JPS6344118Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a liquid injection nozzle that is attached to a robot in an automobile or other assembly line and injects adhesive or other liquid onto a workpiece.

FIG. 1 shows a conventional liquid injection nozzle, in which a main body 1 has a cylinder chamber 3 in which a piston 2 is fitted at the rear.
The front part has a conical liquid filling chamber 5 with a small-diameter injection port 4 opening at the front end, and the tip of a piston rod 6 protruding forward from the piston 2 projects into the filling chamber 5. A coil spring 7 is built into the cylinder chamber 3 between the cylinder chamber 3 and the rear end of the piston 2, and presses and biases the piston forward. The tip 6' of the piston rod 6 closes the injection port 4 from behind.

Liquid such as adhesive is pressurized and injected into the liquid filling chamber by a pump or the like from a port 5' on the side of the rear end, and in order to spray it out, two ports 3a opened at the front and rear ends of the cylinder chamber 3 are used. , 3b, fluid pressure, e.g., air, is injected into the port 3a at the front end to move the piston 2 backward in the cylinder chamber against the spring 7, and the tip of the piston rod 6 is separated from the rear end of the injection port 4 (Fig. 1). dotted line). As a result, liquid such as adhesive that is pressurized in the filling chamber is jetted out from the jet port due to the pressure. Then, switch the air that is pressurized into the cylinder chamber, and then switch to the port 3b at the rear end.
When air is forced into the cylinder chamber, the piston moves forward, and the coil spring 7 exerts a restoring force, and the tip of the piston rod 6 closes the injection port 4 from behind to stop liquid injection from the injection port 4.

In this way, ports 3 at the front and rear ends of the cylinder chamber
By switching the fluid pressure supplied to and discharged from the piston rods a and 3b, the required amount of liquid can be spouted from the filling chamber through the spout 4 using the pressure that presses the liquid into the filling chamber while the tip of the piston rod is away from the spout 4. It is possible, but this has the following problems. That is, the rear end of the injection port 4 is closed at the tip of the piston rod, but the liquid remaining in the injection port in front of it leaks out from the front end of the injection port like drool and falls as droplets. That's what I do.

For this reason, an air injection nozzle is placed near the front end of the injection port, and air is injected from the air injection nozzle in synchronization with stopping the injection of liquid to prevent the liquid leaking from the front end of the injection port from reaching the workpiece. It is dispersed like a mist. Although the amount of liquid that leaks out each time is extremely small, the amount of liquid that is wasted as mist is enormous because the liquid is sprayed numerous times every hour, and the amount of liquid that is wasted is enormous. The environment is polluted and unfavorable from a sanitary point of view. Therefore, in the present invention, the injection port is placed forward and away from the front end of the filling chamber, the piston rod is passed through the front end of the filling chamber loosely, and a flange-like valve is provided at the tip of the piston rod. This solves the problem of the conventional method by causing the liquid remaining in the injection port to be sucked in and prevented from leaking out.

Figures 2 and 3 show an embodiment of the present invention, with Figure 2 showing a cross-sectional view when the injection is stopped, and Figure 3 showing a partially sectional side view when the injection is in progress. 1st
Components that are the same as those in the conventional example shown in the drawings are designated by the same reference numerals, and description thereof will be omitted.

The inner diameter of the opening 8 at the small diameter front end of the filling chamber 5 is slightly larger than the outer diameter of the piston rod 6, and the liquid press-fitted into the filling chamber can flow out to the injection port 4 through the annular gap formed therebetween. The injection port 4 is provided at the center of a cap nut-shaped nozzle tip 10 screwed onto the outer periphery of a projecting tube 9 concentrically projecting from the front end of the filling chamber, and is spaced forward from the front end of the filling chamber. A valve 11 is provided at the tip of the piston rod 6, which loosely passes through the front end of the filling chamber, and extends like a brim. The rear surface of the filling chamber contacts the front end of the filling chamber and seals the front surface of the opening 8 (FIG. 2). Also, when air is forced into the port 3b at the rear end of the cylinder chamber to move the piston forward, the valve 11 moves away from the front end of the filling chamber without blocking the rear end of the injection port 4, and the liquid in the filling chamber flows through the opening 8 and the nozzle tip. It can be ejected from the injection port 4 through the inside of the 10.

