CH714022A1 - Hydraulic device, in particular hydraulic valve or hydraulic regulator. - Google Patents

Abstract

The present invention relates to a hydraulic device, in particular a hydraulic valve or hydraulic regulator, with a housing (14) and at least one piston (17) axially displaceably mounted in a housing bore and at least one pressure spring (18) acting on the piston (17) at least one externally accessible adjusting screw (20) within the housing bore for adjusting the bias of the compression spring (18) in the axial direction is adjustable, wherein the at least one screw (20) is screwed directly to an internal thread of the housing bore and the screw (20) at the same time Closure system for sealing the spring chamber (18a, 18b) forms to the outside.

Description

Description: The invention relates to a hydraulic device, in particular a hydraulic valve or a hydraulic regulator, with a housing, a piston which is axially displaceably mounted in a housing bore and at least one compression spring acting thereon.

In the following explanation, in the text passages in which the disclosure of the invention relates to the application of the features of the invention to hydraulic regulators, the term piston used in this environment is used instead of the generalized term piston. In the text passages in which the disclosure of the invention relates to the application of the features of the invention to hydraulic valves, the term control spool used in this environment is used instead of the generalized term piston. The term piston is continued in the general parts of the text.

The features of the invention can be applied to all different types of hydraulic regulators, e.g. Pressure regulators, power regulators, volume flow regulators etc. and on all different types of hydraulic valves e.g. Pressure relief valves, proportional valves etc. To clarify the general applicability of the features of the invention, the content already contained in the previous sentence should be emphasized that the features of the invention can be applied to hydraulic regulators and hydraulic valves regardless of whether the hydraulic device has additional control inputs or not. The term control input is to be understood here as an additional possibility of engagement to apply a further force effect to the piston which is axially displaceably mounted in a housing bore. This could e.g. an additional oil connection to another control surface of the piston, an actuator (e.g. a proportional magnet) with which a force effect can also be exerted on the piston etc.

A pressure regulator can be used to operate a hydraulic displacement unit, for example a hydraulic pump. If the pressure regulator has an additional control input, the oil pressure present at the high pressure output of the hydraulic pump can be regulated to a certain level depending on the control signal supplied via it; of course, provided that sufficient mechanical power can be supplied to the hydraulic pump. The pressure level must exceed a minimum value in order to maintain an oil leak necessary for self-lubrication of the hydraulic pump or the hydraulic system. At the same time, the pressure level at the high-pressure outlet of the hydraulic pump must be limited to an upper value in order to avoid overloading it or that of the components of the hydraulic system. This compliance with a limitation of the pressure range on both sides - often referred to as pressure cut-off on both sides - is also necessary for a hydraulic motor operating in pump operation. In practical use, this operating mode is, for example, in the braking mode of a hydraulic travel drive or when lowering a load from a winch operated by a hydraulic motor.

By changing the bias of the compression spring via an externally accessible adjusting screw, the lower and the upper limit pressure can be set in relation to the example of a pressure-controlled hydraulic pump. Pressure control is then possible within the range between these limit pressures. Provided that sufficient mechanical power can be supplied to the hydraulic pump, the pressure level at the high-pressure outlet of the hydraulic pump does not drop below the lower limit pressure. It is not possible to exceed the upper limit pressure.

Fig. 1 shows a longitudinal section of a controller axis equipped with the components using the example of a controller main stage. The left part of this illustration, starting with the spring plate 3a arranged between the control piston 1 and the helical spring 2, shows a mechanism for adjusting the spring preload known from the prior art. The construction is based on a multi-part adjustment system, which is introduced into the controller housing 4 and consists of the set screw guide sleeve 5 and the actual set screw 6 for changing the pretension of the coil spring 2. In the embodiment shown, the set screw guide sleeve 5 screwed into the controller housing 4 represents a lining of the spring chamber 9 The right-hand collar of the adjusting screw guide sleeve 5 forms the end stop of the spring plate 3a and thus also acts as an end stop of the control piston 1. Since the position of this collar is independent of the screwing depth of the adjusting screw 6, this results in a final fixed minimum value for the lower pressure cut-off. The left area of the set screw 6 is guided to the outside via a threaded connection to the set screw guide sleeve 5. This enables the setting of different preloads of the helical spring 2 and thus the presetting of a certain pressure cut-off, which is however freely adjustable within a certain bandwidth.

In order to prevent the automatic adjustment, the set position of the screw 6 is fixed by means of a lock nut 8. The fixation by means of the lock nut 8 always leads to an unavoidable slight change in position of the adjusting screw 6 and thus to an influence on the pretension and thus on the actual pressure cut-off. This error can only be compensated for by deliberately deviating from the set position of the adjusting screw 6, which is then ideally compensated for by the subsequent fixation of the lock nut 8 caused by the adjustment. With this procedure, a sufficiently precise setting of the pressure cut-off can be achieved on a regulator main stage with a little patience and practice. In contrast, the exact setting of a load-sensing pressure value on a load-sensing controller using the construction presented is quite lengthy and yet imprecise.

CH 714 022 A1 The object of the present invention is to simplify the known adjustment system for adjusting the pretension of a compression spring according to the prior art, in particular the problems mentioned with regard to the necessary compensation of the fixation by means of a lock nut are to be avoided. In addition, a simplified and particularly inexpensive solution for the adjustment system is sought.

This object is achieved by a hydraulic device according to the features of claim 1. Advantageous embodiments of the device are the subject of the dependent claims. Furthermore, the object is also achieved by a hydraulic device according to the features of claim 2. Advantageous embodiments of this device are also the subject of the dependent claims.

For the sake of simplicity, the solution according to the features of claim 1 and its advantageous embodiments will first be discussed. Starting from the generic hydraulic device according to claim 1, in particular the hydraulic valve or hydraulic controller, it is proposed according to the invention that the set screw is directly engaged with an internal thread of the housing bore of the housing of the device. As a result, the set screw sleeve known from the prior art can be dispensed with, instead the set screw is received directly through a suitable threaded bore within the housing of the hydraulic device. In addition, a lock nut which is located coaxially on the set screw is also not necessary for fixing the set screw. Another advantage of the invention is that the set screw also serves as a locking system for the pressure-tight and oil-tight closing of the spring chamber to the outside.

As already mentioned above, the device can be a hydraulic valve or a hydraulic controller. Several valve elements or controller axes can be accommodated in a common housing. The valve element here is understood to be the arrangement of an adjusting slide with a compression spring, a regulator axis comprises a control piston and at least one compression spring. With such hydraulic devices in the housing of which several valve elements / regulator axes are installed, the adjusting screws of the valve elements / regulator axes do not necessarily have to be identical, but instead can differ from one another in one or more features, be it a combination of different embodiments according to the invention or not there is a combination of embodiments according to the invention with designs that already correspond to the prior art, for example a twin housing which houses a load-sensing controller according to the invention and a stage for pressure cut-off corresponding to the prior art.

For such spring chambers provided with a pressure connection, the approach according to the invention allows a much simpler and less expensive construction of the hydraulic device, with which the problem discussed above is additionally avoided.

The adjusting screw plug can include the spring plate that forms the stop of the compression spring. The spring plate can be formed as a separate component or also by an extension of the locking screw.

According to a preferred embodiment of the invention, at least one radial groove is provided on the lateral surface of the set screw into which at least one sealing element, e.g. in the form of an O-ring. This ensures a sufficient sealing effect of the set screw even up to a certain oil pressure within the spring chamber. A support ring can also be introduced into the radial groove to increase the pressure density. In particular, the support ring, starting from the spring chamber, sits directly behind the sealing element in a common radial groove.

A fixing or fixing of the set screw, in particular in order to avoid undesired adjustment of the set screw, can be done by means of a locking element which presses perpendicularly onto the lateral surface of the set screw. For this purpose, a clamping screw is preferably screwed perpendicularly to the adjusting screw into a suitable threaded hole in the housing of the hydraulic device, which braces the outer surface of the adjusting screw against the housing.

To limit the travel of the set screw, be it to define a maximum or minimum preload of the compression spring, as well as to secure the set screw against unintentional unscrewing, particularly preferably at least one locking element, ideally at least one shaft locking ring, the travel of the Set screw limited. At the same time, this securing element effects a sufficient blocking of the inner area of the housing bore in order to prevent the set screw from shooting out in the event of a possible breakage of material, in particular damage to the thread, in the event of a damage that cannot be completely excluded.

Here there is the possibility of fastening the shaft locking ring in an inner radial groove in the outer region of the housing bore. The shaft locking ring defines a stop that blocks further unscrewing of the set screw from the housing bore, in particular the further unscrewing, which is accompanied by a loss of the sealing effect or the complete falling out of the set screw from the housing of the hydraulic device, is prevented. When the device is designed as a load-sensing controller with pressure cut-off, the positions of the shaft locking ring in question can be defined to determine the lowest possible setting values for the load-sensing pressure and the cut-off pressure.

