A lightweight brake shoe and sand casting mold

Abstract

The present invention relates to the technical field of casting brake shoes, and in particular to a lightweight brake shoe and sand casting mold, wherein the mold comprises a male mold and a female mold for forming a sand mold, wherein the surface of the male mold is provided with a first convex block, a first pouring cup and a runner system, wherein the first convex block is provided with a first casting mold, wherein the runner system comprises a cross runner, an inner runner and an inner gate, wherein the cross runner is connected to the first pouring cup, wherein the inner gate is located at the upper end of the first boss and is correspondingly arranged between the two ribs of the brake shoe; wherein the female mold comprises a second template, wherein the surface of the second template is provided with a first groove and a second pouring cup, wherein a plurality of second casting molds are arranged inside the first groove. The inner gate of the present invention is arranged at the upper end of the shoe plate of the brake shoe and between the two ribs, so that during casting, from bottom to top, the molten metal can first fill the large shoe plate and then the small rib plate, thereby avoiding the problem of cold shut shrinkage and reducing the processing procedures of the brake shoe.

Description

Technical Field

[0001] The invention relates to the technical field of brake shoe casting, in particular to a lightweight brake shoe and a sand casting mold. Background Art

[0002] The brake shoe refers to the brake accessory that is pushed outward and presses the brake drum by the brake cam or push rod to achieve braking effect. It is installed on the brake drum and is one of the key safety components in the automobile braking system.

[0003] Brake shoes are divided into cast shoes and welded brake shoes. Welded brake shoes have defects such as poor rigidity, low heat capacity, easy deformation due to overheating during operation, and large adjustment gap. Cast shoes are better than welded brake shoes in stability, rigidity and wear resistance. Therefore, cast shoes are more commonly used than welded brake shoes.

[0004] The sand casting process of the shoe includes preparing a sand mold with a cavity by using a sand casting mold, and then injecting liquid metal into the mold cavity by sequentially passing through the runner system and the gate of the sand mold, and obtaining the blank of the shoe after cooling. In the prior art, there are two main problems in the sand casting process of the shoe. First, during sand casting, a gate is usually set on the outer arc surface of the shoe plate or on the inner arc surface of the rib plate, and the obtained blank has a casting parting surface formed on the center line of the shoe plate and the rib plate. In this way, not only the machining allowance needs to be increased during casting, but also the subsequent machining steps of the brake shoe are increased, such as the machining of the outer arc surface of the brake shoe plate; second, the design of the mold used to produce the casting sand mold is unreasonable. During pouring, the flow stability of the molten metal in the mold cavity of the brake shoe is poor, and the casting is prone to problems such as cold shut and shrinkage, thereby reducing the quality of the casting. Summary of the invention

[0005] The purpose of the present invention is to provide a lightweight brake shoe and a sand casting mold to address the deficiencies of the prior art. The design of the lightweight brake shoe and the sand casting mold are reasonable, and the problems of cold shut and shrinkage during brake shoe casting can be effectively solved, thereby reducing the processing steps of the brake shoe.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a sand casting mold for a lightweight brake shoe, comprising a male mold and a female mold, the male mold comprising a first template, the surface of the first template is provided with a first convex block, a first pouring cup and a runner system, along the length direction of the first template, the surface of the first convex block is provided with a plurality of first casting molds for forming a shoe plate cavity of the brake shoe, the runner system is located between the first pouring cup and the first convex block, the runner system comprises a cross runner, an ingate and an ingate, the cross runner is connected to the first pouring cup, the ingate is located at the upper end of the first boss, and is correspondingly arranged between the two ribs of the brake shoe, one end of the ingate is connected to the cross runner, and the other end is connected to the ingate;

[0007] The die includes a second template, and a first groove and a second pouring cup are arranged on the surface of the second template. The first groove is arranged corresponding to the first protrusion, and the second pouring cup is arranged corresponding to the first pouring cup. A plurality of second casting molds are arranged inside the first groove, and the second casting molds are arranged corresponding to the first casting mold. The second casting mold includes a rib plate casting for forming a rib plate cavity and a shoe plate casting of a certain thickness for forming a shoe plate cavity, and both ends of the rib plate casting are higher than the surface of the second template.

