Multi-station cold heading forging module for caliper piston and cold heading forging process

Abstract

The present invention relates to the technical field of caliper piston processing, in particular to a multi-station cold heading forging module for caliper pistons and a cold heading forging forming process. The cold heading forging module includes: a first main die, a second main die, a third main die, a fourth main die; and a fifth main die. In the present invention, after the blank is successively cold headed and shaped by the first main die and the second main die, the defects such as tiny hollows and cracks existing inside the blank are eliminated, and the internal structure of the blank becomes uniform and compact. Then, it is leveled by the third main die to further improve the internal structure of the blank and make it ready for positioning. Next, a positioning recess is cold headed by the fourth main die. Finally, the inner hole and the card slot of the blank are formed at one time by the fifth main die, thereby effectively reducing the forming process of the piston, improving the production efficiency, and achieving the advantages of high forming accuracy of the piston through five times of cold heading forming, and ensuring that there are no defects in the card slot formed at the bottom of the piston, improving the quality of the piston.

Description

Technical Field

[0001] The present invention relates to the technical field of caliper piston processing, in particular to a multi-station cold heading forging module for caliper pistons and a cold heading forging process. Background Art

[0002] A brake caliper is a component attached to the front and rear of a brake disc. There is one or more pistons in the brake caliper. When the brake pedal is depressed, pressure is generated, forcing the brake fluid to push the pistons, which in turn push the brake pads inward to clamp the brake disc to achieve the effect of braking and decelerating. Therefore, the piston is one of the core components in the caliper, and the quality of the piston will directly affect the quality of the caliper.

[0003] The structure of the caliper piston is as Figure 5 shown. One end of the piston 8 has an inner hole 801, and the other end has a card slot 802. Regarding the manufacture of the piston in the caliper, at present, many attempts have been made in China to form it through a mold, but all have ended in failure. Only by using a hydraulic press or a punching machine for repeated stamping, the required processes for forming are more, the production efficiency is low, and the quality cannot be controlled within the best tolerance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to solve the problem that the piston of the caliper in the prior art can only be completed by repeated stamping with a hydraulic press or a punching machine, the required processes for forming are more, the production efficiency is low, and the machining accuracy cannot be guaranteed. Now, a multi-station cold heading forging module for caliper pistons and a cold heading forging process are provided.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a multi-station cold heading forging module for caliper pistons, which is used to cold head a blank into a piston. The cold heading forging module includes:

[0006] A first main die, having a first cavity, above which a first punch rod is provided, and the first punch rod is opposed to the front surface of the blank in the first cavity;

[0007] A second main die, having a second cavity, above which a second punch rod is provided. The second main die is used to cold head the blank cold headed by the first main die, and the second punch rod is opposed to the back surface of the blank in the second cavity;

[0008] A third main die, having a third cavity, above which a third punch rod is provided. The third main die is used to cold head the blank cold headed by the second main die, and the third punch rod is opposed to the front surface of the blank in the third cavity;

[0009] The fourth main die has a fourth cavity. Above the fourth cavity, there is a fourth punch rod, which is opposed to the opposite side of the blank in the fourth cavity. The fourth main die is used for cold heading the blank cold-headed by the third main die and forming a positioning recess on the opposite side of the blank.

[0010] And a fifth main die has a fifth cavity. Above the fifth cavity, there is a fifth punch rod, which is opposed to the positioning recess of the blank in the fifth cavity. The bottom of the fifth cavity has a protrusion corresponding to the slot at the tail end of the piston, and the bottom end of the fifth punch rod corresponds to the inner hole at the front end of the piston. The bottom diameter of the fifth punch rod < the bottom diameter of the fourth punch rod.

