DE102022118308A1 - PRESSURE REGULATOR VALVE - Google Patents

Abstract

Pressure control valve for a hydraulic line, which has a valve housing with a cylindrical wall area. The valve housing defines a longitudinal axis, with a base part closing the valve housing at one end. The pressure control valve further comprises a valve body group with a conical hollow valve cone which engages a plunger head. The valve cone is loaded by a first spring so that it seals with an inner sealing surface against the sealing contour of a sleeve. A contact surface on the tappet head provides a guide to contact surfaces on spokes inside the valve cone, so that the valve cone can be pivoted about axes perpendicular to the longitudinal axis.

Description

The invention relates to pressure regulating valves for hydraulic lines. The invention further relates to valve devices which have such a pressure control valve, to hydraulic circuits with such valve devices and to hydraulic axial or radial piston units with valve devices.

Valve devices are an essential part of many hydraulic axial or radial piston units. A special area of application is high-pressure valves, which are arranged in high-pressure lines of hydraulic units to drain hydraulic fluid when the pressure in the line rises above a predefined limit. On the other hand, for the successful operation of hydraulic units, it is important that the pressure in the low-pressure line does not fall below a certain limit. For this purpose, a valve with a feed function can be arranged in the low-pressure line, which opens a feed/loading connection to a hydraulic fluid container in order to supply hydraulic fluid to the low-pressure line. Depending on the operating conditions, e.g. the direction of rotation of a hydrostatic unit, the direction of travel of a vehicle or its type of drive, the pressure in the pressure lines of a hydraulic unit can change from high pressure to low pressure and vice versa. Therefore, it is desirable that valves arranged in the hydraulic lines fulfill both the pressure relief function and the feed function.

These valve devices can therefore be viewed as a high-pressure relief valve with a feed function. In known valve devices that can fulfill this function, the flow cross section is restricted for design reasons. However, a quick response is absolutely necessary, especially for the pressure-limiting function, for which relatively large flow cross sections are desired. For thermal reasons, the flow cross section should be restricted as little as possible so as not to overheat the hydraulic fluid. In order to meet these requirements, the valve devices known in the art would have to be designed with very large cross sections. However, this is not possible when installing in axial piston machines or for dimensioning reasons.

In addition, the known designs are prone to malfunctions due to manufacturing tolerances and inaccuracies. Therefore, the components of the valve devices as well as the parts of the hydraulic units into which the valve devices are installed must be manufactured with high precision. This not only increases the cost of producing the valve devices and the hydraulic lines into which the high pressure relief valves are installed, but also the cost of replacement in the event of component failure.

It is therefore an aim of the present invention to provide a valve device of the type mentioned which enables large flow rates with low pressure losses, requires little installation space, is tolerant of manufacturing tolerances and inaccuracies, has short response times and works reliably under high and low pressure conditions can be produced inexpensively.

This task is solved by a pressure control valve according to claim 1. Preferred embodiments are disclosed in the dependent claims. The object is further solved by a valve device according to claim 12 and in preferred embodiments according to the subclaims dependent thereon. The object is further solved by a hydraulic circuit according to claim 15 and by a hydraulic axial or radial piston unit according to claim 16.

According to the invention, a pressure control valve is provided for a hydraulic line. The pressure control valve includes a valve housing with a cylindrical wall portion that defines a longitudinal axis that represents the central axis of the cylindrical wall. A closing part closes the valve housing at one end. The pressure control valve further has a valve body group which has a hollow cylindrical sleeve which is movably arranged coaxially in the valve housing. The sleeve is slidably guided by the cylindrical wall section of the valve housing - at least by parts of the cylindrical wall area - and can slide relative to the valve housing in the direction of the longitudinal axis. The central/rotational axis of the sleeve is essentially identical to the longitudinal axis of the valve housing.

The outer peripheral surface of a longitudinal inner end region of the sleeve seals with the inner peripheral surface of the valve housing and thus forms a pressure chamber with the base region. The pressure chamber extends from the bottom area of the valve housing to the inside of the sleeve. At a longitudinally outer end portion of the sleeve, which protrudes from the valve housing, there is an outwardly directed sleeve seal contour and a radially inwardly directed spring seat. The spring seat on the longitudinally outer end section can be designed, for example, as a shoulder which extends radially inwards with respect to the longitudinal axis.

A valve tappet is arranged coaxially in the sleeve, ie the axis of the valve tappet is identical to the central axis of the sleeve and the valve housing. The valve tappet protrudes with a first end, which has a tappet head, from the longitudinally outer end section of the sleeve. A convex contact surface towards the sleeve is formed on the plunger head. If the longitudinally outer end of the sleeve is provided with an inwardly projecting shoulder, as described above, then the shoulder preferably has a central through hole through which the valve tappet stem can be guided.

A first spring is coaxially disposed inside the sleeve and around the plunger shaft. The spring is attached at one end to a spring seat which is arranged at the free end of the plunger shaft opposite the plunger head. At its other end, the spring is supported on the spring seat on the longitudinal outer part of the sleeve. In this arrangement, the first spring is able to bias the valve lifter towards the inside of the sleeve, i.e. in the assembled state towards the pressure chamber. According to the “actio = reactio” principle, the preload force acts on the spring seat on the sleeve and pushes the sleeve towards the plunger head.

