CN111412143A - Low-noise electronic vacuum pump with built-in one-way non-return structure - Google Patents

Abstract

The invention relates to a low-noise electronic vacuum pump with a built-in one-way check structure, which is characterized in that a path of airflow in an air inlet chamber is bent and prolonged by a path extension check piece, so that a silencing path is prolonged, and the silencing effect is enhanced. Based on the matching of the path extension check piece and the elastic diaphragm, a built-in one-way check structure is formed, the one-way check function is realized, and the vacuum pump can be effectively prevented from sucking back foreign matters such as liquid, particles and the like. When the vacuum pump works to pump air, the elastic diaphragm expands and bulges towards the buffer chamber under the action of air flow impact, and the air flow path is communicated; when the vacuum pump stops working, the elastic diaphragm is tightly attached to the bead rib, the airflow path is cut off, and the non-return effect is realized. The invention not only prolongs the noise transmission path, but also enables the section of the noise transmission path to be suddenly changed, realizes double noise reduction by two modes in principle, realizes multiple noise reduction by various structures in structure, and finally reduces the working noise of the vacuum pump to the maximum extent.

Description

Low-noise electronic vacuum pump with built-in one-way non-return structure

Technical Field

The invention relates to an electronic vacuum pump in the field of automobiles, in particular to a low-noise electronic vacuum pump with a built-in one-way non-return structure.

Background

With the increasing requirements of legislation on fuel consumption and carbon emissions of automobiles, small-displacement turbocharged engines and electric automobiles become the choice of more and more automobile manufacturers.

The vacuum boosting brake system of the automobile with the small-displacement turbocharged engine has the problem that the driving safety is affected due to the fact that the vacuum degree is insufficient under certain working conditions. At the moment, the electronic vacuum pump can provide an additional vacuum source for the electronic vacuum pump, so that the normal work of the vacuum booster is ensured, and the driving safety is ensured.

An electric vehicle equipped with a vacuum-assisted brake system needs an additional device to provide vacuum specially because no engine provides vacuum, and an electronic vacuum pump is a good choice.

However, as shown in fig. 1 and 2, the pre-silencing mechanism of the prior art electronic vacuum pump is a cylindrical rubber sleeve, the airflow directly impacts the top silencing cover after exiting from the pump chamber, and noise directly penetrates through the silencing cover and enters the external atmosphere, so that the problem of high noise exists.

Moreover, when the vacuum pump stops working, the negative pressure generated inside the air outlet sucks water and impurities in the humid air, so that noise is generated, a large amount of water is condensed or impurities exist in the pump chamber, and if water or impurities exist in the pump chamber, the water or impurities can increase the running resistance of the blades when the blades run at high speed, so that the blades are easy to break.

Chinese patent application 201680068579.2 discloses a vacuum pump with a muffler and a check valve, the pre-muffler element having an integrally formed projection directed toward the bottom plate and forming in the middle a projection directed toward the bottom plate with an air passage passing through the projection. Wherein the projection is arranged spaced apart from the end-face floor during operation of the vacuum pump, and wherein the projection, when the vacuum pump is shut down, comes to bear against the end face as a result of the elastic deformation of the pre-muffler element, so that the air passage is closed and the function of a non-return valve is established.

However, in the technical scheme of the invention patent application, the silencing path in the silencing device is short, the formed chambers are few, and the silencing is incomplete. And the gas circuit in the noise eliminator is the straight line, can't form between the hole and stop, can't prevent water and impurity that get into in the vacuum pump from being inhaled the pump chamber, if there is water or impurity in the pump chamber, when the blade is in high-speed operation, these water or impurity can increase blade running resistance, make the blade cracked easily.

Chinese patent application 201610986715.8 discloses a low-noise electronic vacuum pump for vehicles, which forms a plurality of chambers through a silencing piece to achieve the purpose of silencing. However, the silencing piece can not realize the one-way non-return function and can not prevent the problem of water or impurities from being sucked.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a low-noise electronic vacuum pump with a built-in one-way check structure, which can effectively eliminate noise and prevent water and impurities from being sucked into a pump chamber through the built-in one-way check structure.

