Driving cylinder and hot runner system

Abstract

The utility model belongs to the technical field of hot runner injection molding, and discloses a driving cylinder and a hot runner system. The driving cylinder comprises a cylinder body and a piston, an inner cavity is formed in the cylinder body, the piston is arranged in the inner cavity in a sliding mode, one end of the piston penetrates out of the cylinder body and can be connected with a valve needle of the hot runner system, a first limiting part is arranged on the outer side wall of the piston, and a second limiting part matched with the first limiting part is arranged on the side wall of the inner cavity. Therefore, the valve needle is prevented from rotating along with the rotation of the piston, so that the injection molding production efficiency is improved, and the risk of equipment damage and the maintenance cost are reduced. The hot runner system comprises a pressure supply device, a valve needle, a hot nozzle glue outlet and the driving cylinder, and the pressure supply device can drive the piston to be slidably arranged in the cylinder body so as to drive the valve needle to open or close the hot nozzle glue outlet. The driving cylinder can prevent the valve needle from rotating, improve the injection molding success rate and the injection molding production efficiency, and reduce the equipment damage risk and the maintenance cost.

Description

Technical Field

[0001] The utility model relates to the technical field of hot runner injection molding, in particular to a driving cylinder and a hot runner system. Background Art

[0002] With the widespread use of plastic products in everyday life and production, their shapes are becoming increasingly diverse. To ensure balanced injection molding, the placement of the inlet port has also become increasingly diverse. In hot runner systems, a valve pin is located within the nozzle cavity, opening and closing the outlet. The pin must be able to move precisely up and down within the nozzle cavity to control the opening and closing of the outlet. Furthermore, when molding products with irregular surfaces, the end face of the hot runner system's valve pin must conform to the non-planar inlet surface of the product, maintaining the same alignment as closely as possible. When encountering large surface differences, the rotation of the valve pin in the hot runner needle valve system can cause numerous problems. From a product quality perspective, valve pin rotation can disrupt the integrity of the surface, resulting in either insufficient or excessive glue. This can further lead to holes and bumps in the product, seriously impacting the product's surface finish quality. Concerning equipment safety and production efficiency, valve pin rotation can damage the hot runner drive mechanism, causing the pin to bend or break. What is more serious is that the mold core may be damaged, which will not only bring great difficulties to maintenance, but also have a great impact on injection molding production and reduce production efficiency.

[0003] In the prior art, in order to prevent the valve needle from rotating, multiple sets of limit surfaces are often set between the hot nozzle and the valve needle. However, the inner wall diameter of the hot nozzle is relatively small, which makes the hot nozzle processing process complicated, increasing production costs and technical difficulties. In addition, this method of setting limit surfaces has problems in actual application. Since the piston of the drive cylinder is connected to the valve needle, when the drive cylinder moves back and forth, the piston may rotate and drive the valve needle to have a rotation trend, which makes it easy to generate large friction between the valve needle and the limit surface, and then cause the valve needle to get stuck, affecting the normal operation of injection molding production, not only reducing production efficiency, but also causing further damage to the equipment and increasing maintenance costs. Utility Model Content

[0004] The first purpose of the present utility model is to provide a drive cylinder to prevent the piston from axially rotating in the cylinder body, thereby preventing the valve needle from rotating due to the rotation of the piston, thereby improving the injection molding production efficiency and reducing the risk of equipment damage and maintenance costs.

[0005] The second object of the present invention is to provide a hot runner system, which, by applying the above-mentioned drive cylinder, prevents the valve needle from rotating, thereby improving the injection molding success rate and injection molding production efficiency, and reducing the risk of equipment damage and maintenance costs.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A drive cylinder is used in a hot runner system. The drive cylinder includes a cylinder body and a piston. An inner cavity is formed inside the cylinder body. The piston is slidably arranged in the inner cavity. One end of the piston passes through the cylinder body and can be connected to the valve needle of the hot runner system. The outer wall of the piston is provided with a first limiting portion, and the side wall of the inner cavity is provided with a second limiting portion that cooperates with the first limiting portion to limit the rotation of the piston in the inner cavity.

