VACUUM PUMP

Abstract

A vacuum pump for supplying a machine assembly with negative pressure, the vacuum pump including a housing featuring a delivery chamber which includes a chamber inlet opening and a chamber outlet opening for a gaseous fluid; a suction port for establishing a fluid connection to the machine assembly; a suction channel which connects the delivery chamber to the suction port; and a relief channel which connects the delivery chamber to a relief opening of the housing; a delivery member which can rotate in the delivery chamber in a forward rotational direction and a reverse rotational direction. The fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in the forward rotational direction.

Claims

1.-16. (canceled)

17. A vacuum pump for supplying a machine assembly with negative pressure, the vacuum pump comprising: 1.1 a housing featuring: 1.1.1 a delivery chamber which comprises a chamber inlet opening and a chamber outlet opening for a gaseous fluid; 1.1.2 a suction port for establishing a fluid connection to the machine assembly; 1.1.3 a suction channel which emerges into the delivery chamber via the chamber inlet opening and connects the delivery chamber to the suction port; and 1.1.4 a relief channel which connects the delivery chamber to a relief opening of the housing; 1.2 a delivery member which can rotate in the delivery chamber in a forward rotational direction and a reverse rotational direction, wherein the fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in the forward rotational direction; and 1.3 a relief valve for closing the relief opening when the delivery member rotates in the forward rotational direction and opening the relief opening when the delivery member rotates in the reverse rotational direction, 1.4 wherein the relief channel emerges into the suction channel.

18. The vacuum pump according to claim 17, wherein the relief channel emerges into the suction channel at a distance from the chamber inlet opening by a length measured along the suction channel.

19. The vacuum pump according to claim 17, wherein the suction channel exhibits a length from the chamber inlet opening to a channel intersection at which the relief channel emerges into the suction channel which is at least as large as a smallest width of the chamber inlet opening.

20. The vacuum pump according to claim 17, wherein the relief opening and a channel intersection at which the relief channel emerges into the suction channel are equal in size.

21. The vacuum pump according to claim 17, wherein the housing comprises a discharge opening connected to the chamber outlet opening, and the vacuum pump comprises a main valve in order to prevent the fluid from being suctioned through the discharge opening and to allow the fluid to be discharged through the discharge opening.

22. The vacuum pump according to claim 21, wherein the relief valve and the main valve are each formed as a reed valve comprising a spring-elastic valve tongue and an abutment for the valve tongue.

23. The vacuum pump according to claim 22, wherein the valve tongue of the relief valve and the valve tongue of the main valve are connected to each other via a common fastening region.

24. The vacuum pump of claim 23, wherein the valve tongues are connected in an L shape or U shape via the common fastening region.

25. The vacuum pump according to claim 22, wherein the abutment of the relief valve and the abutment of the main valve are connected to each other via a common fastening region.

26. The vacuum pump according to claim 25, wherein the abutments are connected to each other in an L shape or U shape via the common fastening region.

27. The vacuum pump according to claim 22, wherein the relief valve and the main valve together form a double reed valve.

28. The vacuum pump according to claim 22, wherein the valve tongue of the relief valve and the valve tongue of the main valve are produced in one piece and protrude, as viewed in a plan view, from a common fastening region at an enclosed angle α, wherein α<180° or α<150° or α<120°.

29. The vacuum pump according to claim 28, wherein α>40° or α>60°.

30. The vacuum pump according to claim 29, wherein α is 90° with a deviation of at most ±20°.

31. The vacuum pump according to claim 22, wherein the abutment of the relief valve and the abutment of the main valve are produced in one piece and protrude, as viewed in a plan view, from a common fastening region at an enclosed angle β, wherein β<180° or β<150° or β<120°.

32. The vacuum pump according to claim 31, wherein β>40° or β>60°.

33. The vacuum pump according to claim 32, wherein β is 90° with a deviation of at most ±20°.

34. The vacuum pump according to claim 17, wherein the housing comprises a discharge opening which is connected to the chamber outlet opening via a discharge channel.

