A method for hot-press injection molding of composite material control arm

Abstract

A method for hot-press injection molding of a composite material control arm is disclosed. The resulting control arm structure includes a composite sheet with pin holes and needle holes, a rubber body, a ball pin, and a bushing. The mold used for hot-press injection molding has a rear mold with positioning pins, positioning holes, and a positioning cylinder. During molding, the composite sheet is hung on the positioning pins through its pin holes, the bushing is fitted onto the positioning cylinder, and the ball pin is inserted into the positioning hole through its pin shaft. Then, the front mold presses the composite sheet, bending its edges to form a concave shape. Finally, plastic is injected to form the rubber body, combining the composite sheet, ball pin, and bushing into a whole. The bushing has ribs extending circumferentially on its outer side. During injection molding, the two ends of the composite sheet rest on the outer side of a bushing's rib. By setting the ribs, the distance between the composite sheet and the outer circumference of the bushing is maintained, allowing the rubber to flow between the composite sheet and the bushing. This enables the pre-forming and injection molding of the skeleton to be completed on a single mold, resulting in stable product quality.

Description

Technical Field

[0001] This invention relates to a molding method for a composite material control arm, specifically a hot-press injection molding method for integrally molding a composite material control arm. Background Technology

[0002] Vehicle weight is a crucial factor affecting the extended driving range of new energy vehicles. Component suppliers, vehicle manufacturers, and research institutions are all engaged in research on lightweighting technologies for new energy vehicles. The application of lightweighting technologies in new energy vehicles can not only reduce overall vehicle energy consumption but also effectively improve acceleration performance, braking performance, handling stability, ride comfort, and noise and vibration levels. Currently, the development of lightweighting in new energy vehicles increasingly focuses on the hybrid application of multiple materials. Among these, the hybrid application of continuous fiber-reinforced thermoplastic composites as the main load-bearing framework, with high-glass fiber engineering plastics playing a connecting, coordinating, and reinforcing role, shows the greatest promise.

[0003] For example, the applicant's previously published invention patent application, CN202110177255.5, entitled "A Method for Molding a Control Arm and a Control Arm," first uses a strip of thermoplastic continuous fiber-reinforced composite material to create a V-shaped closed skeleton. Then, the V-shaped closed skeleton is placed in an injection mold, and thermoplastic fiber-reinforced composite material is used for high-pressure injection molding to fill the V-shaped closed skeleton and integrally injection molded to form the control arm. This method requires a separate pre-molding process, where the reinforcing skeleton is prepared in advance outside the injection mold, and then transferred to the injection mold for secondary injection molding, thus resulting in low efficiency.

[0004] For example, the invention patent application CN202110745630.1, entitled "A Composite Material Control Arm for Vehicles and Its Molding Method," first prepares a carbon fiber composite plate, and then places the carbon fiber composite plate and the bushing together into a mold for injection molding. However, this method does not specifically explain how to maintain the accurate relative position of the carbon fiber composite plate and the bushing during the injection molding process, so it is impossible to know whether this method can produce a control arm that meets the requirements. Summary of the Invention

[0005] This invention addresses the current lack of detailed methods for the integrated hot-press injection molding of control arms by proposing a method for the integrated hot-press injection molding of composite material control arms. This method achieves both pre-forming and injection molding of the frame using a single mold, and produces control arms with stable quality that meets usage requirements.

[0006] The technical means adopted by the present invention to solve the above problems is as follows: a method for hot-press injection molding of a composite material control arm, wherein the part structure of the control arm after molding includes a composite sheet with pin holes and pin holes, a rubber body, a ball pin and a bushing. The mold for hot-press injection molding has a positioning pin, a positioning hole and a positioning cylinder in the rear mold. During molding, the composite sheet is hung on the positioning pin through its pin holes, the bushing is sleeved on the positioning cylinder, and the ball pin is inserted into the positioning hole through its pin shaft. Then, the front mold squeezes the composite sheet to bend its edge to form a concave shape. Finally, plastic is injected to form the rubber body, which combines the composite sheet, the ball pin and the bushing into a whole. The bushing has a rib extending in the circumferential direction on its outer side. During injection molding, the two ends of the composite sheet are respectively placed on the outside of the rib of a bushing.

