Patent Grant
11927190
This application claims benefit of priority from German Patent Application No. 10 2020 111 301.3, filed Apr. 24, 2020. The contents of this application are incorporated herein by reference.
The invention relates to a vacuum pump, in particular a vane cell pump, for supplying a machine assembly, in particular a motor vehicle machine assembly, with negative pressure. In preferred embodiments, the machine assembly is a brake servo of a motor vehicle. The vacuum pump comprises a housing featuring a delivery chamber, wherein the delivery chamber comprises at least one chamber inlet opening and at least one chamber outlet opening for a fluid, preferably a gaseous fluid. When the pump is operating normally, the chamber inlet opening is preferably formed in a low-pressure region of the delivery chamber, and the chamber outlet opening is preferably formed in a high-pressure region of the delivery chamber. The vacuum pump also comprises a delivery member which is mounted such that it can rotate in the delivery chamber, wherein the fluid can be suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in a forward rotational direction. Operating the vacuum pump by rotating the delivery member in the forward rotational direction represents the normal operation of the vacuum pump and/or normal pump operations. The vacuum pump can be connected or is already connected to the machine assembly via a suction port which is connected to the delivery chamber via a suction channel.
Vacuum pumps in motor vehicles, for example for operating brake servos, must response with as little delay as possible and provide the corresponding negative pressure as immediately as possible when negative pressure is needed at a machine assembly. Providing negative pressure to the machine assembly can be of significant relevance to the safety of the motor vehicle, in particular in the case of brake servos. Vacuum pumps must therefore operate reliably and with no susceptibility to outage. In conventionally designed vacuum pumps, this reliability can be disrupted in operating conditions which deviate from normal operations. It can then transpire that the delivery member of vacuum pumps rotates in a reverse rotational direction instead of a forward rotational direction, which corresponds to normal pump operations. This operating state can for example occur in a motor vehicle if it is rolled backwards, with the engine switched off, when being unloaded from a car transporter and is slowed, while still rolling, by engaging the clutch with the engine still switched off. This operating state can be particularly damaging to the vacuum pump, in particular with regard to any lubricating oil present within the delivery chamber, which is for example suctioned by the negative pressure prevailing in the delivery chamber when the pump is switched off. When the pump is suddenly rotated in reverse, this is damaging in that the oil situated in the delivery chamber causes a very high drive torque of the pump, such that the delivery member, for example a vane of the negative pressure pump, can be destroyed or otherwise damaged by being overloaded.
Therefore an aspect of the invention aims to overcome these disadvantages and to design the vacuum pump to be less susceptible to outage and to improve the service life of the pump.
An aspect of the invention relates in particular to a vacuum pump, preferably a vane cell pump, for supplying a machine assembly with negative pressure. The vacuum pump comprises a housing featuring a delivery chamber which comprises a chamber inlet opening and a chamber outlet opening for a fluid, preferably a gaseous fluid. The gaseous fluid can in particular be air. When the delivery member rotates in a forward rotational direction, the chamber inlet opening is preferably formed in a low-pressure region of the delivery chamber which is connected in fluid communication with the machine assembly via a suction port. When the delivery member rotates in the forward rotational direction, the chamber outlet opening by contrast is preferably arranged in a high-pressure region of the delivery chamber and preferably connects it in fluid communication with the environment of the vacuum pump. The chamber inlet opening and/or the chamber outlet opening is/are preferably formed in the radial boundary surface of the delivery chamber.
The vacuum pump comprises a suction channel which emerges into the delivery chamber via the chamber inlet opening and connects the delivery chamber to a suction port. The vacuum pump can be connected directly to the machine assembly via the suction port or indirectly, for example via another feed conduit. The low-pressure region of the delivery chamber is thus connected in fluid communication with the machine assembly via the suction port and the suction channel when the delivery member rotates in the forward rotational direction.
