JP2595753Y2 - Hydraulic valve device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic valve device, and more particularly to a hydraulic valve device having a directional control valve to which a sensor for detecting a hydraulic pressure supplied to the directional control valve can be attached.

[0002]

2. Description of the Related Art A transmission such as a construction vehicle is provided with a hydraulic clutch device for clutch on / off switching and gear shifting. A control valve is provided to control on / off of the hydraulic clutch device. The control valve includes a direction control valve, a flow control valve, a pressure control valve, and the like. In the direction control valve, a spool for switching an oil passage is movably disposed in a cylinder. Pilot oil pressure is applied to the spool to control its position, thereby controlling the direction of oil flow. ing.

[0003]

In the above-mentioned control valve, for example, a hydraulic pressure sensor is often mounted to detect an abnormality in the clutch hydraulic pressure. In this case, the oil pressure sensor electrically detects an abnormality in oil pressure. In such a control valve, for example, when the spool of the direction control valve is moved, a surge pressure is generated when the spool hits a stopper or the like and the movement ends. This surge pressure appears as a high oil pressure in a very short time. Although an ordinary oil pressure gauge using a Bourdon tube does not detect such a short period of high oil pressure, an oil pressure sensor that electrically detects oil pressure also detects the surge pressure as described above. Such surge pressure usually exceeds the rating of the oil pressure sensor, and the sensor may be damaged.

An object of the present invention is to prevent surge pressure from being transmitted to a hydraulic pressure sensor.

[0005]

SUMMARY OF THE INVENTION A hydraulic valve device according to the present invention includes a direction control valve, a hydraulic pressure detection oil passage, and a throttle. The direction control valve has a movable spool for switching an oil path, and controls a flow direction of oil. The oil pressure detection oil passage is for guiding oil pressure to a sensor for detecting oil pressure supplied to the direction control valve. The throttle portion is provided in a hydraulic pressure detection oil passage,
A hexagon socket set screw is used to suppress the transmission of the surge pressure generated when the direction is changed by the directional control valve to the sensor.
It is formed by forming a through-hole along the axial direction .

[0006]

In the hydraulic valve device according to the present invention, the spool moves when the direction of oil flow is controlled by the direction control valve. When the movement of the spool is completed, a surge pressure is generated. The oil pressure supplied to the directional control valve is guided to the sensor mounting part by an oil pressure detection oil passage,
The oil pressure is detected by, for example, an electric oil pressure sensor attached to the valve device. Here, when the above-described surge pressure is generated, the surge pressure is transmitted to the sensor via the oil pressure detection oil passage, and the oil pressure detection oil passage is provided with a throttle. For this reason, a surge pressure damping effect is obtained by the throttle portion, and transmission of an extremely high oil pressure to the sensor can be suppressed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The control valve shown in FIG. 1 has a directional control valve 2 and an accumulator 3 formed in a valve body 1. The control valve shown in FIG. 1 is schematically shown. Hydraulic oil is supplied to the valve body 1 from an oil supply unit (not shown) via a pipe 5. The supplied hydraulic oil is supplied to the pilot oil passage 6
Is supplied to the directional control valve 2 via the throttle valve 7 and to the accumulator 3 via the throttle 7. The pilot oil passage 6 is provided with an on-off valve 8 for supplying or shutting off the hydraulic oil supplied from the oil supply unit to the direction switching valve 2. The on-off valve 8 is driven to open and close by a solenoid 9. A main oil passage 10 is provided between the throttle 7 and the accumulator 3 and between the directional control valve 2.

The direction control valve 2 has a spool 11 movably provided in the hole 2a and a return spring 12 for returning the spool 11 to an initial position. The spool 11 moves in the hole 2 a by hydraulic pressure supplied via the pilot oil passage 6, and controls the direction of the flow of hydraulic oil from the main oil passage 10. The directional control valve 2 includes:
A first clutch hydraulic pressure supply path 13 for supplying hydraulic oil to a first speed hydraulic clutch device of a transmission (not shown), a second clutch hydraulic pressure supply line 14 for supplying hydraulic pressure to a second speed hydraulic clutch device, Is connected.
The accumulator 3 has a piston 15 movably provided in the hole 3a, and a spring 16 for urging the piston 15 toward an end of the hole 3a.

The directional control valve 2 and the accumulator 3
The on-off valve 8 is connected to a drain oil passage. In the middle of the pilot oil passage 6, an oil pressure detecting oil passage 20 for guiding oil pressure to the sensor mounting portion 1a is provided as shown in an enlarged manner in FIG. Further, a hydraulic pressure sensor 21 for electrically detecting hydraulic pressure is fixed to the sensor mounting portion 1a of the valve body 1. Oil pressure detection oil passage 20
A throttle portion 22 is formed at the entrance of. The diaphragm 22, der those configured to form a transmural <br/> hole 24 along the axial direction on the hexagonal socket set screw 23 is, detachable from the inlet
It is provided as possible. Here, the inside diameter of the oil pressure detection oil passage 20 is about 5.5 mm. In this case, it is desirable that the diameter of the through-hole 24 forming the narrowed portion 22 is 1 mm or less.