The valve body group also has a hollow, essentially conical valve cone, which has an inner sealing surface in the area of the larger diameter for sealing with the sleeve seal contour. The valve cone also has an outer sealing surface in the lower diameter region which extends around an inlet opening of the valve cone in order to seal with a valve seat of a hydraulic line. A plurality of radially inwardly directed spokes extend into the interior of the hollow valve cone. At least some of the spokes have concave bearing surfaces facing the inlet opening.

The tappet head touches the concave contact surfaces of the valve plug with the spokes of the valve cone, i.e. with the convex contact surfaces of the tappet head. As a result, the preload force of the first spring is transmitted to the valve cone via the tappet head in order to press the valve cone against the outer sealing contour of the sleeve through the first spring. At the same time, the contact surface on the tappet head ensures guidance of the bearing surfaces on the spokes, so that the valve cone can be pivoted about axes perpendicular to the longitudinal axis and rotated about the longitudinal axis.

The greatest freedom of movement is given when the bearing surfaces on the valve cone and the contact surfaces on the tappet head have a common pivot point and thus form a ball joint with three degrees of rotational freedom. It should also be part of the scope of the invention that the pivoting movement of the valve cone relative to the tappet head is limited about one or two axes with a predefined orientation. For example, rotation of the valve plug about the longitudinal axis of the valve body group can be blocked.

Due to the freedom of rotation of the valve plug with respect to the tappet head, the valve plug can rotate about a center of motion/center to avoid misalignments between the longitudinal axis of components of the pressure control valve and an axis of a bore in the hydraulic line to be monitored by the valve assembly and/or the bore, in which the pressure control valve is installed. These misalignments can arise, for example, due to manufacturing tolerances. Manufacturing inaccuracies in the components of the pressure control valve according to the invention can also be compensated for by tilting/pivoting the valve cone.

In a preferred embodiment, the valve tappet or the sleeve is biased in the direction of the longitudinal axis in the direction out of the valve housing, i.e. in the direction from the bottom region of the valve housing towards the outer end region of the sleeve, by means of a second spring which is applied to the inner end of the valve tappet or . acts on the inner end region of the sleeve and is supported on the bottom region of the valve housing. In general, the intended biasing forces of the first spring and the second spring are different from one another, since each spring monitors a different function of the pressure control valve according to the invention. The preload force influences the limit value for the opening of the valve, which is usually different for both operating modes, i.e. for the pressure relief function and for the filling/feeding function. Since the pressure level for the pressure relief, especially for the high pressure limitation, and the feed pressure are usually very different, the strength of the two springs is also very different. A factor of 10 or even 20 between the high pressure level and the feed pressure level is not unusual.

Alternatively, the valve tappet can also be attached to the bottom area of the valve housing with its second end opposite the tappet head. In this configuration, only one spring is provided, which applies a biasing force to close the pressure control valve. The preload force of the spring determines the opening pressure required for both the activation of the pressure relief function of the valve and the activation of the feed function. So if a different limit value is required for the opening of the valve, the areas to which the pressure can be adjusted can act, can be changed to adapt the operating behavior of the valve.

In one embodiment, the inner sealing surface and the outer sealing surface of the valve cone both have a spherical shape and the centers of the two spherical sealing surfaces lie on the axis of rotation of the valve cone, but at a longitudinal distance from one another.

The center of rotation of the valve plug is defined by the coincident centers of rotation of the inner sealing surface of the valve plug and the concave bearing surfaces of the pin. In this case, contact of the outer sealing surface of the valve cone with a valve seat of a hydraulic line causes a rotation of the valve cone with respect to its center of rotation, since the axis of the valve seat of the conduit does not coincide with the longitudinal axis of the control valve according to the invention.

Alternatively, the pivot point of the valve cone can be defined by the pivot point of the bearing surfaces of the spoke and can be arranged at a distance from the center of the inner sealing surface of the valve cone. In this case, the orientation of the valve plug is influenced by the angular and/or linear offset between the longitudinal axis of the valve housing and the inner sealing surface of the valve plug, the position of which is determined by the orientation of the longitudinal axis of the valve plug. In addition, the angular and/or linear offset of the longitudinal axis of the valve housing with respect to a fluid line in which the valve is installed can determine the position of the valve cone, thereby causing rotation or tilting movement of the valve cone due to the longitudinal distance between the center of the supporting surfaces of the Valve cone and the center of the outer sealing surface is created. In any case, the pivot point of the valve plug around the tappet head is defined by the support surfaces of the spokes, which are guided through the contact surfaces on the tappet head.

However, it is also included in the invention that the inner and/or the outer sealing surface of the valve cone has a conical shape instead of a spherical shape.

According to the invention, the bottom area of the valve housing can be formed by an end cap that can be screwed into the cylindrical wall area. In this embodiment, the distance between the bottom portion of the valve housing and the cylindrical wall portion of the hollow sleeve is adjustable. This allows the size of the pressure chamber to be varied and thus the preload force of the second spring - if a second spring is provided - to be adjusted.

