronizer 88, and is spline-fitted to the hub 112 fixed to the output shaft 30 and driven in the axial direction by the second hydraulic cylinder 114. A sleeve 116 is provided. When the second sleeve 116 is engaged with the fifth rotating gear 52, a fifth gear is established, and when it is engaged with the sixth rotating gear 55, a reverse gear is established.

The engine 10 is provided with an engine rotation sensor 120 for detecting its rotation speed.
A rotation signal SR corresponding to a rotation speed Ne of 0 is supplied to the controller 122. The accelerator pedal 124 of the vehicle includes an accelerator sensor 1 for detecting the operation 1Acc.
26 is provided, and an accelerator signal SA representing the accelerator operation amount Acc is supplied to the controller 122.

A vehicle speed sensor 128 is provided near the output shaft 30, and a signal S■ corresponding to the rotational speed of the output shaft 30, that is, the vehicle speed V, is supplied to the controller 122. Input shaft 1
An input shaft rotation sensor 130 is provided near the input shaft 8, and a signal SI corresponding to the rotation speed Ni of the input shaft 22 is supplied to the controller 122. The transmission 14 is provided with a gear position sensor 132 for detecting the actual gear position, and a signal SG representing the actual gear position is sent to the controller 12.
2. Furthermore, the shift operation lever 13 of the vehicle
4 includes an operation position sensor 1 for detecting the operation position.
36. A signal SL indicating the operating position of the shift lever 134 is supplied to the controller 122.

The controller 122 includes a RAM 138, a ROM 140,
It is a so-called microcomputer that includes a CPU 142, an input interface 144, an output interface 146, etc., and utilizes the storage function of the RAM 138.
Processes the input signal according to a program stored in advance in the M140 and supplies a drive signal BD to the throttle actuator 148, as well as the first clutch 12,
The electromagnetic valves 152, 154, 156, . 15
7, 158, and 159 respectively. This hydraulic control circuit 150 includes a hydraulic pump (not shown) driven by the engine 10 or the like, and includes a solenoid valve 152.1.
54, 156, 157, 158, 159, the hydraulic pressure is applied to the first clutch 12, second clutch 58, third clutch 60, first hydraulic cylinder 92, second hydraulic cylinder 114, and fourth clutch 62. Supply each.

The first hydraulic cylinder 92 and the second hydraulic cylinder 114 have large diameter pistons 160 and 161 that are slidably fitted into a large diameter portion of a stepped cylinder bore, and large diameter pistons 161 that are slidably fitted into a small diameter portion of a stepped cylinder bore. It also includes small-diameter pistons 164 and 165 fixed to cylinder rods 162 and 163, respectively, and when hydraulic pressure is applied to the large-diameter portions, the cylinder rods 162 and 163
is pushed out the most, and by applying hydraulic pressure to the small diameter portion, the cylinder rods 162 and 163 are retracted the most, and by applying hydraulic pressure to the large diameter portion and the small diameter portion, the cylinder rods 162 and 163 are brought to the neutral position. It is designed to be positioned. As a result, for example, the first hydraulic cylinder 92 moves the first sleeve 94 to the neutral position, to the position on the first rotating gear 36 side, to the second rotating gear 4
Positioning is performed via the shift fork 166 to the third position of the zero example position. Similarly, the second hydraulic cylinder 114 positions the second sleeve 116 to three positions via the shift fork 167.

Throttle valve 16 provided in the intake pipe of engine 10
8 is adapted to be driven by the throttle actuator 148, and normally the accelerator is operated according to the drive signal BD from the controller 122 ff1Ac.
It is positioned so that the throttle valve opening degree θ corresponds to c. The solenoid valves 152 and 154 each have a first
It is for driving the hydraulic cylinder 92 and the second hydraulic cylinder 114, and when in operation, supplies the hydraulic pressure for obtaining a predetermined gear stage of the transmission 14 to the corresponding hydraulic cylinder. Further, the electromagnetic valves 156, 157, and 158 respectively control the engagement of the first clutch 12, the second clutch 58, and the third clutch 60, and when activated, keep the clutches engaged or semi-engaged. Supply hydraulic pressure for Furthermore, the electromagnetic valve 159 is for controlling the engagement of the fourth clutch 62, and when activated, it is kept in the engaged state and oil pressure for applying the engine brake is supplied.

The operation of this embodiment will be explained below.

In the controller 122, the CPU 142 selects a control mode such as start control, neutral control, shift control, engine brake control, etc. in accordance with vehicle condition parameters. When the shift control mode is selected while the vehicle is running, the CPU 142 operates the electromagnetic valve 156 so that the first clutch 12 is always engaged. Further, when the engine brake control mode is selected, the solenoid valve 159 is operated to engage the fourth clutch 62.

