JPH0781625B2 - Shift control device for automatic transmission - Google Patents

Description

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

(B) Prior Art As an automatic transmission, there is a forward four-speed automatic transmission disclosed in, for example, JP-A-62-62047.

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 is engaged at all forward speeds, that is, first speed, second speed, third speed, and fourth speed. The one-way clutch is the first speed, the second speed and the third speed.
Although it is engaged at the fourth speed, it becomes free at the fourth speed. on the other hand,
The overrunning clutch is not engaged in the D range, and the first speed when engine braking is required,
The second speed and the third speed are engaged. Therefore, at the first speed, the second speed, and the third speed in the D range, the rotational force is always transmitted via the forward clutch and the one-way clutch. With such a configuration, it becomes easy to adjust the timing of the shift between the third speed and the fourth speed.

(C) Problems to be Solved by the Invention However, in the case of the automatic transmission as described above, the first speed, the second speed
Since the torque is always transmitted through the one-way clutch during the shift between the third speed and the third speed, the upshift shift is performed especially in the fully closed state of the throttle, that is, the first speed → the second speed, the first speed. There is a problem that the one-way clutch produces a hitting sound in the case of → 3rd speed and 2nd speed → 3rd speed. That is, in the case of the above gear shift, when the gear shift is started, the engine rotation speed starts 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 rotation speed falls to a state corresponding to the target shift speed, torque is temporarily applied to the one-way clutch, and then the coasting state is set when the shift is completed, so that the one-way clutch becomes free state again. FIG. 7 shows a change state of each element of the shift change. As described above, the torque temporarily acts on the one-way clutch that is in the free state during the shift, so that the one-way clutch is impacted and the impact sound is generated. This hitting sound is unfavorable for driving feeling.

In order to solve such a problem, Japanese Patent Application No. 61-242007 discloses a technique in which a clutch provided in parallel with a one-way clutch is temporarily engaged during shifting. That is, when the upshift is performed in the power off state, the clutch provided in parallel with the one-way clutch is engaged for a predetermined time. However, even in the case of this technique, engine braking does not occur during the first speed, but when the gear shifting is completed in the second speed, an engine braking state occurs as shown in FIG. 8, and then a predetermined time elapses. Since the clutch provided in parallel with the one-way clutch is released to be in the neutral state, the engine brake is temporarily applied immediately after the shift to the second speed, and the driving feeling is not preferable. There is. The present invention aims to solve such problems.

(D) Means for Solving the Problems The present invention provides a clutch provided in parallel with a one-way clutch while the rotation ratio between the input shaft and the output shaft is equal to or less than a predetermined value (that is, immediately before the completion of gear shift). The above problems are solved by fastening them. That is, the present invention relates to the one-way clutch (30), the first clutch (22) connected in series with the one-way clutch, the one-way clutch and the first clutch as the fastening elements for switching the connection state of the planetary gear set. The second clutch (2
4) and, there is an upshift transmission that is performed with the first clutch still engaged, and the operating state of the second clutch is switched depending on whether the solenoid (32) is on or off. This is intended for a shift control device of an automatic transmission controlled by a valve (34), and determines that an upshift shift from a low speed stage to a high speed stage, which is performed with the first clutch engaged, is started. Upshift determination means, power-off detection means (44) for detecting a power-off state, input rotation speed detection means (39) for detecting an input rotation speed of the planetary gear set, and rotation of the output shaft of the planetary gear set. Output rotation speed detecting means (40) for detecting speed, rotation ratio calculating means for calculating a rotation ratio between the input shaft and the output shaft based on signals from the input rotation speed detecting means and the output rotation speed detecting means, When the shift determination means determines that the upshift gear shift is started and the power-off detection means detects the power-off state, the actual rotation ratio calculated by the rotation ratio calculation means is immediately before the gear ratio of the high speed stage. And solenoid driving means for operating the solenoid in the direction of engaging the second clutch until the predetermined value is reached. The reference numerals in parentheses indicate the corresponding parts of the embodiments described later.

(E) Action When the upshift determination means determines that a predetermined upshift is started and the power-off detection means detects the power-off state, the solenoid drive means turns on the solenoid, for example, and the second clutch Is concluded. When the second clutch is engaged, the rotational force is transmitted without passing through the one-way clutch,
In other words, the one-way clutch is in the same state as being engaged, and even if the direction of action of the torque reverses during shifting, the one-way clutch does not change from the free state to the engaged state, and the occurrence of a hitting person is prevented. As the shift progresses, the rotation ratio between the input shaft and the output shaft changes from the low speed state to the high speed state. The second clutch is released when the rotation ratio exceeds a predetermined value, that is, when the rotation ratio is close to the gear ratio of the high speed stage. As a result, engine braking does not occur immediately after the shift to the high speed stage is completed, and the driving feeling becomes good.

