CN112901794B

CN112901794B - Expansion valve

Info

Publication number: CN112901794B
Application number: CN202011406017.9A
Authority: CN
Inventors: 斯文·德尔曼; 阿德里安·埃斯拉瓦·奥拉德雷; 丹尼尔·赖曼; 托尼·施奈德
Original assignee: Eco Holding 1 GmbH
Current assignee: Eco Holding 1 GmbH
Priority date: 2019-12-04
Filing date: 2020-12-03
Publication date: 2023-01-13
Anticipated expiration: 2040-12-03
Also published as: CN112901794A; DE102020129282A1

Abstract

The invention relates to an expansion valve which can be operated by a stepping motor and is used for being installed in a valve installation space, comprising: a housing; a hollow rod disposed in the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle, which is arranged inside the hollow rod and is driven by the rotor, such that a rotational movement of the spindle is converted by means of a screw connection into an axial movement for opening and closing the expansion valve, which, when the expansion valve is mounted in the valve mounting space, is adjacent to a side of the valve base body facing away from the housing, for pressure equalization the housing interior chamber being connected with the fluid inlet chamber by means of a first pressure equalization channel having a first and a second channel region, the first channel region being in the valve base body and the second channel region being in the hollow rod, the first and the second channel regions being connected to one another. The invention further relates to a method for manufacturing such an expansion valve.

Description

Expansion valve

Technical Field

The present invention relates to an expansion valve.

Background

An expansion valve, also referred to as a throttle valve, is generally a device which reduces the pressure of the flowing fluid by means of a local narrowing of the flow cross section and thus causes a volume increase or expansion. Typically, an expansion valve comprises a mechanism that converts rotational motion into axial motion to open and close the expansion valve. For the axial movement for opening and closing the expansion valve, both end points need to be defined or determined by means of a stop structure.

Such expansion valves are well known in the art. A stop arrangement for a motorized valve is known, for example, from JP 3328530 B2. In this valve, the degree of opening of the valve seat in the valve main body is controlled by rotating the rotor of the motor by energization of the stator of the motor. The stator is fastened to the outer periphery of the housing. The rotation of the rotor is converted into linear motion by the threaded action of the inner and outer bolts.

The stopper structure defining two end points at the opening and closing of the expansion valve includes a stopper, an engagement portion, and a ring-shaped guide pin.

The stop is arranged vertically on the back side of the cover at the upper end region of the housing at a position remote from the center.

The engagement portion has elongated shafts extending on opposite sides of a valve stem constructed integrally with the rotor. Here, the rod is inserted into a guide path having a helical middle section and projecting regions on the upper and lower end sections, wherein the upper projecting region is mounted at the upper end region of the rod and wherein the lower projecting region is bent upwards.

The stop structure further comprises an annular guide pin comprising an annular area rotating about the helical middle portion about once and an arm extending in the outer circumferential direction below the annular area so as to be able to contact a stop arranged in the helical groove of the guide path.

Here, when the annular guide pin moves along the spiral groove of the guide path, an upper end region of the annular region of the guide pin comes into contact with the protruding region of the guide part. Further, as the guide pin moves downward along the helical groove of the guide path, the arm of the guide pin contacts an engagement portion configured on the lower protruding area.

Overall, the above-described structure of the expansion valve known from the prior art is very complicated. However, this complexity is not an isolated problem. On the contrary, all expansion valves known in the prior art have the drawback that they have a complex and cumbersome structure to fulfil their function. This complicated structure also inevitably results in the inability to simply replace the expansion valve or its components.

Furthermore, in the known expansion valve there is also the problem that the expansion valve is subject to high wear. This results in that the expansion valves known from the prior art have to be replaced relatively frequently and often completely.

In addition to a simpler construction which enables a simpler exchange of the entire expansion valve and its components, an expansion valve with overall low wear is therefore also desirable.

Another disadvantage of the known expansion valves is that their manufacture is cumbersome.

Disclosure of Invention

It is therefore an object of the present invention to provide an expansion valve which overcomes the above-mentioned problems and disadvantages of the prior art. The object of the invention is, in particular, to provide an expansion valve which is designed to be low-wearing on the one hand and compact on the other hand. Furthermore, it is an object of the invention to provide an expansion valve in which particularly simple replacement is possible. Another object of the invention is to provide a valve which, despite low wear, compact construction and simple replaceability, enables pressure equalization between the different chambers inside the valve.

Furthermore, it is an object of the present invention to provide a method for manufacturing an expansion valve which is less cumbersome than methods known in the prior art.

The solution according to the invention is to provide an expansion valve operable with a stepper motor, comprising: a housing; a hollow rod disposed in the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle arranged inside the hollow rod and drivable by the rotor such that a rotational movement of the spindle is convertible by a threaded connection into an axial movement for opening and closing the expansion valve; and a screw body having a thread, which is arranged on the circumferential surface of the hollow shaft and can be driven by means of the rotor, wherein stop bodies are provided on the hollow shaft, which stop bodies are movably arranged in the thread of the screw body and predetermine an upper end position and a lower end position of the central spindle as part of a spindle stop arrangement.

The central spindle is in particular designed as a threaded spindle, which together with other elements (here the internal thread of the hollow rod) serves to convert a rotary movement of the rotor into a translational movement.

For this purpose, the central spindle is connected to the rotor. The helix is a separate element rather than part of the hollow rod. The screw is also connected to the rotor so that the rotor can drive the screw.

The stop body is arranged in particular on the circumferential surface of the hollow rod and preferably abuts against the first (upper) stop element when the central spindle is in the lower end position and preferably abuts against the second (lower) stop element when the central spindle is in its upper end position. The stop body can be, for example, a rod-shaped element. Whether the upper or lower end position of the spindle is determined depends on the pitch of the screw and the pitch of the spindle.

By driving the screw body with the thread (separately) by means of the rotor and arranging the stop body such that it is movable in the thread, a particularly compact structural form of the expansion valve can be achieved.

According to an advantageous further development of the invention, the hollow rod has a longitudinal groove on the circumferential surface, wherein the stop body is designed as a sliding ring which is arranged in the thread path of the helical body in a rotationally fixed manner and is movable in the axial direction by means of the longitudinal groove.

Depending on the direction of rotation, the slip ring moves axially up and down along the hollow rod (inside the longitudinal groove).

Since the slide ring can be moved up and down in the longitudinal groove, the overall size of the expansion valve can be reduced, so that the expansion valve can be constructed even more compactly. In particular, a simple construction is provided with a high functional reliability by means of the longitudinal grooves and the slip rings.

Furthermore, since the slide ring is fixed in the longitudinal groove, the group of screw body and slide ring is also fixed on the circumferential surface of the hollow rod. Therefore, the guide groove functions together with the slip ring as a loss prevention portion.

According to an advantageous development of the invention, the spindle stop arrangement is formed by the interaction of the screw and the slip ring.

According to an advantageous development of the invention, the slide ring has a radially inwardly extending projection which is designed to extend in the longitudinal groove and to serve there as a rotation prevention element.

The radially inwardly extending projection offers the simple possibility of preventing the slide ring from twisting, so that the slide ring can be reliably moved axially in the longitudinal groove.

According to an advantageous development of the invention, the screw has a first stop element extending in the axial direction of the screw and a second stop element extending in the axial direction of the screw.

The axial direction of the screw is understood to be the direction which extends along the axis around which the screw is wound. In the installed state, the axis is at least substantially aligned concentrically with the rotational axis of the hollow shaft and the rotational axis of the spindle. In particular, the first stop element extends in a direction opposite to the direction in which the second stop element of the screw extends. Here, however, the two directions are the axial directions of the spiral body.

According to an advantageous further development of the invention, the lower end position of the spindle is determined when the first stop element is in contact with the stop body, wherein the upper end position of the spindle is determined when the second stop element is in contact with the stop body together with the maximum torsion angle of the screw.

If the screw is a rigid or non-rotationally elastic body, the maximum angle of torsion of the screw is zero, so that the upper end position of the spindle is determined when the second stop element comes into contact with the stop body.

However, if the screw body is rotationally elastic, the spindle can still be moved to the extent that the elasticity of the screw body allows after the second stop element has come into contact with the stop body. Thus, the movement of the spindle in the upward direction is suppressed when the second stop element is in contact with the stop body.

As an alternative thereto, the upper end position of the central spindle can also be determined when the first stop element is in contact with the stop body, wherein the lower end position of the spindle is determined when the second stop element is in contact with the stop body and, if appropriate, together with the maximum torsion angle of the screw body. Whether the upper or lower end position of the central spindle is determined depends on the pitch of the helix and the pitch of the central spindle. Depending on, inter alia, whether the thread is right-handed or left-handed. The first stop element is also the upper spindle position only if the pitch of the central spindle differs from the pitch of the helical body. If the central spindle and the screw have the same screw direction, the travel paths of the central spindle and the slip ring are opposite. Accordingly, the first stop element also specifies the lower spindle position.

According to an advantageous development of the invention, the slide ring is designed as a cylindrical spiral and has an upper end and a lower end opposite the upper end, wherein the upper end is in contact with the first stop element and wherein the lower end is in contact with the second stop element.

Since the slide ring is designed as a cylindrical screw, a particularly good retention of the slide ring inside the screw body can be achieved. Further, a slip ring may be formed, i.e., a cylindrical screw may be formed such that the upper end and the lower end intersect each other. This means that the cylindrical spiral is formed over an angular range of more than 360 degrees, wherein the intersection is here an angular range of more than 360 degrees. By means of this intersection of the ends and the number of turns of the helix, the maximum number of possible revolutions can be predefined and/or limited.

