Sealing device for coating needle of spray gun

Abstract

The utility model provides a sealing device for a coating needle of a spray gun, which comprises a sealing element 6 for sealing the coating needle 3 in the circumferential direction and a hollow bolt 7 for accommodating the sealing element 6, and is characterized in that the sealing element 6 comprises a self-compensating structure 61 positioned at the inner side end of the hollow bolt 7, and the self-compensating structure 61 comprises a circumferential slotted hole 611, a longitudinal slotted hole 612 and a longitudinal slotted hole 614, a self-compensation section 612 is arranged on one side, close to the coating needle 3, of the circumferential slotted hole 611; and the elastic piece 62 is positioned in the circumferential slotted hole 611 and is used for supporting the self-compensating section 612. The sealing element 6 is provided with a self-compensating structure 61, so that the coating needle 3 can be well sealed, and the back-and-forth movement smoothness of the coating needle 3 can be ensured; meanwhile, continuous compensation can be generated, and the wear-resistant life is prolonged to more than 12 months; and the sealing element 6 is of an integrated structure, so that the coaxiality is better. Mass production of the sealing element 6 can be achieved through a special mold, the difficulty of part machining is lowered, and the efficiency of mass production is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of spray guns and relates to a sealing device for a paint needle of a spray gun. Background Art

[0002] A paint spray gun (hereinafter referred to as a spray gun) is a common spraying tool. Due to different principles, common types include electrostatic paint spray guns, airless paint spray guns, and pneumatic paint spray guns. Here, the pneumatic paint spray gun is taken as an example for introduction. Its working principle is to convert liquid paint into atomized particles by using compressed air.

[0003] The sealing parts of the spray gun play a very important role among the parts of the spray gun: one is to prevent the paint in the paint passage of the spray gun from leaking, and the other is to prevent the compressed air in the air passage inside the spray gun from leaking.

[0004] Because the spray gun itself needs to be used together with corrosive paint and needs to be cleaned with a thinner (such as turpentine) after use, the sealing parts must have the following characteristics: 1. Anti-corrosion; 2. Wear resistance; 3. At the same time, it is necessary to ensure the smooth movement of parts such as the paint needle 3 and the valve needle.

[0005] The existing spray gun mainly consists of a spray gun body 1, an atomization component, a pressing and sealing component 2, a paint needle 3, a return spring 4, a trigger 5, a gas valve component and other parts. See Figure 1 -3.

[0006] As Figure 1 shown, the spray gun includes a spray gun body 1. A head paint bin 11 for containing paint, a head paint needle small hole 12 for containing the paint needle 3, and a head sealing component hole 13 for containing the pressing and sealing component 2 are provided at the head of the spray gun.

[0007] As Figure 2 shown, the movement of the paint needle 3 is controlled by the trigger 5, the paint needle 3 is reset by the return spring 4, the pressing and sealing component 2 and its external mating bolt 23 are fixedly arranged in the head sealing component hole 13 in cooperation, and the sealing component 2 and the bottom sealing piece 21 cooperate to complete the sealing of the paint needle 3.

[0008] As Figure 3As shown in the figure, the existing sealing structure includes a mating bolt 23, which is externally provided with threads to cooperate with the hole 13 of the head pressing and sealing component for fixation. A bottom sealing member 21 is provided at the end of the mating bolt 23. The bottom sealing member 21 is engaged with the mating bolt 23 through a card slot to seal the end of the coating needle 3. A pressing and sealing component 2 is arranged inside the mating bolt 23 close to the bottom sealing member 21. The end of the pressing and sealing component 2 is in wedge-shaped contact with the bottom sealing member 21. A pressing spring 22 is arranged behind the pressing and sealing component 2. In this way, the elastic force of the pressing spring 22 makes the pressing and sealing component 2 and the bottom sealing member 21 in wedge-shaped contact to radially hold and compensate the coating needle 3. However, this holding force is limited by the free movement of the coating needle 3, and this self-compensation is limited and the effect is not obvious.

