JP3480526B2 - Hydraulic control circuit of outrigger device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control circuit for an outrigger device, and more particularly, to a steering circuit or a steering circuit.
The present invention relates to a hydraulic control circuit of an outrigger device for controlling a switching valve for a steering / outrigger device that supplies hydraulic pressure to any of the outrigger devices. 2. Description of the Related Art Conventionally, many wheeled construction vehicles equipped with outriggers do not use the outriggers to support the vehicle body while the vehicle is performing a steering operation. There is no steering operation when supporting. Therefore, as shown in FIG. 2, the hydraulic pump 21 directly connected to the engine 1 via the gear 2 and the gear 2a is commonly used as a hydraulic source for steering operation and for expanding and contracting the outrigger. Hydraulic oil from the hydraulic pump 21 is passed through a steering / outrigger switching valve 22 (hereinafter, referred to as switching valve 22) to a steering circuit 23 and four cylinders 24a of the outrigger, respectively.
24b, 24c and 24d are supplied via an outrigger switching valve 25. The pressure oil from the hydraulic pump 21 passes through the steering circuit 23 when the switching valve 22 is in a neutral position, and the steering is operable. When the outrigger is operated, the switching valve 22 is switched to extend and contract the outrigger. The switching valve 22 is operated using the hydraulic pressure of the hydraulic pump 21. In this case, the switching valve 2
2 is for the operator to select an operation switch (not shown),
The control device 26 such as a controller receives the command and outputs a predetermined command to the selected two-position pilot electromagnetic switching valves 27 and 28 to perform switching. The switching is performed by receiving hydraulic oil from the hydraulic pump 21. As an example of this, a hydraulic circuit of a crane vehicle will be described. When an operation switch (not shown in FIG. 2) is operated to switch the two-position pilot electromagnetic switching valves 27 and 28, the hydraulic pressure of a hydraulic pump 21 directly connected to the engine 1 is switched. 22 is supplied to the outrigger switching valve 25,
Further, each outrigger cylinder 24 is moved by operating the outrigger switching valve 25. However, in the hydraulic circuit shown in FIG. 2, if the electric circuit of the pilot electromagnetic switching valves 27 and 28 fails during operation of the vehicle, or if an operation switch (not shown) is operated erroneously. The outrigger extends and comes into contact with the ground, and no steering oil is supplied to the steering circuit 23 on the downstream side, so that steering becomes impossible, and there is a danger of falling of the vehicle due to extension or collision due to inability of steering. After the pilot solenoid switching valve is switched to retract the outrigger after the stationary work such as a crane operation, the pilot solenoid switching valve is switched to the neutral position if the pilot solenoid switching valve does not return to neutral due to sticking or the like. Since it does not return to neutral, pressure oil is not supplied to the steering circuit, so that traveling becomes impossible and steering becomes impossible. The present invention is directed to a hydraulic control circuit of an outrigger device, focusing on the above-mentioned conventional problems, and in particular, to controlling a switching valve for supplying hydraulic pressure to either a steering circuit or an outrigger device. An object of the present invention is to provide a hydraulic control circuit of an outrigger device for preventing a pilot operation hydraulic switching circuit from erroneously operating a pilot electromagnetic switching valve during steering operation of a vehicle or preventing a steering operation from being disabled due to a malfunction. In order to achieve the above object, according to the present invention, oil from a hydraulic pump driven directly in connection with an engine is supplied to a hydraulic circuit for steering or a hydraulic control for an outrigger device. In a hydraulic control circuit of an outrigger device such as a crane vehicle having a steering / outrigger switching valve which is switched by a pilot hydraulic pressure while switching to a circuit, a pilot operating hydraulic pump driven by an engine via a PTO device, a pilot operating hydraulic pressure Steering the pilot pressure from the pump
And a pilot electromagnetic switching valve for switching and supplying to the outrigger switching valve. According to the above configuration, the connection is released so that the PTO device is not driven while the vehicle is running, and the hydraulic pump for pilot operation does not rotate, so that no hydraulic pressure is generated.