[0007] Furthermore, there are two raised ribs, and during injection molding, the end of the composite sheet is flush with one end of the raised rib.

[0008] Furthermore, the length of the raised rib is one-quarter of the outer perimeter of the bushing.

[0009] Furthermore, a notch is provided at one end face of the bushing, and a protrusion is provided on the positioning cylinder at the position opposite to the notch. After the bushing is positioned on the positioning cylinder through the notch and the protrusion, the composite plate can be deformed and placed on the outside of the bushing's rib.

[0010] Furthermore, there are two notches on one bushing and two corresponding protrusions on the positioning cylinder.

[0011] Furthermore, the two notches of a bushing are respectively located at their ends parallel to the two ends of the rib; the two protrusions on a positioning cylinder are respectively located at the lowest and outermost ends of the end face away from its free end.

[0012] Furthermore, the rear mold core has multiple inserts protruding towards the front mold, with gaps between the inserts, through which positioning pins pass. During injection molding, plastic material flows through the gaps between the inserts, forming reinforcing ribs inside the control arm after molding.

[0013] Furthermore, the inner and outer sides of the V-shaped integral formed by the insert are provided with multiple positioning blocks whose height is smaller than that of the insert. When the composite sheet is extruded by the front mold, the edge of the composite sheet contacts the positioning blocks, so that there is a certain gap between the composite sheet and the insert. During the injection molding process, the space between the composite sheet and the reinforcing rib is filled with rubber material, which increases the contact area between the rubber material and the composite sheet and improves the bonding force.

[0014] Furthermore, the surface of the positioning block away from the insert has a slope, and its bottom thickness is greater than its top thickness.

[0015] Furthermore, the rear mold is also equipped with a slider, and the positioning cylinder is set on the slider, which drives the positioning cylinder to move left and right.

[0016] Furthermore, the rear mold is also equipped with a spring and a positioning plate. One end of the positioning pin is fixed to the positioning plate, and the spring pushes the positioning plate to push the other end of the positioning pin out of the insert.

[0017] The beneficial effects of this invention are:

[0018] 1. The present invention provides support for the composite sheet by setting ribs on the surface of the bushing when the front mold pushes the composite sheet, thereby avoiding contact between the composite sheet and the bushing and ensuring the distance between the composite sheet and the bushing.

[0019] 2. The present invention provides a notch in the bushing and a corresponding protrusion in the positioning cylinder. The bushing is positioned by the cooperation of the notch and the protrusion, ensuring the correct position between the composite sheet and the rib. This ensures that the rib is fully attached to the composite sheet. After injection molding, the gap where the rib is located is completely wrapped between the composite sheet and the adhesive.

[0020] 3. The present invention sets positioning blocks on both sides of the insert. After the front mold extrudes the composite sheet, the positioning blocks separate the composite sheet from the side of the insert, so that the composite sheet is attached to the inner surface of the front mold. There is a gap between the composite sheet and the insert. During the injection molding process, the rubber material will not go to the outside of the composite sheet, but will fill the inside of the composite sheet. This ensures both the uniformity of the control arm shape and the bonding strength between the rubber material and the composite sheet.

[0021] 4. The present invention uses positioning pins that can extend out of the insert surface and be pressed into the insert to hold the composite sheet, so that the composite sheet can be positioned in the mold without falling off.

