Method for setting the opening pressure of a pressure relief valve during assembly, pressure relief valve produced by such a method, compressor in a refrigerant circuit comprising such a pressure relief valve, and refrigerant circuit comprising such a pressure relief valve

Abstract

The invention relates to a method for setting the opening pressure of a pressure relief valve (10) during assembly, the method comprising the following steps: - pre-assembling a valve body (14), a spring (18), and a spring retainer (20) in a main body (12); - inserting the spring retainer (20) into the main body (12) by means of an assembly tool; - applying a test pressure and determining whether the specified opening pressure has been reached; if this is not the case, repeating the preceding step; and - fixing the spring retainer (20) in the main body (12), thereby fixing the opening pressure of the pressure valve (10). The invention also relates to: a pressure relief valve (10) produced by such a method; a compressor in a refrigerant circuit comprising such a pressure relief valve (10); and a refrigerant circuit comprising such a pressure relief valve (10).

Description

[0001] Method for adjusting the opening pressure of a pressure relief valve during assembly and pressure relief valve manufactured according to such a method, compressor in a refrigerant circuit with such a pressure relief valve and refrigerant circuit with such a pressure relief valve

[0002] Description

[0003] The invention relates to a method for adjusting the opening pressure of a pressure relief valve during assembly, and to a pressure relief valve manufactured according to such a method. Furthermore, the invention relates to a refrigerant circuit with such a pressure relief 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 or pressure relief valves, represent a special subgroup. These protect system components from excessive pressure by opening when a threshold value, 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 reliability of a pressure relief valve is characterized by its ability to open at the specified opening pressure. Two methods are known in the art to ensure this. If no adjustment is possible after the valve has been installed, the components must be manufactured with high precision and tight tolerances. This results in comparatively high costs.

[0008] Alternatively, CN 110 762 263 A discloses, for example, an adjustment mechanism on the fully assembled valve. In this embodiment, the spring retainer is threaded into the base body and can thus be moved axially. Screwing it into the base body shortens the length of the pre-tensioned spring, thereby increasing its pre-tension and consequently the opening pressure. With this variant, the tolerances can be more generous. However, the additional threads on the base body and spring retainer require additional machining steps, which incurs additional costs.

[0009] In view of the aforementioned prior art, it is desirable to develop a pressure relief valve or a method for adjusting its opening pressure that requires neither additional work steps nor tight component tolerances. This is the object of the present invention. A further aspect of the present invention consists in the specification of a refrigerant circuit with a pressure relief valve manufactured according to such a method.

[0010] According to the invention, this problem is solved by a method according to claim 1. With regard to the valve, the problem is solved by an article according to claim 9, and with regard to the refrigerant circuit by an article according to claim 10.

[0011] A pressure relief valve described in the present application, hereinafter also referred to simply as a pressure valve or valve, comprises at least one base body, which functions as a valve housing. A valve body is arranged within the base body, which is configured and designed to close a valve opening provided in the base body and to allow fluid passage. A spring is provided adjacent to the valve body, which exerts a force on the valve body and thus defines the opening pressure of the pressure valve. For this purpose, the spring is supported by a spring retainer, which, in the assembled state of the pressure valve, is also arranged within the base body.

[0012] The first step, hereinafter referred to as step A, of the inventive method for setting the opening pressure of a pressure valve consists of pre-assembling the valve body, the spring, and the spring retainer in or on the base body. This method step can be performed upstream or directly at the station where at least the subsequent step is also carried out.

[0013] In the second step, hereinafter referred to as step B, the spring retainer is inserted into the base body using an assembly tool. This axial movement pre-tensions the spring located between the spring retainer and the valve body. The assembly tool is designed to achieve an advance in increments of a few tenths of a millimeter or continuously. Such fine increments are necessary because even a change in the installed length of the spring in the assembled state of just a few tenths of a millimeter has a significant effect on the pre-tension force and thus on the opening pressure of the pressure valve.