In the above-mentioned shift control, the CPU 142 selects a shift pattern corresponding to the current gear from a plurality of types of shift patterns (shift diagrams) stored in advance in the ROM 140, and uses the shift pattern to adjust the vehicle speed, accelerator operation amount, etc. Based on this, a shift command is issued to obtain the required gear stage. In such a case, a shift is automatically performed from the current gear to the commanded predetermined gear in a predetermined order. For example, if an upshift command is issued while driving in the first gear, a shift to the second gear is automatically executed according to the series of steps shown in FIG. When an upshift command is issued while the vehicle is running in the second gear, a shift to the third gear is automatically executed in accordance with a series of steps shown in FIG. Additionally, if a downshift command is issued while driving in 2nd gear, a shift to 1st gear is automatically executed according to the series of steps shown in Figure 5, and when driving in 3rd gear. When a downshift shift command is issued during 1. A shift to second gear is automatically performed according to the series of steps shown in FIG. In the above shift operation, the throttle valve opening θ and the engaged state of the first clutch 12 are maintained as they are.

For example, when an upshift command is issued from the first gear to the second gear, step 5UII in FIG. Oil supply begins. Point A in FIG. 7 shows this state. As a result, the second clutch 58 is brought into a half-engaged state, so the output torque of the transmission 14 decreases, the load on the engine 10 increases, and the engine rotational speed Ne starts to decrease. Point B in FIG. 7 shows this state. In step 5U12, the rate of change in engine rotational speed (dNe/dt) is set to a predetermined value -α
The point at which the engine rotational speed Ne starts to decrease, that is, the above-mentioned point B, is determined based on whether or not the engine speed Ne is smaller than . When the point at which the engine rotational speed Ne starts to decrease is determined in step 5U12, step 5U13 is executed, and the hydraulic pressure for moving the first sleeve 94 to the neutral position is reduced to t.
m valve 152 to the first hydraulic cylinder 92, and the first
Sleeve 94 moves to the neutral position.

Then, step 3014 is executed and the second clutch 5
Hydraulic pressure to 8 is maintained. As a result, the engine rotational speed Ne is continuously reduced. During this period, the output torque of the transmission 14 is slightly increased by the inertia energy of the engine 10, and when the engine rotational speed Ne substantially matches the rotational speed obtained in the second gear at the current vehicle speed, the first gear is shifted. The torque transmitted through the stage is reduced and the first sleeve 94 is moved to a neutral position.

In step 5U15, the target rotational speed N1' corresponding to the first gear stage and the actual vehicle speed is selected from a plurality of pre-stored relationships, and the actual engine rotational speed Ne is set to the target rotational speed N,'' This target rotational speed NI' is determined to be slightly lower than the engine rotational speed that should be obtained when the vehicle runs at the current vehicle speed at the gear ratio of the next gear, 2nd speed. For example, the ROMI 40 stores in advance a relational expression for determining the engine rotational speed obtained when the next gear to be shifted is established, and in step 5U15, the current The target rotational speed N1' is calculated based on the gear position and the current vehicle speed.

When it is determined in step 5U15 that the actual engine rotation speed Ne has decreased to the target rotation speed N11, step 5U16 is executed and the first hydraulic cylinder 92
By operating the cylinder rod 162, the first
A biasing force is applied to position the sleeve 94 from the neutral position toward the second rotating gear 40 side. Point 0 in FIG. 7 indicates this state.

As a result, the first synchronizer 88 performs a synchronous operation, and the rotations of the intermediate shaft 31 and the second rotary gear 40 are synchronized.

During this period, the actual engine rotational speed Ne is maintained slightly lower than the target rotational speed N,1, so the one-way clutch 86 acts, and the synchronization between the intermediate shaft 31 and the second rotating gear 40 is smoothly performed. As a result, the first sleeve 94 is positioned from the neutral position toward the second rotating gear 40 side.

In step 5U17, when it is determined that the engagement between the first sleeve 94 and the second rotary gear 40 is completed and the second gear stage is established, step 5U18 is executed to supply the second clutch 58 with the first sleeve 94 and the second rotating gear 40. The hydraulic pressure that was being used is exhausted. As a result, as shown at point D in FIG. 7, the engine rotational speed Ne starts to increase and the transmission torque of the second clutch 58 starts to decrease. When the transmitted torque becomes zero, the power is transmitted exclusively through the second gear pair, the first synchronizer 88, and the one-way clutch 86, so the engine rotational speed Ne corresponds to the second gear. At the same time, the output torque of the transmission 14 becomes T2. here,
The time from point A to point E in FIG. 7 is about 0.4 seconds. Further, T in FIG. 7 is the output torque of the transmission 14 when power is transmitted by the first gear pair, and T
2 is the output torque of the transmission 14 when the power is transmitted by the second gear pair, and T3 is the output torque of the transmission 14 when the power is transmitted by the third gear pair. be.

