Parking arm manufacturing mold structure and manufacturing method

Abstract

The application relates to a parking arm manufacturing die structure and a manufacturing method, and the die structure comprises an extrusion die arranged between a fixed lower die base and a vertically movable upper die base, the extrusion die is provided with a to-be-extruded cavity and an extrusion working section which are connected in series and penetrate through the extrusion die; the extrusion die is arranged on the lower die base, the upper die base is connected with an upper extrusion die rod which can extend into the extrusion die; a material lifting rod which can extend into the extrusion die is arranged through the lower die base to extend to the to-be-extruded cavity for material bearing when being extruded, the material lifting rod is connected with a telescopic oil cylinder which drives the material lifting rod to vertically move to descend to the lower end of the extrusion working section and provide back pressure during the extrusion process; the extrusion die comprises two half dies which are split left and right, the two half dies are slidably arranged on the lower die base for feeding and discharging, and the to-be-extruded cavity and the extrusion working section are also respectively machined on the two half dies. The application can overcome the problems of uneven material discharging, uneven stress and bending which are prone to occur in conventional cold extrusion and affect the forming quality.

Description

Technical Field

[0001] This invention belongs to the technical field of metal extrusion forming tools, specifically relating to a parking arm manufacturing mold structure and manufacturing method. Background Technology

[0002] The parking mechanism is a safety device in automatic transmissions or new energy electric drive systems that prevents vehicles from coasting. It reliably and indefinitely parks the vehicle in a designated position, even on a slope, and is an indispensable key component of these systems. The parking mechanism is a complex kinematic mechanism, typically composed of three parts: ① parking gears and parking arms; ② parking shift adjustment device; ③ sliding mechanism. To achieve the parking design goals, the parking gears and parking arms are particularly important. Traditionally, the parking arms are forged and then the key working surfaces are milled using a machining center. However, this method often results in inconsistent surface contours and roughness that do not meet design requirements, leading to excessive parking arm engagement and disengagement forces, causing vibration and noise. To improve efficiency and ensure quality, some systems use cold extrusion to form the circumferential key working surfaces after forging the blank, such as... Figure 4 The parking arm shown is a uniform cross-section component with a thickness of approximately 11mm and a total length of approximately 100mm in the vertical direction. However, during the extrusion process, problems such as uneven material feeding, uneven extrusion force, extrusion bending deformation, and difficulty in material removal after extrusion occur, resulting in poor quality consistency. Further optimization and improvement are needed. Summary of the Invention

[0003] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a parking arm manufacturing mold structure and manufacturing method, so as to avoid the problem of unstable manufacturing quality of the current parking arm and achieve the effect of effectively improving the manufacturing efficiency and quality of the parking arm.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] The parking arm manufacturing mold structure includes an extrusion mold, which is located between a fixed lower mold base and an upper mold base that can move vertically to perform the extrusion action. The extrusion mold has a cavity to be pressed and an extrusion working section that are connected vertically and pass through the extrusion mold. The extrusion mold is located on the lower mold base, and an upper extrusion mold rod that can move with the upper mold base and extend into the extrusion mold is connected to the upper mold base. A push rod that can extend into the extrusion mold is provided through the lower mold base to extend to the cavity to be pressed for material support during extrusion. The push rod is connected to a telescopic cylinder that drives its vertical movement so that it descends to the lower end of the extrusion working section during the extrusion process and provides back pressure. The extrusion mold adopts a half mold structure, including two mold halves that are separated into left and right halves. The two mold halves can slide towards and away from each other on the lower mold base for material loading and unloading. The cavity to be pressed and the extrusion working section are also machined in half on the two mold halves so that the cavity to be pressed and the extrusion working section are formed when the two mold halves are closed towards each other.

[0006] To further improve the above technical solution, the two mold halves are respectively connected to a horizontal drive mechanism so as to realize the sliding actions of the two mold halves on the lower mold base in opposite directions and in opposite directions.

[0007] Furthermore, the horizontal drive mechanism is a telescopic cylinder.

[0008] Furthermore, a lower die washer is provided between the extrusion die and the lower die base. The lower die washer is fixed to the lower die. A recessed groove is provided on the upper surface of the lower die washer. The lower surfaces of the two die halves are respectively provided with raised slide rails that are adapted to the slide rails. The two die halves are placed on the lower die washer and can slide along the movement direction of the slide rails and the slide rails. The ejector rod passes through the lower die washer.

[0009] Furthermore, the upper surface contour shape of the top rod corresponds to the cross-section of the extrusion working section.