(F) Embodiments Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 is a skeleton view of a power transmission mechanism of an automatic transmission with four forward gears and one reverse gear with overdrive. This power transmission mechanism uses an engine output shaft via the torque converter 10.
The input shaft 13 to which the rotational force from 12 is transmitted, the output shaft 14 to transmit the driving force to the final drive device, and the first planetary gear set 1
5, having 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 low one-way clutch 29, and a forward one-way clutch 30. There is. The torque converter 10 has a lockup clutch 11 built-in. First
The planetary gear set 15 includes a sun gear S1 and 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. It is composed of a carrier PC2 that supports the gear P2. The carrier PC1 can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1 can be connected to the input shaft 13 via the reverse clutch 18. Carrier PC1 has forward clutch 22
Also, it can be connected to the internal gear R2 via the forward one-way clutch 30 connected in series thereto, or via the over-running clutch 24 arranged in parallel with the forward clutch 22 and the forward one-way clutch 30. The sun gear S2 is always connected to the input shaft 13, and the internal gear R1 and the carrier PC2 are always connected to the output shaft 14. The low and reverse brake 26 can fix the carrier PC1, and the band brake 28 can fix the sun gear S1. The low one-way clutch 29 is arranged in a direction in which the forward rotation (rotation in the same direction as the engine output shaft 12) of the carrier PC1 is permitted, but the reverse rotation (reverse rotation or forward rotation) is not permitted.

The above-mentioned power transmission mechanism operates the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in various combinations so as to operate each element (S1, S2, R1, R2, PC) of the planetary gear sets 15 and 16.
1, and the rotation state of PC2) can be changed, whereby the rotation speed of the output shaft 14 with respect to the rotation speed of the input shaft 13 can be variously changed. Clutches 18, 20, 22 and 24,
By operating the brakes 26 and 28 in the combination shown in FIG. 3, it is possible to obtain the fourth forward speed and the first reverse speed. In FIG. 3, the circles indicate the operating clutches and brakes, α1 and α2 are the ratio of the number of teeth of the sun gears S1 and S2 to the number of teeth of the internal gears R1 and R2, respectively, and the gear ratio is the output shaft. Input shaft for 14 revolutions
It is the ratio of 13 rotations.

FIG. 4 shows a device for controlling engagement / disengagement of the overrunning clutch 24. The operation of the overrunning clutch 24 is switched by the solenoid 32.
It is controlled by the supply state of the hydraulic pressure. That is, by supplying the oil pressure of the line pressure oil passage 36 to the overrunning clutch 24, it is engaged, and by cutting off the oil pressure supply, the overrunning clutch 24 is released. The solenoid 32 is turned on / off by a signal from a control unit 38 composed of a microcomputer. Signals from an input rotation speed sensor 39, an output rotation speed sensor 40, a throttle opening sensor 42, and a throttle fully closed switch 44 are input to the control unit 38. The input rotation speed sensor 39 detects the rotation speed of the input shaft 13, and the output rotation speed sensor 40 detects the rotation speed of the output shaft 14. It should be noted that clutches other than the overrunning clutch 24, valves such as brakes for controlling hydraulic pressure, and the like are not directly related to the present invention, and therefore description thereof is omitted.

The control unit 38 executes the control shown in FIG. First, the input rotation speed N _T is read from the input rotation speed sensor 39 (step 92), then the output rotation speed N _O is read from the output rotation speed sensor 40 (step 94), and the rotation ratio G, that is, G = N _T / N Calculate _O (96). Next, the throttle opening signal is read from the throttle opening sensor 42 (at 100), and the read throttle opening and output rotation speed are compared with a preset shift pattern to determine an appropriate shift stage in the current driving state. The position is determined (104). Next, it is determined whether the determined shift speed matches the current actual shift speed, that is, whether a shift is necessary (106). When gear shifting is not required, the current operation is maintained in the state (108) and the process returns. If a shift is required, the type of shift is identified (at step 110). That is, which of the 1-2 shift, the 2-3 shift, the 3-4 shift, and the like is identified. Next, a shift command signal is output according to the identified shift type (at step 111). Next, the commanded shift is 1
-2 shift, 1-3 shift or 2-3 shift is determined (at step 112), and otherwise returns, and in the case of the above shift, throttle fully closed switch
It is determined whether 44 is turned on (at 114).
If the throttle fully closed switch 44 is off, the process returns. When the throttle fully closed switch 44 is on, it is determined whether the rotation ratio G calculated in step 96 is less than or equal to a predetermined value g ₁ (step 115). The predetermined value g ₁ is 1-
Predetermined values are set for the two-speed shift, the one-third shift, and the two-third shift, respectively. When the rotation ratio G is larger than the predetermined value g ₁ , the process returns. Also, the rotation ratio G is a predetermined value
If g ₁ or less, the drive signal of the solenoid 32 is output (116 of the same).