When a shift command for upshifting to third speed is issued while the vehicle is running in second speed, the gear stage is automatically changed according to the procedure shown in FIG. That is, step SU21
is executed, hydraulic pressure is supplied to the third clutch 60, and engagement thereof is started. Therefore, the engine 100 rotational speed Ne starts to decrease. When this decrease in the rotational speed Ne of the engine 10 is determined in step SU22, which is similar to step 5U12, step 5U23 is executed to supply hydraulic oil to the first hydraulic cylinder 92 and move the first sleeve 94 to its neutral position. At the same time, step SU24 is executed and the oil pressure of the third clutch 60 at that time is maintained. Then, step 5U
Step SU25 similar to Step 15 is executed to determine a target rotational speed NZ" which is slightly lower than the engine rotational speed that should be obtained in the third gear at the current vehicle speed, and at the same time, the actual engine rotational speed Ne is set to the target rotational speed. It is determined whether the engine speed has decreased to N%. If it is determined in this step 5U25 that the actual engine rotation speed Ne has decreased to the target rotation speed NZ'', the second clutch 58 is engaged in step SU26. After that, the third clutch 60, which had been in the half-engaged state until then, is released from the half-engaged state in step SU27.

As described above, in this embodiment, when an upshift command is issued while driving in the first gear or the second gear, the power transmission path passing through the third gear pair is changed. The inserted second clutch 58 or the third clutch 60 inserted in the power transmission path passing through the fourth speed gear pair is half-engaged, and the power transmission during the gear change period of the stepped transmission 14 is controlled. Since no interruptions occur, a suitable shift feeling can be obtained.

In this embodiment, the second clutch 54 is partially engaged while the first clutch 12 is in the engaged state, and the engine rotational speed is lowered than the target rotational speed NI* to cause the one-way clutch 86 to slip slightly. Since the second gear stage is established in the state where the second gear is set, there is no need for delicate timing control between the first latch 12 and the second clutch 54, and the shift shock and engine revving caused by the timing control are completely eliminated. This also simplifies the control device.

In addition, when upshifting from the first gear to the second gear, the torque due to the half-engagement of the second clutch 58 is transmitted at the gear ratio of the third gear, so the torque is transmitted at the gear ratio of the fourth gear. Compared to the case where torque is transmitted, there are advantages that the output torque fluctuation range of the transmission 14 is reduced and the durability of the second clutch 58 is improved.

On the other hand, for example, if a downshift command is issued while driving in second gear, step 5D11 in FIG.
The supply of hydraulic oil to is started. A' in FIG. 8 shows this state. As a result, the second clutch 58 is brought into a semi-engaged state, so that when the power of the engine 10 is transmitted through it, the power transmitted through the first synchronizer 88 starts to decrease compared to before. At the same time, the load on the engine 10 increases and the engine rotational speed Ne starts to decrease. Bo in FIG. 8 shows this state.

In step 5D12, the rate of change of engine speed (
When it is determined that the engine rotational speed Ne has decreased based on the fact that dNe/dt) has fallen below a predetermined constant value -β, step 5DI3 is executed, and until then, the engine rotation speed Ne is located on the second rotating gear 40 side. Hydraulic pressure for moving the first sleeve 94, which has been in use, to the neutral position is supplied from the solenoid valve 152 to the first hydraulic cylinder 92. As mentioned above, the engine rotational speed has already been lowered from the rotational speed of the second speed, and the operation of the one-way clutch 86 causes the first synchronizer 8
Since no load is applied to 8, the first sleeve 94
is smoothly moved to its neutral position. Then, by executing step 5D14, the second clutch 5
At the same time, the pressure reduction of the hydraulic pressure supplied to the solenoid valve 15 is started, and the hydraulic pressure for moving the first sleeve 94, which has been in the neutral position until then, toward the first rotating gear 36 is supplied to the solenoid valve 15.
2 to the first hydraulic cylinder 92. C in Figure 8
The ° point indicates this state.