The vacuum pump also comprises a delivery member which is mounted such that it can rotate in the delivery chamber, wherein the fluid, in particular a gaseous fluid such as for example air, 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. The fluid is preferably discharged via a discharge opening which is formed in the housing of the vacuum pump and connected to the chamber outlet opening. The chamber outlet opening is connected in fluid communication with the discharge opening via a discharge channel.
In addition to the delivered gaseous fluid, lubricating oil which is provided in the delivery chamber for lubricating the moving parts and continuously replenished into the delivery chamber is also discharged via the discharge opening. The lubricating oil serves to lubricate the delivery member, in particular the slide bearing of the rotor or delivery member. In vane cell pumps, it is in particular advantageous to also lubricate the radial boundary surface of the delivery chamber by means of a film of oil, such that the tip(s) of the rotor vane(s) can more easily slide along the radial boundary surface of the delivery chamber. The lubricating oil also serves to seal off gaps if there are gaps formed in the delivery chamber or adjoining the delivery chamber. Said lubricating oil is continuously outputted to the environment, while the pump is operating normally, via the chamber outlet opening and the discharge opening connected to the chamber outlet opening via the discharge channel.
In the field of motor vehicle technology, vacuum pumps such as the invention preferably relates to are often attached in or near the oil reservoir, such that the discharged lubricating oil can flow directly back into the reservoir. However, one consequence of this arrangement is often that lubricating oil is additionally suctioned from the reservoir into the delivery chamber, after the vacuum pump has been switched off, due to the negative pressure prevailing in the delivery chamber. When the vacuum pump is re-started, the excess lubricating oil is channeled back into the reservoir again via the discharge opening, such that the drive torque can be significantly reduced.
In preferred embodiments, a main valve prevents fluid from being suctioned through the discharge opening, in particular when the delivery member rotates in a reverse rotational direction, and enables the fluid, in particular the gaseous fluid delivered, to be discharged and lubricating oil to be simultaneously discharged when the delivery member rotates in the forward rotational direction. The main valve is advantageously arranged in the region of the discharge opening, but can also be arranged along the discharge channel. In particularly preferred embodiments, the valve body seat of the main valve encloses the discharge opening.
When the delivery member rotates in the forward rotational direction, the discharge channel preferably extends downstream of the chamber outlet opening as far as the main valve, i.e. the discharge channel connects the delivery chamber in fluid communication with the pump environment via the discharge opening when the delivery member rotates in the forward rotational direction. Alternatively, the delivered fluid can serve to supply another machine assembly with a positive pressure, such that the discharge channel connects the delivery chamber in fluid communication with the corresponding machine assembly via the discharge opening when the delivery member rotates in the forward rotational direction. The fluid in the delivery chamber is preferably drained into the pump environment via the discharge opening when the delivery member rotates in the forward rotational direction.
In particularly preferred embodiments, the main valve is embodied as a reflux valve which opens the discharge channel and in particular the discharge opening when the delivery member rotates in the forward rotational direction and closes the discharge channel and in particular the discharge opening when the delivery member rotates in the reverse rotational direction. The valve body of the main valve can in particular be formed by a spring-elastic valve tongue, for example in the form of a leaf spring, wherein the main valve comprises a valve body seat and an abutment for the valve body. In other words, the main valve can be formed as a reed valve comprising a spring-elastic valve tongue and an abutment for the valve tongue.
Furthermore, a reflux valve protects the machine assembly against fluid, in particular air and/or lubricant, flowing back when the delivery member rotates in the reverse rotational direction. The reflux valve separates the suction channel from the machine assembly when the delivery member rotates in the reverse rotational direction, and opens the suction channel when the delivery member rotates in the forward rotational direction. The reflux valve can be formed in the region of the suction port or along the suction channel. The reflux valve can be arranged in the region of the vacuum pump, in particular in the pump housing, but is preferably formed for example in a feed conduit to the machine assembly or in the region of the machine assembly which is supplied with negative pressure.