[0008] Furthermore, the surface of the first protrusion is an arc surface, the curvature of the arc surface of the first protrusion is equal to the curvature of the shoe plate of the brake shoe, the first casting protrudes from the arc surface of the first protrusion, and the thickness of the first casting is 0 to one third of the thickness of the shoe plate of the brake shoe.

[0009] Furthermore, the second template is provided with a plurality of second bosses, the second bosses are located at the two ends of the rib plate casting, the top of the second bosses is not higher than the two ends of the rib plate casting, the first template is provided with a plurality of second grooves, the second bosses are arranged corresponding to the second grooves, and the inner runner is located between the two second grooves.

[0010] Furthermore, the height of the ingates is smaller than the height of the second bosses.

[0011] On the other hand, a lightweight brake shoe includes an arc-shaped shoe plate and two arc-shaped and parallel rib plates, the rib plate is located on the inner side of the shoe plate, the shoe plate and the rib plate are cast as one piece, a plurality of reinforcing ribs are arranged on the inner arc surface of the shoe plate, the reinforcing ribs include a plurality of transverse reinforcing ribs and a plurality of longitudinal reinforcing ribs, the transverse reinforcing ribs are perpendicular to the rib plates, the longitudinal reinforcing ribs are parallel to the arc surface of the rib plates, arc-shaped notches for connecting the drive shaft are arranged at both ends of the rib plates, a plurality of heat dissipation holes are arranged on the shoe plate, and connecting ribs are arranged between the rib plates.

[0012] Furthermore, a plurality of third grooves are arranged on the outer side surface of the shoe plate, and the third grooves are arranged corresponding to the transverse reinforcing ribs. Both ends of the third grooves penetrate through the two side surfaces of the shoe plate, and the third grooves are open at both ends.

[0013] Furthermore, the thickness at both ends of the rib plate is greater than the thickness in the middle of the rib plate, and the thickness of the rib plate gradually decreases from the two ends of the rib plate to the middle of the rib plate.

[0014] The beneficial effects of the present invention are:

[0015] 1. During vertical split casting, the present invention prepares two halves of the sand mold of the brake shoe by a male mold and a female mold, and then obtains a casting cavity with a brake shoe cavity by combining the two halves of the sand core, wherein the inner gate of the casting cavity is located at the upper end of the shoe plate cavity and between the two ribs. During casting, the molten metal can fill the brake shoe cavity from top to bottom along the arc-shaped shoe plate and rib plate, thereby avoiding sand holes in the casting caused by sand flushing during molten metal filling. At the same time, during casting, in the same horizontal plane of the casting cavity, the molten metal can first enter the large surface (i.e., enter the shoe plate cavity first) and then the small surface (i.e., enter the rib plate cavity later), thereby ensuring smooth circulation of the molten metal in the brake shoe cavity, avoiding cold shut phenomenon, and improving the casting quality of the brake shoe.

[0016] 2. The concave mold and the convex mold are respectively provided with a second boss and a second groove. On the one hand, the rib plate structure of the brake shoe is used to form a barb on the sand mold on one side of the cavity, so that when the casting is separated from the sand mold, the barb can hook the casting from the sand mold on the other side, which is convenient for separating the casting from the sand mold; on the other hand, since the two ends of the rib plate of the brake shoe protrude from the surface of the second template, the second boss is provided at both ends of the rib plate casting, which is conducive to reducing the draft thickness of the sand mold at both ends of the rib plate, avoiding the problems of cold shut and shrinkage cavity that affect the casting during casting, and is conducive to improving the quality of the casting; in addition, after the two sand molds are molded together, the ingrowth is located between the raised sand molds formed by the second groove, which is conducive to preventing the metal liquid in the ingrowth from cooling down quickly, so that the metal in the ingrowth can compensate for the shrinkage of the casting, and no additional riser is required for compensation, which is conducive to realizing riser-free casting. At the same time, the first template is provided with a second groove, and the second template is provided with a second boss. The second boss cooperates with the second groove, which is conducive to ensuring the mold closing accuracy of the sand mold and further ensuring the quality of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 It is a structural schematic diagram of an embodiment of the punch of the present invention.