The technical scheme of the invention is as follows:

a low-noise electronic vacuum pump with a built-in one-way non-return structure is characterized in that a silencing sleeve is hermetically arranged between a silencing cover and a pump chamber cover plate and is separated into an air inlet chamber and a buffer chamber through an elastic diaphragm, a plurality of air passing holes are formed in the elastic diaphragm, a path extension non-return piece is arranged in the air inlet chamber, and a linear path between the pump chamber cover plate and the air passing holes forms an extended bent air path through the path extension non-return piece; when the vacuum pump works, the elastic diaphragm is forced to deform by the airflow, the bent air passage formed by the path extension check piece is communicated, and the airflow reaches the air passing hole through the bent air passage; when the vacuum pump stops working, the elastic diaphragm deforms due to the difference between the internal pressure and the external pressure of the elastic diaphragm, and the bent air path formed by the path extension check piece is blocked, so that the check is realized.

Preferably, the path extension non-return piece comprises a supporting plate, the periphery of the supporting plate is in sealing fit with the inner side of the air inlet chamber of the noise reduction sleeve, the supporting plate and the air passing hole of the elastic diaphragm are provided with air holes in a staggered mode, and the bent air path is bent towards the air passing hole at the positions of the air holes.

Preferably, one surface of the support plate facing the elastic diaphragm is provided with a raised bead rib which surrounds the vent hole; when the elastic diaphragm is tightly attached to the bead convex rib, the bent gas path is blocked.

Preferably, a raised supporting wall is arranged on one surface, facing the elastic diaphragm, of the supporting plate close to the edge, the supporting wall abuts against the elastic diaphragm, clamping ribs transversely extend out of the outer wall of the supporting wall, and interference fit is formed between the clamping ribs and the inner wall of the air inlet chamber.

Preferably, the support plate is provided with a plurality of protruding support blocks on a surface facing the pump chamber cover plate, and the support plate is kept spaced from the pump chamber cover plate by the support blocks.

Preferably, the support blocks of the T-shaped structures are radially and uniformly distributed around the vent holes, the straight sections of the support blocks of the T-shaped structures face the vent holes, and the transverse sections of the support blocks face the edges of the support plates.

Preferably, the elastic diaphragm forms a curved surface toward the vent hole in a natural state.

Preferably, the thickness of the elastic diaphragm is smaller than the thickness of the side wall of the air inlet chamber, and the thickness of the side wall of the air inlet chamber is smaller than the thickness of the inner wall of the buffer chamber.

Preferably, the inner wall of the end part of the air inlet chamber facing the pump chamber cover plate is provided with a chamfer to form a bell mouth; the outer wall of the end part of the air chamber facing the pump chamber cover plate is provided with a chamfer.

Preferably, at least one layer of annular silencing groove is arranged at the position, opposite to the elastic diaphragm, of the inner top surface of the silencing cover, and adjacent annular silencing grooves are communicated through a plurality of air passing notches; the annular silencing groove is formed by surrounding a plurality of layers of annular walls protruding towards the elastic diaphragm from the inner top surface of the silencing cover, and a plurality of air passing notches are formed in the annular walls; the buffer chamber is in interference fit with the mounting convex ring of the silencing cover and is connected in a sleeved manner; an air passing port is arranged between the buffer chamber and the mounting convex ring, and the air flow is extruded out of the silencing sleeve through the annular silencing groove and the air passing port.

Preferably, the mounting convex ring is provided with a plurality of transversely inwards concave abdicating concave surfaces, and gaps between the abdicating concave surfaces and the side wall of the buffer chamber form air passing ports; the outer wall of the silencing sleeve transversely extends to form a separating wing edge, a lower pressing convex ring is arranged at the position, opposite to the separating wing edge, of the inner top surface of the silencing cover, and the lower pressing convex ring abuts against the separating wing edge; the pressing convex ring is provided with an air leakage gap; after the airflow is extruded and flows out of the silencing sleeve, the airflow is extruded and flows out through the air leakage notch.