According to an advantageous development of the invention, the screw is connected by means of a first stop element to an adapter element for rotation with the rotor when the rotor rotates, wherein the adapter element connects the rotor to the spindle for driving the spindle into rotation when the rotor rotates.

The adapter element is connected to the spindle in a force-fitting manner, for example by means of a press connection, a welded connection, or a form-fitting manner. The adapter element can be connected to the rotor, for example, in a form-fitting manner. For this purpose, the adapter element is configured rotationally asymmetrically when viewed in cross section. For example, the outer shape of the adapter element, viewed in cross section (that is to say along the axis of rotation R), can be triangular, quadrangular or generally polygonal, for example also toothed. The inner shape of the rotor, as seen in cross section, is of course of complementary design to the shape of the adapter element.

That is to say that the first stop element of the screw body fulfills a dual function and, in addition to functioning as a stop element, also serves as a driving element (that is to say a connecting element) for the rotor or the adapter.

By not directly but indirectly transferring the rotation of the rotor via the adapter, it is for instance also possible to produce different expansion valves (with e.g. different rotors) with as many identical components as possible.

According to an advantageous development of the invention, the spiral body is a torsion spring which is embodied in the form of a helical spring made of steel.

The production of the spiral is thereby particularly advantageous.

According to an advantageous development of the invention, the hollow rod is made of plastic, preferably Polyphenylene Sulfide (PPS) or Polyetheretherketone (PEEK), or brass or bronze.

When using plastic, weight is saved in the expansion valve compared to using metal material. Furthermore, the plastics PPS and PEEK are high-performance materials, so that they can be used permanently in the high temperature range (up to 240 degrees) and in the short term even up to 300 ℃. Thus, the expansion valve can also be used in extreme conditions without fear of failure of the expansion valve. According to an advantageous development of the invention, the expansion valve further has a sleeve element with a receiving region and a valve needle, wherein the punch-like end region of the central spindle, the compression spring and the force transmission element are completely received in the receiving region.

Since the expansion valve is designed with a sleeve element which, on the one hand, fulfills the function of the valve needle and, on the other hand, provides a receiving region, a particularly compact design of the expansion valve can be achieved. Despite the compact embodiment, all functions of the expansion valve can be reliably achieved.

According to an advantageous development of the invention, the force transmission element is designed and arranged in such a way that it transmits the axial force from the central spindle to the sleeve element via the compression spring by contact with the central spindle, wherein the force transmission element, viewed in cross section, is mushroom-shaped in such a way that the torque is not transmitted from the central spindle or is transmitted from the central spindle to the force transmission element only to a limited extent.

Since the force transmission element is mushroom-shaped, the contact point with the central spindle, i.e. the force transmission point, is reduced. At the force transmission point, the torque is then transmitted to the force transmission element only to a limited extent (by friction). Overall, this also results in a particularly low-wear expansion valve.

According to an advantageous development of the invention, the housing and the side of the valve base body facing the housing define a housing interior, wherein a hollow shaft interior is formed in the interior of the hollow shaft, wherein the fluid inlet chamber is arranged adjacent to the side of the valve base body facing away from the housing in the state of the expansion valve mounted in the valve mounting space, wherein a first pressure equalization channel is provided for pressure equalization between the fluid inlet chamber and the housing interior, wherein the first pressure equalization channel has a first channel region and a second channel region, and wherein the second channel region is formed by the longitudinal groove.

A particularly compact construction of the expansion valve can thereby also be achieved. In particular, by assigning a second function to an existing component, components can be saved.

The longitudinal grooves thus here not only assume the function of guiding the slide ring, but also the function of pressure compensation channels. The longitudinal groove therefore fulfills a dual function, since it enables the guiding of the slide ring on the one hand and additionally forms part of the second pressure compensation channel.

According to an advantageous further development of the invention, the second pressure compensation duct for pressure compensation between the hollow shaft interior and the housing interior is arranged in the region of the longitudinal groove and of the greatest radial extent of the hollow shaft interior.

This also enables a reliable pressure equalization between the hollow shaft interior and the housing interior.

Another solution according to the present invention is to provide an expansion valve operable with a stepper motor, comprising: a housing; a hollow rod disposed in the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle arranged inside the hollow rod and drivable by the rotor such that a rotational movement of the spindle is convertible by a threaded connection into an axial movement for opening and closing the expansion valve; an adapter element arranged between the rotor and the main shaft for transmitting torque from the rotor to the main shaft; and a screw which is arranged on the outer circumference of the hollow rod and can be set in a rotary motion by means of an adapter element, wherein the screw has an axially extending first stop element which is arranged in an eccentric opening of the adapter element.

The structure of the expansion valve is more versatile as a whole, since the adapter element is arranged between the main shaft and the rotor. That is, for example, different rotors may be used. In addition, the adapter assumes a second function, since it drives the screw, that is to say places the screw in rotary motion.

The adapter element has a central axis of rotation R, wherein the eccentric opening is defined such that said eccentric opening is formed eccentrically from said central axis of rotation R.

According to an advantageous development of the invention, the adapter element has a plate-shaped base region and a receiving region for the central spindle, which extends axially in the center from the plate-shaped base region.

The axially extending receiving region has the advantage that the bore tolerances can be enlarged, since the elongate guide leads to a smaller possible inclination of the components relative to one another.

The connection between the spindle and the adapter element is realized, for example, after alignment at the upper side of the spindle. The connection can be made by means of laser welding, wherein preferably a plurality of welding points are provided.

Since only the base region is designed in the form of a plate, a weight saving can additionally be achieved in comparison with an adapter element which is designed completely in the form of a plate.

According to an advantageous development of the invention, the through-hole in the center along the rotational axis R of the adapter element is configured to receive an upper region of the spindle.

The central through hole thus extends along the rotational axis R of the adapter element. The central through-opening is preferably circular, viewed in cross section, in order to enable a particularly simple alignment of the spindle stop arrangement or the upper stop. However, the central through hole need not be a circular opening. In contrast, the central through-opening, viewed in cross section, cannot be rotationally symmetrical. For example, the through-opening can be triangular, quadrangular or generally polygonal, for example also toothed, as viewed in cross section (that is to say along the axis of rotation R).

In this way, forces can be transmitted from the adapter element to the spindle or more precisely to the upper region of the spindle in a particularly simple manner. Of course, the upper region of the spindle, viewed in cross section, is complementary to the shape of the central through hole.

According to an advantageous development of the invention, the outer shape of the adapter element is rotationally asymmetrical with respect to the axis of rotation R.

According to an advantageous development of the invention, the eccentric opening is arranged in a plate-shaped base region, wherein the plate-shaped base region preferably also has a further eccentric opening.

Since the eccentric opening is arranged in the plate-like base region of the adapter element, it can be designed particularly far from the center of the adapter element (i.e. the axis of rotation). A better force transmission (lever arm) can be achieved by a greater distance between the eccentric opening and the axis of rotation R.

By providing further eccentric openings, further functions can be integrated into the adapter element.

According to an advantageous development of the invention, the eccentric opening is formed as a slot.

The slot has the advantage that it can be produced more simply, since it can be introduced into the adapter element or into the plate-like base region of the adapter element from the side (i.e. at right angles to the axis of rotation).

According to an advantageous development of the invention, at least one of the further eccentric openings is arranged in such a way that it balances the pressure in the interior of the housing above the adapter element and below the adapter element.

The adapter element therefore additionally also fulfills the function of pressure compensation. Since the member is (again) configured to be able to perform a plurality of functions, the number of members as a whole can be reduced.

According to an advantageous development of the invention, the screw body has a thread, wherein the hollow rod has a longitudinal groove on the circumferential surface, and wherein the slip ring is arranged in the thread of the screw body in a rotationally fixed manner and movably in the axial direction by means of the longitudinal groove.

Since the slide ring can be moved up and down in the longitudinal groove, the overall size of the expansion valve can be reduced, so that the expansion valve can be constructed more compactly. Also, a simple construction is provided with greater functional reliability by means of the longitudinal grooves and the slip rings.

Since the slide ring is fixed in the longitudinal groove, the group of screw body and slide ring is also fixed on the circumferential surface of the hollow rod. Therefore, the guide groove functions together with the slip ring as a loss prevention portion.

According to an advantageous development of the invention, the spindle stop arrangement is formed by the interaction of the screw and the slip ring, which predefines the upper and lower end positions of the central spindle.

According to an advantageous development of the invention, the spiral body has a second stop element which extends opposite the first stop element in the axial direction.

According to an advantageous development of the invention, the slip ring is designed as a cylindrical screw and has an upper end and a lower end.

When the slide ring is configured as a cylindrical spiral, a particularly good retention of the slide ring inside the spiral can be achieved. Further, a slip ring may be formed, that is, a cylindrical screw may be formed such that upper and lower end portions thereof intersect each other. Thus, the cylindrical helix is configured over one full circle (over 360 degrees). Here, the intersection is an area beyond a full circle. By means of this intersection of the ends and the number of turns of the helix, the maximum number of possible revolutions can be predefined and/or limited.

According to an advantageous development of the invention, a projection extending radially inward is formed on one of the two ends.

