Shifting fork plastic coating mold with floating positioning function and application method of shifting fork plastic coating mold

Abstract

The invention relates to the technical field of shifting fork plastic coating treatment, in particular to a shifting fork plastic coating mold with a floating positioning function and an application method of the shifting fork plastic coating mold. The shifting fork plastic coating mold comprises an upper mold assembly, a lower mold assembly and a floating positioning assembly. The floating positioning assembly is composed of an upper floating positioning sub-assembly and a lower floating positioning sub-assembly. In the mold closing process, the upper floating positioning sub-assembly gradually gets close to the lower floating positioning sub-assembly, the posture of the lower floating positioning sub-assembly is changed due to the acting force from the upper floating positioning sub-assembly in a subsequent certain time period, and the fork feet of the shifting fork are positioned. The limiting force acting on the shifting fork feet is elastic force, the force value can be adjusted in real time according to the impact force of the high-pressure thermoplastic plastic fluid borne by the shifting fork feet, and the limit is that the shifting fork feet do not elastically deform, so that the size of an opening is accurately controlled after the shifting fork is coated with plastic, and the service life of the shifting fork is prolonged. And the thickness values of the plastic-coated layers in different areas on the fork feet of the shifting fork are basically consistent.

Description

Technical Field

[0001] The invention relates to the technical field of plastic coating treatment of a shift fork, in particular to a plastic coating mold for a shift fork with a floating positioning function and an application method thereof. Background Art

[0002] The shift fork is an important component of the car's gearbox. It is connected to the speed shift handle and is located at the lower end of the handle. Its main function is to shift the intermediate speed wheel to change the input or output speed ratio, realize clutch shifting, and ensure that the car can change speed smoothly during driving.

[0003] After the fork is machined or cast, in order to improve its impact resistance, its fork legs are usually coated with plastic, and the fork legs are completely wrapped with thermoplastic plastic. As far as the current technical status is concerned, the fork plastic coating mold consists of an upper mold assembly and a lower mold assembly. Among them, the upper mold assembly includes an upper mold plate, an upper mold core, and an upper mold cavity insert. The upper mold core uses the upper mold plate as the installation base. The upper model cavity insert is embedded in the upper mold core. The lower mold assembly includes a lower mold plate, a lower mold core, and a lower model cavity insert. The lower mold core uses the lower mold plate as the installation base. The lower model cavity insert is embedded in the lower mold core. The upper model cavity insert and the lower model cavity insert are respectively formed with an upper plastic coating sub-cavity and a lower plastic coating sub-cavity for accommodating and limiting the fork legs. In the open mold state, the fork is placed in the lower plastic coating sub-cavity. After the mold is closed, the mold assembly and the lower mold assembly are closed, and the upper plastic-coated sub-cavity and the lower plastic-coated sub-cavity are combined to form a plastic-coated cavity. Then, the thermoplastic fluid is filled into the plastic-coated cavity by means of an injection molding machine, and the shift fork is covered with thermoplastic plastic. However, in actual operation, the following problems are found: the opening size tolerance of the plastic-coated shift fork (acceptance standard is ±0.15mm) is seriously out of tolerance, and the thickness of the plastic-coated layer in different areas on the fork leg is quite different. The reason is that the cavity size of the upper plastic-coated sub-cavity and the lower plastic-coated sub-cavity is difficult to be completely consistent with the fork leg of the limit shift fork. In the case where the cavity size is too large, after the mold is closed, the fork legs placed in the cavity are not effectively limited and are completely free. In this way, the relative position of the fork legs changes due to the impact of the high-pressure thermoplastic fluid, which directly leads to large differences in the thickness of the plastic coating layer in different areas of the fork legs, or the fork legs undergo temporary elastic deformation, which directly leads to serious deviations in the opening size tolerance of the fork after plastic coating. In the case where the cavity size is too small, after the mold is closed, the fork legs are difficult to enter the cavity smoothly, which will affect the efficiency and quality of plastic coating. Furthermore, even if the fork legs are forced to enter the cavity under strong force, their freedom of movement is completely restricted, and the fork legs are affected by the opposite force. The opening design size of the fork legs changes, which makes it difficult to accurately control the opening size tolerance of the plastic coated fork. Therefore, it is urgent for technical personnel in this field to solve the above problems. Summary of the invention

[0004] Therefore, in view of the above existing problems and defects, the project development team of the present invention collected relevant information, conducted multiple evaluations and considerations, and continuously experimented and modified the project development team, which ultimately led to the emergence of the fork overmolding mold with floating positioning function.

