JPH08334082A - Pump - Google Patents

Abstract

PURPOSE: To provide a silent pump which can be operated at high speed and is excellent in responsiveness and by which size reduction is facilitated and which has high efficiency and high output. CONSTITUTION: Reciprocating motion of a plunger 12 housed in a pump body 2 is made to depend on a freely extensible contractible solid element 10 connected to the plunger 12, and a frequency of the reciprocating motion of the plunger 12 is set in integer times not less than 1 of a natural frequency of check valves 22, 24 and 26, 28 arranged in a suction port 6 and an exhaust port 8 of the body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact pump applicable to a hydraulic pump such as an antilock brake for automobiles.

[0002]

2. Description of the Related Art Conventionally, an electromagnetic motor was generally used as a drive source of a pump, but recently, a more compact and highly responsive one has been required, and a piezoelectric element (Journal of the Japan Society of Mechanical Engineers) (C Edition) Volume 60 571 (1994-3) P.95
6) and magnetostrictive element (Sumitomo Light Metal Technical Report Vol.33 No.1)
P. 26) and the like have been reported.

[0003]

However, since the amount of displacement generated by the conventional element is very small, it is necessary to improve the processing accuracy of the parts used, and the output range is limited. Therefore, the development of materials having a large piezoelectric effect or magnetostrictive effect is still underway.

As a means for structurally expanding the displacement, it is possible to use the lever principle or the relationship between the cross-sectional area and the pressure, but the cost is increased and the size is increased due to the complicated structure.

Further, when a solid-state element is AC-driven, a large operating noise may be generated, or the element may generate heat and its characteristics may change. Even if the basic performance is satisfied, actual use is hindered. There was a problem.

The present invention has been made in view of the above problems of the prior art, and is capable of high-speed operation and excellent responsiveness, and is easy to downsize, highly efficient, and has a high output and a quiet pump. Is intended to provide.

[0007]

In order to achieve the above object, the invention according to claim 1 of the present application (hereinafter referred to as the first invention) has a check valve at a suction port and a discharge port of a pump chamber. Then
In the pump in which the pump chamber is expanded and contracted by the reciprocating motion of the plunger to pump the liquid, the reciprocating motion of the plunger is performed by the expandable solid element connected thereto, and the frequency of the reciprocating motion of the plunger is set to the check valve. It is characterized in that it is an integer multiple of 1 or more of the natural frequency.

In the invention according to claim 2 of the present application (hereinafter referred to as the second invention), the movable sealing component of the check valve is made of any one of a light metal material, a resin material and a ceramic material. It is a thing.

Further, the invention according to claim 3 of the present application (hereinafter referred to as the third invention) is a retractable solid-state element in which the reciprocating motion of the plunger is directly or indirectly connected to the plunger through an elastic body. The solid-state element is driven at a frequency that is an integral multiple of 1 or more of the natural frequency of the system including the solid-state element and the plunger or the solid-state element, the elastic body, and the plunger.

Further, in the invention according to claim 4 of the present application (hereinafter, referred to as a fourth invention), the reciprocating motion of the plunger is performed by a telescopic solid element connected thereto, and the solid element is applied with a sinusoidal voltage. Alternatively, it is driven by an electric current.

Further, in the invention according to claim 5 of the present application (hereinafter, referred to as a fifth invention), the reciprocating motion of the plunger is performed by a telescopic solid element connected thereto, and the force of the solid element is not transmitted. The side surface is in contact with the body via an elastic body.

[0012]

According to the first aspect of the present invention, the displacement of the solid element acts to change the volume of the pump chamber, and the frequency thereof is an integral multiple of 1 or more of the natural frequency of the check valve. Therefore, a resonance state occurs, and a large amplitude is given to the check valve to increase the opening degree of the check valve.

According to the second invention of the present application, the natural frequency of the check valve is increased by reducing the weight of the movable sealing component of the check valve.

Further, according to the third aspect of the present invention, the solid element is driven at a frequency that is an integer multiple of 1 or more of the natural frequency of the system including the solid element and the plunger, or the system including the solid element, the elastic body, and the plunger. As a result, the plunger will be displaced significantly.