The invention has the following beneficial effects:

the low-noise electronic vacuum pump with the built-in one-way check structure has the advantages that the path of the airflow in the air inlet chamber is bent and prolonged by the path extension check piece, so that the silencing path is prolonged, and the silencing effect is enhanced. Route extension non return spare is through setting up bellied bead rib in the backup pad, and then forms two buffer chamber on the air current route in the air inlet, through buffer chamber's buffering, further strengthens noise cancelling effect. Therefore, through the structural design of the path extension check piece, the dual noise reduction effect is realized, and the working noise of the vacuum pump is reduced.

Based on the matching of the path extension check piece and the elastic diaphragm, a built-in one-way check structure is formed, the one-way check function is realized, and the vacuum pump can be effectively prevented from sucking back foreign matters such as liquid, particles and the like. When the vacuum pump works to pump air, the elastic diaphragm expands and bulges towards the buffer chamber under the action of air flow impact, the bead rib is opened, and the air flow path is conducted; meanwhile, the deformation of the elastic diaphragm can absorb the impact of the airflow, so that the elastic diaphragm has a buffering effect on the airflow and effectively reduces the noise of the airflow. When the vacuum pump stops working, the elastic diaphragm is tightly attached to the bead convex rib, the airflow path is cut off, the non-return effect is realized, the one-way non-return structure is formed, and the vacuum pump is effectively prevented from suck backwards.

The annular silencing groove of the silencing cover enables airflow to enter the buffer chamber and then to be extruded and flow out through the air gap, the air passing port, the air leakage gap and other positions, and sound waves transmitted along the path can be reflected by utilizing the sudden change of the section of the sound transmission path in the extrusion and flow-out process, so that the working noise of the vacuum pump is reduced.

According to the invention, the characteristic structures of the non-return piece, the silencing sleeve and the silencing cover are extended on the airflow path, so that the noise transmission path is extended, the section of the noise transmission path is suddenly changed, dual noise reduction is realized in two ways in principle, multiple noise reduction is realized structurally through various structures, and finally the working noise of the vacuum pump is reduced to the maximum extent.

Drawings

FIG. 1 is a schematic structural view of a prior art pre-silencing mechanism;

FIG. 2 is a schematic gas flow diagram of a prior art electronic vacuum pump;

FIG. 3 is a structural sectional view (working state) of the present invention;

FIG. 4 is a structural cross-sectional view (out-of-service) of the present invention;

FIG. 5 is a first schematic view of a path extending check;

FIG. 6 is a structural cross-sectional view of the path extension check;

FIG. 7 is a second schematic view of the path extension check;

FIG. 8 is a schematic view of the structure of the noise dampening sleeve;

FIG. 9 is a structural cross-sectional view of the noise dampening sleeve;

FIG. 10 is a schematic view of the construction of the noise damping cover;

FIG. 11 is a structural sectional view of the noise-canceling cover;

in the figure: 10 is a silencing cover, 11 is an annular silencing groove, 111 is an air passing notch, 12 is an annular wall, 13 is an installation convex ring, 131 is a yielding concave surface, 14 is an air passing hole, 15 is a pressing convex ring, 151 is an air releasing notch, 20 is a silencing sleeve, 21 is an air inlet chamber, 211 is a bell mouth, 22 is a buffer chamber, 23 is an elastic diaphragm, 231 is an air passing hole, 232 is a cambered surface, 24 is a separating wing edge, 30 is a path extending check member, 31 is an air passing hole, 32 is a bead convex rib, 33 is a supporting wall, 34 is a clamping rib, 35 is a supporting block, 351 is a straight section, 352 is a transverse section, 36 is a buffer groove, 37 is a guide inclined plane, 38 is a supporting plate, 40 is a pump chamber cover plate, 51 is a first chamber, 52 is a second chamber, 53 is a third chamber, 54 is a fourth chamber, and 55 is a fifth chamber.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides a low-noise electronic vacuum pump with a built-in one-way non-return structure, aiming at solving the defects of poor noise reduction effect, the need of additionally arranging a check valve and the like in the prior art, and realizing multiple noise reduction from multiple directions such as technical principles, structural design and the like, and further forming the built-in one-way non-return structure in the vacuum pump by realizing one-way non-return on a front silencing mechanism.