[0008] As an optional solution for the driving cylinder, the first limiting portion is a planar limiting outer wall, and the second limiting portion includes a limiting inner wall corresponding to the limiting outer wall.

[0009] As an optional solution for the driving cylinder, one of the first limiting portion and the second limiting portion is configured as a limiting protrusion, and the other is configured as a limiting groove adapted to the limiting protrusion.

[0010] As an optional solution for the driving cylinder, the outer wall of the piston is provided with a plurality of the first limiting portions at intervals along the circumference of the piston, and the side wall of the inner cavity is provided with a plurality of the second limiting portions that cooperate with the first limiting portions.

[0011] As an optional solution for the driving cylinder, the piston includes a piston head and a piston rod connected to the piston head. The diameter of the piston head is larger than the diameter of the piston rod. The piston head is slidably arranged in the inner cavity and the outer side wall is provided with the first limiting portion.

[0012] As an optional solution for the driving cylinder, the cylinder body includes an outlet and an inlet, the piston head separates the inner cavity into a first chamber and a second chamber, the inlet is connected to the first chamber, and the outlet is connected to the second chamber.

[0013] As an optional solution of the driving cylinder, the driving cylinder further includes a cylinder cap arranged in the inner cavity, and the cylinder cap can abut against the piston head to limit the position of the piston.

[0014] As an optional solution for the driving cylinder, the driving cylinder also includes a limit member, which is detachably connected to the cylinder body. The side wall of the inner cavity is provided with a limit boss and a limit groove, and the limit member is partially inserted into the limit groove. The two ends of the cylinder cap along the axial direction of the cylinder body respectively abut against the limit boss and the limit member.

[0015] As an optional solution of the driving cylinder, the driving cylinder includes a connecting piece connected to the cylinder body, a cooling channel is provided inside the connecting piece, and the cooling channel is configured to cool the piston passing through the connecting piece.

[0016] A hot runner system includes a pressure supply device, a valve needle, a hot nozzle glue outlet and the drive cylinder. The pressure supply device can drive the piston to slide in the cylinder body to drive the valve needle to open or close the hot nozzle glue outlet.

[0017] Beneficial effects:

[0018] The utility model provides a drive cylinder for use in a hot runner system. A piston is slidably disposed within the inner cavity of the cylinder body. One end of the piston extends out of the cylinder body and is connected to the valve needle of the runner system. The outer wall of the piston is provided with a first limiting portion, and the inner cavity of the cylinder body is provided with a second limiting portion that cooperates therewith, thereby limiting the axial rotation of the piston and, in turn, the rotation of the valve needle. This avoids quality problems such as glue shortage and excess glue in injection molded products caused by the rotation of the valve needle due to the rotation of the piston, reduces the production of substandard products, makes production smoother, and improves injection molding production efficiency. At the same time, the risk of damage to the hot runner drive device and the mold core due to valve needle rotation is reduced, thereby reducing the frequency and cost of repairs caused by equipment damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional schematic diagram of a driving cylinder provided by an embodiment of the present utility model;

[0020] Figure 2 It is a cross-sectional schematic diagram of a cylinder provided by an embodiment of the present utility model;

[0021] Figure 3 This is a schematic structural diagram of a drive cylinder provided by an embodiment of the present utility model;

[0022] Figure 4 It is a structural schematic diagram of a piston provided in an embodiment of the utility model.

[0023] In the picture:

[0024] 1- cylinder body; 11- inner cavity; 12- limiting inner wall; 13- outlet; 14- inlet; 15- limiting boss; 16- limiting groove;

[0025] 2-piston; 21-piston head; 22-piston rod; 23-limiting outer wall;

[0026] 3-cylinder cap; 4-limiting piece; 5-base; 6-connecting piece. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0028] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0029] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0030] In the description of this embodiment, the terms "upper" and "lower" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive distinction and do not have any special meaning.

