JP2002167811A - Hydraulic circuit of revolving work machine operating machines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts by saving the number of selector valves. SOLUTION: Two control valves are operated by one selector valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for a turning work machine, and more particularly, to a hydraulic circuit for a pilot in which a plurality of control valves of the turning work machine are controlled by a pilot valve operated by a lever. Things.

[0002]

2. Description of the Related Art In a turning machine for civil engineering and construction, such as a backhoe, a backhoe working device having a boom, an arm, a working tool and the like at a front portion of a turning table supported rotatably on a traveling machine table, and a rear section. A pilot that controls the actuators such as a traveling motor, a swing motor, a boom cylinder, an arm cylinder, and a work implement cylinder at the left and right front sides of the swivel table, and operates the control valve. A valve is provided in the operation unit, and a plurality of hydraulic pumps are driven by an engine to supply pressure oil to the control valve and the pilot valve.

[0003] The control valves are arranged on a board of a swivel table by connecting a large number of control valves in series, and some of them are controlled by lever operation of a pair of pilot valves of an operating unit. An unload valve, an offset switching valve, and the like are provided between the hydraulic pump at the rear of the table and the pilot valve at the upper front, and a pilot oil path switching valve, a stop valve, and the like are provided between the pilot valve and the control valve. I have.

[0004]

In the above-mentioned prior art, a turning operation (turning around the vertical axis of the turning table, which is forward / reverse operation) and a swinging operation (turning the backhoe working device in the left-right direction) are performed. The two pilot hydraulic switching valves are installed between the pilot valve and the control valve in order to operate with one operating lever (for example, reciprocal operation). Thus, safety measures were taken by forming a drain circuit to the tank circuit.

However, the pilot hydraulic switching valve is
It is costly to mount them, and when the switching valve is an electromagnetic valve, the cost tends to increase significantly.
An object of the present invention is to enable two control valves to be operated even if one pilot hydraulic pressure switching valve is formed, to be compact in design, and to reduce costs.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a hydraulic circuit for a pilot in which a plurality of control valves of a turning work machine are controlled by a pilot valve operated by a lever. Have taken strategic steps. That is,
The hydraulic circuit of the turning work machine according to claim 1 is characterized in that one switching valve is switched by one pilot valve to control two control valves.

As described above, since there is only one switching valve, cost can be reduced and a compact design can be realized. In the present invention, it is recommended that the switching valve be provided with a drain circuit for releasing the pressure of the control valve on the closing side during the switching (claim 2). With such a configuration, the operation is prevented from continuing even if the switching is performed unexpectedly (unexpectedly). In the present invention,
The two control valves are optional as long as they operate differently, but it is recommended that one is a swing control valve and the other is a swing control valve (claim 3).

This is because the swing operation of the turntable and the swing operation of the backhoe working device are operated in a relationship, and the swing operation includes an offset operation.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows an entire turning work machine 1 exemplified as a backhoe employing a hydraulic circuit according to the present invention, and FIG. 1B shows a control table device 2 thereof. In FIG. 1 (1), the turning work machine 1 includes a left and right crawler type traveling device 3 and a turning machine body 5 that can turn (forward / reverse rotation and 360 ° rotation) around a vertical axis X via a turning bearing 4. Supported.

The left and right crawler type traveling devices 3 are constructed by endlessly suspending a rubber crawler belt 7C around a driving sprocket 7A and an idler 7B provided before and after the track frame 6, and the left and right driving sprockets 7A are hydraulic motors ( The motor can be rotated forward and backward by a traveling motor. The turning body 5 includes
The engine 8 is mounted, and this engine 8
, And includes a cockpit device 2 and a driver's seat 10, which is surrounded by a cabin 11.

A working device 12 is provided at the front of the turning machine 5. The working device 12 includes a swing bracket 13 that is supported on the turning machine 5 so as to be rotatable around a vertical axis. A boom 14 whose base (lower end) is pivotally attached to the bracket 13 so as to be rotatable around a horizontal axis, and an arm 1 which is pivotally attached to the tip of the boom 14 so as to be able to bend and extend.
5 and a bucket 16 provided on the arm 15, each of which can be driven by a boom cylinder 17, an arm cylinder 18, a bucket cylinder 19, etc., and a dozer device 20 between the left and right crawler-type traveling devices. ing.

The control table apparatus 2 is provided with a pilot valve 23 operated by left and right operation levers 22L and 22R on a control tower 21.
The main structure is provided with L, 23R, and can be manually operated from the driver's seat 10. Referring to FIG. 2, the entire configuration of the hydraulic circuit is illustrated, and the hydraulic circuit includes left and right traveling motors 24L and 24R, a swing motor 25, a tozer cylinder 2
6, a control valve device 28 for controlling the swing cylinder 27, the arm cylinder 18, the boom cylinder 17, and the bucket cylinder 19, respectively. The control valve device 28 is built in the turning machine body 5 as shown in FIG.

