Conformal chilling block for band-type brake nut and casting system comprising same

Abstract

The utility model discloses a shape follow-up chilling block for a band-type brake nut and a casting system comprising the shape follow-up chilling block. The chilling block structurally comprises a chilling block body capable of being matched with the inner walls of a first semicircular gate plate and a second semicircular gate plate of a band-type brake nut casting cavity. The peripheral wall of the chilling block body is attached to the inner wall of the first semicircular gate plate and the inner wall of the second semicircular gate plate. Reinforcing ribs are arranged on the inner side wall of the chilling block body, and the reinforcing ribs are arranged in the molding sand; the scheme has the advantages that the inner hole of the band-type brake nut is directly formed in the outer die, a sand core does not need to be manufactured, the production cost can be reduced, the production efficiency can be improved, and meanwhile the problems that the shape follow-up chilling block is difficult to fix and the chilling block is prone to falling off during drawing, hoisting or overturning are solved.

Description

Technical Field

[0001] The present application relates to the field of casting technology, and in particular to a conformal chiller for a brake nut and a casting system containing the same. Background Art

[0002] The clamping mechanism of the two-platen injection molding machine is two-platen, the front platen is fixed, the movable platen is movable, the four tie rods are open with ring grooves or teeth, the front platen is fixed with four clamping cylinders and two fast mold shifting cylinders, the piston rod of the fast mold shifting cylinder is connected to the movable platen, the piston rod of the clamping cylinder is also a high-pressure clamping tie rod, when the mold is in place, the opening and closing brake nut is interlocked with the tie rod ring teeth, the high-pressure oil builds up high pressure, and the clamping function is realized. The brake nut is a key part in the two-platen injection molding machine, and the threaded part is most prone to fracture and damage, so the strength of the threaded part directly affects the service life of the entire equipment.

[0003] like Figure 1 The figure shows a brake nut casting product (brake nut casting or brake nut casting cavity). The blank weight of the casting product is 560Kg, the overall dimensions are 530mm×492mm×446mm, and the material is ductile iron QT500-7A, with a maximum wall thickness of 170mm. A complete brake nut is composed of two semicircular gate plates. The brake nut is fixed to the cylinder barrel and piston rod of the brake cylinder respectively. Under the push of the cylinder, it moves along the horizontal track to complete the brake and open the brake. However, due to the thick wall thickness of the brake nut casting, it cools slowly, which is prone to casting defects such as shrinkage cavities and shrinkage.

[0004] In addition, if Figure 1 As shown, two semicircular gate plates cooperate with each other to form the inner hole of the brake nut. In the casting process, the inner hole is generally formed by a sand core, and then a conformable chill is placed in the sand core to speed up the cooling of the part and solve the shrinkage cavity and shrinkage problems of the casting. However, the conformable chill of this traditional structure is difficult to fix, and the chill is prone to fall off during demoulding, lifting or flipping. The fallen chill needs to be repaired and fixed in the original position, which greatly reduces the efficiency of casting and is difficult to meet the process requirements. In serious cases, it affects the subsequent processes. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the present application provides a brake nut having an inner hole formed directly on an outer mold without making a sand core, thereby reducing production costs and improving production efficiency. At the same time, it solves the problems of difficulty in fixing the conformable chiller and the easy falling off of the chiller during demoulding, lifting or flipping.

[0006] In order to solve the above-mentioned technical problems, the technical solution adopted in the present application is: a conformal chill for a brake nut, the structure of the chill includes a chill body that can be adapted to the inner walls of the first semicircular gate plate and the second semicircular gate plate in the brake nut casting cavity, the outer peripheral wall of the chill body and the inner walls of the first semicircular gate plate and the second semicircular gate plate are in contact with each other; reinforcing ribs are arranged on the inner side wall of the chill body, and the reinforcing ribs are arranged inside the molding sand.