35. The vacuum pump according to claim 34, wherein the mean flow cross-section of the relief channel and the mean flow cross-section of the discharge channel differ from each other.

36. The vacuum pump according to claim 17, wherein a reflux valve separates the suction channel from the machine assembly when the delivery member rotates in the reverse rotational direction.

37. The vacuum pump according to claim 17, wherein the vacuum pump is a valve cell pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The invention is explained below on the basis of example embodiments. Features disclosed by the example embodiments advantageously develop the subject-matter of the claims, the subject-matter of the aspects and the embodiments explained above.

There is shown:

[0091] FIG. 1 an isometric view of a first example embodiment of the vacuum pump;

[0092] FIG. 2 a plan view onto the relief valve and main valve of the first example embodiment;

[0093] FIG. 3 a plan view onto the relief and discharge opening of the first example embodiment;

[0094] FIG. 4 a schematic representation of the channel intersection of the relief channel;

[0095] FIG. 5 a schematic representation of the chamber inlet opening and the chamber outlet opening;

[0096] FIG. 6 an isometric view of a second example embodiment of the vacuum pump;

[0097] FIG. 7 a section through the isometric view of the second example embodiment;

[0098] FIG. 8 a section of the vacuum pump of the second example embodiment in a front view;

[0099] FIG. 9 a plan view onto the relief valve and main valve of the second example embodiment;

[0100] FIG. 10 a plan view onto the relief and discharge opening of the second example embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0101] FIG. 1 discloses a vacuum pump of a first example embodiment in an isometric view. The vacuum pump is a vane cell pump comprising a delivery member 10, 20, wherein the delivery member comprises a rotor 10 and a vane 20. The delivery member 10, 20 is mounted such that it can rotate in a forward rotational direction and a reverse rotational direction in a delivery chamber which is formed in a cylindrical cavity in the pump housing 30. The delivery chamber comprises a chamber inlet opening 40 and a chamber outlet opening 50. By rotating the delivery member 10, 20 in the forward rotational direction, fluid is suctioned via the chamber inlet opening 40 and discharged through the chamber outlet opening 50. A suction channel 41 which extends upstream of the chamber inlet opening 40 in relation to a flow formed when the delivery member 10, 20 rotates in the forward rotational direction extends as far as a suction port 46 (not shown in more detail). A machine assembly can be connected to the vacuum pump via the suction port 46, directly or via another feed conduit, such that the vacuum pump can supply the machine assembly with negative pressure.

[0102] A reflux valve (also not shown) which is formed in the region of the suction port 46 opens the suction channel 41 when the delivery member 10, 20 rotates in the forward rotational direction and closes it when the delivery member 10, 20 rotates in the reverse rotational direction. The suction channel 41 extends from the suction port 46 up to the delivery chamber, wherein the chamber inlet opening 40 represents the point at which the suction channel 41 emerges into the delivery chamber.

[0103] In an upstream direction from the chamber inlet opening 40 in relation to a flow formed when the delivery member 10, 20 rotates in the forward rotational direction, a relief channel 42 diverges from the suction channel 41 and/or emerges into the suction channel 41. The relief channel 42 connects the delivery chamber to a relief opening 43 of the housing 30. The channel intersection 44 at which the relief channel 42 emerges into the suction channel 41 is situated upstream of the chamber inlet opening 40 and downstream of the suction port 46 (not shown) in relation to a flow formed when the delivery member 10, 20 rotates in the forward rotational direction. In other words, the channel intersection 44 at which the relief channel 42 emerges into the suction channel 41 is formed between the chamber inlet opening 40 and the suction port 46 in relation to the suction channel 41.

[0104] The relief channel 42 extends from the channel intersection 44 up to a relief opening 43. The relief opening 43 is closed by a relief valve 60 when the delivery member 10, 20 rotates in the forward rotational direction and is opened by the relief valve 60 when the delivery member 10, 20 rotates in the reverse rotational direction. The relief valve 60 is formed in the region of the relief opening 43. The relief valve 60 is formed as a reed valve comprising a spring-elastic valve tongue 62 and an abutment 63 for the spring-elastic valve tongue 62. Depending on the operating state of the vacuum pump, i.e. the rotational direction of the delivery member 10, 20, the spring-elastic valve tongue 62 either abuts the abutment 63 of the relief valve 60 and thus opens the relief opening 43 or overlaps the relief opening 43 such that the relief opening 43 is closed by the spring-elastic valve tongue 62.