Alternatively, there is the possibility of attaching at least one locking ring to the outer surface of the set screw itself, preferably within an outer radial groove provided in the outer surface. Even if the shaft locking ring is partially inside the outer radial groove, this forms ge opposite to the set screw

CH 714 022 A1 with a slightly larger diameter an axial stop. For example, it can be provided that the outer radial groove and the shaft locking ring introduced into the radial groove lie within the spring chamber of the housing. The shaft retaining ring forms a stop in relation to the tapering of the diameter of the inner bore at the end of the spring chamber, i.e. the set screw can only be unscrewed from the housing bore until the shaft retaining ring strikes the end wall of the spring chamber. The position of the outer radial groove, more precisely the position of the end of the outer radial groove on the side facing away from the piston, and that of the shaft locking ring determine the minimum preload of its compression spring for the respective structure of a hydraulic device.

It is also conceivable that a dedicated annular recess is provided within the housing or within the housing bore. A shaft locking ring seated on the set screw lies within the annular recess and strikes at the ends thereof with the adjacent longitudinal section of the housing bore, which has a smaller diameter. The width of the annular recess in the axial direction defines a stop in both axial directions, as a result of which a minimum and maximum prestress of the compression spring can be firmly defined. The arrangement of the annular recess in the region of the end of the adjusting screw facing the spring chamber is particularly preferred. As an alternative, however, there is also the possibility of this in the area of the bore opening, i.e. to be arranged in the region of the end of the set screw facing the bore opening.

A limitation of the maximum screw-in depth can, however, not only be achieved by means of the shaft retaining ring, but also by a tapering of the diameter of the housing bore, forming a shoulder or stop. As a result, the set screw can be screwed in until the shoulder is reached. It is particularly preferred if the inner diameter area that adjoins the shoulder tapers conically. Ideally, the selected taper of the inner bore corresponds to the taper of an assigned counter stop surface of the set screw jacket surface. As a result, when the set screw reaches this stop position, an otherwise existing point load is avoided; instead, the load on the set screw and housing is distributed over a large area, which significantly reduces wear on the active surfaces.

[0021] According to a preferred embodiment of the invention, the entire adjustment path of the adjustment screw can be divided into at least two adjustment ranges. Different adjustment ranges are characterized by a different screw-in depth of the set screw. For example. is the set screw for a first number of screw turns within a first adjustment range. From a defined screw-in depth, the set screw moves into a second or subsequent adjustment range. The torque to be used for actuating the adjusting screw is particularly preferably noticeably different in the different adjustment ranges. The torque to be used is preferably higher in the second adjustment range with a greater screw-in depth of the set screw than in the first adjustment range with a smaller screw-in depth. The torque to be used is preferably higher in the third adjustment range with an even greater screw-in depth of the set screw than in the second adjustment range, etc. What is essential is a change in the torque required for the technician to actuate the set screw, which signals a tactile feedback signal to the technician with regard to the screw-in depth reached can. The adjustment ranges are characterized by different screw-in depths and consequently different ranges of the pre-tensioning of the compression spring.

The application of these features of the invention using the example of the pressure cut-off of a hydraulic pump provides that there are two different setting ranges on the hydraulic device for setting the maximum pressure which can occur at the high-pressure outlet of the hydraulic pump. Is the hydraulic system tuned, i.e. If the hydraulic pump, the regulators and valves used, the hydraulic consumers etc. are matched to one another, then setting within the first adjustment range means that the said maximum pressure is within the permissible regular pressure range in which the hydraulic system can be operated continuously, whereas this Setting within the second range allows the hydraulic system to operate in a temporarily permissible overload range. In order to signal the present adjustment range to the technician when the adjusting screw is actuated, the torque to be used in the second range is noticeably higher.

According to a preferred embodiment, a first adjustment range is defined by the movement of a first sliding surface of the set screw along a first length section of the housing bore, while at least one further adjustment range is defined by the movement of a second sliding surface of the set screw along a second length section of the housing bore. In a preferred embodiment, is defined by the movement of a sliding surface of the set screw along a first length section of the housing bore, while a second adjustment range is defined by the movement of the same sliding surface of the set screw along a second length section of the housing bore that deviates from the first length section.

In principle, any number of different adjustment ranges can be provided.

It is possible that the sliding surface in the first adjustment area slides almost frictionlessly along the first length section, while in the second adjustment area there is an interference fit between the sliding surface of the set screw and the second length section of the inner bore. The resulting increasing mechanical friction between the adjusting screw and the longitudinal section causes a greater torque to be used for actuating the adjusting screw.

CH 714 022 A1 In addition, it can be provided that the housing of the hydraulic device is provided with at least one protective cap, which can be detachably fixed to the housing to cover the at least one adjusting screw plug. The protective cap can be attached by means of one or more claws which are pronounced on the protective cap. These claws engage in complementary recesses in the housing, so that there is a positive connection between the protective cap and the housing. It is particularly advantageous if the claws or other components of the protective cap are provided with corresponding predetermined breaking points, so that the protective cap cannot be detached from the housing without being destroyed. This ensures that a change in the pretension of the spring element or elements is immediately apparent from the absence or the defective protective cap. It is also possible to equip the system with different protective caps, for example differently colored protective caps. The optical design of the protective cap can then be used to signal when or by whom a corresponding change in the preload of the piston spring has been made. In the case of hydraulic devices with several valve elements or several controller axes within a common housing, the protective cap can cover several adjusting screws.

Furthermore, it can be provided that the adjusting screw comprises a narrowing jacket section, which is preferably of a conical shape, to which a pin, displaceably mounted perpendicular to the axial direction of the adjusting screw, adjoins, which via a prestressed compression spring on a jacket section surface of the adjusting screw is pressed, which has a non-cylindrical shape. As a result, the position of the support point of the pin is dependent on the screw-in depth of the set screw. The position dependency is limited to the axial direction of the pin perpendicular to the axial direction of the set screw. This surface section surface of the set screw is preferably conical. The position of the pen is used as a haptic-optical indicator for the pre-tensioning of the compression spring set by means of the adjusting screw. In this context, it is expedient if the pin protrudes from the housing of the device through a corresponding opening so that it is visible from the outside. If there is an installation situation of the hydraulic device (e.g. a controller) in the higher-level system, e.g. a mobile machine, where the pin is not visible, its axial position can be recognized by manual scanning.

The task of offering a simplified and inexpensive solution is solved by a hydraulic device according to the features of claim 2. Here, too, the device can be designed as a hydraulic valve or hydraulic controller, wherein designs with a plurality of valve elements or controller axes as described above are possible.

The inventive hydraulic device according to claim 2 provides a plug instead of a one-piece adjusting screw. The sealing plug still fulfills the sealing function described above to prevent such hydraulic oil from the spring chamber of the hydraulic component from escaping from the housing of the hydraulic device. Accordingly, the sealing plug must be equipped with a sealing system.

This can preferably be done in the same way as in the one-piece locking screw by a corresponding annular recess on the outer surface of the sealing plug and the installation of an O-ring there or by an O-ring resting on a support ring. In contrast to a construction of the hydraulic device, which contains a one-piece adjusting screw plug, there is no threaded connection for a construction using a sealing plug between the latter and the housing bore.

The plug is preferably fixed axially in the housing bore with a component. A possible embodiment of this fixation, hereinafter referred to as variant 1, can be achieved by making an internal radial groove in the housing bore. This inner radial groove is preferably located on the side of the housing bore facing away from the spring chamber, specifically at the position that directly adjoins the area of the housing bore that is filled by the sealing plug. At least one shaft locking ring can be inserted into this inner radial groove. When installing the sealing plug in the housing bore, the plug can be pushed in further than its intended end position in the direction of the spring chamber by means of an appropriate tool. The shaft locking ring can then be inserted into said radial inner groove. If said tool is removed, the end of the sealing plug is pressed against the shaft locking ring by the restoring force of the compression spring. This means that there is a clear axial position of the assembled sealing plug.

The sealing plug can include the spring plate in the same way as the one-piece adjusting screw.

The use of the sealing plug allows the pretension of the compression spring to be changed only by component changes (e.g. an exchange or the addition or removal of components). For example. Various sealing plugs adapted to the prestress of the compression spring required can be used, of which the appropriate sealing plug is used for each desired prestress. The adjustment can be made via the component dimension between the contact surface to the shaft retaining ring and the contact surface of the compression spring. Advantageously, this is done by manufacturing identical blank plugs with a corresponding oversize. The component dimensions required for individual adaptation are created in post-processing.

CH 714 022 A1 In all of the alternatives described below, the finished sealing plug can be designed as the same part because the individually required pretension of the compression spring is achieved by other measures. For example, compression springs adapted due to their different lengths can be used, the spring constant (spring hardness) having to have the same value in all cases. Alternatively, it is conceivable to use spring plates with different, adapted plate thicknesses. This can be a spring plate which is arranged between the piston and the compression spring. Alternatively, a separate spring plate could also be applied to the sealing plug, the plate thickness of which is dimensioned according to the pretension required. The arrangement of a spring plate detachably attached to the sealing plug is particularly preferred, so that a suitable spring plate with the appropriate thickness for the desired preload can be selected as required.

Alternatively, a customized piston could also be used. The portion of the piston located towards the spring chamber could be beyond the functional range of a control chamber of the device (e.g. beyond an annular recess in the piston, which is used to create the required oil connections between different stages within the hydraulic device (for example between a preliminary and main stage of a two-stage hydraulic regulator) and also to create the required oil connections to the external connections of the device) have different lengths which are decisive for the pretensioning of the compression spring.