The radially inwardly extending projection offers a simple possibility of preventing the slide ring from twisting, so that the slide ring can be reliably moved axially in the longitudinal groove.

According to an advantageous development of the invention, the radially inwardly extending projection of the slip ring is designed to extend in the longitudinal groove of the hollow rod and to serve there as a rotation prevention means.

According to an advantageous development of the invention, the lower end position of the spindle is determined when the first stop element is in contact with the upper end, and the upper end position of the spindle is determined when the second stop element is in contact with the lower end together with the maximum angle of twist of the screw.

If the helix is a body that cannot be pre-tensioned in the direction of rotation (i.e. rigid and not rotationally elastic), the maximum twist angle of the helix is zero. The upper end position of the spindle is then determined when the second stop element is in contact with the stop body. However, if the screw is rotationally elastic (i.e., can be pretensioned in the rotational direction), the spindle can still move after the second stop element has come into contact with the stop body (because the spindle pretensions the screw).

This means that the upward rotation of the spindle is suppressed when the second stop element is in contact with the stop body.

As an alternative thereto, the upper end position of the spindle can also be determined when the first stop element is in contact with the stop body, wherein the lower end position of the spindle is determined when the second stop element is in contact with the stop body and together with the maximum torsion angle of the screw.

Whether the upper or lower end position of the spindle is determined depends on the pitch of the helix. Depending on, inter alia, whether the thread is right-handed or left-handed. The first stop element is also the upper spindle position only if the pitch of the spindle differs from the pitch of the screw. If the main shaft and the screw have the same screw direction, the travel paths of the main shaft and the slip ring are opposite. Accordingly, the first stop element also specifies the lower spindle position.

According to an advantageous development of the invention, the spiral body is a torsion spring which is designed in the form of a helical spring made of steel.

The spiral body can thus be produced extremely simply (and cost-effectively).

According to a further aspect of the present invention, there is provided an expansion valve operable by a stepping motor, the expansion valve comprising: a housing; a hollow rod disposed in the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle arranged inside the hollow rod and drivable by the rotor such that a rotational movement of the spindle is convertible by a threaded connection into an axial movement for opening and closing the expansion valve; a sleeve element having a receiving region in which a central spindle, a compression spring and a force transmission element are at least partially received, and a valve needle, wherein the receiving region of the sleeve element is closed by means of a bushing, wherein the spindle is made of a first material and the bushing is at least partially made of a second material different from the first material, wherein the second material has a lower hardness than the first material.

Since the sleeve element has the valve needle and the receiving region, i.e. the valve needle body, is sleeve-shaped, a particularly compact design of the expansion valve can be achieved. This is particularly due to the fact that the elements required for transmitting the force to the valve needle can be arranged in the receiving region in a space-saving manner.

In operation, there are components that perform a rotational movement and components that do not perform a rotational movement. In particular, the spindle performs a rotational movement, while the sleeve element performs as little rotation as possible. By bringing the element performing the rotation into contact with the element not performing the rotation, wear is generated on the element.

In the expansion valve according to the invention, this problem is solved on the one hand by the fact that there is a selected tribological pairing between the elements which are in contact with one another and which move relative to one another. The wear can thus be controlled such that the wear occurs mainly on one of the participating components. In addition, the member may optionally be provided as a wear part which is easy to replace.

The bushing enclosing the sleeve element may thus be a wear part which is simply replaceable. If the bushing is worn, the bushing can simply be replaced and the entire sleeve element together with the valve needle does not have to be replaced. Thus, costs can be significantly reduced during maintenance.

The frictional pairing is selected such that the bushing is made of a softer material than the first material, that is to say a material with a lower hardness. Therefore, wear occurs mainly at the bushing. Although there may be a possibility of replacing the bushing, the bushing is advantageously dimensioned such that it allows wear over the service life of the valve.

Overall, the expansion valve according to the invention provides a compact design, in which a targeted and controlled wear is ensured structurally. The wear part itself may be easily replaceable.

The bushing is in particular pressed into the sleeve element, that is to say by means of a press-fit connection.

In the sense of the present invention, an annular or hollow cylindrical element is understood as a bushing. Advantageously, however, the sleeve element is a hollow cylindrical element, characterized in that,

the sleeve element extends further in the axial direction (rotation axis) than the annular element. Accordingly, the hollow cylindrical wear element provides more abradable material than the annular wear element.

According to an advantageous development of the invention, the first and second materials are metals or metal alloys.

According to an advantageous development of the invention, the second material is a copper alloy, preferably brass, and the first material is steel, in particular stainless steel.

Particularly preferably, the second material is a sintered material. For example, the material may be sintered bronze. Sintered materials are to be understood as meaning those materials which have a large number of pores which can be filled with a lubricant. For example, 10 to 40 volume percent, preferably 15 to 30 volume percent of the liner can be made up of the holes.

A particularly good relationship between wear and costs can be achieved in particular by material pairing of stainless steel and brass. On the one hand, the second material must not be too soft to wear out too quickly, and on the other hand, the second material must not be too hard so that the element consisting of the first material is not damaged.

Particularly preferably, the force transmission element is also made of the first material (e.g. stainless steel). Furthermore, the sleeve element is also preferably constructed of the first material (i.e., stainless steel).

According to an advantageous development of the invention, the force transmission element has a head region and a shaft region, wherein the force transmission element is arranged such that the contact for transmitting the axial force from the central spindle takes place in a point-like manner in a central region of the head region.

By means of this punctiform transmission, the contact surface (for transmitting torque) between the spindle and the force transmission element is kept as small as possible. Due to the small contact surface that is maintained, the spindle slips during rotation and the force transmission element is not set in rotation. On the other hand, axial forces can also be reliably transmitted from the spindle to the force transmission element by means of a point-like contact.

This means that a torque interruption occurs at the contact surface between the force-transmitting element and the central spindle. In other words, a torque acts on the rotor driven by the stator, which torque is transmitted to the main shaft, for example, in a force-fitting manner (via an adapter). The rotational movement is converted into an axial movement of the spindle by means of a threaded connection of the spindle. In this case, only such an axial movement of the valve needle is desired, i.e. no rotational movement of the valve needle is desired there.

According to an advantageous development of the invention, the compression spring is arranged locally on the circumferential surface of the rod region of the force transmission element.

Since the compression spring is arranged on the circumferential surface of the rod region, it is guided from the inside by means of the rod region. On the other hand, the compression spring is guided from the outside by means of the inner surface of the receiving region of the sleeve element. In other words, the compression spring is reliably guided between the rod region of the force transmission element and the receiving region of the sleeve element.

The compression spring does not necessarily have to make positive contact with both elements. Conversely, it is also conceivable to form a gap between the circumferential surface of the rod region and the compression spring and between the compression spring and the inner surface of the receiving region. However, the compression spring is guided to such an extent that tilting during compression of the spring is avoided.

According to an advantageous development of the invention, the compression spring is a cylindrical helical spring.

The compression spring is thereby particularly advantageous in terms of its production and can be reliably arranged around the circumferential surface of the rod region.

According to an advantageous further development of the invention, the axial length of the rod region is designed to be so long that the rod region comes into contact with the sleeve bottom of the sleeve element when an axial force is exceeded, which results in the compression spring being compressed by a predefined spring travel.

This means that when the pressure spring is compressed by a predefined spring travel, the axial force can be transmitted directly from the force transmission element to the bottom of the sleeve. Thus, a maximum travel limitation can be achieved in the event of a mechanical stop failure, i.e. a spindle-stop-arrangement failure, or in the event of an overload of the valve.

The rod region therefore also fulfils a dual function, the force transmission element fulfilling multiple functions. The force transmission element can firstly effect a torque decoupling of the sleeve element from the main shaft. Furthermore, the force transmission element or its rod region is guided. On the one hand, the force transmission element or its rod region guides the compression spring in the axial direction and thus prevents a bending or generally an asymmetrical deformation of the compression spring. In addition, the rod region provides the maximum travel limit described above.

According to an advantageous further development of the invention, the spindle has a punch-like end region which is designed and arranged in such a way that it is in contact with the force transmission element for transmitting the axial force, wherein an upper region of the punch-like end region is in frictional contact with the bushing.

This means that the lower region (more precisely the lower side) of the punch-like end region comes into contact with the force transmission element and the upper region of the punch-like end region comes into frictional contact with the bushing. The punch-like end region is therefore arranged between the bushing and the force transmission element.

According to an advantageous development of the invention, the receiving region is configured such that it completely receives the bushing, the punch-like end region, the compression spring and the force transmission element.

At the bottom of the receiving area, i.e. directly above the bottom of the sleeve, a pressure spring is arranged. A force transmission element is arranged above the compression spring and a punch-like end region of the spindle is arranged above the force transmission element. A bushing is again arranged on the punch-like end region, wherein the bushing closes the receiving region overall.

A particularly compact embodiment of the expansion valve is thereby achieved.

According to an advantageous development of the invention, the expansion valve has a valve seat, wherein the valve base body is an integrally formed body which at least partially receives the valve seat, the sleeve element and the hollow rod.

The valve base body is therefore designed as a replaceable valve cartridge (cartridge). Since the valve base body only has to be removed from the valve installation space, a simplified valve replacement can be achieved. Furthermore, the compactness is also improved because a plurality of functions are integrated in the valve base body.