Therefore, in order to stop the injection of liquid from the injection port 4, the piston rod 6 can be moved back with the piston 2, and the opening 8 can be closed with the valve 11 at the tip of the piston rod. At this time, the valve 11 retracts the interior 10' of the nozzle chip 10 to create a negative pressure inside the nozzle chip, and due to this negative pressure, the liquid remaining inside the injection port is sucked into the inside of the nozzle chip, and the liquid remaining inside the nozzle chip is sucked into the inside of the nozzle chip. It is retained together with the liquid inside the nozzle tip and does not leak out. In this embodiment, the inner diameter of the protruding cylinder 9 on which the nozzle tip is attached on the outer periphery is slightly larger than the outer diameter of the valve 11, and the front end of the inner periphery has an oblique chamfered part 9' whose diameter is enlarged forward. The valve 11 also has a corresponding oblique chamfer 11' on its rear face. This double-sided chamfered portion 9', 1
1' is a piston rod 6 for ejecting liquid.
When the valve 11 is moved forward, the liquid flows through the valve 11 as shown in FIG.
A tapered passage is formed to allow the fluid to diffuse around the inside of the nozzle tip and smoothly flow out from the inside of the protruding cylinder into the inside of the nozzle tip. At the center of the front surface of the valve 11, a tapered protrusion 12 is provided which protrudes shallowly into the injection port 4, and at the rear end of the injection port 4, the inner diameter is expanded rearward to correspond to the projection 12. When the tapered portion 4' is formed, the liquid is guided from the inside of the nozzle tip by the projection 12 and the tapered portion 4', flows smoothly into the injection port, and is ejected from the injection port.

In this case, the back of the protruding cylinder 9, that is, the filling chamber 5
A chamfered valve seat 5a is provided on the front end surface of the valve 11 so that the chamfered portion 11' of the rear surface of the valve 11 comes into contact with the chamfered valve seat 5a. Of course, the rear surface of the valve may be a flat surface without the chamfered portion 11'.

In this way, according to the present invention, it is possible to provide a liquid injection nozzle that does not leak any liquid every time the liquid injection is stopped, and wasteful consumption of liquid is prevented, and if the liquid is, for example, an expensive adhesive, a huge amount of waste can be saved. This not only saves time but also contributes to preventing environmental pollution around the assembly line.

[Brief description of the drawings]

Fig. 1 is a longitudinal sectional view of a conventional liquid injection nozzle, Fig. 2 is a longitudinal sectional view of an embodiment of the liquid injection nozzle of the present invention when injection is stopped, and Fig. 3 shows a part of the same liquid injection nozzle when injection is stopped. This is a cross-sectional side view, in which 1 is the main body, 2 is a piston, 3 is a cylinder chamber, 4 is an injection port, 5 is a filling chamber, 6 is a piston rod, 8 is an opening at the front end of the injection chamber, and 10 is a nozzle tip. , 11 indicates a valve.

Claims (1)

[Scope of utility model registration request] The rear part of the main body 1 is provided with a cylinder chamber 3 in which the piston 2 is fitted, and the front part of the main body is provided with an opening 8 at the front end.
A nozzle tip 10 is provided with a filling chamber 5 into which a pressurized liquid is injected, and a nozzle tip 10 having an injection port 4 communicating with the opening 8 at the front end of the filling chamber.
is provided protrudingly to connect the injection port 4 to the opening 8 at the front end of the filling chamber.
The piston 2 is provided with a piston rod 6 that passes through the filling chamber 5, loosely penetrates an opening 8 at its front end, and projects its tip into the inside of the nozzle tip 10. In order to stop the liquid ejected from the injection port 4 by retracting the piston 2 in the cylinder chamber 3, the tip of the piston rod 6 is in contact with the front end of the filling chamber 5, and an opening 8 at the front end of the filling chamber is provided. A liquid injection nozzle characterized in that a closing valve 11 is provided in a flange-like manner.