The control valve device 28 communicates with high-pressure oil passages (including pipes, hoses, etc.) of a plurality of pumps P driven by the engine 8 and is connected to an oil tank 29 via a low-pressure circuit. . The control device 28 includes a straight traveling control valve 28-1, a turning motor control valve 28-2, a dozer control valve 28-3, a swing control valve 28-4, a service port control valve 28-5, and an arm control valve 28-6. Boom control valves 28-7, 28-8, traveling motor control valve 28-
9, 28-10, and a bucket control valve 28-11, and has an electromagnetic switching type, manual or foot-operating switching type spool.

In the control valve device 28, a large number of the control valves described above are connected in series in front, rear, left and right or up and down to form an integrated control valve group. Each control valve in the control valve device 28 connects and disconnects a high-pressure oil passage to one of a pair of hydraulic oil passages by moving a spool in the axial direction, and some of the control valves are operated by pilot hydraulic pressure. The other is operated by a pedal or a lever via an operating means such as a link. The control valve operated by the pilot hydraulic pressure is, for example, a turning control valve 2.
8-2, swing control valve 28-4, arm control valve 28-
6, boom control valves 28-7, 28-8, etc., and pilot oil can be supplied from pilot valves 23L, 23R operated by a pair of left and right operation levers 22L, 22R.

In the present invention, one pilot valve 2
One control valve 30 is switched by 3L to control two control valves, in the embodiment, the turning control valve 28-2 and the swing control valve 2
8-4. FIG. 3 and FIG.
The hydraulic circuit shown in FIG. 2 is partially enlarged and shown on the left and right sides, and broken lines in FIG. 2 to FIG. 4 indicate pilot hydraulic pressures. Hydraulic pressure can be supplied via the supply unit valve 31.

As shown in FIGS. 2 to 5, the switching valve 30 is
The solenoid valve is a position-switchable electromagnetic valve, and a drain circuit is formed at each of two positions. The operation control lever 23L is operated to control the turning control valve 28-2 and the swing control valve 28-.
4, a switching oil can be supplied to the switching valve 30. The switching valve 30 has a drain for releasing the pressure of the control valve on the closing side during the switching (in the embodiment, the turning control valve and the swing control valve). It has a circuit. That is, for example, during the turning operation, when the pilot oil is supplied to the turning control valve 28-2 and turning is performed in either forward or reverse, the swing control valve 28-4 is unexpectedly turned against the driver's intention ( The drain circuit is formed so that the turning is stopped (so that the operation is not continued) even if it is switched to "unexpected".

Although the embodiment of the present invention is as described above, various design changes are possible. For example, a turning work machine
It may be an ultra-small swivel type or a standard type, and may be a type provided with a canopy instead of the cabin or a type not provided with these.

[0018]

As described above in detail, according to the present invention, one pilot valve switches one switching valve to control two control valves, so that the number of switching valves can be reduced and the number of parts can be reduced. Can be designed to be compact and cost can be reduced.

[Brief description of the drawings]

FIG. 1 shows a turning work machine adopting the present invention, (1) is an overall side view thereof, and (2) is an elevational view of a control console device.

FIG. 2 is a hydraulic circuit diagram of the present invention.

FIG. 3 is a left half circuit diagram in which FIG. 2 is divided into right and left parts and partially overlapped.

FIG. 4 is a circuit diagram of the right half of FIG. 2;

FIG. 5 is a circuit diagram showing a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 turning work machine 2 flight control device 22L operating lever 23L pilot valve 25 turning motor 27 swing cylinder 28 control valve 30 switching valve

Continuation of the front page (72) Inventor Taketoshi Sugimoto 64 Ishizukita-cho, Sakai-shi, Osaka F-term in Kubota Sakai Works (reference) 2D003 AA01 AB02 CA02 DA03 3H089 AA60 AA71 BB27 CC01 CC08 DA03 DA13 DB47 DB48 DB49 EE17 GG02 JJ01

Claims (3)

[Claims] In a pilot hydraulic circuit for controlling a plurality of control valves of a turning work machine by a pilot valve operated by a lever, one pilot valve switches one switching valve to control two control valves. A hydraulic circuit for a turning work machine. 2. The hydraulic circuit according to claim 1, wherein the switching valve includes a drain circuit for releasing pressure of the control valve on the closing side during the switching. 3. The hydraulic circuit for a swing working machine according to claim 1, wherein one of the two control valves is a swing control valve, and the other is a swing control valve.