[0009] Although the existing sealing structure uses anti-corrosion and wear-resistant materials, in actual use, the following problems still exist:

[0010] 1. The rebound movement of the coating needle 3 completely depends on the return spring 4 of the coating needle 3. If the inner diameter of the pressing and sealing component 2 is 0.02 mm or more smaller than the designed size, it will cause the holding force to be too large to lock the coating needle 3, resulting in needle jamming or slow rebound, and thus the coating will directly leak from the nozzle. If the inner diameter of the pressing and sealing component 2 is 0.02 mm or more larger than the designed size, it will cause the holding force to be too small, and the coating will leak from the gap between the coating needle 3 and the sealing point.

[0011] 2. During batch processing, the inner diameter dimension tolerance accuracy of the pressing and sealing component 2 needs to be controlled within 0.02 mm to meet the requirements of sealing and smooth movement of the coating needle 3. This is quite difficult in the manufacturing process. Even if the tolerance accuracy of the inner diameter dimension is ensured, the production efficiency is low. In addition, since the pressing and sealing component 2 itself is made of plastic material, its inner diameter dimension changes due to the influence of thermal expansion and contraction, resulting in the pressing and sealing component 2 always being the part of the spray gun that is most prone to failure.

[0012] 3. When the spray gun is working, the coating needle 3 makes continuous reciprocating movements, and the wear on the sealing point is also relatively large. Without self-compensation, the sealing point will be completely worn out after 2 - 4 months of use, thus losing its sealing function. The existing structure, as Figure 3 shown, although has a certain self-compensation, but due to the limitation of the holding force (if the holding force is large, the needle will be jammed; if the holding force is small, there will be leakage), the magnitude of the elastic force of the pressing spring 22 is affected by the holding force, and the pressing spring 22 is indirectly pressed axially, so the self-compensation is not obvious, and its service life is only 4 - 8 months.

[0013] 4. Since the pressing and sealing component 2 and the bottom sealing component 21 at the front end are of a split structure, and both the pressing and sealing component 2 and the reset spring 4 at its rear end will swing during movement, it will cause the pressing and sealing component 2 and the bottom sealing component 21 to be non - coaxial, thus affecting their smoothness and sealing performance.

[0014] In summary, a new sealing device for solving the above problems has become the focus of research in this field. Summary of the Invention

[0015] The purpose of the present invention is to provide a sealing device for a spray gun coating needle, including a sealing component 6 for circumferentially sealing the coating needle 3 and a hollow bolt 7 for accommodating the sealing component 6. The sealing component 6 includes a self - compensation structure 61 at the inner end of the hollow bolt 7. The self - compensation structure 61 includes: a circumferential slot hole 611, and a self - compensation section 612 is provided on one side of the circumferential slot hole 611 close to the coating needle 3; and an elastic member 62 located in the circumferential slot hole 611 for supporting the self - compensation section 612.

[0016] Preferably, the self - compensation section 612 is a protrusion.

[0017] Preferably, the inner diameter of the protrusion is 0.05 - 0.8 mm smaller than the outer diameter of the coating needle 3.

[0018] Preferably, the length of the self - compensation section 612 is 0.1 - 8 mm.

[0019] Preferably, the circumferential slot hole 611 is a converging opening.

[0020] Preferably, the elastic member 62 is a V - shaped or U - shaped hollow metal ring with a cross - section, and the open end of the V - shape or U - shape faces the converging opening.

[0021] Preferably, the elastic member 62 is a rubber ring, and the rubber ring is assembled into the converging opening.

[0022] Preferably, the sealing component 6 further includes an interference - fit section 613, a middle section 614, and a front - end conical surface 615 arranged in sequence from the self - compensation structure 61 to the other end; the interference - fit section 613 is used for interference - fitting with the hollow bolt 7.

[0023] Preferably, the inner - hole diameter of the hollow bolt 7 corresponding to the interference - fit section 613 is 0 - 1 mm smaller than the outer diameter of the interference - fit section 613.

[0024] Preferably, the inner diameter of the middle section 614 is 0.05 - 1 mm larger than the outer diameter of the coating needle 3.

