JPH0442534Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] Industrial application field The present invention relates to a pump for delivering liquids such as fuel oil and lubricating oil.

Conventional technology As a fuel pump for a conventional kerosene combustor,
Electromagnetic pumps are widely used, but since such pumps are large in size and are frequency controlled, they have the disadvantage that when a low flow rate is used, the flow rate pulsates and combustion becomes unstable. Furthermore, these electromagnetic pumps generate a lot of noise, consume a lot of power like electric pumps, and have the problem of being expensive compared to their capacity.

Therefore, it has been proposed to use a pump that uses a piezoelectric vibrator instead of the conventional electromagnetic pump. An oil feed pump is disclosed (FIG. 4). The oil pump in this example has a piezo element c on a metal disc b.
Check valves e and f are provided at both ends of a liquid pressurizing chamber d, which is constructed by opposing the vibrator a obtained by joining the vibrator a, so that the vibrator a sucks liquid by alternately deforming into concave and convex shapes. It is designed to be discharged.

However, with this type of pump, the phase of the input to the vibrator a can be controlled using a commercial power source, which has the advantage of reducing pulsation even at low flow rates, but since the amount of deformation of the vibrator a is relatively small, the required flow rate is In order to ensure this, it is necessary to take a large area, and the shape of the liquid pressurizing chamber d has to become large. As a result, air and the like tend to remain in the liquid pressurizing chamber, which absorbs changes in volume and deteriorates the pump's function, and also causes problems such as a delay in stabilizing the liquid delivery rate.

In order to solve the above-mentioned problems with conventional piezoelectric pumps, the inventors of the present invention created a pump section that sucks in and discharges liquid in a fixed direction using a reciprocating piston below the liquid surface, and supports it in a cantilevered manner. A small piezoelectric pump characterized in that a piezoelectric vibrator is provided above the liquid surface, and the motion of the vibrating end of the piezoelectric vibrator is transmitted to the piston by a joint member provided through the liquid surface. We have proposed and applied for a patent.

Problems to be Solved In this new piezoelectric pump, since the piezoelectric vibrator vibrates at a position away from the liquid, electrical insulation is easy and there is little energy loss. However, if the amplitude is increased in order to increase the output of the piezoelectric vibrator, bending or twisting will occur, and as a result, a force that is not parallel to the axis will be applied to the piston, creating a problem in that the reciprocating movement of the piston will be forced.

Therefore, an object of the present invention is to provide a long-life piezoelectric pump that operates smoothly without putting strain on the piston.

[Structure of the idea]

Means for Solving the Problems The piezoelectric pump of the present invention, which can achieve the above object, has a pump section below the liquid surface that sucks in and discharges liquid in a fixed direction using a reciprocating piston, and has a cantilever shape. A piezoelectric pump configured such that a supported piezoelectric vibrator is provided above a liquid level, and the motion of a vibrating end of the piezoelectric vibrator is transmitted to the piston by a joint member provided through the liquid level,
A through hole is provided at the rear of the piston at right angles to the axis thereof, and the cross-sectional shape of the hole is formed such that the inner diameter in the direction perpendicular to the axis is larger than the inner diameter in the direction of the axis; It is characterized in that the tip of the joint member made of a rigid rod-like body is inserted into the through hole.

An example of the piezoelectric pump of the present invention is shown in FIG. In the figure, 1 is a pump case, and a pump chamber 1a is formed at its lower end. Pump room 1a
A suction port 1c is provided on the lower side via an inlet check valve 1b, and a passage communicating with the supply port 1e is provided on the upper side via an outlet check valve 1d. Further, a cylinder part 1f is provided on the side of the pump chamber 1a, and a piston 2 is slidably mounted on the cylinder part 1f.

3 is a plate-shaped piezoelectric vibrator, the upper end 3a is fixed to form a cantilever shape, and the lower end 3b is fixed by applying an alternating voltage to electrodes provided on both sides of the piezoelectric vibrator.
is designed to vibrate (in the left-right direction in the figure). An electrically insulating joint 4 is fixed to the vibrating end 3b of the piezoelectric vibrator, and a rod-shaped joint member 5 is provided along the extending direction of the piezoelectric vibrator 3 via the joint 4.