[0022] 5. The present invention uses a slider to move the positioning cylinder left and right, so that the bushing can be fitted onto the positioning cylinder before molding, and can be easily demolded after hot pressing injection molding. Attached Figure Description

[0023] Figure 1 Here is a schematic diagram and exploded view of the control arm structure in Embodiment 1;

[0024] Figure 2 This is a schematic diagram of the composite sheet structure in Example 1;

[0025] Figure 3 This is an enlarged structural schematic diagram of the bushing and its notch in Embodiment 1;

[0026] Figure 4 This is a schematic diagram of the structure of the core surface of the model after Example 1;

[0027] Figures 5-7 All Figure 4 Enlarged view of a portion;

[0028] Figure 8 This is a schematic diagram showing the dimensional relationship between the rear mold insert and the positioning block in Example 1;

[0029] Figure 9 This is a schematic diagram of the internal structure of the rear mold in Example 1;

[0030] Figure 10 for Figure 9 Schematic diagram of the structure after removing the baffle;

[0031] Figure 11 This is a schematic diagram of the baffle structure in Example 1;

[0032] Figure 12 This is a schematic diagram of the front mold structure in Example 1;

[0033] In the diagram: 1. Front mold, 2. Rear mold, 201. Insert, 202. Positioning pin, 203. Positioning hole, 204. Positioning block, 205. Positioning cylinder, 2051. Protrusion, 206. Fixing post, 2061. Fixing hole, 207. Slider, 208. Power mechanism, 210. Positioning plate, 211. Spring, 212. Baffle, 2121. Blind hole, 3. Control arm, 31. Reinforcing body, 32. Rubber body, 33. Bushing, 331. Rib, 332. Notch, 34. Ball pin, 341. Pin shaft, 300. Composite sheet, 301. Pin hole, 302. Pin hole, 303. Cutout. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings. The drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Example 1

[0035] A method for hot-press injection molding of a composite material control arm, such as Figure 1 As shown, the control arm 3 after molding in this embodiment is V-shaped in general, including a reinforcing body 31, a rubber body 32, a bushing 33 and a ball pin 34. There are two bushings 33, which are located at both ends of the V-shape of the control arm 3 respectively. One ball pin 34 is located at the V-shaped connection, and the pin shaft 341 of the ball pin 34 protrudes out of the rubber body 32.

[0036] Before molding, such as Figure 2 As shown, the outer wall of the V-shaped composite sheet 300 at the V-shaped connection has two notches 303, and the inner wall has one notch 303. A pin hole 301 is located at the center of the V-shaped connection, and pinholes 302 are provided on both walls. Figure 3As shown, a raised rib 331 is provided on the outer side of the bushing 33 along its circumference. Preferably, there are two raised ribs 331, each with a length of about one-quarter of the outer circumference of the bushing 33.

[0037] During molding, the composite sheet 300, bushing 33 and ball pin 34 are first installed into the rear mold, and then the front mold presses the composite sheet 300 into the shape of the reinforcement 31 during the mold closing process, and finally injection molding is performed.

[0038] like Figure 4 As shown, inserts 201 are provided in the rear mold. Multiple inserts 201 are V-shaped as a whole, with gaps between them. During injection molding, the plastic material flows through these gaps, forming reinforcing ribs for the control arm. For example... Figure 5 As shown, the rear mold is also provided with multiple positioning pins 202. It is best that each positioning pin 202 passes through the insert 201, rather than through the gap between the inserts 201, so as not to obstruct the flow of the rubber material in the gap, and thus not to affect the strength of the reinforcing rib. The V-shaped connection formed by the inserts 201 is provided with positioning holes 203. The size and shape of the positioning holes 203 match the pin shaft 341 of the ball pin 34. During molding, the ball pin 34 is fixed to the rear mold after its pin shaft 341 is inserted into the positioning hole, and the composite sheet 300 is fitted onto the ball pin 34 through its pin hole 301.

[0039] like Figure 4 and Figure 6 As shown, positioning cylinders 205 are provided at both ends of the V-shaped opening formed by the rear mold insert 201. The ends of the two positioning cylinders 205 that are close to each other are free ends. The bushing 33 is fitted onto the positioning cylinder 205 from the free end. The other end of the positioning cylinder 205 is connected to the slider 207. The slider 207 is connected to a power mechanism 208 that drives it to move left and right, thereby causing the two positioning cylinders 205 to move closer or further apart. The power mechanism 208 can be a cylinder or a hydraulic cylinder, etc. To prevent the bushing 33 from slipping off the positioning cylinder 205 during molding, such as... Figure 4 and Figure 7 As shown, a fixing post 206 is provided between the two positioning cylinders 205, and fixing holes 2061 are provided at both ends of the fixing post 206. During molding, the power mechanism 208 pushes the slider 207 to make the free end of the positioning cylinder 205 press against the fixing hole 2061, thereby blocking the bushing 33 so that it will not fall off.

