JPH0442535Y2 - - 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 are 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 pump is disclosed (FIG. 5). 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 supply, 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 level, and the motion of the vibrating end of the piezoelectric vibrator is transmitted to the piston by a joint member provided through the liquid level. We have proposed and applied for a patent.

Problems to be Solved In this new piezoelectric pump, one end of the piezoelectric vibrator is fixed in the form of a cantilever, but it is difficult to position the piezoelectric vibrator when fixing it, and the fixed part may become damaged due to repeated stress being applied to the fixed part. Since it is easy to loosen, the length from the fixed end to the vibrating end varies, which causes the problem that the amount of liquid fed becomes uneven and tends to become unstable.

Therefore, the object of the present invention is to provide a piezoelectric pump that is highly accurate in the amount of liquid sent, is stable, and has a long life.

[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,
The piezoelectric vibrator is clamped and fixed by fixing members from both sides of the fixed end portion where no electrode is provided,
The present invention is characterized in that the edge position of the fixing member and the edge position of the electrode match, and the electrode terminal portion is covered with the fixing member.

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 piezoelectric vibrator 3 used in the present invention has a structure as shown, for example, in FIG. vibrating end 3 having mounting holes 31d and 31e for coupling with
A plate-shaped piezoelectric ceramic body 32 is bonded to both sides of a base body 31 on which 1c is formed, and a metal electrode 33 is further laminated on the surface thereof. The fixing member 9 is made of hard plastic, for example, and has a frame 9a on its periphery and a conductor accommodating groove 9b in the center, and has a first clamping part 9c that clamps the fixed end 31a of the base. is provided with a coupling hole 9e and a pin 9f for fusion bonding, and is also provided with a second clamping portion 9d for clamping the fixed end portion 32a of the piezoelectric ceramic body 32. Such a fixing member 9 is attached from both sides of the fixed end 3a of the piezoelectric vibrator, which consists of a fixed end 31a of the base and a fixed end 32a of the piezoelectric ceramic body, and each pin 9f is attached through the mounting hole 31b. It is fitted into the mating coupling hole 9e, and the tip of the pin 9f is melted and deformed using a method such as ultrasonic welding, and then solidified to be bound together. On this occasion,
Since the tip of the terminal portion 33b extending from the upper edge 33a of the electrode 33 is located inside the conductor housing groove 9b, the thickness of the conductor (not shown) and the thickness of soldering depend on the piezoelectric vibrator. This has no effect on fixing the fixed end 3a. The upper edge 33a of the electrode is formed to match the lower edge 9g of the fixing member 9, so that the surface of the electrode 33 is not held between the fixing member 9.

Further, the vibrating end 3b of the piezoelectric vibrator 3 is connected to the base body 31
The piezoelectric ceramic body 32 is bonded to the vibrating end portion 31c extending downward and the base body 31.
The joint 4 and the vibration end 3b are connected in substantially the same way as the fixing member 9 and the fixed end 3a, and the surface of the electrode 33 is not clamped by the joint 4.

Note that the fixing member 9 is fitted and fixed in a piezoelectric vibrator accommodating portion formed in the upper part of the pump case 1.

The joint member 5 is inserted into a through hole 2a formed at the rear end of the piston 2 near its tip, and amplifies the horizontal vibration of the piezoelectric vibrator 3 and transmits it to the piston 2, so that the piston 2 It is configured to move back and forth within the

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.

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 The piezoelectric pump of the present invention is configured to transmit the vibration of the piezoelectric vibrator 3 to the piston 2 via the joint member, but the electrode 33 of the piezoelectric vibrator 3 is held between the fixing members 9. Also, since it is not clamped by the joint 4, mechanical deformation due to electrostriction of the piezoelectric vibrator 3 is not hindered, and the clamping force of the fixing member 9 does not decrease due to deformation stress from the piezoelectric vibrator 3. .

[Effect of idea]

The piezoelectric pump of the present invention has the mounting structure for the piezoelectric vibrator as described above, so it can perform highly efficient liquid pumping operation without losing the vibration energy of the piezoelectric vibrator at the fixed end or the vibrating end. , there is little risk of loosening of the connections at the fixed end or the vibrating end. Furthermore, it is extremely easy to align the edge of the electrode with the edge of the fixing member or joint, which improves assembly accuracy and reduces variation in the mechanical output characteristics of the piezoelectric vibrator, resulting in high reliability. Summer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of an example of the piezoelectric pump of the present invention, FIG. 2 is a front view of the piezoelectric vibrator, and FIG. 3 is a diagram showing the fixing member connected to the fixed end of the piezoelectric vibrator. Front view a and cross-sectional view b, and Figure 4 is a front view a of the joint connected to the vibrating end of the piezoelectric vibrator.
and a side view b, and FIG. 5 is a sectional view of a conventional piezoelectric oil pump. 1...Pump case, 1a...Pump chamber, 1f
... Cylinder part, 2 ... Piston, 3 ... Piezoelectric vibrator, 3a ... Fixed end, 3b ... Vibration end, 4 ...
Joint, 5... Joint member, 6... Protective cover, 7... Filter medium, 8... Control circuit, 9... Fixing member.

Claims (1)

[Scope of utility model registration request] A pump section that draws 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 the vibrating end of the piezoelectric vibrator to the piston by a joint member provided through the liquid surface, the piezoelectric vibrator has a fixed end portion where an electrode is not provided. A piezoelectric pump, characterized in that it is clamped and fixed by fixing members from both sides, the edge position of the fixing member matches the edge position of the electrode, and the electrode terminal portion is covered with the fixing member. .