As shown in fig. 3 and 4, the low-noise electronic vacuum pump with a built-in one-way check structure of the invention mainly realizes noise reduction and one-way check through the cooperation of the front silencing mechanism and the silencing cover 10. The front silencing mechanism mainly comprises a silencing sleeve 20 and a path extension check piece 30, and a built-in one-way check structure is further formed by matching the silencing sleeve 20 and the path extension check piece 30. In the invention, a silencing sleeve 20 is hermetically arranged between a silencing cover 10 and a pump chamber cover plate 40, the silencing sleeve 20 is separated into an air inlet chamber 21 and a buffer chamber 22 through an elastic diaphragm 23, and the elastic diaphragm 23 is provided with a plurality of air passing holes 231. The path extension check 30 is provided in the intake chamber 21, and a straight path between the pump chamber cover plate 40 and the air passing hole 231 forms an extended zigzag air path through the path extension check 30. Theoretically, the air flow between the holes is a straight path, and further, the noise propagation path is shortest, and the working noise is greatest. The present invention extends the noise propagation path between the air vent 231 and the pump chamber cover plate 40 by the path extension check 30; and the elastic diaphragm 23 of the silencing sleeve 20 is matched with the path extension check piece 30 to control the on-off of the airflow path, so that the unidirectional check is realized. When the vacuum pump works, the elastic diaphragm 23 is forced to deform by the airflow, the bent air passage formed by the path extension check piece 30 is communicated, and the airflow reaches the air passing hole 231 through the bent air passage; when the vacuum pump stops working, the elastic diaphragm 23 deforms due to the difference between the internal pressure and the external pressure of the elastic diaphragm 23, and the bent air passage formed by the path extension check piece 30 is blocked, so that the check is realized.

In this embodiment, the path extension check member 30 is longitudinally separated in the air inlet chamber 21 by a transverse structure, so as to realize bending extension of the air flow path, and the air inlet chamber 21 is separated into at least two chambers as a buffer chamber, so as to realize abrupt change of the cross section of the noise propagation path, thereby achieving the purpose of reducing noise. As shown in fig. 5, 6 and 7, the path extension check 30 includes a support plate 38 transversely disposed in the air inlet chamber 21, the periphery of the support plate 38 is hermetically attached to the inner side of the air inlet chamber 21 of the sound deadening sleeve 20, the support plate 38 and the air passing hole 231 of the elastic diaphragm 23 are provided with air passing holes 31 in a staggered manner, and the zigzag air path is bent toward the air passing hole 231 at the positions of the air passing holes 31; when the vacuum pump stops working, the elastic diaphragm 23 closes the vent hole 31, and the zigzag air passage is blocked. In this embodiment, the air inlet chamber 21 is longitudinally divided by the support plate 38, and then the two chambers are communicated with each other through the vent holes 31 on the support plate 38. Since the elastic diaphragm 23 can close the vent hole 31, obviously, the air passing hole 231 on the elastic diaphragm 23 is not disposed at a position opposite to the vent hole 31, and further, as shown in fig. 3 and 4, the air flow path between the vent hole 31 and the air passing hole 231 has a certain distance of transverse span due to transverse displacement between the vent hole 31 and the air passing hole 231. The air flow paths in the intake chamber 21 are from the pump chamber cover plate 40 to the vent hole 31, and from the vent hole 31 to the air passing hole 231, and are respectively longitudinally extended and transversely extended, and the connection between the longitudinally extended air path and the transversely extended air path is the zigzag air path.

