Low-noise vacuum booster

Abstract

The utility model discloses a low-noise vacuum booster which comprises a front housing, a rear housing, a diaphragm and an isolation seat, and the housing, the rear housing and the diaphragm are combined in a sealed mode to form a front cavity and a rear cavity which are separated by the diaphragm. The isolation seat is provided with a vacuum passage and an atmosphere passage which are communicated with the cavity, and a control assembly is assembled to adjust on-off. The vacuum passage is connected with the noise reduction interface, the inner diameter is increased, and an arc-shaped transition section is adopted to reduce airflow noise; the noise reduction sleeve A and the noise reduction sleeve B are assembled in the noise reduction connector and the atmosphere passage respectively, a flow guide layer, a sound absorption layer and an energy consumption layer are arranged in the noise reduction sleeve A and the noise reduction sleeve B, radial micropores are formed in the flow guide layer, honeycomb holes coaxial with the radial micropores are formed in the sound absorption layer, and broadband noise reduction is achieved through vortex flow division, sound wave absorption and energy consumption. The structure effectively inhibits airflow and mechanical noise while ensuring quick response of braking, and remarkably improves driving quietness.

Description

Technical Field

[0001] This utility model relates to the field of vacuum booster technology, specifically a low-noise vacuum booster. Background Technology

[0002] As a key component of the automotive braking system, the vacuum booster utilizes the vacuum generated by the engine intake manifold or vacuum pump to create a pressure difference between the front and rear chambers during braking, providing auxiliary braking force to the driver, thereby reducing the effort required to operate the brake pedal and improving driving comfort. However, traditional vacuum boosters have significant noise problems during operation, mainly stemming from the following aspects:

[0003] 1. Gas flow noise: When the vacuum booster is braking or resetting, the high-speed gas flow in the vacuum passage and atmospheric passage easily generates turbulence and eddies, which in turn causes a high-frequency whistling sound. Especially under emergency braking or frequent braking conditions, the airflow noise is more obvious, affecting the quietness of the vehicle interior.

[0004] 2. Mechanical vibration noise: When rubber valves and control plungers open and close the vacuum passage and atmospheric passage, mechanical impact noise may be generated due to instantaneous air pressure changes or component collisions. In addition, the reciprocating motion of the diaphragm and the isolator may also transmit vibration noise to the vehicle body structure.

[0005] 3. Insufficient noise reduction design: Existing vacuum boosters usually reduce noise only through simple sound-absorbing structures such as single-layer filters or buffer pads. However, such designs have limited absorption effect on broadband noise, especially low-frequency noise, and may sacrifice response speed.

[0006] Therefore, there is an urgent need for a new type of low-noise vacuum booster that can suppress noise generation at the source and efficiently absorb broadband noise by optimizing the airflow path and multi-layer composite noise reduction structure while ensuring rapid response, thereby improving driving comfort. Utility Model Content

[0007] In view of the above-mentioned shortcomings in the existing technology, the purpose of this utility model is to provide a noise vacuum booster that, while ensuring efficient braking assistance, significantly reduces operating noise, improves driving comfort and product reliability, and has significant market application value.

[0008] The technical solution adopted by this utility model to achieve the above-mentioned objective is: a low-noise vacuum booster, including a front cover, a rear cover, a diaphragm, and an isolation seat that are kept in a matching assembly. The front cover and the rear cover are sealed together to form an operating cavity. The outer edge of the diaphragm is sealed together with the front cover and the rear cover and divides the operating cavity into a front chamber and a rear chamber. The isolation seat is fixedly assembled with the diaphragm.

[0009] It also includes a master cylinder push rod and a control assembly. The rear end of the isolation seat has an assembly cavity. The isolation seat has a vacuum passage and an atmospheric passage. The vacuum passage is used to connect the front chamber and the assembly cavity, and the atmospheric passage is used to connect the rear chamber and the assembly cavity. The master cylinder push rod is assembled into the front cover and connected to the isolation seat. The control assembly is assembled in the assembly cavity and is used to control the opening and closing of the vacuum passage and the atmospheric passage.