[0005] In order to solve the above technical problems, the present invention relates to a shift fork overmolding mold with floating positioning function, including an upper mold assembly and a lower mold assembly. The upper mold assembly and the lower mold assembly respectively correspond to the movable template and the fixed template of the injection molding machine as the installation basis. Before pre-molding, the upper mold assembly and the lower mold assembly are closed to form a pouring system and an overmolding cavity. After the overmolding is completed, the upper mold assembly and the lower mold assembly are separated to take out the shift fork overmolded part. Furthermore, the shift fork overmolding mold with floating positioning function also includes a floating positioning assembly. The floating positioning assembly is composed of an upper floating positioning subassembly with the upper mold assembly as the assembly basis and a lower floating positioning subassembly with the lower mold assembly as the assembly basis. In the mold closing process, the upper floating positioning subassembly gradually approaches the lower floating positioning subassembly, and in a subsequent certain period of time, the lower floating positioning subassembly undergoes a posture change due to the force from the upper floating positioning subassembly, and the shift fork legs are positioned by the elastic side top force from the lower mold assembly.

[0006] As a further improvement of the technical solution disclosed in the present invention, the upper mold assembly includes an upper mold plate, an upper mold core and an upper model cavity insert. The upper mold core uses the upper mold plate as an installation base. The upper model cavity insert is embedded in the upper mold core and is flush with the bottom wall of the upper mold core. The lower mold assembly includes a lower mold plate, a lower mold core and a lower model cavity insert. The lower mold core uses the lower mold plate as an installation base. The lower model cavity insert is embedded in the lower mold core and is flush with the top wall of the lower mold core. The bottom wall of the upper model cavity insert is recessed upward to form an upper plastic-coated sub-cavity. The top wall of the lower model cavity insert is recessed downward to form a lower plastic-coated sub-cavity. Before pre-molding, the upper mold assembly and the lower mold assembly are closed, the upper plastic-coated sub-cavity and the lower plastic-coated sub-cavity are combined, and the plastic-coated cavity is formed.

[0007] As a further improvement of the technical solution disclosed in the present invention, the upper floating positioning subassembly includes a pressure member, a self-locking pressure block, an upper spring member and a stop bolt. The bottom wall of the upper mold plate extends upward to form an upper mounting cavity for inserting the upper spring member. The top wall of the upper mounting cavity continues to extend upward to form a bolt through hole for the stop bolt to pass freely. The bottom wall of the upper mold core extends upward to form a through-shaped upper sliding cavity for inserting the self-locking pressure block and communicating with the upper plastic-coated sub-cavity. The self-locking pressure block is inserted into the upper sliding cavity, and its side wall is in contact with the upper mold cavity insert. The stop bolt passes through the bolt through hole and the upper mounting cavity in sequence, and is mechanically connected to the self-locking pressure block by means of a threaded pair. The upper spring member is built into the upper mounting cavity, and is axially penetrated by the stop bolt, and its upper and lower end faces are elastically pressed against the top wall of the upper mounting cavity and the top wall of the self-locking pressure block respectively and one by one. The pressure piece is used to directly apply force to the lower floating positioning subassembly, and it is detachable to achieve fixation with the self-locking pressure block. The lower floating positioning subassembly includes a horizontal floating sliding member, a vertical floating sliding member, a lower spring member and a side spring member. The top wall of the lower die core extends downward to form a lower special-shaped sliding cavity for simultaneously loading the vertical floating sliding member and the lower spring member and reaching the lower die core. The horizontal floating sliding member is formed with an inclined wall sliding notch for the vertical floating sliding member to freely pass through. The left side wall of the horizontal floating sliding member continues to extend to the left to form an extended ejection arm. The vertical floating sliding member is beveled to form a sliding guide inclined surface on its upper end that matches the inclined wall sliding notch. When the horizontal floating sliding member is assembled relative to the lower mold core, the vertical floating sliding member longitudinally passes through the inclined wall sliding notch, the lower spring member is elastically pressed between the lower mold plate and the vertical floating sliding member, the side spring member is elastically pressed between the lower mold core and the horizontal floating sliding member, and the extended ejector arm is supported on the top wall of the lower mold cavity insert. Under the coordinated action of the lower spring member and the side spring member, the sliding guide inclined surface is able to contact the inclined wall of the inclined wall sliding notch. During the mold closing process, the upper mold assembly performs a displacement movement toward the lower mold assembly. The vertical floating sliding member performs a downward movement in a direction along the lower special-shaped sliding cavity due to the downward pressure from the pressure member, and the lower spring member undergoes compression deformation. At the same time, the sliding guide slope avoids to the left, and the horizontal floating sliding member is able to perform a translational movement to the left under the elastic side thrust from the side spring member until the extended push arm touches the fork leg of the shift fork, and then the upper mold assembly continues to move downward until the horizontal floating sliding member is tightly pressed by the self-locking pressure block, and the planar kinematic freedom of the horizontal floating sliding member is limited to zero.