[0007] By adopting the above structure, the present application directly forms the inner core structure of the brake nut casting by setting a cold iron structure that is in contact with the inner walls of the first semicircular gate plate and the second semicircular gate plate. During pouring, the molten iron directly contacts the cold iron and forms the inner core after solidification. This structure can quickly cool the brake nut casting and reduce the occurrence of casting defects. Moreover, it is a direct cold iron structure to form the inner core, and no additional sand core structure is required. More importantly, the cold iron body of the present application is provided with reinforcing ribs inside, and the reinforcing ribs are arranged inside the molding sand, so that the strength of the cold iron is improved by the reinforcing ribs, and a stable connection with the molding sand can be achieved through the reinforcing ribs. The cold iron of this structure is easy to fix, and it is not easy for the cold iron to fall off during demolding, lifting or flipping, which greatly improves the efficiency of casting and will not affect subsequent processes.

[0008] Furthermore, two cold iron bodies are bonded to the inner walls of the first semicircular gate plate and the second semicircular gate plate, and a gap is set between the two cold iron bodies; adopting this structure, the contact area between the sand mold and the cold iron can be increased to improve its firmness, and the gap between the cold irons can provide the cold iron with expansion space in the high temperature environment during the casting process, thereby avoiding adhesion and extrusion between the two cold irons.

[0009] Furthermore, a reinforcing rib is arranged axially up and down on the inner wall of the chill body, and the reinforcing rib includes a first connecting portion vertically connected to the inner wall of the chill body and a second connecting portion extending axially; with this structure, the reinforcing rib can be in a hook state, thereby improving the connection strength between the chill and the molding sand and preventing the chill from detaching; in addition, the reinforcing rib of this structure can also be used as a hand grip handle to facilitate the movement and operation of the shape-fitting chill, and the handle is not easy to break during use, which can increase the number of uses and reduce production costs.

[0010] Furthermore, the first connecting portion is located in the middle position of the circumference of the inner wall of the first semicircular gate plate or the second semicircular gate plate, and the axial end face of the second connecting portion is lower than the axial end face of the brake nut where it is located; by adopting this structure, more molding sand can be filled around the cold iron, thereby improving the wrapping strength between the cold iron and the molding sand.

[0011] Furthermore, the first connection part and the second connection part of the reinforcing rib are both square structures, and the lateral extension width of the first connection part is 25mm~35mm, the extension width of the second connection part in the direction perpendicular to the first connection part is 25mm~30mm, the distance between the second connection part and the inner wall of the cold iron body is 35mm~50mm, and the extension length of the second connection part is 70mm~90mm.

[0012] Furthermore, an identification symbol is provided on the end surface of the chill body; with this structure, the identification symbol can include the casting product name, drawing number and the number of the chill, which facilitates the management of the chill and saves management costs.

[0013] The present application also provides a casting system for a gate nut containing the above-mentioned chiller, the casting system comprising a gate nut casting cavity buried in a molding sand box, a chiller and a pouring system connected to the casting cavity; four gate nut casting cavities are arranged in the molding sand box, and are arranged side by side in pairs, and the inner wall of the gate nut casting cavity is fitted with a chiller; the pouring system comprises a straight runner, a cross runner and an ingrown; the straight runner is vertically connected to the cross runner, the cross runner is connected to the ingrown, and the discharge port of the ingrown is connected to the platform of the gate nut casting cavity; with the above-mentioned structure, the arrangement of the entire pouring structure and the position of entering the cavity have specific settings, the ingrown is connected to the platform of the casting cavity, because the wall thickness of the casting here is relatively thick, directly entering the molten iron from here can effectively realize the smooth entry of the molten iron into the casting cavity, thereby effectively avoiding the occurrence of defects such as air rings and slag inclusions.

[0014] Furthermore, a first transition runner and a second transition runner are arranged between the cross runner and the inner runner, and the first transition runner and the second transition runner are arranged up and down, and a foam filter is arranged between the two; the above structure can further prevent the occurrence of defects such as air rings and slag inclusions, and ensure the quality of molten iron; in addition, the molten iron passes through the local enlargement of the first transition runner and the second transition runner and the foam filter, which is more conducive to the smooth entry of the molten iron into the mold cavity and is also conducive to the floating of the slag.