[0014] The third step of the process, hereinafter referred to as step C, involves applying a test pressure to the valve opening of the pressure relief valve. This determines whether the spring has been sufficiently pre-tensioned to achieve the specified opening pressure. If it is found that the specified opening pressure has not been reached, the second step is repeated. This is done until it has been determined that the specified opening pressure has been achieved.

[0015] Once this has been done, the spring retainer is fixed in the base body in the fourth step, hereinafter referred to as step D, thus securing it against axial displacement. This also fixes the installation length of the spring and the resulting preload force, which defines the opening pressure of the pressure valve.

[0016] The method described above works on the principle of adjusting the opening pressure of the pressure relief valve during its assembly. This allows geometric deviations of individual components to be compensated for during assembly. Conversely, the required tolerances of the individual components can be reduced, thus simplifying their manufacture.

[0017] In some embodiments of the pressure valve, particularly those with a ball as the valve body, a spring retainer may be provided as an additional component. This ensures a reliable seating of the valve body in the base body and reliable force transmission from the spring to the valve body and vice versa. The spring retainer is also inserted into the base body in step A, after the valve body and before the spring, and is therefore also part of the pre-assembly.

[0018] As described above, steps B and C can be performed sequentially or alternately until the specified opening pressure is reached. Steps B and C can be carried out at different stations. However, it is advantageous to perform steps B and C at a combined assembly / testing station to avoid time loss due to potentially multiple station changes.

[0019] If a combined assembly / testing station is available, it is advisable to perform steps B and C simultaneously. During the continuous or incremental insertion of the spring retainer by the assembly tool, a test pressure is applied to the valve opening of the base body continuously or at defined intervals. As soon as it has been determined that the specified opening pressure has been reached, the feed of the assembly tool is stopped and step D is proceeded.

[0020] The assembly tool can be either force-controlled or displacement-controlled. With a displacement-controlled tool, the feed occurs either at a continuous rate or in defined feed intervals. If a tool with defined feed intervals is used, these intervals must be sufficiently small, or it must be taken into account that even a feed of a few tenths of a millimeter has a significant impact on the preload force and thus on the opening pressure of the pressure relief valve. When using a displacement-controlled tool, the spring counterhold is inserted depending on the opposing test pressure. This allows for direct adjustment of the opening pressure of the pressure relief valve.

[0021] A force-controlled assembly tool is particularly suitable when using a combined assembly / testing station. The assembly tool can be configured to advance the spring-loaded counterholder into the base body until an opposing axial force, corresponding to the predefined opening pressure, is encountered. The predefined opening pressure is therefore set indirectly. If the assembly tool or its control system detects that the opposing axial force equals the predefined opening pressure, it stops the advance.

[0022] In step D, the spring retainer is fixed in the base body to prevent axial displacement of the spring retainer within the base body and thus a change in the opening pressure of the pressure valve. Several fixing methods are possible. For example, a friction-fit and / or positive-fit connection can be established between the spring retainer and the base body. One possibility is the local deformation of a radially outer section of the spring retainer, whereby it is pressed into an existing notch or groove in the base body, or one created during this step. Preferably, a retainer is provided on an outer side of the base body to hold it in position against the direction of deformation.

[0023] Likewise, fixation in the opposite direction is possible, i.e. by deforming a part of the base body, whereby this is pressed into an existing notch or groove on the radially outer side of the spring retainer, or one created in this step.

[0024] Instead of a force-fit and / or form-fit connection, a material-fit connection can also be created between the spring retainer and the base body. A welded joint, in particular a spot weld, serves as an example of this.

[0025] Regardless of the type of connection, when fixing the spring retainer in the base body, care must be taken to ensure that, if the connection is not made over the entire circumference, sufficient connection points are provided distributed around the circumference to guarantee the required axial securing.

[0026] A pressure relief valve manufactured according to one of the methods described above, which is also the subject of the present application, is characterized by the fact that it can be manufactured from components with larger tolerances, which are correspondingly easier to produce, and yet still exhibits a high degree of reliability with regard to the opening pressure.

