JPH0148167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protection device for increasing safety when switching a shift range changeover switch in a switch type automatic transmission of an automobile to a forward shift range and a reverse shift range.

2. Description of the Related Art Automatic transmissions in which a shift range switching lever installed on the floor is operated are conventionally known. This type of automatic transmission is inconvenient because it requires a large amount of force to operate the shift lever and the operating stroke is long. An automatic transmission that switches the shift lever has been developed. However, with conventional switch-type automatic transmissions, even when the vehicle is moving forward,
You can easily turn on the reverse switch (R-switch), and the gear range selection lever will try to switch to the reverse position, causing the gears to forcefully engage, resulting in damage or the motor seizing up due to the load. There is a risk that the vehicle may become unable to run. Furthermore, since the drive switch (D-switch) can be turned on even when the vehicle is reversing, a similar danger may occur. Conventionally, in Japanese Utility Model Application Publication No. 57-25237, safety has been improved by making it possible to change the gear range only when a manual push-button check switch is pressed in addition to the gear range changeover switch. By increasing the speed of the parking switch (P
- switch) and reverse switch are engaged only when the vehicle is stopped, and a device has been proposed in which the first speed fixed switch (L-switch) is engaged only at 40 km/h or less. However, since this conventional device uses a speedometer, it cannot eliminate the risk of turning on a forward gear range changeover switch such as a drive switch while the vehicle is moving backward. In addition, since this conventional device uses a relay circuit, it is difficult to add design freedom or high-level control functions compared to when using an electronic circuit, and it is difficult to add a speedometer with a special structure. There are disadvantages such as requiring it.

In addition, in the conventional Japanese Utility Model Publication No. 48-32823 and Japanese Utility Model Application Publication No. 57-199132, in vehicles such as forklift trucks, vehicle speed is detected by the frequency of pulses generated by a non-contact speed sensor, Regardless of whether the vehicle is moving forward or backward, when the vehicle speed is above a certain speed, the current to the solenoid is cut off, and the rod or plunger of the solenoid safety lock is biased by a spring to close its tip. A locking device has been disclosed that prevents a shift lever that protrudes into the forward/reverse change passage and is in the forward F or reverse R position from being shifted to reverse R or forward F. If simply adopted in a type automatic transmission, the gear range switching lever would be moved by the drive of a servo motor or other electromagnetic means, whereas the gear range switching lever would be fixed by the rod or plunger. There is a problem in that a large load is applied to the servo motor or other electromagnetic means and there is a risk of damage.

Furthermore, Japanese Patent Application Laid-Open No. 56-57525 discloses a method that uses an engine speed (or throttle opening) signal to prevent N→D or N→R shifting when the engine speed is higher than a set value. A safety device for vehicles with automatic transmissions has been disclosed, but there is not a one-to-one correspondence between vehicle speed and engine speed, and for example, if the vehicle coasts in N gear on a gentle downhill slope, If an attempt is made to change from N to R while the vehicle is in the vehicle, this change will occur because the engine speed is low, which poses a problem in that there is a risk of damage to the automatic transmission.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and the present invention prevents automatic gear shifting from malfunctioning of the shift range switching switch even when the vehicle is moving forward at a speed higher than an arbitrary set vehicle speed or when the vehicle is moving backward. It is an object of the present invention to provide a protection device for a switch type automatic transmission, which can protect the automatic transmission and allow switching between a plurality of forward shift ranges while the vehicle is moving forward.

Therefore, the protection device for a switch type automatic transmission of the present invention includes a vehicle speed sensor that generates a two-phase signal that has a frequency component proportional to the vehicle speed and whose phase relationship is reversed during forward rotation and reverse rotation; Each sensor is provided on the output side of the vehicle speed sensor, calculates the two-phase signal, determines whether the vehicle is moving forward or backward by reversing the phase relationship, and has a frequency component proportional to the vehicle speed. A first arithmetic circuit that generates a signal, and when the first arithmetic circuit determines that the vehicle is moving forward or backward, the vehicle speed is higher than the arbitrarily set vehicle speed based on the frequency component of the signal. a plurality of shift range switching switches that generate H and L signals for selectively converting the reverse gear range and the forward gear range; H selected in
a second arithmetic circuit that inputs the L signal and the H and L signals from the exchange means to determine permission to change the transmission range and generates a command signal; and the command signal of the second arithmetic circuit controls the automatic transmission. and an electromagnetic means drive circuit that controls the drive of the electromagnetic means that switches the gear range, and when the vehicle speed exceeds an arbitrary set speed, switches from the forward gear range to the reverse gear range, and from the reverse gear range. The present invention is characterized in that driving of the electromagnetic means for switching to the forward speed range is prohibited.