However, there are also other embodiments in which the preload force of the first spring and/or the preload force of the second spring is adjustable. For example, the spring seat for fastening the first spring to the valve pin, at the end of the tappet shaft opposite the tappet head, could be an adjustable disk which can be screwed along the longitudinal axis of the tappet shaft. This allows the distance between the spring seat at the outer end of the sleeve and the fixation at the shaft end to be varied and the preload force of the first spring to be adjusted. To adjust the preload force of the second spring, the bottom region of the valve housing, on which the spring rests, can be movable, for example due to its construction as an end cap. However, the bottom area can also have a movable element, such as a spring seat at one end of a screw, which is screwed into the end area and is accessible from the outside of the valve housing. By screwing the screw in or out, the longitudinal position of the spring seat can be changed and the preload force of the second spring can be adjusted.

In an alternative embodiment, the contact surfaces on the valve tappet head and the support surfaces on the spokes of the valve cone have a spherical shape with the same pivot point, which differs from the centers of the inner sealing surface and the outer sealing surface of the valve cone. As already mentioned, in this case a spherical connection is formed by the contact surfaces and the support surfaces, which makes it possible to tilt the valve cone with respect to the axis of the pin shaft.

According to a preferred embodiment of the invention, the common pivot point of the contact surfaces on the tappet head and the support surfaces on the spokes as well as the center of the inner sealing surface of the valve cone or the sleeve sealing contour of the hollow sleeve lies without any distance from one another on the longitudinal axis of the valve housing, i.e. on the longitudinal axis of the pressure control valve. As a result, the control valve according to the invention is able, by means of the tiltable valve cone, to compensate for manufacturing inaccuracies between the inner sealing surface and the outer sealing surface as well as tolerances of the sleeve sealing contour and misalignment between the longitudinal axis of the valve housing and the bore into which the valve housing is installed.

Alternatively, the common center of the contact surfaces of the tappet head and the supporting surfaces of the spokes does not have to be identical to the center of the inner sealing surface of the valve cone. From this center point, the center point of the outer sealing surface can be located along the longitudinal axis be standing. With this arrangement, the valve plug can be tilted in relation to the center of the contact/support surfaces. Contact of the outer sealing surface of the valve plug with a valve seat at the fluid line opening determines the final orientation/tilt angle of the valve plug.

Preferably, the center points of the inner sealing surface and/or the outer sealing surface are shifted along the longitudinal axis when the valve cone moves about its center point and when the valve compensates for misalignment. Since not all center points of the support surfaces of the valve cone, the inner sealing surface and the outer sealing surface are identical, a pivoting movement of the valve cone about one of the center points causes a displacement of the other center points in the direction of the longitudinal axis. The magnitude of the force required to move the valve plug and the length of the path the centers travel along the longitudinal axis are determined by the initial linear and/or angular displacement that must be compensated for.

In one embodiment of the invention, the valve cone has at least three spokes, each with a concave support surface. In general, the number of spokes and the cross-section of the spokes influence the stability of the valve plug and the flow area, especially the extent of free flow. As mentioned above, if each spoke has a concave support surface and the corresponding support surfaces on the ram head have a complementary convex shape, the support surfaces in conjunction with the contact surfaces form a spherical bearing. In general, it is desirable for pressure relief valves to have a large cross section for fluid flow.

According to the invention, the rotational position of the valve cone can be fixed about the longitudinal axis with respect to the valve tappet. This makes it easier to assemble the pressure control valve according to the invention and to mount it on a hydraulic line or a hydraulic unit. This also ensures reliable operation of the valve.

In another preferred embodiment, the spring force of the first spring is different from the spring force of the second spring. As already mentioned, the spring rate influences the preload force of the springs and therefore the limiting force required to compress the springs in order for the pressure relief valve to perform its function. In one embodiment of the invention, the first spring defines the opening pressure difference of the (high) pressure limiting function of the pressure control valve. The second spring defines the opening pressure difference for the feed function of the valve. Since the pressure limiting function is required in a high-pressure line and the feed function is provided in a low-pressure line of a hydraulic unit, the spring force of the first spring can preferably be higher than the spring force of the second spring. When the springs are compressed, parts necessary to perform the pressure relief function or the feed function of the pressure control valve can move against each other. Consequently, the spring force of the springs is one of the parameters that affects the response limits for the pressure relief function and the injection function.

The pressure control valve according to the invention can be integrated into a valve device. Since the valve housing can be designed so that it corresponds to the standard dimensions used in hydraulic units, the pressure control valve according to the invention can also be provided as a spare part for replacing prior art pressure control valves.

A valve device according to the invention has, for example, a first flow hole which opens into a second flow hole. In an exemplary embodiment, the second flow hole may be aligned perpendicular to the first flow hole. In other embodiments, the second flow hole may be aligned obliquely to the first flow hole. There is a valve mounting hole in the extension of the first flow hole. A pressure control valve according to the invention is inserted into the valve mounting hole in such a way that the outer sealing surface of the valve cone seals with a valve seat which is formed on the inside of the first flow hole, ie the side facing the second flow hole. This enables a fluid connection between the first flow hole and the pressure chamber in the pressure control valve via the inlet opening in the valve cone. The second flow hole connects the pressure regulating valve laterally to the outer end portion of the sleeve. In this initial state, the fluid connection between the first flow hole and the second flow hole is blocked by the contact of the outer sealing surface of the valve cone with the valve seat. As already mentioned, the axis of the valve receiving bore and the axis of the first flow bore often have a linear and/or angular offset due to manufacturing inaccuracies or tolerances, ie they are not identical. This means that the axes of the valve receiving bore and the first flow bore are not parallel to one another, ie the axes enclose an angle β that deviates from 180° and/or the axis of the valve opening The receiving bore has a linear offset to the axis of the first flow bore in the direction perpendicular to the longitudinal axis of the pressure control valve according to the invention.

