Pressure relief valve, compressor in a refrigerant circuit comprising such a pressure relief valve, refrigerant circuit comprising such a pressure relief valve, and method for assembling the pressure relief valve

Abstract

The invention relates to a pressure relief valve (10) comprising: a main body (12); a valve element (14); a spring retainer (16), the valve element (14) and the spring retainer (16) being arranged within the main body (12); and a helical spring (18) which is arranged at least partially between the valve element (14) and the spring retainer (16) and has an unground first spring end (20) and an unground second spring end (22). In order to save machining steps and to ensure optimum orthogonality between the axial spring ends (20, 22) and a spring axis (36), spring-end recesses (24) for receiving the first spring end (20) and / or the second spring end (22) are provided on the valve element (14) and / or on the spring retainer (16). The invention also relates to: a compressor comprising such a pressure relief valve; a refrigerant circuit comprising such a pressure relief valve; and a method for assembling such a pressure relief valve (10).

Description

[0001] Pressure relief valve, compressor in a refrigerant circuit with such a pressure relief valve, refrigerant circuit with such a pressure relief valve and method for mounting the pressure relief valve

[0002] Description

[0003] The invention relates to a valve according to the preamble of claim 1. Such a valve is known, for example, from EP 3 205 912 Al. Furthermore, the invention relates to a pressure relief valve, a refrigerant circuit, and a method for assembling such a valve.

[0004] Valves are used to control the flow of fluids in a system. They enable the precise regulation, opening, and closing of lines to achieve a desired operating state. Valves are used in both simple and complex applications to ensure the safety, efficiency, and reliability of systems.

[0005] Pressure relief valves, also known as overpressure valves, represent a special subgroup. These protect system components from excessive pressure by opening when a threshold, called the opening pressure, is reached, releasing the fluid, for example, into the environment. After sufficient fluid has been released and the pressure has fallen below the opening pressure, the overpressure valve closes, returning the system to its normal operating state.

[0006] Spring-loaded pressure relief valves are used in many applications, such as refrigerant circuits. They are employed to protect other components of the refrigerant circuit, particularly the condenser and expansion valve, from excessively high pressures. The force required to close the valve body is generated by a spring. The spring's preload determines the opening pressure of the pressure relief valve. The most common design uses a coil spring.

[0007] The aforementioned EP 3 205 912 Al shows a spring-loaded pressure relief valve, referred to in this case as a drain valve, with a helical spring. The axial ends of the helical spring rest on planar surfaces of the valve body and the spring retainer, respectively. However, due to the spiral shape and the simultaneously round cross-sectional geometry of the spring band, the axial ends of the spring are not planar. In the uncompressed state, the spring has only point contact with the valve body and the spring retainer. In the compressed state, the contact area increases, but at the expense of bending or twisting of the spring. In this case, the axial spring ends are no longer orthogonal to the spring axis.This can impair the reliability of the pressure relief valve, i.e., its opening at the desired opening pressure, and can also adversely affect the service life of the spring and thus the pressure relief valve.

[0008] To overcome these disadvantages, some designs use ground spring ends. An example of this is disclosed in CN 110 762 263 A. The aim of grinding the spring ends is to achieve the flattest possible axial spring end and thus the largest possible contact area with the planar mating surfaces of the valve body or the spring retainer. This improves the spring's resistance to bending or twisting, but does not completely eliminate the aforementioned disadvantages. This is not possible because, due to the geometry, a completely circumferential contact between the spring ends and the mating surfaces of the valve body or the spring retainer cannot be achieved. Furthermore, the additional machining step is disadvantageous in terms of the manufacturing process and costs.

[0009] The invention is therefore based on the objective of providing a valve that includes unground spring ends and simultaneously ensures the best possible orthogonality between the axial spring ends and the spring axis. Furthermore, one aspect of the invention is to provide a refrigerant circuit with such a valve. Another aspect of the invention is to provide a method for assembling such a valve. This objective is achieved by a valve with a base body within which a valve body, a spring retainer, and a helical spring, hereinafter also referred to simply as the spring, are arranged. The spring has unground spring ends and is at least partially arranged between the valve body and the spring retainer. The latter is understood to mean that the valve body and the spring retainer are spaced apart from each other, and this space is bridged by the spring.However, embodiments are also conceivable and described later in which individual sections of the valve body and / or the spring retainer extend into a space surrounded by the spring. "Unpolished spring ends" means that the cross-sectional geometry of the spring band remains essentially constant to its end; in particular, there is no tapering towards the ends of the spring band.

