A valve needle sealing structure for a mold

Abstract

The present invention provides a valve needle sealing structure for a mold, which belongs to the technical field of injection molds. It solves the problem of poor sealing effect of valve needle sealing in existing molds. The valve needle sealing structure of the mold includes a fixed mold, a mounting hole is opened on the fixed mold, a hot nozzle is fixedly inserted in the mounting hole, the valve needle is slidably inserted in the hot nozzle, the sealing structure includes a sealing surface and a pressing surface, a driving part is provided on the fixed mold, the valve needle includes a body and a sealing head, the body and the sealing head are mutually sleeved and can move relatively, an elastic part is provided between the body and the sealing head, the body can rotate circumferentially relative to the fixed mold, and a pushing mechanism is also provided between the fixed mold and the body, which can push the body axially when the pressing surface is pressed on the sealing surface and the body rotates so that the body compresses the elastic part. The valve needle sealing structure of the mold can improve the sealing effect, thereby improving product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molds and relates to a valve needle sealing structure of a mold. Background Art

[0002] Injection molding, also known as injection molding, is a molding method that combines injection and molding. It has fast production speed, high efficiency, and can be automated. It is suitable for mass production and complex-shaped products. At a certain temperature, the completely molten plastic material is stirred by a screw, and then injected into the cavity with high pressure. After cooling and solidification, a molded product is obtained. Therefore, a mounting hole is opened on the fixed mold of the mold. The mounting hole penetrates through one end of the cavity as a gate. A hot nozzle is fixed in the mounting hole. The molten plastic in the injection molding machine is injected into the cavity through the hot nozzle. Since the pressure in the cavity increases when the molten plastic is injected into the cavity, a valve needle is also slidably penetrated in the hot nozzle. The valve needle is driven to retract by a cylinder. After the injection is completed, the cylinder drives the valve needle to insert into the gate for sealing to achieve sealing. In order to improve the effect of sealing, a sealing surface is set on the inner wall of the gate, and the valve needle is sealed by fitting and pressing with the sealing surface.

[0003] For example, the single-point valve needle hot nozzle disclosed in the patent document (application number: 200920261856.9) includes a hot runner and a cylinder. The hot runner includes a hot runner body, a hot nozzle tip and a sealing ring. The sealing ring is sleeved on the hot nozzle tip and fixed with the hot runner body. The cylinder includes a cylinder body and a piston matched with the cylinder body. The piston is fixed with one end of the valve needle. The valve needle passes through the main flow channel and matches with the hot nozzle tip. The end of the valve needle has a conical pressing surface, and the hot nozzle tip has a conical sealing surface. The two are pressed together to form a seal. However, the molten plastic in the mold cavity will change from injection to solidification, which causes the pressure in the mold cavity to change. In particular, when the material in the mold cavity changes from a high elastic state to a glass state, the pressure in the mold cavity will increase. At this time, if the pressure of the cylinder is difficult to meet the sealing requirements when the pressure in the mold cavity increases, the material in the mold cavity will squeeze between the pressing surface and the sealing surface, resulting in flash on the product, affecting product quality. However, if a cylinder with a larger air pressure value is directly used to meet the demand when the pressure in the cavity increases, the sealing surface will need to withstand a larger clamping force during the entire process of product curing and molding. This will cause the solid part of the fixed mold sealing surface to appear concave and deform into the cavity, which will also affect the product quality. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and to propose a valve needle sealing structure for a mold. The valve needle sealing structure for the mold can improve the sealing effect and thus improve the product quality.