[0027] 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.

[0028] 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.

[0029] The invention is explained in more detail below with reference to the single drawing. This drawing shows:

[0030] Fig. 1 shows a preferred first embodiment of a method according to the invention with a pressure relief valve according to the invention in a sectional view; Fig. 2 shows a preferred second embodiment of a method according to the invention with a pressure relief valve according to the invention in a sectional view;

[0031] Fig. 3 shows a first embodiment of a compressor according to the invention in a sectional view;

[0032] Fig. 4 shows a second embodiment of a compressor according to the invention in a sectional view; and

[0033] Fig. 5 shows a schematic view of an embodiment of a refrigerant circuit according to the invention.

[0034] Fig. 1 shows a pressure relief valve 10. This comprises a base body 12 which functions as a valve housing. In a first step A, which according to the illustration of Fig. 1 has already been completed, a valve body 14, a spring holder 16, a spring 18 and a spring retainer 20 were pre-assembled in the base body 12.

[0035] The spring retainer 20 is then inserted into the base body 12 using an assembly tool, the feed direction M of which is indicated by an arrow in Fig. 1. This causes the spring 18 arranged between the spring holder 16 and the spring retainer 20 to be pre-tensioned, which in turn determines the opening pressure of the pressure valve 10.

[0036] To determine whether the specified opening pressure has been reached, a test pressure p is applied to the valve opening provided in the base body 12. If the procedure is carried out in a combined assembly / testing station, the insertion of the spring retainer 20 and the application of the test pressure can be performed simultaneously. During insertion, which can be carried out either at a continuous feed rate or at defined feed intervals, the preload force of the spring 18 is increased until it is determined, based on the applied test pressure, that the specified opening pressure has been reached.

[0037] Once this has occurred, the advance of the assembly tool is stopped, with the assembly tool holding the spring retainer 20 in its current position. The spring retainer 20 is then fixed in the base body 12. In the embodiment shown in Fig. 1, this is achieved by means of a frictional and positive locking connection. A pair of pliers with a forming die 26 moves from the outside towards a circumferential groove 22 of the base body 12. Several notches 24 are provided in the radially outer region of the spring retainer 20, evenly distributed around its circumference. The circle around the reference numeral 24 in Fig. 1 does not denote a component, but merely represents a graphical cutout to make the reference numeral 24 legible. When actuated, the pliers 26 press corresponding sections of the base body 12 into the notches 24. This results in radial compression with simultaneous forming.In this way, the spring retainer 20 is secured against axial displacement within the base body 12, which also fixes the installation length of the spring 18 and sets the predetermined opening pressure of the pressure valve 10.

[0038] Fig. 2 shows a second preferred embodiment of a pressure relief valve 10 according to the invention. This differs from the pressure relief valve 10 according to Fig. 1 in that it does not include a spring retainer 16. Instead, the spring 18 is in direct contact with the valve body 14.

[0039] The spring retainer 18 is fixed in the base body 12 by a frictional and positive locking connection. Several notches 24 are provided around the circumference of an inner surface of the base body 12. In Fig. 2, the circle around reference numeral 24 does not denote a component but is a graphical cutout for the sake of readability. While a retainer 28 positioned on an outer surface of the base body 12 prevents radial displacement of the pressure relief valve 10, a tool with a forming die 26 moves axially into the spring retainer 18. The tool 26 then moves radially outward, pressing a corresponding section of the spring retainer 18 into the notches 24. This forming action creates a frictional and positive locking connection, securing the spring retainer 18 against axial displacement in the base body 12.

[0040] Fig. 3 shows a first embodiment of a compressor 30 according to the invention with a low-pressure side 32 and a high-pressure side 34. In the illustrated embodiment, the pressure relief valve 10 is arranged on the low-pressure side 32 of the compressor 30.