In addition to the discharge channel and the suction channel, the pump comprises a relief channel. The relief channel connects the delivery chamber, preferably the low-pressure region of the delivery chamber when the delivery member rotates in the forward rotational direction, to a relief opening of the pump housing. The relief channel connects the delivery chamber to the environment of the vacuum pump via the relief opening. The suction channel extends, preferably within the pump housing, from the chamber inlet opening to the suction port.
Lubricating oil is preferably transported away from the delivery chamber via the relief opening, in particular in operating states deviating from normal operations of the vacuum pump, and outputted to the environment. In particular when the vacuum pump is switched off, lubricating oil can additionally accumulate in the delivery chamber of the vacuum pump, wherein said lubricating oil can be discharged from the delivery chamber via the relief channel and the relief opening connected to the relief channel if the delivery member suddenly rotates in the reverse rotational direction.
A relief valve is formed in the region of the relief channel in order to prevent fluid from being suctioned via the relief opening and the efficacy of the pump thus being reduced. The relief valve is designed to close the relief channel when the delivery member rotates in the forward rotational direction and to open the relief channel when the delivery member rotates in the reverse rotational direction. The relief valve is preferably attached in the region of the relief opening, such that the relief valve closes the relief opening when the delivery member rotates in the forward rotational direction and opens the relief opening when the delivery member rotates in the reverse rotational direction.
The relief channel can then be formed separately from the suction channel in the pump housing. The relief channel preferably emerges into the suction channel of the pump in a channel intersection, i.e. the relief channel preferably extends from the relief opening of the pump housing up to a channel intersection at which the relief channel emerges into the suction channel. The relief channel preferably emerges into the suction channel upstream of the chamber inlet opening in relation to the flow which is established in the suction channel when the delivery member rotates in the forward rotational direction.
The relief channel particularly preferably emerges into the suction channel at a distance from the chamber inlet opening by a length d measured along the suction channel, wherein the length d is measured from the chamber inlet opening along the suction channel in an upstream direction when the delivery member rotates in the forward rotational direction. The relief channel thus emerges into the suction channel in the upstream direction of the chamber inlet opening when the delivery member rotates in the forward rotational direction.
If a reflux valve is provided in the suction channel, the channel intersection at which the relief channel emerges into the suction channel is formed between the reflux valve and the chamber inlet opening. The reflux valve is designed to connect the machine assembly in fluid communication with the delivery chamber when the delivery member rotates in the forward rotational direction and to separate the machine assembly from the delivery chamber when the delivery member rotates in the reverse rotational direction. The relief channel emerges downstream of the reflux valve and upstream of the chamber inlet opening in relation to the flow established in the suction channel when the delivery member rotates in the forward rotational direction.
The length d of the suction channel from the chamber inlet opening up to the channel intersection at which the relief channel emerges into the suction channel is advantageously at least as large as a smallest width W of the chamber inlet opening, i.e. the length d of the suction channel from the chamber inlet opening up to the channel intersection preferably corresponds to at least the smallest width W of the chamber inlet opening. The length d of the suction channel from the chamber inlet opening up to the channel intersection particularly preferably corresponds to at least twice the smallest width W of the chamber inlet opening or three times the smallest width W of the chamber inlet opening.
The smallest width W of the chamber inlet opening is understood to mean the smallest extent of the chamber inlet opening when the radial boundary surface of the delivery chamber is unfurled. The chamber inlet opening can thus extend to different extents in the axial direction and in the circumferential direction of the radial boundary surface, wherein the smallest width W denotes its smallest extent, irrespective of its direction.
Since the delivery chamber is substantially formed by a cylindrical cavity in the housing, the unfurled radial boundary surface, in which the chamber inlet opening is advantageously formed, corresponds to the surface area of the cylindrical cavity. If the chamber inlet opening is circular, the smallest width W of the chamber inlet opening would correspond to the diameter of the chamber inlet opening. The chamber inlet opening is advantageously formed elliptically.
