JPH0442971Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a lid structure for inspection of a hydraulic case in an agricultural tractor in which components such as a main cylinder are installed.

[Problems to be solved by the prior art and the invention] Conventionally, the hydraulic case of this type of agricultural tractor contains various parts such as a main cylinder for vertically swinging the lift arm and a control valve mechanism for operating the main cylinder. has been done. For this reason, for example, in a three-point linkage mechanism that raises and lowers a work machine, the top link and left and right lift rods are constructed with hydraulic telescoping cylinders, and by controlling these extensions and contractions, the posture of the work machine can be controlled more precisely. If this is to be done frequently, valve mechanisms such as a flow path priority valve and a control valve for the telescopic cylinder will be required separately from the main cylinder control valve.

However, up until now, all of these various valve mechanisms have been housed inside the hydraulic case, which has required a large hydraulic case. Not only does this go against the development goal of this type of traveling vehicle, which is to make it small and lightweight, but it also poses the drawback that the arrangement of these components inside the hydraulic case, as well as the oil passage piping, etc., creates a complex maze, making assembly, inspection, and maintenance extremely complicated and troublesome, which has been a problem.

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a lid structure for inspecting a hydraulic case of an agricultural tractor that can eliminate these drawbacks. At the top of the hydraulic case housing the main cylinder and its control valve mechanism, an opening is formed through which the main cylinder and control valve mechanism can be viewed from outside the case, and the opening is covered with a removable inspection lid. In addition, a flow path priority valve separate from the control valve mechanism and a control valve for a telescopic cylinder that constitutes a three-point link mechanism and a lift rod are attached to the inner and outer surfaces of the inspection lid, and the inspection lid is also fitted with The valve mechanism is characterized in that oil holes are bored therein to form oil passages for each of these valve mechanisms.

The hydraulic cylinder is then fitted with a valve mechanism separate from the control valve mechanism for the main cylinder. This valve mechanism can be attached by effectively utilizing the inspection cover of the hydraulic case. This makes it possible to avoid making the hydraulic case unnecessarily large, and prevents the interior of the hydraulic case from becoming a complex maze of arrangements and piping, while also making the hydraulic case easier to assemble, inspect, and maintain.

[Example] Next, an example of the present invention will be described based on the drawings. In the drawing, reference numeral 1 denotes a running body of an agricultural tractor, and a plow 4, which is a towing work machine, is attached to the rear of the running body 1 via a three-point linkage mechanism consisting of a top link 2 and a lower link 3. . Further, 5 is a lift arm, and 6 is a lift rod, and the lift rod 6 and the top link 2 are respectively constituted by telescopic cylinders 6a and 2a.

7 is a hydraulic case in which the present invention is implemented,
Inside the hydraulic case 7, a main cylinder 8,
The control valve 9, an operating arm 10 connected to the cylinder rod 8a of the main cylinder 8, and a lift arm shaft 11 are installed inside the hydraulic case 7, and the rear part of the hydraulic case 7 receives the draft force from the plow 4 in the longitudinal direction. Top link 2 to go directly to
An actuating rod 13 is interlocked with the actuating rod 13 via a link receiver 12, and an actuating bullet 14 that elastically supports the actuating rod 13 is attached so as to penetrate therethrough. A guide arm 15 provided therein, and a long hole 1 bored in the guide arm 15.
A draft force detection sensor 16 consisting of a potentiometer in which a rotating shaft portion 16a is slidably fitted into 5a converts the linear movement of the guide arm 15 according to the draft force into a rotational movement of the rotating shaft 16a. a link mechanism 17 that connects the operating arm 10 and the height detection sensor 18 of the work equipment;
Various members such as a are assembled.

Furthermore, an inspection window W is provided on the top surface of the hydraulic case 7 through which the main cylinder 8 and its control valve 9 can be seen from outside the case, and this inspection window is covered by a detachable inspection lid 19. It is blocked. The lower surface (inner surface) of this inspection lid 19
includes an inching control valve 20 and the telescopic cylinder 2.
Control valves 22 and 23 for a and 6a are installed on the upper surface (outer surface), and a flow priority valve 21 is installed on the top surface (outer surface), and the inspection lid 19 is equipped with these as described below. Oil holes 19a are appropriately drilled to form oil passages for connection.

FIG. 5 also shows various valves 9, 20, 21, 2 of the control valve mechanism etc. when the plow 2 is installed.
2 and 23 are shown, and here, 24 is a control section consisting of a microcomputer, and the control section 24 includes a height detection sensor 18, a draft force detection sensor 16, and a plow. 2
Detection signals from the horizontal detection sensor 25 and the length detection sensors 2b, 6b of the telescopic cylinders 2a, 6a, as well as the draft setting device 26, work equipment height setting device 27, inclination angle setting device 28, and top link. Each setting signal from the length setter 29 is inputted from the corresponding input terminal, calculated, and sent to one drive circuit 30 for the main cylinder or the other drive circuit 31 for other cylinders. It outputs control commands and performs necessary posture control of the plow 2. Here, the other drive circuit 31 outputs an inching signal when the length of the telescopic cylinders 2a, 6a approaches the set length by switching the corresponding control valve, and the inching control valve 20 This causes the telescopic cylinder 2 to move by an inch.
The expansion and contraction speeds of a and 6a are reduced, allowing accurate and shock-free stopping.