[0008] As a further improvement of the technical solution disclosed in the present invention, the self-locking pressing block is beveled to form an upper self-locking inclined surface at its lower end. The horizontal floating sliding member is beveled to form a lower self-locking inclined surface at its upper end that matches the upper self-locking inclined surface.

[0009] As a further improvement of the technical solution disclosed in the present invention, the inclination angle between the sliding guide inclined surface and the horizontal plane is α, and the inclination angle between the lower self-locking inclined surface and the horizontal plane is β, then 90°≤α≤110°, 6°≤β≤15°.

[0010] As a further improvement of the technical solution disclosed in the present invention, the pressure member is preferably a round head bolt. The pressure member is mechanically connected to the self-locking pressure block by means of a thread pair.

[0011] As a further improvement of the technical solution disclosed in the present invention, the upper floating positioning subassembly also includes a stroke adjustment gasket. The stroke adjustment gasket is used to limit the lower limit value of the distance d between the head of the stop bolt and the upper template, and is sleeved on the stop bolt.

[0012] Furthermore, the present invention also discloses an application method of a shift fork overmolding mold with a floating positioning function, which is implemented by means of the shift fork overmolding mold with a floating positioning function, and comprises the following steps:

[0013] S1. In the mold opening state, place the shift fork on the lower mold assembly, and position its fork foot relative to the lower plastic-coated cavity;

[0014] S2, start the injection molding machine, the upper mold assembly performs displacement movement toward the lower mold assembly, and at the same time, the upper floating positioning subassembly gradually approaches the lower floating positioning subassembly until the pressure member and the vertical floating sliding member are in critical contact;

[0015] S3, the upper die assembly continues to move downward, the vertical floating sliding member moves downward along the lower special-shaped sliding cavity due to the downward pressure from the pressure member, the lower spring member is compressed and deformed, at the same time, the sliding guide inclined surface moves to the left, and the horizontal floating sliding member moves to the left under the elastic side thrust from the side spring member until the extended push arm touches the fork foot;

[0016] S4, the upper die assembly performs downward movement again, and the self-locking pressing block continues to approach the horizontal floating sliding member, and in this process, the horizontal floating sliding member does not perform translational movement, and its plane kinematic freedom is not restricted;

[0017] S5. The horizontal floating sliding member is pressed against by the self-locking pressure block, and the planar kinematic freedom of the horizontal floating sliding member is restricted to zero. At the same time, the upper mold assembly and the lower mold assembly are closed, the casting system is formed, and the upper plastic-coated sub-cavity and the lower plastic-coated sub-cavity are combined to form a plastic-coated cavity.

[0018] As a further improvement of the technical solution disclosed in the present invention, in steps S2, S3, and S4, the upper limits of the downward movement speed of the upper mold assembly are V1, V2, and V3, respectively, and V1, V2, and V3 show an exponential decreasing law.

[0019] In practical applications, the fork overmolding mold with floating positioning function disclosed in the present invention can achieve at least the following beneficial technical effects, specifically:

[0020] 1) The shift fork overmolding mold is equipped with a floating positioning component. And according to the actual assembly position, the floating positioning component is divided into an upper floating positioning sub-component and a lower floating positioning sub-component. When the mold is closed, the relative position of the shift fork legs in the overmolding cavity is limited. Furthermore, considering that the limiting force acting on the shift fork legs is an elastic force, and the force value can be adjusted in real time according to the impact force of the high-pressure thermoplastic fluid on the shift fork legs, the shift fork legs must not be elastically deformed. Taking the above factors into consideration, on the one hand, the opening size of the shift fork is precisely controlled after overmolding to ensure that its tolerance value is within the design allowable value range; on the other hand, the overmolding quality is good, which is specifically reflected in: after overmolding, the thickness of the overmolding layer in different areas on the shift fork legs is basically the same;

[0021] 2) During the mold closing process, the moving template performs a downward movement, thereby driving the upper mold assembly to perform a displacement movement toward the lower mold assembly. At the same time, the upper floating positioning subassembly gradually approaches the lower floating positioning subassembly until the critical top contact, and then the moving template continues to move downward, and the lower floating positioning subassembly undergoes a posture change due to the force from the upper floating positioning subassembly. From the above description, it can be seen that the initial power source for the posture change of the lower floating positioning subassembly comes from the injection molding machine, and there is no need for an independent matching power source. Therefore, under the premise that its floating positioning function is ensured, the fork overmolding mold has a very simple design structure, which lays a good foundation for reducing its manufacturing difficulty and manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 The invention discloses a structural schematic diagram of a shift fork plastic overmolding mold with a floating positioning function.

