Method for forging a curved circular shaft with a distance ratio between the fetal membrane and the bending point and the two end ends greater than 2

Abstract

The invention belongs to the field of free forging, and relates to a method for forging a curved round shaft with a ratio of the distance between a bending point and two end caps being greater than 2. The curved fetal membrane is used to forge a curved round shaft with a ratio of the distance between a bending point and two end caps being greater than 2, and the curved round shaft comprises a curved portion and a positioning portion with a step; the curved fetal membrane comprises: an upper curved fetal membrane and a lower curved fetal membrane.

Description

Technical Field

[0001] The invention belongs to the field of free forging and relates to a forging method for a curved round shaft with a distance ratio between a fetal membrane and a bending point and two end heads being greater than 2. Background Art

[0002] In order to reduce the consumption cost of forming pipe fittings, a rough type is designed according to the shape of the forging. The rough type is a bent circular shaft with steps, and according to the bending point of the die forging, the distance between the rough type bending point and the two end heads is more than 2 times. When bending with traditional bending membranes, if the bending angle is guaranteed, there will be pressure damage at the bending point of the rough type and the cross section of the circular shaft will be deformed; if the circularity of the rough type is guaranteed, the bending angle cannot meet the requirements. In this regard, a membrane is invented that can ensure that the cross section of the rough type circular shaft does not deform and can ensure the bending position and angle. Summary of the invention

[0003] The technical problems to be solved by the present invention are: (1) rough design; (2) design of curved fetal membrane.

[0004] The technical solution of the present invention is:

[0005] A curved fetal membrane is used for forging a curved circular shaft with a distance ratio between a bending point and two end ends greater than 2, the curved circular shaft comprising a curved portion and a positioning portion with a step; the curved fetal membrane comprises: an upper curved fetal membrane and a lower curved fetal membrane;

[0006] The parting surface of the upper curved fetal membrane is convex downward, and the parting surface of the lower curved fetal membrane is concave downward, and the most convex point of the upper curved fetal membrane corresponds to the most concave point of the lower curved fetal membrane; the mold cavity of the lower curved fetal membrane includes a positioning cavity and a bending cavity for forming a curved portion; the positioning cavity is used to accommodate the positioning portion, and a groove is provided on the positioning cavity. The space of the groove is the area through which the step rotates during the bending of the circular shaft, and the two side surfaces of the groove serve as the front and rear positioning surfaces of the step bending respectively; the step of the unbent circular shaft is tangent to the front positioning surface initially, and the step of the bent circular shaft is tangent to the rear positioning surface after molding; the mold cavity of the upper curved fetal membrane is used to accommodate the curved portion.

[0007] The calculation formula of the distance L of the bending support point of the lower bending die is: L = 4 (l1 + l2) / 5;

[0008] l1 and l2 are the distances from the bending point of the curved circular axis to the two end caps.

[0009] The sum of the included angles of the front and rear positioning surfaces and the bending angle of the curved circular axis is equal to 180 degrees.

[0010] The radius of the curved circle is larger than the cavity radius of the upper curved fetal membrane and smaller than the cavity radius of the lower curved fetal membrane.

[0011] There is a gap between the upper curved fetal membrane and the step of the curved circumference in the cavity.

[0012] A method for forging a curved round shaft with a distance ratio between a bending point and two end ends greater than 2, comprising:

[0013] The bar material is partially upset in the upset membrane to form a blank with a step on the upper part;

[0014] placing the blank formed with a step in the lower curved fetal membrane of the curved fetal membrane, with one side of the step in contact with the front positioning surface;

[0015] The upper curved membrane is moved downward, the blank is gradually bent, the step rotates with the bending, and gradually moves away from the front positioning surface until the other side of the step contacts the rear positioning surface; the upper curved membrane continues to move downward, the upper and lower curved membranes are closed, and finally bent into shape.

[0016] The material used for the bar is LY12.

[0017] The material of the curved fetal membrane is 5CrNiMo.

[0018] The beneficial effect of the present invention is that through the design of the new curved fetal membrane, the rough shape size required for die forging is achieved, which avoids the situation where the rough shape bending angle and circular shaft cross-section cannot be guaranteed at the same time when using ordinary curved fetal membrane to produce the rough shape, improves the accuracy of the rough shape size, and reduces the die forging consumption cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the wild type.