[0010] The front side of the isolation seat is fixed with a noise reduction interface that is in communication with the vacuum passage. The inner diameter of the noise reduction interface is larger than the inner diameter of the vacuum passage. The connection between the noise reduction interface and the vacuum passage is set as an arc-shaped transition section. A noise reduction sleeve A is installed at the noise reduction interface, and a noise reduction sleeve B is installed in the atmospheric passage.

[0011] The noise reduction sleeves A and B are each equipped with a flow guiding layer, a sound absorbing layer, and an energy dissipation layer arranged sequentially from the inside to the outside. The flow guiding layer has radially arranged micropores, and the sound absorbing layer has honeycomb holes that are coaxially distributed with the radially arranged micropores.

[0012] Based on the above technical solutions, in order to ensure that the control components can accurately control the opening and closing states of the vacuum passage and the atmospheric passage, so as to adjust the rear chamber between the vacuum state and the standard gas pressure, the following technical solutions are provided.

[0013] The control assembly includes a control plunger, a control push rod, and a rubber valve. The control plunger is assembled into the assembly cavity and grounded to the inner end of the rubber valve. The control push rod is arranged inside the rubber valve and is ball-jointed to the control plunger. The rubber valve is arranged in the assembly cavity and linked with the control push rod.

[0014] Based on the above technical solutions, in order to ensure that the noise reduction sleeve A can be stably assembled at the noise reduction interface, and at the same time facilitate the disassembly and maintenance of the noise reduction sleeve A and the flow guiding layer, sound absorption layer and energy dissipation layer assembled therein, the following technical solutions are provided.

[0015] A limiting ring A is fixed to the outer wall of the noise reduction interface, and a positioning ring A is fixed to the end of the noise reduction sleeve A. The noise reduction sleeve A is screwed to the outer wall of the noise reduction interface, and the limiting ring A and the positioning ring A are kept in a sealed fit.

[0016] Based on the above technical solutions, in order to ensure that the noise reduction sleeve B can be stably assembled in the atmospheric passage, and at the same time facilitate the disassembly and maintenance of the noise reduction sleeve B and the air guiding layer, sound absorbing layer and energy dissipation layer assembled therein, the following technical solutions are provided.

[0017] An inner limiting ring B is fixedly connected to the inner end of the atmospheric passage, and an outer limiting ring B is fixedly connected to the outer end of the atmospheric passage. An inner positioning ring B and an outer positioning ring B are fixedly connected to both ends of the noise reduction sleeve B, respectively. The noise reduction sleeve B is screwed into the atmospheric passage. The inner positioning ring B and the inner limiting ring B are kept in a sealed fit, and the outer positioning ring B and the outer limiting ring B are kept in contact.

[0018] Based on the above technical solutions, in order to ensure that the flow guiding layer, sound absorbing layer and energy dissipation layer involved can be stably installed in noise reduction sleeve A and noise reduction sleeve B, the following technical solutions are provided.

[0019] The noise reduction sleeve A has an assembly ring groove A, and the noise reduction sleeve B has an assembly ring groove B. The flow guiding layer, sound absorbing layer, and energy dissipation layer are nested in both the assembly ring groove A and the assembly ring groove B.

[0020] Based on the above technical solution, in order to ensure the circumferential vacuum of the rear chamber and the speed of atmospheric filling, and to improve the response speed of the vacuum booster while keeping the noise level low, multiple sets of vacuum passages and atmospheric passages are arranged in a ring array.

[0021] The beneficial effects of this utility model are:

[0022] 1. Significantly reduces airflow noise and improves driving quietness. Noise-reducing sleeves A and B are installed in the vacuum passage and atmospheric passage respectively. The internal structure of the sleeves adopts a three-layer composite structure of a flow guide layer, a sound absorption layer and an energy dissipation layer, which can effectively divide eddies and absorb high-frequency noise. The honeycomb structure enhances sound wave reflection and energy dissipation, significantly reducing the howling noise generated by airflow. The noise reduction interface adopts an arc-shaped transition section and increases the inner diameter to reduce the airflow velocity and reduce the generation of turbulent noise.