[0024] Figure 2 The present invention is a schematic structural diagram of an upper mold component and an upper floating positioning sub-component in a shift fork plastic overmolding mold with a floating positioning function disclosed in the present invention after being assembled.

[0025] Figure 3 The invention discloses a stereoscopic schematic diagram of an upper mold component and an upper floating positioning sub-component in a shift fork plastic overmolding mold with a floating positioning function after being assembled.

[0026] Figure 4 The present invention is a schematic structural diagram of a shift fork plastic overmolding mold with a floating positioning function after the lower mold component and the lower floating positioning sub-component are assembled.

[0027] Figure 5 The invention is a three-dimensional schematic diagram of a lower mold component and a lower floating positioning sub-component in a plastic overmolding mold for a shift fork with a floating positioning function after being assembled.

[0028] Figure 6 The invention discloses a schematic diagram of the operation process of the shift fork overmolding mold with floating positioning function.

[0029] Figure 7 yes Figure 6 A partial enlarged view of I.

[0030] Figure 8 yes Figure 6 A partial enlarged view of II.

[0031] Fig. 9 yes Figure 6 A partial enlarged view of III.

[0032] Fig.10 yes Figure 6 A partial enlarged view of IV.

[0033] Fig.11 yes Figure 6 A partial enlarged view of V.

[0034] 1-upper mold assembly; 11-upper mold plate; 111-upper installation cavity; 112-bolt through hole; 12-upper mold core; 121-upper sliding cavity; 13-upper mold cavity insert; 131-upper plastic-coated sub-cavity; 2-lower mold assembly; 21-lower mold plate; 22-lower mold core; 221-lower special-shaped sliding cavity; 23-lower mold cavity insert; 231-lower plastic-coated sub-cavity; 3-floating positioning assembly; 31-upper floating positioning sub-assembly; 311-pressure member; 3 12-self-locking pressure block; 3121-upper self-locking inclined surface; 313-upper spring member; 314-stop bolt; 315-stroke adjustment gasket; 32-lower floating positioning subassembly; 321-horizontally floating sliding member; 3211-inclined wall sliding notch; 3212-extended push arm; 3213-lower self-locking inclined surface; 322-vertical floating sliding member; 3221-sliding guide inclined surface; 323-lower spring member; 324-side spring member. DETAILED DESCRIPTION

[0035] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "left", "right", "up", "down", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0036] The following is a further detailed description of the present invention in conjunction with specific embodiments. Figure 1 The schematic diagram of the structure of the shift fork overmolding mold with floating positioning function disclosed in the present invention is shown. It can be seen that it is mainly composed of several parts such as an upper mold assembly 1, a lower mold assembly 2 and a floating positioning assembly 3. Among them, the upper mold assembly 1 and the lower mold assembly 2 respectively correspond to the movable template and the fixed template of the injection molding machine as the installation basis (not shown in the figure). Before pre-molding, the upper mold assembly 1 and the lower mold assembly 2 are closed to form a pouring system and an overmolding cavity. After the overmolding is completed, the upper mold assembly 1 and the lower mold assembly 2 are separated to take out the shift fork overmolded part. The floating positioning assembly 3 is composed of an upper floating positioning subassembly 31 with the upper mold assembly 1 as the assembly basis and a lower floating positioning subassembly 32 with the lower mold assembly 2 as the assembly basis. During the mold closing process, the upper floating positioning subassembly 31 gradually approaches the lower floating positioning subassembly 32, and in a subsequent period of time, the lower floating positioning subassembly 32 changes its posture due to the force from the upper floating positioning subassembly 31, and the fork legs are positioned by the elastic side push force from the lower mold assembly 2.

[0037] like Figure 2 , 3As shown in the figure, the upper mold assembly 1 is mainly composed of the upper mold plate 11, the upper mold core 12 and the upper mold cavity insert 13. The upper mold core 12 and the upper mold plate 11 are fixed together in a detachable manner. The upper mold cavity insert 13 is embedded in the upper mold core 12 and is flush with the bottom wall of the upper mold core 12. Figure 4 , 5 As shown in , the lower mold assembly 2 is mainly composed of several parts such as a lower mold plate 21, a lower mold core 22 and a lower mold cavity insert 23. The lower mold core 22 and the lower mold plate 21 are fixed as a whole in a detachable manner. The lower mold cavity insert 23 is embedded in the lower mold core 22 and is flush with the top wall of the lower mold core 22. The bottom wall of the upper mold cavity insert 13 is recessed upward to form an upper plastic-coated sub-cavity 131. The top wall of the lower mold cavity insert 23 is recessed downward to form a lower plastic-coated sub-cavity 231. Before pre-molding, the upper mold assembly 1 and the lower mold assembly 2 are closed, the upper plastic-coated sub-cavity 131 and the lower plastic-coated sub-cavity 231 are combined, and the plastic-coated cavity is formed.