[0020] Figure 2 Schematic diagram of traditional curved fetal membrane.

[0021] Figure 3 It is a schematic diagram of the curved fetal membrane of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below through specific implementation examples:

[0023] The present invention relates to a forging method for a curved circular shaft with a step and a distance ratio between a bending point and two end heads greater than 2 times, comprising the following steps: Step 1: designing a rough shape according to the appearance characteristics of a die forging, the rough shape being designed as a curved circular shaft with a step, the distance between the bending point and the two end heads of the curved circular shaft being l1 and l2 respectively, and l2 / l1>2, and the entire cross section being a circle.

[0024] Step 2: Design the fetal membrane according to the rough shape and bending angle, the distance between the bending support points is L, the semicircular sizes of the upper and lower cavities of the bending die are R1 and R2 respectively, the front and rear positioning points of the bending are A and B respectively, and L=4(l1+l2) / 5, R1<r<R2; Step 3: The bar material is locally upset in the upsetting fetal membrane to form a step; Step 4: The blank with the step is then bent in the bending fetal membrane. Through the design of the new bending fetal membrane, the rough size required for die forging is achieved, which avoids the situation that the rough bending angle and the circular shaft cross-section cannot be guaranteed at the same time when using ordinary bending fetal membranes to produce rough shapes, improves the accuracy of the rough size, and reduces the die forging consumption cost.

[0025] A die forging with a bending point and two end heads having a distance ratio greater than 2 times and being a circle. In order to reduce die forging consumption, this rough shape is designed and a bending membrane is required for bending. The common bending membrane is designed, and the internal structure size of the common bending membrane cavity is consistent with the rough shape size. However, this bending membrane cannot bend the blank according to the shape inside the membrane cavity, especially for round shaft forgings. The bending angle and the cross section of the round shaft forgings with a difference in the distance between the bending point and the two end heads cannot be guaranteed at the same time. Therefore, the design scheme of the present invention is proposed.

[0026] Step 1: Design the rough type according to the shape characteristics of the die forging. The rough type is designed as a curved circular shaft with steps. The distances between the bending point and the two ends of the curved circular shaft are l1 and l2 respectively, and l2 / l1>2. The entire cross section is circular (the rough type diagram is as follows Figure 1 shown).

[0027] Step 2: Design a curved fetal membrane 1 according to the rough shape and bending angle. The rough shape is a round axis, the bending point is asymmetrical and close to one end, and the normal fetal membrane (such as Figure 2 The design shown in the figure cannot make the blank bend according to the shape of the bending membrane cavity, especially the circular axis section and the bending angle cannot be guaranteed at the same time. For this reason, a new bending membrane is invented, the bending support point distance is L, the upper and lower semicircular dimensions of the bending die cavity are R1 and R2 respectively, the front and rear positioning points of the bending are A and B respectively, and L = 4 (l1 + l2) / 5, R1 < r < R2, (the new bending membrane is as shown in the figure Figure 3 The new curved fetal membrane comprises an upper curved fetal membrane 1 and a lower curved fetal membrane 2, the parting surface of the upper curved fetal membrane 1 is convex downward, the parting surface of the lower curved fetal membrane 2 is concave downward, and the most convex point of the upper curved fetal membrane 1 corresponds to the most concave point of the lower curved fetal membrane 2; the mold cavity 3 of the lower curved fetal membrane comprises a positioning cavity 31 and a bending cavity 32 for forming a curved portion; the positioning cavity 31 is used to accommodate the positioning portion, and a groove 33 is provided on the positioning cavity 31, the space of the groove 33 is the area through which the step rotates during the bending process of the circular shaft, and the two side surfaces of the groove 33 serve as the front and rear positioning surfaces of the step bending respectively; the step of the unbent circular shaft is tangent to the front positioning surface A at the beginning, and the step of the bent circular shaft is tangent to the rear positioning surface B after forming; the mold cavity of the upper curved fetal membrane is used to accommodate the curved portion.

[0028] Step 3: The bar is locally upset in the upset membrane to form a step.