[0015] Furthermore, eight ingates are provided, and one end of the eight ingates is vertically connected to the second transition ingate, and the other end is respectively connected to the platform of the brake nut casting cavity; and every two ingates are connected to a brake nut casting cavity; adopting this structure, the process yield rate can be improved (one out of four), and on the other hand, it is convenient to organize the weight of the poured molten iron and control the pouring temperature. If the pouring temperature is too low, slag inclusion defects are likely to occur, and if the pouring temperature is too high, shrinkage holes and shrinkage defects are likely to occur.

[0016] Furthermore, the pouring system adopts a bottom pouring system, and the sprue and the inner pouring channel both adopt ceramic tubes, which can reduce sand blasting defects.

[0017] Furthermore, a safety riser and an air vent are provided on the outside of the brake nut casting cavity, and each brake nut casting cavity is provided with a safety riser and an air vent; by adopting this structure, gas can be discharged in time during the pouring process, and molten iron can be replenished in time, further reducing the casting defects of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of the brake nut casting (or also referred to as the brake nut casting cavity) of the present application.

[0019] Figure 2 Schematic diagram of the structure of the conformal chiller of the present application.

[0020] Figure 3 A schematic diagram of the structure of a top view of a conformal cold iron in the present application.

[0021] Figure 4 The structural diagram of the axial cross-sectional view of the conformal cold iron of the present application ( Figure 3 Cross-sectional view in the QQ direction).

[0022] Figure 5 The present application provides a set of structural schematic diagrams of conformal chillers.

[0023] Figure 6 The present application provides a structural schematic diagram of a group of conformal chillers combined with brake nut castings.

[0024] Figure 7 Schematic diagram of the structure of the conformable chiller in the sand box of the present application.

[0025] Figure 8 Schematic diagram of the structure of the combination of form-fitting chilled iron and molding sand in the present application.

[0026] Fig. 9 The structural diagram of the first view of the pouring system of this application.

[0027] Fig.10 The structural diagram of the second view of the pouring system of this application.

[0028] Fig.11 A schematic structural diagram of the first view of the pouring system and the cavity combined in the present application.

[0029] Fig.12 A second view structural diagram of the combination of the pouring system and the cavity of the present application.

[0030] As shown in the attached drawings: 1. Brake nut casting cavity, 101. First semicircular gate plate, 102. Second semicircular gate plate, 2. Chilled iron body (conforming chilled iron), 3. Reinforcing ribs, 301. First connecting part, 302. Second connecting part, 4. Molding sand, 5. Molding sand box, 6. Straight runner, 7. Horizontal runner, 8. Inner runner, 9. First transition runner, 10. Second transition runner, 11. Foam filter, 12. Safety riser, 13. Air outlet. DETAILED DESCRIPTION

[0031] The following will combine the embodiments and drawings to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only preferred embodiments, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention;

[0032] It should also be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be another intermediate component, fixed through the intermediate component. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be another intermediate component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be another intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] The casting cavity of the present application can be the structure of the casting cavity for pouring, or the final casting structure, because the casting is obtained by first forming a cavity consistent with the casting structure, pouring molten iron in the cavity and cooling it. Therefore, the casting cavity (body) of the present application and the structure of the casting can be referred to as the same, and the structural relationship between each structure and the casting cavity body can also be seen as the structural relationship between the casting.

[0034] As attached Figure 1-6 As shown, a conformal cold iron for a brake nut of the present application is provided, and the structure of the cold iron includes a first semicircular gate plate 101 and a second semicircular gate plate 102 (specifically attached) that can be in contact with the brake nut casting cavity 1 Figure 1As shown, a complete brake nut is composed of two first semicircular gate plates 101 and second semicircular gate plates 102 that match each other symmetrically; Figure 1 What is shown is a cold iron body 2 (the outer peripheral wall of the cold iron body here is used to form the inner diameter size of the brake nut) that is adapted to the inner wall of the brake nut casting or the cavity structure forming the brake nut casting in the casting system, that is, the brake nut casting cavity), and the outer peripheral wall of the cold iron body 2 is in contact with the inner walls of the first semicircular gate plate 101 and the second semicircular gate plate 102; reinforcing ribs 3 are arranged on the inner side wall of the cold iron body 2, and the reinforcing ribs 3 are arranged inside the molding sand 4 (that is, in the sand casting process, the reinforcing ribs are buried inside the molding sand, thereby forming a stable connection with the molding sand, thereby improving the connection firmness between the conformable cold iron and the entire sand mold, and not easily falling off).

