CONTROL VALVE

TECHNICAL FIELD

The present invention relates to control valves which control lifting and lowering functions of hydraulic lifters provided in tractors.

PRIOR ART

In tractors, there are hydraulic lifters generally at the rear part of the tractor. There are control valves in order to control the lifting and lowering functions of hydraulic lifters.

During operation of the control valves, beginnings of lifting and lowering movement and staying in neutral position bear great importance. A main slide, provided inside the control valve, is moved and the functions of the control valve are controlled. The steps provided on the main slide open or close the front of the flow lines provided at the body of the control valve. Thus, dimension precision is very important during formation of main slide and flow lines.

For instance, in the present art, the main slide provided in the body opens and closes a flow line extending towards a discharge valve. Accordingly, the width of the step provided on the main slide and the diameters of the flow line shall be provided in a suitable manner. While it is possible to produce the step, provided on the main slide, with precise dimensions, measurement precision cannot be provided in the flow line drilled by the drill due to deflection occurring in the drill. This condition leads to not controlling of the flow line in a suitable manner and not working of the control valve in a firm manner. Moreover, since dimensional problems occur at the inner sections of the body, fault detection cannot be realized by making measurement, and therefore, faults can only be detected during usage. This leads to increase of the fault costs.

As a result, because of all of the abovementioned problems, an improvement is required in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a control valve, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

An object of the present invention is to provide a control valve which prevents problems resulting from dimensional errors which may occur in the flow line.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a control valve, for hydraulic lifters used on tractors, and having a body, a main slide provided in a slide opening inside the body and at least one flow line which intersects with the slide opening. Accordingly, the subject matter control valve comprises at least one peripheral channel which extends in a manner encircling the slide opening at the intersection of the slide opening and the flow line and whose width is provided to be greater than the diameter of the flow line.

Moreover, the present invention is a production method for a control valve with said properties. Accordingly, the following steps are provided: forming the peripheral channel by means of at least one lathe holder extending inwardly through the slide opening, and drilling the flow line by means of a drill having a diameter smaller than the width of the peripheral channel.

BRIEF DESCRIPTION OF THE FIGURES In Figure 1 , a representative schematic view of the subject matter control valve is given. In Figure 2, a representative detailed view of the subject matter control valve is given. In Figure 3, another representative detailed view of the subject matter control valve is given.

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter control valve (10) is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable. The subject matter control valve (10) has a body (20) and at least one main slide (30) provided inside said body (20). The main slide (30) is positioned in a slide opening (21 ). There is at least one flow line (22) which interrupts said slide opening (21 ). A step (31 ), provided on the main slide (30), is provided at a width which prevents fluid passage through the flow line (22) which provides control of a discharge valve (24) in accordance with the position of the main slide (30).

In the subject matter control valve (10), there is a peripheral channel (23) provided in the region where intersection occurs between the flow line (22) and the slide opening (21 ). The peripheral channel (23) is essentially provided in the form of a circular channel which encircles the slide opening (21 ).

As can be seen in Figure 2, in the subject matter control valve (10), first of all, the slide opening (21 ) is opened in order to obtain the peripheral channel (23), and afterwards, the peripheral channel (23) is formed by means of a lathe holder (50) extending inwardly through the slide opening (21 ). Thus, the peripheral channel (23) is formed in precise dimension. In other words, the beginning, ending and channel width can be processed in a precise manner depending on the step (31 ) which is provided at the main slide (30). Afterwards, as can be seen in Figure 3, a flow line (22) is drilled with a diameter, which is smaller than the width of the peripheral channel (23), with the help of a drill (40). Thus, while the peripheral channel (23) is being processed in a substantially precise manner, there remains no need to process the flow line (22) with high precision.

Besides, burr formation at the edge parts is prevented by forming the peripheral channel (23), provided at the intersection of the slide opening (21 ) and the flow line (22), by means of the lathe holder (50).

The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention. REFERENCE NUMBERS

10 Control valve 20 Body

21 Slide opening

22 Flow line

23 Peripheral channel

24 Discharge valve 30 Main slide

31 Step

40 Drill

50 Lathe holder