Radial piston compressor

Abstract

The invention relates to a radial piston compressor, comprising a compressor unit (1) and a drive device (2) for driving the compressor unit (1), wherein the compressor unit (1) comprises a plurality of piston-working-chamber assemblies (13), which are arranged radially around an eccentric shaft (11, 12), the eccentric shaft being driven by the drive device (2); each piston-cylinder-bore assembly (13) comprises a piston (132), which can be moved in a working chamber (131); and an inlet valve cover (15) with an inlet valve (24) is provided on the head-side of the working chamber (131), the inlet valve (24) comprising a fluid inlet channel (241) in the inlet valve cover (15) and a valve sheet (242) with a valve tongue (2421), which is designed to selectively close or release the fluid inlet channel (241) and is connected to the valve sheet (242) via two valve feet (2422), the valve feet (2422) having an outwardly curved design and tapering in the direction of the valve tongue (2421).

Description

[0001] radial piston compressor

[0002] The present invention relates to a radial piston compressor according to the preamble of claim 1.

[0003] A radial piston compressor is a fluid power component. In contrast to an axial piston compressor, in this type of compressor at least one piston-working chamber assembly is arranged radially and perpendicular to the drive shaft. A radial piston compressor can also be referred to as a compressor based on the radial piston principle.

[0004] The piston's conveying or reciprocating motion is usually generated by an eccentric. Therefore, the drive shaft with the eccentric can also be referred to as an eccentric shaft. A radial piston compressor typically comprises several piston-working chamber assemblies that extend radially from the eccentric shaft in a star-shaped pattern.

[0005] A piston-work chamber assembly essentially comprises a working chamber, also called a cylinder, and a piston that moves up and down within the working chamber. The piston has a central geometric axis that coincides with the piston's direction of movement. In a radial piston compressor with an eccentric shaft, the piston has a contact surface on its side facing the eccentric shaft. The eccentric disk contacts this surface during the rotation of the eccentric shaft. The eccentric shaft has an axis of rotation around which it rotates. When the eccentric disk contacts the contact surface, the piston moves upward, compressing the medium in the working chamber.

[0006] Radial piston compressors are used, for example, to compress refrigerant in the air conditioning systems of motor vehicles, especially in electric vehicles. A refrigerant such as CO2 can be used as the medium to be compressed. However, other media and refrigerants are also conceivable.

[0007] A radial piston compressor of the aforementioned type is known, for example, from DE 10 2020 211 680 Al or DE 10 2022 133 723 Al. The working chambers of the radial piston compressor are equipped at the head end with an inlet valve cover containing an inlet valve. The inlet valve comprises an inlet channel in the inlet valve cover and a valve plate.

[0008] The intake valves are typically designed as reed valves. The valve blanks are pressed onto the bearing surfaces of the corresponding receptacles perpendicular to the piston's axis of movement by a retaining ring via the intake valve covers. During the intake stroke, the incoming gas passes through the intake port in the intake valve cover axially to the piston's axis of movement and presses the valve blade against a stop on the cylinder block. When the gas is compressed by the piston's movement towards the intake valve, the valve blade is forced back into its initial position, sealing the intake port.

[0009] The inlet valve preferably comprises a circular valve plate with a cut-out tongue contour. The tongue contour (hereinafter referred to as the valve tongue) together with the inlet port forms the actual valve. The opening behavior can be compared to a bending beam clamped at one end, with pressure applied to the free end.

[0010] As with a conventional bending beam, the highest bending moment is found at the clamping point (here, the transition of the valve tongue to the circular valve plate). To ensure optimal inflow performance, a large inflow cross-section and a large valve opening (valve tongue deflection) are desirable. Due to the limited installation space and length of the valve tongue, material-critical bending tensile stresses occur at the valve tongue clamping point. Furthermore, the maximum bending tensile stresses are superimposed on the stresses resulting from the pressure of the intake valve cover on the valve plate. The position of the exhaust port below the valve tongue clamping point can lead to the accumulation of dirt particles.