Next, the operation will be described. For example, the first
When the speed hydraulic clutch device is turned on, the solenoid 9 is turned on to move the on-off valve 8 to the closed position as shown in FIG. As a result, the pilot oil passage 6 is shut off by the on-off valve 8 and the hydraulic oil from the oil supply unit is
Does not act on And the supplied hydraulic oil is throttle 7
To the accumulator 3 and the main oil passage 10. The flow direction of the hydraulic oil supplied to the main oil passage 10 is supplied to the first clutch hydraulic supply passage 13 by a spool 11 located at a first position as shown in FIG.
The supply path 13 is connected to the first transmission (not shown).
It is connected to the speed hydraulic clutch device. In this state, hydraulic pressure is accumulated in the accumulator 3 and the piston 1
5 has been moved to the position shown in FIG. In this state, the supply oil pressure is also acting on the pilot oil pressure 6, and this oil pressure is guided to the oil pressure sensor 21 via the oil pressure detection oil passage 20. Then, the oil pressure sensor 21 detects the oil pressure.

When shifting from the first speed to the second speed, the solenoid 9 is turned off and the on-off valve 8 is set to the open position as shown in FIG. Thus, the supplied hydraulic oil acts on the end face of the spool 11 via the pilot oil passage 6. Then, the spool 11 moves to the position shown in FIG. 3 against the urging force of the return spring 12. By the movement of the spool 11, the main oil passage 10 and the first clutch hydraulic supply passage 13 are shut off, and the main oil passage 10 communicates with the second clutch hydraulic supply passage 14. As a result, on the transmission side, the first-speed hydraulic clutch device is turned off, and the second-speed hydraulic clutch device is turned on.

At this time, the hydraulic oil accumulated in the accumulator 3 during traveling in the first speed is mainly supplied to the main oil passage 10 under the influence of the throttle 7, and is switched by replenishing the hydraulic oil during gear shifting. Can be performed quickly and smoothly. Here, when the spool 11 moves and its end comes into contact with the end face of the hole 2a (the state shown in FIG. 3), a surge pressure is generated in the supplied hydraulic pressure. This surge pressure results in a very short but very high hydraulic pressure. Here, if the hydraulic pressure sensor 21 detects the surge pressure as it is, it exceeds the rating of the sensor, so that the hydraulic pressure sensor 21 may be damaged. However, in this embodiment, the throttle portion 22 is provided at the inlet of the oil pressure detection oil passage 20. For this reason, the surge pressure is reduced by the damping effect of the throttle section 22, and the high oil pressure is prevented from being directly guided to the oil pressure sensor 21.

FIG. 4 shows a comparison between a conventional example in which the throttle portion 22 is not provided in the oil pressure detecting oil passage 20 and a clutch hydraulic pressure in the present embodiment in which the throttle portion 22 is provided. FIG. 4A shows a normal clutch oil pressure (20 kg / c) because no throttle portion is provided.
It shows a very high oil pressure value compared to m ² ). On the other hand, when the throttle portion 22 is provided as shown in FIG. 3B, the surge pressure is suppressed to about 37 kg / cm ² . Therefore, it is possible to prevent the hydraulic sensor 21 from being damaged.

In the above-described embodiment, the throttling portion 22 is formed by forming the through hole 24 in the set screw 23 with a hexagonal hole. However, the throttling portion 2 is formed by using another orifice or choke.
2 may be configured. The application of the hydraulic valve device of the present invention is not limited to the control valve shown in FIG.

[0015]

As described above, according to the present invention, a throttle portion is provided in the oil pressure detecting oil passage for suppressing transmission of surge pressure to the sensor, and thus the throttle portion is generated when the direction is changed by the directional control valve. Damage to the hydraulic sensor due to surge pressure can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic hydraulic circuit diagram of a control valve employing one embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3 is a hydraulic circuit diagram for explaining the operation of the direction control valve.

FIG. 4 is a hydraulic pressure characteristic diagram for explaining an effect of a throttle provided in a hydraulic pressure detection oil passage in the device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve main body 2 Directional control valve 11 Spool 20 Oil pressure detection oil passage 21 Oil pressure sensor 22 Throttle part

Claims (1)

(57) [Scope of request for utility model registration] A directional control valve for controlling a flow direction of the oil, and a sensor for detecting a hydraulic pressure supplied to the directional control valve. An oil passage for guiding oil pressure, and a set screw with a hexagonal hole provided in the oil passage for oil pressure detection, for suppressing transmission of surge pressure generated at the time of direction switching by the direction control valve to the sensor. Along the axial direction
Hydraulic valve device and a throttle portion that is configured to form a through hole Te.