Furthermore, such an integrally formed valve base body offers the possibility of integrating the valve into a user-specific installation space by adjusting only one component (valve base body exterior). This results in cost savings, since the same components can be used for different expansion valves. In addition, the diversity of components is reduced, so that more cost can be saved. The complexity of assembling the expansion valve is also reduced.

According to an advantageous development of the invention, the valve base body has a valve seat receiving region in the lower region and a receiving region in the upper region, which receiving region is designed to receive the hollow rod and the sleeve element.

The valve base body therefore has receiving regions which enable the elements of the expansion valve to be integrated into the valve base body as simply as possible.

According to an advantageous development of the invention, the sleeve element is arranged at least partially inside the hollow rod in the receiving region.

The installation space is also reduced by the receiving region, as viewed in the axial direction of the expansion valve.

According to an advantageous development of the invention, the force transmission element is designed such that it does not absorb or only absorbs a limited torque of the spindle.

This limitation occurs at the point-like contact surface between the force transmission element and the central spindle.

According to an advantageous development of the invention, the expansion valve has a spindle stop arrangement which limits the rotational movement of the spindle between the upper end position and the lower end position.

According to an advantageous development of the invention, the spindle stop arrangement is formed by the interaction of the screw body and the stop body.

According to another aspect of the present invention, there is provided an expansion valve operable by a stepping motor, the expansion valve comprising: a housing; a hollow rod disposed on the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle arranged inside the hollow rod and drivable by the rotor such that a rotational movement of the spindle is convertible by a threaded connection into an axial movement for opening and closing the expansion valve; and a sleeve element having a valve needle that can be pressed into a valve seat, wherein the valve base is an integrally formed body that at least partially receives the valve seat, the sleeve element and the hollow stem.

The valve base body is therefore designed as a valve cartridge (column). On the one hand, this provides the advantage of enabling a simplified replacement of the valve, since only the valve base body needs to be removed from the valve installation space. On the other hand, a particularly high compactness can be achieved since a plurality of functions are integrated in the valve cartridge, i.e. in the valve base body.

Furthermore, such an integrally formed valve base body offers the possibility of integrating the valve into a user-specific installation space by adjusting only one component. Thus, a plurality of different valves is created, which preferably differ only in the valve base body.

The inner regions of the different valve bases are always of identical design, so that the functional components in the inner regions can be installed in a plurality of different expansion valves. The contour of the valve base body can be adapted to the specific installation space of the user, so that different valve base bodies are different here.

This makes it possible to save costs in particular in the production, since the same components can be used for different expansion valves. The complexity in assembling the expansion valve is also reduced.

The valve base body therefore has a receiving region in order to be able to integrate the functionally necessary elements of the expansion valve into the valve base body as simply as possible. The installation space is also reduced by the receiving region, as viewed in the axial direction of the expansion valve.

This saves additional installation space. The receiving areas may be arranged in a plane (with the rotation axis R as a normal). In the receiving region, the hollow rod is first arranged radially inward. The sleeve element is then arranged radially inwards, i.e. inside the hollow rod. Then, for example, a part of the central spindle and/or a force transmission element or the force transmission element is arranged radially inward again.

This results in a particularly compact construction. Therefore, since the plurality of elements are arranged on one plane, the length in the axial direction can be reduced. That is, the length of the expansion valve can be shortened as compared with the prior art. Especially in the automotive industry, the installation space is often extremely limited, so that with shorter valves more possibilities for arrangement are created.

According to an advantageous development of the invention, the valve base body has a housing seat which is arranged and formed radially around an upper region of the valve base body or the upper region in such a way that it receives the housing in a closed manner.

Therefore, the housing can reliably enclose all the components inside thereof.

According to an advantageous development of the invention, the valve base body has a lower seal receiving region and an upper seal receiving region.

By providing two different seal receiving areas, a reliable seal can be achieved even if the valve base body is constructed in one piece.

According to an advantageous development of the invention, the valve base body has means for pressure equalization.

This means that the valve base body is designed in such a way that means for pressure compensation (for example pressure compensation channels) are integrated in the valve base body. By the targeted integration of the pressure compensation channels or the pressure compensation means, the valve base body can be realized as an integrated component without affecting the function of the expansion valve.

According to an advantageous development of the invention, the housing and the side of the valve base body facing the housing define a housing interior, wherein a first means for pressure equalization is arranged as a first pressure equalization channel between the housing interior and the fluid inlet chamber.

The first pressure compensation channel preferably has a first channel region which is arranged at least in some regions in the valve base body and a second channel region which is arranged at least in some regions in the hollow shaft, wherein the first channel region and the second channel region are connected to one another by a circumferentially surrounding connecting region.

During operation, imbalances between the forces, in particular above and below the components located between the forces, must be prevented as far as possible. This is achieved, for example, by directing the high pressure prevailing at the inlet upwards. Thus, in general, a pressure increase in one of the chambers of the expansion valve, which would disturb the function of the expansion valve, should be avoided by the pressure equalization channel.

According to an advantageous development of the invention, the expansion valve has a second pressure compensation channel for pressure compensation between the hollow shaft interior and the housing interior, wherein the second pressure compensation channel is formed by a hollow-rod-shaped hollow body and a hollow-rod-shaped hollow body

The hollow shaft lumen is configured within the hollow shaft.

According to an advantageous development of the invention, the sleeve element has a receiving region in which the punch-like end region of the central spindle, the compression spring and the force transmission element are completely received, wherein the receiving region is arranged completely within the valve base body, viewed in cross section.

This saves installation space. In the receiving region, the hollow rod is initially arranged radially inward. The sleeve element is then arranged radially inwards, i.e. inside the hollow rod. The punch-like end region of the central spindle, the compression spring and the force transmission element are then again arranged radially inward.

This results in a particularly compact construction. Therefore, since the plurality of elements are arranged on one plane, the length in the axial direction can be reduced.

According to an advantageous development of the invention, the expansion valve has a third pressure compensation channel which is arranged between the receiving region of the sleeve element and a lower inner region of the valve base body in which the valve needle is designed to be axially movable.

The third pressure compensation channel serves for pressure compensation between a cavity formed in the receiving region of the sleeve element and the lower interior region of the valve base body. The lower inner region of the valve base body is in turn connected to the fluid inlet chamber via the fluid opening, so that pressure equalization can also take place here by means of the fluid opening.

A reliable and sufficient pressure equalization between all chambers which are formed or arranged inside the expansion valve and partly also adjacent to the expansion valve is thus achieved in a structurally simple way and manner.

According to an advantageous development of the invention, the force transmission element has a head region and a shaft region, wherein the force transmission element is arranged such that the contact with the central spindle takes place in a central region of the head region in a contact-free manner.

No or almost no torque can be transmitted via this point-like contact surface between the spindle and the force transmission element. Therefore, the main shaft slips when rotating, and the force transmission member does not rotate. The axial force can be reliably transmitted from the spindle to the force transmission element by means of a point-like contact. As a result, a torque interruption occurs at the contact surface between the force transmission element and the central spindle.

Since the compression spring is arranged on the circumferential surface of the rod region, it is guided by the rod region. On the other hand, the pressure spring is guided from the outside by means of the inner surface of the receiving region of the sleeve element.

The pressure spring does not have to contact both elements. Instead, it is also conceivable to form a gap between the circumferential surface of the rod region and the pressure spring and between the pressure spring and the inner surface of the receiving region. However, the compression spring is guided to such an extent that skewing of the spring during compression thereof can be avoided.

As a cylindrical helical spring, the compression spring is particularly advantageous in terms of its production and can be arranged reliably around the circumference of the rod region.

According to an advantageous further development of the invention, the length of the rod region is designed to be so long that the rod region comes into contact with the sleeve bottom of the sleeve element when an axial force is exceeded, which results in the compression spring being compressed by a predefined spring travel.

This means that when the pressure spring is compressed by a predefined spring travel, the axial force can be transmitted directly from the force transmission element to the bottom of the sleeve. Thus, a maximum travel limitation can be achieved in the event of a mechanical stop failure, i.e. a spindle-stop-arrangement failure, or in the event of an overload of the valve. Thus, the force transmission element also fulfils a plurality of functions. The force transmission element can firstly decouple the torque of the sleeve element from the spindle. Furthermore, the force transmission element or its rod region guides the compression spring in the axial direction and thus prevents a bending or generally an asymmetrical deformation of the compression spring. In addition, the rod region provides the maximum travel limit described above.

An aspect according to the present invention is also to provide an expansion valve for installation in a valve installation space, which can be operated using a stepping motor, the expansion valve having: a housing; a hollow rod disposed on the housing; a valve base carrying the hollow stem and enclosing the housing; a rotor drivable by means of a stator; a central spindle which is arranged inside the hollow shaft and can be driven by the rotor in such a way that a rotational movement of the spindle can be converted by means of a screw connection into an axial movement for opening and closing the expansion valve, wherein the housing and a side of the valve base body facing the housing define a housing interior space, wherein the hollow shaft interior space is formed inside the hollow shaft, wherein in a state in which the expansion valve is mounted in the valve mounting space, a fluid inlet space is arranged adjacent to a side of the valve base body facing away from the housing, wherein for pressure equalization the housing interior space is connected to the fluid inlet space by means of a first pressure equalization channel, wherein the first pressure equalization channel has a first channel region which is arranged at least partially in the valve base body and a second channel region which is arranged at least partially in the hollow shaft, wherein the first channel region and the second channel region are connected to one another by means of a circumferentially encircling connecting region.

