A device for testing the permeability of brake disc casting sand

Abstract

This utility model relates to the field of air permeability testing technology for brake disc casting sand molds, and discloses a brake disc casting sand air permeability testing device, including a base, a testing cavity opened on the top of the base, a top frame supported by a cylinder and fixedly installed on the top of the base, a cylinder fixedly installed on the top of the top frame, and a differential pressure type air tightness tester fixedly installed on the output end of the cylinder. The testing cavity is equipped with a sealing module. During the air tightness testing process, as the air pressure inside the brake disc casting sand mold continuously increases, the pressure cylinder moves downward, squeezing and pushing the rubber ring from the inside out, causing it to tightly fit against the gap between the bottom port of the brake disc casting sand mold and the sealing disc. Combined with the deformation of the corrugated groove itself under pressure, this provides a secondary sealing and isolation effect for possible leakage between the bottom port of the brake disc casting sand mold and the sealing disc.

Description

Technical Field

[0001] This utility model relates to the field of air permeability testing technology for brake disc casting sand molds, specifically a device for testing the air permeability of brake disc casting sand. Background Technology

[0002] The airtightness inspection of brake disc casting sand mold is a key step to ensure product quality. In the existing technology, the pressure decay method is mainly used to detect minute leaks. In the testing process, the differential pressure method is commonly used. First, the mold cavity is sealed, and then a differential pressure airtightness tester is used to inflate it to the set pressure. After that, the pressure drop or leakage rate is monitored to obtain the airtightness test data of the casting sand mold.

[0003] However, in actual use, the aforementioned equipment requires sealing the open surface of the brake disc casting mold. Then, the inflation end of the differential pressure airtightness tester is aligned and pressed tightly against the port of the brake disc casting sand mold. Afterward, air is injected into the mold using the differential pressure airtightness tester. When sealing the open surface of the mold, a certain gap still exists between the groove on the open surface and the sealing plate. During the testing process, this gap tends to widen further as the air pressure inside the mold cavity increases, creating more gaps and potentially causing slight leaks, thus affecting the accuracy of the air permeability test. Therefore, we propose a brake disc casting sand air permeability testing device. Utility Model Content

[0004] The purpose of this invention is to provide a device for testing the permeability of brake disc casting sand, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a brake disc casting sand permeability testing device, comprising a base, a testing chamber opened on the top of the base, a top frame supported by a cylinder and fixedly installed on the top of the base, a cylinder fixedly installed on the top of the top frame, and a differential pressure type air tightness tester fixedly installed on the output end of the cylinder. The testing chamber is provided with a sealing module, the sealing module including a sealing plate fixedly installed on the bottom inner wall of the testing chamber, a guide rod fixedly installed on the bottom inner wall of the testing chamber, a pressure cylinder slidably connected to the top of the guide rod, a spring fixedly connected between the pressure cylinder and the bottom inner wall of the testing chamber, a flexible shielding curtain provided on the outer wall of the pressure cylinder, and six sets of arc-shaped push plates hinged to the side wall of the pressure cylinder by six sets of pressure rods. Rubber rings are sleeved on the outer surface of the six sets of arc-shaped push plates, and the outer wall of the rubber rings is provided with a wave groove.

[0006] Preferably, the bottom center inner wall of the detection cavity is provided with a circular hole with a diameter that matches the outer diameter of the pressure cylinder, and the pressure cylinder slides in conjunction with the circular hole.

[0007] Preferably, the sealing disc has a through hole with a diameter larger than the outer diameter of the pressure cylinder at its axial center, and a flexible shielding curtain is placed on top of the through hole and completely covers it, with the inner surface of the top of the through hole having rounded corners.

[0008] Preferably, the guide rod is square in shape, and a square hole with a length greater than that of the guide rod is opened at the center of the bottom of the pressure cylinder, and the guide rod slides in conjunction with the square hole.

[0009] Preferably, the wave groove is arranged in a circular shape on the side of the rubber ring away from the arc-shaped push plate, and the wave groove is evenly distributed on the upper and lower sides of the horizontal central axis of the rubber ring.

[0010] Preferably, the rubber ring has a hollow cavity inside, and the inner surface of the hollow cavity is fixedly installed with a number of reinforcing ribs in a circumferential array.

