A novel hot runner cylinder piston

Abstract

This application relates to a novel hot runner cylinder piston, comprising a cylinder, wherein a reciprocating piston is disposed within the inner cavity of the cylinder, and a fixing sleeve and a valve needle are disposed on the side of the piston near the output end of the cylinder; one end of the fixing sleeve is engaged with the piston, and the other end extends out of the cylinder from the output end; the outer side of the fixing sleeve fits against the inner cavity at the output end of the cylinder, and the inner side of the fixing sleeve has a vertically communicating cavity; the assembly end of the valve needle is engaged within the cavity, and the tip of the valve needle penetrates the cavity and extends out of the cylinder. This application solves the problem of easy loosening of the valve needle in existing hot runner cylinder pistons by using a fixing sleeve to engage the valve needle.

Description

Technical Field

[0001] This application relates to the field of hot runner system technology, and in particular to a novel hot runner cylinder piston. Background Technology

[0002] A hot runner cylinder piston is a piston system driven by a cylinder. The piston body is located in the inner cavity of the cylinder, and a valve needle is located at the bottom of the piston. Compressed air drives the piston to reciprocate, which in turn drives the valve needle to move along the axis. Finally, the opening and closing of the gate is controlled by the tip of the valve needle.

[0003] Patent application number CN202010624107.9 discloses a hot runner cylinder air passage system and a hot runner mold. In this system, a valve needle is installed in a groove inside a piston and is secured by a screw threaded to the piston. However, in this design, the piston reciprocates at high speed during use, which can easily loosen the threads securing the valve needle. This can lead to the valve needle becoming loose, losing its fluid-blocking function, causing material leakage, or even nozzle wear.

[0004] Therefore, there is an urgent need for a new type of cylinder piston with a valve needle that is not easily loosened. Utility Model Content

[0005] To address the problem of loose valve needles in existing hot runner cylinder pistons, this application provides a novel hot runner cylinder piston.

[0006] This application provides a novel hot runner cylinder piston, which adopts the following technical solution:

[0007] A novel hot runner cylinder piston includes a cylinder, wherein a reciprocating piston is disposed in the inner cavity of the cylinder, and a fixed sleeve and a valve needle are disposed on the side of the piston near the output end of the cylinder.

[0008] One end of the fixed sleeve is engaged with the piston, and the other end extends out of the cylinder from the output end of the cylinder. The outer side of the fixed sleeve fits into the inner cavity at the output end of the cylinder. The inner side of the fixed sleeve is provided with a cavity that is open at both ends. The assembly end of the valve needle is engaged in the cavity, and the tip of the valve needle passes through the cavity and extends out of the cylinder.

[0009] By adopting the above technical solution, a fixing sleeve is installed at the bottom of the piston through a snap-fit ​​method. The fixing sleeve holds the valve needle in place, thus completing the installation and fixation of the valve needle. In this method, the valve needle is firmly held in place by the fixing sleeve, making it less prone to loosening. One end of the fixing sleeve is snapped onto the piston, and the other end extends from the cylinder outlet. During installation, the fixing sleeve, valve needle, and piston can be assembled first, forming a complete movable assembly that can reciprocate within the cylinder. The entire movable assembly is then installed together within the cylinder. On the other hand, if the valve needle is fixed with threads, the thread height needs to be considered. To make the valve needle more stable, the thread height needs to be sufficiently high, resulting in a higher piston height. However, the technical solution of this application, due to the snap-fit ​​fixing method, eliminates the need for threads on the piston, reducing the requirement for piston height. With the same stroke, the cylinder of this application can have a smaller volume and is more convenient to install.

[0010] Preferably, the piston is provided with a mounting groove on the side near the output end of the cylinder, and a retaining ring hole is provided on the side wall of the mounting groove, and an inner retaining ring is provided in the retaining ring hole;

[0011] The end of the fixed sleeve has an annular retaining block, which is disposed in the mounting groove. One side of the annular retaining block abuts against the bottom surface of the mounting groove, and the other side abuts against the inner retaining ring.

[0012] By adopting the above technical solution, the inner retaining ring locks the annular retaining block around the fixed sleeve. This snap-fit ​​method makes installation quick and convenient.

[0013] Preferably, a first sealing ring is provided between the outer side of the fixed sleeve and the inner sidewall at the output end of the cylinder, and the first sealing ring is provided on the inner sidewall of the cylinder.

[0014] By adopting the above technical solution, the gas in the cylinder cavity is prevented from escaping through the gap between the outer wall of the fixed sleeve and the inner wall of the cylinder through the sealing of the first sealing ring. The sealing ring is set on the inner wall of the cylinder, which ensures that the sealing ring is always in contact with and seals the fixed sleeve when the fixed sleeve moves up and down.