[0023] 2. To enhance sealing performance and reduce mechanical vibration and noise, a sealing ring A is installed between the front cover and the master cylinder push rod to ensure the sealing of the front chamber during the movement of the master cylinder push rod, preventing abnormal noise caused by air leakage. A sealing ring B is installed between the rear cover and the isolator to ensure the sealing stability of the isolator as it moves with the diaphragm, reducing vibration and noise caused by air pressure fluctuations. The control assembly uses a precise fit between rubber valves and control plungers to smoothly switch between vacuum and atmospheric passages during braking, reducing impact noise during valve opening and closing.

[0024] 3. Optimized disassembly and maintenance, and improved service life: Noise-reducing sleeve A and noise-reducing sleeve B both adopt a screw-on design. The cooperation of the limit ring and the positioning ring enables the quick disassembly and assembly of noise-reducing sleeve A and noise-reducing sleeve B, which facilitates the replacement or maintenance of noise-reducing components.

[0025] 4. Improve braking response speed while balancing noise reduction and performance. The circular array of vacuum and atmospheric passages ensures rapid airflow while reducing noise, allowing the rear chamber to quickly switch between vacuum and atmospheric states, thus improving the response speed of braking assistance. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0027] Figure 2 A schematic diagram of the isolation seat and the components assembled on it;

[0028] Figure 3 This is a structural diagram of the noise reduction sleeve A and its assembled components in a disassembled state.

[0029] Figure 4 This is a structural diagram of the noise reduction sleeve B and its assembled components in a disassembled state.

[0030] Figure 5 This is a structural diagram showing the disassembled state of the flow guiding layer, sound absorbing layer, and energy dissipation layer.

[0031] In the diagram: 1 Front cover, 11 Exhaust port, 12 Sealing ring A, 2 Rear cover, 21 Sealing ring B, 22 Dustproof sleeve, 3 Diaphragm, 4 Isolation seat, 41 Assembly cavity, 411 Felt filter ring, 412 Reaction disc, 42 Vacuum passage, 421 Noise reduction interface, 422 Arc transition section, 423 Limiting ring A, 424 Sealing ring A, 43 Atmospheric passage, 431 Inner limiting ring B, 432 Outer limiting ring B, 433 Sealing ring B, 5 Master cylinder push rod, 6 Control assembly, 61 Control plunger, 62 Control push rod, 63 Rubber valve, 71 Noise reduction sleeve A, 711 Positioning ring A, 712 Assembly ring groove A, 72 Noise reduction sleeve B, 721 Inner positioning ring B, 722 Outer positioning ring B, 723 Assembly ring groove B, 73 Guide layer, 731 Radial micropores, 74 Sound absorption layer, 741 Honeycomb holes, 75 Energy dissipation layer. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0033] Please see Figure 1-5 A low-noise vacuum booster includes a front cover 1, a rear cover 2, a diaphragm 3, and an isolation seat 4 that are kept in a matching assembly. The front cover 1 and the rear cover 2 are sealed together to form an operating cavity. The outer edge of the diaphragm 3 is sealed together with the front cover 1 and the rear cover 2 and divides the operating cavity into a front chamber and a rear chamber. The isolation seat 4 is fixedly assembled with the diaphragm 3.

[0034] It also includes a master cylinder push rod 5 and a control component 6. An assembly cavity 41 is provided at the rear end of the isolation seat 4. A vacuum passage 42 and an atmospheric passage 43 are provided in the isolation seat 4. The vacuum passage 42 is used to connect the front chamber and the assembly cavity 41, and the atmospheric passage 43 is used to connect the rear chamber and the assembly cavity 41. The master cylinder push rod 5 is assembled into the front cover 1 and connected to the isolation seat 4. The control component 6 is assembled in the assembly cavity 41 and is used to control the on / off state of the vacuum passage 42 and the atmospheric passage 43.

[0035] The outer edges of the front cover 1, diaphragm 3, and rear cover 2 can be sealed together by nesting and pressing to achieve a fixed combination of the three. An exhaust port 11 is provided on the front cover 1, and a one-way valve is installed on the exhaust port 11. The one-way valve is connected to a vacuum pump or the intake pipe behind the throttle valve to evacuate the front chamber.