[0010] This invention also relates to a method for manufacturing a parking arm, which is based on the above-mentioned parking arm manufacturing mold structure and includes the following steps:

[0011] 1) Feeding: The ejector rod extends to the cavity to be pressed, and the two mold halves slide open in opposite directions, placing the blank on the upper surface of the ejector rod;

[0012] 2) Mold closing; the two mold halves slide and close together to form a cavity to be pressed and an extrusion working section, and the billet is located in the cavity to be pressed;

[0013] 3) Extrusion; The upper die presses down, driving the upper extrusion die rod to move downward so that its lower surface contacts the blank and applies pressure. The telescopic cylinder provides back pressure to the blank through the ejector rod. The back pressure is less than the pressure of the upper die pressing down. The upper extrusion die rod simultaneously pushes the blank and the ejector rod downward. The blank is pushed into the extrusion working section and is extruded into the working surfaces of each circumference. During the extrusion process, the ejector rod always provides back pressure to the blank.

[0014] 4) Holding pressure; After the upper extrusion die rod descends to the designed height, it stops pressing down and maintains that height, while the ejector rod continues to provide back pressure to the billet;

[0015] 5) Unloading: After the pressure holding time is met, the upper extrusion die rod moves upward and leaves the extrusion die. The ejector rod no longer provides back pressure to the billet but only serves as a bearing surface. The two halves of the die slide open in opposite directions and the extruded billet is removed.

[0016] Further, before step 1), the billet is forged, and the cross-section of the billet after forging corresponds to the cross-section of the extrusion section, but it still has a small amount of thickness allowance on one side compared to the extrusion section; the cross-section of the cavity to be pressed is larger than the cross-section of the billet after forging.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention has two outstanding advantages: First, it facilitates loading and unloading. Because the critical surfaces of the billet typically have 0.20~0.25mm of excess material on one side, it cannot be directly placed into the conventional extrusion section. Even with the addition of a guide ramp at the opening of a conventional structure, the non-symmetrical working surface of the parking arm still leads to uneven material feeding, affecting the cold forming quality. In contrast, the opening cavity of this invention effectively avoids the problem of difficult material feeding, and is stably supported by the ejector rod. The two mold halves slide towards each other to form the cavity, where the billet is placed for pressing. After extrusion, the two mold halves slide back to each other to open and remove the extruded billet, which is very convenient and easy.

[0019] Secondly, by combining the telescopic hydraulic cylinder with the back pressure provided to the billet through the top rod during the extrusion process, a precision cold forming method with increased back pressure is achieved. This method can overcome problems such as uneven stress and bending deformation of the billet that occur during conventional cold extrusion (with an open structure at the lower end). The formed working surfaces in each circumferential direction can stably meet the design requirements of the parking mechanism, eliminating the need for material removal. In particular, the forming consistency of the bottom surface supported by the top rod is also very high. In subsequent machining (non-extrusion forming working surface) processes, the bottom surface and any one of the circumferential working surfaces can be used as references. The two reference surfaces can ensure the consistency of the processing references in subsequent processes, thereby ensuring the manufacturing quality of the parking arm throughout the entire manufacturing process. Attached Figure Description

[0020] Figure 1 A schematic diagram of the parking arm manufacturing mold structure for an embodiment (top view, upper mold base and upper extrusion mold rod are hidden).

[0021] Figure 2 for Figure 1 AA cross-sectional view (showing the upper die base and upper extrusion die rod);

[0022] Figure 3 for Figure 2 A separate schematic diagram of the extrusion die (enlarged);

[0023] Figure 4 This is a cross-sectional schematic diagram of the parking arm mentioned in the background art;

