JPH0121260Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for detecting malfunction of a solenoid valve installed in a pilot operated valve used in an automatic transmission installed in a construction vehicle such as a dump truck or motor scraper. be.

This type of valve has a structure in which the pilot fluid flowing through the spool is cut off by a solenoid valve to allow the spool to slide. If the solenoid valve malfunctions, the spool cannot slide and the valve cannot be switched correctly.

However, it is difficult to confirm whether the solenoid valves are operating correctly, and in multi-speed automatic transmissions equipped with a large number of solenoid valves, it is extremely difficult to detect which solenoid valve is malfunctioning. be.

For this reason, in a multi-speed automatic transmission, there are two
Since one or more solenoid valves are used and each solenoid valve is used in two or more speed stages, if the gear cannot be shifted normally, it is difficult to determine which solenoid valve is malfunctioning. It was difficult to determine, and in the end, we had to disassemble the solenoid valve one by one and investigate.

On the other hand, malfunctions of solenoid valves occur either because foreign matter in the oil bites into the seat of the solenoid valve and the valve remains open due to a failure to form a seal, or when the solenoid valve operation signal is input due to a break in the solenoid, etc. Even if the solenoid valve is opened, the solenoid valve may not open.

The present invention has been developed in view of the above circumstances, and its purpose is to provide a malfunction detection device for a solenoid valve that can easily detect malfunctions of a solenoid valve.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a transmission control hydraulic circuit diagram, which includes cylinders H, M, and L for high, medium, and low speeds, cylinders for 1st, 2nd, and 3rd speeds, and cylinder R for reverse, and valves 1 and 2 for high and low speeds. , 1st, 2nd, and 3rd speed valves 3, 4, and 5, and a reverse valve 6 control the supply of pressure oil to each cylinder, thereby controlling the speed change to each speed stage.

Each of the above-mentioned valves is a pilot-operated valve equipped with a solenoid valve, and each of the solenoid valves 1a, 2a, 3a, 4
By controlling excitation of a, 5a, and 6a as shown in the table of FIG. 2, speed change control is performed to eight forward and forward speeds. In other words, when the solenoid valve 6a and the solenoid valve 2a are excited and switched from the blocking position A to the communicating position B as described later, the reverse valve 6 and the low speed valve 2 become in the communicating position and the reverse cylinder R and the low speed cylinder L extend to become the reverse speed stage, and when each solenoid valve 1a to 6a is demagnetized to the cutoff position A, only the medium speed cylinder M extends through the low speed valve 2 and the high speed valve 1. Therefore, the power is not transmitted and the state is neutral, and when the solenoid valves 2a and 3a are similarly excited to set the communication position B, the low speed valve 2 and the 1st speed valve 3 are switched, and the 1st speed cylinder I and the low speed cylinder L extends and becomes the first forward speed, solenoid valve 2
When a and 4a are energized to set the communication position B, the low-speed valve 2 and the 2nd-speed valve 4 are switched, the 2nd-speed cylinder and the low-speed cylinder L are extended, and 2nd forward speed is achieved, and the solenoid valve 3a is energized. If the communication position B is 1
The high speed valve 3 switches, the first speed cylinder I and the medium speed cylinder M extend, and the third forward speed is achieved.When the solenoid valves 1a and 3a are energized to the communication position B, the first speed valve 3 and the high speed valve are connected. 1 switches to extend the 1st speed cylinder I and the high speed cylinder H, resulting in 4th forward speed, and when the solenoid valve 4a is excited to the communication position B, the 2nd speed valve 4 switches to extend the 2nd speed cylinder and the medium speed cylinder. When the cylinder M extends and becomes the 5th forward speed, and the solenoid valves 1a and 4a are energized to the communication position B, the 2nd speed valve 4 and the high speed valve 1 are switched, and the 2nd speed cylinder and the high speed cylinder H extend. When the solenoid valve 5a is excited and placed in the communication position B, the 3rd speed valve 5 is switched and the 3rd speed cylinder and the medium speed cylinder M are extended, resulting in 7th forward speed, and the solenoid valves 1a, 5a is energized to the communicating position, the third speed valve 5 and the high speed valve 1 are switched, and the third speed cylinder and the high speed cylinder H are extended, resulting in eight forward speeds.