In order to prevent the elastic diaphragm 23 from affecting the formation of the cavity above the support plate 38 when the vent hole 31 is closed, a convex bead 32 is arranged on the surface of the support plate 38 facing the elastic diaphragm 23, and the bead 32 surrounds the vent hole 31; when the elastic diaphragm 23 is tightly attached to the bead rib 32, the bent air passage is blocked. Meanwhile, because the bead ribs 32 have a certain height, under the supporting and limiting effect of the bead ribs 32, the elastic diaphragm 23 is prevented from being attached to the supporting plate 38 in a large area when being deformed toward the supporting plate 38, so that the formation of the cavity above the supporting plate 38 is facilitated, and the size of the cavity above the supporting plate 38 is ensured.

In this embodiment, a protruding supporting wall 33 is disposed on a side of the supporting plate 38 facing the elastic diaphragm 23, the side being close to the edge, and the supporting wall 33 abuts against the elastic diaphragm 23, so that the supporting plate 38 faces upward to form a stable support. In practice, the support plate 38 may have a contour corresponding to the inner contour of the intake chamber 21, and the support wall 33 may be attached to the edge of the elastic diaphragm 23 facing the intake chamber 21 for support. The resilient diaphragm 23 is most strong at this location and is able to more stably provide support for the path extension check 30, ensuring stability of the path extension check 30 disposed within the intake chamber 21. Meanwhile, the bead 32 and the support wall 33 enclose a buffer groove 36 surrounding the vent hole 31, ensuring the formation of a buffer chamber above the support plate 38.

In order to ensure the stable, stable and sealed connection between the supporting plate 38 and the side wall of the air inlet chamber 21, a clamping rib 34 extends transversely from the outer wall of the supporting wall 33, and the clamping rib 34 forms an interference fit with the inner wall of the air inlet chamber 21. Meanwhile, in order to facilitate the installation of the path-extension check 30 into the intake chamber 21, a side of the snap-fit rib 34 (or the snap-fit rib 34 and the support wall 33) facing the installation direction is provided with a guide slope 37. Correspondingly, the inner wall of the end of the intake chamber 21 facing the pump chamber cover 40 is chamfered to form a bell-mouth 211. The flared mouth 211 is in beveled engagement with the guide bevel 37 to further enhance the ease of installation of the path extension check 30. The bell-mouth 211 can increase the range of the intake chamber 21 covering the pump chamber cover 40. The outer wall of the end part of the air inlet chamber 21 facing the pump chamber cover plate 40 is also provided with a chamfer, so that a larger yielding space can be provided for screws on the pump chamber cover plate 40, the structural design is convenient, and the position layout of related parts on the surface of the pump chamber cover plate 40 is convenient.

The size of the interference fit formed by the clamping ribs 34 is slightly larger than the inner size of the air inlet chamber 21, the outer sizes of the supporting wall 33 and the supporting plate 38 are slightly smaller than the inner size of the air inlet chamber 21, and the silencing sleeve 20 cannot be deformed excessively on the basis of ensuring the interference seal fit between the clamping ribs 34 and the silencing sleeve 20. If the silencing sleeve 20 is deformed excessively, the lower edge of the air inlet chamber 21 cannot form a seal with the pump chamber cover plate 40, and then the air flow directly flows to the space between the pump chamber cover plate 40 and the silencing sleeve 20 through the air outlet hole in the pump chamber cover plate 40 and the non-seal connecting position between the pump chamber cover plate 40 and the air inlet chamber 21, and finally the front silencing mechanism cannot play a silencing role.

In order to ensure that a chamber is formed below the support plate 38, noise reduction is achieved, and smooth flow through the vent hole 31 is ensured after the air flow flows out from the pump chamber. In this embodiment, a plurality of protruding support blocks 35 are provided on a surface of the support plate 38 facing the pump chamber cover plate 40, and the support plate 38 is kept spaced from the pump chamber cover plate 40 by the support blocks 35. Since the supporting block 35 has a certain height, when the supporting block 35 contacts the pump chamber cover plate 40, the supporting plate 38 can still be kept away from the pump chamber cover plate 40 at the position of the vent hole 31 for the air flow to pass through.