[0031] This embodiment provides a hot runner system, which includes a pressure supply device, a valve needle, a hot nozzle glue outlet and a drive cylinder. Figure 1 As shown, the drive cylinder includes a cylinder body 1 and a piston 2. An inner cavity 11 is formed inside the cylinder body 1. The piston 2 is slidably arranged in the inner cavity 11. One end of the piston 2 passes through the cylinder body 1 and can be connected to the valve needle of the hot runner system. The pressure supply device can drive the piston to slide in the cylinder body through gas or hydraulic oil to drive the valve needle to open or close the hot nozzle outlet.

[0032] As the shapes of plastic products become increasingly diverse, different shapes of plastic products have different requirements for glue discharge balance, resulting in a variety of glue inlet position arrangements. When the surface difference is large, the rotation of the valve needle in the hot runner needle valve system will cause problems, such as destroying the integrity of the product plane, resulting in glue shortage or excess glue, forming holes and bulges, affecting the qualified rate of the product appearance, and may also damage the hot runner drive device, crash the mold core, and affect production efficiency. In order to prevent the valve needle from rotating, the existing technology often sets multiple sets of limit surfaces between the hot nozzle and the valve needle. However, the small diameter of the inner wall of the hot nozzle makes the processing process complicated, costly, and difficult. In addition, the drive cylinder piston 2 is connected to the valve needle. When moving back and forth, the piston 2 may drive the valve needle to rotate, generating a large friction force, causing the valve needle to get stuck, affecting production efficiency and possibly damaging the equipment and increasing maintenance costs.

[0033] To solve the above problems, Figure 1 As shown, in the driving cylinder provided in this embodiment, the outer wall of the piston 2 is provided with a first limiting portion, and the side wall of the inner cavity 11 is provided with a second limiting portion that cooperates with the first limiting portion, so as to limit the rotation of the piston 2 in the inner cavity 11, thereby limiting the rotation of the valve needle.

[0034] This drive cylinder prevents quality issues such as missing or excessive glue in injection molded products caused by the rotation of the valve needle, which is driven by the rotation of the piston 2. This reduces the number of defective products, makes production smoother, and improves injection molding efficiency. It also reduces the risk of damage to the hot runner drive unit and the mold core caused by the rotation of the valve needle, reducing the frequency and cost of repairs caused by equipment damage.

[0035] In some embodiments, the first limiting portion is a planar limiting outer wall 23, and the second limiting portion is configured as a limiting inner wall 12 corresponding to the limiting outer wall 23. The planar setting not only effectively limits the axial rotation of the piston 2 in the inner cavity 11, but also has a simple and reliable structure and is easy to process and manufacture. Figures 2 to 4 As shown, the outer wall of the piston 2 is provided with a limiting outer wall 23, and the side wall of the inner cavity 11 is provided with a limiting inner wall 12 that cooperates with the limiting outer wall 23. When the limiting outer wall 23 abuts against the limiting inner wall 12, it can limit the axial rotation of the piston 2 in the inner cavity 11, thereby limiting the rotation of the valve needle.

[0036] In some embodiments, one of the first limiting portion and the second limiting portion is configured as a limiting protrusion, and the other is configured as a limiting groove (not shown) that matches the limiting protrusion. The limiting protrusion can be tightly fitted into the limiting groove, effectively preventing the rotation of the piston 2 in the inner cavity 11, further enhancing the effect of limiting the axial rotation of the piston 2. Optionally, the first limiting portion is configured as a limiting protrusion, and the second limiting portion is configured as a limiting groove that matches the limiting protrusion. Optionally, the first limiting portion is configured as a limiting groove, and the second limiting portion is configured as a limiting protrusion that matches the limiting groove.

[0037] It is worth noting that this embodiment does not impose any specific restrictions on the shape of the limiting protrusion. The two side walls of the limiting protrusion can be set in parallel or at a certain angle, as long as they can cooperate well with the corresponding limiting groove to achieve effective limitation of the axial rotation of the piston 2.