[0011] The object of the present invention is to propose an improved radial piston compressor, in particular a radial piston compressor whose valve plate is designed with a constructive optimization of the valve tongue contour in order to reduce the critical load in the clamping area.

[0012] According to the invention, this problem is solved by a radial piston compressor with the characterizing features of claim 1. By connecting the valve tongue to the valve plate via two valve feet, wherein the valve feet are curved outwards and taper towards the valve tongue, an improved radial piston compressor can be provided. In particular, a radial piston compressor can be provided whose valve plate features a structurally optimized valve tongue contour to reduce the critical load in the clamping area. A special feature of the valve plate is the way the valve feet are designed. Unlike comparable compressors and their valves (which run parallel and have a constant width over their entire length), these feet are parabolic and project from (or point away from) each other.Furthermore, the width of the valve feet preferably increases uniformly towards the clamping point. This is achieved structurally, among other things, by a cutout in the form of an acute-angled isosceles triangle with parabolic legs and rounded corners. The valve width also preferably tapers parabolically from the circular valve head towards the clamping point before the two valve feet are formed. This results in a valve head with a balloon-shaped or bulbous cross-section.

[0013] Further advantageous embodiments of the proposed invention arise in particular from the features of the dependent claims. The subject matter or features of the various claims can, in principle, be combined with one another in any way.

[0014] In an advantageous embodiment of the invention, a triangular clearance can be arranged between the valve feet, the clearance angle (a) of which, oriented towards the valve tongue, is between 30 and 40 degrees, preferably 35°. This allows for the design of a radial piston compressor whose valve plate features a structurally optimized valve tongue contour to reduce the critical load in the clamping area. To ensure optimal inflow performance, a large inflow cross-section is desirable. This can ultimately be achieved by means of a large valve opening or a large deflection of the valve tongue. For this configuration, 35° has proven to be a very suitable clearance angle. A similar result could certainly be achieved within a 5° range around this optimum.The angle determines a favorable ratio between stiffness and the position of the bending maximum. The angle range, or preferred angle, depends in particular on the specific design and geometry. In other words, the optimal angle range is determined according to the specific boundary conditions. In a further advantageous embodiment of the invention, the intake valve cover and the valve plate can be received in a receptacle with a support surface, wherein the valve plate is received, in particular clamped, between the intake valve cover and the support surface. The valve plate can be arranged between the intake valve cover and the receptacle or support surface like a conventional valve plate, wherein the valve plate, in particular the valve tongue, is optimized with regard to its bending behavior.

[0015] In a further advantageous embodiment of the invention, the relief from the edge of the receptacle can extend into the valve plate in the form of an acute-angled triangle with rounded corners, creating a symmetrical separation of the two valve bases. This relief does not serve as an opening for the fluid outlet channel, but rather promotes stress relief and prevents dirt deposits and pressure pulsations.

[0016] In a further advantageous embodiment of the invention, it can be provided that the valve tongue has a balloon-shaped head in cross-section, wherein the valve plate has a valve center, wherein the cross-section of the balloon-shaped head of the valve tongue decreases in the direction of the valve center and ends in the two outwardly curved valve feet.

[0017] The balloon-shaped head provides a sufficiently large surface area to allow the valve to open quickly during intake, as the force acting on the valve increases with the surface area. Furthermore, it ensures a reliable seal on the intake port during gas compression. The taper towards the center of the valve provides a smooth transition to the curved valve stems, resulting in low stiffness and thus greater deflection at low stresses.

[0018] In a further advantageous embodiment of the invention, it can be provided that the cross-section of a valve foot increases uniformly as it approaches the clamping point.

[0019] This results in a uniformly smooth transition from the valve base width to the clamping point on the valve plate, thereby reducing bending stresses and further positioning them towards the center of the valve to prevent the bending stresses from being superimposed on the Hertzian contact stress between the valve plate and the bearing surface. In a further advantageous embodiment of the invention, the recess can be fully covered by the inlet valve cover. The recess does not serve as an opening for the fluid outlet channel, but rather promotes stress relief and prevents dirt deposits and pressure pulsations.