According to the above configuration of the present invention, the vehicle speed sensor that generates the two-phase signal, the first arithmetic circuit, and the conversion means indicate whether the vehicle is moving forward or backward, and the vehicle speed is higher than or equal to an arbitrarily set vehicle speed. The H and L signals from the shift range changeover switch are obtained and the H and L signals from the shift range changeover switch are
The arithmetic circuit determines whether the vehicle is moving forward or backward, and the transmission range can be switched depending on whether the vehicle is moving forward or backward, and the automatic transmission can be protected from erroneous operation of the shift range switching switch.

The present invention will be described below with reference to embodiments illustrated in the drawings. In FIG. 1, 1 is a vehicle speed sensor that generates two two-phase signals. This vehicle speed sensor 1 is
It consists of a perforated disk having a large number of equally spaced through holes and two sets of light emitting and receiving sets, with a distance of 90° in electrical angle maintained between the sets of light emitting and receiving sets. The clock pulse output from terminal A of the vehicle speed sensor 1 is output with a 90° phase advance as shown in Figure 2a when moving forward, and a 90° phase delay as shown in Figure 2b when reversing. be done. That is, the vehicle speed sensor 1 is configured to generate a two-phase signal that has a frequency component proportional to the vehicle speed and whose phase relationship is reversed during forward rotation (forward rotation) and reverse rotation (reverse rotation).

2 is a D-type flip-flop. This flip-flop 2 has an input pulse as a two-phase signal, and when the pulse applied to the input terminal D is ahead of the pulse applied to the terminal CL and the vehicle is moving forward, the output terminal Q becomes a high level. (hereinafter referred to as H). Conversely, when the phase of the pulse input to the terminal D from the terminal CL is delayed, such as when the vehicle is moving backward, the output terminal becomes H. Here, opposite outputs are always generated between the terminal Q and the terminal, and when the terminal Q is H, the terminal is at a low level (hereinafter referred to as L), and when the terminal Q is L, the terminal is at an H level.

3-1 and 3-2 are the D-type flip-flops 2.
This is an AND gate that together constitutes the first arithmetic circuit. One of the two input terminals is connected to the output terminal Q of the flip-flop 2, and the other terminal is directly connected to the terminals A and B of the vehicle speed sensor 1, respectively. In the AND gates 3-1 and 3-2, the output side terminal does not go high unless both input side terminals go high.

4-1 and 4-2 are frequency-voltage converters.
Here, the frequency is from the vehicle speed sensor 1 to the flip-flop 2, and then to the AND gate 3.
-1, and the number of pulses within a unit time in the pulse train outputted through the AND gate 3-2.

13-1 and 13-2 are inverter gates that constitute conversion means together with the frequency-voltage converters 4-1 and 4-2; if the input is H, the output is L; and vice versa. Then the output becomes H. If the output voltage of the frequency-voltage converters 4-1, 4-2 is above the threshold level (threshold value) of the inverter gates 13-1, 13-2, it outputs L, but on the contrary, it is below the threshold level. If the voltage is , it outputs H. Utilizing this relationship, by changing the threshold levels of the inverter gates 13-1 and 13-2, the input from the transmission range changeover switches 7 to 10 can be canceled at a safe vehicle speed of, for example, 0 to 10 km/h. The vehicle speed can be set, and the set vehicle speed can also be set separately for a plurality of forward shift ranges and reverse shift ranges.

Inverter gate 13-1 is connected to one terminal of forward AND gates 3-4, 3-5, and 3-6, and inverter gate 13-2 is connected to one terminal of backward AND gate 3-3. ing. The other terminals of the reverse AND gate 3-3 and the forward AND gates 3-4, 3-5, and 3-6 are connected to a reverse switch R, which serves as a shift range changeover switch for reverse, and a forward switch, respectively. The power supply positive terminal (+ ) is connected. Reference numeral 11 denotes a shift range changeover switch as a neutral switch N, and 12 a shift range changeover switch as a parking switch P, whose H and L signals are directly introduced into the motor drive circuit 5.

Backward AND gate 3- forming the second arithmetic circuit
3, and forward and gates 3-4, 3-5,
The output terminal 3-6 is connected to a motor drive circuit 5 forming an electromagnetic means drive circuit. The motor drive circuit 5 is a manual valve (not shown) of an automatic transmission.
Controls the drive of a servo motor (electromagnetic means) 6 that operates the servo motor (electromagnetic means).