[0036] A sealing ring A12 is installed at the connection between the front cover 1 and the main cylinder push rod 5, which can ensure the sealing performance of the front chamber when the main cylinder push rod 5 moves in extension and retraction. A sealing ring B21 is installed between the rear cover 2 and the isolation seat 4, which can ensure the sealing performance of the two when the isolation seat 4 moves with the diaphragm 3.

[0037] The port of the assembly cavity 41 extends to the outside of the rear cover 2. A felt filter ring 411 is installed at the port position. When outside air enters the assembly cavity 41 through the felt filter ring 411, it can filter dust and impurities to ensure the cleanliness of the vacuum booster.

[0038] An assembly groove is provided at the front end of the isolation seat 4. A sliding groove communicating with the assembly cavity 41 is provided at the axis of the assembly groove. A rubber reaction disc 412 is nested in the assembly groove, and the rear end of the main cylinder push rod 5 is arranged in the assembly groove and abuts against the rubber reaction disc 412. A dustproof rubber sleeve 22 is installed between the end of the assembly cavity 41 and the rear cover 2 to prevent external dust from entering the inside of the vacuum booster.

[0039] The front side of the isolation seat 4 is fixed with a noise reduction interface 421 that is in communication with the vacuum passage 42. The inner diameter of the noise reduction interface 421 is larger than the inner diameter of the vacuum passage 42. The connection between the noise reduction interface 421 and the vacuum passage 42 is set as an arc-shaped transition section 422. A noise reduction sleeve A71 is installed at the noise reduction interface 421, and a noise reduction sleeve B72 is installed in the atmospheric passage 43.

[0040] Both noise reduction sleeves A71 and B72 are equipped with a flow guiding layer 73, a sound absorbing layer 74, and an energy dissipation layer 75 arranged sequentially from the inside to the outside. The flow guiding layer 73 has radially arranged micropores 731, and the sound absorbing layer 74 has honeycomb holes 741 that are coaxially distributed with the radially arranged micropores 731.

[0041] The inner diameter of the noise reduction interface 421 is increased and connected to the vacuum passage 42 through the arc transition section 422, so that the gas flow rate at this point is reduced during the vacuuming process, thereby reducing turbulence and the generation of accompanying noise.

[0042] During operation, the vacuum booster generates whistling noise due to gas flow in the vacuum passage 42 and atmospheric passage 43. The noise is reduced and absorbed by the noise reduction sleeves A71 and B72, as well as the flow guide layer 73, sound absorption layer 74, and energy dissipation layer 75, thereby significantly reducing the noise during operation and preventing the noise from affecting driving comfort.

[0043] Specifically, the flow guide layer 73 is made of stainless steel with a smooth surface, which can reduce collision noise during airflow. In conjunction with the radial micropores 731, it can divide eddies, reduce turbulence regeneration, and absorb mid-to-high frequency noise.

[0044] The sound-absorbing layer 74 is made of aluminum alloy. Its honeycomb holes 741 are hexagonal in design and twisted along the axial direction, which allows noise entering it to be fully reflected and transmitted. Together with the energy-dissipating layer 75 formed by high-temperature glass wool, it can fully absorb and dissipate noise and broaden the absorption of low-frequency noise.

[0045] To ensure that the control component 6 can accurately control the on / off state of the vacuum passage 42 and the atmospheric passage 43, so as to adjust the rear chamber between the vacuum state and the standard gas pressure, the following technical solution is provided.

[0046] The control assembly 6 includes a control plunger 61, a control push rod 62, and a rubber valve 63. The control plunger 61 is assembled into the assembly cavity 41 and is grounded to the inner end of the rubber valve 63. The control push rod 62 is arranged inside the rubber valve 63 and is ball-jointed to the control plunger 61. The rubber valve 63 is arranged in the assembly cavity 41 and is linked with the control push rod 62.

[0047] When the brake pedal is depressed, the control push rod 62 is pushed to move forward to the front cover 1, thereby driving the inner end of the rubber valve 63 and the control plunger 61 to move, so as to close the vacuum passage 42, and at the same time separate the control plunger 61 from the inner end of the rubber valve 63 and open the atmospheric passage 43. At this time, the outside air can enter the rear chamber through the gap between the rubber valve 63 and the control plunger 61 and the atmospheric passage 43. The pressure difference between the front chamber and the rear chamber can push the separation diaphragm 3 and the isolating seat 4 to move forward to the front cover 1, thereby pushing the master cylinder push rod 5 to generate braking force to act on the hydraulic system of the brake.