In most operating states of the valve device, the pressure in the first flow hole and in the second flow hole is different. The valve device is in its initial position when neither the pressure relief function nor the feed function are activated. In a typical configuration, the pressure in the first flow hole acts on the portion of the outer sealing surface of the valve plug that is adjacent to the first flow hole and is carried by the remaining area of the outer sealing surface of the valve plug within the contact line/surface of the valve seat of the first flow hole limited to the outer sealing surface of the valve cone. The pressure of the first flow hole is conducted via the inlet opening of the valve cone into the cavity inside the valve cone and is further conducted via the interior of the sleeve into the pressure chamber next to the bottom region of the valve housing. The pressure of the second flow hole is applied to the part of the outer sealing surface of the valve cone that is adjacent to the second flow hole and is limited outside the contact surface between the outer sealing surface of the valve cone and the valve seat of the first flow hole. Consequently, the outer sealing surface of the valve cone is divided by the valve seat on the first flow hole into an inner area in which there is a (high) pressure in the first flow hole and into an outer area in which the pressure prevails in the second flow hole.

When a hydraulic pressure at the inlet port of the valve plug, i.e. a hydraulic pressure in the first flow bore, produces a force on the face(s) of the outer end portion of the sleeve high enough to compress the first spring, the pressure limiting function of the valve activated. The sleeve is lifted off the valve cone and moved towards the bottom area of the valve housing. An end stop or the bottom of the pressure chamber can limit the movement of the sleeve along the longitudinal axis to avoid damage to the first spring. In the pressure limiting function, a hydraulic fluid connection is established from the first flow hole to the second flow hole via the inlet opening, the cavity in the valve cone and the distance between the inner sealing surface of the valve cone and the sealing surface of the sleeve adjacent to the second flow hole. Too high a pressure from the first liquid bore is directed into the second liquid bore until the force generated by the hydraulic pressure in the first liquid bore is lower than the limit value defined by the first spring. In this situation, the valve cone moves towards the inner sealing surface of the valve cone due to the restoring force of the first spring until contact between the inner sealing surface of the valve cone and the sealing contour of the valve cone is restored.

When a hydraulic pressure in the second bore is higher than a hydraulic pressure in the first flow bore and when the pressure difference between the hydraulic pressure in the second bore and the pressure in the first flow bore is high enough to produce a force that the second If the spring can be compressed, the feed function is activated. In this case, the pressure forces that lift the valve plug from the valve seat are higher than the spring forces, and a fluid connection is established between the second flow hole and the first flow hole by moving the entire valve body group towards the bottom region of the valve housing. Hydraulic fluid can then be directed from the second flow hole to the first flow hole through the gap between the valve cone and the valve seat at the first flow hole. This reduces the pressure difference between the pressure in the second flow hole and the pressure in the first flow hole until the force generated by the pressure difference is too low to compress the second spring. When this condition is met, the valve body group is pressed toward the valve seat by the second spring and the valve automatically returns to its initial position, in which the fluid connection between the first flow hole and the second flow hole is blocked.

A valve device according to the invention can be used in hydraulic circuits of open or closed type. A valve device according to the invention can be integrated, for example, into hydraulic axial or radial piston units.

• 1 zeigt ein erfindungsgemäßes Druckbegrenzungsventil;
• 2 zeigt einen Ventilkegel eines erfindungsgemäßen Druckbegrenzungsventils;
• 3 zeigt eine Schnittdarstellung eines Ventilkegels eines erfindungsgemäßen Druckbegrenzungsventils;
• 4 zeigt einen Ventilstößel eines erfindungsgemäßen Druckbegrenzungsventils;
• 5 zeigt eine Detailaufnahme eines Stößelkopfes eines Ventilstößels eines erfindungsgemäßen Druckbegrenzungsventils;
• 6 zeigt eine erfindungsgemäße Ventilvorrichtung.

Preferred embodiments of a pressure control valve according to the invention and a valve device according to the invention are explained in more detail with reference to the attached figures in order to improve the understanding of the basic idea of the invention. The present embodiments do not limit the scope of the inventive idea of the invention, but merely represent a possible embodiment variant to which changes can be made within the scope of the knowledge of a person knowledgeable in the relevant field without departing from the scope of the invention. Therefore, all of these modes fications and changes covered by the claimed invention.

• 1 shows a pressure relief valve according to the invention;
• 2 shows a valve cone of a pressure relief valve according to the invention;
• 3 shows a sectional view of a valve cone of a pressure relief valve according to the invention;
• 4 shows a valve lifter of a pressure relief valve according to the invention;
• 5 shows a detailed view of a tappet head of a valve tappet of a pressure relief valve according to the invention;
• 6 shows a valve device according to the invention.