The present embodiment can also functionally multiplex the supporting block 35, that is, implement a structure having a drainage function. In this embodiment, the supporting blocks 35 are arranged in a "T" shape, the supporting blocks 35 in the "T" shape are radially and uniformly arranged around the ventilation holes 31, the straight sections 351 of the supporting blocks 35 in the "T" shape face the ventilation holes 31, and the horizontal sections 352 face the edge of the supporting plate 38. That is, the horizontal section 352 is enclosed into a broken ring shape at a side close to the edge of the supporting plate 38, and the straight section 351 divides the space enclosed by the horizontal section 352 into a plurality of spaced areas, so as to further extend the airflow path and assist in improving the noise reduction effect.

In order to obtain a more effective and stable one-way check effect, as shown in fig. 8 and 9, in a natural state, the elastic diaphragm 23 forms a curved surface 232 toward the vent hole 31. In this embodiment, the elastic diaphragm 23 is substantially planar, and a concave arc 232 with a slight arc is formed in a certain range of the area facing the vent hole 31 toward the vent hole, so that when the vacuum pump is switched from a working state to a stop working state and a pressure difference is generated between the inlet chamber 21 and the buffer chamber 22, the elastic diaphragm 23 can be ensured to seal the bead 32. Meanwhile, in order to ensure that the elastic diaphragm 23 is difficult to deform due to freezing caused by too low ambient temperature, when the vacuum pump is in an initial working state, the airflow path is turned on, and the elastic diaphragm 23 may be implemented as: the bead 32 is not sealed in a natural state. For application scenarios where the environmental conditions do not exceed the physical limits of the elastic diaphragm 23, the elastic diaphragm 23 may be set to: the bead 32 is either sealed or unsealed in a natural state.

In this embodiment, the thickness of the elastic diaphragm 23 is smaller than the thickness of the side wall of the air inlet chamber 21, and the thickness of the side wall of the air inlet chamber 21 is smaller than the thickness of the inner wall of the buffer chamber 22; preferably, the thickness of the side wall of the buffer chamber 22 is greater than 1 time the thickness of the side wall of the intake chamber 21. So as to balance the overall strength of the silencing sleeve 20 and the deformation performance of the elastic diaphragm 23 and avoid the situation that the side wall of the air inlet chamber 21 or the buffer chamber 22 is too thin, the supporting strength is weak and the installation cannot be stable; meanwhile, the situation that the elastic diaphragm 23 is too thick and cannot generate expansion deformation or the expansion deformation degree is low, and an ideal noise reduction effect cannot be achieved is avoided.

Theoretically, the air inlet chamber 21 and the buffer chamber 22 of the silencing cover 20 need to be in sealing connection with the silencing cover 10 and the pump chamber cover plate 40 to ensure air tightness. In this embodiment, the buffer chamber 22 is in interference fit with the mounting convex ring 13 of the noise reduction cover 10, and is connected in a sleeved manner. As shown in fig. 10 and 11, at least one layer of annular silencing grooves 11 is arranged at the position of the inner top surface of the silencing cover 10 opposite to the elastic diaphragm 23, and the adjacent annular silencing grooves 11 are communicated through a plurality of air passing gaps 111. The annular silencing groove 11 is enclosed by a plurality of layers of annular walls 12 protruding towards the elastic diaphragm 23 from the inner top surface of the silencing cover 10, and a plurality of air passing gaps 111 are formed in the annular walls 12. The annular silencing groove 11 can guide airflow and prolong a noise propagation path; the air passing notch 111 can make the section of the noise propagation path suddenly change, and further reduce the operation noise of the vacuum pump.

An air through port 14 is arranged between the buffer chamber 22 and the mounting convex ring 13, and the air flow is extruded out of the silencing sleeve 20 through the annular silencing groove 11 and the air through port 14. In this embodiment, the mounting convex ring 13 is provided with a plurality of laterally inwardly recessed receding concave surfaces 131, and the gap between the receding concave surfaces 131 and the side wall of the buffer chamber 22 forms the air passing opening 14. The air vent 14 can also be formed by other structures, for example, the buffer chamber 22 and the mounting convex ring 13 form a complete sealing connection with the periphery, and a through hole is arranged at the position of the mounting convex ring 13 above the buffer chamber 22 to be used as the air vent 14, so that the extrusion and outflow of the air flow can also be realized.

