JPH0122506B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission, and more particularly, to an automatic transmission, which includes a plurality of gear connection mechanisms and a plurality of clutches corresponding to the respective connection mechanisms, and automatically changes the rotational speed ratio between an input shaft and an output shaft. Concerning protection devices for automatic transmissions.

An example of this type of transmission is the one shown in FIG. To explain with reference to Figure 1, 1
is the input shaft and 2 is the output shaft. An output shaft of an engine is connected to the left side of the input shaft 1, and a propeller shaft is connected to the left side of the output shaft 2. 3 and 4
is clutch. Clutches 3 and 4 are of the electrically controlled type by means of solenoids. One end of the clutch 3 is connected to the input shaft 1, and the other end is connected to the gears 5 and 6. One end of the clutch 4 is connected to the input shaft 1, and the other end is connected to the gears 7 and 8. Gears 5, 6, 7
and 8 mesh with gears 9, 10, 11 and 12, respectively.

Gears 5-9, 6-10, 7-11 and 8-1
Each set of 2 is a gear connected in the first speed, third speed, second speed, and fourth speed, respectively. Clutch 3 and gears 5 and 6 are integrated, and when clutch 3 is engaged, gears 5 and 6 rotate. Further, the clutch 4 and gears 7 and 8 are integrated, and when the clutch 4 is engaged, the gears 7 and 8 rotate. Gears 9, 10, 11 and 12 are rotatable with respect to output shaft 2. Between the gears 9 and 10 and the gears 11 and 12, there are switching connection mechanisms 13 and 1 fixed to the output shaft 2, respectively.
It is equipped with 4. Therefore, when setting the first speed, the switching connection mechanism 13 is connected to the gear 9, and the third speed is set to the third speed.
For faster speed, connect 13 to gear 10. Further, when setting the second speed, the switching connection mechanism 14 is connected to the gear 11, and when setting the fourth speed, the switching connection mechanism 14 is connected to the gear 12.

In the actual driving state of the vehicle, for example, the first
At high speed, the switching connection mechanism 13 is connected to the gearwheel 9 and the clutch 3 is connected to the input shaft 1. When switching from this state to the second speed, first the switching connection mechanism 14
is connected to the gear 11, and then the clutch 4 is connected while gradually releasing the clutch 3. When changing from the second speed to the third speed, in the same manner, after connecting the switching connection mechanism 13 to the gear 10, the clutch 3 is connected while gradually releasing the clutch 4.

However, in this type of transmission, the input shaft 1
Since there are two paths connecting the output shaft 2 and the output shaft 2, if the timing of connecting the clutches 3 and 4 is incorrect and the two clutches are fully connected at the same time, the output shaft 2 will have different parts. Since the rotational speed force is applied, the output shaft 2 may break or the gear may be damaged. For example, if the gear switching mechanism fails or if the microcomputer malfunctions, two clutches may become engaged at the same time.

The first object of the present invention is to prevent damage to shafts, gears, etc. due to control errors even in the worst case, and the second object is to provide an inexpensive automatic transmission.

In order to achieve the above object, in the present invention, the gear connection state of each part is detected, and if two or more sets of gears are connected to the same output shaft at the same time for a predetermined period or more, the clutch is automatically disconnects to protect the transmission. According to this,
For example, the transmission can be reliably protected with a relatively simple configuration such as cutting off the power to a solenoid that controls the clutch using a relay or the like.

Hereinafter, one embodiment will be described with reference to the drawings. FIG. 2a shows a schematic block diagram of an automatic transmission according to an embodiment, and FIG. 2b shows a schematic diagram of a transmission mechanism. First, explanation will be given with reference to FIG. 2b. In this embodiment, the transmission includes gears for first speed, second speed, third speed, fourth speed, and reverse. In summary,
1st speed gears 5, 9, 3rd speed gears 6, 10, reverse gears 15, 16, 17, 1st clutch 3
etc. constitute one set of transmission mechanism (gearbox), second gear gears 7, 11, fourth gears 8, 1
2. The second clutch 4 and the like constitute another set of transmission mechanisms. The output shaft 2 and the gear 17 are connected by a switching connection mechanism 18.

This will be explained with reference to FIG. 2a. The automatic transmission of the embodiment is centrally controlled by a control computer unit CPU. The digital input port of the computer unit CPU includes a switch that detects the operation of the first clutch 3, a switch that detects the operation of the second clutch 4, and each of the 1st speed, 2nd speed, 3rd speed, 4th speed, and reverse. A switch that detects the connection state of the gears, and a manual range switch are connected. A first clutch stroke signal, oil temperature signal, vehicle speed signal, engine speed signal, and throttle opening signal are applied to the analog signal input port of the computer CPU. The analog signal is converted into a digital signal by an A/D converter inside the computer CPU.