[0020] In a further advantageous embodiment of the invention, the arrangement consisting of the valve tongue, the two valve bases, and the relief can be configured in a Y-shape. The Y-shaped configuration of the valve plate or valve tongue allows for a radial piston compressor whose valve plate features a structurally optimized valve tongue contour to reduce the critical load in the clamping area. To ensure optimal inflow performance, a large inflow cross-section is desirable. This can ultimately be achieved by means of a large valve opening or by deflecting the valve tongue.

[0021] In a further advantageous embodiment of the invention, it can be provided that the inlet valve is designed with a diameter of the inlet cross-section of the fluid inlet channel of 5.5 mm, an inlet pressure of 8.2 bar and a maximum deflection h to the stop of 1 mm.

[0022] In a further advantageous embodiment of the invention, it can be provided that the release has a release length and the valve tongue has a valve tongue length, wherein the ratio of the release length to the valve tongue length is 1 / 2.5.

[0023] In a further advantageous embodiment of the invention, it can be provided that the valve tongue has a maximum width and a minimum width, wherein the ratio of maximum width to minimum width is 1 / 0.3.

[0024] In a further advantageous embodiment of the invention, the valve base can have a minimum width and the clamping has a maximum width, wherein the minimum width of the valve base increases at the transition to the valve tongue, in particular increasing uniformly, with the ratio of the minimum width of the valve base to the maximum width of the clamping being 1 / 2.1. Further features and advantages of the present invention will become clear with reference to the following description of preferred embodiments and the accompanying figures.

[0025] Fig. 1 shows a radial piston compressor in a side-cut view;

[0026] Fig. 2 shows a radial piston compressor in a cutaway view from the front;

[0027] Fig. 3 shows a radial piston compressor in a cutaway view from the front;

[0028] Fig. 4 shows an enlarged view of a section of a radial piston compressor according to

[0029] Fig. 3;

[0030] Fig. 5 shows a cylinder housing of a radial piston compressor in a perspective view;

[0031] Fig. 6a, b shows an exploded view of a receiver, an inlet valve and an inlet valve cover of a radial piston compressor;

[0032] Fig. 7 shows a schematic representation of an intake valve cover with an intake valve;

[0033] Fig. 8 shows a valve plate for a radial piston compressor in a top view;

[0034] Fig. 9 shows a valve plate for a radial piston compressor in a top view;

[0035] Fig. 10 shows a valve plate for a radial piston compressor according to the invention in a top view;

[0036] Fig. 11 shows an exploded view of a fitting, an inlet valve and a

[0037] Inlet valve cover of a radial piston compressor according to the invention in a top view;

[0038] Fig. 12 shows a valve plate for a radial piston compressor according to the invention in a top view;

[0039] Fig. 13 shows a valve plate for a radial piston compressor according to the invention in a top view;

[0040] Fig. 14 shows a valve plate for a radial piston compressor according to the invention in a top view;

[0041] The following reference symbols are used in the illustrations:

[0042] R axis of rotation

[0043] K Piston axis

[0044] M Valve center

[0045] A clearance length

[0046] B Valve tongue length

[0047] C greatest width of the valve tongue

[0048] The smallest width of the valve tongue

[0049] E smallest width of the valve base

[0050] F greatest width at the clamping point

[0051] G Diameter of the inlet channel a Clearance angle / Angle of clearance h Opening height

[0052] L bending length

[0053] 1 compressor unit

[0054] 2 Drive unit

[0055] 3 retaining rings

[0056] 4 High-pressure collector channel

[0057] 5 bearings

[0058] 6 bearings

[0059] 7 warehouses

[0060] 11 Drive shaft

[0061] 12 eccentric discs

[0062] 13 Piston working chamber assembly

[0063] 14 Piston guide ring

[0064] 15 Intake valve covers

[0065] 16 cylinder housings

[0066] 17 high-pressure lids

[0067] 18 Recess for intake valve cover

[0068] 21 Drive housing 3 Rotor 4 Inlet valve 5 Exhaust valve 1 Bearing mount 1 Bearing mount