In a preferred embodiment, one or more washers can be placed between the compression spring and one of its support surfaces or on both support surfaces in order to achieve the required prestressing of the compression spring. This can be the contact surface of the spring plate located at the end facing the piston or the spring plate on the side of the sealing plug, which, as mentioned, can be formed as a separate component or also by an extension of the sealing plug. To achieve a certain preload, a single washer that exactly matches the thickness of the washer or several washers that match the overall thickness can be used. Alternatively or additionally, the thickness of the washers can be installed between the shaft locking ring and the end of the sealing plug.

In an advantageous embodiment, both contact surfaces for the compression spring consist of a hardened material by hardening the entire component or hardening the relevant surface areas or a suitable coating of the entire component or a suitable coating of the relevant surface areas.

In a particularly advantageous embodiment, one or both of these hardened bearing surfaces of the compression spring are represented by the use of hardened washers. This has the advantage that materials with a much lower hardness can be used for the more complex components.

In the preferred embodiment, two hardened washers of a standard size are used as contact surfaces of the compression spring and the adjustment of the compression spring that is specifically required is achieved by using additional washers that are adapted to their washer thickness. These adapted washers are advantageously used between the shaft locking ring and the sealing plug. With this design, the dimension by which the prestress of the compression spring can be varied in the intended adjustment range can be measured directly from the outside without having to remove the hydraulic device. Likewise, the hydraulic device does not have to be removed to change the pretension of the compression spring.

Instead of using an inner radial groove for the shaft retaining ring, according to an alternative embodiment of the invention, hereinafter referred to as variant 2, the sealing plug can have an outer radial groove within its outer surface, into which a shaft retaining ring is inserted. During assembly, the shaft retaining ring is first inserted into the outer radial groove before the sealing plug is inserted into the housing bore.

The dimensions of the outer radial groove and that of the shaft retaining ring are designed so that the sealing plug can be inserted into the housing bore when the shaft retaining ring is in place. This affects i.a. the coordinated dimensions of the groove and those of the relaxed shaft locking ring and the width to which the shaft locking ring can be compressed as intended. In a coordinated position, the housing bore has a dedicated ring-shaped recess, the dimensions of which are in turn designed such that as soon as the shaft locking ring placed on the outer radial groove of the sealing plug reaches the ring-shaped recess, it snaps into place and remains in this position.

With the exception of the use of washers in the housing bore outside the area closed by the sealing plug, all of the above-mentioned possibilities can also be used for variant 2 for preparation, so that when the sealing plug is inserted into the latching position, the prestress of the compression spring is required , Accordingly, in an advantageous embodiment, the contact surfaces of the compression spring can be implemented by hardened washers of a standard size and the adjustment of the prestressing of the compression spring within the adjustment range can be achieved by using washers of suitable thickness, so that the more complex components are independent of the required prestressing of the compression spring Identical parts can be executed.

In variant 2, the sealing plug can obviously not be removed after its installation in the hydraulic device. This has the advantage that unauthorized opening of the hydraulic device

CH 714 022 A1 or the incorrect adjustment of the pre-tension of the compression spring per se. Clearly, however, is a proper subsequent adjustment of the bias of the compression spring, respectively. a subsequent adjustment of the hydraulic device impossible.

In a further advantageous embodiment of the hydraulic device, hereinafter referred to as variant 3, the sealing plug near the end facing the spring chamber has an outer radial groove within its lateral surface, into which a shaft locking ring is placed before assembly. The dimensions of this outer radial groove and that of the shaft locking ring are designed so that the sealing plug can be pushed into the housing bore when the shaft locking ring is pushed on and compressed as intended.

With appropriately designed dimensions, the shaft retaining ring is further compressed when passing through a narrowing section of the housing bore, which is preferably conical, and can finally plunge into the spring chamber. In the interior of the spring chamber or at least in a first section, the housing bore has a larger inside diameter, so that the shaft locking ring can expand again. This inner diameter is preferably large enough for the shaft locking ring to expand to the diameter at which there is no longer any mechanical tension, i.e. assumes the diameter that the shaft locking ring has as a loose unobstructed component. There is an abrupt change in the inner diameter between the end region of the narrowing section of the housing bore that is in focus at the moment of observation and the spring chamber. This measure ensures that the sealing plug can no longer be removed as soon as the shaft locking ring is completely immersed in the spring chamber.

In the described advantageous variant 4 of the hydraulic device, the housing bore between the area in which there is that narrowing of its inner diameter, which brings about the desired compression of the fitted shaft locking ring when the sealing plug is installed, and the spring chamber has an inner radial groove. As soon as the shaft locking ring is completely immersed in said inner radial groove, the sealing plug can no longer be removed.

The invention also relates to the use according to the invention of the hydraulic device according to the invention, both in the version with a locking screw and in the version with a plug, for pressure cutoff in a hydraulic system, in particular for pressure cutoff when operating an axial piston pump or an axial piston motor.

It is also conceivable to use the hydraulic device, both in the version with a locking screw and in the version with a plug, as a pressure relief valve for limiting the maximum pressure level within a hydraulic system.

Furthermore, the present invention relates to a hydraulic system comprising at least one axial piston motor or at least one axial piston pump and at least one hydraulic device, both in the version with an adjusting screw plug and in the version with a plug, designed as a hydraulic controller according to the present invention, which is connected to an axial piston pump or an axial piston motor for pressure cut-off. The advantages and properties of the hydraulic device according to the invention therefore also apply without restriction to the hydraulic system or the use of the device according to the invention, which is why a repeated description is not given here.

Furthermore, the present invention relates to a hydraulic system comprising at least one hydraulic device, both in the version with a locking screw and in the version with a plug, in the form of a hydraulic valve according to the present invention. For example. the hydraulic valve is used to limit the pressure of the system within the hydraulic system.

Further advantages and properties of the invention will be explained in more detail below with reference to an embodiment shown in the figures. It shows:

1: a conventional main stage of a multi-stage hydraulic controller,

2 shows a sectional illustration of the hydraulic device according to the invention in the form of a two-stage hydraulic regulator, of which each stage is equipped with an adjusting screw plug according to the invention

3: a detailed view of the hydraulic controller of FIG. 2,

4: a perspective sectional view of the hydraulic regulator according to FIG. 2,

5: a further detailed view of the hydraulic controller according to FIG. 2,

6: a detailed view in section of the hydraulic device according to the invention according to a second alternative embodiment,

CH 714 022 A1

7: representations of the locking screw according to FIG. 6 during different phases during assembly in the hydraulic device,

8: a detailed view in section of the hydraulic device according to the invention according to a third alternative embodiment variant,

9: a detailed view in section of the hydraulic device according to the invention according to a third alternative embodiment,

10: a sectional view of the optional optical-haptic monitoring component (type A),

11: detailed views of the optical-haptic monitoring component,

12 shows a sectional illustration of the optional optical-haptic monitoring component according to a first variant (type B),

13: a sectional view of the optional optical-haptic monitoring component according to a second variant (type C),

14: a perspective view of the hydraulic controller according to the invention according to FIG. 2 with the protective cap fitted,

Fig. 15: Detailed views of the protective cap and

16: a sectional view of the protective cap and of the hydraulic regulator with the protective cap fitted.

The hydraulic device according to the invention is to be presented below using a first exemplary embodiment with reference to FIGS. 2 to 5, which is a hydraulic controller with a load-sensing controller I and a pressure cut-off II, which are in a common housing 14 are located. This embodiment is explained on the assumption that the hydraulic controller is used to actuate the actuating device of a hydraulic pump. The hydraulic controller has four external connections 10, 11, 12, 13 for creating oil connections, namely the connection 10 for the high pressure outlet of the hydraulic pump to be controlled, the connection 11 for the tank return, a connection 12 for the actuating device of the hydraulic pump and a connection 13 for the supply of the external control pressure. The load-sensing controller I and the pressure cut-off II are connected to one another via a common bore 15, which is sealed to the outside.

Both controller axes, i.e. those of the load-sensing controller I and that of the pressure cut-off II are equipped with the following components from right to left in relation to the arrangements selected in FIG. 2. A closure system 16, which is oil-tight even at the maximum possible pressure level in the high-pressure bore 10a. A control piston 17, with two corresponding annular recesses in sections along its circumferential surface (not shown in FIG. 2), so that, depending on the longitudinal position of the control piston 17, the required oil connections are present both within the controller and to the external connections 10-13. A compression spring 18 with a support system 19 of the piston end. (The support system 19 can be designed, for example, as a spring plate and the compression spring 18, for example, as a helical spring. Alternatively, a compression spring support system can also be constructed by lining up plate springs.) [0052] An adjusting screw 20 for pretensioning the compression spring 18 with an extension serving as a spring plate. A closure system, which must be sealed up to the maximum possible oil pressure level in the spring chamber 18a. According to the invention, the closure is formed by the set screw 20, i.e. the adjusting and locking screw 20 is in one piece.

According to an advantageous embodiment, there is an advantageous limitation of the possible adjustment range of the minimum and maximum prestress of the compression spring 18 and thus an advantageous limitation of the possible adjustment range of the pressure cut-off for the connected hydraulic pump. In most applications of a hydraulic controller, the highest pressure levels at the high pressure outlet of the hydraulic pump can occur at the maximum possible preload of the compression spring 18. The maximum possible value of this pressure level is lower when the compression spring 18 is weakly preloaded. It is possible to use the controller, in which an inverse relationship between the prestress of the compression spring 18 and the pressure level present at the high-pressure outlet 10 of the hydraulic pump is possible, but is not considered further in the following text.