[0011] Preferably, the hollow cavity cross-section is configured as a gourd shape including a wide diameter end and a narrow diameter end, and the narrow diameter end of the hollow cavity is located on the side close to the arc-shaped push plate.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: During the airtightness test, as the air pressure inside the casting sand mold of the brake disc continuously increases, the arc-shaped push plate is pushed outward by the transmission of the pressure cylinder and the pressure rod, causing the rubber ring to undergo extrusion deformation from the inside out. This causes it to fit tightly against the gap between the bottom port of the casting sand mold of the brake disc and the sealing plate. Combined with the deformation caused by the pressure of the corrugated groove itself, an isolation cavity is formed between the rubber ring and the inner surface of the bottom port of the casting sand mold of the brake disc. This provides a secondary sealing and isolation effect for possible leakage between the bottom port of the casting sand mold of the brake disc and the sealing plate. The gourd-shaped hollow cavity makes it easier for one side of the outer surface of the rubber ring to deform and gradually cover and fit along the inner surface of the bottom port of the casting sand mold of the brake disc from bottom to top, increasing the sealing area at the bottom port of the casting sand mold of the brake disc, ensuring the airtightness at the bottom port of the casting sand mold of the brake disc, and thus ensuring the accuracy of the test data. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Figure 2 This is a cross-sectional view of the base structure of this utility model;

[0015] Figure 3 This is a schematic cross-sectional view of the sealing disc of this utility model;

[0016] Figure 4 This is a bottom view of a partially exploded pressure cylinder of this utility model;

[0017] Figure 5 This is a partial view of the closed module of this utility model;

[0018] Figure 6 This is a cross-sectional view of the rubber ring of this utility model.

[0019] The components represented by each number in the attached diagram are listed below: 1. Base; 2. Detection chamber; 3. Top frame; 4. Cylinder; 5. Differential pressure type airtightness tester; 6. Hollow cavity; 7. Sealing plate; 8. Guide rod; 9. Pressure cylinder; 10. Spring; 11. Flexible shielding curtain; 12. Pressure rod; 13. Arc-shaped push plate; 14. Rubber ring; 15. Corrugated groove; 16. Reinforcing rib. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figures 1-6 The device for testing the permeability of brake disc casting sand shown in the figure includes a base 1, a test chamber 2 opened on the top of the base 1, a top frame 3 supported by a cylinder and fixedly installed on the top of the base 1, a cylinder 4 fixedly installed on the top of the top frame 3, and a differential pressure type air tightness tester 5 fixedly installed on the output end of the cylinder 4.

[0022] During testing, the casting sand mold of the brake disc is first placed in the testing chamber 2 and fixed with a positioning pin. Then, the cylinder 4 is activated, which drives the differential pressure air tightness tester 5 downward in the vertical direction until the bottom inflation part of the differential pressure air tightness tester 5 aligns with and compacts the port of the casting sand mold of the brake disc. At this point, the cylinder 4 is closed to maintain the position of the differential pressure air tightness tester 5 in the vertical direction. The differential pressure air tightness tester 5 is then activated to inflate the inner cavity of the casting sand mold of the brake disc. After reaching the preset air pressure, the inflation is stopped. After a certain period of time, the air tightness of the casting sand mold of the brake disc is judged by the air pressure difference monitored by the differential pressure air tightness tester 5.

[0023] The detection chamber 2 is equipped with a sealing module, which includes a sealing plate 7 fixedly installed on the bottom inner wall of the detection chamber 2. A guide rod 8 is fixedly installed on the bottom inner wall of the detection chamber 2. The top of the guide rod 8 is slidably connected to a pressure cylinder 9. A spring 10 is fixedly connected between the pressure cylinder 9 and the bottom inner wall of the detection chamber 2. A flexible shielding curtain 11 is provided on the outer wall of the pressure cylinder 9. Six sets of arc-shaped push plates 13 are hinged to the side wall of the pressure cylinder 9 through six sets of pressure rods 12. A rubber ring 14 is sleeved on the outer surface of the six sets of arc-shaped push plates 13. A wave groove 15 is opened on the outer wall of the rubber ring 14.

[0024] Please see Figures 3-5 The size of the sealing disc 7 is adapted to the detection cavity 2, thereby filling the bottom space of the entire detection cavity 2 and preventing the casting sand mold of the brake disc from shifting within the detection cavity 2, which would affect the accuracy of the test results. At the same time, the guide rod 8, the pressure cylinder 9, and the differential pressure airtightness tester 5 are all set on the same vertical line to ensure the stability of the test process. In the initial state, the rubber ring 14 is located inside the bottom port of the casting sand mold of the brake disc, which facilitates the rubber ring 14 to seal the gap between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, preventing leakage when the air pressure in the mold cavity is too high, which would affect the accuracy of the test data.