[0048] When the brake pedal is released, the spring can push the isolating seat 4 to move backward and reset, and under the action of the rubber reaction disc 412, it can push the control component 6 to reset. At this time, the vacuum passage 42 and the atmospheric passage 43 remain connected and isolated from the atmospheric environment. At this time, the rear chamber and the front chamber are connected and are also in a vacuum state. Since the pressure difference on both sides disappears, the spring installed in the front cover 1 can squeeze the isolating seat 4 and the diaphragm 3 towards the rear cover 2 side to achieve the purpose of resetting.

[0049] To ensure that the noise reduction sleeve A71 can be stably assembled at the noise reduction interface 421, and to facilitate the disassembly and maintenance of the noise reduction sleeve A71 and the flow guiding layer 73, sound absorbing layer 74 and energy dissipation layer 75 assembled therein, the following technical solution is provided.

[0050] A limiting ring A423 is fixedly connected to the outer wall of the noise reduction interface 421, and a positioning ring A711 is fixedly connected to the end of the noise reduction sleeve A71. The noise reduction sleeve A71 is screwed to the outer wall of the noise reduction interface 421, and the limiting ring A423 and the positioning ring A711 are kept in a sealed fit.

[0051] A sealing ring A424 is provided between the limiting ring A423 and the positioning ring A711 to ensure the sealing effect of the connection between the two. Through the cooperation of the limiting ring A423 and the positioning ring A711, the noise reduction sleeve A71 can be stably assembled at the noise reduction interface 421 in a detachable manner.

[0052] To ensure that the noise reduction sleeve B72 can be stably assembled in the atmospheric passage 43, and to facilitate the disassembly and maintenance of the noise reduction sleeve B72 and the airflow guiding layer 73, sound absorbing layer 74 and energy dissipation layer 75 assembled therein, the following technical solution is provided.

[0053] An inner limiting ring B431 is fixedly connected to the inner end of the atmospheric passage 43, and an outer limiting ring B432 is fixedly connected to the outer end of the atmospheric passage 43. An inner positioning ring B721 and an outer positioning ring B722 are fixedly connected to both ends of the noise reduction sleeve B72, respectively. The noise reduction sleeve B72 is screwed into the atmospheric passage 43. The inner positioning ring B721 and the inner limiting ring B431 are sealed and fitted together, and the outer positioning ring B722 and the outer limiting ring B432 are in contact.

[0054] A sealing ring B433 is provided between the inner limiting ring B431 and the inner positioning ring B721 to ensure the sealing effect of the noise reduction sleeve B72 and the atmospheric passage 43. The inner positioning ring B721 cooperates with the inner limiting ring B431, and the outer positioning ring B722 cooperates with the outer positioning ring B722, which can realize the stability of the noise reduction sleeve B72 in the atmospheric passage 43.

[0055] To ensure that the flow guiding layer 73, sound absorbing layer 74, and energy dissipation layer 75 can be stably installed in the noise reduction sleeve A71 and noise reduction sleeve B72, the following technical solution is provided.

[0056] The noise reduction sleeve A71 has an assembly ring groove A712, and the noise reduction sleeve B72 has an assembly ring groove B723. The assembly ring groove A712 and the assembly ring groove B723 are both nested with a flow guiding layer 73, a sound absorbing layer 74, and an energy dissipation layer 75.

[0057] The assembly ring grooves A712 and B723 ensure that the flow guiding layer 73, sound absorbing layer 74, and energy dissipation layer 75 are stably assembled in the noise reduction sleeves A71 and B72 according to the arrangement order, and perform the function of sound absorption and noise reduction.

[0058] To ensure the circumferential vacuum of the rear chamber and the speed of atmospheric filling, and to improve the response speed of the vacuum booster while keeping noise levels low, multiple sets of vacuum passages 42 and atmospheric passages 43 are arranged in a ring array. By using multiple sets of vacuum passages 42 and atmospheric passages 43 as airflow paths, the airflow rate can be significantly improved. Noise-reducing sleeves A71 and B72 are installed at corresponding positions in each vacuum passage 42 and atmospheric passage 43, which can significantly improve the response speed of the vacuum booster while limiting noise generation.