[0025] The sealing device of the spray - gun coating needle of the present utility model has the following advantages:

[0026] 1. The seal 6 of this patent is provided with a self-compensation structure 61, which can not only maintain good sealing performance for the coating needle 3, but also ensure the smooth movement of the coating needle 3 back and forth. At the same time, it can also generate continuous compensation. During normal use, the wear-resistant life is increased to more than 12 months.

[0027] 2. The seal 6 of this patent has been changed from the original split structure to the current integral structure, with better coaxiality, which is beneficial to the smoothness and sealing performance of the coating needle 3.

[0028] 3. The seal 6 of this patent is provided with a self-compensation structure 61. The seal 6 can be mass-produced through a special mold, and the original fitting tolerance accuracy is relaxed from 0.02 to 0.8, greatly reducing the difficulty of component processing and improving the efficiency of mass production. Description of the Drawings

[0029] Figure 1 . Schematic diagram of the existing spray gun structure.

[0030] Figure 2 . Schematic diagram of the assembly of the sealing components of the existing spray gun;

[0031] Figure 3 . Schematic diagram of the structure of the existing sealing structure;

[0032] Figure 4 . Schematic diagram of the structure of the sealing device assembly in Embodiment 1 of the present utility model;

[0033] Figure 5 . Schematic diagram of the structure of the sealing device after disassembly in Embodiment 1 of the present utility model;

[0034] Figure 6 . Schematic diagram of the seal structure of the sealing device in Embodiment 1 of the present utility model.

[0035] Among them, 1. Spray gun body; 11. Head coating bin; 12. Head coating needle small hole; 13. Head pressing and sealing component hole;

[0036] 2. Pressing and sealing component; 21. Bottom seal; 22. Pressing spring; 23. Matching bolt;

[0037] 3. Coating needle; 4. Return spring; 5. Trigger;

[0038] 6. Seal; 61. Self-compensation structure; 611. Circumferential groove hole; 612. Self-compensation section; 613. Interference fit section; 614. Middle section; 615. Front end cone; 62. Elastic member; 7. Hollow bolt. Detailed Implementation Modes

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with specific embodiments.

[0040] Embodiment 1:

[0041] This embodiment provides a sealing device for a spray gun paint needle, including a seal 6 for circumferentially sealing the paint needle 3 and a hollow bolt 7 for accommodating the seal 6. The seal 6 includes a self-compensation structure 61 at the inner end of the hollow bolt 7. The self-compensation structure

[0042] 61 includes: a circumferential slot 611, and a self-compensation section 612 is provided on one side of the circumferential slot 611 close to the paint needle 3; and an elastic member 62 for supporting the self-compensation section 612 in the circumferential slot 611.

[0043] The seal 6 of this embodiment is provided with a self-compensation structure 61, which can not only maintain good sealing performance for the paint needle 3, but also ensure the smoothness of the reciprocating movement of the paint needle 3; at the same time, continuous compensation can be generated, and during normal use, the wear-resistant life is increased to more than 12 months; the seal 6 is changed from the original split structure to the current integral structure, with better coaxiality, which is beneficial to the smoothness and sealing performance of the paint needle 3. The seal 6 can be mass-produced through a special mold, and the original mating tolerance accuracy is relaxed from 0.02 to 0.8, greatly reducing the difficulty of component processing and improving the efficiency of mass production.

[0044] Preferably, the self-compensation section 612 is a protrusion. In this way, the contact between the self-compensation section 612 and the paint needle 3 is a rounded contact, which is more beneficial to the reciprocating movement of the paint needle 3, and at the same time makes the sealing position more concentrated and can reduce the frictional resistance.

[0045] Preferably, the inner diameter of the protrusion is 0.05 - 0.8 mm smaller than the outer diameter of the paint needle 3. This range is both beneficial to sealing and beneficial to reducing friction, making the reciprocating movement of the needle smoother.

[0046] Preferably, the length of the self-compensation section 612 is 0.1 - 8 mm. This range is both beneficial to sealing and beneficial to reducing friction, making the reciprocating movement of the needle smoother.

[0047] Preferably, the circumferential slot 611 is closed at the mouth. This prevents the elastic member 62 from slipping out of the circumferential slot 611.