Stop for limiting the minimum pretension of the compression spring 18 in the spring chamber 18a of the load-sensing controller I, the screw connection between the controller housing 14 and the adjusting screw plug 20 against the maximum possible pressure level of the control pressure supplied via the connection 13, which can be around 10 bar in practice, be sealing. A support ring 23 is placed in the groove 21 in the adjusting screw plug 20, which is used as the sealing element O-ring 22 (cf. detailed view of FIG

CH 714 022 A1

Fig. 4). At a correspondingly high control pressure, the O-ring 22 is pressed against the support ring 23, as a result of which the load-sensing regulator I remains pressure-tight.

In the pressure cut-off II, the O-ring 22 can also be combined with a support ring 23 to maintain a common part strategy. Here, the sole use of an O-ring 22 on the adjusting screw plug 20 is sufficient for sealing, because there is always low pressure in the volume to be sealed in this way. Either there is an oil connection from this volume 18b to the tank return via the connection 12 or there is only a slight overpressure of approximately 1 to 2 bar in this volume 18b, namely when, due to the position of the control piston 17, hydraulic oil returns from the connection 12 of the control device (ie from the control cylinder) coming into the tank return.

A so-called demand flow control of the hydraulic pump is achieved by using a load-sensing controller I. Such a regulation, with the aim of saving energy, prevents the hydraulic pump from building up an unnecessarily high pressure level in the hydraulic oil circuit in those operating phases in which the hydraulic consumers require only low volume flows of hydraulic oil. From the point of view of energy efficiency, setting the lowest possible load-sensing pressure is advantageous. However, operation in the area of low pressures in which the control is not working reliably must be avoided (approx. Below 10 bar). This is why a load-sensing controller has an end stop position beyond which it is not possible to lower the load-sensing pressure further, the so-called pmin stop. In certain applications, such as winch drives, a certain pressure reserve must be available, which is why the load-sensing pressure value is set to a few tens of bar (up to 60 bar). So that the setting to an unnecessarily high value is avoided, the load-sensing controller I can also be equipped with a pmax stop. The setting of the load-sensing pressure is expediently adapted to the requirements of the hydraulic system and to those of the application.

The use of a pressure cut-off II for regulating a hydraulic pump limits the setting range for the maximum possible pressure level at its high-pressure outlet, which serves to avoid overloading the hydraulic system including the hydraulic pump itself. In contrast to a pressure relief valve, which discharges the excess power via a bypass and thus ultimately converts part of the hydraulic power provided by the hydraulic pump into the heating of hydraulic oil, pressure cut-off acts on the actuating device of the hydraulic pump in such a way that the so-called cut-off pressure does not can be exceeded. The need for a pmax stop for pressure cut-off is certainly self-explanatory. If the pressure level is too low, stable control is not possible. In addition, a cut-off pressure set at a very low pressure level would prevent the leakage required for lubrication. For the reasons mentioned, a pmin stop is also useful for a pressure cut-off.

In the embodiment of the mounted controller shown in FIG. 2, the narrow end of the adjusting screw 20 protrudes axially centrally into the helical spring 18. In its continuation, the locking screw 20 has a larger diameter. There is a particularly significant increase in its outside diameter at a certain length of the adjusting screw 20. There is a surface that is oriented perpendicular to the imaginary axis of the locking screw 20, on which it is supported on the compression spring 18 designed as a helical spring (cf. FIG. 2). This support surface can also be conical or curved (convex or concave). Instead of a helical spring 18, it is also possible to use a different spring element, for example a series of individual plate springs.

In an optional embodiment, the locking screw 20 is not supported directly on the compression spring 18, but via a washer inserted between them. In this case, a hardened washer is particularly preferred. Generally, a coil spring 18 will scrape on its bearing surface during use and could lead to material abrasion over its useful life. In any case, chip formation must be avoided since abraded material would get into the oil circuit and could lead to consequential damage. Therefore the contact surface has to be hardened. The execution of a fully or partially hardened locking screw 20 is of course much more expensive than the use of a hardened washer.

The longitudinal sections along which the adjusting screw plug 20 is located close to the inner surface of its receiving bore in the controller housing 14 are as follows: Adjacent to the groove 21 provided for accommodating the said sealing element, there is in each case a longitudinal section of the adjusting Locking screw 20, in which the outside diameter has almost the same dimension as the opposite inside diameter of the housing bore in the controller housing 14. There is an external thread 24 in the end region of the adjusting screw plug 20, where its largest diameter is present. The area of the housing bore in the regulator housing 14 opposite this has a matching internal thread, which extends from the radial groove 25 described later in the axial direction to a section enough, from which the diameter of the housing bore tapers steadily. In the embodiment according to FIGS. 2 to 5, the number of threads within the housing bore is greater than that of the adjusting screw plug 20, but this is not absolutely necessary. With regard to this threaded connection, such a coordination between the locking screw 20 and its housing bore in the regulator housing 14 is required, which enables the setting of different spring preloads, which include the setting range of the low preload of the compression spring.

CH 714 022 A1 In an advantageous embodiment, the locking screw 20 is located completely within the controller housing 14 over its entire adjustment range, and after the adjusting locking screw has been inserted into its installation position when the controller is assembled, a locking mechanism is provided, which prevents the locking screw 20 from being removed by turning it alone. In the shown and preferred embodiment, this can be done by a radial groove 25, which is machined into the wall of the housing bore of the controller housing 14 along the section of the housing bore that is outside the installation space of the adjusting screw plug 20. A shaft locking ring 26 (see FIG. 4) can be introduced into this radial groove 25. Clearly, the complete unscrewing of the locking screw 20 is only possible by removing the shaft locking ring 26 beforehand. Without removing the shaft locking ring 26, this forms a stop or an end position when the adjusting screw 20 is unscrewed.

Ideally, the radial groove 25 and thus the shaft locking ring 26 is located exactly at that position, so that when the end position is present, in which the head of the adjusting screw 20 abuts the shaft locking ring 26, the minimum permissible prestress of the compression spring 18 results. With this setting, the set cut-off pressure is at the still permissible minimum value. By configuring the position of the shaft locking ring 26 or its contact surface facing the interior of the controller housing 14, the distance along the adjusting screw 20 between the contact surface to the shaft locking ring 26 to the contact surface of the compression spring 18, the spring length of the relaxed compression spring 18, and its spring hardness, The disk thickness of the spring plate 19 and the piston-side end position of the spring plate 19 result in a minimum value for the prestressing of the compression spring 18.

In an advantageous embodiment, the two contact surfaces on which the compression spring 18 is supported are particularly wear-resistant, e.g. by hardening or coating the one-piece locking screw 20 or the spring plate 19 or both parts. In an alternative embodiment, a separate spring plate is provided instead of an extension on the one-piece adjusting screw 20. In a particularly advantageous embodiment, only the contact surfaces on which the compression spring 18 is supported are hardened or coated. In a particularly advantageous embodiment, the said more complex components are not hardened or coated, but the contact surfaces on which the compression spring 18 is supported are represented by hardened washers attached. In a particularly preferred embodiment, hardened washers in standard dimensions are involved.

If, based on a specific controller configuration, a change is to be made such that the lowest possible setting value of the minimum spring preload is to be raised and the setting value of the maximum possible spring preload remains unchanged, for example. an adjusting screw 20 with a longer screw head can be used or an adjusting screw at the head end of which there is an extension. Alternatively, the radial inner groove provided for receiving the shaft locking ring in the housing bore can be made to a greater depth, i.e. be brought closer to the spring chamber. With this objective, a washer or a stack of several washers with an adapted overall thickness is preferably inserted between the adjusting screw plug 20 and the shaft locking ring 26. No hardened washers are required at the installation location; a plastic version is also possible for this.

If, on the basis of a specific controller configuration, a change is to be made such that the lowest possible setting value of the minimum spring preload is to be lowered and the setting value of the maximum possible spring preload remains unchanged, the opposite steps can be carried out; a shortening of the screw head of the locking screw 20 if there are enough threads available for this, or a reduction in the length of the extension on the screw head. Alternatively, the radial inner groove provided for receiving the shaft locking ring in the housing bore can be introduced to a lesser depth. If a stack of at least one washer is present between the adjusting screw plug 20 and the shaft locking ring 26, its overall thickness can be reduced.

If, based on a specific controller configuration and without reworking the controller housing, a change in the bandwidth between the lowest possible and the highest possible adjustable spring preload is required, there are also various implementations. Since the shifting of this bandwidth to lower spring preloads is the opposite of measures to increasing this bandwidth, the explanations are limited to the latter. A stronger preload and a higher restoring force is achieved by using a longer spring with the same spring hardness. Alternatively, such a change would be possible by means of such a conversion, which leads to an end position of the spring plate 19 located at a short distance from the locking screw 20 (a piston 17, which, with regard to its hydraulic control function, continues into the spring chamber 18a with the same adjusting position is sufficient or the use of a spring plate 19 with a correspondingly thicker edge thickness, etc.). As a further alternative, an adjusting screw plug could be used, the length section of which has a larger dimension between the groove for receiving the sealing system 22, 23 and the contact surface of the compression spring 18.