In the embodiment of the present invention configured as described above, the working posture of the plow 2 is determined by each detection sensor 6b,
2b, 16, 17, 18, 25 and setting signals from setting devices 26, 27, 28, 29 are input and processed by the output signal from the control section 24, which controls the corresponding control valve 9. ,22,2
3 is switched via the drive circuit 31 or 30 and automatically controlled.

In this way, in this embodiment, in addition to the control valve 9 for the main cylinder 8, there is an inching control valve 20, a flow path priority valve 21, and a control valve 2 for the telescopic cylinders 2a and 6a.
Various control valve mechanisms such as 2 and 23 will be provided, and these various valve mechanisms are installed by effectively utilizing the inner and outer surfaces of the inspection lid 19 that is detachably provided on the hydraulic case 7. Therefore, not only is it easier to assemble these valve mechanisms, but it is no longer necessary to secure installation space for the various valve mechanisms in the hydraulic case, and they can be arranged compactly so that they overlap around the inspection lid 19. become.

As a result, the inspection window W may be large enough to allow viewing of the main cylinder 8 and its control valve 9, and by removing the inspection lid 19,
The main cylinder 8 and its control valve 9 housed in the hydraulic case 7 as well as various valve mechanisms attached to the lid body 19 can be inspected and maintained, and maintainability is greatly improved.

In addition, when upgrading a model and installing multiple valve mechanisms in addition to the conventional main cylinder control valve 9, these valve mechanisms can be installed on the inner and outer surfaces of the inspection lid 19. By installing it, the arrangement inside the hydraulic case does not become complicated.
Moreover, since the installation space for the valve mechanism can be secured in the gap around the inspection lid 19, there is no need to make the inspection window W large or to make the hydraulic case particularly large. Furthermore, in the present invention, the oil hole 19a drilled in the inspection lid 19 forms an oil passage connecting each valve mechanism. Despite the provision of multiple valve mechanisms, the piping configuration of the oil passages is simplified, and therefore the assembly and inspection and maintenance of these various parts cannot be easily and easily performed, and the pressure loss in the hydraulic circuit is It has the advantage of being able to measure significant reductions.

Although FIG. 5 shows the hydraulic control circuit mechanism when the plow 2 is attached, FIG. 6 shows the hydraulic control circuit mechanism when the rotary tiller 32 is installed as a working machine. In this case, since a draft control mechanism is not required, the equipment for the draft control mechanism is not shown, but in the control unit 24, a depth detection sensor 33 that detects the plowing depth instead of draft detection is used. An input terminal that receives input from the hydraulic pump P and an output terminal that issues a control command to the flow divider 34 that divides the oil path from the hydraulic pump P before reaching the flow path priority valve 21 are shown, respectively. In addition to controlling the tilling depth, when moving the rotary tilling section 32 up and down when the machine is rotating, etc.
The flow divider 3
4 is activated, the hydraulic clutch 35 is switched on and off, thereby controlling the power transmission from the engine E to the rotary tiller 32 on and off.

[Operations and Effects] In summary, since the present invention is constructed as described above, various control valve mechanisms such as the flow path priority valve and the control valve for the telescopic cylinder provided in addition to the control valve for the main cylinder are Since the inspection lid, which is removably provided on the hydraulic case, can be installed by effectively utilizing the inner and outer surfaces of the inspection lid, not only is it easier to assemble these valve mechanisms, but it is also easier to assemble various valve mechanisms. There is no need to secure an installation space within the hydraulic case, and the inspection lid can be arranged compactly so that it overlaps the inside and outside of the lid.

Moreover, the inspection window formed on the top surface of the hydraulic case only needs to be large enough to allow viewing of the main cylinder and its control valves. In addition to the cylinder and its control valve, various valve mechanisms attached to the lid can be inspected and maintained, greatly improving maintainability.

In addition, when upgrading a model and installing multiple valve mechanisms in addition to a conventional main cylinder control valve, these valve mechanisms can be installed in an inspection lid body with oil passages. By installing it on the inner and outer surfaces of the inspection window, the arrangement inside the hydraulic case does not become complicated, and the installation space for the valve mechanism can be secured in the gap around the inspection lid. There is no need to make it large or to make the hydraulic case particularly large.

[Brief explanation of the drawing]

The drawings show an embodiment of the inspection lid for the hydraulic case of the agricultural tractor according to the present invention, in which Fig. 1 is an overall side view of the agricultural tractor, and Fig. 2 is a vertical sectional view of the main parts of the hydraulic case. , Fig. 3 is a view in the direction of arrow A in Fig. 2, Fig. 4 is a plan view of the main parts of the hydraulic case, Fig. 5 is a hydraulic control circuit diagram when a plow is attached,
FIG. 6 is a hydraulic control circuit diagram when a rotary tiller is attached. In the figure, 7 is a hydraulic case, 9 is a control valve, 19 is an inspection lid, 19a is an oil hole, 20, 21, 22, 2
3 is a valve mechanism.

Claims (1)

[Scope of utility model registration request] An inspection window is formed in the upper part of the hydraulic case that houses the main cylinder and its control valve mechanism from outside the case, and the inspection window is covered with a removable inspection lid. , various control valve mechanisms such as a flow path priority valve separate from the control valve mechanism and a control valve for a telescopic cylinder constituting a three-point link mechanism and a lift rod are installed on the inner and outer surfaces of the inspection lid; The inspection lid structure for a hydraulic case of an agricultural tractor is further characterized in that the inspection lid is provided with oil holes that form oil passages for these various valve mechanisms.