In order to form one more buffer chamber, the outer wall of the silencing sleeve 20 is transversely extended with a separating wing edge 24, a lower pressing convex ring 15 is arranged at the position of the inner top surface of the silencing cover 10 opposite to the separating wing edge 24, the lower pressing convex ring 15 is abutted against the separating wing edge 24, and further, the space outside the silencing sleeve 20 and inside the silencing cover 10 is divided into two spaces. The pressing convex ring 15 is provided with an air leakage gap 151; after the airflow is extruded and flows out of the silencing sleeve 20, the airflow is extruded and flows out through the air release notch 151.

The embodiment of the invention forms five buffer chambers in a conformal way, which are respectively as follows: a first chamber 51 between the support plate 38 and the pump chamber cover plate 40, a second chamber 52 between the buffer groove 36 of the support plate 38 and the elastic diaphragm 23, a third chamber 53 between the elastic diaphragm 23 and the muffler cover 10, a fourth chamber 54 between the mounting collar 13, the partition flange 24 and the lower pressing collar 15, and a fifth chamber 55 in the muffler cover 10 outside the lower pressing collar 15 and the muffler cover 20. Further, the airflow path is: when the vacuum pump works, the air is discharged from the pump chamber cover plate 40, flows from the first chamber 51 to the second chamber 52 through the vent hole 31 of the support plate 38, flows from the second chamber 52 to the third chamber 53 through the vent hole 231 of the elastic diaphragm 23, flows from the third chamber 53 to the fourth chamber 54 through the vent hole 14 between the noise reduction cover 10 and the buffer chamber 22, flows from the fourth chamber 54 to the fifth chamber 55 through the air release notch 151, and is discharged out of the vacuum pump through the vent hole of the motor flange by the fifth chamber 55. When the vacuum pump stops working, negative pressure is immediately generated between the supporting plate 38 and the pump chamber cover plate 40 (namely the first chamber 51), the elastic diaphragm 23 generates downward elastic deformation, and the elastic diaphragm 23 is tightly attached to the bead ribs 32, so that dirt can be prevented from entering the air outlet hole on the pump chamber cover plate 40.

In this embodiment, each part of the front silencing mechanism is designed to be disposed in a uniformly distributed or symmetrical position relationship as much as possible, so as to ensure the balance of the noise reduction performance at each position. The internal structures such as the pump chamber cover plate 40, the muffler cover 20, the path-extending check 30 (including the support plate 38), and the muffler cover 10 are all implemented as circular structures. Four air passing holes 231 of the elastic diaphragm 23 are uniformly distributed around the center; the vent holes 31 and the bead ribs 32 are arranged at the central position of the supporting plate 38, and the supporting blocks 35 are uniformly distributed around the center; the inner top surface of the silencing cover 10 is opposite to the center of the elastic diaphragm 23 and is used as a reference center, and the annular silencing grooves 11 are uniformly distributed around the reference center; the mounting convex ring 13, the pressing convex ring 15 and the annular silencing groove 11 are arranged in the position relation and the shape of concentric circles; the two abdicating concave surfaces 131 are centrosymmetric; the air relief notch 151 is uniform on the lower pressing convex ring 15.

The above examples are provided only for illustrating the present invention and are not intended to limit the present invention. Changes, modifications, etc. to the above-described embodiments are intended to fall within the scope of the claims of the present invention as long as they are in accordance with the technical spirit of the present invention.

Claims (11)

1. A low-noise electronic vacuum pump with a built-in one-way non-return structure is characterized in that a path extension non-return piece is arranged in the air inlet chamber, and a straight path between the pump chamber cover plate and the non-return hole forms an extended zigzag air path through the path extension non-return piece; when the vacuum pump works, the elastic diaphragm is forced to deform by the airflow, the bent air passage formed by the path extension check piece is communicated, and the airflow reaches the air passing hole through the bent air passage; when the vacuum pump stops working, the elastic diaphragm deforms due to the difference between the internal pressure and the external pressure of the elastic diaphragm, and the bent air path formed by the path extension check piece is blocked, so that the check is realized.