Further, according to the fourth aspect of the present invention, since the solid-state element is driven by the sinusoidal voltage or current having no shocking component unnecessary for driving, the movement of the movable portion is smooth. Becomes

Further, according to the fifth invention of the present application, since the side surface of the solid-state element parallel to the expansion / contraction direction is in contact with the body through the elastic body, the expansion / contraction operation of the element is hardly affected. The heat generated inside the pump is radiated to the body via the elastic body.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a pump P1 according to a first embodiment of the present invention, in which a pump chamber 4, a suction port 6 and a discharge port 8 are formed in a body 2 of the pump P1.
The pump chamber 4 communicates with the suction port 6 and the discharge port 8.

The pump chamber 4 has a retractable solid-state element 10.
And a slidable plunger 12 whose one end surface abuts against the solid element 10 is built in, and a compression fixing spring 14 is interposed between the other end surface of the plunger 12 and the inner wall of the pump chamber 4. , The plunger 12 has a fixed spring 14
It is pressed against the solid-state element 10 by the urging force of. An annular recess 12a is formed on the outer peripheral surface of the plunger 12, and the O-ring 16 fitted in the recess 12a.
The pump chamber 4 is sealed by.

Further, check valve chambers 18 and 20 are formed in the middle of the suction port 6 and the discharge port 8, respectively, and the check valve chambers 18 and 20 each have a ball and a spring which are movable sealing parts. Check valves each of which is composed of That is, the check valve chamber 18 accommodates the suction port ball 24 biased by the compression spring 22 in the direction opposite to the liquid inflow direction, while the check valve chamber 20 stores the liquid in the check valve chamber 20 by the compression spring 26. A discharge port ball 28 biased in the direction opposite to the outflow direction is stored.

The operation of the pump P1 having the above structure will be described below. When a driving signal is sent from the driving electric circuit (not shown) to the solid-state element 10, the solid-state element 10 performs a stretching motion in response to the driving signal. Since the plunger 12 is biased to the solid element 10 by the fixed spring 14, the plunger 12 also reciprocates similarly to the solid element 10. The volume of the pump chamber 4 is forcibly expanded and contracted by the reciprocating motion of the plunger 12, and the liquid flows from the suction port 6 at the time of expansion, while the liquid is pushed out from the discharge port 8 at the time of contraction. The pump P1 can pump out the liquid by repeating this expansion and contraction. The check valve chamber 1
In the check valves housed in 8 and 20, the balls 24 and 28 are displaced according to the pressure difference between the pump chamber 4 and the outside, and the liquid passes through.

FIG. 2 shows a pump P2 according to a second embodiment of the present invention. In the structure of the first embodiment shown in FIG. 1, the solid element 10 and the plunger 12 are separated from each other so that the solid element 10 has the same structure. An elastic body 30 such as a compression spring is interposed between the and the plunger 12. The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

Here, in the configuration shown in FIG. 1 or 2, the plunger 12 has the check valves 22, 24 or 26,
28 is configured to reciprocate at a resonant frequency. More specifically, the natural frequency of the check valve, that is, the natural frequency of the ball and spring f _1r and the reciprocating frequency of the plunger f
₂ is represented by (Equation 1),

(Equation 1) f ₂ = n * f _1r n: When the plunger is reciprocated under the condition of an integer of 1 or more (Equation 1), the displacement of the solid element changes the volume of the pump chamber, Furthermore, since the frequency is an integer multiple of 1 or more of the natural frequency of the check valve, the resonance state occurs, giving a large amplitude to the check valve, increasing the opening of the check valve, and allowing the liquid to easily pass through. The pump efficiency is improved.

Further, in the configuration of FIG. 1 or FIG.
If the check valve uses steel balls, the specific gravity of iron is 7.86 g / cm ³
Considering this, the weight of a φ3 mm ball is about 0.11 g. As shown in (Equation 2), the natural frequency of the check valve is determined by the mass of the ball and the spring constant,

[Equation 2] If the spring constant of the spring used is 100 N / m, the natural frequency of this system is 150 Hz from the relationship of (Equation 2). By driving the plunger of the pump of FIG. 1 or FIG. 2 at this frequency, the check valve in the resonance state has a large amplitude,
A highly efficient pump with little loss in the valve part is realized.

The pump plunger has
300 that is an integer multiple of the natural frequency so that (Equation 2) is satisfied
The same effect can be expected by driving at Hz, 450 Hz, etc.,
It is possible to increase the pump output. Hundreds of solid elements
It is possible to use a laminated PZT-based piezoelectric element or a terphenol D (TbDyFe) -based magnetostrictive element having a distortion of ppm or more and good response.