[0035] By adopting the above structure, the present application directly forms the inner core structure of the brake nut casting by setting a cold iron structure that fits mutually with the inner walls of the first semicircular gate plate and the second semicircular gate plate. During pouring, the molten iron directly contacts the cold iron and forms the inner core after solidification. This structure can enable the brake nut casting to be cooled quickly and reduce the occurrence of casting defects. More importantly, the cold iron body of the present application is provided with reinforcing ribs on its interior, and the reinforcing ribs are arranged inside the molding sand. In this way, the strength of the cold iron is improved by the reinforcing ribs, and a stable connection with the molding sand can be achieved through the reinforcing ribs. The cold iron of this structure is easy to fix, and the cold iron is not easy to fall off during demolding, lifting or flipping, which greatly improves the efficiency of casting production and will not affect subsequent processes.

[0036] As attached Figure 5-6 As shown, the inner walls of the first semicircular gate plate 101 and the second semicircular gate plate 102 described in the present application are both fitted with two chill bodies 2, and a gap is set between the two chill bodies 2 (that is, the two are not in contact, leaving a certain gap); adopting this structure, the contact area between the sand mold and the chill can be increased to improve its firmness, and the gap between the chills can provide expansion space for the chills in the high-temperature environment of the casting process, thereby avoiding adhesion and extrusion between the two chills; in addition, by setting up two chills, the inner wall of a semicircular gate plate can be differentiated, thereby avoiding thermal expansion of a whole piece of chill, resulting in changes in size that affect the quality of the casting.

[0037] As attached Figure 2-6As shown, a reinforcing rib 3 is arranged axially up and down on the inner wall of the cold iron body 2 described in the present application, and the reinforcing rib 3 includes a first connecting portion 301 vertically connected to the inner wall of the cold iron body 2 and a second connecting portion 302 extending along the axial direction; that is, a reinforcing rib of an L-shaped structure is formed; adopting this structure, the reinforcing rib can be in a hook state, thereby improving the connection firmness between the cold iron and the molding sand and preventing the cold iron from detaching; in addition, the reinforcing rib of this structure can also be used as a hand grip handle to facilitate the movement and operation of the cold iron, and the handle is not easy to break during use, which can increase the number of uses and reduce production costs.

[0038] As attached Figure 2-6 As shown, the first connecting portion 301 described in the present application is located in the middle position of the circumference of the inner wall of the first semicircular gate plate 101 or the second semicircular gate plate 102, and the axial end face of the second connecting portion 302 is lower than the axial end face of the brake nut 1 where it is located; by adopting this structure, more molding sand can be filled around the cold iron to increase the wrapping strength between the cold iron and the molding sand.

[0039] As an example, the attached Figure 2-6 As shown, the first connection portion 301 and the second connection portion 302 of the reinforcing rib 3 described in the present application are both square structures, and the lateral extension width of the first connection portion is 25 mm to 35 mm ( Figure 3 A) The extension width of the second connection portion in the direction perpendicular to the first connection portion is 25 mm to 30 mm ( Figure 4 B), the distance between the second connection part and the inner wall of the cold iron body is 35mm to 50mm ( Figure 4 h), the extension length of the second connecting portion is 70 mm to 90 mm ( Figure 4 L); the structure of the reinforcing rib 3 can be used with the present application Figure 1 The structures of the brake nut casting shown are adapted to each other to form the inner diameter of the casting and the overall shape of the casting.

[0040] As an example, an identification symbol is set on the end face of the cold iron body 2 described in the present application; with this structure, this identification symbol can include the casting product name, drawing number and the number of the cold iron, which facilitates the management of the cold iron and saves management costs.