[0011] In this solution, after the blank is cold-headed and shaped successively through the first main die and the second main die, the defects such as tiny hollows and cracks existing inside the blank are eliminated, making the internal structure of the blank become uniform and compact. Then, it is leveled by the third main die to further improve the internal structure of the blank and make it ready for positioning. Next, the fourth main die is used to cold head a positioning recess so that the fifth main die can form an inner hole on it. Finally, the fifth main die forms the inner hole and the slot of the blank at one time, thus effectively reducing the forming process of the piston, improving the production efficiency, and achieving the advantage of high forming precision of the piston through five times of cold heading forming.

[0012] Among them, in the actual production process, since the blanks are generally cut from wire rods, the surface roughness of both ends of the cut blanks is completely different. Specifically, when the wire rod is cut, slight bending deformation will occur on the side close to the main body of the wire rod. Therefore, one end of the blank has high surface finish and the other side has low surface finish. This is usually ignored and not noticed, but this is the key to whether the slot at the bottom of the piston can be formed. For example, when cold heading in the fifth main die, if the side with poor surface finish of the blank faces down, it will cause defects in the formed slot of the piston. In fact, this is also one of the key points for the successful cold heading forming of the piston of the present invention; the present invention cleverly usually cold heads the blank twice in positive and negative directions and then translates it to the fifth main die, making the side with better surface finish face down to form the slot, so as to achieve no defects in the formed slot.

[0013] Furthermore, a material cutting assembly is arranged on the side of the first main die. The material cutting assembly includes a material cutting seat for positioning the wire rod and scissors for cutting the material.

[0014] Furthermore, a first ejector rod for ejecting the blank inside it is arranged below the first cavity, a second ejector rod for ejecting the blank inside it is arranged below the second cavity, a third ejector rod for ejecting the blank inside it is arranged below the third cavity, a fourth ejector rod for ejecting the blank inside it is arranged below the fourth cavity, and a fifth ejector rod for ejecting the piston inside it is arranged below the fifth cavity.

[0015] Further, the bottom end of the first cavity has a first chamfering portion, and the bottom end of the second cavity has a second chamfering portion.

[0016] Further, the diameter of the first cavity < the diameter of the second cavity, the diameter of the second cavity < the diameter of the third cavity, the diameter of the third cavity < the diameter of the fourth cavity, and the diameter of the fourth cavity < the diameter of the fifth cavity.

[0017] The present invention also provides a multi-station cold heading and forging forming process for a caliper piston, comprising the following steps:

[0018] S1: Prepare materials, provide a wire blank for forming a piston, and set the two end faces of the blank as the front face and the back face respectively, and the surface roughness of the front face of the blank ≤ the surface roughness of the back face of the blank.

[0019] S2: Place the blank in step S1 into the second cavity of the first main die, push the first punch rod into the first main die, perform cold heading and shaping on the blank, and eject it by the first ejector rod to obtain a first finished blank with a rounded corner at the reverse end.

[0020] S3: Place the first finished blank in step S2 into the second cavity of the second main die, push the second punch rod into the second main die, perform cold heading and shaping on the first finished blank, and eject it by the second ejector rod to obtain a second finished blank with a rounded corner at the front end.

[0021] S4: Place the second finished blank in step S3 into the third cavity of the third main die, oppose the front face of the second finished blank to the third punch rod, push the third punch rod into the third main die, perform cold heading and shaping on the second finished blank, and eject it by the third ejector rod to obtain a third finished blank.

[0022] S5: Place the third finished blank in step S4 into the fourth cavity of the fourth main die, push the fourth punch rod into the fourth main die, perform cold heading and shaping on the third finished blank, and eject it by the third ejector rod to obtain a fourth finished blank with a positioning recess at the reverse side.

[0023] S6: Place the fourth finished blank in step S5 into the fifth cavity of the fifth main die, oppose the reverse side of the fourth finished blank to the fifth punch rod, push the fifth punch rod into the fifth main die, perform cold heading and shaping on the fourth finished blank, and eject it by the fourth ejector rod to obtain a piston with an inner hole at one end and a card slot at the other end.