Thus, the expansion valve has a plurality of chambers formed inside or adjacent to the expansion valve. During operation, imbalances between the forces, in particular above and below the components located between the forces, must be prevented as far as possible. This is achieved, for example, by directing the high pressure present at the inlet upwards. Thus, pressure increases in one or more of the chambers of the expansion valve that disturb the function of the expansion valve should generally be avoided by the pressure equalization channel.

In the assembled state of the expansion valve, the hollow rod is arranged in the valve base body (precisely in one accommodation region or in said accommodation region of the valve base body). The first channel region is at least partially arranged in the valve base body, and the second channel region is at least partially arranged in the hollow rod.

In order to be able to achieve a pressure balance between the first and second channel regions, they must be in fluid connection. This fluid connection is realized by a circumferentially encircling connection region. Since the connection region is designed as a circumferentially encircling connection region which forms the necessary fluid connection between the two regions, it is no longer necessary to align the two regions with one another during assembly of the valve base body and the hollow rod. This simplifies assembly and avoids errors during assembly that could lead to failure of the expansion valve.

According to an advantageous development of the invention, the circumferentially circumferential connecting region is a circumferential undercut which is arranged on the inner circumference of the receiving region of the valve base body.

In this case, such a circumferential undercut makes possible a reliable (fluid) connection between the first channel region and the second channel region.

According to an advantageous further development of the invention, the circumferentially surrounding connecting region is a circumferential chamfer which is arranged on the outer circumference of the hollow rod.

This has the advantage, in particular, that the chamfering is simpler and therefore more cost-effective to produce than a circumferential undercut in the receiving region.

If particularly rapid pressure equalization is required, a circumferential undercut and a circumferential chamfer can also be provided.

According to an advantageous further development of the invention, the second channel region is designed as a longitudinal groove which extends in the hollow shaft from a region arranged in the valve base body to a region which is not arranged in the valve base body.

The longitudinal grooves can be produced particularly simply, in particular longitudinal grooves in which the slip ring, already described, moves axially. The longitudinal groove thus also fulfills a dual function, since it is not only designed as a second channel region, but also serves to guide a slide ring which, as part of the spindle-stop arrangement, performs the function of an expansion valve.

According to an advantageous development of the invention, the expansion valve has a second pressure compensation channel for pressure compensation between the hollow shaft interior and the housing interior, which second pressure compensation channel is formed at least in some sections by a second channel region.

In other words, the area of the second channel area also forms the area of the second pressure equalization channel.

According to an advantageous development of the invention, the second pressure compensation channel is arranged in the region of the longitudinal groove and of the greatest radial extent of the hollow shaft interior.

This means that the second pressure equalization channel is formed on the bottom of the longitudinal groove. This relates in particular to the opening in the bottom of the longitudinal groove.

Thus, the longitudinal groove may serve not only as a second passage area, but also as part of a second pressure equalization passage, providing pressure equalization between the hollow shaft interior and the housing interior in addition to providing pressure equalization between the fluid entry cavity and the housing interior.

The second channel region of the first pressure compensation channel and the second pressure compensation channel can be formed at the same time when the longitudinal groove is introduced into the hollow shaft which is formed with a hollow shaft interior.

According to an advantageous development of the invention, the expansion valve has an adapter element which is arranged between the rotor and the main shaft for transmitting torque from the rotor to the main shaft, wherein the adapter element has at least one eccentric opening which is provided such that the eccentric opening balances the pressure in the housing interior above the adapter element and below the adapter element.

By means of the eccentric opening in the adapter element, it is also possible to quickly and easily equalize the pressure in the interior of the housing, that is to say between the upper region (above the adapter element) and the lower region (below the adapter element). This further improves the functional reliability of the expansion valve.

According to an advantageous further development of the invention, the expansion valve has a third pressure compensation duct, which is arranged between a receiving region of the sleeve element and a lower inner region of the valve base body, the sleeve element having a valve needle of the expansion valve, in which valve base body the valve needle is designed to be axially movable and which is connected to the fluid inlet chamber via the fluid opening.

The third pressure compensation channel thus serves for pressure compensation between the cavity formed in the receiving region of the sleeve element and the lower inner region of the valve base body. The lower inner region of the valve base body is in turn connected to the fluid inlet chamber via the fluid opening, so that pressure equalization can also take place here via the fluid opening.

A reliable and sufficient pressure equalization between all spaces which are formed or arranged inside the expansion valve and which are also partly adjacent to the expansion valve (e.g. the fluid inlet chamber) is thus achieved in a structurally simple manner.

According to an advantageous development of the invention, the punch-like end region of the central spindle, the compression spring and the force transmission element are accommodated in the receiving region of the sleeve element.

This results in a particularly compact design of the expansion valve, wherein all functions can be fulfilled, however.

According to an advantageous development of the invention, the force transmission element is designed and arranged in such a way that it transmits the axial force from the central spindle to the sleeve element via the compression spring by contact with the central spindle, wherein the force transmission element, viewed in cross section, is mushroom-shaped.

No or hardly any torque can be transmitted via this point-like contact surface between the spindle and the force transmission element. Therefore, the main shaft slips when rotating, and the force transmission member does not rotate. The axial force can be reliably transmitted from the spindle to the force transmission element by means of the point-like contact surface. As a result, a torque interruption occurs at the contact surface between the force transmission element and the central spindle.

The valve base body is thus designed as a cartridge. On the one hand, this provides the advantage of enabling a simplified replacement of the valve, since only the valve base body needs to be removed from the valve installation space. On the other hand, a particularly high compactness can be achieved since a plurality of functions are integrated in the valve cartridge, i.e. in the valve base body.

Furthermore, such an integrally formed valve base offers the possibility of integrating the valve into a user-specific installation space by adjusting only one component. This makes it possible to save costs in particular in the production, since the same components can be used for different expansion valves. The complexity of assembling the expansion valve is also reduced.

The solution according to the invention is also to provide a method for manufacturing an expansion valve, comprising the steps of: providing a hollow bar; and introducing a longitudinal slot into the hollow bar.

According to an advantageous development of the invention, the second pressure compensation channel is formed in the hollow shaft during the introduction of the longitudinal groove.

By introducing the second pressure compensation channel at the same time, the otherwise additionally required work step for separately introducing the second pressure compensation channel is saved.

Further advantages of the invention will emerge from the description and the drawings.

The invention is explained in more detail below with the aid of a description of embodiments and with reference to the drawings. Further advantageous embodiments and combinations of features of the invention emerge from the following description.

Drawings

The drawings that illustrate the embodiments show:

fig. 1 is a longitudinal section of an expansion valve according to the present invention in a state of being installed in a valve installation space;

fig. 2 is a detailed longitudinal section of a moving mechanism of an expansion valve according to the present invention;

fig. 3 is a schematic view of an adaptation element of an expansion valve according to the invention;

fig. 4 is a detailed longitudinal section of an adapter element and a rotor of an expansion valve according to the invention;

fig. 5 is a schematic view of a guide spring of an expansion valve according to the invention;

FIG. 6 is a schematic view of a slip ring of an expansion valve according to the present invention;

FIG. 7 is a top view of the slip ring of FIG. 6;

FIG. 8 is a schematic view of a hollow stem of an expansion valve according to the present invention;

fig. 9 is a schematic view of the main shaft-stop-geometry of an expansion valve according to the invention;

fig. 10 is a longitudinal section of a force transmitting and torque limiting mechanism of an expansion valve according to the present invention;

fig. 11 is a longitudinal section of a sleeve member of an expansion valve according to the present invention;

fig. 12 is a schematic view of a force transmitting element of an expansion valve according to the invention;

fig. 13 is a schematic view of a pressure spring of an expansion valve according to the invention;

fig. 14 is a longitudinal section of a valve base body of the expansion valve according to the present invention;

FIG. 15 is a schematic view of the valve base of FIG. 14;

fig. 16 is a detailed longitudinal section of a valve base body of the expansion valve according to the present invention; and

fig. 17 is a detailed longitudinal section of a hollow stem of an expansion valve according to the present invention.

Detailed Description

Fig. 1 shows a longitudinal section through an expansion valve 1 according to the invention in an exemplary embodiment. For the purposes of description, the upper side 2 and the lower side 3 are defined in fig. 1. The upper side 2 and the lower side 3 are also used to describe the individual components, respectively, the entire arrangement of which is visible in fig. 1.

The expansion valve 1 includes a valve base 5 and a housing 4. In fig. 1, the expansion valve 1 is shown in a state in which it is fitted in the valve installation space 43. A cavity is generally understood as a valve installation space 43 into which the expansion valve 1 should be or will be fitted.

Since the valve base body 5 is an integrally configured body, it can be inserted into the valve mounting space 43 in a cylindrical manner. Accordingly, the entire expansion valve 1 can be simply mounted into and dismounted from the valve mounting space 43.

In a state where the expansion valve 1 is mounted in the valve mounting space 43, a fluid passage 46 is formed. The fluid channel extends in fig. 1 from a side region (on the left in fig. 1) toward the valve base body 5 and forms a fluid inlet chamber 27 around a lower region of the valve base body 5 (i.e., toward the lower side 3).

The fluid inlet chamber 27 is connected to a lower interior region 42 of the valve base 5 via a fluid opening 40. The valve needle 20 of the expansion valve 1 is also arranged in the lower inner region 42.