[0105] As can be seen from FIG. 1, the relief valve 60 forms a double reed valve together with a main valve 70. The main valve 70, which forms the double reed valve together with the relief valve 60, closes a discharge opening 53 which is connected to the chamber outlet opening 50 via a discharge channel 52. The discharge opening 53 serves to discharge the delivered fluid, in particular air, into the environment of the vacuum pump when the delivery member 10, 20 rotates in the forward rotational direction.

[0106] The main valve 70 is formed as a reed valve comprising a spring-elastic valve tongue 72 and an abutment 73 for the spring-elastic valve tongue 72. The main valve 70 is formed in the region of the discharge opening 53, wherein the spring-elastic valve tongue 72 is designed to be pivotable between the abutment 73 and the discharge opening 53. Depending on the operating state of the vacuum pump, i.e. the rotational direction of the delivery member 10, 20, the spring-elastic valve tongue 72 opens or closes the discharge opening 53. The main valve 70 connects the delivery chamber in fluid communication with the environment of the vacuum pump via the chamber outlet opening 50 when the delivery member 10, 20 rotates in the forward rotational direction and separates the delivery chamber from the environment of the vacuum pump when the delivery member 10, 20 rotates in the reverse rotational direction, i.e. the main valve 70 operates in the opposite way to the relief valve 60.

[0107] While the vacuum pump is in operation, the relief valve 60 separates the fluid-communication connection between the delivery member and the environment of the vacuum pump via the relief opening 43 when the delivery member 10, 20 rotates in the forward rotational direction, while the main valve 70 opens the connection between the delivery chamber and the environment of the vacuum pump via the discharge opening 53. Conversely, the relief valve 60 opens the relief opening 43 when the delivery member 10, 20 rotates in the reverse rotational direction, such that a fluid-communication connection is established between the delivery chamber and the environment of the vacuum pump via the relief opening 43, while the main valve 70 closes the discharge opening 53, such that the fluid-communication connection between the delivery chamber and the environment of the vacuum pump via the discharge opening 53 is interrupted. In other words, the relief valve 60 is in a closing position, while the main valve 70 is in an opening position, when the delivery member 10, 20 rotates in the forward rotational direction. Correspondingly, the relief valve 60 is in an opening position, while the main valve 70 is in a closing position, when the delivery member 10, 20 rotates in the reverse rotational direction.

[0108] When the main valve 70 is in its closing position, the spring-elastic valve tongue 72 completely overlaps the discharge opening 53 in a plan view, such that no fluid can flow through the discharge opening 53. Similarly, when the relief valve 60 is in its closing position, the spring-elastic valve tongue 62 completely overlaps the relief opening 43 in a plan view, such that no fluid can flow via the relief opening 43.

[0109] As already mentioned, the relief valve 60 and the main valve 70 together form a double reed valve. This means the abutment 63 of the relief valve 60 and the abutment 73 of the main valve 70 protrude from a common fastening region. The abutment 63 of the relief valve 60 and the abutment 73 of the main valve 70 are produced in one piece with the common fastening region. The abutment 63 of the relief valve 60, the abutment 73 of the main valve 70 and the common fastening region are formed together from sheet metal, in particular by being punched or cut out. The abutment 63 of the relief valve 60, the abutment 73 of the main valve 70 and the common fastening region exhibit a constant thickness b over their entire area.