[0019] Figure 3 It is a schematic structural diagram of a second embodiment of the punch of the present invention.

[0020] Figure 4 It is a structural schematic diagram of the concave mold of the present invention.

[0021] Figure 5 It is a side view of the concave mold of the present invention.

[0022] Figure 6 It is a structural schematic diagram of the lightweight brake shoe of the present invention.

[0023] Figure 7 It is a structural schematic diagram of the lightweight brake shoe of the present invention.

[0024] Figure 8 It is a schematic diagram of the casting structure obtained by the present invention.

[0025] Description of reference numerals:

[0026] 10——punch, 101——first template, 102——first projection, 103——first pouring cup, 104——first mold, 105——cross runner, 106——ingress, 107——ingress, 108——second groove, 20——die, 201——second template, 202——first groove, 203——second mold, 2031——rib plate mold, 2032——shoe plate mold, 204——second boss, 30——brake shoe, 301——rib plate, 302——shoe plate, 303——reinforcement rib, 3031——transverse reinforcement rib, 3032——longitudinal reinforcement rib, 304——arc notch, 305——connecting rib, 306——third groove. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the implementation scope of the present invention is not limited thereto.

[0028] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] like Figures 1 to 8 As shown, a casting mold for a lightweight brake shoe of this embodiment includes a male mold 10 and a female mold 20 for forming a casting sand mold cavity. The male mold 10 is used to prepare a sand mold for forming half of the brake shoe cavity, and the female mold 20 is used to prepare a sand mold for forming the other half of the brake shoe cavity.

[0031] The punch 10 includes a first template 101, and the surface of the first template 101 is provided with a first convex block 102, a first pouring cup 103 and a runner system. The surface of the first convex block 102 is a curved surface, and the curvature of the curved surface of the first convex block 102 is equal to the curvature of the shoe plate of the brake shoe 30, that is, the curvature and arc length of the curved surface of the first convex block 102 are consistent with the curvature and arc length of the shoe plate 302 of the brake shoe 30. Along the length direction of the first template 101, the surface of the first convex block 102 is provided with a plurality of first casting molds 104 for forming the shoe plate cavity of the brake shoe 30. The first casting mold 104 protrudes from the curved surface of the first convex block 102, and the thickness of the first casting mold 104 is less than the thickness of the shoe plate 302 of the brake shoe 30. Preferably, the thickness of the first casting mold 104 is 0 mm to one third of the thickness of the shoe plate 302 of the brake shoe 30. Figure 2 It is a schematic diagram of the first casting mold 104 with a thickness of 0, the runner system is located between the first pouring cup 103 and the first protrusion 102, the runner system includes a runner 105, an ingate 106 and an ingate 107, the runner 105 is connected to the first pouring cup 103, that is, the cavity of the runner 105 is connected to the cavity of the first pouring cup 103, the ingate 107 is located at the upper end of the first boss, and is correspondingly arranged between the two ribs 301 of the brake shoe 30, after the two half sand molds prepared by the punch 10 and the die 20 are molded together, the ingate 107 is located at the upper end of the shoe plate cavity, between the two rib plate cavities, and is connected to the shoe plate cavity; one end of the ingate 106 is connected to the runner 105, and the other end is connected to the ingate 107, and the connection of the present invention means that after the cavity is formed, the cavity of each structure is in a connected state;

[0032] The die 20 includes a second template 201, and the surface of the second template 201 is provided with a first groove 202, a second pouring cup and a second mold 203. The first groove 202 is arranged corresponding to the first protrusion 102, and the second pouring cup is symmetrically arranged with the first pouring cup 103. The second mold 203 is located in the first groove 202 and is symmetrically arranged with the first mold 104. The second mold 203 includes a rib plate mold 2031 and a shoe plate mold 2032 of a certain thickness, that is, the second mold 203 includes a shoe plate structure of a certain thickness and all structures on the inner side of the shoe plate arc surface, and both ends of the rib plate mold 2031 are higher than the surface of the second template 201. The casting process of the present invention is to prepare two left and right sand molds respectively through a punch 10 and a groove, and after the two sand molds are combined, a complete casting cavity, a runner cavity and a pouring cup cavity are formed. The molten metal enters the casting cavity through the pouring cup cavity, the runner cavity and the inner gate 107 of the casting cavity in turn, and a blank of the casting is obtained after cooling.