[0015] Preferably, the cavity is provided with a stepped portion, and the assembly end of the valve needle has a convex ring, which is engaged between the piston and the stepped portion.

[0016] By adopting the above technical solution, the valve needle is pressed against the stepped part in the cavity of the fixed sleeve, making the installation of the valve needle quicker and more convenient.

[0017] Preferably, a support block is provided between the convex ring and the piston, the sidewall of the support block is in contact with the inner sidewall of the cavity, and a second sealing ring is provided on the sidewall of the support block.

[0018] By adopting the above technical solution, the support block and the second sealing ring on the support block can seal the cavity inside the fixed sleeve, preventing air in the cylinder from escaping through the cavity inside the fixed sleeve. On the other hand, the support block has a certain thickness, which can compensate for the gap between the valve needle and the piston.

[0019] Preferably, a valve needle support ring is further provided between the support block and the step portion, the height of the valve needle support ring is matched with the height of the convex ring, and the valve needle support ring is arranged around the convex ring.

[0020] By adopting the above technical solution, the height of the valve needle support ring is slightly higher than the height of the convex ring, so that the downward pressure of the support block will not act directly on the valve needle, but on the valve needle support ring. The valve needle can move laterally between the support block and the step. Such translation can offset the dimensional changes of the hot runner system after heating, and prevent the valve needle from being squeezed or stuck.

[0021] Preferably, a support pad is provided between the convex ring and the stepped portion.

[0022] By adopting the above technical solution, the support pad can provide a certain pressure compensation, enhance the force of squeezing the valve needle, and make the overall structure less prone to loosening.

[0023] Preferably, an adjusting screw is provided on the side of the piston away from the output end of the cylinder, and the adjusting screw is threadedly connected to the end of the piston.

[0024] By adopting the above technical solution, the adjusting bolt is screwed into the threaded hole on the top of the piston, which can adjust the height of the adjusting bolt on the top of the piston, thereby adjusting the stroke of the piston reciprocating motion, and the stroke adjustment is convenient.

[0025] Preferably, an adjusting shim is provided between the screw head of the adjusting screw and the piston.

[0026] By adopting the above technical solution, the adjusting shim is set according to the height of the adjusting screw, which can prevent the adjusting bolt from loosening.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. The valve needle is fixed by a retaining sleeve, avoiding the use of threads, making the valve needle less prone to loosening, and the overall height of the piston is smaller;

[0029] 2. An adjusting bolt is provided on the top of the piston, which can be used to change the distance between the highest point on the piston and the top of the cylinder, thereby adjusting the entire piston stroke. Moreover, since the structure at the bottom of the piston occupies less of the piston's height, the adjusting bolt on the top of the piston can be set to be longer, and the adjustment range is larger. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the overall structure in the embodiments of this application (the piston is located at the bottom of the cylinder cavity).

[0031] Figure 2 This is a cross-sectional view of the overall structure in the embodiments of this application (the piston is located at the top of the cylinder cavity).

[0032] Reference numerals: 1. Cylinder; 11. First sealing ring; 2. Piston; 21. Mounting groove; 22. Snap ring hole; 221. Inner snap ring; 3. Valve needle; 31. Protruding ring; 4. Fixing sleeve; 41. Annular retaining block; 42. Stepped part; 5. Support block; 51. Second sealing ring; 6. Valve needle support ring; 7. Support shim; 8. Adjusting screw; 81. Adjusting shim. Detailed Implementation

[0033] The following is in conjunction with the appendix Figure 1 and attached Figure 2 This application will be described in further detail.

[0034] This application discloses a novel hot runner cylinder piston.

[0035] Reference Figure 1 and 2A novel hot runner cylinder piston includes a cylinder 1. The inner cavity of cylinder 1 is wider at the top and narrower at the bottom. The lower part of cylinder 1 is the output end of cylinder 1, and an opening is provided at the lower end of cylinder 1. A piston 2 is disposed in the inner cavity of cylinder 1, and piston 2 can reciprocate up and down in the upper part of cylinder 1. A valve needle 3 is disposed on the side of piston 2 near the opening of cylinder 1. In existing cylinders 1 and pistons 2, valve needle 3 is generally fixed to piston 2 directly or indirectly by threads. For example, in some existing piston 2 cylinders 1, a screw is threaded onto piston 2, and the valve needle 3 is fixed to piston 2 by pressing the screw against it. During long-term use, the threads are prone to loosening, which can lead to loosening of valve needle 3. In the embodiment of this application, a fixing sleeve 4 is provided. The upper end of the fixing sleeve 4 is engaged with the piston 2. While the fixing sleeve 4 is engaged with the piston 2, the assembly end of the valve needle 3 is pressed against the bottom of the piston 2, thus fixing the piston 2. The lower end of the fixing sleeve 4 extends out of the cylinder 1 from the opening of the cylinder 1. The outer side of the lower part of the fixing sleeve 4 is in contact with the inner surface of the lower part of the cylinder 1. A first sealing ring 11 is provided between the fixing sleeve 4 and the inner cavity of the cylinder 1. A sealing ring groove is opened on the inner side wall of the lower part of the cylinder 1. The first sealing ring 11 is placed in the sealing ring groove. The opening of the cylinder 1 is sealed by the first sealing ring 11 to prevent the gas in the cylinder 1 from escaping from the gap between the fixing sleeve 4 and the inner side wall of the cylinder 1. The inner side of the fixed sleeve 4 has a cavity that is open at both ends. The valve needle 3 is disposed in the cavity, and the assembly end of the valve needle 3 is locked between the fixed sleeve 4 and the piston 2. The tip of the valve needle 3 passes through the cavity and extends out of the cylinder 1. In the embodiment of this application, the valve needle 3 is pressed against the bottom of the piston 2 by the fixed sleeve 4, avoiding the use of threads to fix the valve needle 3 and solving the problem that the threads are prone to loosening under long-term operation.