In FIG. 1, 7 is a valve for the direct coupling clutch 8 of the torque converter, and when the solenoid valve 7a is energized to the communicating position B in the automatic position N, the direct coupling clutch valve 9 is placed in the communicating position B. When the direct coupling clutch 8 is turned ON and the solenoid valve 7a is demagnetized to the cutoff position A, the direct coupling clutch valve 9 is set to the drain position C, and the direct coupling clutch 8 is turned on.
OFF, and when the valve 7 for the direct coupling clutch 8 is set to the manual position H, the direct coupling clutch valve 9 is switched to the drain position C only when the solenoid valve 2a is set to the communicating position B and the low speed valve 2 is switched, and the direct coupling clutch 8 is switched to the drain position C. It is set to be turned off.

Each of the valves has a valve body 1 as shown in FIG.
0 is provided with a spool 14 that disconnects the inlet port 11, the outlet port 12, and the drain port 13, and is biased and held by a spring 15 in a position where the outlet port 12 and the drain port 13 are communicated, and the axis of the spool 14 is A hole 18 communicating between the pilot hydraulic chamber 16 and the drain chamber 17 is bored in the hole 18, and the pilot hydraulic chamber 16 is communicated with a pilot pressure source (not shown).
The drain chamber 17 is connected to the tank 20 via the solenoid valve 19.
The hole 18 has a diaphragm 21.
is provided, and the solenoid valve 19 is always held in the cutoff position A, and is switched to the communication position B when the solenoid 19a is energized.

Then, when the solenoid valve 19 is set to the cutoff position A, the hole 1
Since pilot fluid does not flow to spool 1
4 is held at the position shown in the figure, and when the solenoid valve 19 is set to the communication position RO, the pilot fluid flows through the hole 18 and a pressure difference is generated before and after the throttle 21, so that the spool 1
4 slides to the left to communicate the inlet port 11 and the outlet port 12.

As shown in FIG. 4, the electromagnetic valve 19 disconnects the inlet port 22 and the outlet port 23 by pressing the valve body 25 onto the seat 24 and separating them.
The valve body 25 is urged by a spring 26 to a position where it is pressed against the seat 24, and is moved in a direction away from the seat 24 by a solenoid 19a.

For this reason, as shown in FIG. 5, if foreign matter such as dust adheres to the seat 24, the valve body 25 will not be pressed into contact and will remain open at all times, resulting in malfunction.

Therefore, as shown in FIG. 6, a communication hole 30 that opens into the drain chamber 17 of the valve is bored in the electromagnetic valve main body 31, and a hydraulic switch 32 is provided in this communication hole 30.

The hydraulic switch 32 is turned on and off by the piston rod 34 of the cylinder 33 as shown in FIG. 7, and the piston rod 34 is held in the OFF position by the spring 35 and moved to the ON position by the pressure oil in the pressure receiving chamber 36. A pressure receiving chamber 36 opens into the communication hole 30.

Therefore, when the solenoid valve 19 is in the communication position B, the pressure oil in the drain chamber 17 flows between the seat 24 and the valve body 26.
Since they are separated from each other, the water flows out into the tank 20 through the inlet port 22 and outlet port 23.

Therefore, the pressure inside the pressure receiving chamber 36 decreases, and the hydraulic switch 32 is turned off.

Further, when the solenoid valve 19 is in the cutoff position A, the pressure oil in the drain chamber 17 does not flow out to the tank 20, so the pressure in the pressure receiving chamber 36 becomes high and the hydraulic switch 32 is turned on.

From the above, if the solenoid valve of each valve is set to the cutoff position and the transmission is set to the neutral position, each solenoid valve 19
If this is normal, the pressure in the drain chamber 17 will be high, and the pressure in the pressure receiving chamber 36 will also be high and the hydraulic switch 32 will be turned on. Inlet port 2
2 and the outlet port 23 (in other words, in the case of malfunction), the pressure in the drain chamber 17 decreases and the pressure in the pressure receiving chamber 36 also decreases, so the hydraulic switch 32 is turned OFF, and the hydraulic pressure is By displaying a lamp or the like by turning the switch 32 ON/OFF, it is possible to easily detect which solenoid valve is malfunctioning.

In addition, the solenoid (coil) 19 of the solenoid valve 19
Even if the solenoid valve operation signal is input due to a disconnection in a, etc., the hydraulic switch 32 that should be turned off will not switch to the communication position B even if you try to operate it to the communication position B.
Since it is turned on, malfunction of the solenoid valve 19 can be detected.