[0040] To maintain the distance between the end of the reinforcement 31 formed by the composite sheet 300 and the outer peripheral surface of the bushing 33 during injection molding, the composite sheet 300 must rest on the rib 331 during hot pressing. Therefore, it is essential to ensure that the bushing 33 does not rotate during injection molding. Figure 3 As shown, two notches 332 are provided on one end face of the bushing 33 at a position parallel to the two ends of its rib 331. Correspondingly, as... Figure 6As shown, each positioning cylinder 205 has two protrusions 2051 at its lowest and outermost ends, which are located away from its free end. These protrusions 2051 match the positions of the notches 332. Through the cooperation of the notches 332 and the protrusions 2051, the bushing 33's rib 331 is fixed in the lower half-circle position of the rear mold near the front mold. In this way, although the bushings 33 are used in pairs, the position of the notches 332 does not affect whether the bushing 33 is used for the left or right positioning cylinder 205. Of course, other numbers of notches 332 and protrusions 2051 can also be provided, and the notches 332 and protrusions 2051 can also be placed in other positions, as long as the rib 331 can be positioned in the lower half-circle position of the rear mold near the front mold.

[0041] like Figure 5 As shown, positioning blocks 204 are provided on both the inner and outer sides of the V-shaped straight edge formed by the insert 201, and the height of the positioning blocks 204 is less than the height of the insert 201, that is, as shown in the figure. Figure 8 As shown, the upper surface b of the positioning block 204 is lower than the upper surface c of the insert 201; the surface a of the positioning block 204 away from the insert 201 is an inclined surface, that is, the width W2 of the bottom of the positioning block 204 is greater than the width W1 of its top.

[0042] Furthermore, the positioning pin 202 protrudes from the surface of the insert 201 in the initial state, such as Figures 9-10 As shown, the rear mold 2 has a positioning plate 210, a spring 211, and a baffle 212 inside. One end of the positioning pin 202 is mounted on one surface of the positioning plate 210 (not visible in the figure), and the other end passes through the rear mold core and extends from the surface of the insert 201. The spring 211 is located on the other side of the positioning plate 210 away from the positioning pin 202. Figure 11 As shown, the baffle 212 has a blind hole 2121. One end of the spring 211 extends into the blind hole 2121, and the other end pushes the positioning plate 210, so that there is a certain distance between the positioning plate 210 and the baffle 212 (of course, the depth of the blind hole 2121 must be less than the length of the spring 211 in the relaxed state). The positioning plate 210 also pushes the positioning pin 202. When the mold is closed, the front mold 1 encounters the positioning pin 202 and squeezes the spring 211, so that the positioning plate 210 moves toward the baffle 212, and the positioning pin 202 is pushed to be flush with the insert 201.

[0043] like Figure 12 As shown, there are three recessed groove-shaped spaces at the core of the front mold 1, which are roughly triangular in shape and together with the core of the rear mold 2, form the cavity space during hot-pressing injection molding.

[0044] The specific molding method is as follows: First, the pin 341 of the ball pin 34 is inserted into the positioning hole 203 of the rear mold 2. The composite sheet 300 is hung on the positioning pin 202 through its pin hole 302, and the pin hole 301 of the composite sheet 300 is fitted onto the ball pin 34. The bushing 33 is fitted onto the positioning cylinder 205. Of course, the notch 332 of the bushing 33 must match the protrusion 2051 of the positioning cylinder 205 so that the rib 331 is located in the appropriate position of the mold. Then, the power mechanism 208 pushes the slider 207 to move, so that the free end of the positioning cylinder 205 presses against the fixing hole 2061. Finally, the mold is closed and hot-pressed for injection molding.