[0048] Preferably, the elastic member 62 is a V-shaped or U-shaped hollow metal ring with a cross-section, and the open end of the V-shaped or U-shaped faces the closed mouth. This structure is convenient for assembly and prevents the elastic member 62 from slipping out.

[0049] Preferably, the elastic member 62 is a rubber ring, and the rubber ring is assembled into the necking. The rubber ring is simple to manufacture and convenient to assemble.

[0050] Preferably, the seal 6 further includes an interference fit section 613, a middle section 614, and a front end conical surface 615 that are sequentially arranged from the self-compensation structure 61 to the other end; the interference fit section 613 is used for interference fitting with the hollow bolt 7.

[0051] In this way, the interference fit section 613 is used for interference fitting with the hollow bolt 7 so that the seal 6 is fixed in the hollow bolt 7; the front end conical surface 615 abuts against the bottom surface of the spray gun head pressing seal member hole 13 for sealing, preventing the paint from leaking from the head paint needle small hole 12 to the periphery of the spray gun head pressing seal member hole 13.

[0052] Preferably, the inner hole diameter of the hollow bolt 7 corresponding to the interference fit section 613 is 0 - 1 mm smaller than the outer diameter of the interference fit section 613. This range can better meet the assembly and use requirements.

[0053] Preferably, the inner diameter of the middle section 614 is 0.05 - 1 mm larger than the outer diameter of the paint needle 3. This range enables the middle section 614 of the seal 6 to contract towards the middle when the hollow bolt 7 presses and tightens the seal 6, but the size after contraction can ensure that the needle is not clamped and the gap between the needle and the inner wall of the middle section 614 is as small as possible, thereby avoiding the accumulation of the paint leaking from the head paint needle small hole 12 in this section.

[0054] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A sealing device for a paint needle of a spray gun, comprising a sealing member (6) for sealing the paint needle (3) in the circumferential direction and a hollow bolt (7) for accommodating the sealing member (6), characterized in that: The sealing member (6) comprises a self-compensating structure (61) located at the inner end of the hollow bolt (7), the self-compensating structure (61) comprising: a circumferential slot hole (611), and a self-compensating section (612) provided on a side of the circumferential slot hole (611) close to the paint needle (3); and an elastic member (62) located in the circumferential slot hole (611) for supporting the self-compensating section (612).

2. The sealing device for a paint spray gun needle according to claim 1, characterized in that: The self-compensating section (612) is a protrusion.

3. The sealing device for a paint needle of a spray gun according to claim 2, characterized in that: The inner diameter of the protrusion is 0.05-0.8 mm smaller than the outer diameter of the coating needle (3).

4. The sealing device for a paint spray gun needle according to claim 1, characterized in that: The length of the self-compensating section (612) is 0.1-8 mm.

5. The sealing device for a paint needle of a spray gun according to claim 1, characterized in that: The circumferential slot hole (611) is closed.

6. The sealing device for a paint needle of a spray gun according to claim 5, characterized in that: The elastic member (62) is a hollow metal ring with a V-shaped or U-shaped cross section, and the open end of the V-shaped or U-shaped shape faces the closing end.

7. The sealing device for a paint needle of a spray gun according to claim 5, characterized in that: The elastic member (62) is a rubber ring, and the rubber ring is assembled into the closing opening.

8. The sealing device for a paint needle of a spray gun according to claim 1, characterized in that: The sealing member (6) further comprises an interference fit section (613), a middle section (614), and a front end cone surface (615) which are arranged in sequence from the self-compensating structure (61) to the other end; the interference fit section (613) is used to perform an interference fit with the hollow bolt (7).

9. The sealing device for a paint needle of a spray gun according to claim 8, characterized in that: The inner hole diameter of the hollow bolt (7) corresponding to the interference fit section (613) is 0-1 mm smaller than the outer diameter of the interference fit section (613).

10. The sealing device for a paint needle of a spray gun according to claim 8, characterized in that: The inner diameter of the middle section (614) is 0.05-1 mm larger than the outer diameter of the coating needle (3).

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