[0024] The beneficial effects of the present invention are as follows: The caliper piston multi-station cold heading forging module and the cold heading forging process of the present invention eliminate defects such as tiny hollows and cracks existing inside the blank by cold heading and shaping the blank through the first main die and the second main die in sequence, making the internal structure of the blank uniform and compact. Then, it is leveled by the third main die to further improve the internal structure of the blank and prepare it for positioning. Next, a positioning recess is cold headed by the fourth main die so that the fifth main die can form an inner hole for it. Finally, the inner hole and the card slot of the blank are formed at one time by the fifth main die, thus effectively reducing the forming process of the piston, improving production efficiency, and achieving the advantages of high forming accuracy of the piston through five times of cold heading forming, and ensuring that there are no defects in the card slot formed at the bottom of the piston, improving the quality of the piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the drawings and embodiments.

[0026] Figure 1 is a cross-sectional schematic view of the caliper piston multi-station cold heading forging module of the present invention;

[0027] Figure 2 is a top view schematic diagram of the caliper piston multi-station cold heading forging module of the present invention;

[0028] Figure 3 is a schematic diagram of the fifth main die in the caliper piston multi-station cold heading forging module of the present invention;

[0029] Figure 4 is a schematic diagram of the cold heading process flow of the caliper piston of the present invention;

[0030] Figure 5 is a schematic diagram of the caliper piston in the present invention.

[0031] In the figure: 1. First main die, 11. First cavity, 11-1. First chamfering part, 12. First punch rod, 13. First ejector rod;

[0032] 2. Second main die, 21. Second cavity, 21-1. Second chamfering part, 22. Second punch rod, 23. Second ejector rod;

[0033] 3. Third main die, 31. Third cavity, 32. Third punch rod, 33. Third ejector rod;

[0034] 4. Fourth main die, 41. Fourth cavity, 42. Fourth punch rod, 43. Fourth ejector rod;

[0035] 5. Fifth main die, 51. Fifth cavity, 51-1. Protrusion, 52. Fifth punch rod, 53. Fifth ejector rod;

[0036] 6. Stock cutting assembly, 61. Stock cutting seat, 62. Scissors;

[0037] 7. Blanks, 71. First finished blank, 72. Second finished blank, 73. Third finished blank, 74. Fourth finished blank, 74-1. Positioning recess, 701. Front side, 702. Reverse side;

[0038] 8. Piston, 801. Inner hole, 802. Card slot. Detailed implementation mode

[0039] Now, the present invention will be further described in detail with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner. Therefore, they only show the components related to the present invention, and directions and references (such as up, down, left, right, etc.) can only be used to assist in the description of the features in the drawings. Therefore, the following specific implementation modes are not adopted in a restrictive sense, and the scope of the claimed subject matter is only defined by the appended claims and their equivalent forms.

[0040] Embodiment 1

[0041] As Figures 1-5 shown, a multi-station cold heading forging module for a caliper piston is used to cold head a blank 7 into a piston 8. The cold heading forging module includes:

[0042] The first main die 1 has a first cavity 11. Above the first cavity 11, there is a first punch 12, and the first punch 12 is opposed to the front side 701 of the blank 7 in the first cavity 11;

[0043] The second main die 2 has a second cavity 21. Above the second cavity 21, there is a second punch 22. The second main die 2 is used to cold head the blank 7 cold headed by the first main die 1, and the second punch 22 is opposed to the reverse side 702 of the blank 7 in the second cavity 21;

[0044] The third main die 3 has a third cavity 31. Above the third cavity 31, there is a third punch 32. The third main die 3 is used to cold head the blank 7 cold headed by the second main die 2, and the third punch 32 is opposed to the front side 701 of the blank 7 in the third cavity 31;

[0045] The fourth main die 4 has a fourth cavity 41. Above the fourth cavity 41, there is a fourth punch 42. The fourth punch 42 is opposed to the reverse side 702 of the blank 7 in the fourth cavity 41. The fourth main die 4 is used to cold head the blank 7 cold headed by the third main die 3 and form a positioning recess 74-1 on the reverse side 702 of the blank 7;