[0069] 52 Bearing intake

[0070] 121 eccentric bearings

[0071] 131 Workspace

[0072] 132 pistons

[0073] 133 Transmission element

[0074] 151 Seal

[0075] 181 contact area

[0076] 241 Fluid inlet channel

[0077] 242 Valve plate

[0078] 251 Fluid outlet channel

[0079] 2421 Valve tongue

[0080] 2422 Valve base

[0081] 2423 Fitting bore

[0082] 2424 Clamping

[0083] 2425 recess

[0084] 2426 Exemption Features and details described in connection with a method naturally also apply in connection with the device according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always makes or can make reciprocal reference. Furthermore, any method described according to the invention can be carried out with the device according to the invention.

[0085] The terminology used herein serves only to describe certain embodiments and is not intended to limit the disclosure. As used herein, the singular forms "a" and "the" are intended to include the plural forms unless the context otherwise makes clear. It will also be clear that the expressions "indicates" and / or "indicating," when used in this description, specify the presence of the aforementioned features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the expression "and / or" includes any and all combinations of one or more of the associated, listed elements.

[0086] First, reference is made to Figures 1 and 2.

[0087] A radial piston compressor essentially comprises a compressor unit 1 and a drive unit 2. The radial piston compressor includes a housing, which can be composed of individual housing components, such as, for example, in the present embodiment, a drive housing 21, a cylinder housing 16, and a high-pressure cover 17. Other housing configurations are also conceivable.

[0088] The compressor unit 1 comprises a drive shaft 11 with an eccentric disc 12. The combination of drive shaft 11 and eccentric disc 12 can also be referred to as an eccentric shaft. The drive shaft 11 has a pivot axis D. The compressor unit 1 comprises at least one piston-working chamber assembly 13, preferably several piston-working chamber assemblies 13, 13a, 13b... 13f, which are arranged radially around the drive shaft 11. The indices "a", "b", etc. accordingly represent further piston-working chamber assemblies. The piston-working chamber assemblies 13 can also be described as having a star-shaped arrangement around the drive shaft 11. The piston-working chamber assembly 13 comprises a working chamber 131 with a piston 132 slidably arranged therein. The piston 132 has a piston axis K. The direction of displacement of the piston 132 corresponds to the piston axis K. The working chamber 131 can also be referred to as a cylinder or cylinder bore.The working chamber 131 is equipped with an inlet valve cover 15 at the cylinder head. The working chambers 131 of the piston-working chamber assemblies 13 can be formed at least partially, preferably completely, from the cylinder housing 16.

[0089] The drive shaft 11, in turn, can be set in rotation by the drive unit 2, which can, for example, be designed as an electric motor. As the drive shaft 11 rotates, the eccentric disk 12 engages the piston 132 and moves it within the working chamber 131, thereby compressing the medium in the working chamber, for example, a refrigerant. The return movement of the piston 132 can be effected, for example, by a piston guide ring 14 in contact with the piston 132. In this way, the piston 132 can be moved back to bottom dead center (BDC) until the eccentric disk 12 again engages the piston crown. The piston 132, in particular the piston crown, can also be equipped with a transmission element 133, or a transmission element 133 can be arranged between the eccentric disk 12 and the piston 132.The transmission element 133 transfers the stroke of the eccentric disc 12 to the piston 132, enabling the piston to perform the compression movement towards top dead center (TDC). The transmission element 133 can be made of a different material than the piston 132 and eccentric disc 12, particularly plastic. This can, for example, reduce wear or provide some damping when the eccentric disc 12 impacts the piston. The eccentric disc 12 can also be equipped with an eccentric bearing 121, particularly a needle bearing.

[0090] Figure 1 also shows a receptacle 31 for a bearing 6, another receptacle 41 for a bearing 7, and a receptacle 52 for a bearing 5. The rotor of the drive device, in this case the rotor of an electric motor, is designated by reference numeral 23.