[0005] The object of the present invention can be achieved through the following technical solutions: a valve needle sealing structure of a mold, the mold includes a fixed mold with a cavity surface, the fixed mold is provided with a mounting hole that penetrates through the cavity surface, a hot nozzle is fixedly inserted in the mounting hole, and the valve needle is slidably inserted in the hot nozzle, the sealing structure includes an annular sealing surface located on the inner wall of the mounting hole and close to the cavity surface and an annular pressing surface located at the inner end of the valve needle, the fixed mold is provided with a driving member that can drive the valve needle to extend out of the hot nozzle and make the pressing surface fit and press on the sealing surface, characterized in that the valve needle includes a rod-shaped body and a sealing head with the above-mentioned pressing surface, the body and the sealing head are mutually sleeved and can move relatively, an elastic member is provided between the body and the sealing head, the body can rotate circumferentially relative to the fixed mold, and a pushing mechanism is also provided between the fixed mold and the body, which can push the body axially when the pressing surface is pressed on the sealing surface and the body rotates so that the body compresses the elastic member.

[0006] When the fixed mold and the movable mold are closed, the cavity surface on the fixed mold and the cavity surface on the movable mold are closed together to form a cavity. The outer end of the hot nozzle is connected to the injection molding machine, and the inner end is connected to the cavity. The valve needle is inserted into the hot nozzle and controls the hot nozzle to be turned on and off by axial sliding. During injection molding, the fixed mold and the movable mold are closed, and the valve needle moves outward to connect the hot nozzle with the cavity. The injection molding machine injects molten plastic into the cavity through the hot nozzle. After the injection is completed, the driving part drives the valve needle to move toward the cavity until the pressing surface is pressed against the sealing surface, and there is a set pressing force between the two to prevent the molten plastic in the cavity from being squeezed into the space between the pressing surface and the sealing surface due to internal pressure to form flash. Subsequently, the molten plastic in the cavity gradually solidifies, and the material in the cavity undergoes a gradual transition from a highly elastic state to a glassy state. During this transition, the pressure in the cavity increases. For this reason, the present application configures the valve needle as a body, a sealing head, and an elastic member. The elastic force of the elastic member is greater than the driving force of the driving member, and the body can rotate circumferentially. When the material in the cavity is about to enter the transition process from a highly elastic state to a glassy state, the body rotates circumferentially, and the pushing mechanism can push the body toward the cavity. The body can compress the elastic member, and the elastic member generates an elastic thrust on the sealing head. The elastic thrust is greater than the driving thrust applied to the body by the driving member. This increases the clamping force between the clamping surface and the sealing surface, improves the sealing effect, and prevents the material in the cavity from being squeezed into the space between the clamping surface and the sealing surface during the transition from the highly elastic state to the glassy state to form flash, thereby improving product quality. Furthermore, since the elastic thrust of the elastic member is only applied to the sealing head during the transition from the highly elastic state to the glassy state, and in other molding stages where the pressure in the cavity is relatively small, the sealing head is only sealed by the driving force of the driving member, thereby preventing the sealing surface of the fixed mold from being deformed into the cavity due to a long period of high clamping force, thereby improving product quality.

[0007] In the valve needle sealing structure of the above-mentioned mold, the mounting hole includes a mounting section and a glue injection section, one end of the glue injection section is connected to the mounting section, and the other end penetrates to the cavity surface, the inner circumferential surface of the glue injection section is the above-mentioned glue sealing surface, and the glue sealing surface is a conical surface with the small end facing the cavity surface, the hot nozzle is fixed in the mounting section, and the outlet of the hot nozzle is relatively connected to the end with a larger aperture of the glue injection section, the clamping surface is a conical surface with the small end facing the cavity surface, and can be inserted into the glue injection section when the glue sealing head extends out of the hot nozzle. The mounting section is used to accommodate and install the hot nozzle, the glue sealing section is used to connect the hot nozzle and the air cavity, and is used for the valve needle to be inserted during glue sealing, and the clamping surface circumferentially arranged at the end of the valve needle can be pressed against the glue sealing surface of the glue sealing section, and the pressing fit of the two conical surfaces has a large pressing force, which improves the glue sealing effect.