[0110] As can be seen in FIG. 1 and FIG. 2, the abutment 63 of the relief valve 60 is connected to the abutment 73 of the main valve 70 in an L shape via the common fastening region, i.e. the abutment 63 of the relief valve 60 and the abutment 73 of the main valve 70 protrude from the common fastening region at an enclosed angle β of 90° with a deviation of at most ±20°. The abutment 73 of the main valve 70 protrudes further from the common fastening region than the abutment 63 of the relief valve 60, i.e. the abutment 73 of the main valve 70 forms a longer limb than the abutment 63 of the relief valve 60. It will be obvious to the person skilled in the art that it would also be possible for the abutment 63 of the relief valve 60 to protrude further from the common fastening region than the abutment 73 of the main valve 70 or for the two to protrude to the same extent.

[0111] The statements just made apply similarly to the spring-elastic valve tongue 72 of the main valve 70 and the spring-elastic valve tongue 62 of the relief valve 60, i.e. the spring-elastic valve tongue 62 of the relief valve 60 and the spring-elastic valve tongue 72 of the main valve 70 protrude from a common fastening region, wherein the spring-elastic valve tongue 62 of the relief valve 60 and the spring-elastic valve tongue 72 of the main valve 70 are produced in one piece with the common fastening region, wherein the spring-elastic valve tongue 62 of the relief valve 60 and the spring-elastic valve tongue 72 of the main valve 70 are connected to each other in an L shape via the common fastening region, i.e. the spring-elastic valve tongue 62 of the relief valve 60 and the spring-elastic valve tongue 72 of the main valve 70 protrude from the common fastening region at an enclosed angle α of 90° with a deviation of at most ±20°.

[0112] The spring-elastic valve tongue 72 of the main valve 70 protrudes further from the common fastening region than the spring-elastic valve tongue 62 of the relief valve 60, i.e. the spring-elastic valve tongue 72 of the main valve 70 forms a longer limb than the spring-elastic valve tongue 62 of the relief valve 60. Here, too, it will be obvious to the person skilled in the art to for example have the spring-elastic valve tongue 62 of the relief valve 60 protrude further from the common fastening region than the spring-elastic valve tongue 72 of the main valve 70 or to have the two protrude to the same extent.

[0113] The spring-elastic valve tongue 72 of the main valve 70 and the spring-elastic valve tongue 62 of the relief valve 60 are formed together with the common fastening region from sheet metal, in particular spring sheet metal, by being punched or cut out. The spring-elastic valve tongue 72 of the main valve 70 and the spring-elastic valve tongue 62 of the relief valve 60, together with the common fastening region, thus exhibit a constant thickness b over their entire area.

[0114] The abutment 73 of the main valve 70 and the abutment 63 of the relief valve 60 are connected in a positive fit to the pump housing 30 via their common fastening region and a fastening element. The fastening element of the example embodiment in FIG. 1 and FIG. 2 is formed by a screw. It will be obvious to the person skilled in the art that the connection can also be established for example via a blind rivet or an adhesive, welded or soldered connection.

[0115] The spring-elastic valve tongue 72 of the main valve 70 and the spring-elastic valve tongue 62 of the relief valve 60 are connected to the pump housing 30 via their common fastening region and the same fastening element which already connects the abutment 73 of the main valve 70 and the abutment 63 of the relief valve 60 to the pump housing 30. In a plan view, the abutment 73 of the main valve 70 overlaps the spring-elastic valve tongue 72 of the main valve 70 and the discharge opening 53. Similarly, in a plan view, the abutment 63 of the relief valve 60 overlaps the spring-elastic valve tongue 62 of the relief valve 60 and the relief opening 43. The relief opening 43 is adjacent to the discharge opening 53 in the circumferential direction, wherein the relief opening 43 and the discharge opening 53 are offset with respect to each other in the axial direction.

[0116] FIG. 2 shows the example embodiment of FIG. 1 in a plan view onto the relief valve 60 and the main valve 70. As can be seen from FIG. 2, the abutment 73 of the main valve and the abutment 63 of the relief valve are connected to each other in an L shape via a common fastening region. The valve seat 71 of the main valve is formed by the pump housing 30 which surrounds the discharge channel 52, wherein the discharge opening 53 is covered by the valve abutment 73 of the main valve. The abutment 73 of the main valve can comprise a cavity, as can be seen in FIG. 2. The cavity facilitates the spring-elastic pivoting movement of the valve tongue 72 by enabling the air moved by the spring-elastic valve tongue 72 to flow through the cavity in the abutment 73 of the main valve, such that the flow resistance formed by the abutment 73 of the main valve is reduced. Although the abutment 63 of the relief valve does not show such a cavity in FIG. 2, it should be explicitly indicated that such a cavity can also be provided for the abutment 63 of the relief valve. The spring-elastic valve tongue 72 of the main valve is covered by the abutment 73 of the main valve and can only be seen through the cavity in the abutment 73.