When the expansion valve 1 is opened, a fluid passage 46 is formed from a side region of the expansion valve 1, through the fluid inlet chamber 27, through the fluid bore 40, through a lower inner region 42 of the valve base body 5 and through a valve opening closable by means of the valve needle 20 towards a region below the expansion valve 1.

The housing 4 is arranged at an upper side portion (i.e., toward the upper side 2) of the valve base 5. In particular, the housing 4 is sleeve-shaped.

All functional elements or components of the expansion valve 1 are arranged in the housing 4 or in the valve base 5. The housing 4 is radially enclosed by a stepping motor or stator, not shown here.

The valve base body 5 closes the housing 4 on the underside 3. In the housing 4, a rotor 6 (of a stepping motor) is arranged, which transmits its rotation to a central spindle 8.

In fig. 1, the rotation is transmitted from the rotor 6 to the central spindle 8 via the adapter element 13. The central spindle 8 has an external thread which is connected to an internal thread of the hollow shaft 7 as a threaded connection 9.

By means of the screw connection 9, the central spindle 8 is moved axially downwards (that is to say from the upper side 2 to the lower side 3) or upwards (that is to say from the lower side 3 to the upper side 2) along the axis of rotation R. Therefore, the rotational motion of the rotor 6 can be converted into the axial motion by the moving mechanism.

A spiral 12 is constructed around the hollow rod 7. In the construction shown in fig. 1, the screw 12 is configured as a guide spring 12. Reference numeral 12 is used here for the guide spring and for the screw.

The stop body extends in the screw body 12, i.e. in the thread 16 of the screw body. The stop body is designed here as a sliding ring 17.

The guide spring 12 and the slide ring 17 form a spindle stop geometry which predetermines an upper (axial) end position and a lower (axial) end position of the central spindle 8. The function of the spindle/stop arrangement will be explained in further detail below with reference to fig. 2 and 9.

The lower part of the central spindle 8, i.e. towards the underside 3, is accommodated in a sleeve element 21. The sleeve element 21 itself is accommodated in the valve base body 5. Furthermore, the lower region of the hollow rod 7 is also accommodated in the valve base body 5.

In particular, as shown in fig. 1, the sleeve element 21 is partially housed in the hollow stem 7, which is in turn partially housed in the valve base 5. That is, the inner peripheral surface of the valve base 5 contacts the outer peripheral surface of the hollow rod 7. In addition, the inner circumferential surface of the hollow rod 7 is in contact with the outer circumferential surface of the sleeve member 21.

The sleeve element 21 has a valve needle 20 on a lower region. The sleeve element 21 is a one-piece body, i.e. the valve needle 20 is of sleeve-like design.

The valve needle 20 is seated in the valve seat 34, wherein by lifting from the valve seat 34 (upwards, i.e. towards the upper side 2) the opening through the valve seat 34 is released and fluid can flow through the opening.

Fig. 1 shows the valve needle 20 in its installed state, in which it is pressed sealingly against the valve seat 34.

Elements for transmitting forces and limiting torques between the main shaft 8 and the sleeve element 21 are provided in the sleeve element 21. These elements will be described in more detail with reference to fig. 10.

Fig. 2 shows the upper part of the expansion valve 1 in more detail. In particular, fig. 2 shows a rotor 6, which is connected via an adapter 13 to a central spindle 8, which in turn is connected via a threaded connection 9 to the hollow rod 7.

As shown in fig. 2, the guide spring 12 is arranged on the circumferential surface 10 of the hollow rod 7. In particular, the guide spring 12 is a coil spring shown in fig. 5. The helical spring has a first stop element 14 and a second stop element 15. Two

stop elements

14, 15 are arranged at respective ends of the guide spring 12, which is designed as a helical spring. In particular, a first stop element 14 extends axially upwards from the upper end of the helical spring, while a second stop element 15 extends axially downwards from the lower end of the guide spring 12.

As can be seen in fig. 2, the first stop element 14 is connected to the adapter element 13. This also means that the guide spring 12 or the spiral 12 can rotate together with the adapter element 13. For this purpose, the adapter element 13 has an eccentric opening 13c (see fig. 3) into which the first stop element 14 can be or has been inserted.

As shown in fig. 1, the second stop element 15 is oriented toward the valve base body 5. The second stop element 15 can preferably be slid (schleifen) on the base body 5 during operation. Alternatively, a circular recess can be formed in the base body 5, in which recess the second stop element 15 of the spiral 12 or of the guide spring 12 extends and is guided.

As shown in fig. 3, the adapter element 13 has a plate-like base region 13a and a receiving region 13b for the central spindle 8. The receiving region 13b extends axially in the direction of the axis of rotation R in the center of the plate-shaped base region 13a (see fig. 4).

The rotor 6, the adapter element 13, the screw 12 and the central spindle 8 rotate about the axis of rotation R.

The adapter element 13 has a plurality of eccentric openings 13c, which are formed eccentrically, i.e. away from the center, in the plate-shaped base region 13 a. In fig. 3, four eccentric openings 13c in the form of long holes are formed on the outer circumference of the plate-shaped base region 13 a. The design of the eccentric opening 13c as a long hole offers advantages in particular in connection with manufacture.

The upper end region of the guide spring 12, i.e. the first stop element 14, extends into one of the eccentric openings 13c. The remaining eccentric opening 13c in the plate-like base region 13a of the adapter element 13 can be used, for example, to ensure a sufficient pressure equalization between the housing interior 28 above the adapter element 13 and the housing interior 28 below the adapter element 13.

A central through-hole 13d is formed in the interior of the receiving region 13b of the adapter element 13, into which an upper region of the central spindle 8 can be received. Viewed in cross section, this upper region of the spindle 8 is formed complementary to the central through-opening 13 d. Viewed in cross section means here that the two components are viewed along the axis of rotation R.

For the purpose of force transmission, it is conceivable that the two elements are not designed in a circular manner in cross section, but rather are not designed in a rotationally symmetrical manner. A simple transmission of torque from the adapter element 13 to the central spindle 8 can thus be achieved. For example, the central through opening 13d can be polygonal in shape, preferably quadrangular in shape. However, in general, each non-rotationally symmetrical configuration is conceivable in order to easily transmit torque. Preferably, however, the cross-section is circular and the force transmission is effected, for example, by a welded connection.

As shown in fig. 4, the outer periphery of the plate-like base region 13a is connected to the rotor 6. The torque of the rotor 6 is thereby transmitted to the adapter element 13. As can also be seen in fig. 4 and 2, the upper region of the rotor 6 has a stop, so that the adapter element 13 cannot slide through the rotor 6. This is advantageous in particular during assembly and serves to avoid errors.

The connection between the rotor 6 and the adapter element 13 can be material-locked, form-fit or force-fit. It is important here that torque can be transmitted from the rotor 6 to the adapter element 13. In principle, it is also conceivable to form the adapter element 13 and the rotor 6 as a one-piece component.

In fig. 2, a cross-sectional view of a slide ring 17 can be seen, which extends in the thread 16 of the guide spring 12.

Larger views of the slip ring 17 are given in fig. 6 and 7. Here, it can be seen that the slide ring 17 is designed as a spiral-shaped element. In particular, the slip ring 17 is designed as a cylindrical screw which is wound in the installed state about the axis of rotation R.

As shown in fig. 6, the slip ring 17 has an upper end 17a and a lower end 17b. The upper end 17a and the lower end 17b may intersect to form a helical body having more than one spiral. The maximum number of possible revolutions of the central spindle 8 is limited by this intersection of the ends and the number of convolutions of the guide spring 12.

On one of its ends, here the lower end 17b, the slide ring 17 has a radially inwardly extending projection 18. As can be seen in fig. 2, the projection 18 extends in the hollow shaft 7. More precisely, the projection 18 of the slide ring 17 can be inserted or, in use, inserted into the longitudinal groove 11 of the hollow rod 7. This longitudinal groove 11 can be seen particularly clearly in fig. 8 and 9.

Fig. 8 shows the hollow rod 7 in a schematic view. The hollow rod 7 is configured as a hollow cylinder, which encloses a hollow rod interior 29. As shown in fig. 8, a hollow shaft bore 31 is provided in the upper region of the hollow shaft 7, through which the central spindle 8 can be guided. A longitudinal groove 11 is arranged on the circumferential surface 10, which groove extends in the axial direction (parallel to the axis of rotation R in the installed state). The longitudinal groove 11 is preferably open downward (i.e. to the underside 3). Alternatively, however, the longitudinal slot may be upwardly and downwardly restricted, as shown in fig. 9.

In the installed state, the projection 18 of the slide ring 17 is arranged in this longitudinal groove 11. Thereby, the slip ring 17 cannot rotate relative to the hollow rod 7. That is to say, the rotational security of the slip ring 17 is achieved by means of the longitudinal grooves 11 and the projections 18. The slide ring 17 can therefore only move axially upwards (along the longitudinal groove 11) and axially downwards (also along the longitudinal groove 11).

When the rotor 6 rotates in operation and the adapter element 13 transmits this rotational movement to the guide spring 12 (via the eccentric opening 13 c), the guide spring 12 rotates relative to the hollow rod 7 and also relative to a slide ring 17 which is axially fixed in the hollow rod 7 (i.e. in the longitudinal groove 11). However, by rotation of the guide spring 12, the slip ring 17 is energized to move in the thread 16 of the guide spring 12. Accordingly, the slip ring 17 moves upward and downward along the thread 16. As can be seen particularly clearly in fig. 9, a helically configured sliding ring 17 extends in the thread 16 of the guide spring 12.