Next, the operation will be explained. One of the plurality of forward gear ranges is selected by a gear range switching switch 8, 9,
10, etc., and the vehicle is moving forward, the pulse as a two-phase signal output from the vehicle speed sensor 1 is such that terminal A is higher than terminal B.
The phase is advanced by 90°. Therefore, on the output side of the D-type flip-flop 2, the terminal Q becomes H and the terminal becomes L. When the vehicle speed sensor 1 generates an output, the output side of the AND gate 3-1 also becomes H when the signals at both input terminals become H. Then, a pulse train having a waveform similar to that of pulse D in FIG. 2a is input to the frequency-voltage converter 4-1, and a voltage corresponding to the frequency (vehicle speed) is generated. Then, the voltage is the inverter gate 13-2
If the vehicle speed is higher than the threshold level, that is, if the vehicle speed is higher than the arbitrarily set vehicle speed, the output side of this inverter gate 13-2 becomes L, and this signal L becomes one of the input terminals of the reverse AND gate 3-3. Therefore, even if the reverse switch R, which is the reverse gear range changeover switch 7, is turned on, the output of the reverse AND gate 3-3 becomes L, and there is no output from the motor drive circuit 5, and the servo motor 6 is not actuated to the retracted position. That is, when the vehicle is moving forward and the vehicle speed is higher than the arbitrarily set vehicle speed, the switching operation of the motor drive circuit 5 from the plurality of forward gear ranges to the reverse gear range is performed by the reverse AND gate 3-3. prohibited.

On the other hand, even during forward movement, the output terminal of the D-type flip-flop 2 outputs L as described above, so the output voltage of the AND gate 3-2 is always L, and the frequency-voltage converter 4 -2 output voltage is zero. Therefore, since it is below the threshold level of inverter gate 13-1,
Naturally, the output of this inverter gate 13-1 becomes H, and the forward AND gates 3-4, 3-5, 3-
Since the signal at one terminal of 6 is H, when any of the multiple forward speed change range changeover switches 8, 9, and 10 is turned on, the signals from these speed change range changeover switches 8, 9, and 10 are turned on. When the H signal is applied to the motor drive circuit 5 via any of the forward AND gates 3-4, 3-5, and 3-6, the servo motor 6 performs a switching operation between these forward speed ranges. . In other words, when the vehicle is moving forward, even if the vehicle speed is higher than the arbitrarily set vehicle speed, switching between multiple forward shift ranges is permitted by the forward AND gates 3-4, 3-5, and 3-6. .

When the vehicle is moving backward, the pulse at the output terminal A of the vehicle speed sensor 1 is delayed in phase by 90 degrees from the clock pulse at the terminal B, as shown in FIG. 2B. D
The output of the type flip-flop 2 is that the terminal Q is L and the terminal is H, which is the complete opposite of the state when moving forward, and the output of the inverter gate 13-1 is L, so that when the vehicle speed exceeds the set vehicle speed described above. In some cases, no H signal is input to the motor drive circuit 5 and the servo motor 6 does not operate even if any of the forward speed range changeover switches 8, 9, and 10 is turned on. In other words, when the vehicle is reversing and the vehicle speed is higher than the arbitrarily set vehicle speed, the switching operation of the motor drive circuit 5 from the reverse gear range to the forward gear range is performed by the forward AND gates 3-4, 3-.
5, 3-6.

When the vehicle is stopped, there is no pulse output from the vehicle speed sensor 1, so even if one of the output terminals Q of the D-type flip-flop 2 is H and the other is L, the frequency-voltage converter 4-1 ,4-
The output from 2 becomes L (zero). Since the output of both inverter gates 13-1 and 13-2 is H, any one of the multiple forward and reverse shift range changeover switches 7, 8, 9, and 10 can be used to select the desired shift position. The H signal is passed through the backward AND gate 3-3 and the forward AND gate 3-.
4, 3-5, 3-6 to the motor drive circuit 5. Further, once any one of the speed change range changeover switches 7, 8, 9, and 10 is operated, the motor drive circuit 5 is automatically activated and the servo motor 6 is activated if the conditions for drive control are met.

As another embodiment, even if the shift range changeover switch 12 serving as the parking switch P is turned on while the vehicle is moving forward, the motor drive circuit 5
In order to prevent the servo motor 6 from operating, an AND gate 3 is connected in series with the speed range changeover switch 12, as shown by the two-dot chain line in FIG.
It is also possible to connect -7 and introduce the L output of the inverter gate 13-2 to the other terminal of the AND gate 3-7. Furthermore, it is also possible to use a two-phase AC output generator and a pulse shaping circuit as the vehicle speed sensor 1 that generates two-phase output.