[0117] FIG. 3 shows the first example embodiment of the vacuum pump in a plan view with the abutment of the main valve, the abutment of the relief valve, the spring-elastic valve tongue 72 of the main valve and the spring-elastic valve tongue 62 of the relief valve disassembled. FIG. 3 shows the valve seat 71 of the main valve and the valve seat 61 of the relief valve in a plan view. The valve seat 71 of the main valve is formed by the pump housing which surrounds the discharge channel 52, and the valve seat 61 of the relief valve is formed by the pump housing which surrounds the relief channel 42. It can be seen from FIG. 3 that the discharge opening 53 is larger than the relief opening 43.

[0118] The suction channel 41 is indicated in FIG. 2 and FIG. 3 by an arrow onto the pump housing, i.e. the suction channel 41 itself cannot be seen, but rather only the pump housing 30 which covers it. The relief channel 42 protrudes from the suction channel 41, as can be seen in FIG. 3.

[0119] FIG. 4 and FIG. 5 each show a schematic view of the suction channel 41, comprising the chamber inlet opening 40 and the channel intersection 44, and the discharge channel 52 comprising the chamber outlet 50 and the discharge opening 53. For greater comprehensibility, the inner circumference of the delivery chamber, i.e. the radial boundary surface U of the delivery chamber, is shown unfurled, such that it then appears as a straight line in the schematic plan view of FIG. 4 and as a belt in a schematic radial view. The chamber inlet opening 40 and the chamber outlet opening 50 are adjacent to each other in the circumferential direction of the radial boundary surface U of the delivery chamber, wherein they are embodied to be offset from each other in an axial view. The latter is in particular production-related and shall not restrict the invention to this effect. The chamber inlet opening 40 and the chamber outlet opening 50 can thus be formed level with each other in the axial view.

[0120] The chamber inlet opening 40 exhibits a smaller flow cross-section than the chamber outlet opening 50, wherein the chamber outlet opening 50 extends further than the chamber inlet opening 40 both in the circumferential direction of the radial boundary surface U and in the axial direction. The flow cross-section of the chamber inlet opening 40 and the flow cross-section of the chamber outlet opening 50 are shown to be elliptical in the example embodiment of FIG. 5, but can exhibit any other cross-section, for example a round, rectangular or polygonal cross-section, wherein the smallest width W is understood to mean the extent of the chamber inlet opening 40 which exhibits the smallest diameter. In the present example embodiment of FIG. 5, which shows an elliptical chamber inlet opening 40, the chamber inlet opening does not extend as far in the axial direction as in the circumferential direction of the radial boundary surface U of the delivery chamber.

[0121] The suction channel 41 emerges into the delivery chamber via the chamber inlet opening 40. The suction channel 41 extends in the upstream direction, in relation to a flow established when the delivery member 10, 20 rotates in the forward rotational direction, up to a suction port 46, which is no longer shown, via a reflux valve 45. The reflux valve 45 is preferably formed in the region of the suction port 46. The reflux valve 45 opens the suction channel 41 when the delivery member 10, 20 rotates in the forward rotational direction, such that fluid can flow from the suction port 46 towards the delivery chamber, and prevents fluid from flowing out via the suction port 46 when the delivery member 10, 20 rotates in the reverse rotational direction.

[0122] The reflux valve 45 is formed upstream, in relation to a flow established when the delivery member 10, 20 rotates in the forward rotational direction, of the channel intersection 44 at which the relief channel 42 emerges into the suction channel 41. The channel intersection 44 at which the relief channel 42 emerges into the suction channel 41 is formed upstream of the chamber inlet opening 40 in relation to a flow formed when the delivery member 10, 20 rotates in the forward rotational direction.

