JPH0266303A - Hydraulic device - Google Patents

Abstract

PURPOSE:To aim at enhancing the hydraulic efficiency without the necessity of a flow dividing valve by providing an oil passage passing through a second hydraulic system and an oil passage passing through a flow control valve in parallel with each other in an oil passage extending from a hydraulic pressure source to a first hydraulic system. CONSTITUTION:Hydraulic oil from a hydraulic pump 53 flows through a circuit (1) circulating in a second hydraulic system 52 for horizontal control and a circuit (2) which goes through a pilot-operated flow control valve 55, and is then fed into a first hydraulic system for elevation. With this arrangement, the whole amount of hydraulic oil may be fed into the first hydraulic system 51 while a flow rate of hydraulic oil adjusted by the flow control valve 55 may be fed into the second hydraulic system 52, and accordingly, no flow dividing valve is required. Thereby it is possible to reduce loss in pressure in the circuit and to enhance the hydraulic efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention [Field of Industrial Application] The present invention relates to a hydraulic system that can be used, for example, to control a working machine of an agricultural working machine.

[Prior Art] A work machine is attached to a lifting device such as a rear 3P link or a front 3P link, and a single-acting hydraulic cylinder is used to control the work machine's elevation, and a double-acting hydraulic cylinder is used to move the work machine to the left and right. Agricultural working machines that control forward and backward tilting are widely used, and the hydraulic systems of these types of agricultural working machines are divided into two types: a hydraulic system with a single-acting hydraulic cylinder and a hydraulic system with a double-acting hydraulic cylinder. Generally, both are configured to be supplied with pressure oil from a common hydraulic source.

[Problems to be Solved by the Invention] Most of the conventional hydraulic systems described above have a configuration in which pressure oil from a hydraulic source is divided and supplied to both hydraulic systems using a flow divider valve. However, there are problems in that hydraulic efficiency deteriorates due to pressure loss, and appropriate control cannot be performed due to a limit on the 1-minute flow rate.

In addition, even when looking only at hydraulic systems with single-acting hydraulic cylinders, conventional hydraulic systems have two control valves: one for operating the hydraulic cylinder in the direction of raising the work equipment, and the other for operating the hydraulic cylinder in the direction of lowering the work equipment. A lowering control valve for lowering the engine was separately provided, and the hydraulic circuit configuration was complicated. Furthermore, since the internal pressure of the single-acting hydraulic cylinder due to the weight of the lifting device and work equipment was used as the pilot pressure for the lowering control valve, it was difficult to control the lowering speed appropriately when the work equipment was lightweight or at low temperatures. The problem was that there was no.

Structure of the Invention [Means for Solving the Problems] In order to solve the above problems, the present invention has the following structure.

That is, the hydraulic system according to the first invention supplies pressure oil to both the first hydraulic system having a single-acting hydraulic cylinder and the second hydraulic system having a double-acting hydraulic cylinder using a common hydraulic source. The hydraulic system is characterized in that an oil path passing through a second hydraulic system and an oil path passing through a flow rate control valve are provided in parallel with each other in an oil path leading from a hydraulic source to a first hydraulic system. .

Moreover, the hydraulic system according to the second invention is a hydraulic system having a single-acting hydraulic cylinder.

a pilot-operated directional control valve that switches the feeding direction of pressure oil; a first operating valve that operates the directional control valve; It is characterized by comprising a pilot-operated check valve that can prevent the flow of oil to the control valve, and a second operating valve that operates the check valve.

[Function] In the first invention, in the oil passage leading from the hydraulic source to the first hydraulic system, an oil passage passing through the second hydraulic system and an oil passage passing through the flow rate control valve are provided in parallel with each other. By doing so, the first
The circulation part allows the entire amount of pressure oil to flow through the second hydraulic system, and the amount of oil regulated by the flow rate control valve can flow through the second hydraulic system, so a diversion valve is no longer necessary. Therefore, it is possible to eliminate pressure loss due to the flow dividing valve, and also to supply an arbitrary amount of oil to both hydraulic systems.

In the second invention, a pilot-operated directional control valve that switches the feeding direction of pressure oil, a first operating valve that operates the directional control valve, and a pilot-operated directional control valve that is provided in an oil path leading from the directional control valve to the hydraulic cylinder. The directional control valve is configured to include a pilot-operated check valve that can block the flow of oil from the hydraulic cylinder to the directional control valve, and a second operating valve that operates the check valve. For example, when using this for lifting and lowering control of agricultural machinery, when the hydraulic power source is in operation, the hydraulic circuit configuration is simple.
The control valve operates the directional control valve to control the lowering of the work equipment, and when the hydraulic power source is stopped, the second operation valve operates the check valve to perform appropriate lowering control of the work equipment. be able to.