[0046] And a fifth main die 5, having a fifth cavity 51, above which there is a fifth punch 52. The fifth punch 52 is opposed to the positioning recess 74-1 of the blank 7 in the fifth cavity 51. The bottom of the fifth cavity 51 has a protrusion 51-1 corresponding to the tail-end card slot 802 of the piston 8. The bottom end of the fifth punch 52 corresponds to the inner hole 801 at the front end of the piston 8. The bottom diameter of the fifth punch 52 < the bottom diameter of the fourth punch 42; the inner hole 801 of the piston 8 is cold-heading formed at the bottom end of the second punch 22, and the card slot 802 of the piston 8 is formed by the protrusion 51-1 of the fifth cavity 51.

[0047] A cutting component 6 is arranged on the side of the first main die 1. The cutting component 6 includes a cutting seat 61 for positioning the wire rod and scissors 62 for cutting the material.

[0048] Below the first cavity 11, there is a first ejector rod 13 for ejecting the blank 7 therein. Below the second cavity 21, there is a second ejector rod 23 for ejecting the blank 7 therein. Below the third cavity 31, there is a third ejector rod 33 for ejecting the blank 7 therein. Below the fourth cavity 41, there is a fourth ejector rod 43 for ejecting the blank 7 therein. Below the fifth cavity 51, there is a fifth ejector rod 53 for ejecting the piston 8 therein.

[0049] The bottom end of the first cavity 11 has a first chamfer 11-1, and the bottom end of the second cavity 21 has a second chamfer 21-1; thus, the internal defects of the initial blank 7 can be better eliminated; the first chamfer 11-1 can specifically be a first chamfer 11-1 with a rounded corner, and the second chamfer 21-1 can specifically be a second chamfer 21-1 with a rounded corner.

[0050] The diameter of the first cavity 11 < the diameter of the second cavity 21, the diameter of the second cavity 21 < the diameter of the third cavity 31, the diameter of the third cavity 31 < the diameter of the fourth cavity 41, the diameter of the fourth cavity 41 < the diameter of the fifth cavity 51; thus, the blank 7 is cold-heading formed in a gradually thickening manner until it is the same as the diameter of the piston 8.

[0051] In this embodiment, after the blank 7 is cold-heading shaped successively through the first main die 1 and the second main die 2, the minute hollow and cracks and other defects existing inside the blank 7 are eliminated, making the internal structure of the blank 7 become uniform and compact. Then, it is leveled through the third main die 3, and the internal structure of the blank 7 is improved again to make it ready for positioning. Then, the positioning recess 74-1 is cold-heading formed through the fourth main die 4 so that the fifth main die 5 can form the inner hole 801 for it. Finally, the inner hole 801 and the card slot 802 of the blank 7 are formed at one time by the fifth main die 5, thus effectively reducing the forming process of the piston 8, improving the production efficiency, and achieving the advantage of high forming accuracy of the piston 8 through five times of cold-heading forming.

[0052] Among them, in the actual production process, since the blank 7 is generally cut from wire, the surface roughness of both ends of the cut blank 7 is completely different. Specifically, when the wire is cut, a slight bending deformation will occur on the side close to the main body of the wire. Therefore, one end of the blank 7 has a high finish and the other side has a low finish. This is usually overlooked and not noticed, but this is the key to whether the bottom card slot 802 of the piston 8 can be formed. For example, when cold heading the fifth main die 5, if the side with a poor finish of the blank 7 faces down, it will cause defects in the formed card slot 802 of the piston 8. In fact, this is also one of the key points for the successful cold heading forming of the piston 8 of the present invention; the present invention usually and ingeniously performs two forward and reverse cold headings on the blank 7 and then translates it to the fifth main die 5 so that the side with a better finish faces down to form the card slot 802, thereby realizing that the formed card slot 802 has no defects.

