JPH034788B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a speed change control device for an automatic transmission.

(b) Prior Art There is an automatic transmission with four forward speeds, such as the one proposed in Japanese Patent Application No. 199316/1983. This automatic transmission has a one-way clutch, a forward clutch connected in series with the one-way clutch, and an overrunning clutch connected in parallel with the one-way clutch and the forward clutch. The forward clutch operates in all forward gears, i.e. 1st and 2nd gears.
It is engaged in 3rd gear, 3rd gear, and 4th gear. The one-way clutch is engaged in first, second and third gears, but is free in fourth gear. On the other hand, the overrunning clutch is not engaged in the D range, but is engaged in first, second, and third gears when engine braking is required. Therefore,
In the first, second and third speeds in the D range, rotational force is always transmitted via the forward clutch and one-way clutch. With such a configuration, the timing of shifting between the third speed and the fourth speed can be easily adjusted.

(c) Problems to be solved by the invention However, in the case of automatic transmissions as described above,
Since rotational force is always transmitted through a one-way clutch when shifting between 1st, 2nd, and 3rd gears, upshifting is particularly important when the throttle is fully closed, i.e., from 1st to 2nd gear. 1st gear →
There is a problem in that the one-way clutch generates a striking sound when changing from 3rd gear to 2nd gear to 3rd gear. That is, in the case of the above-described shift, when the shift is started, the engine rotational speed begins to decrease, and at the same time, the torque acting on the one-way clutch disappears, and the one-way clutch becomes free. Next, when the engine rotational speed decreases to a state corresponding to the target gear position, torque is temporarily applied to the one-way clutch, and then, when the gear shift is completed, the coasting state is established, so that the one-way clutch becomes free again. FIG. 7 shows how each element changes during such a shift.
As mentioned above, torque is temporarily applied to the one-way clutch which is in a free state during gear shifting, so an impact is applied to the one-way clutch and a striking sound is generated. This impact sound is unfavorable in terms of driving feeling. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by temporarily engaging a clutch provided in parallel with the one-way clutch during gear shifting. That is, the shift control device for an automatic transmission according to the present invention includes an upshift determination means for determining whether an upshift shift is started while the first clutch (forward clutch 22) is engaged, and an upshift determination means for determining whether an upshift shift is to be started while the first clutch (forward clutch 22) is kept engaged; Throttle fully closed detection means detects that the throttle is fully closed, and upshift determining means determines that the upshift shift is started, and throttle fully closed detection means (throttle fully closed switch 44) detects that the throttle is fully closed. When this occurs, the solenoid drive means operates the solenoid 32 for a predetermined period of time in a direction to engage the second clutch (overrunning clutch 24). Note that the inside brackets indicate corresponding members of the embodiments described later.

(e) Operation When the upshift determining means determines that a predetermined upshifting is to be started, and the throttle fully closed detecting means detects that the throttle is fully closed, the solenoid is turned on by the solenoid driving means, for example, The second clutch is engaged. When the second clutch is engaged, the rotational force is transmitted without passing through the one-way clutch, which is the same state as when the one-way clutch is engaged, and even if the direction of torque is reversed during gear shifting. The one-way clutch does not change from the free state to the fastened state, and the generation of impact noise is prevented.

(F) Embodiments Examples of the present invention will be described below with reference to FIGS. 2 to 6 of the accompanying drawings.

Figure 2 shows 4 forward speeds and 1 reverse speed with overdrive.
The power transmission mechanism of the automatic transmission is shown as a skeleton diagram. This power transmission mechanism includes a torque converter 10
an input shaft 13 to which the rotational force from the engine output shaft 12 is transmitted, an output shaft 14 to transmit the driving force to the final drive device, a first planetary gear set 15,
It has a second planetary gear set 16, a reverse clutch 18, a high clutch 20, a forward clutch 22, an overrunning clutch 24, a low and reverse brake 26, a band brake 28, a row one-way clutch 29, and a forward one-way clutch 30. . Incidentally, the torque converter 10 includes a lock-up clutch 11. The first planetary gear set 15 includes a sun gear S1,
It is composed of an internal gear R1 and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1 at the same time.The planetary gear set 16 also includes a sun gear S2 and an internal gear R.
2, and a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. Carrier PC1 is High Clutch 2
0, and the sun gear S1 can be connected to the input shaft 13 via a reverse clutch 18. The carrier PC 1 is connected via a forward clutch 22 and a forward one-way clutch 30 connected in series to the forward clutch 22.
Alternatively, it can also be connected to the internal gear R2 via an overrunning clutch 24 arranged in parallel to the forward clutch 22 and the forward one-way clutch 30. Sun gear S2 is always connected to input shaft 13, and internal gear R1 and carrier PC2 are always connected to output shaft 14. Low and reverse brake 2
6 can fix the carrier PC1,
Further, the band brake 28 can fix the sun gear S1. Row one way clutch 2
9 is the normal rotation of carrier PC1 (engine output shaft 1
Rotation in the same direction as 2) is allowed, but reverse rotation (rotation in the opposite direction to forward rotation) is not allowed.

The power transmission mechanism includes clutches 18, 20, 2
2 and 24 and brakes 26 and 28 in various combinations, the planetary gear set 15
and each of the 16 elements (S1, S2, R1, R2,
The rotational state of PC1 and PC2) can be changed, thereby making it possible to variously change the rotational speed of the output shaft 14 relative to the rotational speed of the input shaft 13. By operating the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in combination as shown in FIG. 3, four forward speeds and one reverse speed can be obtained. In addition, the circles in FIG. 3 indicate the clutches and brakes in operation, and α1 and α2 are the ratios of the number of teeth of sun gears S1 and S2 to the number of teeth of internal gears R1 and R2, respectively.
Further, the gear ratio is the ratio of the rotation speed of the input shaft 13 to the rotation speed of the output shaft 14.