[0091] The further details and operation of a radial piston compressor are sufficiently known to those skilled in the art. For further details, reference can be made, for example, to DE 10 2020 211 680 A1.

[0092] Reference is made in particular to Figures 3 to 5 below. The intake valve cover 15 is received in a recess 18 above the respective working chamber 131. The recess 18 is designed as a cutout in the cylinder housing 16 and includes a shoulder as a support surface 181 for a valve plate 242 or the intake valve cover 15. The valve plate 242 rests on the support surface 181 at its edge, and the intake valve cover rests on the valve plate 242. In other words, the valve plate 242 is received or clamped between the intake valve cover 15 and the support surface 181.

[0093] The shape of the receptacle 18 or recess ultimately depends on the shape of the intake valve cover 15, such that the intake valve cover 15, possibly with a circumferential seal 151, and the valve plate 242 can be accommodated in the receptacle 18. A circular cylindrical recess 18 and a flat circular cylindrical intake valve cover 15 are shown here. The circular cylindrical recess 18 can also be referred to as a cover bore. The indices "a", "b", etc. designate further intake valve covers accordingly. Each piston-working chamber assembly is assigned a valve cover.

[0094] The inlet valve cover 15 includes an inlet valve 24. The inlet valve 24 includes a fluid inlet channel 241, as well as the valve plate 242.

[0095] The valve plate 242 in turn comprises a valve tongue 2421. The inlet valve 24, in particular the valve tongue 2421, is designed to selectively close or open the fluid inlet channel 241.

[0096] The fluid to be compressed flows into the working chamber 131 via the fluid inlet channel 241, is compressed there by the stroke movement of the piston 132 and leaves the working chamber 131 through a fluid outlet valve 25 or fluid outlet channel 251.

[0097] The design of the valves, for example as a spring-loaded sheet valve, is sufficiently known to those skilled in the art and requires no further explanation here.

[0098] It is specifically provided that the fluid inlet channel 241 is aligned radially to the axis of rotation D of the drive shaft 1 of the radial piston compressor. It is specifically provided that the fluid outlet channel 251 is aligned axially to the axis of rotation D of the drive shaft 1 of the radial piston compressor. The fluid outlet channel 251 opens into a high-pressure collecting channel 4.

[0099] In particular, Fig. 4 illustrates the system pressures acting on the system and the pressure surfaces involved in the intake valve cover 15, which is arranged radially to the drive shaft 1. The valve plate 242 rests on the support surface 181 of the receptacle 18 at its edge and is pressed onto the support surface 181 by the intake valve cover 15.

[0100] When the piston 132 moves from its upper end position to its lower end position, a vacuum is created in the working chamber 131 between the piston head and the intake valve cover 15. The intake valve 24 opens into the working chamber 131, and fresh gas is drawn in through the fluid intake port 241. Specifically, the valve reed 2421 is lifted from the intake valve cover 15 against its bending force, and the intake port 241 is opened accordingly. After the piston reaches bottom dead center (BDC), the piston 132 moves upwards again, the intake valve 242 closes, and the gas in the working chamber 131 is compressed. Specifically, the valve reed 2421 springs back and closes the intake port 241 again. The compressed gas then exits the working chamber 21 through the exhaust valve 25, specifically the fluid outlet 251.

[0101] Particular reference is made below to Fig. 5.

[0102] The radial piston compressor can be equipped with at least one, preferably one, retaining ring 3 for securing all inlet valve covers 15, 15a to 15e of the radial piston compressor. In other words, it is particularly intended to secure the inlet valve covers 15(ae) of all piston-working chamber assemblies 13(ae) simultaneously by means of only one common retaining ring 3. This is shown in particular in Fig. 5 using the example of a 6-cylinder radial piston compressor. Thus, the retaining ring 3 generates the necessary holding force to keep all inlet valve covers 15 in position under operating conditions.

[0103] Reference is made below to Figures 6a and 6b.