[0053] This embodiment also provides a multi-station cold heading and forging forming process for a caliper piston, including the following steps:

[0054] S1: Prepare materials, provide a wire blank 7 for forming the piston 8, and set the two end faces of the blank 7 as the front face 701 and the back face 702 respectively. The surface roughness of the front face 701 of the blank 7 ≤ the surface roughness of the back face 702 of the blank 7; specifically, a blank 7 with a predetermined length can be sheared by the cutting component 6. The wire passes through the cutting seat 61 and protrudes a certain distance above the upper surface of the cutting seat 61, and this distance is equal to the predetermined length of the blank 7. Then, the scissors 62 are rotated to cut off the part of the wire protruding from the cutting seat 61, thereby obtaining the blank 7.

[0055] S2: Translate and place the blank 7 in step S1 into the second cavity 21 of the first main die 1. The first punch 12 is advanced into the first main die 1 to cold heading and shape the blank 7, and it is ejected by the first ejector rod 13 to obtain the first finished blank 71 with a rounded corner at the end of the back face 702.

[0056] S3: Translate and flip the first finished blank 71 in step S2 and place it into the second cavity 21 of the second main die 2. The second punch 22 is advanced into the second main die 2 to cold heading and shape the first finished blank 71, and it is ejected by the second ejector rod 23 to obtain the second finished blank 72 with a rounded corner at the end of the front face 701.

[0057] S4: Translate and flip the second finished blank 72 in step S3 and place it into the third cavity 31 of the third main die 3. The front face 701 of the second finished blank 72 is opposed to the third punch 32. The third punch 32 is advanced into the third main die 3 to cold heading and shape the second finished blank 72, and it is ejected by the third ejector rod 33 to obtain the third finished blank 73.

[0058] S5: Translate and turn the third finished blank 73 in step S4 and place it into the fourth cavity 41 of the fourth main die 4. The fourth punch rod 42 is advanced into the fourth main die 4 to perform cold heading and shaping on the third finished blank 73, and it is ejected by the third ejector rod 33 to obtain a fourth finished blank 74 with a positioning recess 74-1 on the reverse side 702.

[0059] S6: Translate and place the fourth finished blank 74 in step S5 into the fifth cavity 51 of the fifth main die 5. The reverse side 702 of the fourth finished blank 74 faces the fifth punch rod 52. The fifth punch rod 52 is advanced into the fifth main die 5 to perform cold heading and shaping on the fourth finished blank 74, and it is ejected by the fourth ejector rod 43 to obtain a piston 8 with an inner hole 801 at one end and a clamping groove 802 at the other end.

[0060] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A multi-station cold heading forging module for a caliper piston, which is used to cold head a blank (7) into a piston (8). The surface finish of the front surface (701) of the blank (7) is higher than that of the back surface (702). It is characterized in that: The cold heading forging module includes: A first main die (1) having a first cavity (11). Above the first cavity (11), there is a first punch rod (12), and the first punch rod (12) is opposed to the front surface (701) of the blank (7) in the first cavity (11). A second main die (2) having a second cavity (21). Above the second cavity (21), there is a second punch rod (22). The second main die (2) is used for cold heading the blank (7) cold-headed by the first main die (1), and the second punch rod (22) is opposed to the reverse surface (702) of the blank (7) in the second cavity (21). A third main die (3) having a third cavity (31). Above the third cavity (31), there is a third punch rod (32). The third main die (3) is used for cold heading the blank (7) cold-headed by the second main die (2), and the third punch rod (32) is opposed to the front surface (701) of the blank (7) in the third cavity (31). A fourth main die (4) having a fourth cavity (41). Above the fourth cavity (41), there is a fourth punch rod (42). The fourth punch rod (42) is opposed to the reverse surface (702) of the blank (7) in the fourth cavity (41). The fourth main die (4) is used for cold heading the blank (7) cold-headed by the third main die (3) and forming a positioning recess (74-1) on the reverse surface (702) of the blank (7). And a fifth main die (5) having a fifth cavity (51). Above the fifth cavity (51), there is a fifth punch rod (52). The fifth punch rod (52) is opposed to the positioning recess (74-1) of the blank (7) in the fifth cavity (51). The bottom of the fifth cavity (51) has a protrusion (51-1) corresponding to the tail-end card slot (802) of the piston (8), and the bottom end of the fifth punch rod (52) corresponds to the front-end inner hole (801) of the piston (8). The bottom diameter of the fifth punch rod (52) < the bottom diameter of the fourth punch rod (42). After the blank (7) is cold-headed twice in the positive and reverse directions, it is translated to the fifth main die (5). The bottom end of the first cavity (11) has a first chamfered portion (11-1), and the bottom end of the second cavity (21) has a second chamfered portion (21-1). A cutting component (6) is arranged on the side of the first main die (1). The cutting component (6) includes a cutting seat (61) for positioning the wire rod and scissors (62) for cutting the material.