1 shows a pressure relief valve 1 according to the invention. The pressure relief valve 1 has a valve housing 2 with a cylindrical wall region 5. The central axis of the cylindrical wall area 5 defines a longitudinal axis 3 of the pressure relief valve 1. The valve housing 2 is closed on one side by a base area 4. In some embodiments, the bottom region 4 is movable in the direction of the longitudinal axis 3 with respect to the cylindrical wall region 5 of the valve housing 2. The bottom area 4 can be designed as an end cap 6, which is connected to the cylindrical wall area 5, for example by screwing.

A valve body group 8 is arranged inside the hollow cylindrical wall region 5 of the valve housing 2. The valve body group 8 has a hollow cylindrical sleeve 10, which is slidably housed in the cylindrical wall region 5 of the valve housing 2. A longitudinally inner end region 13 of the sleeve 10 seals against the inner peripheral surface of the valve housing 2. A longitudinally outer end section 12 of the sleeve 10 projects out of the valve housing 2 in the longitudinal direction. At the end of the sleeve 10 facing away from the bottom region 4, the outer end section 12 has a sleeve sealing contour 14. The outer end portion 12 further includes a shoulder that extends radially inwardly from the outer surface of the sleeve 10 and forms a spring seat 16. The shoulder does not extend to the longitudinal axis, but has a central cavity, which is designed, for example, as a through hole and is penetrated by a valve tappet 20, which is arranged coaxially inside the sleeve 10. The valve tappet 20 has a mushroom-shaped tappet head 22 at its end protruding from the sleeve 10. A thread is arranged on the opposite tappet shaft end 24, via which a spring tensioning element 17 is fastened to a tappet shaft 25 of the valve tappet 20.

The plunger head 22 has convex contact surfaces 23 at its end facing the sleeve or the bottom region 4 of the valve housing 2 plunger shaft 25. These contact surfaces 23 are in contact with the concave support surfaces 36 of a valve cone 30. The valve cone 30 has the general shape of a hollow truncated cone, which has an inlet opening 37 on its smaller diameter on the side facing away from the base region 4. A plurality of spokes 33 extend radially inward from the outer surface into a cavity of the valve cone. At the radially inner ends of the spokes 33, support surfaces 36 are formed, which are shaped complementary to the contact surfaces 23 on the plunger head 22. The combination of convex contact surfaces 23 and concave support surfaces 36 forms a type of ball joint with at least one degree of freedom in the direction of rotation. The contact surfaces 23 and the complementary concave support surfaces 36 are preferably designed so that they form a ball joint with two rotational degrees of freedom. The third degree of freedom, ie the rotation about the longitudinal axis, is blocked by the positioning surfaces 27 on the plunger head 22 relative to the radial inner ends of the spoke (see also 4 and 5 ). This allows the valve cone 30 to be tilted in relation to the center of the ball joint. This allows the pressure relief valve 1, by means of the tiltable valve cone 30, to compensate for tolerances and inaccuracies between the various components of the pressure relief valve 1, which could negatively affect the functionality of the valve 1, and misalignments between the longitudinal axis 3 of the pressure relief valve 1 and an axis of the hydraulic fluid bore, which to be monitored by the pressure relief valve 1 according to the invention.

The hollow, conical valve plug 30, which has rotational symmetry with respect to an axis of rotation 35, further has an outer sealing surface 34 and an inner sealing surface 32.

In the assembled state, the valve cone 30 is pulled in the direction of the base region 4 against the sleeve sealing contour 14 by a first spring 40, which is arranged radially within the sleeve 10 between the spring seat 16 and the spring tensioning element 17 around the valve tappet 20. This ensures contact between the inner sealing surface 32 and the sleeve sealing surface 14. The biasing force of the first spring 40 can be adjusted, for example, by adjusting the longitudinal position of the spring tensioning element 17. If the valve cone 30 is held in its position by any force, for example by high pressure is generated, which acts on the valve cone 30 at the end of the end face (s) 15 of the sleeve, the biasing force of the first spring 40 determines the force that is required to separate the sleeve 10 with the sleeve sealing contour 14 from the inner sealing surface 32 of the valve cone 30 to take off.

In some embodiments, the center of the inner sealing surface 32 of the valve plug 30 is identical to the center defined by the combination of the concave support surfaces 36 on the spokes 33 of the valve plug 30 and the convex contact surfaces 23 on the tappet head 22. In this case, even after the pressure relief valve 1 has been assembled, the valve plug 30 is capable of tilting or being tilted with respect to the common center point.

A second spring 45 is arranged on the plunger shaft 25 between the bottom region 4 of the valve housing and the plunger shaft end 24 opposite the plunger head 22. The second spring 45 is also preloaded. The biasing force of the second spring 45 determines the force required to move the entire valve body group 8 in the longitudinal direction with respect to the valve housing 2 and determines the contact pressure of the outer sealing surface 34 of the valve cone on a valve seat.

In order to fasten the valve body group 8 in the longitudinal direction to the valve housing 2 and to prevent the preloaded second spring 45 from pushing the valve body group 8 out of the valve housing 2, a locking ring 7 can be provided. The locking ring 7 has, for example, fork-shaped ends which penetrate the housing 2 in the radial direction and cooperate with a groove in the outer peripheral surface of the sleeve 10 (not shown). The interaction between the groove and the ends of the locking ring 7 sets predefined limits to the mobility of the sleeve 10 in relation to the valve housing 2, so that at least the inner end region 13 of the sleeve 10 remains inside the valve housing 2, even if the pressure relief valve is not, for example installed in a valve device.