FIG. 4 shows a device for controlling engagement and release of the overrunning clutch 24. The operation of the overrunning clutch 24 is controlled by the hydraulic pressure supplied by a hydraulic switching valve 34 which is switched by a solenoid 32. That is, line pressure oil passage 3
The overrunning clutch 24 is engaged by supplying a hydraulic pressure of 6 to the overrunning clutch 24, and the overrunning clutch 24 is released by cutting off the supply of hydraulic pressure. The solenoid 32 is turned on and off by signals from a control unit 38 constituted by a microcomputer. Signals from a vehicle speed sensor 40, a throttle opening sensor 42, and a throttle fully closed switch 44 are input to the control unit 38. Clutches other than the overrunning clutch 24, valves for controlling hydraulic pressure of brakes, etc. are not directly related to the present invention, and therefore their explanations are omitted.

The control unit 38 executes control as shown in FIG. First, the throttle opening signal is read from the throttle opening sensor 42 (step 100), then the vehicle speed signal is read from the vehicle speed sensor 40 (step 102), and then the read throttle opening signal and vehicle speed signal are used for preset shifting. Compare with the pattern and determine the appropriate gear position for the current driving condition (same 1
04). Next, it is determined whether the determined gear position matches the current actual gear position, that is, whether a gear change is necessary (step 106). If a shift is not required, the current operating state is maintained (step 108) and the process returns. If shifting is not required, the type of shifting is identified (110). That is, it is determined whether the transmission is a 1-2 shift, a 2-3 shift, a 3-4 shift, or the like. Then,
A shift command signal is output in accordance with the identified shift type (step 111). Next, it is determined whether the commanded shift is 1-2 shift, 1-3 shift, or 2-3 shift (step 112), and if the shift is other than the above, the process returns; It is determined whether the throttle fully closed switch 44 is turned on (step 114). When the throttle fully closed switch 44 is off, the process returns, and when the throttle fully closed switch 44 is on, a signal that turns on the solenoid 32 is output for a predetermined time t (step 116).

As a result, when the above control performs one of the 1-2, 1-3, and 2-3 gear shifts, and the throttle is fully closed, the solenoid 32
is turned on for a predetermined time t, and hydraulic pressure is supplied to the overrunning clutch 24. This causes the overrunning clutch 24 to be engaged for a predetermined time t. When the overrunning clutch 24 is engaged, rotational force is transmitted through it, and the one-way clutch is in the same state as if it were engaged. Therefore, even if the direction of torque transmission changes during gear shifting, the torque is transmitted through the overrunning clutch 24, so the one-way clutch does not change from the free state to the engaged state, and the generation of impact noise is prevented. The on/off state of the solenoid 32 during gear shifting, the change in engine speed, the change in torque, the relative rotation between the inner race and the outer race of the forward one-way clutch 30, the oil pressure state of the overrunning clutch 24, etc. It is shown in FIG. Overrunning clutch 24
Since the inner race and the outer race do not rotate relative to each other during gear shifting, no impact noise is generated even if the torque transmission direction changes. This becomes clear when compared with that shown in FIG. 7 above.

Note that the predetermined time t for turning on the solenoid 32 during gear shifting can be constant for all three gear shifts, or can be set at an appropriate time for each gear shift, or can be set according to driving conditions such as vehicle speed. It can also be made variable. Further, in this embodiment, the throttle fully closed state is detected using the throttle fully closed switch 20, but when the throttle opening detected by the throttle opening sensor 42 is less than a predetermined value, the throttle is fully closed. It is also possible to determine that.

(G) Effects of the Invention As explained above, according to the present invention, when the throttle is fully closed during upshifting between gears in which the one-way clutch is applied, the clutch disposed in parallel with the one-way clutch is Since the clutch is fastened, it is possible to prevent one-way clutch impact noise from occurring during gear shifting.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the constituent elements of the present invention;
Fig. 2 is a diagram showing the power transmission mechanism of the continuously variable transmission, Fig. 3 is a diagram showing the combination of operations of each fastening element, and Fig. 4 is a diagram showing the power transmission mechanism of the continuously variable transmission.
Figure 5 shows the control system of the continuously variable transmission, Figure 5 shows the control flow, Figure 6 shows the changing states of each element during gear shifting, and Figure 7 shows the conventional gear shifting. It is a figure which shows the change state of each element. 22...Forward clutch, 24...Overrunning clutch, 30...Forward one-way clutch, 32...Solenoid, 34...
Hydraulic switching valve, 38...Control unit, 4
0...Vehicle speed sensor, 42...Throttle opening sensor, 44...Throttle fully closed switch.

Claims (1)

[Claims] 1. A one-way clutch, a first clutch connected in series with the one-way clutch, and a one-way clutch connected in parallel to the one-way clutch and the first clutch, as fastening elements for switching the connection state of the planetary gear set. There is an upshift transmission that has a second clutch and is performed with the first clutch engaged, and the operating state of the second clutch is controlled by a hydraulic switching valve that is switched according to the on/off state of the solenoid. A shift control device for an automatic transmission to be controlled includes an upshift determination means for determining that an upshift shift is started while a first clutch is engaged, and for detecting that an engine throttle valve is in a fully closed state. When the throttle fully closed detecting means and the upshift determining means determine that the upshift is to be started, and the throttle fully closed detecting means detects that the throttle is fully closed, the solenoid is moved in the direction to engage the second clutch for a predetermined period of time. a solenoid drive means for actuating;
A speed change control device for an automatic transmission, comprising: