JPH035205Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid pressure circuit for an agricultural tractor in which a double-acting cylinder control valve is permanently installed for a cylinder that is separably connected to a pressure fluid outlet.

Conventionally, in the agricultural tractor mentioned above, when attempting to operate the single-acting cylinder by connecting it to the fluid outlet, when the cylinder is operated to discharge fluid, the fluid supplied from the pump is diverted through the safety relief channel. The fluid has to be returned to the tank, and if the fluid is returned frequently, the fluid temperature will rise abnormally, so in reality, it is not possible to connect a single-acting cylinder, and the work requires connecting the attachments of the single-acting cylinder. Because it cannot be used, its versatility has decreased.

The purpose of this invention is to make it possible to operate even a single-acting cylinder without using a safety relief flow path, and to make it advantageous in terms of adjustment effort, economy, and safety. It is in.

The present invention provides a fluid pressure circuit for an agricultural tractor as described above, in which a single acting cylinder is removably connected to the control valve side, and a pair of cylinders on the control valve side are connected to the control valve side. A first and second control valve side port that can be separately connected to and separated from the side port, a cylinder side port that can be freely connected to and separated from the single-acting cylinder side, and this cylinder side port and the first valve side port. A first flow path connecting the cylinder side port and the second valve side port, a second flow path connecting the cylinder side port and the second valve side port, and only fluid flow from the cylinder side to the control valve side in one of the first and second connection flow paths. It is characterized in that each of the flow path forming blocks is provided with check valves provided in a blocking state, and the functions and effects thereof are as follows.

In other words, if a single-acting cylinder is connected to the control valve through the block, when fluid is supplied to the cylinder, the check valve will prevent the fluid supplied from the pump from returning to the tank, and the fluid from the cylinder will be prevented from returning to the tank. At the time of discharge, the discharged fluid from the cylinder passes through the first and second connection passages that do not have a check valve, and flows into the return side passage connected to the control valve, while the supply fluid from the pump passes through the one without a check valve. It passes through the check valve and joins the discharge fluid from the cylinder, flows into the return side flow path connected to the control valve, and returns to the tank. Therefore, even single-acting cylinders can be operated without using the safety relief flow path, and equipment equipped with single-acting cylinders can be operated in the same way as equipment equipped with double-acting cylinders. It is now possible to connect and use the fluid without increasing the temperature of the fluid.

Incidentally, if the first and second connecting channels are made of piping, or configured so that they can be connected or removed separately when connecting or removing a single-acting cylinder,
However, by providing these flow path configurations in one block as in the present invention, the piping becomes long and there is a risk of damage due to contact with other equipment, and the time required for installation and removal increases. In addition to making the piping as short as possible, the first and second connecting channels can be connected to and separated from the control valve side all at once, and problems such as damage to the piping and time-consuming connection and detachment of the channels can be eliminated as much as possible. Furthermore, by configuring the block so that it can be connected to and separated from the cylinder side, it can be shared by many connected cylinders, and even if the connecting device is changed, it can be operated with one block at low cost. .

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

As shown in FIGS. 1 and 2, a transmission case 3 forming a self-propelled aircraft body having a pair of left and right front wheels 1, 1 and rear wheels 2, 2, etc., is equipped with a pair of left and right lift arms 4a, 4b is mounted so that it can be driven to swing up and down by a fluid cylinder 5, and a power-mounted shaft 6 is provided, and as shown in FIGS. An agricultural tractor is constructed in which a rotary tiller 8 is connected to the rear part of the machine body so that it can be moved up and down, driven, and separated as shown in FIGS. 3 and 4.

When connecting the ground leveling device 7, please refer to Figures 1 and 2.
As shown in the figure, a ground leveling device frame 7a is connected to the transmission case 3 via a pair of left and right vertically swinging lower links 9a, 9b and a double-acting top link cylinder 10, and one of the lift arms 4a and one lower link 9a are connected by a double-acting lift cylinder 11, the other lift arm 4b and the other lower link 9b are connected by a lift rod 12, and both lower links 9a, The structure is such that the rocking operation of the ground leveling device 7 is performed by the rocking operation of the lower link 9b, and by expanding and contracting the lift cylinder 11, one of the lower links 9a
The ground leveling device 7 swings from side to side with respect to the self-propelled aircraft by swinging and by providing a ball joint (not shown) at the connecting portion of each member.
That is, it is configured so that the left and right working depths can be changed and adjusted, and furthermore, the top link cylinder 10 is extended, and the entire ground leveling device 7 is moved to the lower link 9.
It is configured so that it can be swung around the horizontal axis connected to the ground cutting blades 7b and 9b to adjust the penetration angle of the ground scraping blade 7b and the ground inclination angle of the soil removal plate 7c.

The operating structure of each of the cylinders 5, 10, 11 is constructed as shown in FIG.

That is, the flow path switching valve 1 connected to both the top link cylinder 10 and the lift cylinder 11
3 is detachably connected to a pressure fluid outlet 15 formed in a valve block 14 permanently installed in the mission case 3, and the valve block 14 is
The top link cylinder 10 and the lift cylinder 11 are connected to the manually operated control valve 16 for the double-acting cylinder permanently installed in the pump 17 to take out the supply pressure fluid from the pump 17, and the flow path switching valve 13 is connected to the top link cylinder 10 and the lift cylinder 11. and said control valve 16
The control valve 16 is used to selectively operate the control valve 16. The control valve 18 of the lift arm cylinder 5 is connected to the control valve 16 so that fluid is supplied from the pump 17 only when the control valve 16 is in the neutral position, and the interlocking mechanism 19
The control valve 18 is operated in conjunction with the manual operation lever 20 and one of the lift arms 4b through the oscillator, and the control valve 18 is switched by swinging the operating lever 20, and the swinging motion of the lift arms 4a and 4b is Feedback is provided to the control valve 18 by the interlocking mechanism 19, and the lift arm 4 is moved only by a stroke proportional to the amount of operation of the operation lever 20.
When a and 4b are raised or lowered, the control valve 18 is automatically returned to the neutral position and operated. That is, the ground leveling device 7 can be raised and lowered by position control.