[0008] In the valve needle sealing structure of the above-mentioned mold, a connecting hole is axially opened on one end face of the body facing the cavity surface, the sealing head is columnar, and has a columnar connecting part on one end face of the sealing head facing the body, a connecting groove is circumferentially opened on the outer circumference of the connecting part, a retaining spring is circumferentially fixed on the hole wall of the connecting hole, the connecting part is slidably inserted in the connecting hole, and the inner edge of the retaining spring is embedded in the connecting groove. The connecting part of the sealing head is inserted in the connecting hole of the body and axially limited by the retaining spring, the axial width of the connecting groove is greater than the thickness of the retaining spring, so that the retaining spring can slide in the connecting groove, that is, the sealing head can move axially relative to the body.

[0009] In the above-mentioned valve needle sealing structure of the mold, the elastic member includes a butterfly spring arranged in the connecting hole, one end of the butterfly spring abuts against the bottom surface of the connecting hole, and the other end abuts against the end surface of the connecting part, and under the action of the butterfly spring, the clamping spring abuts against the groove wall of the connecting groove away from the sealing head, so that the butterfly spring maintains a stable position and the sealing head is also in a stable state.

[0010] In the valve needle sealing structure of the above-mentioned mold, the outer peripheral surface of the connecting part is slidably matched with the wall of the connecting hole, and an elastic ring made of polyurethane material is also sleeved on the connecting part, and the end faces of the elastic ring are respectively against the end faces of the body and the end faces of the sealing head. The space between the inner peripheral surface of the hot nozzle and the outer peripheral surface of the valve needle is used for the molten plastic to pass through. The elastic ring can prevent the molten plastic from remaining between the end faces of the body and the end faces of the sealing head, and form a seal between the two to prevent the molten plastic from penetrating into the connecting hole. At the same time, the elastic ring makes the sealing head and the body in a tensioned state to prevent the sealing head from moving when the valve needle moves, and to provide buffering when the pressing surface and the sealing surface are in contact. When the body rotates circumferentially, the elastic ring can also generate an axial elastic thrust on the sealing head to improve the sealing effect.

[0011] In the valve needle sealing structure of the above-mentioned mold, the driving part includes a cylinder fixed on the fixed mold, the piston rod end of the cylinder is fixed with a connecting block, a clearance hole is opened on the end face of the connecting block, the hole wall of the clearance hole has an annular limiting convex edge in the circumferential direction, the outer end of the body is slidably inserted in the clearance hole, and a limiting pin is radially penetrated at the end of the body inserted into the clearance hole, and the two ends of the limiting pin extend out of the outer circumferential surface of the body and are located between the bottom surface of the clearance hole and the limiting convex edge. After the end of the body is inserted into the clearance hole, the limiting pin is used to limit the axial position, and the body can rotate relative to the connecting block, that is, during injection molding, the connecting block drives the limiting pin through the limiting convex edge, so that the body moves away from the cavity, and during sealing, the connecting block pushes the end face of the body through the bottom surface of the clearance hole, and the body can move axially relative to the connecting block when the pushing mechanism pushes the body.

[0012] In the valve needle sealing structure of the above-mentioned mold, the pushing mechanism includes two brackets fixed on the fixed mold and symmetrically arranged on both sides of the main body, and the brackets are rotatably connected with balls protruding downward. The outer circumferential surface of the main body is provided with two radially protruding pushing parts, and the two pushing parts are symmetrically arranged. The upper end surfaces of the pushing parts are provided with pushing inclined surfaces, and one end of the pushing inclined surface along the circumference of the main body is lower than the other end. When the main body rotates circumferentially, the lower end of the pushing inclined surface moves to below the ball, and the ball can rest on the pushing inclined surface. When the driving member drives the main body to descend so that the pressing surface is pressed against the sealing surface, the pushing portion can descend from the side of the bracket and be lower than the ball. When the pressing surface is against the sealing surface and the main body rotates, the pushing portion can gradually move under the ball. The ball presses on the pushing inclined surface and gradually rolls from the lower end of the pushing inclined surface to the higher end. Therefore, the main body can be pushed downward and compress the elastic member. The elastic member generates a downward elastic thrust on the sealing column, thereby increasing the pressing force between the pressing surface and the sealing surface.