As a result, failure of the electric circuit of the pilot electromagnetic switching valve,
Alternatively, even if the operation switch is erroneously operated, the pressure oil from the pilot operation hydraulic pump is not supplied to the operation portion of the switching valve. For this reason, the switching valve maintains the neutral state without switching,
In order to hold the steering circuit, the outrigger extends and comes into contact with the ground, so that there is no danger of a vehicle falling or a collision due to inability to steer. Further, after the pilot electromagnetic switching valve is switched to retract the outrigger after the stationary operation such as a crane operation and the like, and the pilot electromagnetic switching valve does not return to neutral due to sticking or the like, even if a malfunction occurs, the PTO device is started when the vehicle starts running. The hydraulic pump for pilot operation does not rotate because the connection is disconnected so that the hydraulic pump is not driven, and no hydraulic pressure is generated. As a result, the switching valve is set in a neutral state by the spring of the left and right switching section, and returns to the steering priority circuit, so that there is no danger of collision due to impossibility of running or steering. An embodiment of a hydraulic control circuit of an outrigger device according to the present invention will be described below in detail with reference to the drawings. Note that the same components are denoted by the same reference numerals, and description thereof is omitted. FIG. 1 is an overall configuration diagram of a hydraulic control circuit of the outrigger device. In FIG. 1, the engine 1 includes, on the one hand, a winch hydraulic pump 4, a boom hydraulic pump 5, and a pilot operation hydraulic pump 6 (hereinafter, referred to as a pilot pump 6) via a gear 2, a gear 2b and a PTO device 3. On the other hand, the steering hydraulic pump 7 and the torque control hydraulic pump 8 are directly connected to the gear 2 and the gear 2a. The hydraulic pressure of the pilot pump 6 is guided to the left and right switching units 22a and 22b of the switching valve 22 from the pilot electromagnetic switching valve 9 switched by an operation signal of an operation switch (not shown). In addition, PTO
The device 3 is turned on and off by the operation unit 10 that is switched by a command from the control device 26, and is normally disconnected while the vehicle is running. Therefore, while the vehicle is running, the engine 1
The connection with the pilot pump 6 is released by the PTO device 3, and the pilot pump 6 does not rotate. A hydraulic pressure is always supplied to the switching valve 22 from a hydraulic pump 21 that is commonly used for steering and an outrigger driven through the engine 1. The switching valve 22 is provided with a spring 22c on both the left and right switching units 22a and 22b. Accordingly, when the hydraulic pressure of the pilot pump 6 is zero, the pilot pump 6 is at the neutral position (1). The steering circuit 23 is connected to the neutral position (1) of the switching valve 22. The operation port 22d of the switching valve 22 includes an outrigger switching valve 2
The outrigger switching valve 25 is connected to each outrigger cylinder 24. At any operation position (2) at both ends of the operated neutral position (1), the pressurized oil flows to each outrigger cylinder 24 via the outrigger switching valve 25. The operation will be described with reference to FIG. First, a description will be given of a state in which the vehicle is traveling. When the operator selects traveling by an operation switch (not shown), the engine 1 and the pilot pump 6
And the connection of the PTO device 3 is released. PT
Since the O device 3 is released, the pilot pump 6 does not rotate and no hydraulic pressure is generated. Therefore, the switching valve 22 is not supplied with the hydraulic pressure to the left and right switching units 22a and 22b, and the switching valve 22 is maintained at the neutral position (1) by the spring 22c and is connected to the steering circuit 23. Even if the operation switch (not shown) is erroneously operated and the pilot electromagnetic switching valve 9 is switched, the pilot pump 6 does not rotate, so that no hydraulic pressure is generated and the switching valve 22 is maintained at the neutral position (1). The steering circuit 23 is provided. Next, when a stationary operation such as a crane operation is performed, when the operator selects an operation with an operation switch (not shown), the control device 26 outputs a command to the operation unit 10 and
The connection of the PTO device 3 is performed. When the PTO device 3 is connected, the engine 1 and the pilot pump 6 are connected, so that the pilot pump 6 rotates and generates hydraulic pressure. When an operation switch (not shown) is operated in this state, pressure oil flows to either the left or right switching portion 22a, 22b of the switching valve 22, and the switching valve 22 switches against the spring 22c. As a result, the steering circuit 23 is shut off, and the pressure oil flows to each outrigger cylinder 24 via the outrigger switching valve 25. Even if a malfunction occurs in which the pilot electromagnetic switching valve 9 does not return to neutral due to sticking or the like,
When running the vehicle after the stationary work, the PTO device 3
As a result, the connection between the engine 1 and the pilot pump 6 is disconnected, so that no hydraulic pressure is generated. As a result, the switching valve 22 returns to the neutral position (1) by the spring 22c.
It becomes the steering circuit 23 and safety is maintained. In the above-described embodiment, the hydraulic source of the pilot hydraulic pressure for switching the switching valve 22 is supplied from the pilot pump 6. However, the hydraulic source of the pilot hydraulic pressure is supplied to the winch hydraulic pump driven by the engine via the PTO device. 4 or a boom hydraulic pump 5 or the like. As described above, the present invention drives the pilot pump, which is a hydraulic power source of the pilot electromagnetic switching valve for operating the switching valve, through the PTO device so that the steering is always performed when the vehicle is running. Since the priority is given, there is no danger of the vehicle overturning due to an overhang of the outrigger due to an erroneous operation, or running impossible or steering impossible due to an erroneous operation, and safety is remarkably improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a hydraulic control circuit of an outrigger device of the present invention. FIG. 2 shows a hydraulic control circuit of an outrigger device according to a conventional embodiment. [Description of Signs] 1 ... Engine 3 ... PTO device 6 ... Hydraulic pump for pilot operation 7 ... Hydraulic pump for steering 9 ... Solenoid switching valve for pilot 22 ... Steering / outrigger switching valve 23 ... Steering circuit 24 ... Outrigger cylinder 25 ... Outrigger Switching valve 26 ... Control devices 27, 28 ... 2-position pilot solenoid switching valve.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B66C 19/00-23/94 B60S 3/00-13/02 F15B 11/00-11/22 B62D 5/00-5 / 32 E02F 9/00-9/18 E02F 9/24-9/28

Claims (1)

(57) [Claims] [Claim 1] Oil from a hydraulic pump driven directly connected to an engine is switched to a hydraulic circuit for steering or a hydraulic control circuit for outrigger devices, and is switched by pilot hydraulic pressure. In a hydraulic control circuit of an outrigger device such as a crane vehicle having a steering-outrigger switching valve, a pilot operation hydraulic pump driven by an engine via a PTO device and a pilot pressure from the pilot operation hydraulic pump are used for steering and control. A hydraulic control circuit for an outrigger device, comprising: a pilot electromagnetic switching valve that switches and supplies the outrigger switching valve.