[0038] Furthermore, by Figure 2 , 3 It can also be clearly known that the upper floating positioning subassembly 31 is mainly composed of a pressure member 311, a self-locking pressure block 312, an upper spring member 313 and a stop bolt 314. The bottom wall of the upper mold plate 11 extends upward to form an upper installation cavity 111 for inserting the upper spring member 313. The top wall of the upper installation cavity 111 continues to extend upward to form a bolt through hole 112 for the stop bolt 314 to pass freely. The bottom wall of the upper mold core 12 extends upward to form a through-shaped upper sliding cavity 121 for inserting the self-locking pressure block 312 and communicating with the upper plastic-coated sub-cavity 131. The self-locking pressure block 312 is inserted into the upper sliding cavity 121, and its side wall is in contact with the upper mold cavity insert 13. The stop bolt 314 passes through the bolt through hole 112 and the upper mounting cavity 111 in sequence, and is mechanically connected to the self-locking pressure block 312 by means of a threaded pair. The upper spring member 313 is built into the upper mounting cavity 111, and is axially passed through by the stop bolt 314, and its upper and lower end surfaces are elastically pressed against the top wall of the upper mounting cavity 111 and the top wall of the self-locking pressure block 312 in a one-to-one correspondence. The pressure member 311 is used to directly apply a force to the lower floating positioning subassembly 32, and is preferably a round head bolt, and is mechanically connected to the self-locking pressure block 312 by means of a threaded pair.

[0039] Depend on Figure 4 , 5It can also be clearly known that the lower floating positioning subassembly 32 is mainly composed of a horizontal floating sliding member 321, a vertical floating sliding member 322, a lower spring member 323 and a side spring member 324. The top wall of the lower die core 22 extends downward to form a lower special-shaped sliding cavity 221 for simultaneously loading the vertical floating sliding member 322 and the lower spring member 323 and reaching the lower die core 22. The horizontal floating sliding member 321 is formed with an inclined wall sliding notch 3211 for the vertical floating sliding member 322 to freely pass through. The left side wall of the horizontal floating sliding member 321 continues to extend to the left to form an extended push arm 3212. The vertical floating sliding member 322 is beveled, and a sliding guide inclined surface 3221 that matches the inclined wall sliding notch 3211 is formed on its upper end. When the horizontal floating sliding member 321 is assembled relative to the lower mold core 22, the vertical floating sliding member 322 longitudinally passes through the inclined wall sliding notch 3211, the lower spring member 323 is elastically pressed between the lower mold plate 21 and the vertical floating sliding member 322, the side spring member 324 is elastically pressed between the trapezoidal shoulder of the lower mold core 22 and the horizontal floating sliding member 321, and the extended ejection arm 3212 is supported on the top wall of the lower mold cavity insert 23. Under the coordinated action of the lower spring member 323 and the side spring member 324, the sliding guide inclined surface 3221 is able to contact the inclined wall of the inclined wall sliding notch 3211. During the mold closing process, the upper mold assembly 1 performs a displacement movement toward the lower mold assembly 2. The vertical floating sliding member 322 performs a directional downward movement along the lower special-shaped sliding cavity 221 due to the downward pressure from the pressure member 311, and the lower spring member 323 undergoes compression deformation. At the same time, the sliding guide slope 3221 avoids to the left, and the horizontal floating sliding member 321 is able to perform a translational movement to the left under the elastic side thrust from the side spring member 324 until its extended push arm 3212 touches the fork leg, and then the upper mold assembly 1 continues to move downward until the horizontal floating sliding member 321 is tightly pressed by the self-locking pressure block 312, and the planar kinematic freedom of the horizontal floating sliding member 321 is limited to zero.

[0040] After the mold is closed, the relative position of the fork legs in the overmolding cavity is limited, which effectively avoids the relative position change of the fork legs due to the impact force from the high-pressure thermoplastic fluid during the actual overmolding injection molding process. Furthermore, considering that the limiting force acting on the fork legs is an elastic force (the force-applying body is the side spring member 324), and the compression amount of the side spring member 324 can be adaptively changed according to the different impact forces from the high-pressure thermoplastic fluid on the fork legs at different stages, the elastic support force on the fork legs also changes accordingly, and on the premise of ensuring that the fork legs have sufficient impact resistance, the limit is that the fork legs do not undergo elastic deformation. Combining the above factors, on the one hand, the opening size of the fork is accurately controlled after overmolding to ensure that its tolerance value is within the design allowable value range; on the other hand, the overmolding quality is good, which is specifically reflected in: after overmolding, the thickness of the overmolding layer in different areas on the fork legs is basically the same.