2 shows a valve cone 30 of a pressure relief valve 1 according to the invention in a detailed view. 3 is a sectional view of the in 2 shown valve cone 30. The valve cone 30 has, for example, three spokes 33, which are distributed equidistantly around the circumferential surface of the truncated cone representing the valve cone 30. Due to the chosen perspective, only two of the three spokes 33 are visible in the sectional view. In the embodiment shown, all three support surfaces 36 have a concave support surface with a common center at their radially inner ends and face the inlet opening 37.

The outer sealing surface 34 is arranged in the front area, the area with the smaller diameter of the truncated cone, near the inlet opening 37, through which hydraulic fluid can enter the cavity inside the valve cone 30. The incoming hydraulic fluid can be directed through the valve cone through the space between the spokes 33 to the outlet opening 38 in the bottom surface of the valve cone 30. The inner sealing surface 32 of the valve cone 30 is arranged on the inner circumferential surface in the area of the larger diameter of the truncated cone-shaped valve cone 30. The inner sealing surface 32 has a spherical shape, for example with a center on the longitudinal axis 3. This center can be located away from the center of the outer sealing surface 34 or at the same location. The center of the concave support surfaces 36 should be arranged in the same longitudinal position as the center of the inner sealing surface 32 in order to create an equally sized and equally oriented sealing contour for the sleeve sealing contour 14 when the valve cone is tilted from its initial position in which the axis of rotation 35 of the valve cone is aligned with the longitudinal axis 3 of the valve housing 2.

4 shows a valve tappet 20 of a pressure relief valve 1 according to the invention. 5 shows a detailed view of the tappet head 22 of the valve tappet 20 according to 4 . The valve tappet 20 is rotationally symmetrical with respect to the longitudinal axis 3. The tappet head 22 has convex contact surfaces 23. The convex shape of the contact surfaces 23 corresponds to the concave shape of the support surfaces 36, ie they are preferably complementary. Furthermore, the plunger head 22 has flat positioning surfaces 27, which can interact with flat surfaces on the inside of the spokes 33 of the valve cone 30 during assembly of the pressure relief valve 1. Therefore, in the embodiment shown, the rotational position of the valve cone 30 about the longitudinal axis 3 of the valve tappet 20 is fixed. A plunger shaft 25 extends from the plunger head 22 in the longitudinal direction. A thread is provided at the end 24 of the plunger shaft 25 opposite the plunger head 22, for example for fastening a spring tensioning element 17.

6 shows a valve device 100 with a pressure relief valve 1. The valve device 100 has a first flow bore 110 with a first flow bore axis 113. A second flow hole 120 is arranged perpendicular to the first flow hole 110. Opposite the first flow hole 110 is a valve receiving hole 130 with a valve opening Reception bore axis 133 is provided for receiving a pressure relief valve 1 according to the invention. The opening of the first flow hole 110 into the second flow hole 120 defines a valve seat 140, which is designed to cooperate with the outer sealing contour 34 of the valve cone 30 of the pressure relief valve 1 according to the invention.

A pressure relief valve 1 according to the previously described embodiments is fixed in the valve receiving bore 130, for example by screwing. The second spring 45 presses the movable valve body 8 against the valve seat 140 to fluidly separate the first flow hole 110 from the second flow hole 120. The pressure in the first flow hole 110 acts on the part of the outer surface of the valve cone 30, which is limited by the contact surface of the outer sealing surface 34 with the valve seat 140. The liquid from the first flow hole 110 can enter the valve body group 8 via the inlet opening 37. As a result, this or a reduced pressure prevails inside the valve body group 8 and in the pressure chamber 9. The pressure in the second flow hole 120 acts on the part of the outer surface of the valve cone 30 which is located outside the contact surface on the valve seat 140 and which is in fluid communication with the second flow hole 120.

In practice, the axis 133 of the valve mounting hole has an angular and/or linear offset to the axis of the first flow hole 113, due to inaccuracies in the manufacture of the individual parts or openings or due to inhomogeneous material properties, such as deviating thermal expansion coefficients. According to the invention, the valve cone 30 can be tilted relative to the center defined by the combination of the concave support surfaces 36 with the convex contact surfaces 23 on the tappet head 22. The sealing function of the valve can be negatively influenced by the angular and/or linear offset between the axis of the first flow hole 113 and/or the axis of the valve mounting hole 133 and/or the longitudinal axis of the valve housing 3. The tilting movement of the valve plug can compensate for these shortcomings to provide a reliable valve device 100 with less stringent manufacturing quality requirements. The pressure relief valve 1 according to the invention not only allows the tilting movement of the valve cone 30 in order to adapt the valve cone alignment, i.e. the alignment of the valve cone rotation axis 35 to the offset first flow bore axis 113, so that the rotation axis 35 of the valve cone 30 both the first flow bore axis 113 and the longitudinal axis 3 of the valve housing 2 cuts. Since the outer and also the inner sealing surfaces 34 and 14 preferably have a spherical contour, good sealing contact with a cylindrical valve seat, e.g. the valve seat 140 on the first flow hole 110 or the sealing contour 14 on the end face of the sleeve 10, is also ensured. when the axis of rotation 35 of the valve cone 30 is inclined relative to one or both of the aforementioned axes.