[0024] The components include: extrusion die 1, two-part die 11, slide rail 12, telescopic cylinder 13, push block 14, pressing cavity 16, extrusion working section 17, lower die base 2, lower die washer 21, upper die base 3, upper extrusion die rod 31, ejector rod 4, telescopic oil cylinder 41, and billet 5. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] See Figure 1-3 The specific embodiment of the parking arm manufacturing mold structure includes an extrusion mold 1, which is disposed between a fixed lower mold base 2 and an upper mold base 3 that can move vertically to perform the extrusion action. The extrusion mold 1 has a cavity 16 to be pressed and an extrusion working section 17 that are vertically connected and pass through the extrusion mold 1. The extrusion mold 1 is disposed on the lower mold base 2, and an upper extrusion mold rod 31 is connected to the upper mold base 3 and can move with the upper mold base 3 to extend into the extrusion mold 1 (the cavity 16 to be pressed and the extrusion working section 17). A rod 31 that can extend into the cavity 16 to be pressed and the extrusion working section 17 is disposed through the lower mold base 2. The ejector rod 4 (within the extrusion section 17) extends to the pressing cavity 16 to support the material during extrusion. The ejector rod 4 is connected to a telescopic cylinder 41 that drives its vertical movement, so that it descends to the lower end of the extrusion section 17 during the extrusion process and continuously provides back pressure. The extrusion die 1 adopts a half-die structure, including two halves of the die 11 that are separated into left and right halves. The two halves of the die 11 can slide towards and away from each other on the lower die base 2 for loading and unloading. The pressing cavity 16 and the extrusion section 17 are also machined in half on the two halves of the die 11 so that the pressing cavity 16 and the extrusion section 17 are formed when the two halves of the die 11 are closed towards each other. It is understood that since the machining accuracy and roughness requirements of the effective extrusion section are very high, it is not necessary to make it too long. Therefore, the lower end of the extrusion section 17 in this embodiment is also set to be circumferentially enlarged and recessed, and its cross-section can correspond to the pressing cavity 16.

[0027] The parking arm manufacturing mold structure of this embodiment is used in accordance with the following steps:

[0028] 1) Feeding: The ejector rod 4 extends to the cavity 16 to be pressed, and the two mold halves 11 slide open in opposite directions, placing the blank 5 on the upper surface of the ejector rod 4;

[0029] 2) Mold closing; the two mold halves 11 slide and close together to form a cavity to be pressed 16 and an extrusion working section 17, and the billet 5 is located in the cavity to be pressed 16 to be pressed;

[0030] 3) Extrusion; The upper die holder 3 presses down, driving the upper extrusion die rod 31 to move downward so that its lower surface contacts the blank 5 and applies pressure. The telescopic cylinder 41 provides back pressure to the blank 5 through the ejector rod 4. The back pressure is less than the pressure of the upper die holder 3 pressing down. The upper extrusion die rod 31 simultaneously pushes the blank 5 and the ejector rod 4 downward. The blank 5 is pushed into the extrusion working section 17 and is extruded into working surfaces in all directions. During the extrusion process, the ejector rod 4 always provides back pressure to the blank 5.

[0031] 4) Holding pressure; After the upper extrusion die rod 31 descends to the designed height, it stops pressing down and remains at that height, while the ejector rod 4 continues to provide back pressure to the billet 5;

[0032] 5) Unloading: After the pressure holding time is met, the upper extrusion die rod 31 moves upward and leaves the extrusion die 1. The ejector rod 4 no longer provides back pressure to the blank 5 but only serves as a bearing surface. The two halves of the die 11 slide open in opposite directions and the extruded blank 5 is removed.

[0033] Of course, before step 1), the billet 5 is forged. After forging, the cross-section of the billet 5 corresponds to the cross-section of the extrusion working section 17, but it still has a small amount of thickness allowance on one side compared to the extrusion working section 17. The cross-section of the cavity to be pressed 16 is larger than the cross-section of the billet 5 after forging, and is also larger than the cross-section of the extrusion working section 17. The cavity to be pressed 16 and the extrusion working section 17 are smoothly and continuously transitioned by a slope.

[0034] As can be seen, the parking arm manufacturing mold structure of this embodiment has two outstanding advantages: First, it is convenient for loading and unloading materials. Because the key surface of the blank 5 usually has 0.20~0.25mm of excess material on one side, it cannot be directly put into the extrusion working section 17 of the conventional structure. Even if an inlet ramp is added to the conventional structure, the working surface of the parking arm is not symmetrical, which will still lead to uneven material feeding and affect the cold forming quality. However, the opening of the pressing cavity 16 in this embodiment can effectively avoid the problem of difficult material feeding, and it is stably supported by the ejector rod 4. After the two mold halves 11 slide towards each other and close, the pressing cavity 16 is formed, and the blank 5 is located in the pressing cavity 16 to be pressed. After extrusion, the two mold halves 11 slide back and forth to open and remove the extruded blank 5, which is very convenient and easy.