[0038] In this embodiment, the outer wall of the piston 2 is provided with a plurality of first limiting portions at intervals along the circumference of the piston 2. Compared with the case where only one first limiting portion is provided, the configuration of multiple first limiting portions can effectively disperse the force and reduce the pressure concentration, thereby avoiding the situation where the piston 2 is stuck during the reciprocating movement. Such a design makes the piston 2 smoother during the movement, reduces the probability of failure caused by uneven force, and improves the stability and reliability of the entire hot runner system. It is worth noting that there is no specific limitation on the number of the first limiting portions, and it can be two, three or four, etc. It is necessary to ensure that the first limiting portions are evenly distributed along the circumference, and the number of the second limiting portions is set corresponding to the number of the first limiting portions. Specifically, the outer wall of the piston 2 is provided with four first limiting portions at intervals along the axial direction of the piston 2.

[0039] In this embodiment, the piston 2 includes a piston head 21 and a piston rod 22 connected to the piston head 21. The diameter of the piston head 21 is larger than the diameter of the piston rod 22. The piston head 21 is slidably arranged in the inner cavity 11 and the outer wall is provided with a first limiting portion. The diameter of the piston head 21 of the piston 2 is larger than the diameter of the piston rod 22, which enhances stability and sealing performance, and is convenient for setting the first limiting portion, can withstand greater pressure and friction, provide more limiting space, and play a buffering role, providing a strong guarantee for the stable operation of the hot runner system. Specifically, a sealing groove is provided on the side ring of the piston head 21, and a seal (not shown) is installed in the sealing groove to prevent hydraulic oil or gas from leaking from the gap between the piston 2 and the inner cavity 11. When the hydraulic oil or gas acts on the piston 2, the seal can withstand a certain pressure, ensuring that the hydraulic oil or gas can only push the piston 2 to move, and will not leak from the gap between the piston 2 and the cylinder body 1, thereby ensuring the sealing and efficiency of the drive cylinder.

[0040] In this embodiment, the cylinder body 1 includes an outlet 13 and an inlet 14, and the piston head 21 separates the inner cavity 11 into a first chamber and a second chamber. The inlet 14 is connected to the first chamber, and the outlet 13 is connected to the second chamber to realize the reciprocating movement of the piston 2.

[0041] In this embodiment, the drive cylinder further includes a cylinder cap 3 and a retaining member 4. The retaining member 4 is detachably connected to the cylinder body 1. The cylinder cap 3 is disposed within the inner cavity 11 and is fixed in position by the retaining member 4. The cylinder cap 3 abuts against the piston head 21 to limit the position of the piston 2. The cylinder cap 3 prevents the piston 2 from escaping the inner cavity 11. Furthermore, the cylinder cap 3 and the piston head 21 form a first chamber, which cooperates with the second chamber to enable reciprocating motion of the piston. The provision of the retaining member 4 facilitates installation and removal of the piston 2 and cylinder cap 3, and facilitates manufacturing and maintenance.

[0042] Furthermore, the sidewalls of the inner cavity 11 are provided with a limiting boss 15 and a limiting groove 16. The limiting member 4 partially engages in the limiting groove 16, and the two axial ends of the cylinder cap 3 abut against the limiting boss 15 and the limiting member 4, respectively. This provides stable support and fixation for the cylinder cap 3, ensuring that it does not move during operation, thereby stably limiting the position of the piston 2 and improving the operating stability of the entire drive cylinder.

[0043] Among them, the limit groove 16 is an annular groove that runs through the circumference of the inner cavity 11, and the limit member 4 is a circular ring with an opening. During installation, it is necessary to press the limit member 4 to make the opening of the limit member 4 smaller. When the limit member 4 is placed in the position of the limit groove 16, the limit member 4 can restore its original shape under its own elasticity to snap into the limit groove 16, thereby completing the snap-on limit of the cylinder cap 3.

[0044] It is worth noting that there is not only one way to fix the cylinder cap 3 to the cylinder body 1. Optionally, the cylinder cap 3 is fixedly connected to the cylinder body 1 by welding. Optionally, the cylinder cap 3 is fixedly connected to the cylinder body 1 by bolts.