[0036] Reference Figure 1 and 2 The fixed sleeve 4 is fixed to the piston 2 via the mounting groove 21 and the inner retaining ring 221. The mounting groove 21 is located on the side of the piston 2 near the outlet of the cylinder 1. The side wall of the mounting groove 21 is provided with an annular retaining ring hole 22. The inner retaining ring 221 is disposed in the retaining ring hole 22, and the width of the inner retaining ring 221 is greater than that of the retaining ring hole 22. The end of the fixed sleeve 4 has an annular retaining block 41, which is disposed in the mounting groove 21. The upper side of the annular retaining block 41 abuts against the bottom surface of the mounting groove 21, and the lower side abuts against the inner retaining ring 221. The fixed sleeve 4 is pressed tightly against the mounting groove 21 by the inner retaining ring 221. When the piston 2 reciprocates, the inner retaining ring 221 is subjected to the shearing force of the annular retaining block 41. Therefore, the inner retaining ring 221 has sufficient thickness and is made of a material with good shear resistance. When installing the fixing sleeve 4, first place the fixing sleeve 4 into the mounting groove 21, and then install the inner retaining ring 221 to hold the fixing sleeve 4 in place.

[0037] Reference Figure 1 and 2 The mounting end of the valve needle 3 is located in the cavity inside the fixed sleeve 4. The width of the cavity on the side closer to the piston 2 is greater than the width on the side farther from the piston 2. A stepped portion 42 is provided in the cavity. The mounting end of the valve needle 3 has a protruding ring 31, which is engaged between the stepped portion 42 and the piston 2. The stepped portion 42 presses the protruding ring 31 on the valve needle 3 against the bottom of the mounting groove 21, thereby fixing the mounting end of the valve needle 3.

[0038] Reference Figure 1 and 2 A support block 5 is provided between the convex ring 31 and the piston 2. The side wall of the support block 5 fits against the inner side wall of the cavity, and a second sealing ring 51 is provided on the side wall of the support block 5. The second sealing ring 51 seals the cavity of the fixed sleeve 4 to prevent gas in the cylinder 1 from escaping through the cavity inside the fixed sleeve 4. A valve needle support ring 6 is also provided between the support block 5 and the stepped portion 42. The height of the valve needle support ring 6 matches the height of the convex ring 31, and the valve needle support ring 6 is arranged around the convex ring 31. The height of the valve needle support ring 6 is 0.1-0.15mm higher than the height of the convex ring 31 on the valve needle 3. This ensures that the force of pressing the valve needle 3 does not act directly on the valve needle 3; the valve needle 3 can be translated within a certain range. Because the hot runner system has a thermal expansion coefficient, the valve needle 3 needs to be translated within a certain range to absorb the thermal expansion value, so as to avoid the problem of the valve needle 3 getting stuck. A support pad 7 is provided between the convex ring 31 and the stepped portion 42. The convex ring 31 and the valve needle support ring 6 are both pressed on the support pad 7. The support pad 7 can provide a certain pressure compensation and increase the clamping force between the valve needle support ring 6 and the stepped portion 42.

[0039] Reference Figure 1 and 2 A threaded hole is provided on the side of piston 2 away from the output end of cylinder 1, and an adjusting screw 8 is installed in the threaded hole. By rotating the adjusting screw 8, the height of the adjusting screw 8 is adjusted, thereby adjusting the entire stroke of piston 2. Since the lower part of piston 2 is fixed to valve needle 3 by snap-fit ​​in this application, the space occupied by the lower part of piston 2 is small. For a piston 2 of a certain height, the upper part of piston 2 has more space to open the threaded hole. The longer the threaded hole, the larger the adjustment range of adjusting screw 8. In addition, an adjusting shim 81 is provided between the screw head of adjusting screw 8 and piston 2 to prevent adjusting screw 8 from loosening.