[0041] Of course, it should be noted here that, in the process of mold closing, the movable template performs a downward movement, thereby driving the upper mold assembly 1 to perform a displacement movement toward the lower mold assembly 2. At the same time, the upper floating positioning subassembly 31 gradually approaches the lower floating positioning subassembly 32 until the pressure member 311 critically touches the top wall of the vertical floating sliding member. Then, the movable template continues to move downward, and the vertical floating sliding member 322 performs a directional downward movement along the lower special-shaped sliding cavity 221 due to pressure, and the lower spring member 323 is compressed and deformed. At the same time, the sliding The guide slope 3221 evades to the left. Thanks to the inclined design feature of the sliding guide slope 3221, the restriction on the leftward displacement of the horizontal floating sliding member 321 is released. The horizontal floating sliding member 321 is able to perform a translational movement to the left under the elastic side thrust from the side spring member 324 until its extended push arm 3212 touches the fork leg of the shift fork. Then, the upper mold assembly 1 continues to move downward until the horizontal floating sliding member 321 is pressed by the self-locking pressure block 312, and the plane kinematic freedom of the horizontal floating sliding member 321 is limited to zero. As can be seen from the above description, the initial power source for the change in the posture of the lower floating positioning subassembly 32 comes from the injection molding machine, without the need for an independent matching power source. Therefore, under the premise that its floating positioning function is ensured, the shift fork overmolding mold has a very simple design structure, which lays a good foundation for reducing its manufacturing difficulty and manufacturing cost.

[0042] Furthermore, if Figure 4As shown in , the bottom wall of the vertical floating sliding member 322 extends upward to form a vertical insertion hole for the lower spring member 323 to be inserted. The right side wall of the horizontal floating sliding member 321 extends leftward to form a horizontal insertion hole for the side spring member 324 to be inserted. In this way, in the process of the posture change of the lower floating positioning subassembly 32, the lower spring member 323 always occupies the correct installation position relative to the vertical floating sliding member 322, thereby facilitating the vertical floating sliding member 322 to smoothly perform displacement movement along the lower special-shaped sliding cavity 221 under the joint action of the lower spring member 323 and the pressure member 311. At the same time, the side spring member 324 always occupies the correct installation position relative to the horizontal floating sliding member 321, thereby facilitating the fork leg to be stably pushed up by the extended push-up arm 3212.

[0043] In order to ensure that the extended push arm 3212 can be stably pressed against the fork leg and avoid the horizontal floating sliding member 321 from changing its position due to external force or exciting force during the actual overmolding and injection process, when the self-locking pressure block 312 and the horizontal floating sliding member 321 are pressed into contact, the two have a self-locking locking function. The specific means is: the self-locking pressure block 312 is beveled to form an upper self-locking inclined surface 3121 (such as Figure 2 The horizontal floating sliding member 321 is chamfered to form a lower self-locking inclined surface 3213 (as shown in FIG. 1 ) at its upper end portion that matches the upper self-locking inclined surface 3121. Figure 4 ).

[0044] Furthermore, by Figure 4 It can also be clearly seen that the inclination angle between the sliding guide inclined surface 3221 and the horizontal plane is α, and the inclination angle between the lower self-locking inclined surface 3213 and the horizontal plane is β. In order to ensure that the horizontal floating sliding member 321 has excellent translational motion stability during the displacement movement of the vertical floating sliding member 322 along the lower special-shaped sliding cavity 221, α is preferably controlled between 90-110°. In order to ensure that the self-locking pressure block 312 and the horizontal floating sliding member 321 have a stable and reliable self-locking locking function after being pressed, β is preferably controlled between 6-15°.

[0045] Furthermore, if Figure 2 As shown in , the upper floating positioning subassembly 31 is further provided with a stroke adjustment gasket 315. The stroke adjustment gasket 315 is used to limit the lower limit value of the distance d between the head of the stop bolt 314 and the upper mold plate 11, and is sleeved on the stop bolt 314.