[0035] Secondly, by combining the telescopic cylinder 41 with the back pressure provided to the billet 5 through the top rod 4 during the extrusion process, a precision cold forming preparation method with increased back pressure is achieved. This can overcome the problems of uneven stress and bending deformation of the billet 5 that occur in conventional cold extrusion (with an open structure at the lower end). The formed working surfaces in each circumferential direction can stably meet the design requirements of the parking mechanism, eliminating the need for material removal. In particular, the forming consistency of the bottom surface supported by the top rod 4 is also very high. In the subsequent machining process (non-extrusion forming working surface), the bottom surface and any one of the circumferential working surfaces can be used as references. The two reference surfaces can ensure the consistency of the processing references in the subsequent process, thereby ensuring the manufacturing quality of the parking arm in the entire manufacturing process.

[0036] The two mold halves 11 are respectively connected to a horizontal drive mechanism to enable the two mold halves 11 to slide towards and away from each other on the lower mold base 2. The horizontal drive mechanism is a telescopic cylinder 13. In implementation, the telescopic cylinder 13 can be connected to the two mold halves 11 by a push block 14 that is adapted to the shape of the two mold halves 11.

[0037] In this way, in addition to being able to manually open the two-part mold 11 and close the mold (after closing, it can be kept in the closed position by other clamps for extrusion), a horizontal drive mechanism is adopted, which makes it more convenient to use, has a higher degree of automation, improves efficiency, and also ensures safer use.

[0038] The extrusion die 1 is provided with a lower die washer 21 between it and the lower die base 2. The lower die washer 21 is fixed to the lower die. The upper surface of the lower die washer 21 is provided with a recessed groove. The lower surfaces of the two die halves 11 are respectively provided with raised slide rails 12 that are adapted to the slide rails. The two die halves 11 are placed on the lower die washer 21 and can slide along the movement direction of the slide rails 12 and the slide rails. The ejector rod 4 passes through the lower die washer 21.

[0039] In this way, sliding contact is provided by the lower die washer 21. Since sliding parts are also vulnerable parts, the lower die washer 21 can be more easily maintained and repaired, saving costs.

[0040] The upper surface contour of the ejector rod 4 corresponds to the cross-section of the extrusion section 17. The lower surface contour of the upper extrusion die rod 31 also corresponds to the cross-section of the extrusion section 17. This facilitates extrusion and better ensures the forming effect of the bottom plane of the blank 5.

[0041] This invention also provides a method for manufacturing a parking arm. This method is based on the above-mentioned parking arm manufacturing mold structure, and the manufacturing steps are further described below:

[0042] 1) First, the bar stock is forged, usually by heating and then forging, to obtain the billet 5 to be extruded. After forging, the cross-section of the billet 5 has a small thickness allowance on one side compared to the cross-section of the extrusion working section 17, usually 0.20~0.25mm. The cross-section of the cavity 16 to be pressed is larger than the cross-section of the billet 5 after forging, so as to facilitate subsequent feeding.

[0043] 2) Remove oxide scale from the surface of billet 5 and lubricate the billet;

[0044] 3) Discharge; The ejector rod 4 extends to the cavity to be pressed 16, and the two mold halves 11 slide open in opposite directions under the drive of the telescopic cylinder 13, placing the room temperature blank 5 on the upper surface of the ejector rod 4.

[0045] 4) Mold closing; the two mold halves 11 slide and close together to form the cavity to be pressed 16 and the extrusion working section 17, and the billet 5 is located in the cavity to be pressed 16 to be pressed;

[0046] 5) Extrusion; The upper die holder 3 is driven down by the hydraulic press, and the upper die holder 3 drives the upper extrusion die rod 31 down so that its lower surface contacts the blank 5 and applies pressure. The telescopic cylinder 41 provides back pressure to the blank 5 through the ejector rod 4. The parameters of the hydraulic press driving the upper die holder 3 down can be controlled at 15 MPa (approximately 200 tons of pressure), and the parameters of the back pressure provided by the telescopic cylinder 41 through the ejector rod 4 can be controlled at 5 MPa (approximately 10 tons of pressure). The back pressure is less than the pressure of the upper die holder 3 down. The upper extrusion die rod 31 simultaneously pushes the blank 5 and the ejector rod 4 down. The blank 5 is pushed into the extrusion working section 17 and is extruded into working surfaces in all directions. During the extrusion forming process, the ejector rod 4 always provides back pressure to the blank 5, ensuring that the blank 5 will not be subjected to uneven stress or abnormal bending deformation during the entire cold forming process.