As a result of weakening the half-engaged state of the second clutch 58, the load on the engine is reduced, and the engine rotational speed Ne is increased to a rotational speed corresponding to the first gear stage. In the process, the first sleeve 94 is moved toward the first rotary gear 36 to establish the first gear stage, and then the one-way clutch 86 is engaged. Point D' in FIG. 8 shows this state. When this state is determined in step 5D15, step 5D16 is executed and the hydraulic pressure supplied to the second clutch 58 is exhausted. As a result, the transmission torque of the second clutch 58 starts to be further reduced, and when the release of the second clutch 58 is completed as shown at point E' in FIG. 1 synchronizer 88
Since the power is transmitted through the transmission 14, the output torque of the transmission 14 is T. Here, T1 in FIG. 8 is the output torque of the transmission 14 when power is transmitted by the first speed gear pair.

If a downshift command is issued while the vehicle is running in third gear, gear changes are automatically executed in the order shown in FIG. That is, Ste-knob 5D21 is executed and the second
The holding hydraulic pressure of the clutch 58 is reduced, and the first sleeve 94 is urged from the neutral position toward the second rotating gear 40 by the first hydraulic cylinder 92. When the load applied to the engine 10 is reduced as the engagement of the second clutch 58 is weakened, the engine rotational speed Ne
increases and reaches the rotational speed that should be obtained in the second speed at the current vehicle speed, so that the first sleeve 94 has moved and meshed with the second rotary gear 40 by now. When such meshing between the first sleeve 94 and the second rotary gear 40 is determined in step SD22, step 5D23 is executed, and the supply of hydraulic pressure to the second clutch 58 is released to release its engagement. It will be destroyed.

In this way, when a downshift shift command is issued while driving in the second or third gear, power is transmitted during the gear shift period of the stepped transmission 14, as in the case of an upshift. No interruptions occur. Further, in this embodiment as well, since the gear shift of the transmission 14 is executed by changing the engagement state of the second clutch 58 while the first clutch 12 is in the engaged state, the first clutch 12 and the second clutch This eliminates the need for delicate timing control when switching between the 5-day and 5-day maintenance states, and the shift shock and engine revving caused by the timing control are largely eliminated, and the control device becomes simpler.

In the amplifier shift from the third speed to the fourth speed, the throttle valve 168 is closed and the engagement hydraulic pressure of the second clutch 58 is released according to the control operation of the controller 122, and then the engagement hydraulic pressure is applied to the third clutch 60. The throttle valve 168 is returned to its original position. Fourth
In the amplifier shift from speed to fifth speed, the controller 12
2, the throttle valve 168 is closed and the locking hydraulic pressure of the third clutch 60 is released, and then the second hydraulic cylinder 114 releases the second sleeve 1.
16 is meshed with the fifth rotary gear 52. In this way, when upshifting from third gear to fourth gear and from fourth gear to fifth gear, the throttle valve 168 is temporarily closed and power transmission is interrupted. Since the transmission gear ratio is small and the driving force of the vehicle is small, interruption of power transmission does not pose a practical problem. Note that in downshifting from the fifth speed to the fourth speed and from the fourth speed to the third speed, operations in reverse to the above are automatically and sequentially executed.

If it is determined that engine braking is necessary based on parameters such as road slope, vehicle speed, and amount of accelerator operation,
According to the control operation of the controller 122, the solenoid valve 1
59 supplies hydraulic pressure to the fourth clutch 62 for engine braking, and the intermediate shaft 31 and output shaft 30 are coupled together. As a result, the one-way power transmission operation of one-way clutches 84 and 86 is prevented, and an engine braking effect occurs.

As described above, according to this embodiment, when shifting between low speed gears of the transmission 14, the first clutch 12 is in the engaged state and the second clutch 58 is in the half-engaged state, so that multiple types of Since the gear pair is switched, delicate timing control between the first clutch 12 and the second clutch 58 is not required.

Therefore, the shift shock and engine revving caused by the timing control can be largely eliminated, and the control device can be simplified.

Further, according to this embodiment, one-way clutches 84 and 8
6, unless the fourth clutch 62 is operated, good coasting can be obtained in low gears below 3rd gear, improving economic efficiency, and when engine braking is required, There is an advantage that the fourth clutch 62 is automatically operated to provide a braking action.

Further, according to this embodiment, the second clutch 58 is provided on the third speed gear pair, and the third clutch 60 is provided on the fourth speed gear pair, so that the second clutch 58 is provided on the third speed gear pair and the third clutch 60 is provided on the fourth speed gear pair. Since the second clutch 58 is controlled to be half-engaged during an upshift, and the third clutch 60 is controlled to be half-engaged during an upshift from the second speed to the third speed, a relatively large driving force can be obtained during the shift.

Therefore, the fluctuation width of the output torque of the transmission 14 is reduced, and the sudden shift feeling is improved, and the second clutch 58
Also, there is an advantage that the slippage of the third clutch 60 is reduced and the durability thereof is improved.