Compared to these four possibilities to achieve a shift in the bandwidth between the lowest and the highest possible adjustable spring preload, washers are preferably used. The use of washers is possible, for example, between the control piston 17 and the spring plate 19, between the spring plate 19 and the compression spring 18, between the compression spring 18 and the locking screw 20.

CH 714 022 A1 It is particularly advantageous to use at least one washer in each case between the compression spring 18 and its support surface on the locking screw 20 or on the spring plate 19 or on the support surface of these two components. If washers are used in different slightly different thicknesses or several very thin washers, the desired adjustment of the range of the prestress of the compression spring 18 can be achieved. Since the surface of a washer, on which the compression spring 18 rests, should advantageously consist of a particularly hard material, it can be advantageous to harden one of the provided washers on one side. In order to achieve the distance actually required, a corresponding layer thickness can be removed from the unhardened side of the prepared washer or this washer can be used in a stack with at least one further washer, depending on whether the prepared washer is too thick or too thin. It is very particularly preferred to use a hardened washer of a standard size on each contact surface of the compression spring 18 and, if necessary, to use further required washers made of unhardened standard material.

In a hydraulic controller constructed as described in the preceding text, the locking screw 20 can be moved with the provided assembly tool within the adjustment range, whereas - by unconsciously turning the locking screw 20 in the direction of inadmissibly low spring preloads for the application is avoided ; as well as careless removal of the locking screw 20.

In order that the setting screw 20 can be mounted, the associated mounting thread in the controller housing 14 can extend to the outer end of the housing bore. A longitudinal section of the housing bore which is closely spaced on both sides from the installation location of the shaft locking ring 26 is advantageously made as a cylindrical counterbore, the diameter of which is slightly larger than the outside diameter of the thread 24. The latter facilitates the assembly of the shaft locking ring 26 and prevents the thread 24 from being deformed by the shaft locking ring 26. As an alternative to a thread extending up to the surface of the housing 14, the entire length section within the housing bore, starting from the housing surface and ending in the housing bore, can achieve the same advantages The length of the inner diameter protruding slightly beyond the installation location of the shaft locking ring 26 has a width which is slightly larger than the outer diameter of the thread 24 present for installing the locking screw 20.

For attaching an assembly tool for actuating the locking screw 20 (for installing or removing and adjusting the cutting pressure or the load-sensing pressure) there is a suitable recess for the tool starting from its end face (see, for example. Fig. 4). The structure of the locking screw 20 allows a variety of possible embodiments of such recesses. This can either be deliberately compatible with a standard tool (here: a hexagon socket) in a standard size or, for better protection against unauthorized tampering, in such a way that it can only be operated using a special tool that does not comply with a standard.

Stop for limiting the maximum pretension of the coil spring. The exemplary embodiment shown in FIGS. 2 to 5 has two adjustment ranges. With reference to the application example load sensing control, the load sensing pressure level can be set within a certain bandwidth, the lower adjustment range, from the absolute minimum value to a pressure level that is still typical for applications in which the lowest possible power loss is achieved absolute priority is given, whereas a load-sensing pressure level can be set in an adjustment range above it for particular applications for which it is necessary or advantageous to have a certain pressure reserve available.

With reference to the application example pressure cut-off, which is retained in the following text, the cut-off pressure can be set within a certain bandwidth, the lower adjustment range, from a minimum value assigned by the pmin stop to the upper limit of the pressure level at which the hydraulic system can be operated continuously , Within a bandwidth immediately above it, the cut-off pressure can be set within a temporarily permissible overpressure range up to an upper limit that can no longer be exceeded. When moving the locking screw 20, the fitter perceives whether its position would cause a pressure cut off below or within the regular work area.

To explain this novel regulator securing mechanism, the length section of the adjusting screw plug 20 mounted in the regulator housing 14 is considered, which is located in the vicinity of the O-ring 22. Essential features of this length section can be seen in FIG. 5, which shows a detailed view of the controller of FIGS. 2 to 4. Starting from a positioning of the locking screw 20 in the controller housing 14, in which the compression spring 18 has the minimum permissible or a slightly higher pretension, the length section x of the lateral surface of the adjusting locking screw 20 lying on the right side to the O-ring 23 is located on the opposite wall section 11 of the housing bore of the controller housing 14, where there is an inner diameter of size D1. Because of the comparatively large distance there, there is virtually no friction within this length section x when the adjusting screw plug 20 is screwed in further into the controller housing 14. A friction between the adjusting screw 20 and the controller housing 14 occurs at the threaded connection 24 and in the

CH 714 022 A1

Areas of the O-ring 22, the support ring 23, if any, and the washers, if any. A certain amount of friction is necessary, since otherwise the locking screw 20 could adjust itself before fixing the setting. In order to avoid the automatic adjustment - for example due to vibrations occurring during use - the locking screw 20 is fixed by a clamping screw 52, which is provided, for example, with a continuous threaded hole in the corresponding position of the controller housing 14 and on a cylindrical section of the Set screw 20 hits. When the clamping screw 52 is loosened, the locking screw 20 can be set within a certain range. Depending on the setting, the pressure level is determined, which can be present at the high-pressure outlet 10 of the hydraulic pump at a maximum if there is sufficient mechanical input power. As mentioned, this limitation that can be set on a hydraulic controller is referred to as pressure cutoff. The so-called cut-off pressure can be adjusted within a certain range.

In order to avoid damage, the range of the cut-off pressure should only be adjusted in the area in which the hydraulic pump or a hydraulic motor or a hydraulic system can be operated continuously. In order to avoid damage and prevent a hazard, the cut-off pressure must not be above a critical value.

The housing bore for receiving the adjusting screw 20 in the controller housing 14 has a length section 12 adjoining the length section 11. At the transition area of these two length sections 11, 12, the inside diameter changes from D1 to D2, the inside diameter D2 present in the length section 12 being slightly smaller than the diameter D1. Here, the inside diameter D1 is matched to the outside diameter Dx of the locking screw 20, which it has in the length section x, that with a locking screw 20 screwed in correspondingly far in, this leads to an overlap of the length section x of the locking screw 20 and the length section 12 of the housing bore in the controller housing 14, there is an interference fit in this overlap area.

If there is such an overlap and thus the interference fit, then a higher torque must be applied to screw the adjusting screw 20 in and out. Appropriate dimensioning of the diameters D1 and Dx and a corresponding quality of the surfaces concerned means that the locking screw 20 can be moved within this overlap area with a force that is still manageable, but is noticeably higher, that is to be applied to the assembly tool.

At the end of the length region 12 facing the compression spring 18, there is a clear tapering of the inside diameter of the housing bore of the regulator housing 14. The tapered area forms a stop against which the locking screw 20 finally abuts when it is screwed further into the controller housing 14 starting from the overlap area. Due to a correspondingly adapted bevel, as can be seen in FIG. 5, when this second and at the same time final / hard stop is reached, when the adjusting locking screw 20 and the housing bore in the controller housing 20 meet, there is an enlarged abutment surface 28, which increases the stability of the Attack is achieved. The risk is clearly counteracted that the edge of the locking screw 20 striking the stop gradually digs into the stop and the associated risks of material abrasion entering the oil circuit and an unwanted shifting of the final stop position become much less likely.

In a preferred embodiment, without contradicting the above features by the construction and function advantageous in order to achieve protection against negligent removal of the locking screw and a limitation of the minimum pressure level, the affected controller components are dimensioned such that the Adjustment screw 20 is located in the overlap region when the position defined there for a pressure cut-off takes place at an already particularly high pressure level, the presence of such a pressure level at the high-pressure outlet 10 of the hydraulic pump being less than a pressure when it is reached, the risk of which there is instantaneous damage or even immediate destruction of the hydraulic pump. Nevertheless, a longer lasting operation of the hydraulic pump with the particularly high pressure would shorten the service life. It follows from the features described above that, in this preferred embodiment, the bevelled abutment surfaces 28 of the locking screw 20 and the housing bore of the regulator housing 14 should meet one another while maintaining the previous features, in which there is a pretension of the compression spring 18 which leads to a pressure cut-off, which is in any case below a critical value which, if exceeded, would result in excessive damage to the hydraulic pump.

In the following, in addition to the above-described one-piece adjusting screw 20 according to the invention, three extensions based thereon (a variant 2, a variant 3 and a variant 4) will be presented.

The housing 14 of a hydraulic regulator equipped with an adjusting screw 20 according to the first embodiment (cf. FIGS. 1 to 5) must have a certain additional length (in relation to the drawing orientation) on the left-hand side to accommodate the shaft locking ring 26. This fundamental disadvantage can be avoided by using an adjusting screw 20 of variant 2, 3 or 4. How these variants work

CH 714 022 A1 are successively explained on the basis of their respective installation process in the controller housing 14, from which the design features of the variants are also shown.

Installation of a set screw 20 'of variant 2:

In the phase of installation shown in FIG. 6, a few threads 24 'located on the head of the adjusting screw plug 20' already engage in the internal thread 24a 'of the controller housing 14'. (To the right of the head, the lateral surface of the adjusting screw plug 20 'has many different, respectively rotationally symmetrical sections in the axial direction.) Near the right end of the adjusting screw plug 20' there is a radial groove 25 'with an attached shaft locking ring 26'.