[0047] 6) Holding pressure; after the upper extrusion die rod 31 descends to the designed height, it stops pressing down and maintains that height, while the ejector rod 4 continues to provide back pressure to the billet 5; specifically, the upper extrusion die rod 31 descends so that the billet 5 passes through the extrusion working section 17 and is located in the clearance section below the extrusion working section 17 in the extrusion die 1, then stops descending, and holds pressure in conjunction with the ejector rod 4;

[0048] 7) After the pressure holding time is met, the upper extrusion die rod 31 moves upward and leaves the extrusion die 1. The ejector rod 4 no longer provides back pressure to the blank 5 but only serves as a bearing surface. The two halves of the die 11 slide open in opposite directions, and the extruded blank 5 can be easily removed.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a parking arm, characterized in that: This method is based on the manufacturing mold structure of a parking arm, which includes an extrusion mold. The extrusion mold is located between a fixed lower mold base and an upper mold base that can move vertically to perform the extrusion action. The extrusion mold has a cavity to be pressed and an extrusion working section that are connected vertically and pass through the extrusion mold. The extrusion mold is located on the lower mold base, and an upper extrusion rod that can move with the upper mold base and extend into the extrusion mold is connected to the upper mold base. A push rod that can extend into the extrusion mold is provided through the lower mold base to extend to the cavity to be pressed during extrusion to support the material. The push rod is connected to a telescopic cylinder that drives its vertical movement to descend to the lower end of the extrusion working section during the extrusion process and provide back pressure. The extrusion die adopts a split die structure, comprising two halves of the die that are separated into left and right halves. The two halves of the die are slidably mounted on the lower die base to facilitate loading and unloading. The cavity to be pressed and the extrusion working section are also machined in half on the two halves of the die so that they are formed when the two halves of the die are closed together. The cross-section of the cavity to be pressed is larger than the cross-section of the extrusion working section, and there is a smooth and continuous slope transition between the cavity to be pressed and the extrusion working section. The lower end of the extrusion working section is also set in a circumferentially enlarged and recessed form, and its cross-section corresponds to that of the cavity to be pressed. The upper surface contour shape of the ejector rod corresponds to the cross-section of the extrusion working section. The lower surface contour shape of the upper extrusion die rod also corresponds to the cross-section of the extrusion working section. This method includes the following steps: 1) Feeding: The ejector rod extends to the cavity to be pressed, and the two mold halves slide open in opposite directions, placing the blank on the upper surface of the ejector rod; 2) Mold closing; the two mold halves slide and close together to form a cavity to be pressed and an extrusion working section, and the billet is located in the cavity to be pressed; 3) Extrusion; The upper die presses down, driving the upper extrusion die rod to move downward so that its lower surface contacts the blank and applies pressure. The telescopic cylinder provides back pressure to the blank through the ejector rod. The back pressure is less than the pressure of the upper die pressing down. The upper extrusion die rod simultaneously pushes the blank and the ejector rod downward. The blank is pushed into the extrusion working section and is extruded into the working surfaces of each circumference. During the extrusion process, the ejector rod always provides back pressure to the blank. 4) Holding pressure; After the upper extrusion die rod descends to the designed height, it stops pressing down and maintains that height, while the ejector rod continues to provide back pressure to the billet; Specifically, the upper extrusion die rod moves downwards, causing the billet to pass through the extrusion working section and then be located in the clearance section below the extrusion working section inside the extrusion die. The downward movement stops, and pressure is maintained in conjunction with the ejector rod. 5) Unloading: After the pressure holding time is met, the upper extrusion die rod moves upward and leaves the extrusion die. The ejector rod no longer provides back pressure to the billet but only serves as a bearing surface. The two halves of the die slide open in opposite directions and the extruded billet is removed.

2. The method for manufacturing a parking arm according to claim 1, characterized in that: The two mold halves are respectively connected to a horizontal drive mechanism to enable the two mold halves to slide towards and away from each other on the lower mold base.

3. The method for manufacturing a parking arm according to claim 2, characterized in that: The horizontal drive mechanism is a telescopic cylinder.

4. The method for manufacturing a parking arm according to claim 1, characterized in that: A lower die washer is provided between the extrusion die and the lower die base. The lower die washer is fixed to the lower die base. A recessed groove is provided on the upper surface of the lower die washer. The lower surfaces of the two die halves are respectively provided with raised slide rails that are adapted to the slide rails. The two die halves are placed on the lower die washer and can slide along the movement direction of the slide rails and the slide rails. The ejector rod passes through the lower die washer.

5. The method for manufacturing a parking arm according to claim 1, characterized in that: Before step 1), the billet is forged, and the cross-section of the billet after forging corresponds to the cross-section of the extrusion section, but it still has a small amount of thickness allowance on one side compared to the extrusion section; the cross-section of the cavity to be pressed is larger than the cross-section of the billet after forging.

Images