After all, by the above control, the 1-2 shift, the 1-3 shift and the 2-shift
When any one of the three shifts is performed, the throttle is fully closed, and the rotation ratio is equal to or less than a predetermined value, the solenoid 32 is turned on and hydraulic pressure is supplied to the overrunning clutch 24. It As a result, the overrunning clutch 24 is engaged. When the overrunning clutch 24 is engaged, the rotational force is transmitted therethrough, and the one-way clutch 30 is in the same state as when engaged. Therefore, even if the transmission direction of the torque changes during the gear shift, the torque is transmitted through the overrunning clutch 24, so that the one-way clutch 30 does not change from the free state to the engaged state, and the impact sound is prevented from being generated. . This overrunning clutch 24
The engagement state of is released when the rotation ratio reaches a predetermined value immediately before the high-speed gear stage. Therefore, the overrunning clutch 24 is released immediately before the shift from the low speed stage to the high speed stage is completed. Therefore, the engine brake does not operate when the shift is completed. Turning on the solenoid 32 during shifting
FIG. 6 shows an off state, a change state of the input rotation speed and the like, a change state of the torque and the like. By engaging the overrunning clutch 24, relative rotation between the inner race and the outer race of the one-way clutch 30 does not occur during shifting, so that a striking sound is not generated even if the torque transmission direction changes. This is clear when compared with the one shown in FIG. 7 above. Further, as described above, the engine braking does not occur at the completion of the shift. This is also clear when compared with the one shown in FIG.

(G) Effects of the Invention As described above, according to the present invention, when the one-way clutch is applied during an upshift shift between gears, when the throttle is fully closed, the rotation ratio is immediately before the high gear. Since the clutch arranged in parallel with the one-way clutch is engaged until the rotation ratio is reached, the striking noise of the one-way clutch at the time of shifting can be prevented and the engine braking can be activated when the shifting is completed. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention, FIG. 2 is a diagram showing a power transmission mechanism of an automatic transmission, FIG. 3 is a diagram showing combinations of operations of respective fastening elements, and FIG. FIG. 5 is a diagram showing a control device for an automatic transmission, FIG. 5 is a diagram showing a control flow, FIG. 6 is a diagram showing a change state of each element at the time of gear shifting, and FIG. 7 is a diagram showing each element at the time of conventional gear shifting. FIG. 8 is a diagram showing a changed state, and FIG. 8 is a diagram showing a changed state of each element during another conventional gear shift. 22 …… forward clutch, 24 …… overrunning clutch, 30 …… forward one-way clutch, 32…
… Solenoid, 34 …… Hydraulic switching valve, 38 …… Control unit, 39 …… Input rotation speed sensor, 40 …… Output rotation 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 second clutch connected in parallel with the one-way clutch and the first clutch as fastening elements for switching the connection state of the planetary gear set. There is a clutch, and there is an upshift that is performed with the first clutch still engaged, and the operating state of the second clutch is controlled by a hydraulic switching valve that is switched depending on whether the solenoid is on or off. In a shift control device for an automatic transmission according to the above, upshift determination means for determining that an upshift shift from a low gear to a high gear, which is performed with the first clutch engaged, is started, and a power-off state is detected. Power-off detection means, input rotation speed detection means for detecting the input rotation speed of the planetary gear set, and rotation speed of the output shaft of the planetary gear set Output rotation speed detection means for detecting the degree of rotation, rotation ratio calculation means for calculating the rotation ratio between the input shaft and the output shaft based on signals from the input rotation speed detection means and the output rotation speed detection means, and upshift determination means. When it is determined that the upshift gear shift is started and the power-off detection means detects the power-off state, the actual rotation ratio calculated by the rotation ratio calculation means is a predetermined value immediately before the gear ratio of the high speed stage. And a solenoid drive means for operating the solenoid in the direction in which the second clutch is engaged until it reaches.