2. The multi-station cold heading forging module of a caliper piston according to claim 1, characterized in that: Below the first cavity (11), there is a first ejector rod (13) for ejecting the blank (7) therein. Below the second cavity (21), there is a second ejector rod (23) for ejecting the blank (7) therein. Below the third cavity (31), there is a third ejector rod (33) for ejecting the blank (7) therein. Below the fourth cavity (41), there is a fourth ejector rod (43) for ejecting the blank (7) therein. Below the fifth cavity (51), there is a fifth ejector rod (53) for ejecting the piston (8) therein.

3. The multi-station cold heading forging module of a caliper piston according to claim 1, characterized in that: The diameter of the first cavity (11) < the diameter of the second cavity (21), the diameter of the second cavity (21) < the diameter of the third cavity (31), the diameter of the third cavity (31) < the diameter of the fourth cavity (41), and the diameter of the fourth cavity (41) < the diameter of the fifth cavity (51).

4. A multi-station cold heading and forging forming process for a caliper piston, which uses the multi-station cold heading and forging module for the caliper piston as described in claim 2, and is characterized in that: It includes the following steps: S1: Prepare materials. Provide a wire blank (7) for forming a piston (8), and set the two end faces of the blank (7) as the front face (701) and the back face (702) respectively. The surface roughness of the front face (701) of the blank (7) < the surface roughness of the back face (702) of the blank (7); S2: Place the blank (7) in step S1 into the first cavity (11) of the first main die (1). The first punch rod (12) is advanced into the first main die (1) to perform cold heading and shaping on the blank (7), and it is ejected by the first ejector rod (13) to obtain a first finished blank (71) with a chamfered end at the back face (702); S3: Place the first finished blank (71) in step S2 into the second cavity (21) of the second main die (2). The second punch rod (22) is advanced into the second main die (2) to perform cold heading and shaping on the first finished blank (71), and it is ejected by the second ejector rod (23) to obtain a second finished blank (72) with a chamfered end at the front face (701); S4: Place the second finished blank (72) in step S3 into the third cavity (31) of the third main die (3). The front face (701) of the second finished blank (72) is opposed to the third punch rod (32). The third punch rod (32) is advanced into the third main die (3) to perform cold heading and shaping on the second finished blank (72), and it is ejected by the third ejector rod (33) to obtain a third finished blank (73); S5: Place the third finished blank (73) in step S4 into the fourth cavity (41) of the fourth main die (4). The fourth punch rod (42) is advanced into the fourth main die (4) to perform cold heading and shaping on the third finished blank (73), and it is ejected by the fourth ejector rod (43) to obtain a fourth finished blank (74) with a positioning recess (74-1) at the back face (702); S6: Place the fourth finished blank (74) in step S5 into the fifth cavity (51) of the fifth main die (5). The back face (702) of the fourth finished blank (74) is opposed to the fifth punch rod (52). The fifth punch rod (52) is advanced into the fifth main die (5) to perform cold heading and shaping on the fourth finished blank (74), and it is ejected by the fifth ejector rod (53) to obtain a piston (8) with an inner hole (801) at one end and a clamping groove (802) at the other end.

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