In a pressure limiting function, i.e. when the pressure in the first flow channel 110 is higher than the pressure in the second flow channel 120 and the difference between the pressure in the first flow channel 110 and the pressure in the second flow channel 120 is higher than a predefined limit value, the sleeve sealing contour 14 of the inner sealing surface 32 of the valve cone 30 is lifted and a fluid connection is established between the two flow bores 110, 120. In the present embodiment, the limit value is influenced by the biasing force of the first spring 40 and by the surfaces on the valve cone 30 and on the sleeve 10 on which the pressure prevailing in the flow holes 110, 120 can act. The valve plug 30 is held in position in contact with the valve seat 140 by the force generated by the pressure prevailing in the first flow bore 110. The valve cone 30 remains in its rotational position, which ensures that the valve seat 140 is sealed, even if the sleeve 10 is not in contact with the valve cone 30. However, since the sleeve 10 moves only along the longitudinal axis 3, the sealing contact between the inner sealing surface 32 and the sleeve sealing contour 14 is restored when the sleeve 10 returns to its original position. In addition, a tilting movement of the valve cone 30 during pressure limitation is corrected when the sleeve 10 returns to the inner sealing surface 32 of the valve cone 30.

In the in 6 In the embodiment shown, the second spring 45, which is arranged between the base 4 and the sleeve 10, also contributes with its biasing force to the limit value that must be exceeded by the force generated by the pressure difference in order to activate the pressure limiting function.

The valve device 100 is also capable of fulfilling a feeding function. The pressure in the second flow hole 120 is higher than the pressure in the first flow hole 110 and the difference between the pressures is higher than a second limit value. The limit value is influenced by the preload force of the second spring and the surfaces on the valve cone 30 and the sleeve 10 on which the pressure can act. Preferably, the spring rate of the first spring 40 is higher than the spring rate of the second spring 45. Therefore, the In this case, valve body 8 can be viewed almost as a rigid component. If the limit value is exceeded, the entire valve body group 8 is lifted from the valve seat 140 and liquid from the second flow hole 120 can enter the first flow hole 110. When the valve body group 8 returns to its original position, the valve plug 30 slides back into the valve seat 140 by performing a tilting movement with respect to the center of the support surfaces 36 if the valve plug 30 was moved in orientation during the feeding function.

As can be seen from the above disclosure, the attached figures and claims, the pressure control/overpressure valve 1 according to the invention with a feed function and the valve device 100 offer many possibilities and advantages over the prior art. The person skilled in the art will further recognize that further modifications and changes can be made to a pressure control valve 1 according to the invention and a valve device 100 according to the invention without departing from the scope of the present invention. Therefore, all such modifications and changes are within the scope of the claims and are covered by them. It should be further understood that the examples and embodiments described above are for illustrative purposes only and that various modifications, changes, or combinations of embodiments known to one skilled in the art are within the spirit and scope of the present application.

Reference symbol list

1

Pressure relief valve

2

Valve housing

3

Longitudinal axis

4

floor area

5

Cylindrical wall area

6

End cap

7

Circlip

8th

Valve body group

9

Pressure chamber

10

sleeve

12

Outer end section

13

Inner end section

14

Sealing contour sleeve

15

End face sleeve

16

Spring seat

17

Spring tensioning element

20

Valve tappet

22

Pestle head

23

Convex contact surfaces

24

Tappet shaft end

25

plunger shaft

27

Positioning surface

30

valve cone

32

Inner sealing surface

33

spoke(s)

34

External sealing surface

35

Axis of rotation of the valve cone

36

Concave support surface

37

Inlet opening

38

Exhaust opening

40

First feather

45

Second feather

100

Valve device

110

First flow hole

113

Axis of the first flow hole

120

Second flow hole

130

Valve mounting hole

133

Valve mounting hole axis

140

Valve seat

Claims (17)