Further, as shown in (Table 1), by using a material having a smaller specific gravity than the steel material used in the above embodiment for the ball, the natural frequency of the check valve is increased and a highly responsive check valve is obtained. realizable.

[Table 1]

That is, the weight can be reduced by constructing the ball with any one of a light metal, a resin and a ceramic material. It is possible to increase the natural frequency of the check valve by increasing the spring constant of the check valve or by reducing the ball to reduce its mass, but increasing the spring constant of the check valve opens the check valve. While the reaction force increases,
The smaller the ball, the smaller the opening area of the check valve,
The passage of liquid is blocked. By using a material having a low specific gravity for the ball, the natural frequency of the check valve can be set high without increasing the spring constant of the check valve or reducing the ball, and high pump efficiency can be obtained.

Further, in the configuration of FIG.
The solid state element 10 may be driven by the natural frequency of the system in which the plunger 12 and the plunger 12 are joined. As is clear from (Equation 2),
By increasing the weight of the plunger 12, the solid state element 10
It resonates at a natural frequency slightly lower than its own natural frequency. Therefore, the amplitude of the plunger displacement becomes larger than that when driven by the DC voltage, and the pump discharge amount in one step increases.

Further, in the structure of FIG.
The solid-state element 10 may be driven by the natural frequency of the system in which the plunger 12 is joined via the elastic body 30. Solid element 1
The system consisting of 0, the plunger 12, and the elastic body 30 has a coupled natural frequency, and when the solid-state element 10 is driven at that frequency, it resonates in the entire system. Therefore, a large plunger displacement amplitude is obtained, and the pump discharge amount increases.

In any of the examples, even if the vibration frequency of the solid-state element 10 is set to an integral multiple of 2 or more of the natural frequency of the system, a large plunger displacement is obtained by the same resonance phenomenon and the pump discharge amount is increased.

More specifically, in the configuration of FIG.
When the solid-state element 10 is driven at an integer multiple of 1 or more of the natural frequency of the system including the solid-state element 10 and the plunger 12, the solid-state element 10 is "forced to vibrate because the mass m1 is supported by the lower spring component". The plunger 12 also weighs m
The model is considered as a linear one-degree-of-freedom system as shown in FIG. In this case, by driving the solid-state element 10 at an integer multiple of 1 or more of the natural frequency of the system including the plunger 12 and the solid-state element 10, the plunger corresponding to m2 is largely displaced and the pump output is increased.

Similarly, in the configuration of FIG.
When driving the solid-state element 10 at an integer multiple of 1 or more of the natural frequency of the system consisting of 0, the plunger 12 and the elastic body 30, considering the same as in the configuration of FIG. In addition, it can be modeled in a linear two-degree-of-freedom system as shown in FIG. By driving, the plunger 12 corresponding to m2 is largely displaced and the pump output is increased.

Further, in the above embodiment, the fixing element 10
Is driven by a sinusoidal voltage or current. When driving a pump that handles liquids with a rectangular wave, etc., the shocking high frequency contained in the rectangular wave etc. causes noise, but since the sine wave does not have an unnecessary shocking component for driving, it is a moving part. The movement of is smooth and enables quiet operation.

For example, a piezoelectric element can be used as the solid-state element 10, and the piezoelectric element can be driven by a sine wave voltage of 100 Vp-p. An offset of 50 V is applied to the device so that a reverse voltage is not applied, and the device can be driven by changing the voltage from 0 V to 100 V to drive the pump quietly.

When a magnetostrictive element is used as the solid-state element 10, the same effect can be obtained by passing a current that changes with a sinusoidal waveform offset so that no reverse current is applied to a coil that generates a magnetic field. To be

FIG. 5 shows a pump P3 according to a third embodiment of the present invention. In the structure of the second embodiment shown in FIG. 2, a piezoelectric element is used as the solid element 10 and the piezoelectric element 10 expands and contracts. The space between the body 2 and the body 2 is molded with an elastic body 32 such as silicon resin or rubber so as to fill the space with the body 2 as a heat sink to enhance the thermal conductivity and to assist the heat radiation from the solid element part. It is a thing. Further, since the elastic body 32 is in contact with the side surface of the solid-state element 10 which does not transmit the force, the elastic body 32 is effectively radiated without substantially affecting the expansion / contraction operation of the solid-state element 10.