[0025] The bottom center inner wall of the detection chamber 2 has a circular hole with a diameter that matches the outer diameter of the pressure cylinder 9, and the pressure cylinder 9 slides in the circular hole.

[0026] Because the bottom of the pressure cylinder 9 has a motion redundancy, after the air pressure inside the casting sand mold of the brake disc increases, the pressure cylinder 9 will move downward along the circular hole, and drive the top of the pressure rod 12 hinged to the outside of the pressure cylinder 9 to move downward. At this time, the inclined pressure rod 12 will push the arc-shaped push plate 13 away from the pressure cylinder 9, thereby squeezing and pushing the rubber ring 14 from the inside out, so that it fits tightly against the gap between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, ensuring that the gap will not leak under high air pressure.

[0027] The sealing disc 7 has a through hole with a diameter larger than the outer diameter of the pressure cylinder 9 at its axis, and a flexible shielding curtain 11 is placed on top of the through hole and completely covers it. The inner surface of the top of the through hole is rounded.

[0028] The vertical displacement of the pressure cylinder 9 will not interfere with the movement of the sealing plate 7. Furthermore, the flexible shielding curtain 11 is made of tear-resistant rubber, which can ensure that one side can move up and down with the pressure cylinder 9, while also preventing air leakage at the gap between the pressure cylinder 9 and the through hole, thus affecting the airtightness of the entire testing equipment during the testing process.

[0029] The guide rod 8 is square in shape, and a square hole with a length greater than that of the guide rod 8 is opened at the center of the bottom of the pressure cylinder 9. The guide rod 8 slides in conjunction with the square hole.

[0030] Please see Figures 3-4 The cooperation between the guide rod 8 and the square hole can restrict the pressure cylinder 9 to move only in the vertical direction, and prevent the possible rotation of the pressure cylinder 9 from causing the arc-shaped push plate 13 to rotate, which would affect the effect of the rubber ring 14 on sealing the gap between the bottom port of the casting sand mold of the brake disc and the sealing disc 7.

[0031] The wave groove 15 is arranged in a circular shape on the side of the rubber ring 14 away from the arc-shaped push plate 13, and the wave groove 15 is evenly distributed on the upper and lower sides of the horizontal central axis of the rubber ring 14.

[0032] When the rubber ring 14 is subjected to outward thrust, the corrugated groove 15 directly contacts the inner surface of the bottom port of the casting sand mold of the brake disc. As the thrust on the rubber ring 14 increases, the corrugated groove 15 itself will also undergo a certain deformation, thereby forming an isolation cavity between the rubber ring 14 and the inner surface of the bottom port of the casting sand mold of the brake disc. Even if a small gap appears between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, the isolation cavity formed by the corrugated groove 15 will have a secondary sealing effect, reducing the possibility of leakage between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, and ensuring the accuracy of the airtightness test results.

[0033] The rubber ring 14 has a hollow cavity 6 inside, and a number of reinforcing ribs 16 are fixedly installed in a circumferential array on the inner surface of the hollow cavity 6.

[0034] Please see Figure 6 The reinforcing ribs 16 can maintain the shape of the hollow cavity 6, and after the arc-shaped push plate 13 resets and no longer squeezes the rubber ring 14, the hollow cavity 6 can be reset so that the rubber ring 14 can be reused continuously.

[0035] The cross-section of the hollow cavity 6 is configured as a gourd shape including a wide diameter end and a narrow diameter end, and the narrow diameter end of the hollow cavity 6 is located on the side close to the arc-shaped push plate 13.

[0036] When the rubber ring 14 is compressed, the side closer to the arc-shaped push plate 13 is thicker. When the arc-shaped push plate 13 compresses, the space at the narrow diameter end is compressed, and the pressure is transmitted to the wide diameter end. This causes the outer rubber wall of the rubber ring 14 to expand and deform more easily and gradually cover and adhere to the inner surface of the bottom port of the casting sand mold of the brake disc from bottom to top. This increases the sealing area at the bottom port of the casting sand mold of the brake disc, ensures the airtightness at the bottom port of the casting sand mold of the brake disc, and thus ensures the accuracy of the test data.