[0045] Furthermore, a base 5 is provided on the end of the stopper 4 away from the cylinder cap 3. This base 5 provides additional support for the stopper 4, making it more stable when restraining the cylinder cap 3 and the piston 2. This further ensures that the cylinder cap 3 does not move during operation, thereby continuously and stably restraining the piston 2 and greatly improving the stability of the entire drive cylinder during operation.

[0046] Specifically, the base 5 is threadedly connected to the cylinder body 1, which can not only ensure the reliability of the connection, but also press against the limiter 4 to ensure the stability of the entire drive cylinder.

[0047] In this embodiment, the drive cylinder includes a connector 6 connected to the cylinder body 1. A cooling channel is provided within the connector 6, configured to cool the piston 2, which passes through the connector 6. Furthermore, the connector 6 isolates the drive cylinder from other components in the hot runner system, preventing heat from being transferred to the cylinder body and effectively preventing overheating from affecting the normal operation of the drive cylinder.

[0048] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A drive cylinder, used in a hot runner system, characterized in that: The driving cylinder comprises a cylinder body (1) and a piston (2), wherein an inner cavity (11) is formed inside the cylinder body (1), and the piston (2) is slidably arranged in the inner cavity (11), and one end of the piston (2) passes through the cylinder body (1) and can be connected to the valve needle of the hot runner system, and the outer wall of the piston (2) is provided with a first limiting portion, and the side wall of the inner cavity (11) is provided with a second limiting portion that cooperates with the first limiting portion to limit the rotation of the piston (2) in the inner cavity (11).

2. The driving cylinder according to claim 1, characterized in that: The first limiting portion includes a planar limiting outer wall (23), and the second limiting portion includes a limiting inner wall (12) matched with the limiting outer wall (23).

3. The driving cylinder according to claim 1, characterized in that: One of the first limiting portion and the second limiting portion is configured as a limiting protrusion, and the other of the first limiting portion and the second limiting portion is configured as a limiting groove matched with the limiting protrusion.

4. The driving cylinder according to claim 1, characterized in that: The outer side wall of the piston (2) is provided with a plurality of first limiting portions spaced apart along the circumference of the piston (2), and the side wall of the inner cavity (11) is provided with a plurality of second limiting portions that cooperate with the first limiting portions.

5. The driving cylinder according to any one of claims 1 to 4, characterized in that: The piston (2) comprises a piston head (21) and a piston rod (22) connected to the piston head (21); the diameter of the piston head (21) is larger than the diameter of the piston rod (22); the piston head (21) is slidably arranged in the inner cavity (11) and the outer side wall is provided with the first limiting portion.

6. The driving cylinder according to claim 5, characterized in that: The cylinder body (1) comprises an outlet (13) and an inlet (14); the piston head (21) separates the inner cavity (11) into a first chamber and a second chamber; the inlet (14) is connected to the first chamber, and the outlet (13) is connected to the second chamber.

7. The driving cylinder according to claim 5, characterized in that: The driving cylinder further comprises a cylinder cap (3) arranged in the inner cavity (11), and the cylinder cap (3) can abut against the piston head (21) to limit the position of the piston (2).

8. The driving cylinder according to claim 7, characterized in that: The driving cylinder further comprises a limiting member (4), the limiting member (4) being detachably connected to the cylinder body (1), the side wall of the inner cavity (11) being provided with a limiting boss (15) and a limiting groove (16), the limiting member (4) being partially inserted into the limiting groove (16), and the cylinder cap (3) being respectively in contact with the limiting boss (15) and the limiting member (4) at both ends along the axial direction of the cylinder body (1).

9. The driving cylinder according to any one of claims 1 to 4, characterized in that: The driving cylinder comprises a connecting piece (6) connected to the cylinder body (1), a cooling channel is provided inside the connecting piece (6), and the cooling channel is configured to cool the piston (2) passing through the connecting piece (6).

10. A hot runner system, characterized in that: It comprises a pressure supply device, a valve needle, a hot nozzle and a drive cylinder as described in any one of claims 1 to 9, wherein the pressure supply device can drive the piston (2) to slide in the cylinder body (1) to drive the valve needle to open or close the glue outlet of the hot nozzle.

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