[0104] Figures 6a and 6b show details of the radial piston compressor, in particular the receptacle 18 with the support surface 181 for the inlet valve cover 15 and the valve plate 242. Figure 6b shows details of another variant of a radial piston compressor, in particular the receptacle 18 with the support surface 181 for the inlet valve cover 15 and the valve plate 242. The circular valve plate 242 is inserted into the receptacle 18 as follows.

[0105] Particular reference is made below to Fig. 7.

[0106] Fig. 7 shows the intake valve cover 15 with intake valve 24 in a general sectional view. The valve tongue 2421 is resiliently connected to the valve plate 242. Fig. 8 further shows the intake valve 24 in the open state with an opening height (h) and a bending length (L). To ensure that the material stresses in this open state are permanently tolerable, the bending length (L) (distance from the clamping point to the center of the valve tongue) should be as large as possible.

[0107] Particular reference is made below to Figures 8 and 9.

[0108] The aforementioned figures show a valve plate 242 according to the prior art for an inlet valve of a radial piston compressor.

[0109] First, particular reference is made to Fig. 8.

[0110] In addition to the valve tongue 2421 and fitting bores 2423 already described above, the clamping element 2424 is shown. A recess 2425 in the valve plate 242 is also visible, through which the valve tongue 2421 is ultimately formed in the valve plate 242.

[0111] Particular reference is made below to Fig. 9.

[0112] The utilization rate of a valve plate 242 is shown according to the state of the art.

[0113] In valve plates 242 according to the prior art, the width of the valve tongue 2421 is almost uniform along its length. The recesses 2425 to the right and left of the valve tongue 2421, which separate the valve tongue 2421 from the valve plate 242, run almost parallel. This results in a greater required tongue length to ensure the necessary displacement under low tensile stresses. The maximum tensile stresses occur at the clamping point 2424 of the valve tongue 2421 and are located very close to the edge of the valve plate 242. Furthermore, these tensile stresses are superimposed on the stresses caused by the compression of the retaining ring 3. The large, maximum stresses / stress distributions are indicated by dark areas in Fig. 9.

[0114] In Fig. 9, the utilization rate of the valve plate 242 with an inlet channel cross-section or inlet channel diameter G (see Fig. 14) of 5.5 mm is shown in particular.

[0115] Reference is made below to Figures 10 to 14.

[0116] Figures 10 to 14 show a valve plate for a radial piston compressor according to the invention.

[0117] According to the invention, the valve tongue 2421 is connected to the valve plate via two valve feet 2422, wherein the valve feet are curved outwards and taper towards the valve tongue.

[0118] The unique feature of this valve plate is the design of its valve feet. Unlike comparable compressors and their valves (which run parallel and have a constant width along their entire length), these feet are parabolic and project from each other (or point away from each other). Furthermore, the width of the valve feet preferably increases uniformly towards the clamping point. This is achieved, among other things, by a design feature in the form of an acute-angled isosceles triangle with parabolic legs and rounded corners. The valve width also preferably tapers parabolically from the circular valve head towards the clamping point before the two valve feet are formed. This results in a valve head with a balloon-like or bulbous cross-section.

[0119] It is therefore preferably provided that a triangular clearance 2426 is arranged between the valve stems 2422, the clearance angle α of which, oriented towards the valve tongue, is between 30 and 40 degrees, preferably 35°. It has been shown that 35° is very suitable as an opening angle. Certainly, a similar result could be achieved within a 5° range around this optimum. The angle determines a favorable ratio between stiffness and the position of the bending maximum. Thus, a different angle could be advantageous for configurations with a different inlet cross-section or a change in the inlet port position. The valve tongue 2421 has a balloon-shaped head in cross-section, the cross-section of which decreases towards the valve center M and terminates in the two outwardly curved valve stems 2422. The cross-section of a valve stem 2422 increases uniformly as it approaches the clamping 2424.The cutout 2426 extends from the edge of the receptacle 18, in particular of the valve plate 242, specifically in the form of an acute-angled triangle with rounded corners into the valve plate 242, and forms the symmetrical separation of the two valve stems 2422. The cutout 2426 does not serve as an opening for the fluid outlet channel, but rather promotes stress relief and prevents dirt deposits and pressure pulsations. In other words, the cutout 2426 is preferably completely covered by the inlet valve cover 15.