The spindle-stop geometry of the invention is now configured such that the slide ring 17 can only be moved upward along the thread 16 to such an extent that the slide ring 17 rests with its upper end 17a against the first stop element 14 of the guide spring 12.

Whether the upper or lower end position of the central spindle 8 is determined depends on the pitch of the guide spring or the screw 12. The first stop element 14 serves to determine the upper end position of the central spindle 8 if the pitch of the spindle 8 is not equal to the pitch of the screw 12. If the spindle 8 and the screw 12 have the same screw direction, the first stop element 14 predetermines the lower end position of the central spindle 8. Preferably, the pitch of the central main shaft 8 is the same as the pitch of the central screw 12.

As soon as the slide ring 17 abuts against the first stop element 14, the guide spring 12 cannot rotate further in this rotational direction relative to the slide ring 17. More precisely, by blocking the guide spring 12, i.e. the guide spring 12 cannot rotate any further, since it is locked by the slip ring 17, the rotation of the adapter element member 13 is braked.

The braking force flow in this case flows from the longitudinal groove 11 of the hollow rod 7 onto the projection 18 of the slide ring 17 and from the projection 18 to the upper end 17a of the slide ring 17 onto the first stop element 14 of the guide spring 12 and from the first stop element 14 onto the eccentric opening 13c of the adapter element 13. Of course, a certain stretching of the individual elements may occur, which results in a damping of the braking force, which is entirely desirable. This is the case in particular at the lower stop point.

Fig. 9 shows the slip ring 17 at this lower stop point. As shown in fig. 9, the guide spring 12 is rotated relative to the slide ring 17 (and the hollow rod 7) to such an extent that the slide ring 17 moves to the lower end of the guide spring 12. There, the lower end 17b of the slide ring 17 comes into contact with the second stop element 15 of the guide spring 12. The brake fluid now extends from the longitudinal groove 11 of the hollow rod 7 to the lower end 17b of the slide ring 17 and from the lower end 17b of the slide ring 17 to the (lower) second stop element 15 of the guide spring 17. From this second stop element 15, the brake flow extends along the entire guide spring 12 up to the first stop element 14 and then up to the eccentric opening 13c of the adapter element 13.

In this case, unlike the upper stop, the brake force flow is formed along the entire guide spring 12. If the guide spring 12 is designed as a rigid spiral, no or only negligible damping of the braking force acting on the central spindle 8 occurs.

Depending on the pitch of the screw, the lower or upper end position of the spindle 8 is obtained when the first stop element 14 is in contact with the upper end 17a of the slide ring 17, and the upper or lower end position of the spindle 8 is obtained when the second stop element 15 is in contact with the lower end 17b (optionally together with the maximum torsion angle of the screw 12).

Fig. 10 to 13 show the force transmission from the spindle 8 to the sleeve element 21 or the valve needle 20. The central spindle 8 has a punch-like end region 22, which is formed at the lower end of the spindle 8.

This punch-like end region 22 is accommodated in the sleeve element 21. More precisely, the punch-like end region 22 is accommodated in an accommodation region 21a of the sleeve element 21. As shown in fig. 10, a pressure spring 24 and a force transmission element 23 are also arranged in the receiving region 21 a.

The compression spring 24 shown in an enlarged view in fig. 13 is in contact with the sleeve bottom 21b of the sleeve member 21. The pressure spring 24 is a cylindrical coil spring which is placed on the sleeve bottom 21b of the sleeve element 21 in a lower region.

As shown in fig. 12, the force transmission element 23 has a head region 23a and a shaft region 23b. The rod region 23b in turn has a peripheral surface 23c.

The rod region 23b may be arranged inside the pressure spring 24. In other words, the pressure spring 24 is supported inwardly by the peripheral surface 23c of the rod region 23b. The force transmission element 23 therefore also serves as a guide element for the pressure spring 24, wherein, in addition, a bending of the pressure spring 24 can also be prevented by the inner circumferential surface of the receiving region 21 a. Therefore, in general, the pressure spring 24 is supported by the accommodation area 21a and the accommodation area 21 a.

As can be seen in fig. 12, the force transmitting element 23 has a mushroom shape overall. This means that the head region 23a is partially spherical, for example hemispherical, and has a larger outer circumference than the shaft region 23b. In other words, the head region 23a is mushroom-shaped and the shaft region 23b is mushroom-shaped.

Since the head region 23a is formed to be wide, an abutment region is formed between the force transmission element 23 and the pressure spring 24. That is to say, the upper region of the pressure spring 24 can abut against the lower region of the head region 23 a.

However, the mushroom-head shape of the head region 23a also has the advantage that the contact region with the punch-like end region 22 is substantially point-like. Axial forces, that is to say from top (2) to bottom (3) or from bottom (3) to top (2), can be transmitted well through this point-like contact region, while torques are transmitted only very poorly. Thus, substantially no torque is transmitted from the punch-like end region 22 to the force transmission element 23. Therefore, the force transmitting element 23 can function as a kind of torque limiting mechanism.

When the rotational movement is transmitted from the rotor 6 via the adapter element 13 to the central spindle 8, the punch-like end region 22 moves upwards or downwards. When the punch-like end region 22 moves downward, it presses against the force transmission element 23, which in turn presses in a damped manner via the compression spring 24 against the sleeve bottom 21b and thus against the sleeve element 21 and the valve needle 20. This means that the valve needle 20 is pressed in the direction of the valve seat 34.

The upper region (towards the upper side 2) of the sleeve element 21 is closed off by a bushing 44. The bushing 44 is configured as a hollow cylinder and is made of a different material than the main shaft 8. In particular, the first material used to make the main shaft 8 is harder than the second material used to make the bushing 44. Thus, a low friction between the spindle 8, i.e. the punch-like end region 22, and the bushing 44 can be achieved. This is advantageous, whereby the valve needle 20 does not rotate together in the valve seat 34 for a long time.

This also means that, during the friction between the first material and the second material, a targeted wear occurs on the (less hard) second material. This makes it possible to control the wear of the force transmission means or of the components involved.

The bush 44, the sleeve element 21 with the valve needle 20 and the force transmission element 23 rotate at the same speed as the spindle 8 until the valve needle 20 is blocked in its axial movement in the valve seat 34 and the prevailing torque is smaller than between the contact positions of the bush 44 with the spindle 22. The valve needle 20 is only stopped when the damped torque (the traction torque) in the valve seat 34 is sufficiently large. From that point on, relative motion occurs between the main shaft 22 and the bushing 44. This relative movement takes place briefly at the end face (bush 44) and then only partially on the inner circumferential surface of the bush 44.

The main reason for the additional rotation of the spindle 8 after the valve needle 20 has been seated in the valve seat 34 is that a reliable closure is ensured even after a long operating time. Therefore, the valve should be reliably closed also after years of wear. Thus, the main shaft 8 is rotated in multiple steps, for example, 10 steps. This supplementary rotation requires a reliable torque decoupling.

The advantage in the use of the bushing 44 is, in particular, that it can be subjected to wear in a targeted manner and ensures low friction with respect to the main shaft 8. Neither the sleeve element 21 nor the (central) spindle 8 wear out.

Since the force transmission region between the force transmission element 23 and the central spindle 8 is kept as small as possible by the special shape of the head region 23a, no particularly high friction occurs here either, so that the force transmission element 23 can also be produced from the first material.

The first material is for example stainless steel and the second material is for example a copper alloy, preferably brass. The material pairing of brass and stainless steel is particularly advantageous. Since the sleeve element 44 is of relatively long construction in the longitudinal direction of extension (that is to say along the axis of rotation R), there is also sufficient material which can be removed from said sleeve element.

Fig. 14 shows a longitudinal section through the valve base body 5. The valve base 5 has a side portion 5a facing the housing 4, which is an upper side (facing the upper side 2) of the valve base 5. On the side opposite to the side 5a facing the housing 4, the valve base 5 has a side 5b facing away from the housing 4.

As shown in fig. 1, in a state of being mounted in the valve mounting space 43, the fluid inlet chamber 27 is configured adjacent to the side 5b of the valve base body 5 facing away from the housing 4.

The valve base body 5 further comprises a receiving region 33, as shown in fig. 1, in which (in the assembled state) the hollow shank 7 is first received and the sleeve element 21 is received within the hollow shank 7.

A circumferential undercut 32 is formed in the lower region of the receiving region 33.

The valve seat accommodation region 35 is arranged at a lower portion in the valve base body 5. The seat receiving area 35 provides a stop for the seat 34 when it is pushed into the valve base 5 from above. A reliable and defined fit of the valve seat 34 is thereby achieved.

A lower seal receiving region 36 is formed on the outer lower region of the valve base body 5. As shown in fig. 1, in the assembled state, an annular sealing body can be embedded in the lower seal receiving region. The annular sealing body seals the fluid inlet chamber 27 from the region of the fluid channel 46 which is arranged below the expansion valve 1 and vice versa.

Returning to fig. 14, an upper seal receiving area 37 is formed in the middle to upper area of the valve base body 5. As shown in fig. 1, in this upper seal receiving region 37, in the installed state, an annular sealing element is likewise arranged, which seals off the fluid inlet chamber 27 in particular from the outside environment.