Next, another embodiment of the transmission 14 will be described. In the following description, parts common to those in the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In the transmission 14 shown in FIG. 9, a seventh rotary gear 170 is rotatably supported on the input shaft 22, and a seventh fixed gear 172 that meshes with the seventh rotary gear 170 is fixed to the output shaft 30. . The seventh rotary gear 170 and the seventh fixed gear 172 are used exclusively to transmit power during shifting between the first speed and the second speed, and their speed ratio is the same as the speed change of the second speed gear pair. The number of teeth is determined to be an intermediate value between the gear ratio and the gear ratio of the third gear pair. By being fixed to the seventh rotating gear 170, the second clutch 58 is inserted into the power transmission path passing through the gear pair consisting of the seventh rotating gear 170 and the seventh fixed gear 172. In addition, in this embodiment, the third fixed gear 44 and the third rotating gear 42, the sixth fixed gear 54, the reversing gear 56,
and the sixth rotary gear 55 are connected to the input shaft 22 and the intermediate shaft 31.
A third synchronizer 176 is disposed between the third rotary gear 4 and driven by the third hydraulic cylinder 174.
The second or sixth rotating gear 55 and the intermediate shaft 31 are selectively engaged.

According to this embodiment, when shifting between the first speed and the second speed, the transmitted torque due to the half-engagement of the second clutch 58 is transmitted to the gear pair consisting of the seventh rotary gear 170 and the seventh fixed gear 172. As a result, the transmission torque during gear shifting is further increased compared to the above-described embodiment, and the output torque fluctuation range during gear shifting of the transmission 14 is suitably reduced, and the output torque of the second clutch 58 is This has the advantage of further increasing durability.

Although one embodiment of the present invention has been described above based on the drawings,
The invention also applies in other aspects.

For example, in the embodiment shown in FIG. 1, the intermediate shaft 31 is fitted to the outer periphery of the output shaft 30 so as to be relatively rotatable, but it may also be fitted to the outer periphery of the input shaft 22.

In this case, between the intermediate shaft 31 and the output shaft 30 there are multiple types of gear pairs, one-way clutch 8, and fourth clutch 6.
2 is arranged.

Further, in the transmission 14 shown in FIG. 1 described above, for example, the synchronizing device 88 for selectively engaging the intermediate shaft 31 and the first rotating gear 36 or the second rotating gear 40 has a synchronizing function. Although synchronization rings 104 and 106 are provided to generate the synchronization, the synchronization rings 104 and 106 are not necessarily provided, since synchronization is enabled by half-engagement of the second clutch 58.

Note that the above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the configuration of an embodiment of the present invention. FIG. 2 is a diagram illustrating the structure of the synchronization device shown in FIG. 1. 3 and 4 are flowcharts respectively illustrating operations during upshift in the embodiment of FIG. 1. 5 and 6 are flowcharts respectively illustrating operations during downshift in the embodiment of FIG. 1. FIG. 7 is a diagram illustrating changes in engine rotational speed and transmission output torque during the operation of FIG. 3. FIG. 8 is a diagram illustrating changes in engine rotational speed and transmission output torque during the operation of FIG. 5. FIG. 9 is a schematic diagram showing another example of the configuration of the transmission. 10: Engine 12: First clutch (main clutch) 14: Transmission 18: Drive wheel 22: Input shaft 30: Output shaft 31: Intermediate shaft 58: Second clutch (first sub clutch) 60: Third clutch (first clutch) 2 auxiliary clutch) 62: 4th clutch 84. 86F one-way clutch Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (1)

[Scope of Claims] An input shaft connected to the engine via a main clutch, an output shaft connected to the driving wheels, and a plurality of input shafts for transmitting the power of the input shaft to the output shafts at mutually different gear ratios. and a shift member operated to select the gear pair, and by automatically operating the shift member, the power transmitted from the engine is driven at a desired gear ratio. The automatic transmission for a vehicle is of a type in which transmission is transmitted to a wheel, and includes one of the gears constituting each of the first and second gear pairs of the plurality of types of gear pairs, and wherein the input shaft and the output shaft are connected to each other. an intermediate shaft provided in a power transmission path between the input shaft and the output shaft for controlling the transmission state of power transmitted through the third and fourth gear pairs of the gear pairs, respectively; A pair of first gears are provided in parallel with each other and are selectively semi-engaged during gear changes to establish gear stages corresponding to the first and second gear pairs, thereby transmitting power during gear changes. A one-way clutch that is provided between the intermediate shaft and the output shaft or the input shaft and that transmits only power in the direction toward the output shaft. Automatic transmission for vehicles.