[0010] The valve is characterized by the inclusion of spring end recesses on the valve body and / or the spring retainer. These recesses are designed and configured to correspond to the respective unground spring end. In other words, the spring end recesses are shaped so that the corresponding spring end can fit into them; the recesses thus represent the negative of the associated spring end. It is advantageous to incorporate the geometry of the spring end recesses, or their negative form, directly into the tooling for the valve body or the spring retainer. This allows for the production of the components, including the spring end recesses, typically in a sintering process, without the need for subsequent mechanical machining.

[0011] The geometry of the spring end recess is selected such that the spring axis rests orthogonally on the respective contact surface of the valve body or spring retainer, even under load. Due to the full-surface contact of the spring with the valve body or spring retainer, the spring experiences no bending stress, either under preload or within the valve's operating range. This increases the reliability of the valve's correct opening and extends its service life. Compared to prior art designs with ground spring ends, the invention has the advantage that the additional grinding step in spring manufacturing is eliminated. Furthermore, a ground spring end, due to its reduced cross-section, always represents a mechanical weak point, which has been eliminated in the present invention.

[0012] In order to achieve the best possible fit of the first spring end in the spring end recess of the valve body and / or the second spring end in the spring end recess of the spring retainer, the spring end recesses are preferably designed so that their diameter corresponds to the diameter of the coil spring and their widths and cross-sectional geometries correspond to those of the spring end of the coil spring which comes into contact with them.

[0013] According to a further preferred embodiment, the slope of the spring end recess of the valve body corresponds to an outermost slope of the first spring end and / or the slope of the spring end recess of the spring retainer corresponds to an outermost slope of the second spring end. This design ensures that the desired orthogonality between the spring axis and the respective contact surface is maintained even when the spring is under tension.

[0014] Depending on the application-specific requirements, the valve body can be designed as a single piece or in multiple parts, according to preferred embodiments. When using a ball as the valve body, providing a spring end recess can be challenging. In this case, an intermediate piece is advantageous, which on the one hand corresponds to the ball and on the other hand has a contact surface with a spring end recess. In the present application, this intermediate piece is also incorporated into the valve body. The multi-part design of the valve body can offer cost advantages, as components with simpler geometries may be used.

[0015] A one-piece valve body design results in a more complex geometry. While the sealing surface of the valve body requires a low tolerance for surface roughness, the spring end recess must be incorporated on the opposite section. A one-piece valve body design is advantageous when weight reduction and / or the use of a reduced number of components are paramount.

[0016] According to a further preferred embodiment, the valve body and / or the spring retainer have a guide pin which is designed and configured to extend into the space enclosed by the spring. Conical guide pins are particularly preferred. Such a design has no influence on the valve's operation but facilitates assembly as described below.

[0017] A pressure relief valve in one of the embodiments described above can be used in a compressor within a refrigerant circuit. It can be arranged on either the low-pressure or high-pressure side to protect the other components of the refrigerant circuit from excessively high pressures.

[0018] Alternatively or additionally, a pressure relief valve can be used in a refrigerant circuit in one of the embodiments described above. There, it is arranged upstream or downstream of the refrigerant compressor, thereby protecting the other components of the refrigerant circuit, in particular the condenser and the expansion valve, from excessively high pressures.

[0019] The remaining aspect is addressed by a procedure with the following steps. First, the valve body is inserted into the base body, which serves as the valve housing, until the sealing surface of the valve body is in contact with the corresponding sealing surface of the base body. Next, the coil spring is inserted into the base body and one end of the spring is placed onto the valve body. If the valve body has a guide pin, this step is facilitated by guiding the spring into the desired position on the valve body. In the next step, the spring retainer is placed onto the other end of the spring, which at this point may still be located outside the base body. If the spring retainer has a guide cone, this is inserted into the space enclosed by the spring.The spring retainer is then inserted into the base body, thereby tensioning the spring. This linear movement is accompanied by a rotation of the spring retainer around the spring axis.