[0037] Working principle: First, the casting sand mold of the brake disc to be tested is placed in the testing chamber 2 and fixed by the positioning pin. At this time, the rubber ring 14 is located in the gap between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, which works with the sealing disc 7 to ensure the seal at the bottom port of the casting sand mold of the brake disc. Then, the cylinder 4 is activated, driving the differential pressure airtightness tester 5 to move downwards until the bottom inflation part of the differential pressure airtightness tester 5 aligns with and compacts the casting sand mold port of the brake disc. At this time, the cylinder 4 is closed, and the differential pressure airtightness tester 5 maintains its current height. Start the differential pressure air tightness tester 5 and inflate the inner cavity of the casting sand mold of the brake disc. When the air pressure in the inner cavity of the mold rises to a level greater than atmospheric pressure, the air pressure in the inner cavity of the mold will exert downward pressure on the pressure cylinder 9 and the flexible shielding curtain 11 on its outer side, causing the pressure cylinder 9 to move downward. During this process, the pressure rod 12 pushes the arc-shaped push plate 13 outward, thereby squeezing and pushing the rubber ring 14 from the inside out, causing it to fit tightly against the gap between the bottom port of the casting sand mold of the brake disc and the sealing disc 7, thus achieving a seal at the bottom port of the casting sand mold of the brake disc.

[0038] As the differential pressure air tightness tester 5 continues to inflate, the air pressure in the mold cavity reaches the preset air pressure and then the inflation stops. After a certain period of time, the air tightness of the casting sand mold of the brake disc is judged by the air pressure difference monitored by the differential pressure air tightness tester 5.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for testing the permeability of casting sand for brake discs, comprising a base (1), a testing chamber (2) opened on the top of the base (1), a top frame (3) supported by a cylinder and fixedly installed on the top of the base (1), a cylinder (4) fixedly installed on the top of the top frame (3), and a differential pressure type air tightness tester (5) fixedly installed at the output end of the cylinder (4), characterized in that: The detection chamber (2) is equipped with a sealing module. The sealing module includes a sealing plate (7) fixedly installed on the bottom inner wall of the detection chamber (2). A guide rod (8) is fixedly installed on the bottom inner wall of the detection chamber (2). The top end of the guide rod (8) is slidably connected to a pressure cylinder (9). A spring (10) is fixedly connected between the pressure cylinder (9) and the bottom inner wall of the detection chamber (2). A flexible shielding curtain (11) is provided on the outer wall of the pressure cylinder (9). Six sets of arc-shaped push plates (13) are hinged to the side wall of the pressure cylinder (9) through six sets of pressure rods (12). A rubber ring (14) is sleeved on the outer surface of the six sets of arc-shaped push plates (13). A wave groove (15) is opened on the outer wall of the rubber ring (14).

2. The device for detecting the permeability of the brake disc casting sand according to claim 1, characterized in that: The bottom center inner wall of the detection cavity (2) is provided with a circular hole with a diameter that matches the outer diameter of the pressure cylinder (9), and the pressure cylinder (9) slides in conjunction with the circular hole.

3. The device for detecting the permeability of the brake disc casting sand according to claim 1, characterized in that: The sealing disc (7) has a through hole with a diameter larger than the outer diameter of the pressure cylinder (9) at its axis, and a flexible shielding curtain (11) is placed on top of the through hole and completely covers it. The inner surface of the top of the through hole is rounded.

4. The device for detecting the permeability of the brake disc casting sand according to claim 1, characterized in that: The guide rod (8) is square in shape, and a square hole with a length greater than that of the guide rod (8) is opened at the bottom center of the pressure cylinder (9), and the guide rod (8) slides in conjunction with the square hole.

5. The device for detecting the permeability of the brake disc casting sand according to claim 1, characterized in that: The wave groove (15) is arranged in a circular shape on the side of the rubber ring (14) away from the arc-shaped push plate (13), and the wave groove (15) is evenly distributed on the upper and lower sides of the horizontal central axis of the rubber ring (14).

6. The device for detecting the permeability of the brake disc casting sand according to claim 1, characterized in that: The rubber ring (14) has a hollow cavity (6) inside, and a number of reinforcing ribs (16) are fixedly installed in a circumferential array on the inner surface of the hollow cavity (6).

7. The device for detecting the permeability of the brake disc casting sand according to claim 6, characterized in that: The cross-section of the hollow cavity (6) is configured as a gourd shape including a wide diameter end and a narrow diameter end, and the narrow diameter end of the hollow cavity (6) is located on the side close to the arc-shaped push plate (13).

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