Pressure relief valve (1) for a hydraulic line, which has a valve housing (2) with an inner cylindrical wall area (5) which defines a longitudinal axis (3) and a base area (4) which closes the valve housing (2) at one end, wherein the cylindrical wall region (5) accommodates a valve body group (8) which has: ◯ a hollow cylindrical sleeve (10) which is movably arranged coaxially within the valve housing (2), a longitudinally inner end region (13) of the sleeve (10 ) seals with the housing (2) and thereby forms a pressure chamber (9) with the base region (4), and an outward-pointing sleeve sealing contour (12) on an outer end region (12) in the longitudinal direction, which protrudes from the valve housing (2). 14) and a radially inwardly directed spring seat (16) is arranged; ◯ a valve tappet (20) which is arranged coaxially in the sleeve (10) and protrudes from the outer end section (12) of the sleeve (10), a first end having a tappet head (22) on which a convex contact surface (23 ) educated is which faces the second end of a plunger shaft (25); ◯ a first spring (40), which is arranged coaxially within the sleeve (10) and around the valve lifter shaft (25), is attached at one end to the free valve lifter end (24) and at the other end to the spring seat (16 ) is supported on the outer part of the sleeve (10), so that the first spring (40) can bias the valve tappet (20) in the direction of the pressure chamber (9); and ◯ a conical, hollow valve cone (30) with an inner sealing surface (32) for sealing with the sleeve sealing contour (14), an outer sealing surface (34) around an inlet opening (37) of the valve cone (30) for sealing with a Valve seat (140) of a hydraulic line, and a plurality of radially inwardly directed spokes (33) with concave support surfaces (36) facing the inlet opening (37); wherein the plunger head (22) can be brought into contact with the spokes (33) of the valve cone (30) and the valve cone (30) is pulled against the outer sealing contour (14) of the sleeve (10) by means of the first spring (40), to seal with the inner sealing surface (32); and wherein the contact surface (23) on the tappet head (22) guides the support surfaces (36) on the spokes (33) in such a way that the valve cone (30) can be pivoted about axes perpendicular to the longitudinal axis (3). Pressure relief valve (1). Claim 1 , wherein the valve tappet (20) or the sleeve (10) acts by means of a second spring (45) which acts on the inner end (24) of the valve tappet (20) or the inner section (13) of the sleeve (10) and on Bottom area (4) of the valve housing (2) is supported, is biased towards the outside of the valve housing (2) in the direction of the longitudinal axis (3). Pressure relief valve (1). Claim 1 , wherein the valve tappet (20) is attached to the bottom region (4) of the valve housing (2) with its second end (24), which is opposite the tappet head (22). Pressure relief valve (1) according to one of the preceding claims, wherein the inner sealing surface (32) and the outer sealing surface (34) of the valve cone (30) have a spherical shape, and wherein the centers of the spherical sealing surfaces (32, 34) on the axis of rotation (35 ) of the valve cone (30), but at a longitudinal distance from one another. Pressure relief valve (1) according to one of the preceding claims, wherein the bottom region (4) of the valve housing (2) is formed by an end cap (6) which can be screwed into the cylindrical wall region (5). Pressure relief valve (1) according to one of the preceding claims, wherein the biasing force of the first spring (40) and/or the biasing force of the second spring (45) is adjustable. Pressure relief valve (1) according to one of the preceding claims, wherein the contact surfaces (23) on the valve tappet head (22) and the contact surfaces (36) on the spokes (33) of the valve cone (30) have a spherical shape with the same pivot point, which is equal to the center of the inner sealing surface (32) of the valve cone (30). Pressure relief valve (1). Claim 7 , wherein the center of the outer sealing surface (34) of the valve cone (30) is different from the center of the inner sealing surface (34) of the valve cone (30). Pressure relief valve (1). Claim 7 or 8th , whereby the center points of the outer sealing surface (34) and the inner sealing surface (34) of the valve cone (30) as well as the center points of the contact surfaces (23) on the valve tappet head (22) and the support surfaces (36) on the spokes (33) of the valve cone ( 30) can be displaced in the direction of the longitudinal axis (3) when the valve cone (30) is tilted by a force acting on the outer sealing surface (34). Pressure relief valve (1) according to one of the preceding claims, wherein the valve cone (30) has at least three spokes (33), each of which has a concave support surface (36). Pressure relief valve (1) according to one of the preceding claims, wherein the rotational position of the valve tappet (20) about the longitudinal axis (3) is fixed with respect to the valve cone (30). Pressure relief valve (1) according to one of the Claims 2 or 4 until 11 , wherein the spring force of the first spring (40) is higher than the spring force of the second spring (45). Valve device (100) with a first flow bore (110) which opens into a second flow bore (120), wherein a pressure relief valve (1) according to one of the preceding claims is inserted in a valve fastening bore (130) in an extension of the first flow bore (110). in that the outer sealing surface (34) of the valve cone (30) seals with a valve seat (140) formed on the inside of the first flow hole (110), whereby a fluid connection between the first flow hole (110) and the pressure chamber (9) via the inlet opening (37) of the valve cone (30) is made possible, and the second flow hole (120) connects the pressure relief valve (1) at the outer end Section (12) of the sleeve (10) is connected laterally, and the axis (133) of the valve mounting hole (130) and the axis (113) of the first flow hole (110) have a linear and / or angular offset. Valve device (100). Claim 13 , wherein the sleeve (10) can be lifted off the valve cone (30) and moved towards the bottom region (4), thereby enabling fluid connection from the first flow bore (110) to the second flow bore (120) when hydraulic pressure at the inlet opening (37) a force is generated on the front surface(s) (15) of the outer end region (12) of the sleeve (10) which is high enough to force the first spring (40) or both the first Compress the spring (40) and the second spring (45). Valve device (1). Claim 13 , wherein a fluid connection from the second flow bore (120) to the first flow bore (110) is established when a hydraulic pressure in the second bore (120) is higher than a hydraulic pressure in the first flow bore (110), whereby the valve body group (8 ) is moved towards the bottom area (4) when the pressure force acting on the valve cone (30) in an area outside the valve seat (140) is high enough to generate a force that can compress the second spring (45). Hydraulic circuit of open or closed type with a valve device (100) according to one of Claims 13 until 15 . Hydraulic axial or radial piston unit with a valve device (100) according to one of Claims 13 until 15 .

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