[0120] Because of the shape of the valve tongue 2421, valve base 2422 and relief 2426, it can also be referred to as a Y-valve. This design is illustrated by the “Y” shown in Fig. 13.

[0121] In a preferred embodiment of the valve plate 242 for a radial piston compressor according to the invention, the following design parameters can be provided.

[0122] The contour was preferably designed for an inlet valve 24 with an inlet cross-section G of the fluid inlet channel 241 of 5.5 mm², an inlet pressure of 8.2 bar, and a maximum deflection h to the stop of 1 mm. The following ratios proved advantageous: The ratio of the length A of the clearance to the valve tongue length B is 1 / 2.5. The greatest width C of the valve tongue, which can also be referred to as the valve head at its greatest width C, is in the ratio 1 / 0.3 to the smallest width D of the valve tongue. The smallest width E of a valve base 2422 at the transition to the valve tongue 2421 increases uniformly and is in the ratio 1 / 2.1 to the greatest width F at the clamping 2424. The clearance angle a of the clearance 2426 is 35°.

[0123] Reference is made below to Fig. 14.

[0124] Here, the utilization rate of the valve plate for a radial piston compressor according to the invention with an inlet channel cross-section of 5.5 mm is shown.

[0125] The following advantages result in particular. Advantageously, a Y-shaped valve tongue contour is proposed, which is characterized in particular by outwardly curved valve feet 2422. This results in a longer valve tongue 2421 without the stress maxima being too close to the clamping 2424. To reduce pressure pulsations and simultaneously prevent the deposition of dirt particles above the fluid outlet channel 251 between the valve plate 242 and the bearing surface 181 in the cylinder housing 16, it is advantageous to create a relief 2426 at the edge of the valve plate 242. A shift of the tensile stress maxima can be achieved by the increasing taper of the feet 2422 towards the free end of the valve tongue 2421. The relief 2426 also results in a lower stiffness of the valve tongue 2421, which allows a larger valve opening h to be achieved at lower stresses. In the Fig.The black areas at the feet are meant to indicate the tensions in 14.

[0126] This prevents the tensile stresses from superimposing on the stresses in the contact area. The Hertzian contact stress occurs on the valve's bearing surface on the intake valve cover. The valve stems rest on the intake valve cover, which means that positioning the bending stress at the same point leads to a higher equivalent stress.

[0127] It is evident that the radial piston compressor described here, or the valve plate 242 of the radial piston compressor described here, is characterized in particular by the following features.

[0128] The clearance 2426 is preferably placed in the direction of the outlet channel 251 under the cover 15 (see in particular Fig. 11).

[0129] In the radial piston compressor according to the invention, the clearance 2426 is preferably located exactly above the point from which the compressed gas flows through the laterally attached outlet channel 251 in the cylinder in order to leave the cylinder housing.

[0130] The purpose of the clearance 2426 is, among other things, to ensure that the valve reed is not located in the direct outlet flow of the outgoing gas. In other words, the valve reed 2421 should not protrude where the flow velocity is greatest. The outflow process should not be obstructed. The clearance 2426 also increases the volumetric efficiency – both inlet and outlet. This also results in an improved inflow process, as it allows for an effectively larger valve opening.

[0131] The valve plate 242 is characterized in particular by the inverted Y-shape of the combination of valve tongue 2421 and valve feet 2422 and / or the outwardly curved valve feet 2422. The valve plate 242 is characterized in particular by the taper of the valve feet 2422 in the direction of the head of the valve tongue 2421.

[0132] The radial piston compressor described here, or the valve plate of the radial piston compressor described here, can be characterized in particular by the specified conditions for the valve design.

[0133] Furthermore, the following variations of the invention are conceivable, in particular, without departing from the inventive concept. For example, it is conceivable to change the clearance size in combination with adjusting the taper and curvature of the valve feet, as well as the size ratios.