[0046] In addition, the present invention also discloses an application method of a shift fork plastic overmolding mold with a floating positioning function, which is implemented by means of the shift fork plastic overmolding mold with a floating positioning function, and includes the following steps: Figure 6As shown in:

[0047] S1, in the mold opening state, the shift fork is placed on the lower mold assembly 2, and its fork foot is positioned opposite to the lower plastic-coated cavity 231;

[0048] S2, start the injection molding machine, the upper mold assembly 1 performs displacement movement toward the lower mold assembly 2, and at the same time, the upper floating positioning subassembly 31 gradually approaches the lower floating positioning subassembly 32 until the pressure member 311 and the vertical floating sliding member 322 are in critical contact (such as Figure 7 );

[0049] S3, the upper mold assembly 1 continues to move downward, the vertical floating sliding member 322 performs a directional downward movement along the lower special-shaped sliding cavity 221 due to the downward pressure from the pressure member 311, and the lower spring member 323 is compressed and deformed. At the same time, the sliding guide inclined surface 3221 moves to the left, and the horizontal floating sliding member 321 is able to perform a translational movement to the left under the elastic side thrust from the side spring member 324 until the extended push arm 3212 touches the fork foot (such as Figure 8 , 9 );

[0050] S4, the upper mold assembly 1 performs downward movement again, and the self-locking pressure block 312 continues to approach the horizontal floating sliding member 321. During this process, the horizontal floating sliding member 321 does not perform translational movement, and its plane kinematic freedom is not restricted (such as Fig.10 );

[0051] S5. The horizontal floating sliding member 321 is pressed against the self-locking pressing block 312, and the planar kinematic freedom of the horizontal floating sliding member 321 is limited to zero. At the same time, the upper mold assembly 1 and the lower mold assembly 2 are closed, the pouring system is formed, and the upper mold-coating sub-cavity 131 and the lower mold-coating sub-cavity 231 are combined to form a mold-coating cavity (such as Fig.11 ).

[0052] Finally, it should be noted that, under the premise of taking into account the high efficiency of the overmolding process and the excellent floating positioning performance of the shift fork, and in order to adapt to the response time of the lower spring member 323 and the side spring member 324, different requirements are made for the upper limit of the downward movement speed of the upper mold assembly 1 at different stages. Specifically, in steps S2, S3, and S4, the upper limits of the downward movement speed of the upper mold assembly 1 are V1, V2, and V3, respectively, and V1, V2, and V3 show an exponentially decreasing law.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A shift fork overmolding mold with floating positioning function, comprising an upper mold assembly and a lower mold assembly; the upper mold assembly and the lower mold assembly respectively correspond to the movable mold plate and the fixed mold plate of the injection molding machine as the installation base; before pre-molding, the upper mold assembly and the lower mold assembly are closed to form a pouring system and an overmolding cavity; after the overmolding is completed, the upper mold assembly and the lower mold assembly are separated to take out the shift fork overmolded part, characterized in that, It also includes a floating positioning assembly; the floating positioning assembly is composed of an upper floating positioning subassembly with the upper mold assembly as an assembly basis and a lower floating positioning subassembly with the lower mold assembly as an assembly basis; in the mold closing process, the upper floating positioning subassembly gradually approaches the lower floating positioning subassembly, and in a subsequent period of time, the lower floating positioning subassembly undergoes a posture change due to the force from the upper floating positioning subassembly, and the fork legs are positioned by the elastic side top force from the lower mold assembly.

2. The fork overmolding mold with floating positioning function according to claim 1, characterized in that: The upper mold assembly includes an upper mold plate, an upper mold core and an upper mold cavity insert; the upper mold core uses the upper mold plate as an installation base; the upper mold cavity insert is embedded in the upper mold core and is flush with the bottom wall of the upper mold core; the lower mold assembly includes a lower mold plate, a lower mold core and a lower mold cavity insert; the lower mold core uses the lower mold plate as an installation base; the lower mold cavity insert is embedded in the lower mold core and is flush with the top wall of the lower mold core; the bottom wall of the upper mold cavity insert is recessed upward to form an upper plastic-coated sub-cavity; the top wall of the lower mold cavity insert is recessed downward to form a lower plastic-coated sub-cavity; Before pre-molding, the upper mold assembly and the lower mold assembly are closed, the upper mold-wrapped sub-cavity and the lower mold-wrapped sub-cavity are combined, and the mold-wrapped cavity is formed.