[0123] The channel intersection 44 is spaced from the chamber inlet opening 40 in the upstream direction, in relation to a flow established when the delivery member 10, 20 rotates in the forward rotational direction, by the length d, wherein the length d corresponds to at least the smallest width W of the chamber inlet opening 40. In FIG. 4, the length d is more than four times the smallest width W of the chamber inlet opening 40, wherein the length d by which the channel intersection 44 is spaced from the chamber inlet opening 40 is measured along the suction channel 41 and indicates the distance at which the suction channel 41 emerges into the relief channel 42.

[0124] In preferred embodiments, the length d by which the channel intersection 44 is distanced from the chamber inlet opening 40, i.e. the distance from the delivery chamber, is at least as large as the diameter of an equivalent circle whose circular area corresponds to the cross-sectional area of the chamber inlet opening. Where spacing ratios are concerned, the smallest width W is measured on the outline which the chamber inlet opening—in the example, the chamber inlet opening 40—exhibits in the unfurled inner circumferential area and/or in the unfurled radial boundary surface U. Said cross-sectional area of the chamber inlet opening is the area enclosed by this outline.

[0125] The relief channel 42 is formed as a divergence from the suction channel 41, i.e. the relief channel 42 is connected to the delivery chamber via the suction channel 41. The relief channel 42 does not however comprise any point of its own at which it emerges into the delivery chamber. This is shown in FIG. 4 by the fact that the radial boundary surface U of the delivery chamber in FIG. 4 is interrupted only by the chamber inlet opening 40 and the chamber outlet opening 50, and in FIG. 5 by the fact that only the chamber inlet opening 40 and the chamber outlet opening 50 can be seen in the radial boundary surface U in FIG. 5.

[0126] FIG. 6 shows an isometric view of a second example embodiment of the vacuum pump, wherein the relief valve 60 and the main valve 70 are shown in the form of an exploded representation. Except for the main valve 70′ and the relief valve 60′, the vacuum pump of the second example embodiment substantially corresponds to the vacuum pump of the first example embodiment. Differing components of the second example embodiment, i.e. components which are configured differently from the first example embodiment, are marked with an apostrophe for a better overview.

[0127] Since the vacuum pump of the second example embodiment differs from the vacuum pump of the first example embodiment in particular by the relief valve 60′ and the main valve 70′, these will be discussed in more detail in the following.

[0128] The main valve 70′ and the relief valve 60′ are formed as a double reed valve. The main valve 70′ comprises a spring-elastic valve tongue 72′ and an abutment 73′ for the spring-elastic valve tongue 72′. Similarly, the relief valve 60′ comprises a spring-elastic valve tongue 62′ and an abutment 63′. The abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ protrude in a U shape from a common fastening region, i.e. the longitudinal axis of the abutment 73′ of the main valve 70′ and the longitudinal axis of the abutment 63′ of the relief valve 60′ extend in parallel from the common fastening region. The abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ enclose an angle β of 0°, wherein a deviation of at most ±20° is allowable.

[0129] The abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ are formed in one piece with the common fastening region. The abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ are formed together with the common fastening region from sheet metal, in particular by being punched or cut out, wherein the abutment 73′ of the main valve 70′, the abutment 63′ of the relief valve 60′ and the common fastening region exhibit a constant thickness b′ over their entire area.

[0130] In FIG. 9, which shows a plan view onto the vacuum pump of the second example embodiment, it can be seen that the abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ protrude to exactly the same extent from the common fastening region, wherein the abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′ protrude from the common fastening region with an offset with respect to each other in relation to their longitudinal axis.

[0131] This is due to the discharge opening 53 and the relief opening 43 which, as can be seen in FIG. 10, are arranged next to each other in the circumferential direction of the vacuum pump and offset with respect to each other in the axial direction.