[0041] In contrast, Fig. 4 shows a second embodiment of an otherwise identical compressor 10, which differs from the embodiment shown in Fig. 3 in that the pressure relief valve 10 is arranged on the high pressure side 34.

[0042] Fig. 5 shows a schematic representation of a refrigerant circuit 36 ​​according to the invention. In addition to the compressor 30, the refrigerant circuit 36 ​​comprises a condenser 38, an expansion valve 40, and an evaporator 42. A refrigerant flows through the refrigerant circuit 36 ​​in a flow direction 44 indicated by arrows. In the illustrated embodiment, the pressure relief valve 10 is arranged downstream of the compressor 30 and upstream of the condenser 38 in the flow direction 44. However, embodiments are also conceivable in which the pressure relief valve 10 is arranged at other positions within the refrigerant circuit 36, e.g., downstream of the evaporator 42 and upstream of the compressor 30.

[0043] List of reference signs

[0044] 10 Pressure valve

[0045] 12 basic shapes

[0046] 14 valve bodies

[0047] 16 spring holders

[0048] 18 springs

[0049] 20 spring retainers

[0050] 22 Circumferential groove

[0051] 24 notch

[0052] 26 Pliers with forming die

[0053] 28 Counterholds

[0054] 30 compressors

[0055] 32 Low-pressure side

[0056] 34 High-pressure side

[0057] 36 Refrigerant circuit

[0058] 38 Capacitor

[0059] 40 Expansion valve

[0060] 42 evaporators

[0061] 44 Flow direction

Claims

Claims 1. Method for adjusting the opening pressure of a pressure relief valve (10) during assembly, wherein the pressure relief valve (10) comprises at least: a base body (12), a valve body (14), a spring (18) and a spring retainer (20), comprising the steps: Pre-assembly of the valve body (14), the spring (18) and the spring retainer (20) in the base body (12); Inserting the spring retainer (20) into the base body (12) using an assembly tool; Apply a test pressure and determine whether a specified opening pressure is reached; if not, repeat step B; and Fixing the spring counterholder (20) in the base body (12).

2. The method of claim 1, wherein the pressure relief valve (10) has a The spring holder (16) is arranged between the valve body (14) and the spring (18), and the spring holder (16) is also pre-assembled in the base body (12) in step A.

3. The method of claim 1 or 2, wherein steps B and C are carried out simultaneously or sequentially.

4. Method according to one of claims 1 to 3, wherein the assembly tool is a force-controlled tool which introduces the spring counterholder (20) into the base body (12) depending on an opposing axial force and thus indirectly sets the predetermined opening pressure.

5. Method according to one of claims 1 to 3, wherein the assembly tool is a displacement-controlled tool which inserts the spring counterholder (20) into the base body (12) depending on the opposing test pressure and thus directly sets the predetermined opening pressure.

6. Method according to any one of claims 1 to 5, wherein in step D a force-fit and / or form-fit connection is established between spring counterholder (20) and base body (12) by a The radial outer section of the spring retainer (20) is formed radially outwards into one or more notches or grooves of the base body (12) which were created before this step or are created in this step.

7. Method according to any one of claims 1 to 5 wherein in step D a force-locking and / or form-locking connection between spring counterholder (20) and base body (12) is produced by forming one or more sections of the base body (12) radially inwards into one or more notches or grooves of the spring counterholder (20) which were produced before this step or are produced in this step.

8. Method according to one of claims 1 to 5, wherein in step D a material-bonded connection is made between spring counterholder (20) and base body (12).

9. Pressure relief valve (10) whose opening pressure is set according to a method according to one of claims 1 to 8.

10. Compressor (30) in a refrigerant circuit (36) with a Overpressure valve (10) according to claim 9, wherein the overpressure valve (10) is arranged on the high pressure side (34) or on the low pressure side (32) of the compressor (30).

11. Refrigerant circuit (36) with a pressure relief valve (10) according to claim 9, wherein the pressure relief valve (10) is arranged in a flow direction (44) of the refrigerant circuit upstream or downstream of a compressor (30).

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