JPH0239592Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a constant flow discharge device for continuously discharging high viscosity fluid such as unvulcanized rubber liquid or grease from a discharge nozzle at a constant flow rate.

In the case of low-viscosity fluids such as hot-melt thermoplastic adhesives, which have a relatively low viscosity compared to the high-viscosity fluids mentioned above, it is possible to continuously discharge them at a constant flow rate using a gear pump. Due to its viscous resistance, it is impossible to pump high-viscosity fluids with gear pumps, so reciprocating pumps, generally called plunger pumps or piston pumps, are driven by pneumatic or hydraulic pressure. This is possible only by

A conventional fluid discharge device using this type of reciprocating pump has a structure shown in FIG. That is, the high viscosity fluid m filled in the tank 1 is fed through a pressure channel 3 by a well-known reciprocating air pump (plunger pump) P operated by compressed air from a compressed air supply source 2. The high viscosity fluid is discharged from the discharge nozzle 4 to coat the workpiece to a predetermined thickness. By the way, the pulsating pressure of the reciprocating air pump P is loaded on the high viscosity fluid m sent through the pressure feeding channel 3, and the fluid m pumped by the air pump P has a feeding volume as shown in _A1 . As a result, the discharge volume of the high-viscosity fluid m continuously discharged from the discharge nozzle 4 increases and decreases over time as shown in _A2 , and the coating thickness on the workpiece surface increases. It was difficult to maintain a constant thickness. In order to eliminate this variation in coating thickness, workers use their skill to adjust the coating speed according to the increase in the discharge amount over time, but these coating operations can be automated or robotized. In order to achieve this, the above-mentioned feed volume must be kept constant at all times. In FIG. 1, 5 is a piston of a reciprocating air pump P, 6 is an accumulator provided in the middle of the pressure passage 3, and 7 is a switching valve.

This invention solves the above-mentioned difficulties and allows a constant volume of high-viscosity fluid to be discharged from a discharge nozzle over time, thereby eliminating variations in coating thickness.

FIG. 2 shows an embodiment of this invention, in which a worm 8 on the drive shaft 14 side, which is directly or indirectly connected to a drive source M such as an electric motor, is placed in the middle of the pressure flow path 3.
A gear pump 10 such as a gear pump or a trochoid pump is interposed, which is transmitted via a self-locking mechanism 15 from a worm wheel 9 on the driven shaft 13 side that meshes with the worm wheel 9. In addition, in the figure, 11 is a gearbox, and 12 is a pump casing, which are each schematically shown. Furthermore, the same components as those in the structure shown in FIG. 1 are denoted by the same reference numerals, and the explanation thereof will be omitted. To explain this operating principle, the reciprocating air pump P has a 180 to 300
With the pump pulsating pressure of Kg/ ^cm2 , the high viscosity fluid m is
As shown in A ₁ , it is sent to the gear pump 10 with the amount of feed volume increasing and decreasing over time. At this time, the gear pump 10 acts as a gear motor due to the pump pulsating pressure P ₁ as shown in FIG. load. However, since the worm wheel 9 of the self-locking mechanism 15 attached to the driven shaft 13 is engaged with the worm 8 on the drive shaft 14 side, the driven shaft 13 is self-locked by the worm 8.

On the other hand, the drive shaft 14 of the worm 8 is connected directly or indirectly to a drive source M via a transmission or the like, and the worm 8 forms a self-locking mechanism 15.
The worm wheel 9 is allowed to rotate only by the rotation angle of the drive source M. Therefore, the gear pump 10 is allowed to rotate according to the rotation speed set by the drive source M, and the gear pump 10 is prevented from being rotated by the pulsating pressure of the reciprocating air pump P. The high viscosity fluid is pumped at a constant pressure without being affected by the pulsating pumping pressure according to the constant rotational speed of the driving source M, that is, the rotational speed of the gear pump 10.
A constant volume is fed by _P2 , and a constant high viscosity fluid m is continuously discharged from the discharge nozzle 4 as shown in B.

Therefore, according to this invention, by interposing a gear pump that is constantly rotated at a constant rate by a driving source in the middle of a high-viscosity fluid pressure flow path, the pump is not affected by the pulsating pumping pressure peculiar to a reciprocating pump. High viscosity fluid can be discharged from the discharge nozzle without any problems.
As a result, there is no variation in the coating thickness on the surface to be processed, making it possible to automate or robotize this coating work.

However, simply interposing a gear pump in the above-mentioned pumping path will not work if the pulsating pumping pressure by the reciprocating pump exceeds the pumping rotation speed of the gear pump.
The pumping pressure causes the gear pump to act as a gear motor, and the gear pump also rotates pulsatingly in synchronization with the pulsating pressure of the reciprocating pump, which makes it impossible to uniformly pump the high viscosity fluid. Become.

However, according to the present invention, the gear pump in the pressure feeding path is connected to the drive source via a self-locking mechanism consisting of a worm on the drive shaft side and a worm wheel on the driven shaft side that meshes with the worm, so the pulsation of the reciprocating pump is reduced. When the pumping pressure exceeds the pumping rotation speed of the gear pump, the self-locking function unique to the worm gear of the self-locking mechanism is activated, which allows the pump to adjust to the always constant pumping pressure of the gear pump without being affected by the pulsating pumping pressure. High viscosity fluid can be sent out, and pressure feeding control is easier.

Furthermore, as an incidental effect, as mentioned above, the gear pump is loaded with a force that attempts to rotate it as a gear motor due to the pulsating pumping pressure, and therefore this pulsating gear pump is used as a driving source. Therefore, it is only necessary to control the rotation speed to a constant number, and as a result, it is possible to reduce the output of the drive source.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional high viscosity fluid pumping and discharging device of this type. FIG. 2 is an explanatory diagram showing one embodiment of this invention, and FIG. 3 is an explanatory diagram of the main part thereof. m... High viscosity fluid, P... Reciprocating pump, M...
... Drive source, 3 ... Pressure flow path, 4 ... Discharge nozzle,
8...Worm, 9...Worm wheel, 10
... Gear pump, 13 ... Driven shaft, 14 ... Drive shaft, 15 ... Self-lock mechanism.

Claims (1)

[Scope of utility model registration request] In a fluid discharge device in which a high viscosity fluid is discharged from a discharge nozzle through a pressure channel using a reciprocating pump, a gear pump is interposed in the middle of the pressure channel, and the gear pump is connected to a worm on the drive shaft side. A constant flow discharge device connected to a drive source via a self-locking mechanism consisting of a worm wheel on the driven shaft side that engages with the worm wheel.