[0132] The statements just made apply similarly to the spring-elastic valve tongue 72′ of the main valve 70′ and the spring-elastic valve tongue 62′ of the relief valve 60′, i.e. the spring-elastic valve tongue 62′ of the relief valve 60′ and the spring-elastic valve tongue 72′ of the main valve 70′ protrude from a common fastening region, wherein the spring-elastic valve tongue 62′ of the relief valve 60′ and the spring-elastic valve tongue 72′ of the main valve 70′ are produced in one piece with the common fastening region. The spring-elastic valve tongue 62′ of the relief valve 60′ and the spring-elastic valve tongue 72′ of the main valve 70′ are connected to each other in a U shape via the common fastening region, i.e. the spring-elastic valve tongue 62′ of the relief valve 60′ and the spring-elastic valve tongue 72′ of the main valve 70′ protrude from the common fastening region at an enclosed angle α of 90° with a deviation of at most ±20°.

[0133] The spring-elastic valve tongue 72′ of the main valve 70′ and the spring-elastic valve tongue 62′ of the relief valve 60′ are formed together with the common fastening region from sheet metal, in particular spring sheet metal, by being punched or cut out. The spring-elastic valve tongue 72′ of the main valve 70′ and the spring-elastic valve tongue 62′ of the relief valve 60′, together with the common fastening region, exhibit a constant thickness.

[0134] Contrary to the vacuum pump of the first example embodiment, the abutment 73′ of the main valve 70′ and the abutment 63′ of the relief valve 60′, together with the spring-elastic valve tongue 72′ of the main valve 70′ and the spring-elastic valve tongue 62′ of the relief valve 60′, are connected to the pump housing 30 via their common fastening region by means of two screws.

[0135] FIG. 7 and FIG. 8 show a section through the vacuum pump of the second example embodiment, in a plan view and as an isometric view, with the main valve 70′ and the relief valve 60′ assembled. Together with FIG. 6, the profile of the suction channel 41 and discharge channel 52 can be clearly seen. Even if the profiles of the suction channel 41 and discharge channel 52 in the first example embodiment and second example embodiment do not exactly match, the essential feature of an aspect of the invention remains that the relief channel 42 emerges into the suction channel 41 upstream of the chamber inlet opening 40 when the delivery member 10, 20 rotates in the forward rotational direction. Reference shall therefore be made exclusively to FIGS. 6, 7 and 8 in the following, wherein the statements made also apply to the first example embodiment.

[0136] The relief channel 42 is formed as a blind bore in the pump housing 30, which intersects the suction channel 41, wherein the region in which the relief channel 42 intersects the suction channel 41 forms the channel intersection 44. The channel intersection 44 is formed upstream of the chamber inlet opening 40 in relation to a flow formed when the delivery member 10, 20 rotates in the forward rotational direction, such that the relief channel is only connected to the delivery chamber via the suction channel 41. As can be seen in particular from FIG. 8, the blind bore of the relief channel 42 does not completely penetrate the pump housing 30, i.e. the relief channel 42 comprises a channel base, wherein the channel base can also be formed by a boundary of the suction channel 41.

LIST OF REFERENCE SIGNS

[0137] 10 rotor [0138] 20 rotor vane [0139] 30 housing [0140] 40 chamber inlet opening [0141] 41 suction channel [0142] 42 relief channel [0143] 43 relief opening [0144] 44 canal intersection [0145] 45 reflux valve [0146] 46 suction port [0147] 50 chamber outlet opening [0148] 52 discharge channel [0149] 53 discharge opening [0150] 60 relief valve [0151] 60′ relief valve [0152] 61 valve seat [0153] 61′ valve seat [0154] 62 valve tongue [0155] 62′ valve tongue [0156] 63 abutment [0157] 63′ abutment [0158] 70 main valve [0159] 70′ main valve [0160] 71 valve seat [0161] 71′ valve seat [0162] 72 valve tongue [0163] 72′ valve tongue [0164] 73 abutment [0165] 73′ abutment [0166] b thickness [0167] b′ thickness [0168] d length of the suction channel [0169] U boundary surface of the delivery chamber [0170] W width of the channel inlet opening