[0045] During mold closing, the front mold 1 pushes the composite sheet 300, deforming its edges to form a concave reinforcement 31. In this process, the front mold 1 pushes the edge of the composite sheet 300 (i.e., the reinforcement 31) to the inclined surface a of the positioning block 204, ensuring a certain gap between the insert 201 at the V-shaped edge and the reinforcement 31. During injection molding, the plastic material flows into this gap and bonds with the reinforcement 31. By setting the side of the positioning block 204 away from the insert 201 as an inclined surface, the deformation of the composite sheet 300 is guided, reducing the precision requirements for the edge dimensions of the composite sheet 300. Therefore, the number and size of the positioning blocks 204 must ensure that the edge of the reinforcement 31 does not wrinkle and adhere to the insert 201, preventing the plastic material from flowing out of the reinforcement 31 during injection molding, while also ensuring sufficient distance between the positioning blocks 204 to allow the plastic material to fill and bond with the reinforcement 31. Meanwhile, the edge D ( ) of the composite sheet after deformation of 300 Figure 2 (as shown) and the bottom d of the rear mold 2 insert 201 ( Figure 8 There is still a certain distance between them (as shown), so that the adhesive can wrap the edge of the composite sheet 300.

[0046] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which should be defined by the claims.

Claims

1. A method of thermo-compression injection molding an integrated composite control arm, the method comprising: The part structure of the control arm after forming includes a composite sheet (300), a rubber body (32), a ball pin (34) and a bushing (33), a mold for hot pressure injection has a back mold (2) provided with a positioning needle (202), a positioning hole (203) and a positioning cylinder (205), during forming, the composite sheet (300) is hung on the positioning needle (202), the bushing (33) is sleeved on the positioning cylinder (205), the ball pin (34) is inserted into the positioning hole (203), then the front mold (1) extrudes the composite sheet (300) to make the edge thereof bent to form a concave type, finally, plastic is injected to form the rubber body, and the composite sheet (300), the ball pin (34) and the bushing (33) are combined into an integral whole; and the outer side of the bushing (33) is provided with a protruding rib (331) extending in the circumferential direction, during injection, two ends of the composite sheet (300) are respectively placed outside the protruding rib (331) of one bushing (33). ​ A notch (332) is arranged at one end surface of the bushing (33), and a protrusion (2051) is arranged at a position opposite to the notch (332) on the positioning cylinder (205), after the bushing (33) is positioned on the positioning cylinder (205) through the notch (332) and the protrusion (2051), the composite sheet (300) can be placed outside the protruding rib (331) of the bushing (33) after deformation. The notch (332) on one bushing (33) has two, and the corresponding protrusions (2051) on the positioning cylinder (205) also have two, the two notches (332) of one bushing (33) are respectively arranged at positions parallel to two ends of the protruding rib (331) at the end portions thereof.

2. The method of claim 1, wherein: The protruding rib (331) has two, and during injection, the end of the composite sheet (300) is flush with one end of the protruding rib (331).

3. The method of claim 1, wherein: The length of the protruding rib (331) is one fourth of the outer circumference of the bushing (33).

4. The method of claim 1, wherein: The core of the back mold (2) is provided with a plurality of inserts (201) protruding towards the front mold (1), gaps are arranged between the inserts (201), and the positioning needle (202) passes through the inserts (201).

5. The method of claim 4, wherein: The inner and outer sides of the V-shaped whole formed by the inserts (201) are respectively provided with a plurality of positioning blocks (204) with a height smaller than that of the inserts (201).

6. The method of claim 5, wherein: The surface of the positioning block (204) away from the insert (201) has an inclination, and the thickness of the bottom of the positioning block (204) is greater than that of the top.

7. The method of claim 1, wherein: The back mold (2) is further provided with a sliding block (207), and the positioning cylinder (205) is arranged on the sliding block (207) and moves left and right through the sliding block (207).

8. The method of claim 1, wherein: The back mold (2) is further provided with a spring (211) and a positioning plate (210), one end of the positioning needle (202) is fixed to the positioning plate (210), and the spring (211) pushes the positioning plate (210) to extrude the other end of the positioning needle (202) out of the insert (201).

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