[0059] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0060] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-noise vacuum booster, comprising a front housing (1), a rear housing (2), a diaphragm (3), and an isolation seat (4) that are in a matching assembly, wherein the front housing (1) and the rear housing (2) are sealed together to form an operating cavity, the outer edge of the diaphragm (3) is sealed together with the front housing (1) and the rear housing (2) and divides the operating cavity into a front chamber and a rear chamber, and the isolation seat (4) is fixedly assembled with the diaphragm (3); It also includes a master cylinder push rod (5) and a control component (6). The rear end of the isolation seat (4) is provided with an assembly cavity (41). The isolation seat (4) is provided with a vacuum passage (42) and an atmospheric passage (43). The vacuum passage (42) is used to connect the front chamber and the assembly cavity (41). The atmospheric passage (43) is used to connect the rear chamber and the assembly cavity (41). The master cylinder push rod (5) is assembled into the front cover (1) and connected to the isolation seat (4). The control component (6) is assembled in the assembly cavity (41) and is used to control the opening and closing attitude of the vacuum passage (42) and the atmospheric passage (43). Its features are: The front side of the isolation seat (4) is fixed with a noise reduction interface (421) that is in communication with the vacuum passage (42). The inner diameter of the noise reduction interface (421) is larger than the inner diameter of the vacuum passage (42). The connection between the noise reduction interface (421) and the vacuum passage (42) is set as an arc transition section (422). A noise reduction sleeve A (71) is installed at the noise reduction interface (421). A noise reduction sleeve B (72) is installed in the atmospheric passage (43). The noise reduction sleeve A (71) and noise reduction sleeve B (72) are each equipped with a flow guiding layer (73), a sound absorbing layer (74), and an energy dissipation layer (75) arranged sequentially from the inside to the outside. The flow guiding layer (73) has radially arranged micropores (731) evenly distributed, and the sound absorbing layer (74) has honeycomb pores (741) evenly distributed coaxially with the radially arranged micropores (731).

2. The low-noise vacuum booster according to claim 1, characterized in that: The control assembly (6) includes a control plunger (61), a control push rod (62), and a rubber valve (63). The control plunger (61) is assembled into the assembly cavity (41) and grounded to the inner end of the rubber valve (63). The control push rod (62) is arranged inside the rubber valve (63) and is ball-jointed to the control plunger (61). The rubber valve (63) is arranged in the assembly cavity (41) and linked with the control push rod (62).

3. The low-noise vacuum booster according to claim 1, characterized in that: A limiting ring A (423) is fixed to the outer wall of the noise reduction interface (421), and a positioning ring A (711) is fixed to the end of the noise reduction sleeve A (71). The noise reduction sleeve A (71) is screwed to the outer wall of the noise reduction interface (421), and the limiting ring A (423) and the positioning ring A (711) are sealed and fitted together.

4. A low-noise vacuum booster according to claim 1, characterized in that: An inner limiting ring B (431) is fixedly connected to the inner end of the atmospheric passage (43), and an outer limiting ring B (432) is fixedly connected to the outer end of the atmospheric passage (43). An inner positioning ring B (721) and an outer positioning ring B (722) are fixedly connected to both ends of the noise reduction sleeve B (72). The noise reduction sleeve B (72) is screwed into the atmospheric passage (43). The inner positioning ring B (721) and the inner limiting ring B (431) are sealed and fitted together. The outer positioning ring B (722) and the outer limiting ring B (432) are in contact.

5. A low-noise vacuum booster according to claim 1, characterized in that: The noise reduction sleeve A (71) has an assembly ring groove A (712), and the noise reduction sleeve B (72) has an assembly ring groove B (723). The flow guiding layer (73), the sound absorbing layer (74), and the energy dissipation layer (75) are nested in both the assembly ring groove A (712) and the assembly ring groove B (723).

6. A low-noise vacuum booster according to claim 1, characterized in that: Both the vacuum passage (42) and the atmospheric passage (43) are provided with multiple sets arranged in a ring array.

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