From the output port of the computer unit CPU, five solenoid energizing signals are sent to selectively connect the first gear, second gear, third gear, fourth gear, and reverse gear, and the pressure regulation control is applied to the first clutch 3. An analog control signal for controlling the second clutch 4, an analog control signal for controlling the pressure regulation of the second clutch 4, and a solenoid energizing signal for controlling the second clutch 4 on and off are output. The switching connections 13, 14 and 18, the first clutch 3 and the second clutch 4 are hydraulically controlled in this embodiment. The switching connection mechanism 13 is operated by the biasing of solenoids SL1, SL2, SL3, and the switching connection mechanism 14 is operated by the biasing of solenoids SL4, SL3.
The first clutch 3 is activated by energizing SL5, and the first clutch 3 is energized by SL6.
The second clutch 4 is operated by the biasing of SL7 and SL8.

FIG. 3 shows a schematic operation of the automatic transmission shown in FIG. 2a. This will be explained with reference to FIG.

First, when starting the vehicle, the switching connection mechanism 13 is connected to the first speed gear 9, and the first clutch 3 is loosely connected. When there is a shift command from the first speed to the second speed, the switching connection mechanism 14 is connected to the second speed gear 11. Then, the second clutch 4 starts to be connected and the first clutch 3 starts to be disengaged. 1st
Once the clutch 3 is released, the switching connection mechanism 13 is released from the first speed gear 9. The same operation as described above is performed when there is an instruction to change from second speed to third speed, and when there is an instruction to change from third speed to fourth speed.

When a shift instruction is given from 2nd gear to 1st gear, the 1st gear
The switching connection mechanism 13 is connected to the speed gear 9. Then, the first clutch 3 starts to be connected and the second clutch 4 starts to be disengaged. When the second clutch 4 is released, the switching connection mechanism 14 is disconnected from the second speed gear 11. The same applies to the case of shifting from third speed to second speed and the case of shifting from fourth speed to third speed.

When moving from the first speed state to a stop, the first clutch 3 and the second clutch 4 are both disengaged and the switching connection mechanisms 13 and 14 are set to neutral. Then check whether there is a reverse setting instruction. When a reverse setting instruction is given, the switching connection mechanism 18 is connected to the reverse gear 17, and the connection of the first clutch 3 is started. When the reverse setting is released, the first clutch 3 starts to be disengaged, and when it is released, the switching connection mechanism 18 is connected to the reverse gear 1.
Separate from 7.

FIG. 4 shows the protection circuit 30 included in the control computer unit CPS of FIG. 2a. This will be explained with reference to FIG. SE1, SE2, SE3, SE4
and SE5 are solenoids SL1, SL2, SL3, which drive the switching connection mechanisms 13, 14, and 18;
This is a driver for SL4 and SL5. Driver SE
The output terminals of block B1, SE2 and SE3 are connected to the input terminal of block B1, and the output terminals of SE4 and SE5 are connected to the input terminal of block B1.
The output of block B2 is connected to the input of block B2. Blocks B1 and B2 are NOR circuits. The outputs of block B1 and B2 are connected to the input of block B3. Block B3 is an AND circuit. The output of block B3 is connected to block B4. Block B4 is a timer circuit, consisting of a time constant circuit consisting of a resistor and a capacitor, and an analog comparator. VR1 is a variable resistor that sets the time constant. In this embodiment, the timer time can be changed within the range of 0.5 to 1.5 seconds by adjusting VR1. Inverters IN1 and IN2 are connected to the output end of block B4. The output terminal of the inverter IN1 is connected to the reset input terminal of the microcomputer. In this embodiment, the microcomputer is reset at a low level L. The output terminal of inverter IN2 is connected to transistor Q1 that drives relay RL. Relay RL has two systems of normally closed contacts. These contacts are inserted into the power lines of the solenoid SL6 of the first clutch 3 and the solenoid SL7 of the second clutch 4, respectively. DV1 and DV2 are solenoid SL6
and SL7 control circuit, transistor Q
2 and Q3 are their respective drivers. A light emitting diode indicator is connected in parallel to the solenoid of relay RL.