[0041] As attached Figure 9-12 As shown, the present application also provides a casting system for a brake nut containing the above-mentioned cold iron, the casting system includes a brake nut casting cavity 1 (also referred to as a brake nut 1 or a brake nut casting) buried in a molding sand box 5, a cold iron body 2 (that is, the above-mentioned conformal cold iron structure of the present application) and a pouring system connected to the brake nut casting cavity 1; the molding sand box 5 (the molding sand box of the present application is composed of an upper box and a lower box mold, refer to the attached Figure 7As shown, the molding sand is filled in the box to form a casting cavity and a pouring system, and the chiller is fixed at a set position; Figure 7-8 The structure of the sand box is shown. After the pouring system, cavity and cold iron structure of the sand box of this application are determined, the sand box molding process can be the conventional process in the industry. The sand box of this application is finally formed by combining high temperature resistant molding sand with a binder. Figure 7-8 Four brake nut casting cavities 1 are arranged in the molding sand box body shown in the figure, and are arranged side by side in pairs (i.e., Figure 7-8 The arrangement shown is that four are arranged in one sand box), the inner wall of the brake nut casting cavity 1 is fitted with a cold iron body 2; the casting system includes a straight runner 6, a cross runner 7 and an ingrown runner 8 which are interconnected; the straight runner 6 is vertically connected to the cross runner 7, the cross runner 7 is connected to the ingrown runner 8, and the discharge port of the ingrown runner 8 is connected to the platform of the brake nut casting cavity 1 (that is, the side wall in the radial direction of the first semicircular gate plate or the second semicircular gate plate); with the above structure, the arrangement of the entire casting structure and the position of entering the cavity have specific settings, the ingrown runner is connected to the platform of the casting cavity, because the wall thickness of the casting here is thicker, directly entering the molten iron from here can effectively realize the smooth entry of the molten iron into the casting cavity, thereby effectively avoiding the occurrence of defects such as air rings and slag inclusions.

[0042] As attached Figure 9-12 As shown, a first transition runner 9 and a second transition runner 10 are further arranged between the cross runner 7 and the inner runner 8 described in the present application. The first transition runner 9 and the second transition runner 10 are arranged up and down, and a foam filter 11 is arranged between the two (manufacturer: Jinan Shengquan Group Co., Ltd.); the above structure can further prevent the occurrence of defects such as air rings and slag inclusions, and ensure the quality of molten iron; in addition, the molten iron passes through the local enlargement of the first transition runner and the second transition runner and the foam filter, which is more conducive to the smooth entry of the molten iron into the mold cavity and is also conducive to the floating of the slag.

[0043] As attached Figure 9-12As shown, the ingates 8 described in the present application are provided with eight, and one end of the eight ingates 8 is vertically connected to the second transition runner 10, and the other end is respectively connected to the platform of the brake nut casting cavity 1; and every two ingates 8 are connected to a brake nut casting cavity 1; adopting this structure, the process yield rate can be improved (one out of four), and on the other hand, it is convenient to organize the weight of the poured molten iron and control the pouring temperature. If the pouring temperature is too low, slag inclusion defects are likely to occur, and if the pouring temperature is too high, shrinkage cavities and shrinkage defects are likely to occur; the cross section of the straight runner is circular, and the cross section of the horizontal runner is The pouring surface is square so that the poured molten iron can quickly enter the cross runner. Two transition runners are arranged at the discharge tail end of the cross runner. The transition runner is a three-dimensional trapezoidal structure. Eight ingates are connected to the bottom surface of the second transition runner. The eight ingates are composed of vertical short runners and horizontally extended long runners, and the parts connected thereto at both ends are perpendicular; and the connecting ends of the eight ingates and the casting cavity are dispersedly arranged, so that two groups are connected to a casting cavity; the above-mentioned system is a bottom pouring system, which can guide the molten iron into the cavity more smoothly and reduce casting defects.

[0044] As an example, the pouring system described in the present application adopts a bottom pouring system (i.e., the molten iron gradually flows upward from the bottom of the cavity until it fills the entire cavity). The straight runner and inner runner described in the present application both adopt high-temperature resistant ceramic tubes, which are pre-buried in the molding sand according to the structure of the pouring system, thereby reducing sand blasting defects.