[0020] In principle, both directions of rotation are conceivable and possible in this process step. However, a direction of rotation, viewed in the insertion direction of the spring retainer, which corresponds to the winding direction of the helical spring, is particularly preferred. Therefore, for a right-handed helical spring, the rotation is clockwise, while for a left-handed helical spring, it is counterclockwise.

[0021] In embodiments with spring end recesses on the valve body and the spring retainer, the rotation of the spring retainer during its insertion into the base body initially causes the second spring end to contact an end face of the spring end recess on the spring retainer. This then acts as a driver and ensures that the spring also rotates around its axis until the first spring end contacts an end face of the spring end recess on the valve body.

[0022] In the final step of the process, the spring retainer is fixed in the base body. The axial position of the spring retainer at the end of this step determines the spring preload and thus ultimately the valve opening pressure.

[0023] According to a preferred embodiment of the method, the spring retainer describes a rotation angle of at least 360° during insertion. This ensures that, regardless of the initial position of the valve body, spring, and spring retainer, the spring ends come into complete contact with the spring end recesses of the valve body and / or the spring retainer. The invention is explained in more detail below with reference to the accompanying drawings. The embodiment shown therein represents an example of how the valve according to the invention can be designed.

[0024] These show,

[0025] Fig. 1 shows a preferred first embodiment of the valve according to the invention in a sectional view;

[0026] Fig. 2 shows a valve body according to the first embodiment of the invention in a perspective view;

[0027] Fig. 3 shows a spring counterholder according to the first embodiment of the invention in a perspective view;

[0028] Fig. 4 shows a schematic representation of the assembly process;

[0029] Fig. 5 shows a first embodiment of a compressor according to the invention in a sectional view;

[0030] Fig. 6 shows a second embodiment of a compressor according to the invention in a sectional view; and

[0031] Fig. 7 shows a schematic view of an embodiment of a refrigerant circuit according to the invention.

[0032] In the following description and in the figures, the same reference symbols are used for identical parts.

[0033] Fig. 1 shows a preferred embodiment of the pressure relief valve 10 according to the invention. The valve 10 comprises a base body 12, which functions as a valve housing. A valve body 14 is arranged within the base body 12, which is configured and designed to close and open a valve opening 38. A guide pin 32 is formed at its end facing away from the valve opening 38. In the viewing direction according to Fig. 1, a spring retainer 16 is arranged above the valve body 14 and, in the assembled state, also within the base body 12. As its name suggests, the spring retainer 16 is configured and designed to support a coil spring 18. For this purpose, the spring retainer 16 is fixed axially, i.e., in the direction of a spring axis 36, in the base body 12. A guide pin 34 is also formed on its side facing the valve body 14.

[0034] The guide pins 32, 34 serve to guide the helical spring 18. In the embodiment shown in Fig. 1, the guide pins 32, 34 are located within the space enclosed by the helical spring 18; the helical spring 18 is thus guided internally. The guide pins 32, 34 support the helical spring 18 and thus counteract axial buckling. They also simplify assembly as described later.

[0035] The coil spring 18 is located at least partially between the valve body 14 and the spring retainer 16. It has unground spring ends 20 and 22, with the first spring end 20 facing the valve body 14 and the second spring end 22 facing the spring retainer 16. When the pressure relief valve 10 is installed, the coil spring 18 is under preload. This preload defines the opening pressure of the valve 10. For the valve 10 to open as precisely as possible, i.e., when the opening pressure is actually applied, it is crucial that the coil spring 18 is aligned straight in its preloaded state. This means that the coil spring 18 is neither bent nor twisted, but rather that its spring axis 36 is as coaxial as possible with an imaginary valve axis.