The output terminals of drivers SE1, SE2 and SE3 are all L (i.e. solenoids SL1, SL2 and SL
3 is de-energized), the output terminal of NOR circuit B1 becomes high level H, but drivers SE1, SE2 and
When any one of SE3 becomes H (ie, solenoid energized), the output terminal of B1 becomes a low level L. Further, when the output terminals of drivers SE4 and SE5 are both low, the output terminal of NOR circuit B2 becomes high, but when the output terminal of driver SE4 or SE5 becomes high, the output terminal of B2 becomes low. Therefore, the output end of OR circuit B3 is connected to either of solenoids SL1, SL2 and SL3 and to solenoids SL4 and SL.
It becomes H only when any one of 5 is energized at the same time, and becomes L otherwise. The timer circuit B4 is
When the input terminal is L, the output terminal is set to L, but when the input terminal becomes H, the output terminal is inverted to H after a predetermined time Tm has elapsed. When the output terminal of timer B4 becomes H, inverter IN2 and transistor Q1
The relay RL is turned on via the relay RL, and the power lines of the solenoids SL6 and SL7 are cut off (ie, the clutch is disconnected).

FIG. 5 shows the approximate operation timing of the clutch and gears when shifting from the first speed to the second speed. This will be explained with reference to FIG. When the switching connection mechanism 13 is connected to the first gear, that is, the gear 9, and the first clutch 3 is in the connected state, when a shift instruction to the second gear is given, the switching connection mechanism 13 is connected to the gear 11 of the second gear.
4, then slowly connect the first clutch 3.
Connect the second clutch 4 while releasing the clutch. If the computer CPU operates normally and the gear shifting operation is successful, the gear shifting operation is completed within a predetermined time Tn after the gear shifting operation is started. However, if the computer CPU goes out of control during gear shifting operation, the first speed gear 9 and the second gear 11 will be connected to the output shaft 2, and the operation will be stopped with the clutches 3 and 4 both connected. . In this case, Tm from the start of gear shifting operation
When this period has elapsed, the protection circuit 30 shown in FIG. 4 is activated, cutting off the power to the solenoids of the clutches 3 and 4 to prevent damage to the output shaft 2. Furthermore, in this embodiment, at the same time, the computer CPU is reset to stop the runaway and return to a predetermined operation.

As described above, according to the present invention, even if the speed change control circuit malfunctions, damage to the output shaft, etc. can be reliably prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an example of the mechanical part of an automatic transmission, FIG. 2a is a device block diagram showing an embodiment of the present invention, and FIG. 2b is a longitudinal cross-sectional view showing the transmission mechanism of the device shown in FIG. 2a. 3 is a flowchart showing the general operation of the control computer unit CPU shown in FIG. 2a, and FIG. 4 is a block diagram showing the protection circuit 30 of the control computer unit CPU shown in FIG. 2a.
FIG. 5 is a timing chart showing an example of a shift operation from the first speed to the second speed of the device shown in FIG. 2a. 1: Input shaft, 2: Output shaft, 3: First clutch (first clutch), 4: Second clutch (second clutch), 5, 6, 7, 8, 9, 10, 11, 1
2, 15, 16, 17: Gear, 13: Switching connection mechanism (first gear connection mechanism), 14: Switching connection mechanism (second gear connection mechanism), 18: Switching connection mechanism, 3
0: Protection circuit (protection control means), B1, B2:
NOR circuit, B3: AND circuit, B4: timer circuit (timer means), CPU: control computer (speed change control means), SE1, SE2, SE3, SE4, SE5:
Solenoid driver (gear connection detection means), RL:
Relay (cutoff means), SL1 to SL7: Solenoid.

Claims (1)

[Claims] 1. A first gear connection mechanism including a first gear mechanism and a third gear mechanism and a gear selection means for selectively connecting these gear mechanisms to an output shaft; a second gear mechanism and a fourth gear mechanism; a second gear connection mechanism comprising gear mechanisms and gear selection means for selectively connecting the gear mechanisms to the output shaft; interposed between the input shaft of the transmission and the first gear connection mechanism; a first clutch interposed between the input shaft and the second gear connection mechanism; a second clutch interposed between the input shaft and the second gear connection mechanism; and the second clutch, first connecting the gear of the specified gear, and then disengaging the clutch corresponding to the previous gear among the first and second clutches and changing the gear to the specified gear. a gear change control means that connects a corresponding clutch and releases the gear connection of the gear position before the gear change after the disengagement of the clutch is completed; the gears of the first gear connection mechanism and the second gear connection mechanism; gear connection detection means for detecting a connection state; and a timer means, which monitors the output of the gear connection detection means, so that the gear of the first gear connection mechanism and the gear of the second gear connection mechanism are simultaneously in the connection state. A protection device for an automatic transmission, comprising: a protection control means that activates a cutoff means to cut off the connection between the input shaft and the output shaft when this state continues for a predetermined time that exceeds the time required for shifting.