[Example] Fig. 1 and Fig. 2 are diagrams showing the usage state of an agricultural machine which is an example of the present invention.
A rear 3P link 4 is provided at the rear of the a (tractor) 2, and a rotary tiller a5 is attached to this as a working machine.

The rotary tiller M&5 has a transmission case 9 disposed at the center of the upper part of the machine body, and a chain case 11 and side plates (not shown) are separately provided at the ends of left and right pipe frames protruding from both sides of the transmission case 9. A plurality of tilling blades 13 are provided around the chain case and the lower end of the side plate. ... is rotatably supported. The upper and rear portions of this tilling shaft 14 are provided with tilling blades 13. It is covered by a rotary cover 15 that covers the rotation range of...

The rotary cover 15 a is attached to the rotary cover 15 so as to be rotatable up and down by a hinge, and is supported in a suspended state by a hanging rod 19 attached to the rear part of the pitch 18 . A plowing depth sensor 20 is provided on the top of the rotary cover to detect the plowing depth of the tiller by measuring the angle of the rear cover 15a. 22 in Figure 0 is a mast for connecting to the tractor 2; 23 is a connecting plate provided on both sides of the mast, and 24 is a jack for adjusting the height of the hitch 18.

The rear 3P link 4 includes a single wooden top link 30 and a pair of left and right lower links 31.31.The top link 30 is connected to the tip of the mast 22 of the tiller 5, and the lower link 31.31 is connected to the connecting plate 23. 23, respectively.

The lower link 31.31 is suspended from a hydraulic lift arm 33.33 of the tractor 2 by lift rods 32, 32' connected to its intermediate portion. A single-acting lifting hydraulic cylinder 35 is provided on the tractor body side, and by vertically rotating the lift arms 33, 33 with the hydraulic cylinder 35, tilling 4I! 5 is raised and lowered. A lift arm angle sensor 36 is provided at the base of the lift arm to detect the angle of the arm. Further, a double-acting hydraulic cylinder 37 for horizontal control is provided at the intermediate portion of one of the lift rods 32', and by expanding and contracting the hydraulic cylinder, the horizontal inclination of the tiller 5 with respect to the tractor 2 is adjusted. . A stroke sensor 38 is attached in parallel to the horizontal control hydraulic cylinder 37 so as to be able to detect the horizontal inclination. In addition, tiller 5
The driving force is transmitted from the PTO shaft 40 of the tractor.

On the other hand, a tilt sensor 42 is provided on the tractor side to detect left and right tilt of the tractor body. Further, the operator's seat is provided with a position lever 43 for raising and lowering the working machine, a tilling depth setting device 44 for setting the tilling depth of the tiller, and the like.

FIG. 3 is a hydraulic circuit diagram showing the hydraulic system of the agricultural machine I, and this hydraulic system N50 has a first hydraulic system 51 for lifting and lowering having a single-acting hydraulic cylinder and a double-acting hydraulic cylinder. A hydraulic pump 53 is provided as a common drive source for both hydraulic systems 51 and 52, which are composed of a second hydraulic system 52 for horizontal control, and the pressure oil sent out from the hydraulic pumps is provided in parallel with each other. A circuit (1) that circulates through the second hydraulic system 51
) and a circuit via the pilot flow control valve 55 (
2) and is supplied to the first hydraulic system 51.

By controlling the flow rate control valve 55 with the proportional pressure control type operation valve 56, the flow rate through the circuit (1) and the circuit (2) is adjusted.

Incidentally, a circuit configuration as shown in FIG. 4 may be used, and the flow rate control valve 59 may be controlled by a poppet type operation valve 58.

In some cases, instead of adjusting the flow rates of both circuits, the circuit may be configured as shown in FIG.
The internal pressure of the double-acting hydraulic cylinder 37 of the second hydraulic system may be adjusted.