[0013] In the valve needle sealing structure of the above-mentioned mold, the upper end surface of the push portion has a push convex edge protruding upward, the push inclined surface is the upper side surface of the push convex edge, the upper end of the bracket has a mounting portion protruding toward the valve needle, the mounting portion is provided with a spherical groove, and the ball is arranged in the spherical groove. The lower part of the ball protrudes from the spherical groove and can abut against the push inclined surface of the push convex edge.

[0014] In the valve needle sealing structure of the above-mentioned mold, a driven pulley is rotatably connected to the fixed mold, the body passes through the driven pulley, and the body and the driven pulley are circumferentially positioned by spline cooperation, and a motor is also fixed to the fixed mold, and a driving pulley is fixed on the motor shaft of the motor, and the driving pulley is connected to the driven pulley by belt transmission. The driven pulley and the body are splined, so the body can slide axially relative to the driven pulley, but the two are circumferentially positioned so that the motor can drive the body to rotate circumferentially through the driven pulley.

[0015] In the above-mentioned valve needle sealing structure of the mold, the fixed mold has an annular connecting convex edge on the circumference, and the driven pulley is rotatably sleeved on the connecting convex edge through a bearing, so that the driven pulley structure is more stable.

[0016] Compared with the prior art, the valve needle sealing structure of this mold has the following advantages:

[0017] 1. As the material in the cavity changes from a highly elastic state to a glassy state, the body rotates circumferentially, and the pushing mechanism can push the body toward the cavity. The body can compress the elastic part, and the elastic part generates an elastic thrust on the sealing head, thereby increasing the pressing force between the pressing surface and the sealing surface, improving the sealing effect, and preventing the material in the cavity from squeezing into the space between the pressing surface and the sealing surface to form flash, thereby improving product quality.

[0018] 2. Since the elastic thrust of the elastic part is only applied to the sealing head during the transition from the highly elastic state to the glass state, and in the other molding stages where the pressure in the cavity is relatively small, the sealing head is only sealed by the driving force of the driving part, thereby avoiding the sealing surface of the fixed mold from being deformed into the cavity due to long-term large pressing force, thereby improving product quality.

[0019] 3. Since an elastic ring made of polyurethane material is sleeved on the connection part, the elastic ring can prevent molten plastic from remaining between the end face of the main body and the end face of the sealing head, and form a seal between the two, preventing molten plastic from penetrating into the connection hole, and providing buffering when the pressing surface and the sealing surface are in contact. When the main body rotates circumferentially, the elastic ring can also generate axial elastic thrust on the sealing head, thereby improving the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a partial structural cross-sectional view of the valve needle sealing structure of the mold.

[0021] Figure 2 yes Figure 1 A magnified view of the structure at center.

[0022] Figure 3 yes Figure 1 A magnified view of the structure at point B.

[0023] Figure 4 It is a structural diagram of the push mechanism.

[0024] In the figure, 1, fixed mold; 11, cavity surface; 12, cavity; 13, mounting hole; 131, mounting section; 132, injection section; 133, sealing surface; 14, connecting convex edge; 2, movable mold; 3, hot nozzle; 4, valve needle; 41, body; 411, connecting hole; 412, retaining ring; 413, limit pin; 414, spline; 42, sealing head; 421, pressing surface; 422, connecting part; 423, connecting groove; 43, elastic ring ; 5. Driving member; 51. Cylinder; 6. Connecting block; 61. Clearance hole; 62. Limiting convex edge; 7. Elastic member; 8. Pushing mechanism; 81. Pushing part; 82. Pushing convex edge; 821. Pushing inclined surface; 83. Bracket; 831. Mounting part; 832. Spherical groove; 84. Ball; 9. Motor; 91. Driving pulley; 92. Driven pulley; 921. Connecting sleeve; 922. Keyway; 93. Belt; 94. Bearing. DETAILED DESCRIPTION