When connecting the rotary tilling device 8, the third
As shown in the figure and FIG.
b. Connecting to the transmission case 3 via a telescopically adjustable top link 21 in place of the top link cylinder 10, and replacing one lift arm 4a and one lower link 9a with the lift cylinder 11; The other lift arm 4a and the other lower link 9b are connected by the lift rod 12, and the rocking operation of both lower links 9a, 9b by the lift arm cylinder 5 causes the tilling device 8 to swing. It is configured to be lifted and lowered.

The tillage device 8 has a ground-contact tail wheel 23 that regulates the depth of the rotary 8b's entry into the ground, by means of a single-acting hydraulic cylinder 25 provided across its swing support arm 24 and the fuselage body 8a. The control valve 18 is equipped so as to be able to swing up and down, and the control valve 18 is connected to the tail wheel 2 regardless of the interlocking mechanism 19.
Operate the operating lever 20 to a position where it is maintained in the lower operating position by touching the ground in step 3, and work while ensuring that the tilling depth is maintained at the set value by the tail wheel 23 regardless of pitching of the tractor. In addition, the setting plowing depth is adjusted by changing and adjusting the mounting height of the tail wheel 25 using the cylinder 23.

In order to enable the operation of the tail wheel cylinder 25, as shown in FIG.
It is separably connected to this, and is also removably attached to the valve block 14, and separably connected to the fluid take-out section 15 via a flow path forming block 26 that is equipped with a flow path and a valve, which will be described later. The supply pressure fluid from the pump 17 is taken out, and the control valve 16 is used as a control valve.

That is, as shown in FIGS. 6 to 8, the block 26 includes the control valve 1.
6, the first and second control valve side ports a, b are separately and separably connected to a pair of cylinder side ports A, B formed in the valve block 14, and from the tail wheel cylinder 25. A cylinder side port c is separably connected to the extended flow path forming pipe 27, and a first valve side port c is connected to the first valve side port a.
A state in which a flow path 28 and a second flow path 29 connecting the cylinder side port c and the second valve side port b are formed, and only fluid flow from the cylinder 25 side to the control valve 16 side is blocked. A check valve 30 provided in the second connection flow path 29 is incorporated. That is, when the tail wheel cylinder 25 is extended, the pressure fluid from the pump 17 is supplied to the cylinder 25 via the first connection flow path 28, and the pressure fluid from the pump 17 is connected to the control valve 16. The check valve 30 prevents the fluid from flowing into the return flow path 31, and when the cylinder 25 is shortened, the discharged fluid from the cylinder 25 flows through the first connection flow path 28 to the return flow path 31. At the same time, the supply pressure fluid from the pump 17 flows into the first connecting passage 28 through the second connecting passage 29 and flows into the cylinder 25.
It merges with the discharged fluid from and flows into the return side flow path 31.

The check valve 30 may be provided toward the first connection flow path 28.

[Brief explanation of drawings]

The drawings show an embodiment of the hydraulic circuit for an agricultural tractor according to the present invention, in which FIG. 1 is a side view of the agricultural tractor connected to the land leveling device, FIG. 2 is a plan view of the connected portion of the land leveling device, and FIG. 3 is the agricultural tractor. 4 is a plan view of the tilling device connection section, FIG. 5 is a fluid pressure circuit diagram when the soil leveling device is connected, FIG. 6 is a fluid pressure circuit diagram when the tilling device is connected, and FIG. 7 is a side view of the tilling device connected state. The figure is a plan view of the flow path forming block, and FIG. 8 is a sectional view of the flow path forming block. 10, 11...Double acting cylinder, 15...Fluid take-out part, 16...Control valve, 25...
...Single acting cylinder, 26...Flow path forming block, 28...First connection flow path, 29...Second connection flow path, 30...Check valve, A, B...Cylinder side port, a , b... Valve side port, c... Cylinder side port.

Claims (1)

[Scope of utility model registration request] A hydraulic circuit for an agricultural tractor permanently installed with a double-acting cylinder control valve 16 for cylinders 10, 11, and 25 that are separably connected to a pressure fluid outlet 15, and for a single-acting cylinder 2.
5 to the control valve 16 side 1
First and second control valve side ports a and b are provided with a flow path forming block 26 that can be detachably attached to the control valve 16 side, and can be separately connected to and separated from the pair of cylinder side ports A and B on the control valve 16 side. , a cylinder side port c that can be freely connected to and separated from the single-acting cylinder 25 side, and this cylinder side port c and the first valve side port a.
a first flow path 28 that connects the cylinder side port c and the second valve side port b, and these first and second connection flow paths 28, 29.
A fluid pressure circuit for an agricultural tractor in which each of the flow path forming blocks 26 is provided with a check valve 30 which is provided on one side of the flow path forming block 26 to block only fluid flow from the cylinder 25 side to the control valve 16 side.