[0033] like Figure 1-Figure 5As shown, the second template 201 is provided with a plurality of second bosses 204, and the second bosses 204 are located at both ends of the rib plate casting 2031. The top of the second boss 204 is not higher than the two ends of the rib plate casting 2031. The first template 101 is provided with a plurality of second grooves 108. The second bosses 204 are arranged corresponding to the second grooves 108. The ingates 106 are located between the two second grooves 108. The height of the ingates 106 is less than the height of the second groove 108 or the second boss 204. On the one hand, by utilizing the structure of the rib plate 301 of the brake shoe 30, a barb is formed in the sand mold on one side of the cavity, so that when the sand molds on both sides are separated, the barb acts on the outer side of the rib plate 301 of the blank casting, and the casting can be hooked up from the sand mold on the other side, which facilitates the separation of the casting from the sand mold; on the other hand, since both ends of the rib plate 301 of the brake shoe 30 protrude from the surface of the second template 201, second bosses 204 are provided at both ends of the rib plate casting 2031, which is beneficial to reducing the draft thickness of the sand molds at both ends of the rib plate 301, avoiding problems such as cold shut and shrinkage holes that affect the casting of the casting during casting, and is beneficial to improving the quality of the casting; in addition, after the two sand molds are molded together, the ingrowth 106 is located between the raised sand molds formed by the second groove 108, which can prevent the molten metal in the ingrowth 106 from cooling down quickly, so that the molten metal in the ingrowth 106 can compensate for the shrinkage of the casting, and there is no need to additionally set up a riser or shrinkage pack for shrinkage compensation, which is beneficial to achieve riserless casting. Furthermore, the first template 101 is provided with a second groove 108, and the second template 201 is provided with a second boss 204. The sand mold structure formed by the second boss 204 and the second groove 108 can cooperate with each other, which is beneficial to ensure the mold accuracy of the sand mold and further guarantee the quality of the casting.

[0034] The second boss 204 is provided with a draft angle to facilitate the separation of the sand mold.

[0035] On the other hand, Figure 6 and Figure 7 As shown, a lightweight brake shoe comprises an arc-shaped shoe plate 302 and two arc-shaped and parallel rib plates 301, the rib plate 301 is located on the inner side of the shoe plate 302, the shoe plate 302 and the rib plate 301 are integrally cast, a plurality of reinforcing ribs 303 are arranged on the inner arc surface of the shoe plate 302, the reinforcing ribs 303 comprise a plurality of transverse reinforcing ribs 3031 and a plurality of longitudinal reinforcing ribs 3032, the transverse reinforcing ribs 3031 are perpendicular to the rib plates, the longitudinal reinforcing ribs 3032 are parallel to the arc surface of the rib plates, arc-shaped notches 304 for connecting the drive shaft are arranged at both ends of the rib plates, a plurality of heat dissipation holes are arranged on the shoe plate 302, and connecting ribs 305 are arranged between the rib plates 301.

[0036] The outer side surface of the shoe plate 302 is provided with a plurality of third grooves 306, and the third grooves 306 are provided corresponding to the transverse reinforcing ribs 3031. The two ends of the third grooves 306 penetrate the two side surfaces of the shoe plate 302, and are grooves with open ends. During casting, a core for forming the third grooves 306 can be placed at the corresponding position of the cavity, or a plurality of structures for forming the third grooves 306, such as grooves, can be provided on the surface of the first casting mold 104. The thickness of the reinforcing ribs 303, that is, the wall thickness of the third grooves 306, is greater than 0.5 times the thickness of the shoe plate 302. The outer side of the shoe plate 302 is connected to the friction plate. By providing a plurality of third grooves 306 on the outer side surface of the shoe plate 302, a gap is formed between the friction plate and the shoe plate 302, which is convenient for heat dissipation of the brake shoe and improves the heat dissipation efficiency.