2. The low-noise electronic vacuum pump with the built-in one-way check structure as claimed in claim 1, wherein the path-extending check member comprises a support plate, the periphery of the support plate is in sealing fit with the inner side of the air inlet chamber of the noise reduction sleeve, the support plate and the air passing hole of the elastic diaphragm are provided with air holes in a staggered manner, and the bent air path is bent towards the air passing hole at the positions of the air holes.

3. The low-noise electronic vacuum pump with the built-in one-way check structure as claimed in claim 2, wherein a raised bead rib is arranged on one surface of the support plate facing the elastic diaphragm, and the bead rib surrounds the vent hole; when the elastic diaphragm is tightly attached to the bead convex rib, the bent gas path is blocked.

4. The low-noise electronic vacuum pump with a built-in one-way check structure as claimed in claim 3, wherein a raised supporting wall is disposed on a side of the supporting plate facing the elastic diaphragm, the supporting wall abuts against the elastic diaphragm, a clamping rib extends transversely from an outer wall of the supporting wall, and the clamping rib forms an interference fit with an inner wall of the air inlet chamber.

5. The low noise electronic vacuum pump of claim 2, wherein the support plate has a plurality of protruding support blocks on its side facing the pump chamber cover plate, and the support plate is kept spaced from the pump chamber cover plate by the support blocks.

6. The low-noise electronic vacuum pump with built-in one-way check structure as claimed in claim 5, wherein the support blocks of T-shaped structure are uniformly distributed around the vent holes in a radial manner, the straight sections of the support blocks of T-shaped structure face the vent holes, and the transverse sections of the support blocks face the edge of the support plate.

7. The low-noise electronic vacuum pump with a built-in one-way check structure as claimed in claim 2, wherein the elastic diaphragm forms a cambered surface towards the vent hole in a natural state.

8. The low-noise electronic vacuum pump with a built-in one-way check structure as claimed in claim 7, wherein the thickness of the elastic diaphragm is smaller than the thickness of the side wall of the air inlet chamber, and the thickness of the side wall of the air inlet chamber is smaller than the thickness of the inner wall of the buffer chamber.

9. The low-noise electronic vacuum pump with the built-in one-way check structure as claimed in claim 8, wherein the inner wall of the end part of the air inlet chamber facing the pump chamber cover plate is provided with a chamfer to form a bell mouth; the outer wall of the end part of the air chamber facing the pump chamber cover plate is provided with a chamfer.

10. The low-noise electronic vacuum pump with the built-in one-way check structure as claimed in claim 1, wherein at least one layer of annular silencing groove is arranged at the position of the inner top surface of the silencing cover opposite to the elastic diaphragm, and adjacent annular silencing grooves are communicated with each other through a plurality of air passing gaps; the annular silencing groove is formed by surrounding a plurality of layers of annular walls protruding towards the elastic diaphragm from the inner top surface of the silencing cover, and a plurality of air passing notches are formed in the annular walls; the buffer chamber is in interference fit with the mounting convex ring of the silencing cover and is connected in a sleeved manner; an air passing port is arranged between the buffer chamber and the mounting convex ring, and the air flow is extruded out of the silencing sleeve through the annular silencing groove and the air passing port.

11. The low-noise electronic vacuum pump with the built-in one-way check structure as claimed in claim 10, wherein the mounting convex ring is provided with a plurality of transversely concave receding concave surfaces, and gaps between the receding concave surfaces and the side wall of the buffer chamber form air passing ports; the outer wall of the silencing sleeve transversely extends to form a separating wing edge, a lower pressing convex ring is arranged at the position, opposite to the separating wing edge, of the inner top surface of the silencing cover, and the lower pressing convex ring abuts against the separating wing edge; the pressing convex ring is provided with an air leakage gap; after the airflow is extruded and flows out of the silencing sleeve, the airflow is extruded and flows out through the air leakage notch.

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