[0025] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0026] like Figure 1 , Figure 2 As shown, a valve needle sealing structure of a mold, the mold includes a fixed mold 1 and a movable mold 2, both of which have a cavity surface 11. When the fixed mold 1 and the movable mold 2 are molded together, the cavity surface 11 on the fixed mold 1 and the cavity surface 11 on the movable mold 2 are combined to form a cavity 12. A mounting hole 13 penetrating to the cavity surface 11 is opened on the fixed mold 1, and the mounting hole 13 includes a mounting section 131 and a glue injection section 132. One end of the glue injection section 132 is connected to the mounting section 131, and the other end penetrates the cavity surface 11. A hot nozzle 3 is fixedly inserted in the mounting section 131 of the mounting hole 13, and the outer end of the hot nozzle 3 is connected to the injection molding machine. The inner circumference of the glue injection section 132 is an annular sealing surface 133, and the sealing surface 133 is a conical surface with the small end facing the cavity surface 11. The outlet of the hot nozzle 3 is relatively connected to the end of the glue injection section 132 with a larger aperture. The valve needle 4 is slidably arranged in the hot nozzle 3. The valve needle 4 includes a rod-shaped body 41 and a sealing head 42. The body 41 and the sealing head 42 are mutually sleeved and can move relatively. An elastic member 7 is arranged between the body 41 and the sealing head 42. The sealing head 42 has a pressing surface 421 in the circumferential direction at one end facing the cavity 12. The pressing surface 421 is a conical surface with a small end facing the cavity 12 and adapted to the sealing surface 133. A driving member 5 is arranged on the fixed mold 1. The driving member 5 can drive the valve needle 4 to move axially, so that the sealing head 42 extends out of the hot nozzle 3 and the pressing surface 421 is pressed against the sealing surface 133. The body 41 can rotate circumferentially relative to the fixed mold 1. A pushing mechanism 8 is also arranged between the fixed mold 1 and the body 41. When the pressing surface 421 is pressed against the sealing surface 133 and the body 41 rotates, the pushing mechanism 8 can push the body 41 axially so that the body 41 compresses the elastic member 7.

[0027] Specifically, a connecting hole 411 is axially opened on one end face of the body 41 facing the cavity surface 11, the sealing head 42 is columnar, and has a columnar connecting portion 422 on one end face of the sealing head 42 facing the body 41, a connecting groove 423 is circumferentially opened on the outer circumference of the connecting portion 422, a retaining spring 412 is circumferentially fixed on the hole wall of the connecting hole 411, the connecting portion 422 is slidably inserted in the connecting hole 411, and the outer circumference of the connecting portion 422 is slidably matched with the hole wall of the connecting hole 411, and the inner edge of the retaining spring 412 is embedded in the connecting groove 423. The elastic member 7 includes a butterfly spring arranged in the connecting hole 411, one end of the butterfly spring abuts against the bottom surface of the connecting hole 411, and the other end abuts against the end face of the connecting portion 422, and under the action of the butterfly spring, the retaining spring 412 abuts against the groove wall of the connecting groove 423 away from the sealing head 42. An elastic ring 43 made of polyurethane material is also sleeved on the connecting portion 422, and the end faces of the elastic ring 43 are respectively against the end faces of the body 41 and the end faces of the sealing head 42. In the above-mentioned valve needle 4 sealing structure of the mold, the driving member 5 includes a cylinder 51 fixed on the fixed mold 1, and a connecting block 6 is fixed to the piston rod end of the cylinder 51. A clearance hole 61 is opened on the end face of the connecting block 6, and the hole wall of the clearance hole 61 has an annular limiting convex edge 62 in the circumferential direction. The outer end of the body 41 is slidably inserted into the clearance hole 61, and a limiting pin 413 is radially penetrated at the end of the body 41 inserted into the clearance hole 61. The two ends of the limiting pin 413 extend out of the outer circumferential surface of the body 41 and are located between the bottom surface of the clearance hole 61 and the limiting convex edge 62.