The first hydraulic system 51 includes a pilot type lift control valve 70 that continuously switches the lift control hydraulic cylinder 35 between raising and lowering, an operation valve 71 for the lift control valve, and a lift control valve 70.
A pilot type check valve 72 is disposed in the oil path leading from the hydraulic cylinder 35 to the hydraulic cylinder 35. An operating valve 73, an unload valve 74, etc. of the check valve are provided. The second hydraulic system 52 also includes an electromagnetic left/right tilt control valve 75 that controls the horizontal control hydraulic cylinder 37 in three states: extended, contracted, and neutral.
etc. are provided.

FIG. 6 is a diagram showing the configuration of the control device of this agricultural machine l,
The control device 80 includes a position lever 43° and a plowing depth setting device 4.
4 setting signals, and detection signals from the plowing depth sensor 20, lift arm angle sensor 36, stroke sensor 38, inclination sensor 42, etc. are input to the CPU 82 via the A/D converter 81, and are arithmetic-processed to perform the lifting/lowering operation. Output signals are output to the operating valve 71 for the control valve 70, the operating valve 73 for the check valve 72, the left/right tilt control valve 75, and the operating valve 56 for the flow rate control valve 55.

In the case of rising, the current value of the operating valve 71 is increased to increase the P of the operating valve.
, When boat A is connected, pilot pressure is applied to the lift control valve 70, and the lift control valve 70 is switched to the raised position. Then, the pressure in the circuit is increased by the unload valve 74, and when the pressure exceeds the internal pressure of the hydraulic cylinder 35, oil is sent into the cylinder. When the hydraulic cylinder 35 is extended,
The lift arm 33 rotates upward and the work machine 5 rises.

In the case of descent, the operating valve 73 is opened to enable the check valve 72 to allow reverse flow, and the operating valve 71 is controlled by the elevation control valve 70. That is, when performing a sudden descent, it is sufficient to keep the current value of the operation valve 71 at a low level and leave the elevation control valve 70 in the lowered position, and when controlling the descent speed, the operation valve 71 is energized as appropriate. The A-boat pressure of the lift control valve 70 can be maintained at an appropriate level by doing so.

Further, when lowering the hydraulic pump 53 while the operation is stopped, the lift control valve 70 is fixed at the lowered position because no pilot pressure is generated. Therefore, when the hydraulic pump 53 is stopped, the descending speed is controlled by appropriately opening and closing the operating valve 73. Note that the opening and closing of the operating valve 73 may be controlled by pulse energization.

C. Effects of the Invention As is clear from the above explanation, the hydraulic system according to the present invention does not require a diversion valve even when pressure oil is supplied from a common hydraulic source to two hydraulic systems, Low pressure loss and good hydraulic efficiency.

Further, by configuring the hydraulic system having a single-acting hydraulic cylinder according to the second invention, the number of directional control valves can be reduced to one, and the circuit configuration can be simplified. Furthermore, since the internal pressure of the hydraulic cylinder is not used as pilot pressure, control is no longer affected by the level of the internal pressure.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the use of an agricultural machine as an example of the present invention, Fig. 2 is a rear view thereof, Fig. 3 is a circuit diagram of a hydraulic system, and Figs. 4 and 5 show different implementations. An example hydraulic circuit diagram, FIG. 6, is a block diagram of the control device. l... Agricultural machine, 2... Tractor, 4... Rear 3
P link, 5... Rotary tiller (work machine), 50.
... Hydraulic system, 51... First hydraulic system, 52... Second hydraulic system, 53... Hydraulic pump (hydraulic source), 55...
...Flow control valve, 56, 71.73...Operation valve, 70
...Elevation control valve, 72...Check valve, 75...
Left/right tilt control valve, 80...control device. 3rd area 114 drawing w5

Claims (2)

[Claims] (1) The first one has a single-acting hydraulic cylinder with a common hydraulic power source.
A hydraulic system that supplies pressure oil to both a hydraulic system and a second hydraulic system having a double-acting hydraulic cylinder, wherein the second hydraulic system is provided in an oil path from a hydraulic source to the first hydraulic system. A hydraulic device characterized in that an oil passage passing through the flow control valve and an oil passage passing through a flow control valve are provided in parallel with each other. (2) A hydraulic system having a single-acting hydraulic cylinder, comprising: a pilot-operated directional control valve that switches the feeding direction of pressure oil; a first operating valve that operates the directional control valve; a pilot-operated check valve that is provided in an oil path from the control valve to the hydraulic cylinder and is capable of blocking the flow of oil from the hydraulic cylinder to the directional control valve;
A hydraulic device comprising: a second operation valve that operates the check valve.