[0040] The implementation principle of this application embodiment is as follows: A fixing sleeve 4 is provided on the side of the piston 2 near the outlet of the cylinder 1. The fixing sleeve 4 is snapped onto the piston 2, and at the same time, the mounting end of the valve needle 3 is pressed onto the piston 2. The needle tip of the valve needle 3 extends out from the cavity of the fixing sleeve 4 and extends to the outside of the cylinder 1. In this way, because the valve needle 3 is fixed by snapping, it is not easy to loosen. A first sealing ring 11 and a second sealing ring 51 are respectively provided on the outer and inner sides of the fixing sleeve 4 to seal the entire inner cavity of the cylinder 1. On the other hand, because the valve needle 3 is fixed by snapping, sufficient space is reserved in the upper part of the piston 2, and an adjusting screw 8 can be installed in the upper part of the piston 2. When the piston 2 rises, the screw head of the adjusting screw 8 abuts against the cylinder head of the cylinder 1. Rotating the adjusting screw 8 can adjust the height of the screw head, thereby adjusting the stroke of the piston 2.

[0041] The valve needle 3 of this application is installed as follows: First, the adjusting shim 81 is placed on the step 42 inside the fixed sleeve 4. The valve needle 3 and the valve needle support ring 6 are placed on the adjusting shim 81. Then, the support block 5 with the second sealing ring 51 is pressed on the valve needle 3 and the valve needle support ring 6. Then, the fixed sleeve 4 is placed into the mounting groove 21 as a whole, so that the bottom surface of the mounting groove 21 abuts against the support block 5. Then, the inner retaining ring 221 is installed to lock the fixed sleeve 4 into the mounting groove 21. Finally, the piston 2 is installed in the cylinder 1 to complete the assembly of the entire piston 2.

[0042] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A new hot runner air cylinder piston characterized by: Includes a cylinder (1), in which a reciprocating piston (2) is provided in the inner cavity of the cylinder (1), and a fixed sleeve (4) and a valve needle (3) are provided on the side of the piston (2) near the output end of the cylinder (1); One end of the fixed sleeve (4) is engaged with the piston (2), and the other end extends out of the cylinder (1) from the output end of the cylinder (1). The outer side of the fixed sleeve (4) is fitted with the inner cavity at the output end of the cylinder (1). The inner side of the fixed sleeve (4) is provided with a cavity that is connected vertically. The assembly end of the valve needle (3) is engaged in the cavity, and the tip of the valve needle (3) penetrates the cavity and extends out of the cylinder (1).

2. The novel hot runner cylinder piston according to claim 1, characterized in that: The piston (2) is provided with a mounting groove (21) on the side near the output end of the cylinder (1), and a retaining ring hole (22) is provided on the side wall of the mounting groove (21), and an inner retaining ring (221) is provided in the retaining ring hole (22); The end of the fixed sleeve (4) has an annular locking block (41), which is disposed in the mounting groove (21). One side of the annular locking block (41) abuts against the bottom surface of the mounting groove (21), and the other side abuts against the inner locking ring (221).

3. The novel hot runner cylinder piston according to claim 1, characterized in that: A first sealing ring (11) is provided between the outer side of the fixed sleeve (4) and the inner side wall at the output end of the cylinder (1), and the first sealing ring (11) is provided on the inner side wall of the cylinder (1).

4. A novel hot runner cylinder piston according to claim 1, characterized in that: The cavity is provided with a stepped portion (42), and the assembly end of the valve needle (3) has a convex ring (31), which is engaged between the piston (2) and the stepped portion (42).

5. A novel hot runner cylinder piston according to claim 4, characterized in that: A support block (5) is provided between the convex ring (31) and the piston (2). The side wall of the support block (5) is attached to the inner side wall of the cavity, and a second sealing ring (51) is provided on the side wall of the support block (5).

6. A novel hot runner cylinder piston according to claim 5, characterized in that: A valve needle support ring (6) is also provided between the support block (5) and the step portion (42). The height of the valve needle support ring (6) matches the height of the convex ring (31), and the valve needle support ring (6) is arranged around the convex ring (31).

7. A novel hot runner cylinder piston according to claim 4, characterized in that: A support pad (7) is provided between the convex ring (31) and the stepped portion (42).

8. A novel hot runner cylinder piston according to claim 1, characterized in that: An adjusting screw (8) is provided on the side of the piston (2) away from the output end of the cylinder (1), and the adjusting screw (8) is threadedly connected to the end of the piston (2).

9. A novel hot runner cylinder piston according to claim 8, characterized in that: An adjusting shim (81) is provided between the screw head of the adjusting screw (8) and the piston (2).

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