[0028] Combination Figure 3 As shown, the fixed mold 1 has an annular connecting flange 14 on the circumference, and the connecting flange 14 is rotatably connected to the driven pulley 92 through a bearing 94. The body 41 passes through the driven pulley 92, and a spline 414 is provided on the outer wall of the body 41. The driven pulley 92 has an upwardly protruding connecting sleeve 921 on the upper side surface, and the connecting sleeve 921 has a keyway 922 on the inner wall that penetrates to the lower side surface of the driven pulley 92. The spline 414 is slidably embedded in the keyway 922. The fixed mold 1 is also fixed with a motor 9, and a driving pulley 91 is fixed on the motor shaft of the motor 9. The driving pulley 91 is connected to the driven pulley 92 through a belt 93. Figure 4As shown, the pushing mechanism 8 includes two brackets 83 fixed on the fixed mold 1 and symmetrically arranged on both sides of the body 41, the upper ends of the brackets 83 have mounting portions 831 protruding toward the body 41, the mounting portions 831 are provided with spherical grooves 832, and balls 84 are arranged in the spherical grooves 832, and the lower part of the balls 84 protrudes downward from the spherical grooves 832, and the outer peripheral surface of the body 41 has two radially protruding pushing portions 81, the two pushing portions 81 are symmetrically arranged, and the upper end surfaces of the pushing portions 81 have upwardly protruding pushing convex edges 82, and the upper end surfaces of the pushing convex edges 82 are provided with pushing inclined surfaces 821, and one end of the pushing inclined surfaces 821 along the circumference of the body 41 is lower than the other end, when the pressing surface 421 is in contact with the sealing surface 133 and the body 41 rotates circumferentially, the lower end of the pushing inclined surfaces 821 moves to below the balls 84, and the balls 84 can rest against the pushing inclined surfaces 821.