[0036] To achieve this, spring end recesses 24 and 26 are provided at the opposing ends of the valve body 14 and the spring retainer 16. These recesses are negatively shaped to the unground spring ends 20 and 22. In the assembled state, the spring ends 20 and 22 rest in the spring end recesses 24 and 26. This design allows for maximum contact area between the spring ends 20 and 22 and their corresponding counterparts, ensuring an undistorted and unwound alignment of the helical spring 18 even when (pre-)tensioned. Fig. 2 shows a perspective view of the valve body 14. The spring end recess 24 is located below the guide pin 32. Its diameter corresponds to the diameter of the helical spring 18. The slope of the spring end recess 24 corresponds to that of the outermost slope of the first spring end 20 of the helical spring 18.This design allows the coil spring 18 to come fully into contact with the spring end recess 24 with its first spring end 20.

[0037] The design and function of the spring end recess 26 on the spring retainer 16 shown in Fig. 3 follow the same principle. Here, too, the spring end recess 26 is arranged below the guide pin 34, although in the view shown in Fig. 1, the spring end recess 26 is located above the guide pin 34. The diameter of the spring end recess 26 of the spring retainer 16 also corresponds to the diameter of the coil spring 18, as do the width and cross-sectional geometry of the spring end recess 26 and the width and cross-sectional geometry of the second spring end 22. Furthermore, the slope of the spring end recess 26 corresponds to that of the outermost slope of the second spring end 22 of the coil spring 18. Analogous to the design of the spring end recess 26 of the valve body 14, this ensures that the coil spring 18 can come into complete contact with its second spring end 22 in the spring end recess 26.

[0038] The inventive method for mounting a valve 10 is explained again with reference to Figures 1 and 4. In the first step, the valve body 14 is inserted into the base body 12, which is preferably positioned vertically, i.e., according to the orientation shown in Figure 1, until the sealing surface of the valve body 14 comes into contact with the sealing surface of the base body 14. The helical spring 18 is then inserted into the base body 12 and its first spring end 20 is placed onto the valve body 14, with the guide pin 32 facilitating positioning. At the end of this step, the second spring end 22 of the uncompressed helical spring 18 typically projects beyond the upper edge of the base body 12.

[0039] In the next step, the spring retainer 16 is placed onto this second spring end 22 by inserting the guide pin 34 into the space surrounded by the coil spring 18. At this point, neither the first spring end 20 nor the second spring end 22 necessarily rests against their respective corresponding spring end recesses 24, 26.

[0040] The spring retainer 16 is then inserted into the base body 12, thereby pre-tensioning the helical spring 18. This is symbolized in Fig. 4 by the vertical arrow. The linear movement of the spring retainer 16 is accompanied by a rotation about the spring axis 30, also represented by an arrow in Fig. 4. This rotation preferably occurs in the direction corresponding to the winding direction of the helical spring 18. At the beginning of the rotation, the spring retainer 16 rotates on the second spring end 22 until the second spring end 22 comes to rest against the end face 30 of the spring end recess 26 of the spring retainer 16. As the rotation continues, the end face 30 of the spring end recess 26 of the spring retainer 16 acts as a driver, causing the helical spring 18 to also rotate about the spring axis 36.This rotation brings the first spring end 20 into contact with the end face 28 of the spring end recess 24 of the valve body 14 and the coil spring 18 is fixed in its desired orientation.

[0041] Once the spring retainer 16 has reached the predetermined axial position, which corresponds to a specific opening pressure of the valve 10, it is fixed in the base body 12. The assembly of the valve 10 is thus complete.

[0042] Fig. 5 shows a first embodiment of a compressor 40 according to the invention with a low-pressure side 42 and a high-pressure side 44. In the illustrated embodiment, the pressure relief valve 10 is arranged on the low-pressure side 42 of the compressor 40.

[0043] In contrast, Fig. 6 shows a second embodiment of an otherwise identical compressor 10, which differs from the embodiment shown in Fig. 5 in that the pressure relief valve 10 is arranged on the high pressure side 44.

[0044] Fig. 7 shows a schematic representation of a refrigerant circuit 46 according to the invention. In addition to the compressor 40, the refrigerant circuit 46 comprises a condenser 48, an expansion valve 50, and an evaporator 52. A refrigerant flows through the refrigerant circuit 46 in a flow direction 54 indicated by arrows. In the illustrated embodiment, the pressure relief valve 10 is arranged downstream of the compressor 40 and upstream of the condenser 48 in the flow direction 54. However, embodiments are also conceivable in which the pressure relief valve 10 is arranged at other positions within the refrigerant circuit 46, e.g., downstream of the evaporator 52 and upstream of the compressor 40.