It should be noted that the geometry of the chamber inlet opening does not allow any conclusions to be drawn about the flow cross-section of the suction channel. The suction channel can for example be formed by a circular-cylindrical bore which extends along a secant which intersects the delivery chamber. This results in an elliptical chamber inlet opening in the unfurled radial boundary surface of the delivery chamber.
In preferred embodiments, the flow resistance of the relief channel is greater than the flow resistance of the suction channel. This can for example be achieved by the mean flow cross-section of the suction channel being larger than the mean flow cross-section of the relief channel. The mean flow cross-section is understood to mean the arithmetic mean of the individual flow cross-sections along the corresponding channel. In preferred embodiments, the relief channel exhibits a constant flow cross-section, such that the mean flow cross-section is equal to the flow cross-section at any point in the relief channel. The flow cross-section of the channel intersection at which the relief channel emerges into the suction channel is preferably smaller than the mean flow cross-section of the suction channel in the region of the channel intersection.
The relief channel extends from the channel intersection, at which the relief channel emerges into the suction channel, up to a relief opening, wherein the relief opening is formed in the upstream direction of the channel intersection when the delivery member rotates in the forward rotational direction. The relief channel preferably exhibits a constant flow cross-section over its entire length. The relief channel particularly preferably exhibits a circular flow cross-section.
The relief opening and the channel intersection at which the relief channel emerges into the suction channel are preferably equal in size. The length of the relief channel corresponds to the length of the relief channel between the channel intersection, at which the relief channel emerges into the suction channel, and the relief opening. The relief channel preferably exhibits a linear profile over its length, i.e. the relief channel preferably corresponds to the projection of the relief opening along a straight line of length.
In preferred embodiments, the relief channel is formed as a blind bore which intersects or crosses the suction channel, i.e. the relief channel does not completely penetrate the pump housing and in particular does not intersect the radial boundary surface of the delivery chamber, wherein the base of the blind bore can be formed by a boundary wall of the suction channel.
In preferred embodiments, the mean flow cross-section of the relief channel and the mean flow cross-section of the discharge channel differ from each other, wherein the mean flow cross-section is understood to mean the arithmetic mean of the individual flow cross-sections along the corresponding channel. In particularly preferred embodiments, the mean flow cross-section of the discharge channel is larger than the mean flow cross-section of the relief channel. In particular, the mean flow cross-section of the discharge channel preferably exhibits at least one and a half times the mean flow cross-section of the relief channel.
In addition to the discharge opening of the discharge channel and the relief opening of the relief channel, at least one of the relief channel and the discharge channel can comprise a pressure equalization opening via which the delivery chamber is connected, preferably permanently, in fluid communication with the environment. The pressure equalization opening serves to equalize the pressure in the delivery chamber when the vacuum pump is at a stop, such that the negative pressure in the delivery chamber can be dissipated, wherein the flow resistance of the pressure equalization opening is at least twice the flow resistance of the relief channel and/or discharge channel. The pressure equalization opening is preferably formed in the region of the relief valve and/or the main valve.
In preferred embodiments, the relief valve is embodied as a reflux valve which closes the relief channel when the delivery member rotates in the forward rotational direction and opens the relief channel when the delivery member rotates in the reverse rotational direction. The relief valve is preferably formed in the region of the relief opening, such that the relief valve closes the relief opening when the delivery member rotates in the forward rotational direction and opens it when the delivery member rotates in the reverse rotational direction.
Preferably, the relief opening simultaneously forms the valve opening of the relief valve. The valve body of the relief valve can in particular be formed by a spring-elastic valve tongue, for example in the form of a leaf spring. The relief valve also comprises a valve body seat and an abutment for the valve body. In other words, the relief valve can be formed as a reed valve comprising a spring-elastic valve tongue and an abutment for the valve tongue. In preferred embodiments, the valve body seat is formed by the pump housing which surrounds the relief opening, i.e. the valve body seat of the relief valve preferably encloses the relief opening in the circumferential direction.