In the installation situation shown in FIG. 7a, the adjusting screw plug 20 'is screwed a little further into the controller housing 14' and is located exactly at the position at which the shaft locking ring 26 ', which has not yet been compressed, on the narrowing wall section 29 'of the housing bore for receiving the locking screw 20'. By continuing the screwing-in process, the shaft locking ring 26 'is guided along the contour of the narrowing wall section 29' and is always pressed further together until the area of this radial groove 25 'of the locking screw 20' penetrates into the spring chamber 18a '. The internal diameter there is correspondingly large, so that the shaft locking ring 26 'relaxes at a certain depth of penetration.

Based on the installation situation shown in FIG. 7b, it can be seen that the locking screw 20 'can no longer be dismantled, but the relaxed shaft locking ring 26', which is still locked in its radial groove 25 ', on a flat wall area inside the spring chamber 18a 'strikes, whereby there is an end stop. Consequently, using such an adjusting screw plug, there is a defined minimum value for the prestressing of the compression spring 18 '. In the embodiment shown here, there is no clearly defined upper limit for the prestressing of the compression spring 18 'and therefore no upper limit for the pressure cut-off, due to the shaft locking ring 26' located in the spring chamber 18a '. With regard to the entire hydraulic device according to the invention, such a limitation can be achieved by using exactly those principles for an adjusting screw plug 20 'of variant 2 and the housing bore for this purpose in the controller housing 14' analogous to the configuration for using an adjusting screw 20 of the variant 1 are adopted.

By a small modification of the housing bore in the controller housing 14 for receiving the locking screw 20 'of variant 2, the stop can be implemented differently to achieve the maximum prescribable upper pressure cutoff. In this implementation, referred to as variant 3, according to FIG. 8, within the housing bore of the controller housing 14 between the spring chamber 18a and the narrowing, preferably conically narrowing section 31 there is a region which can be appropriately referred to as the annular chamber 30. The annular chamber 30 has an enlarged cross section. When the associated adjusting screw 20 of variant 3 is installed, the shaft locking ring 26 placed in the radial groove 25 is pushed over the conical section 31 of the housing bore until the corresponding screw-in depth is reached until it dips into the annular chamber 30 and expands there to its original dimension. but still remains locked in the radial groove 25. From the perspective of the shaft locking ring 26, there is an abrupt narrowing and thus an insurmountable position in the transition area between the ring chamber 30 and the spring chamber 18a; equally as at the transition region between the annular chamber 30 and the conical section 31 of the housing bore. Clearly, the adjusting screw 20 can only be moved within the bandwidth corresponding to the axial extent of the annular chamber 30.

In a variant 4 of the adjusting screw 20 'according to FIG. 9, the section provided on its head with the external thread 24' is interrupted by a radial groove 25 '. Also in the housing bore of the controller housing 14 ', the section equipped with the internal thread is interrupted over a certain length by a radial groove 32' made there, which has at least a larger to a much larger length dimension than its depth dimension. In the housing bore in the controller housing 14 'there is consequently a widening of the cross-sectional area Ax over this length section.

To mount such a set screw 20 'of variant 3, the controller housing 14' must be positioned such that the set screw 20 'can be inserted vertically from above. A shaft locking ring 26 'is then introduced by pressing it into the area of the housing bore widened by the radial groove 32'. There, the shaft locking ring 26 'is relaxed so that it comes to lie flat in the end area of the radial groove 32' facing the spring chamber 18a ', where the cross section is narrowed accordingly. Subsequently, the adjusting screw plug 20 'is inserted into the housing bore and screwed into the controller housing 14'. The intended design provides that the wire diameter of the shaft locking ring 26 'has at most the dimension of the flank width of the thread 24' so that the shaft locking ring 26 'already inserted in the controller housing 14' and blocked by the end region of the radial groove 32 'facing the spring chamber 18a' Screwing in the locking screw 20 'slides over its threads 24'. As soon as the adjusting screw plug 20 'is screwed in so far that its radial groove 25' reaches the shaft locking ring 26 ', it snaps into place. From this assembly description it is clear that the diameter of the cross-sectional area Ax must be slightly larger than that resulting during the assembly step

CH 714 022 A1

Diameter of the shaft locking ring 26 'when sliding over the thread 24' of the locking screw 20 'to take its end position, namely in the radial groove 25' of the locking screw 20 '.

Fig. 9 shows such a set screw 20 'with a shaft lock ring 26' in the end position described. As can clearly be seen, there is a fixed end stop in each direction of adjustment and thus a limited range of adjustable prestressing of the compression spring that is defined on both sides. The shape of the contour at the two ends of the groove 32 'of its length extension is of considerable importance. If the locking screw 20 'reaches the vicinity of one of its end positions or one of its end positions, then that part of the groove 32' in the housing bore which contacts the shaft locking ring 26 'exerts a force on the shaft locking ring 26'. For the following reasoning it is useful to split this force into two components. A radial force component related to the regulator axis presses the shaft locking ring 26 'exactly in the center into the radial groove 25' provided at the head of the adjusting screw plug 20 '. The other axial force component related to the regulator axis exerts a force on the shaft locking ring 26 ', which tends to push the shaft locking ring 26' out of the radial groove 25 'present in the head of the adjusting screw plug 20', i.e. at least there is a tendency to destroy the end stop.

An angular shape of the said contour would be particularly unfavorable, because then when the end position is reached there is only a force which tends to push the shaft locking ring 26 'out of the radial groove 25' provided in the locking screw 20 'and the other direction of force, by which the shaft locking ring 26 'is not pressed into this radial groove 25' at all. So that such a desired direction of force is present, there must be a corresponding non-abrupt taper in this contour. A contour which is convex or conical with respect to the controller axis is, however, unfavorable, since the shaft locking ring 26 'tends to tilt when the adjusting screw 20' is screwed into one of its end positions. Accordingly, a concave contour is usefully used. In a preferred embodiment, the contour positively closes with that surface of the shaft locking ring 26 'which it assumes when it is pressed into the radial groove 25' of the locking screw 20 '. In a particularly preferred embodiment, this contour is slightly larger than such a form-fitting contour, so that when a final stroke is reached, the said desired directional component of the force is comparatively large and, on the other hand, tilting is avoided.

So that the turning of the locking screw 20 'over the entire intended adjustment range and thus the thread 24' of the locking screw 20 'and that existing in the controller housing 14' is possible over the entire toothed area, must pass over the groove area 32 ' clearly the same continuations of the threads are present that would exist if these radial grooves 32 ', 25' were not present.

The latter relationships obviously also apply to the end stop position of the shaft locking ring 26 'in the spring chamber 18a in variant 2 and also to the two end stop positions of the shaft locking ring 26 in the ring chamber 30 in variant 3.

Application to hydraulic valves The hydraulic device according to the invention can also be applied to hydraulic valves. An adjustable pressure relief valve can be used as one of many application examples. The possible setting range can be limited with the same implementations as in the design variants shown with the pmin and pmax stops. Likewise, the creation of two different setting ranges, which is also advantageous in certain applications for a pressure relief valve and other hydraulic valves, can be implemented.

Optical-haptic monitoring of the set preload of the compression spring For the above-described statements for setting the compression spring acting axially displaceably in the housing bore of a hydraulic device, it is desirable to provide an optical-haptic monitoring option for the set spring preload. Haptic monitoring is a great advantage because in certain installation situations during such maintenance work to be carried out on site, the micrometer cannot be recognized, but can be felt, for example when using hydraulic components in mobile machines. In the following, such an assembly for optical-haptic monitoring is presented in three different expansion stages - referred to as types A, B and C. All of the types presented can be combined with the known exemplary embodiments of FIGS. 2 to 9. In addition, the assembly described below for optical-haptic setting monitoring can generally be used for setting hydraulic regulators and hydraulic valves. The explanation of the structure and the mode of operation takes place using the example of setting a pressure cut-off.

Module for the optical-haptic monitoring of the set pressure cut-off according to type A. The exemplary embodiment is based on the embodiment variant of FIGS. 6 and 7, but shows modifications to the adjusting screw plug 20. FIG. 10 shows a partial view of the hydraulic controller longitudinal section in the close range the one-piece adjusting screw 20. Its right end protrudes into the spring chamber 18a associated with the regulator axis. On

CH 714 022 A1 on the left-hand side, the head end of the locking screw 20, there is a threaded connection 24 between it and the controller housing 14.

In contrast to the embodiments considered so far, the adjusting screw 20 considered here has a functionally tapering, preferably conical surface area 34 within a comparatively extensive specific length section. In the controller housing 14 there is a further bore 35 which crosses the housing bore serving to receive the adjusting screw plug 20. A measuring screw 33 is fastened in this bore 35 provided with a thread 37. This is a nut screw 36, which in turn comprises a pin 38 and a chamber 39a equipped with a compression spring 39 along a continuous axial recess. Depending on the screw-in depth of the locking screw 20, the defined pitch of its conical shape 34 results in a position of the pin 38 guided in its nut screw 36 and resting on the cone 34 and pressed there by the compression spring 39 or the lower tip of the pin 38.

With regard to the mass in question, the components under consideration can be designed such that the intended setpoint value for the pressure cut-off is present precisely at the screw-in depth of the locking screw 20 at which the upper end face of the pin 38 is flush with the top of the nut screw 36. If different pressure cut-offs have to be set for different copies of a hydraulic controller or the pressure cut-off of a hydraulic controller should be set to a different value, a correspondingly differently dimensioned measuring screw with the same basic structure can be used.