When a magnetostrictive element is used as the solid-state element 10, both the expanding and contracting magnetostrictive element and the coil for applying the magnetic field are molded with silicone resin to fill the space with the body 2 and to prevent the magnetostrictive element part and the coil from forming. Can help to dissipate heat.

As a molding material for forming an elastic body, one having a low elastic modulus (soft) and a high thermal conductivity is suitable, and a material in which metal powder, carbon powder or the like is dispersed in resin or rubber is also suitable. ing.

Of course, the elastic body 32 of FIG. 5 may be applied to the pump P1 shown in FIG.

[0039]

According to the first aspect of the present invention, the plunger and the check valve resonate with each other, and as a result, the opening degree of the valve becomes large, the liquid easily passes through, and the pump efficiency is improved.

Further, according to the second invention of the present application, by reducing the weight of the movable sealing component of the check valve, the natural frequency of the check valve can be increased and a high pump efficiency can be obtained. Become.

Further, according to the third invention of the present application, the solid element is driven at a frequency which is an integral multiple of 1 or more of the natural frequency of the system including the solid element and the plunger, or the system including the solid element, the elastic body and the plunger. As a result, the plunger is largely displaced and the pump output can be increased.

Further, according to the fourth aspect of the present invention, since the solid-state element is driven by the sinusoidal voltage or current having no shocking component unnecessary for driving, the movement of the movable portion is smooth. The operation of the pump becomes quiet.

Further, according to the fifth invention of the present application, the side surface parallel to the expanding and contracting direction of the solid element is brought into contact with the body through the elastic body, and heat is radiated to the body through the elastic body. Along with preventing abnormal heating, the high pump output can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pump according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a pump according to a second embodiment of the present invention.

FIG. 3 is a model diagram of a linear one-degree-of-freedom system corresponding to the embodiment of FIG.

FIG. 4 is a model diagram of a linear two-degree-of-freedom system corresponding to the embodiment of FIG.

FIG. 5 is a vertical sectional view of a pump according to a third embodiment of the present invention.

[Explanation of symbols]

 2 body 4 pump chamber 6 suction port 8 discharge port 10 solid state element 12 plunger 14 fixed spring 22,26 compression spring 24 suction port ball 28 discharge port ball 30 elastic body 32 elastic body

Claims (5)

[Claims] 1. A pump having check valves at an intake port and a discharge port of a pump chamber, wherein the pump chamber is expanded and contracted by reciprocating motion of a plunger to pump liquid, and the reciprocating motion of the plunger is connected and contracted. A pump, wherein the frequency of the reciprocating motion of the plunger is set to an integral multiple of 1 or more of the natural frequency of the check valve. 2. A pump having check valves at an intake port and a discharge port of a pump chamber, wherein the pump chamber is expanded and contracted by reciprocating motion of a plunger to pump up a liquid, and the reciprocating motion of the plunger is connected and contracted. A pump which is made by a freely movable solid element, wherein the movable sealing part of the check valve is made of any one of a light metal material, a resin material and a ceramic material. 3. A pump having check valves at an inlet and an outlet of a pump chamber, wherein the pump chamber is expanded and contracted by the reciprocating motion of a plunger to pump liquid, and the reciprocating motion of the plunger is directly or directly applied to the plunger. It is performed by a retractable solid element indirectly connected via an elastic body, the solid element and the plunger,
Alternatively, the pump is characterized in that it is driven at a frequency that is an integral multiple of 1 or more of the natural frequency of a system composed of a solid element, an elastic body, and a plunger. 4. A pump having check valves at an intake port and a discharge port of a pump chamber, wherein the pump chamber is expanded and contracted by reciprocating motion of a plunger to pump up a liquid, and the reciprocating motion of the plunger is connected and contracted. A pump which is made by a freely movable solid-state element and is driven by a sinusoidal voltage or current. 5. A pump having check valves at an inlet and an outlet of a pump chamber, wherein the pump chamber is expanded and contracted by a reciprocating motion of a plunger to pump up a liquid, and the reciprocating motion of the plunger is connected expansion and contraction. A pump which is formed by a freely movable solid element, and a side surface of the solid element which does not transmit a force is in contact with a body through an elastic body.