[0029] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0030] Although the terminology such as fixed mold 1, cavity surface 11, cavity 12 is used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A valve needle sealing structure of a mold, the mold comprising a fixed mold (1) having a cavity surface (11), the fixed mold (1) being provided with a mounting hole (13) penetrating to the cavity surface (11), a hot nozzle (3) being fixedly inserted in the mounting hole (13), a valve needle (4) being slidably inserted in the hot nozzle (3), the sealing structure comprising an annular sealing surface (133) located on the inner wall of the mounting hole (13) and close to the cavity surface (11) and an annular pressing surface (421) located at the inner end of the valve needle (4), the fixed mold (1) being provided with a driving member (5) capable of driving the valve needle (4) to extend out of the hot nozzle (3) and making the pressing surface (421) fit and press against the sealing surface (133), characterized in that: The valve needle (4) comprises a rod-shaped body (41) and a sealing head (42) having the above-mentioned pressing surface (421); the body (41) and the sealing head (42) are sleeved with each other and can move relative to each other; an elastic member (7) is provided between the body (41) and the sealing head (42); the body (41) can rotate circumferentially relative to the fixed mold (1); and a pushing mechanism (8) is also provided between the fixed mold (1) and the body (41) so that when the pressing surface (421) is pressed against the sealing surface (133) and the body (41) rotates, the body (41) can be pushed axially so that the body (41) compresses the elastic member (7);A connecting hole (411) is axially provided on an end surface of the body (41) facing the cavity surface (11); the sealing head (42) is columnar, and has a columnar connecting portion (422) on an end surface of the sealing head (42) facing the body (41); a connecting groove (423) is circumferentially provided on an outer circumferential surface of the connecting portion (422); a retaining spring (412) is circumferentially fixed on a hole wall of the connecting hole (411); the connecting portion (422) is slidably inserted into the connecting hole (411), and an inner edge of the retaining spring (412) is embedded in the connecting groove (423); the elastic member (7) comprises a butterfly spring arranged in the connecting hole (411); one side of the butterfly spring is provided with a butterfly spring. One end of the bracket (83) abuts against the bottom surface of the connecting hole (411), and the other end abuts against the end surface of the connecting portion (422). Under the action of the butterfly spring, the retaining ring (412) abuts against the groove wall of the connecting groove (423) away from the sealing head (42). The pushing mechanism (8) includes two brackets (83) fixed on the fixed mold (1) and symmetrically arranged on both sides of the body (41). The brackets (83) are rotatably connected to balls (84) protruding downward. The outer peripheral surface of the body (41) has two radially protruding pushing portions (81). The two pushing portions (81) are symmetrically arranged. The upper end surface of the pushing portion (81) has a pushing inclined surface (821), and the pushing inclined surface (82 1) One end along the circumference of the body (41) is lower than the other end; when the pressing surface (421) is pressed against the sealing surface (133) and the body (41) rotates circumferentially, the lower end of the push inclined surface (821) moves below the ball (84), and the ball (84) can be pressed against the push inclined surface (821); the upper end surface of the push portion (81) is provided with a push convex edge (82) protruding upward; the push inclined surface (821) is the upper side surface of the push convex edge (82); the upper end of the bracket (83) is provided with a mounting portion (831) protruding toward the valve needle (4); the mounting portion (831) is provided with a spherical groove (832); the ball (84) is provided with a spherical groove (832); ) is arranged in the spherical groove (832), a driven pulley (92) is rotatably connected to the fixed mold (1), the body (41) passes through the driven pulley (92), and the body (41) and the driven pulley (92) are circumferentially positioned by splines (414), a motor (9) is also fixed to the fixed mold (1), a driving pulley (91) is fixed to the motor (9) shaft of the motor (9), the driving pulley (91) and the driven pulley (92) are connected by a belt (93), and an annular connecting convex edge (14) is circumferentially provided on the fixed mold (1), and the driven pulley (92) is rotatably sleeved on the connecting convex edge (14) through a bearing (94). ; 2. The valve needle sealing structure of the mold according to claim 1, characterized in that: The mounting hole (13) comprises a mounting section (131) and a glue injection section (132); one end of the glue injection section (132) is in communication with the mounting section (131), and the other end thereof penetrates through the cavity surface (11); the inner circumferential surface of the glue injection section (132) is the aforementioned glue sealing surface (133); the glue sealing surface (133) is a conical surface with a small end facing the cavity surface (11); the hot nozzle (3) is fixed in the mounting section (131), and the outlet of the hot nozzle (3) is in communication with an end of the glue injection section (132) with a larger aperture; the pressing surface (421) is a conical surface with a small end facing the cavity surface (11), and can be inserted into the glue injection section (132) when the glue sealing head (42) extends out of the hot nozzle (3).

3. The valve needle sealing structure of the mold according to claim 2, characterized in that: The outer peripheral surface of the connecting portion (422) is slidably matched with the wall of the connecting hole (411), and an elastic ring (43) made of polyurethane material is also sleeved on the connecting portion (422), and the end surfaces of both ends of the elastic ring (43) are respectively in contact with the end surface of the body (41) and the end surface of the sealing head (42).

4. The valve needle sealing structure of the mold according to any one of claims 1 to 3, characterized in that: The driving member (5) comprises a cylinder (51) fixed on the fixed mold (1), a connecting block (6) being fixed at the end of the piston rod of the cylinder (51), a clearance hole (61) being opened on the end surface of the connecting block (6), a hole wall of the clearance hole (61) having an annular limiting convex edge (62) in the circumferential direction, an outer end of the body (41) being slidably inserted into the clearance hole (61), and a limiting pin (413) being radially penetrated at the end of the body (41) inserted into the clearance hole (61), two ends of the limiting pin (413) extending out of the outer circumferential surface of the body (41) and being located between the bottom surface of the clearance hole (61) and the limiting convex edge (62).

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