3. The fork overmolding mold with floating positioning function according to claim 2, characterized in that: The upper floating positioning subassembly includes a pressure piece, a self-locking pressure block, an upper spring piece and a stop bolt; the bottom wall of the upper mold plate extends upward to form an upper mounting cavity for inserting the upper spring piece; the top wall of the upper mounting cavity continues to extend upward to form a bolt through hole for the stop bolt to pass freely; the bottom wall of the upper mold core extends upward to form a through-shaped upper sliding cavity for inserting the self-locking pressure block and communicating with the upper plastic-coated sub-cavity; the self-locking pressure block is inserted into the upper sliding cavity, and its side wall is in contact with the upper mold cavity insert; the stop bolt passes through the bolt through hole and the upper mounting cavity in sequence, and is mechanically connected to the self-locking pressure block by means of a threaded pair; The upper spring member is built into the upper mounting cavity, is axially penetrated by the stop bolt, and its upper and lower end surfaces are elastically pressed against the top wall of the upper mounting cavity and the top wall of the self-locking pressure block respectively and in a one-to-one correspondence; the pressure member is used to directly apply a force to the lower floating positioning subassembly, and it is detachable to achieve fixation with the self-locking pressure block; the lower floating positioning subassembly includes a horizontal floating sliding member, a vertical floating sliding member, a lower spring member and a side spring member; the top wall of the lower die core extends downward to form a lower special-shaped sliding cavity for simultaneously loading the vertical floating sliding member and the lower spring member and reaching the lower die core; the horizontal floating sliding member is formed with a space for the vertical floating sliding member to freely move The cam is provided with a plurality of movable members, each of which is provided with a plurality of movable members, and the movable members are provided with a plurality of movable members, and the movable members are provided with a plurality of movable members. The inclined surface is able to touch the inclined wall of the inclined wall sliding notch; during mold closing, the upper mold assembly performs displacement movement toward the lower mold assembly, and the vertical floating sliding member performs downward movement in a direction along the lower special-shaped sliding cavity due to the downward pressure from the pressure member, and the lower spring member undergoes compression deformation. At the same time, the sliding guide inclined surface avoids to the left, and the horizontal floating sliding member is able to perform translational movement to the left under the elastic side thrust from the side spring member until the extended push arm touches the fork leg, and then the upper mold assembly continues to move downward until the horizontal floating sliding member is tightly pressed by the self-locking pressure block, and the planar kinematic freedom of the horizontal floating sliding member is limited to zero.

4. The fork overmolding mold with floating positioning function according to claim 3, characterized in that: The self-locking pressing block is beveled to form an upper self-locking inclined surface at its lower end; the horizontal floating sliding member is beveled to form a lower self-locking inclined surface at its upper end that matches the upper self-locking inclined surface.

5. The fork overmolding mold with floating positioning function according to claim 4, characterized in that: The inclination angle between the sliding guide inclined surface and the horizontal plane is α, and the inclination angle between the lower self-locking inclined surface and the horizontal plane is β, then 90°≤α≤110°, 6°≤β≤15°.

6. The fork overmolding mold with floating positioning function according to claim 3, characterized in that: The pressure piece is a round head bolt; the pressure piece is mechanically connected with the self-locking pressure block by means of a thread pair.

7. The fork overmolding mold with floating positioning function according to claim 3, characterized in that: The upper floating positioning subassembly also includes a stroke adjustment gasket; the stroke adjustment gasket is used to limit the lower limit value of the distance d between the head of the stop bolt and the upper template, and the stroke adjustment gasket is sleeved on the stop bolt.

8. The application method of the fork plastic overmolding mold with floating positioning function is characterized in that: The method is implemented by using a shift fork overmolding mold with a floating positioning function as described in any one of claims 3 to 7, comprising the following steps: S1, in the mold opening state, placing the shift fork on the lower mold assembly, with its fork foot positioned opposite to the lower plastic-coated cavity; S2, starting the injection molding machine, the upper mold assembly performs displacement movement toward the lower mold assembly, and at the same time, the upper floating positioning subassembly gradually approaches the lower floating positioning subassembly until the pressure member and the vertical floating sliding member are in critical contact; S3, the upper mold assembly continues to perform downward movement, the vertical floating sliding member performs downward movement in a direction along the lower special-shaped sliding cavity due to the downward pressure from the pressure member, the lower spring member undergoes compression deformation, and at the same time, the sliding guide inclined surface avoids to the left, and the horizontal floating sliding member performs translational movement to the left under the elastic side thrust from the side spring member, until the extended push arm touches the fork leg of the shift fork; S4, the upper die assembly performs downward movement again, and the self-locking pressing block continues to approach the horizontal floating sliding member, and in this process, the horizontal floating sliding member does not perform translational movement, and its planar kinematic freedom is not restricted; S5. The horizontal floating sliding member is pressed against by the self-locking pressure block, and the planar kinematic freedom of the horizontal floating sliding member is limited to zero. At the same time, the upper mold assembly and the lower mold assembly are closed, the casting system is formed, and the upper overmolding sub-cavity and the lower overmolding sub-cavity are combined to form an overmolding cavity.

9. The application method of the shift fork overmolding mold with floating positioning function according to claim 8, characterized in that: In steps S2, S3, and S4, the upper limits of the downward movement speed of the upper mold assembly are V1, V2, and V3, respectively, and V1, V2, and V3 show an exponential decreasing law.

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