[0045] List of reference signs

[0046] Overpressure valve

[0047] basic body

[0048] Valve body

[0049] Spring counter holder

[0050] coil spring

[0051] First spring end

[0052] Second spring end

[0053] Spring end recess of the valve body

[0054] Spring end recess of the spring retainer

[0055] Front surface of the spring end recess of the valve body

[0056] Front surface of the spring end recess of the spring retainer

[0057] Guide pin

[0058] Guide pin

[0059] Spring axle

[0060] Valve opening

[0061] compressor

[0062] Low-pressure side

[0063] High pressure side

[0064] Refrigerant circuit

[0065] capacitor

[0066] Expansion valve

[0067] Evaporator

[0068] Flow direction

Claims

Claims 1. Pressure relief valve (10), with - a basic body (12), - a valve body (14), - a spring retainer (16), wherein the valve body (14) and the spring retainer (16) are arranged inside the base body (12), and - a coil spring (18) which is at least partially arranged between the valve body (14) and the spring retainer (16) and has an unpolished first spring end (20) and an unpolished second spring end (22), which is indicated by the fact that spring end recesses (24, 26) are provided on the valve body (14) and / or on the spring retainer (16) for receiving the first spring end (20) and / or the second spring end (22).

2. Pressure relief valve (10) according to claim 1, which is characterized by the fact that a diameter of the spring end recess (24) of the valve body (14) and / or of the spring end recess (26) of the spring retainer (16) corresponds to a diameter of the coil spring (18).

3. Pressure relief valve (10) according to claim 1 or 2, characterized by the fact that a slope of the spring end recess (24) of the valve body (14) corresponds to an outermost slope of the first spring end (20) and / or a slope of the spring end recess (26) of the spring retainer (16) corresponds to an outermost slope of the second spring end (22).

4. Pressure relief valve (10) according to one of claims 1 to 3, wherein the valve body (14) is made in one piece or in multiple pieces.

5. Overpressure valve (10) according to one of claims 1 to 4, wherein the valve body (14) and / or the spring retainer (16) have a guide mandrel (32, 34), preferably a conical guide mandrel.

6. Compressor (40) in a refrigerant circuit (46) with a pressure relief valve (10) according to one of claims 1 to 5, wherein the pressure relief valve (10) is arranged on the high pressure side (44) or on the low pressure side (42) of the compressor (40).

7. Refrigerant circuit (46) with a pressure relief valve (10) according to one of claims 1 to 5, wherein the pressure relief valve (10) is arranged in a flow direction (54) of the refrigerant circuit (46) upstream or downstream of a compressor (40).

8. Method for assembling a pressure relief valve (10) according to one of claims 1 to 5, comprising the steps: - Inserting the valve body (14) into the base body (12), - Inserting the coil spring (18) into the base body (12) and placing the first end (20) of the coil spring (18) onto the valve body (14) or its guide pin (26), - Placing the spring retainer (16) or its guide pin (28) on the second spring end (22) of the coil spring (18), and - Inserting the spring counterholder (16) into the base body (12) while rotating it about a spring axis (30), and - Fixing the spring counterholder (16) in the base body (12).

9. Method according to claim 8, wherein the rotation of the spring counterholder (16) about the spring axis (30) is clockwise if the coil spring (18) is right-handed, and counterclockwise if the coil spring (18) is left-handed. 15 10. Method according to claim 8 or 9, wherein an end face (30) of the spring end recess (26) of the spring counterholder (16) acts as a driver for the second spring end (22) of the coil spring (18) and transmits the rotation of the spring counterholder (16) into a rotation of the coil spring (18) about the spring axis (36).

11. Method according to one of claims 8 to 10, wherein the first spring end (20) of the coil spring (18) comes into contact with an end face (28) of the spring end recess (24) of the valve body (14).

12. Method according to any one of claims 8 to 11, wherein the rotation of the spring counterholder (16) during insertion into the base body (12) describes an angle of at least 360°.

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