FIG. 8 is an electric circuit diagram showing malfunction _of each solenoid valve _shown in the transmission control hydraulic circuit _of FIG. _R represents each solenoid valve 7a, 1a, 2a, 5a, 4a, 3a, 6a, OR gate ₄₀₁ to ₄₀₇ , and NAND gate 4.
₁₁ to ₄₁₇ , and hydraulic switches _32D , 3
The output sides of _2H , _32L , 32〓, 32〓, 32〓, _32R are connected to the OR gates 40 ₁ to 40 ₇ and NAND gates 41 ₁ to 41 ₇ , and the outputs of the OR gate 40 and NAND gate 41 are connected to the AND gate 42. ₁ to 4
₂₇ , and the output sides of the AND gates ₄₂₁ to ₄₂₇ are connected to display lamps D', H', L',',',',
It is connected to switching transistors 43 ₁ to 43 ₇ of R'.

44 is a power source for the display lamp.

Therefore, when the solenoid valve is normal and the solenoid valve operation signal R is input, the hydraulic switch 32 is turned off, "1" and "1" are input to the OR gate 40, and the output becomes "1", and the NAND gate 41 Since "1" and "1" are inputted to "1" and the output becomes "0", the output of the AND gate 42 becomes "0", so the switching transistor 43 does not turn on, so the display lamp does not display.

At this time, if the solenoid of the solenoid valve does not operate due to disconnection, etc., the hydraulic switch 32 continues to be ON, so "0" is input to the OR gate 40 and NAND gate 41, the output of the OR gate 40 is "1", and the output of the NAND gate 41. becomes "1", so the output of the AND gate 42 becomes "1", the switching transistor 43 is turned on, the indicator lamp is displayed (lit), and an abnormality in the solenoid valve can be detected.

In addition, if the solenoid valve is normal and the solenoid valve operation signal is not input, the hydraulic switch 32 is ON, so "0" and "0" are input to the OR gate 40, and the output is "0", and the NAND gate Since "0" and "0" are also input to 41 and the output becomes "1", the output of AND gate 42 becomes "0" and the display lamp does not display.

At this time, if a foreign object is caught, the hydraulic switch 32 is turned OFF and "1" is input to the OR gate 40 and NAND gate 41, so the output of the OR gate 40 is "1" and the output of the NAND gate 41 is "1". The output of AND gate 42 is “1”
Therefore, the indicator lamp will appear and an abnormality in the solenoid valve can be detected.

The present invention is as described above, and when trying to excite the solenoid 19a and bring the valve body 25 into the communication position, the solenoid 19a may be disconnected due to a disconnection of the solenoid 19a, etc.
If a is not energized and the valve body 25 is not in the communicating position, the oil pressure at the inlet port 22 will exceed the predetermined pressure and the oil pressure switch 23 will be turned on, causing the indicator lamp to operate. Malfunctions can be detected.

Also, the solenoid 19a is demagnetized and the valve body 25
When attempting to move the switch to the cut-off position using spring force, if the cut-off position is not reached due to foreign matter being bitten, the oil pressure at the inlet port 22 will not exceed the specified pressure and the oil pressure switch 23 will turn OFF, so the indicator lamp will appear. Since it operates, it is possible to detect malfunction of the solenoid valve.

[Brief explanation of the drawing]

Fig. 1 is a transmission control hydraulic circuit diagram, Fig. 2 is a table showing its transmission control, Fig. 3 is a sectional view of a pilot operated valve, Fig. 4 is a sectional view of a solenoid valve, and Fig. 5 is a sectional view of a pilot operated valve.
6 is a sectional view showing an embodiment of the present invention, FIG. 7 is an explanatory view of a hydraulic switch, and FIG.
The figure is a detection electric circuit diagram. 22 is an inlet port, 23 is an outlet port, 30 is a communication hole, and 32 is a hydraulic switch.

Claims (1)

[Scope of utility model registration request] It is provided with a valve body 25 that communicates and shuts off an inlet port 22 connected to a fluid pressure source and an outlet port 23 connected to a tank, and the valve body 25 is placed in a blocking position by a spring force and placed in a communicating position when a solenoid 19a is energized. In a device that detects malfunction of a solenoid valve,
A hydraulic switch 32 is provided which turns ON when the hydraulic pressure of the inlet port 22 exceeds a predetermined pressure, and the excitation signal of the solenoid 19a and the ON of the hydraulic switch 32 are provided.
When the signal is input and when the excitation signal of the solenoid 19a is not input, the hydraulic switch 32 is activated.
A malfunction detection device for a solenoid valve, characterized by being provided with an indicator lamp that operates to indicate when an OFF signal is input.