Motor drive circuit 5 as an electromagnetic means drive circuit
In addition to the usual servo motor drive circuit equipped with a variable resistor for storing command position, a differential amplifier, and a feedback potentiometer, various drive circuits can be used. Although a servo motor was used as the electromagnetic means to be driven and controlled by the electromagnetic means drive circuit, an electromagnet (solenoid) may also be used.

As described above, the switch type automatic transmission protection device of the present invention uses a vehicle speed sensor that generates a two-phase signal that has a frequency component proportional to the vehicle speed and whose phase relationship is reversed during forward rotation and reverse rotation. , is provided on the output side of the vehicle speed sensor, calculates the two-phase signal, determines whether the vehicle is moving forward or backward by reversing the phase relationship, and has a frequency component proportional to the vehicle speed. A first arithmetic circuit that generates each signal, and arbitrary settings based on the frequency components of the signals when the respective signals are generated when the vehicle is moving forward or backward, as determined by the first arithmetic circuit. Exchange means for respectively generating H and L signals for determining whether the vehicle speed is above or below the vehicle speed;
A plurality of shift range switching switches that generate H and L signals for selectively converting the reverse gear range and the forward gear range, and the H and L signals selected by the changeover switches and the H and L signals from the exchange means. a second arithmetic circuit that inputs a signal to determine permission for shifting the gear range and generates a command signal; and drive control of an electromagnetic means for operating the automatic transmission to switch the gear range based on the command signal of the second arithmetic circuit. and an electromagnetic means drive circuit for switching from the forward gear range to the reverse gear range and from the reverse gear range to the forward gear range when the vehicle is at a speed higher than an arbitrary set speed. Therefore, even if the shift range changeover switch malfunctions when the vehicle is moving forward or backward at a speed higher than the arbitrarily set vehicle speed, the second arithmetic circuit prohibits automatic operation. This has the excellent effect that the electromagnetic means for switching the transmission range does not operate, thereby protecting the automatic transmission. In addition, there is no need for a speedometer with a special structure, and since it uses an electronic circuit, it is easy to add advanced control functions, and there are fewer restrictions when installing it. It has many excellent effects, such as being able to freely switch between a plurality of forward shift ranges when the vehicle is moving forward at a set vehicle speed or higher.

Furthermore, the present invention does not control the shift range switching operation of an automatic transmission based on the engine speed, but rather controls the shift range switching operation based on the vehicle speed. It is possible to prevent switching from N to R during
Extremely safe.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the device of the present invention, and FIG. 2 is a waveform diagram showing output pulses of a vehicle speed sensor. 1... Vehicle speed sensor, 2... D-type flip-flop, 3-1, 3-2... AND gate, 3-3...
…Backward and gate, 3-4, 3-5, 3-6
...Forward AND gate, 3-7...And gate, 4-1, 4-2...Frequency/voltage converter, 5
... Motor drive circuit, 6 ... Servo motor, 7 -
12...Reverse switch R, drive switch D, first speed fixed switch L, second speed fixed switch 2, neutral switch N, parking switch P, 13-1,
13-2...Inverter gate.

Claims (1)

[Scope of Claims] 1. A switch-type automatic transmission comprising a shift range changeover switch, an automatic transmission, and electromagnetic means for switching the automatic transmission between a forward shift range and a reverse shift range. , a vehicle speed sensor that generates a two-phase signal that has a frequency component proportional to the vehicle speed and whose phase relationship is reversed during forward rotation and reverse rotation; and a vehicle speed sensor that is provided on the output side of the vehicle speed sensor and that calculates the two-phase signal. a first arithmetic circuit that determines whether the vehicle is moving forward or backward by reversing the phase relationship and generates respective signals having frequency components proportional to the vehicle speed; An exchange that generates H and L signals, respectively, which determine whether the vehicle speed is above or below an arbitrarily set speed based on the frequency component of the signal when a signal is generated indicating that the vehicle is moving forward or backward, as determined by the arithmetic circuit. means, a plurality of shift range switching switches that generate H and L signals for selectively converting between the reverse gear range and the forward gear range; a second arithmetic circuit that inputs H and L signals to determine permission for shifting the gear range and generates a command signal; and an electromagnetic means for operating the automatic transmission to change the gear range based on the command signal of the second arithmetic circuit. and an electromagnetic means drive circuit for controlling the drive of the vehicle, and when the vehicle speed is higher than an arbitrary set speed, switching from the forward gear range to the reverse gear range, and from the reverse gear range to the forward gear range. A protection device for a switch-type automatic transmission, characterized in that it prohibits the electromagnetic means from being driven.