The relief opening and the discharge opening are preferably arranged next to each other in the circumferential direction of the pump housing. Preferably, the discharge opening can be closed by the main valve, and the relief opening can be closed by the relief valve. In particularly advantageous embodiments, the relief opening is formed in front of the discharge opening, in the forward rotational direction of the delivery member, in the pump housing.
The abutment of the relief valve and the abutment of the main valve are advantageously connected to each other in a common fastening region, wherein the fastening region is understood to mean the region of the abutment via which the abutment is connected to the housing. Screws or blind rivets can for example serve as fastening elements. It is however also conceivable for the fastening region of the abutment to be joined to the housing in a material fit, for example by welding or soldering. Adhesive connections are also conceivable.
The abutment of the relief valve and the abutment of the main valve are preferably connected to each other in an L shape in a plan view via the common fastening region, i.e. the abutment of the relief valve and the abutment of the main valve preferably protrude from a common fastening region at an enclosed angle β.
The enclosed angle β is then preferably less than 180°, in particular less than 150° and particularly preferably less than 120°. The abutment of the relief valve and the abutment of the main valve can protrude in parallel from the common fastening region, such that the angle β enclosed by the abutment of the main valve and the abutment of the relief valve measures approximately 0° with a tolerance of up to 20°. In this case, the abutment of the relief valve and the abutment of the main valve are connected to each other in a U shape in a plan view via the common fastening region. More preferably, the enclosed angle β is more than 40° or more than 60°; particularly preferably, the abutment of the relief valve and the abutment of the main valve enclose a right angle. The angle β particularly preferably measures 90° with a tolerance of at most ±20°.
The abutment of the main valve and the abutment of the relief valve can be produced in one piece. The abutment of the main valve and the abutment of the relief valve can then for example be punched or cut from sheet metal. The abutment of the main valve, the abutment of the relief valve and the common fastening region preferably exhibit a constant thickness b over the entire region. The thickness b of the abutment of the relief valve and the thickness b of the abutment of the main valve preferably measure less than 5 mm, particularly preferably less than 2 mm.
The abutment of the main valve and the abutment of the relief valve can lie in a common plane with the common fastening region, but preferably protrude from the plane formed by the common fastening region at an angle of less than 90°, in particular less than 45°, i.e. the common fastening region and the abutment of the main valve enclose a common angle of more than 90°, in particular more than 135°. The common fastening region and the abutment of the relief valve likewise enclose a common angle of more than 90°, in particular more than 135°.
The relief valve and the main valve are formed as reed valves, in particular double reed valves, i.e. the valve tongue of the relief valve and the valve tongue of the main valve are connected to each other, preferably in a L shape or U shape in a plan view, via a common fastening region, i.e. the valve tongue of the relief valve and the valve tongue of the main valve preferably protrude from a common fastening region at an enclosed angle α.
The enclosed angle α is then preferably less than 180°, in particular less than 150° and particularly preferably less than 120°. The valve tongue of the relief valve and the valve tongue of the main valve can protrude in parallel from the common fastening region, such that the angle α enclosed by the valve tongue of the main valve and the valve tongue of the relief valve measures approximately 0° with a tolerance of up to 20°. In this embodiment, the valve tongue of the relief valve and the valve tongue of the main valve are connected to each other in a U shape in a plan view via the common fastening region. More preferably, the enclosed angle α is more than 40° or more than 60°; particularly preferably, the valve tongue of the relief valve and the valve tongue of the main valve enclose a right angle. The angle α particularly preferably measures 90° with a tolerance of at most ±20°. In this example embodiment, the valve tongue of the relief valve and the valve tongue of the main valve are connected to each other in an L shape in a plan view via the common fastening region.