[0098] The following apply to all of the illustrated module embodiments of the optical-haptic monitoring of the set pressure cut-off:

It should be pointed out that the figures in FIGS. 10 to 13 are always simplified representations from which the functionalities can be seen which, on the one hand, compared to the prior art and, on the other hand, to the inventive ones in the preceding Delimit text already presented system solutions. Such details, which are necessary for an implementation but are not to be regarded as inventive, are not shown in the foils to such a depth as is required by a production drawing. For example, in a real implementation of the portion of the hydraulic device shown in FIG. 10 between the housing 14 and the locking screw 20, an oil seal is provided in the transition region of the spring chamber 18a associated with the regulator axis and the section of the housing bore in the housing 14 in which the conical region 34 of the locking screw 20 is required.

The mechanism shown in Fig. 10, i.e. the equipment of a hydraulic regulator or a hydraulic valve with a type A assembly can be used in combination with any of the hydraulic devices according to FIGS. 2 to 9 already presented, by setting a pressure cut-off II, setting a load-sensing regulator I or the setting of an opening pressure of a pressure relief valve etc. is simplified.

Furthermore, these combination options apply to the expansion stages of types B and C explained below.

In the representation in the form of a technical drawing, all three different stages of expansion, types A, B and C, of the module for the optical-haptic monitoring of the set pressure cut-off have the (almost) the same external view shown in FIG. 11. Due to the presence of a compression spring 39 in the spring chamber 39a inside the nut screw 36, the upper end of the pin is located inside the nut screw 36 and does not protrude from the head of the nut screw 36 in the case of a removed micrometer 33 belonging to the modules according to expansion stages A and B. as can be seen in the right representation of FIG. 11.

Module for the optical-haptic monitoring of the set pressure cut-off according to type B. The micrometer 33 belonging to such a type B according to FIG. 12 consists of a nut screw 36 in whose axial recess an adjusting pin 38b and a viewing pin 38a are accommodated. In this recess there is a sealed volume 40 filled with fluid between these two pins. The shape of the sight pin 38a and the length section of the nut screw 36 that accommodates it provides a free space with an installed compression spring 39 which presses the sight pin 38a in the direction of the setting pin 38b. If the assembly shown here is properly installed in a hydraulic device, the setting pin 38b exerts pressure on the enclosed fluid in the volume 40. According to the present cross-sectional areas A1 and A2, a movement of the setting pin 38b by a length 12 causes a movement of the length 11 = I2 * A2JM in the sighting pin.

A correspondingly selected area ratio of A1 and A2 results in an already small movement of the adjusting pin 38b - i.e. a slight adjustment of the locking screw 20 - a large movement of the viewing pin 38a. Consequently, when using such a type B assembly, a significantly more precise setting of the pressure cutoff or. achieve the preload of the compression spring.

Module for optical-haptic monitoring of the set pressure cut-off according to type C. In its basic structure and its basic function, a type C module corresponds to a type B, but as an extension has a snap-in function, by means of which it is recognized whether the cut-off pressure of the regulator or the valve has been set above the permissible maximum value. This extension is shown in Fig. 13. The sight pen

CH 714 022 A1

38a can be inserted with the shaft locking ring 42 fully pressed into its radial groove 41 into the bore of the nut screw 36 and axially moved therein within a certain range.

The nut screw 36 used in type C also has a radial groove 43 adapted to said shaft locking ring 42 within its axial bore. If the adjusting pin 38b and thus also the sighting pin 38a are moved so far in the direction of the upper head end of the nut screw 36, the shaft locking ring 42 placed on the sighting pin 38a reaches the radial groove 43 located in the nut screw 36. This in turn leads to the intended execution of the two radial grooves 41, 43 and that of the shaft locking ring 42 (and that of the compression spring 39) so that the shaft locking ring 42 engages in the radial groove 43 of the nut screw 36 and at the same time remains locked in the radial groove 41 of the viewing pin 38a. As a result, the positions of the two pins 38a, 38b within the nut screw 36 are preserved.

By in turn designing the components involved in the snap-in function as intended, it can be achieved that this irreversible snap-in takes place when the setting of the pressure cut-off has exceeded an impermissibly high limit value, i.e. mathematically and therefore more precisely put into words, has adopted an impermissibly high limit. So that it can be ruled out that the micrometer has not been removed and the pressure cut-off has reached an impermissibly high limit value, precautions must be taken to avoid dismantling the micrometer or a measure must be taken that can be removed afterwards. An advantageous precaution is a threaded connection 37 made with a predetermined breaking point between the controller housing 14 and the micrometer 33. The use of a type C module clearly offers itself in arrangements in which exceeding a maximum pressure is particularly critical.

Protective cap / double protective cap In one expansion stage, a protective cap can be used both for a hydraulic controller corresponding to the prior art and for a hydraulic controller according to the invention; equally for a state-of-the-art hydraulic valve or a hydraulic valve according to the invention. The use of a component designated as a protective cap and, in the case of a two-stage controller, as a double protective cap 50 and explained in more detail in the following text, is proposed in particular for the hydraulic controllers embodied in the preferred variant. An embodiment of the double protective cap 50 is shown in FIGS. 14-16. 14 shows the controller housing 14 with the double protective cap fitted, and FIG. 15 shows the top and bottom of the double protective cap 50 in two illustrations. FIG. 16 shows a sectional view of the protective cap 50 and the controller housing 14 with the double protective cap 50 mounted.

In production, the double protective cap 50 can be put on as soon as the shaft retaining rings 26 have been installed. The controller remains fully functional even without being equipped with a double protective cap 50. By means of a double protective cap 50, the area of the housing bore in the controller housing 14 outside the adjusting screw plug 20 can be covered with the threads 24 present there, the built-in shaft locking rings 26 and the recesses on the head side of the adjusting screw plug 20, to which the assembly tool must be attached to protect it from damage and from the ingress of dust and other dirt.

The double protective cap 50 is equipped with corresponding claws 51 which, when placed in the correct position, snap into complementary recesses on the controller housing 14 by being lightly pressed on. In addition, recesses 53 can be provided on the cap 50 or the claws 51 in order to increase the flexibility of the cap 50 and to simplify the assembly. Suitable materials for the production of the double protective caps 50 are a plastic which is suitable for the operating conditions, e.g. PVC on. In an advantageous embodiment, the removal of a double protective cap inevitably leads to its intended destruction. Availability of such double protective caps 50 in different colors is particularly advantageous. It is then possible to equip the controllers with a double protective cap 50 of color a during factory assembly. If work on the controller has been carried out by employees or specially certified service technicians from other companies, double protective caps 50 in a color b can be used. In order not to deter potential customers by a service commitment, double protective caps 50 in a color c could be freely available so that corresponding hydraulic regulators can be equipped with one after work on the regulator has been carried out by third parties. (The latter and the further ideas merely describe the example of a possible constellation.) In the case of particularly high security requirements, the double protective caps 50 of the colors a and b can be identified with a unique number. The relevant employee of the service network could then make a note of the work previously carried out before each application of a new double protective cap 50, which is then clearly identifiable, to the controller known by its own ID number. A centralized service record can then be stored - as long as it is only carried out within a factory assembly and carried out by certified service technicians. In order to prevent an undetected forgery of the double protective caps 50, these can be clearly marked with a so-called tracer.

In an alternative embodiment of the invention, the hydraulic device is equipped with a plug instead of an adjusting screw. This embodiment is not shown in any of the illustrations, however

CH 714 022 A1, the only design differences from the exemplary embodiments in FIGS. 2 to 9 and 14-16 can be summarized briefly.

If a hydraulic device according to the described exemplary embodiment according to variant 1 is used with the sealing plug in the hydraulic controller, the longitudinal section of which is shown in FIG. 2 using the one-piece locking screw 20, the result is a very similar-looking arrangement. The differences amount to three details. As mentioned, the end of the sealing plug would rest against the shaft locking ring 25. In addition, the representation of said threaded connection 24 would be omitted in accordance with the convention of technical drawings. Furthermore, the cutout exposed in section for attaching a screwing tool would not be present, or such a cutout would be unnecessary.

In variant 2 of the hydraulic device described above, the sealing plug can have an outer radial groove within its outer surface, into which a shaft locking ring is placed before assembly. The variant 2 of the hydraulic device using a sealing plug has a certain analogy to the construction of the hydraulic device shown in FIGS. 6 and 7 or can have such an analogy, although an adjusting screw plug 20 is used in the latter construction. 8 how the contour of the housing bore for a hydraulic device of variant 3 can be designed. According to variant 3 of the hydraulic device with sealing plug described above, an outer radial groove can be provided near the end facing the spring chamber within the outer surface of the sealing plug, into which a shaft locking ring is placed before assembly. The dimensions of the outer radial groove and those of the shaft locking ring are designed so that the sealing plug can be pushed into the housing bore when the shaft locking ring is fitted and pressed together as intended. Variant 3 of the hydraulic device using a sealing plug has a certain analogy with the variant of the hydraulic device shown in FIG. 9 or can have such an analogy. It can be seen from FIG. 9 how the contour of the housing bore can be designed for a hydraulic device of variant 3.