[0029] Step 4: Place the blank with the step formed in the lower curved fetal membrane, and one side of the step is in contact with the A surface positioned before bending.

[0030] Step 5: Move the upper curved fetal membrane downward, and the blank will gradually bend.

[0031] Step 6: When the blank is bent to a certain angle, the other side of the rough blank step contacts the positioning B surface, and after the upper and lower bending dies are closed, it is finally bent into shape.

[0032] In step 1, the entire cross-section of the rough type is a curved circular axis with a circular shape. The distances between the bending point and the two end ends are l1 and l2 respectively, and l2 / l1>2; in step 2, L is associated with l1 and l2, and L=4(l1+l2) / 5, r is associated with R1 and R2, and R1<r<R2. The material used for the rough type is LY12, and the material used for the fetal membrane is: 5CrNiMo.

[0033] The specific plan is as follows:

[0034] The rough shape forged by the present invention has a rough shape section size and a bending angle that meet the design requirements, is formed in a forging die, and has small and evenly distributed burrs after forging.

[0035] The present invention adopts a curved fetal membrane with a bending support point distance related to the rough length, an increased semicircular size of the lower curved fetal membrane cavity, a reduced semicircular size of the upper curved fetal membrane cavity, and a designed curved fetal membrane with front and rear positioning for blank making. The rough shape is produced by using this fetal membrane, which maximizes the material utilization rate and ensures the rough shape size.

[0036] The rough forging with a circular cross section and asymmetrical bending points is made of LY12 material and is completed in one forging. The bending of the rough forging is very important. The cross-sectional size and bending angle of each part are related to the forming and defect control of the die forging. This rough forging adopts the invented bending membrane forging method.

[0037] Step 1: Design the rough size according to the shape and size of the die forging. The rough size is designed as a curved round shaft with steps.

[0038] Step 2: Select the bar specifications and length dimensions, and upset in the upset membrane.

[0039] Step 3: Place the blank with the step formed in the lower curved fetal membrane, and one side of the step is in contact with the front positioning surface of the curve.

[0040] Step 5: Move the upper curved fetal membrane downward, and the blank will gradually bend.

[0041] Step 6: When the blank is bent to a certain angle, the other side of the rough blank step contacts the positioning surface, and after the upper and lower bending dies are closed, it is finally bent into shape.

Claims

1. A curved tire mold, characterized in that: Used for forging a curved circular shaft with a distance ratio between a bending point and two end heads greater than 2, the curved circular shaft comprising a curved portion and a positioning portion with a step; The bending mold includes: An upper curved tire mold and a lower curved tire mold; the splitting surface of the upper curved tire mold is convex downward, the splitting surface of the lower curved tire mold is concave downward, and the most convex point of the upper curved tire mold corresponds to the most concave point of the lower curved tire mold; The cavity of the lower bending mold includes a positioning cavity and a bending cavity for forming a bending portion; the positioning cavity is used to accommodate the positioning portion, and a groove is provided on the positioning cavity. The space of the groove is the area through which the step rotates during the bending process of the circular shaft, and the two side surfaces of the groove serve as the front and rear positioning surfaces of the step bending respectively; Initially, the step of the unbent circular shaft is tangent to the front positioning surface, and the step of the bent circular shaft after forming is tangent to the rear positioning surface; The cavity of the upper bending mold is used to accommodate the bending part; the calculation formula of the bending support point distance L of the lower bending mold is: L = 4 (l1 + l2) / 5; l1 and l2 are the distances between the bending point of the bending shaft and the two ends respectively; the sum of the angles between the front and rear positioning surfaces and the bending angle of the bending shaft is equal to 180 degrees; the radius of the bending shaft is larger than the cavity radius of the upper bending mold and smaller than the cavity radius of the lower bending mold; Placing the blank formed with the step in the lower bending mold with one side of the step in contact with the front positioning surface; Move the upper bending mold downward, the blank gradually bends, and the step rotates as it bends, gradually moving away from the front positioning surface until the other side of the step contacts the rear positioning surface; The upper bending mold continues to move downward, and the upper and lower bending molds are closed, and finally the bending is formed to obtain a rough shape in which the cross section of the rough-shaped circular shaft is not deformed and the bending position and angle are guaranteed.

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