[0134] An advantage of the valve design and the resulting stress distribution, besides reduced stress maxima, is that the stress maximum in the area of ​​the valve tongue 2421 is located at the transition radius with respect to the vibratory finishing process, at a point only minimally affected by the process and at a certain distance from the edge. This minimizes the influence of the vibratory finishing process on the fatigue strength of the valve. Furthermore, a change occurs from an almost purely tensile-bending stress to a stress state with higher multiaxiality.

Claims

Claims 1. Radial piston compressor, comprising - a compressor unit (1) and a drive unit (2) for driving the compressor unit (1), wherein - the compressor unit (1) comprises a plurality of piston working chamber assemblies (13) arranged radially around an eccentric shaft (11, 12), wherein - the eccentric shaft is driven by the drive device (2), wherein - each piston-cylinder bore assembly (13) comprises a piston (132) that is movable in a working space (131), wherein - an inlet valve cover (15) with an inlet valve (24) is arranged at the head end of the working chamber (131), wherein - the inlet valve (24) comprises a fluid inlet channel (241) in the inlet valve cover (15), as well as a valve plate (242) with a valve tongue (2421), wherein the valve tongue (2421) is configured to selectively close or open the fluid inlet channel (241), characterized in that - the valve tongue (2421) is connected to the valve plate (242) via two valve feet (2422), wherein the valve feet (2422) are curved outwards and taper towards the valve tongue (2421).

2. Radial piston compressor according to claim 1, characterized in that a triangular clearance (2426) is arranged between the valve feet (2422), the clearance angle (a) of which is oriented towards the valve tongue (2421) is between 30 and 40 degrees, preferably 35°.

3. Radial piston compressor according to at least one of the preceding claims, characterized in that the inlet valve cover (15) and the valve plate (242) are received in a receptacle (18) with a support surface (181), wherein the valve plate (242) is received, in particular clamped, between the inlet valve cover (15) and the support surface (181).

4. Radial piston compressor according to at least one of the preceding claims, characterized in that the clearance (2425) from the edge of the receptacle (18) is in the form of a acute-angled triangle with rounded corners extends into the valve plate 242 and forms a symmetrical separation of the two valve feet (2422).

5. Radial piston compressor according to at least one of the preceding claims, characterized in that the valve tongue 2421 has a balloon-shaped head in cross-section, wherein the valve plate has a valve center, wherein the cross-section of the balloon-shaped head of the valve tongue decreases in the direction of the valve center M and terminates in the two outwardly curved valve feet 2422.

6. Radial piston compressor according to at least one of the preceding claims, characterized in that the cross-section of a valve foot 2422 increases uniformly as it approaches the clamping point 2424.

7. Radial piston compressor according to at least one of the preceding claims, characterized in that the clearance 2426 is fully covered by the inlet valve cover (15).

8. Radial piston compressor according to at least one of the preceding claims, characterized in that the arrangement consisting of the valve tongue, the two valve feet (2422) and the release (2426) is Y-shaped.

9. Radial piston compressor according to at least one of the preceding claims, characterized in that the inlet valve 24 is designed with an inlet cross-section of the fluid inlet channel 241 of 5.5 mm, an inlet pressure of 8.2 bar and a maximum deflection h to the stop of 1 mm.

10. Radial piston compressor according to at least one of the preceding claims, characterized in that the clearance has a length A and the valve tongue has a length B, wherein the ratio of the clearance length (A) to the valve tongue length (B) is 1 / 2.

5.

11. Radial piston compressor according to at least one of the preceding claims, characterized in that the valve tongue has a maximum width (C) and a minimum width (D), wherein the ratio of maximum width (C) to minimum width (D) is 1 / 0.

3.

12. Radial piston compressor according to at least one of the preceding claims, characterized in that the valve base has a minimum width (E) and the clamping has a maximum width (F), wherein the minimum width (E) of a valve base (2422) is at the transition to the The valve tongue (2421) rises, in particular rises uniformly, wherein the ratio of the smallest width (E) of the valve foot and the largest width (F) of the clamping is 1 / 2.1.

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