The joint member 5 is formed of a rigid rod-shaped body, and its tip is inserted into a through hole 2a formed at the rear end of the piston 2, and the piezoelectric vibrator 3
The horizontal vibration is amplified and transmitted to the piston 2, and the piston 2 is configured to reciprocate within the cylinder portion 1f.

6 is a protective cover provided to surround the pump section including the pump chamber 1a portion, the suction port 1c, the cylinder section 1f, the piston 2, etc., and the window section 6a provided on the side surface is made of, for example, a fine woven mesh. It is blocked by a filter medium 7 made of a material such as the like, so that only liquid can pass through.

Here, HL is the upper limit liquid level and LL is the lower limit liquid level.

The piston 2 of the pump section provided below such a lower limit liquid level LL has its rear part exposed to the space within the protective cover 6 and is immersed in the liquid. The through hole 2a, through which the joint member 5 provided on the piston 2 is inserted, is formed perpendicular to the axis of the piston, as shown in FIGS.
The inner diameter Y in the perpendicular direction is larger than the inner diameter X in the axial direction. Therefore, the gap between the bar-shaped joint member 4 and the wall of the through hole 2a is small in the axial direction, with almost no play, and there is a large play in the direction perpendicular to the gap. Furthermore, the upper and lower ends of the through hole 2a are expanded in a tapered manner, so that even if the joint member 4 is inserted somewhat obliquely, the engagement with the piston 2 will not be forced.

On the other hand, 8 is a control circuit, for example, 100V AC power is supplied from a power supply line 8a, and a signal line 8b
A drive signal controlled by a flow rate adjustment signal input from the piezoelectric vibrator 3 is outputted to the piezoelectric vibrator 3 via an output line 8c.

Function In the piezoelectric pump of the present invention, the transverse vibration of the piezoelectric vibrator 3 is transmitted to the piston 2 via the rod-shaped joint member 5, and the piston 2 reciprocates to suck in and send out liquid. Since the through hole 2a of the piston 2 into which the piston 5 is inserted and engaged absorbs the bending and twisting of the piezoelectric vibrator 3 and the joint member 5, no unreasonable force other than reciprocating motion is applied to the piston 2.

[Effect of idea]

Since the piezoelectric pump of the present invention has the above-mentioned engagement structure between the piston and the joint member, it is possible to apply a large drive input to the piezoelectric vibrator and cause it to vibrate greatly in order to increase the amount of liquid delivered. Abnormal bending or twisting that occurs in the piezoelectric vibrator, joint member, etc. due to the vibration is absorbed by the engagement portion between the joint member and the piston, so the reciprocating movement of the piston is not strained. It has the advantage of significantly improving pump life.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the structure of an example of the piezoelectric pump of the present invention, Figure 2 is a sectional view of its piston, and Figure 3 is a sectional view showing the structure of an example of the piezoelectric pump of the present invention.
The figure is also a top view of the rear part of the piston, and the fourth
The figure is a sectional view of a conventional piezoelectric oil pump. 1...Pump case, 1a...Pump chamber, 1f
... Cylinder part, 2 ... Piston, 2a ... Through hole, 3 ... Piezoelectric vibrator, 4 ... Joint, 5 ... Joint member, 6 ... Protective cover, 7 ... Filter medium, 8
...control circuit.

Claims (1)

[Scope of utility model registration request] A pump section that sucks in and discharges liquid in a fixed direction using a reciprocating piston is provided below the liquid surface, and a piezoelectric vibrator supported in a cantilevered manner is provided above the liquid surface.
In a piezoelectric pump configured to transmit the motion of a vibrating end of the piezoelectric vibrator to the piston by a joint member provided through the liquid surface, the piezoelectric pump has a through hole provided at a rear part of the piston at right angles to its axis; A cross-sectional shape is formed such that the inner diameter in the direction perpendicular to the axis is larger than the inner diameter in the axial direction, and the tip of the joint member made of a rigid rod is inserted into the through hole. A piezoelectric pump characterized by being inserted through it.