[0045] As attached Figure 11-12 As shown, a safety riser 12 and an air outlet 13 (flat air outlet) are provided on the outside of the brake nut casting cavity 1 described in the present application, and each brake nut casting cavity 1 is provided with a safety riser 12 and an air outlet 13; with this structure, the gas can be discharged in time during the pouring process, and the molten iron can be replenished in time, so as to further reduce the casting defects of the casting; Figure 11-12 The specific position of the chill is not shown. The chill is located in the pouring system. Figure 6 , 7 And the method shown in 8 can be fixed in the sand box by the molding sand.

[0046] The casting system of the present application can produce four semicircular gates, each of which cooperates with each other to form a Figure 1 The complete brake nut shown; effectively improves casting efficiency.

[0047] The above-mentioned technical solution of the present application is to directly form the inner hole of the brake nut on an external mold (that is, the part of the sand box that covers the outside of the casting cavity) without the need to make an additional sand core. The inner hole can be formed by the cooperation of two pieces of chiller bodies. Therefore, it can reduce production costs and improve production efficiency, while solving the problems of difficulty in fixing the conformable chiller and the easy falling off of the chiller during demolding, lifting or flipping.

Claims

1. A conformal chiller for a brake nut, characterized in that: The structure of the chiller includes a chiller body that can be adapted to the inner walls of the first semicircular gate plate and the second semicircular gate plate in the cavity of the brake nut casting, and the outer peripheral wall of the chiller body is in contact with the inner walls of the first semicircular gate plate and the second semicircular gate plate; reinforcing ribs are arranged on the inner side wall of the chiller body, and the reinforcing ribs are arranged inside the molding sand.

2. The conformal chiller for a brake nut according to claim 1, characterized in that: Two cold iron bodies are attached to the inner walls of the first semicircular gate plate and the second semicircular gate plate, and a gap is provided between the two cold iron bodies.

3. The conformal chiller for a brake nut according to claim 1, characterized in that: A reinforcing rib is arranged on the inner wall of the cold iron body in the upper and lower directions along the axial direction, and the reinforcing rib comprises a first connecting portion vertically connected to the inner wall of the cold iron body and a second connecting portion extending in the axial direction.

4. The conformal chiller for a brake nut according to claim 3, characterized in that: The first connecting portion is located at the middle position of the inner wall of the first semicircular gate plate or the second semicircular gate plate in the circumferential direction, and the axial end face of the second connecting portion is lower than the axial end face of the brake nut where it is located.

5. The conformal chiller for a brake nut according to claim 3, characterized in that: The first connection part and the second connection part of the reinforcing rib are both square structures, and the lateral extension width of the first connection part is 25mm~35mm, the extension width of the second connection part in the direction perpendicular to the first connection part is 25mm~30mm, the distance between the second connection part and the inner wall of the cold iron body is 35mm~50mm, and the extension length of the second connection part is 70mm~90mm.

6. The conformal chiller for a brake nut according to claim 3, characterized in that: An identification symbol is arranged on the end surface of the cold iron body.

7. A casting system comprising a conformal chill for a brake nut according to any one of claims 1 to 6, characterized in that: The casting system includes a brake nut casting cavity buried in a molding sand box, a chiller and a pouring system connected to the casting cavity; four brake nut casting cavities are arranged in the molding sand box, and two are arranged side by side, and the inner wall of the brake nut casting cavity is attached with a chiller; the pouring system includes a straight runner, a cross runner and an ingode; the straight runner is vertically connected to the cross runner, the cross runner is connected to the ingode, and the discharge port of the ingode is connected to the platform of the brake nut casting cavity.

8. The casting system according to claim 7, characterized in that: A first transition runner and a second transition runner are also arranged between the cross runner and the inner runner. The first transition runner and the second transition runner are arranged up and down, and a foam filter is arranged between the two.

9. The casting system according to claim 7, characterized in that: There are eight ingates, one end of which is vertically connected to the second transition ingate, and the other end is respectively connected to the platform of the brake nut casting cavity; and every two ingates are connected to one brake nut casting cavity.

10. The casting system according to claim 7, characterized in that: The pouring system adopts a bottom pouring system, and the sprue and the inner pouring channel both adopt ceramic tubes; a safety riser and an air outlet are arranged on the outer side of the brake nut casting cavity, and each brake nut casting cavity is respectively provided with a safety riser and an air outlet.

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