Furthermore, as shown in fig. 14 to 16, a housing seat 39 is arranged on the upper side 2 of the valve base body 5. The housing seat is arranged, in particular, radially around the upper region of the valve base body 5 (on the side facing the housing 4) in such a way that it can receive the housing 4 in a sealed manner. As shown in fig. 1, the closing element (for example in the form of a ring) may press the housing 4 radially inwards from the outside towards the housing seat 39.

A plurality of

pressure equalization passages

25, 26 and 41 are configured within the expansion valve 1. Thus, a first pressure equalization channel 25 is arranged, which connects the housing inner chamber 28 with the fluid inlet chamber 27 in order to establish a pressure equalization between these two chambers.

The first pressure equalization channel 25 has a first channel area 25a and a second channel area 25b. As shown in fig. 14 and 16, a first passage area 25a is formed in the valve base body 5. In particular, the first passage area 25a is a bore which enters the valve base body 5 from the side 5b facing away from the housing 4. The first channel region 25a is designed to extend as far as the circumferential undercut 32 of the valve base body 5. This means that the hole extends all the way to the undercut 32. The first channel region 25a thus provides a connection from the side 5b facing away from the housing 4 to the receiving region 33 of the base body 5.

In the assembled state of the expansion valve 1, the hollow rod 7 shown in fig. 17 is accommodated in this accommodation region 33. The hollow bar 7 comprises a second channel region 25b, which extends upwards from its lower end in the form of a longitudinal slot 11.

Particularly preferably, the lower end of the hollow rod 7 is designed as a circumferential chamfer 38, so that both the circumferential chamfer 38 and the circumferential undercut 32 serve as a connecting region between the first channel region 25a and the second channel region 25b.

In general, a circumferentially surrounding connection region has the advantage, inter alia, that no alignment between the hollow rod 7 and the valve base body 5 is required. In principle, however, this would be sufficient if a circumferential undercut 32 or a circumferential chamfer 38 were formed. However, the formation of two elements results in a faster pressure equalization.

The longitudinal slot 11 of the hollow bar 7 thus has a double function. The longitudinal grooves serve here, on the one hand, for guiding the slide ring 17 and, on the other hand, for pressure compensation as the second passage area 25b. This is effected in particular in that the longitudinal grooves 11 open out into the housing interior 28. Thus creating a pressure balance between the fluid inlet chamber 27 and the housing internal chamber 28.

The second pressure equalization channel 26 provides for pressure equalization between the hollow shaft interior 29 and the housing interior 28. This second pressure equalization channel 26 can be seen particularly clearly in fig. 17. In this figure, it can be seen in particular that the second pressure equalization channel 26 is formed in the region of the maximum radial extent of the longitudinal groove 11 and of the hollow shaft interior 29. This has the particular advantage that the second pressure compensation channel 26 can also be produced simultaneously when the longitudinal groove 11 is introduced into the hollow shaft 7, which is designed as a hollow shaft interior 29, without a separate working step being required for this purpose.

In principle, the second pressure equalization channel 26 is an opening on the bottom of the longitudinal groove 11. This opening is connected to the hollow shaft interior 29 and the longitudinal groove 11 (and thus also to the housing interior 28). The second pressure compensation channel 26 is also formed in part by the second channel region 25b of the first pressure compensation channel 25, or a common region of the pressure compensation channels is used.

The expansion valve 1 also has a third pressure equalization channel 41. This third pressure compensation channel 41 is particularly clearly visible in fig. 10 and connects a lower inner region 42 of the valve base body 35 to the receiving region 21a of the sleeve element 21. The lower, inner region 42 of the valve base body 5 is also connected to the fluid inlet chamber 27 via a fluid opening 40, as can be seen in fig. 1.

All the features explained and illustrated in connection with the individual embodiments of the invention can be provided in different combinations in the subject matter according to the invention in order to achieve the advantageous effects of the features at the same time.

In particular, individual aspects of the expansion valve 1 have been described in the description. Various aspects may be claimed herein separately from other aspects.

List of reference numerals

1. Expansion valve

2. Upper side

3. Lower side

4. Shell body

5. Valve base

5a (of the valve base) side facing the housing

5b (of the valve base) side facing away from the housing

6. Rotor

7. Hollow rod

8. Central spindle

9. Screw connection

10 (hollow bar) surrounding surface

11. Longitudinal groove

12. Spiral body

13. Adapter element

13a plate-shaped basic area

13b accommodation area for central spindle

13c eccentric opening

13d center via

14. First stop element

15. Second stop element

16 Thread (of the guiding spring)

17. Slip ring

17a (of the slip ring) upper end

17b (of the slip ring)

18. Protrusion

20. Valve needle

21. Sleeve element

21a (of the sleeve element) receiving region

21b sleeve bottom

22. Punch-shaped end region

23. Force transmission element

23a head region

23b rod region

23c (of the rod region of the force transmission element)

24. Pressure spring

25. First pressure balance channel

25a (of the first pressure equalization channel) first channel region

25b (of the first pressure equalization channel) second channel region

26. Second pressure balance channel

27. Fluid inlet chamber

28. Inner cavity of shell

29. Hollow rod inner cavity

31. Hollow rod hole

32 Circumferential undercut (of the substrate)

33 (of the substrate) receiving area

34. Valve seat

35 Valve seat receiving area (of the base body)

36. Lower seal receiving area

37. Upper seal receiving area

38 Rounded chamfers (of hollow bars)

39. Shell seat

40. Fluid hole

41. Third pressure balance channel

42 Lower interior region (of valve base)

43. Valve installation space

44. Bush

46. Fluid channel

R axis of rotation.

Claims

1. An expansion valve (1) operable with a stepping motor for installation in a valve installation space (43), wherein the expansion valve (1) has:

a housing (4);

a hollow rod (7) arranged in the housing (4);

a valve base (5) carrying the hollow stem (7) and closing the housing (4);

a rotor (6) which can be driven by means of a stator; and

a central spindle (8) which is arranged inside the hollow rod (7) and can be driven by the rotor (6) such that a rotational movement of the central spindle (8) can be converted by means of a threaded connection (9) into an axial movement for opening and closing the expansion valve (1),

wherein the housing (4) and a side (5 a) of the valve base body (5) facing the housing (4) define a housing inner chamber (28),

wherein a hollow stem inner chamber (29) is formed inside the hollow stem (7), wherein a fluid inlet chamber (27) is arranged adjacent to a side (5 b) of the valve base body (5) facing away from the housing (4) in a state in which the expansion valve (1) is mounted in the valve mounting space (43),

wherein the housing interior (28) is connected to the fluid inlet chamber (27) for pressure equalization via a first pressure equalization channel (25),

wherein the first pressure compensation channel (25) has a first channel region (25 a) which is arranged at least partially in the valve base body (5) and a second channel region (25 b) which is arranged at least partially in the hollow shank (7),

wherein the first channel region (25 a) and the second channel region (25 b) are connected to one another by a circumferentially surrounding connecting region,

wherein the second channel region (25 b) is configured as a longitudinal groove (11) which, in the mounted state of the expansion valve (1) in the hollow rod (7), extends from a region arranged in the valve base body (5) to a region which is not arranged in the valve base body (5).

2. An expansion valve (1) according to claim 1,

wherein the circumferentially surrounding connecting region is a circumferential undercut (32) which is arranged on the inner circumference of a receiving region (33) of the valve base body (5).

3. An expansion valve (1) according to claim 1,

wherein the circumferentially surrounding connecting region is a circumferential chamfer (38) arranged on the outer circumference of the hollow rod (7).

4. An expansion valve (1) according to claim 2,

5. An expansion valve (1) according to any of claims 1-4,

wherein the expansion valve (1) has a second pressure equalization channel (26) for pressure equalization between the hollow shaft interior (29) and the housing interior (28), which second pressure equalization channel is formed at least partially by the second channel region (25 b).

6. An expansion valve (1) according to claim 1,

wherein a second pressure equalizing channel (26) is arranged in the region of the maximum radial extension of the longitudinal groove (11) and the hollow shaft interior (29).

7. An expansion valve (1) according to claim 5,

wherein the second pressure equalization channel (26) is arranged in the region of the longitudinal groove (11) and of the maximum radial extension of the hollow shaft interior (29).

8. An expansion valve (1) according to any of claims 1-4,

wherein the expansion valve (1) has an adapter element (13) arranged between the rotor (6) and the central main shaft (8) for transferring torque from the rotor (6) to the central main shaft (8); and is

Wherein the adapter element (13) has at least one eccentric opening (13 c) which is arranged in such a way that it balances the pressure in the housing interior (28) above the adapter element (13) and below the adapter element (13).

9. An expansion valve (1) according to any of claims 1-4,

wherein the expansion valve (1) has a third pressure compensation duct (41) which is arranged between a receiving region (21 a) of a sleeve element (21) having a valve needle (20) of the expansion valve (1) and a lower inner region (42) of the valve base body (5), in which the valve needle (20) is designed to be axially movable and which is connected to the fluid inlet chamber (27) via a fluid opening (40).

10. An expansion valve (1) according to claim 9,

wherein a punch-like end region (22) of the central spindle (8), a compression spring (24) and a force transmission element (23) are accommodated in an accommodation region (21 a) of the sleeve element (21).

11. An expansion valve (1) according to claim 10,

wherein the force transmission element (23) is configured and arranged such that it transmits an axial force from the central spindle (8) via the pressure spring (24) onto the sleeve element (21) by contact with the central spindle (8), wherein the force transmission element (23) is mushroom-shaped as seen in cross section.