[0037] The thickness of the two ends of the rib plate 301 is greater than the thickness of the middle part of the rib plate 301. The side of the transition section where the rib plate 301 transitions from the thicker section to the middle part is an inclined surface or a smooth arc surface, and the non-right angle or step corner can facilitate the full filling of the rib plate 301 during casting, ensure the flow stability of the molten metal, avoid shrinkage of the rib plate 301, and help to ensure the quality of the casting.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A casting mold for a lightweight brake shoe, characterized in that: It comprises a male mold (10) and a female mold (20) for forming a casting cavity; The punch (10) comprises a first template (101), the surface of the first template (101) is provided with a first convex block (102), a first pouring cup (103) and a runner system, along the length direction of the first template (101), the surface of the first convex block (102) is provided with a plurality of first casting molds (104) for forming a shoe plate cavity of a brake shoe, the runner system is located between the first pouring cup (103) and the first convex block (102), the runner system comprises a cross runner (105), an ingate (106) and an ingate (107), the cross runner (105) is connected to the first pouring cup (103), the ingate (107) is located at the upper end of the first convex block (102) and is correspondingly arranged between two ribs (301) of the brake shoe (30), one end of the ingate (106) is connected to the cross runner (105), and the other end is connected to the ingate (107); The concave mold (20) comprises a second template (201), a first groove (202) is arranged on the surface of the second template (201), the first groove (202) is arranged corresponding to the first protrusion (102), a plurality of second casting molds (203) are arranged inside the first groove (202), the second casting molds (203) are arranged corresponding to the first casting mold (104), the second casting mold (203) comprises a rib plate casting mold (2031) and a shoe plate casting mold (2032), and both ends of the rib plate casting mold (2031) are higher than the surface of the second template (201); The second template (201) is provided with a plurality of second bosses (204), the second bosses (204) are located at the two ends of the rib plate casting, the top of the second bosses (204) is not higher than the two ends of the rib plate casting (2031), the first template (101) is provided with a plurality of second grooves (108), the second bosses (204) and the second grooves (108) are arranged correspondingly, and the inner runner (106) is located between the two second grooves (108).

2. A casting mold for a lightweight brake shoe according to claim 1, characterized in that: The surface of the first protrusion (102) is an arc surface, and the curvature of the arc surface of the first protrusion (102) is consistent with the curvature of the shoe plate (302) of the brake shoe (30).

3. The casting mold of a lightweight brake shoe according to claim 1, characterized in that: The thickness of the first casting mold (104) is 0 to one third of the thickness of the shoe plate (302) of the brake shoe (30).

4. The casting mold for a lightweight brake shoe according to claim 1, characterized in that: The height of the ingrate (106) is smaller than the height of the second boss (204).

5. A lightweight brake shoe obtained by a casting mold for a lightweight brake shoe according to any one of claims 1 to 4, characterized in that: The invention comprises an arc-shaped shoe plate (302) and two arc-shaped and parallel rib plates (301), wherein the shoe plate (302) and the rib plate (301) are integrally cast, and a plurality of reinforcing ribs (303) are arranged on the inner arc surface of the shoe plate (302), wherein the reinforcing ribs (303) comprise a plurality of transverse reinforcing ribs (3031) and a plurality of longitudinal reinforcing ribs (3032), wherein the transverse reinforcing ribs (3031) are perpendicular to the rib plate (301), and the longitudinal reinforcing ribs (3032) are parallel to the arc surface of the rib plate (301), and arc-shaped notches (304) for connecting a drive shaft are arranged at both ends of the rib plate (301), and connecting ribs (305) are arranged between the rib plates (301).

6. A lightweight brake shoe according to claim 5, characterized in that: A plurality of third grooves (306) are provided on the outer side surface of the shoe plate (302), the third grooves (306) are provided corresponding to the transverse reinforcing ribs (3031), and two ends of the third grooves (306) pass through the two side surfaces of the shoe plate (302).

7. The lightweight brake shoe according to claim 5, characterized in that: The thickness of the two ends of the rib plate (301) is greater than the thickness of the middle portion of the rib plate (301), and the thickness of the rib plate (301) gradually decreases from the two ends of the rib plate (301) to the middle portion of the rib plate (301).

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