The valve tongue of the main valve and the valve tongue of the relief valve are preferably produced in one piece. The valve tongue of the relief valve and the valve tongue of the main valve can in particular be formed in one piece, for example punched or cut, from sheet metal, preferably spring sheet metal, wherein the thickness b of the valve tongue of the relief valve, the thickness of the valve tongue of the main valve and the thickness of the common fastening region are preferably equal in size, preferably less than 1 mm and particularly preferably less than 0.5 mm.
The valve tongue of the relief valve and the valve tongue of the main valve lie in a plane with the common fastening region, wherein the valve tongue of the relief valve and the valve tongue of the main valve can be spring-elastically deflected out of the common plane. The deflecting force required to deflect the valve tongue of the main valve and the valve tongue of the relief valve is dimensioned such that the fluid flow established by the vacuum pump when the delivery member rotates in the forward rotational direction and when the delivery member rotates in the reverse rotational direction can deflect the valve tongue of the main valve and the valve tongue of the relief valve.
The main valve and the relief valve operate oppositely, i.e. while the main valve is in an opening position when the delivery member rotates in the forward rotational direction, the relief valve is in a closing position when the delivery member rotates in the forward rotational direction.
The main valve and the relief valve are advantageously formed as double reed valves, i.e. the abutment of the main valve, the abutment of the relief valve, the spring-elastic valve tongue of the main valve and the spring-elastic valve tongue of the relief valve are connected to the housing of the pump via a common fastening element, in particular a fastening screw or a blind rivet. In advantageous embodiments, the abutment of the main valve and the abutment of the relief valve are formed in one piece and overlap the valve tongue of the main valve and the valve tongue of the relief valve, which are likewise formed in one piece, in a radial plan view when installed, i.e. the integrally formed abutments of the main valve and relief valve are the same size or larger than the integrally formed valve tongues of the main valve and relief valve.
Features of the invention are also described in the aspects formulated below. The aspects are worded in the manner of claims and can substitute for them. Features disclosed in the aspects can also supplement and/or qualify the claims, indicate alternatives with respect to individual features and/or broaden claim features. Bracketed reference signs refer to example embodiments of the invention illustrated below in figures. They do not restrict the features described in the aspects to their literal sense as such, but do conversely indicate preferred ways of implementing the respective feature.
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:
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.
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.
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.
As can be seen from
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.
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.
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.
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.
As can be seen in
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°.
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.
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.
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
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.
The suction channel 41 is indicated in
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
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.
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.
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
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.
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
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.
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.
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.
In
This is due to the discharge opening 53 and the relief opening 43 which, as can be seen in
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°.
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.
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.
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
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 111 301.3 | Apr 2020 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20100000207 | Heaps | Jan 2010 | A1 |
| 20100239440 | Heaps | Sep 2010 | A1 |
| 20130022485 | Hunter | Jan 2013 | A1 |
| 20180238331 | Hammer | Aug 2018 | A1 |
| 20190170141 | Ott et al. | Jun 2019 | A1 |
| 20200116150 | Heaps | Apr 2020 | A1 |
| 20200309126 | Hattori | Oct 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 102010055125 | Jun 2012 | DE |
| 102016122903 | May 2018 | DE |
| 102017128972 | Jun 2019 | DE |
| 0255920 | Feb 1988 | EP |
| 2853747 | Apr 2015 | EP |
| WO-2004044431 | May 2004 | WO |
| WO-2008009251 | Jan 2008 | WO |
| WO-2010145633 | Dec 2010 | WO |
| 2018224117 | Dec 2018 | WO |
| Entry |
|---|
| German Search Report issued in German Application No. 10 2020 111 301.3, dated Feb. 22, 2021, 7 pages. |
| German Examination Report for German Application No. 10 2020 111 301.3, dated Aug. 30, 2022, with translation, 11 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20210332820 A1 | Oct 2021 | US |