[0116] The advantages of the invention and of the advantageous embodiments can be summarized as follows. While the adjusting screw 20, 20 ', 20, 20' according to the invention is in one piece - various embodiments are shown in FIGS. 2 to 9 -, the same applies to the low-cost variant of the hydraulic system according to the invention, in which a sealing plug for Is used, the subsystem fulfilling the corresponding functions according to the prior art consists of a set screw guide sleeve 5 built into the device housing and the actual set screw 8 (cf. FIG. 1). The cost of manufacturing each of these two components 5, 6 is roughly comparable to that of the one-piece adjusting screw 20, 20 ', 20, 20' according to the invention. In addition, both the set screw guide sleeve 5 and the set screw 6 each require an oil seal. Nevertheless, the design of the hydraulic device according to the invention prevents the negligent, unconscious complete unscrewing of the locking screw 20, 20 ', 20, 20'.

An inadvertent, unintentional setting of a hydraulic controller or hydraulic valve according to the invention, as a result of which the hydraulic machine or the hydraulic system operates in an outside of the permissible pressure range, which in turn leads to secondary damage - for example damage to the hydraulic machine, other hydraulic components or the destruction of components and also a shooting out of the closure device in the event of a thread tearing - is prevented. The latter clearly represents an accident prevention measure.

Also, in a device according to the invention, the presetting of the compression spring, which is defined according to the requirement, can be carried out much faster and more precisely because the locking screw is tightened and fixed in the radial direction and therefore has no influence on the previously set axial position the locking screw. On the other hand, locking a set screw 6 corresponding to the prior art causes the set value to be falsified, which in the case of corresponding applications leads to already comparatively large deviations in the operation of the hydraulic system. Such an application that is sensitive to this is, for example, the demand flow control, in which a small falsification in the specification of the load-sensing pressure already results in a clear undesired reaction.

Instead of a simple stop with which a single absolute maximum value of the adjustable preload of a compression spring is defined, there is a temporarily permissible overload range based on the application example of pressure cut-off, which is limited by a final maximum value. While a technician / service technician sets the pressure cut-off on the controller, you can feel directly whether this adjustment takes place within the specified operating range or already within the temporarily permissible overload range.

Protection against damage and against the ingress of dust and other contamination is made possible by the double protective cap 50. The different colors of the double protective caps make it easier to understand whether the pressure cut-off on a hydraulic controller has been set differently after delivery, or the preload of a compression spring of the hydraulic arrangement. Depending on the accepted effort in different levels up to a clear complete service record.

CH 714 022 A1 An optical-haptic monitoring of the set pretension of a compression spring in a hydraulic device offers improved and safe handling, for example in the application for setting a pressure cut-off. A slight adjustment of the locking screw 20, 20 ', 20, 20' as well as an additional hole in the hydraulic device in the controller housing 14, 14 ', 14, 14' and the addition of a micrometer 33 enable the exact by an optical-haptic control Set the pressure cutoff to a specific value. If the pressure cut-off of a regulator of the same type is to be set to a different, but in turn also firmly defined, value, a micrometer 33 can be provided for this, which differs only very slightly from the other micrometer, meanwhile no changes are required on all other components of the regulator.

With an expanded embodiment of the micrometer 33, the desired value of the pressure cut-off on the object, the controller, can be set more precisely. In a further expansion, this micrometer 33 can be designed such that the setting of the pressure cut-off to an excessively high value or remains visible at an impermissibly high value.

Claims (21)

claims 1.Hydraulic device, in particular hydraulic valve or hydraulic controller, with a housing, at least one piston axially displaceably mounted in a housing bore and in each case at least one compression spring acting on the at least one piston, at least one externally accessible adjusting screw inside the housing bore for adjusting the preload of the at least one compression spring is adjustable in the axial direction, characterized in that the at least one set screw engages directly with an internal thread of the housing bore and at the same time forms a closure system for sealing the spring chamber containing at least one compression spring to the outside. 2. Hydraulic device, in particular hydraulic valve or hydraulic controller, with a housing, at least one piston axially displaceably mounted in a housing bore and in each case at least one compression spring acting on the piston, characterized in that at least one sealing plug inserted directly into the housing bore is provided, the position of which influences the pretension of at least one compression spring and, at the same time, forms a closure system for sealing the spring chamber containing at least one compression spring to the outside. 3. Hydraulic device according to claim 1 or 2, characterized in that the adjusting screw or the sealing plug comprises at least one radial groove, into which a sealing element, in particular an O-ring, is introduced. 4. Hydraulic device according to claim 3, characterized in that in addition to the sealing element in the radial groove, a support ring is introduced, against which the sealing element can be pressed at a corresponding pressure level within the spring chamber. 5. Hydraulic device according to one of the preceding claims, characterized in that at least one screw is present by means of which the adjusting screw plug or the sealing plug can be clamped against the housing of the hydraulic device after being adjusted to the desired position and can thereby be fixed. 6. Hydraulic device according to one of the preceding claims, characterized in that the adjustment path of the adjusting screw or the position of the sealing plug is limited by means of at least one securing element, preferably a shaft locking ring, preferably in order to limit the minimum prestress of the compression spring and / or a to prevent the set screw from being completely unscrewed or the plug from being removed and / or to ensure that the set screw or the plug is sufficiently sealed. 7. Hydraulic device according to claim 6, characterized in that the shaft locking ring is introduced into an internal radial groove of the housing bore, preferably in the area of the internal thread of the housing bore for screwing the set screw. 8. Hydraulic device according to claim 6, characterized in that the shaft locking ring is introduced into an outer radial groove of the lateral surface of the set screw or of the sealing plug. 9. Hydraulic device according to claim 8, characterized in that the shaft locking ring introduced into the outer radial groove lies within the spring chamber and the minimum preload of the compression spring is defined by the stop of the shaft locking ring on a wall of the spring chamber. 10. Hydraulic device according to claim 8, characterized in that the shaft locking ring introduced into the outer radial groove lies within an annular recess of the housing bore dedicated for the shaft locking ring holder, and preferably the minimum and maximum preload of the compression spring is determined by the axial width of the ring-shaped recess, wherein the recess lies in the region of the end of the set screw or the closure plug facing the spring chamber or in the region of the end of the set screw or the closure plug facing the bore opening. CH 714 022 A1 11. Hydraulic device according to one of the preceding claims 1 and 3 to 10, characterized in that a limitation of the maximum screw-in depth of the set screw and consequently a limitation of the maximum adjustable preload of the compression spring is defined by a tapering diameter of the housing bore, preferably tapered the diameter of the inner bore running in the direction of the spring chamber is conical, particularly preferably with the same conicity as a counter-abutment surface of the adjusting screw. 12. Hydraulic device according to one of the preceding claims 1 and 3 to 11, characterized in that the adjustment path of the adjusting screw is divided into at least two adjustment ranges, the torque to be used for adjusting the adjustment screw being higher in one of the ranges, preferably the first Adjustment range is defined by the axial movement of a sliding surface of the set screw along a first length section of the housing bore and a second adjustment range is defined by the axial movement of the sliding surface along a second length section. 13. Hydraulic device according to claim 12, characterized in that the sliding surface in the first adjustment area slides almost smoothly along the first length section and in the second adjustment area there is an interference fit between the sliding surface of the set screw and the second length section of the inner bore. 14. Hydraulic device according to one of the preceding claims 6 to 10, characterized in that one or more washers are inserted or can be inserted into the housing bore between the shaft locking ring and the sealing plug in order to influence the pretension of the compression spring. 15. Hydraulic device according to one of the preceding claims 6 to 10, characterized in that one or more washers are inserted or can be inserted into the housing bore between the shaft locking ring and the adjusting screw in order to influence the minimum value of the adjustable preload of the compression spring. 16. Hydraulic device according to one of claims 6 to 10 and 14, characterized in that at least between one of the stop surfaces of the compression spring and the compression spring, one or more washers are introduced or can be inserted in order to prevent wear of the stop surfaces by the overlying compression spring and to influence the prestress of the compression spring that can be adjusted by the sealing plug. 17. Hydraulic device according to one of claims 6 to 10 and 15, characterized in that at least between one of the stop surfaces of the compression spring and the compression spring, one or more washers are inserted or can be inserted in order to prevent wear of the stop surfaces by the overlying compression spring and to change the range of the prestresses of the compression spring that can be set by the adjusting screw. 18. Hydraulic device according to one of the preceding claims, characterized in that at least one protective cap is provided which can be fixed on the housing for covering the at least one adjusting screw plug or the sealing plug, in particular by means of one or more claws which are pronounced on the protective cap and which in engage complementary recesses of the housing, the protective cap not being detachable from the housing without being destroyed. 19. Hydraulic device according to one of the preceding claims, characterized in that the device is a hydraulic valve with one or more valve elements, at least one of these valve elements comprising the adjusting screw according to the invention or the sealing plug according to the invention. 20. Hydraulic device according to one of the preceding claims 1 to 18, characterized in that the device is a hydraulic controller with one or more controller axes, at least one controller axis comprising the adjusting screw according to the invention or the sealing plug according to the invention. 21. Hydraulic device according to one of the preceding claims 1 and 3 to 20, characterized in that the adjusting screw comprises a tapering, preferably conical jacket section, to which a pin perpendicularly displaceable to the axial direction of the adjusting screw is adjacent, the position of which is an optical-haptic indicator for the pretension set by means of the adjusting screw is the at least one compression spring acting directly on the piston. CH 714 022 A1