Piezoelectric valve

Abstract

To provide a piezoelectric type valve that reduces ripples generated in a displacement waveform of a valve element and can discharge a compressed gas from a gas discharge port in a stable state.SOLUTION: A piezoelectric type valve includes: an actuator for driving a valve element; a valve seat plate for fixing the actuator; and a body case for storing the valve seat plate therein. The actuator includes: a proximal part fixed to the valve seat plate; a piezoelectric element whose one end is connected to a fitting surface of the proximal part and which extends in a first longitudinal direction; a support part integrally provided in the proximal part and extending in a second longitudinal direction intersecting the first longitudinal direction in parallel with the piezoelectric element; an action part connected to the other end of the piezoelectric element and a tip part of the support part and displacing in a displacement direction different from the first longitudinal direction and the second longitudinal direction with expansion and contraction of the piezoelectric element; and the valve element provided on a side of the direction in which the action part displaces. The support part includes: a constricted part in an intermediate part extending in the second longitudinal direction and fixed to the valve seat plate on a side of the proximal part as compared to the constricted part.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a piezoelectric valve that opens and closes a valve by utilizing the displacement of a piezoelectric element.

Background Art

[0002] Conventionally, a piezoelectric valve that opens and closes a valve by utilizing the displacement of a piezoelectric element and ejects a compressed gas is well known (see Patent Documents 1 and 2).

[0003] The piezoelectric valves described in Patent Documents 1 and 2 include an actuator that utilizes the characteristics of a piezoelectric element having excellent high-speed response performance, and the actuator is provided with a displacement amplification mechanism that amplifies a small displacement of the piezoelectric element based on the principle of a lever.

[0004] Since the piezoelectric valve has excellent responsiveness, when it is used as an ejector valve of an optical sorter for particulate matter such as rice grains to remove defective products, good products are less likely to be wound around and removed, and it has been found from tests and empirical rules that the mixing rate of defective products on the side of the removed defective products is higher than that of electromagnetic valves.

[0005] By the way, when the piezoelectric valve is used as an ejector valve of the optical sorter or the like, for example, as described in Patent Document 2, it is directly and continuously mounted on a manifold having a space inside which compressed air is supplied from a compressed air source, and a large number of nozzle holes are opened at the tip of the ejector.

[0006] However, the piezoelectric valves described in Patent Documents 1 and 2 house a valve seat plate on which the actuator is fixed in a case of the valve body. The actuator is provided with a displacement amplification mechanism having a complex structure including an arm and a leaf spring, etc., and since the thickness and width dimensions of the actuator cannot be reduced, there has been a problem that it is difficult to reduce the pitch of the air discharge ports when providing a plurality of air discharge ports.

[0007] Therefore, the present inventors have proposed a piezoelectric valve in which the actuator is provided with a displacement amplification mechanism having a simple structure (see Patent Document 3. Hereinafter, referred to as the "prior invention").

[0008] According to the piezoelectric valve of the prior invention, since the dimensional thickness and width of the actuator can be made smaller than before, when a plurality of actuators are provided, the pitch of the air discharge ports can be made smaller than that of the conventional piezoelectric valve.

[0009] However, in the piezoelectric valve of the prior invention, when a driving voltage is applied to the piezoelectric element in the actuator and the piezoelectric element is extended to drive the valve body to open the valve, and the displacement amount of the valve body is measured, it is confirmed that ripples occur in the displacement waveform, and there is concern that compressed air cannot be discharged from the air discharge port in a stable state. Therefore, there is room for further improvement.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention improves the piezoelectric valve of the prior invention, and aims to provide a piezoelectric valve that reduces the ripples generated in the displacement waveform of the valve body in the actuator and can discharge compressed gas from the gas discharge port in a stable state.

Means for Solving the Problems

[0012] To achieve the above object, the present invention An actuator for driving a valve body, A valve seat that contacts and separates from the valve body and a discharge passage, and a valve seat plate for fixing the actuator, A piezoelectric valve comprising a main body case for housing the valve seat plate, The actuator includes, A base fixed to the valve seat plate, A piezoelectric element having one end connected to the mounting surface of the base and extending in a first longitudinal direction, A support portion provided integrally with the base and extending in a second longitudinal direction intersecting the first longitudinal direction alongside the piezoelectric element, An acting portion connected to the other end of the piezoelectric element and the tip of the support portion, and displacing in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element expands and contracts, The valve body provided on the side of the acting portion in the displacement direction and driven by the displacement of the acting portion, The support portion has a constricted portion in an intermediate portion extending in the second longitudinal direction, and the constricted portion and The base using the mounting hole provided between Is fixed to the valve seat plate, The main body case, A gas supply port to which compressed gas is supplied, A gas discharge port for discharging the compressed gas supplied from the gas supply port through the discharge passage of the valve seat plate by the separation between the valve body and the valve seat, It is characterized by comprising.

[0013] Also, in order to achieve the above object, the present invention provides, A plurality of actuators for individually driving a plurality of valve bodies in parallel planes, A valve seat plate having a plurality of valve seats and discharge passages that individually contact and separate from the plurality of valve bodies, and fixing the plurality of actuators, A piezoelectric valve comprising a main body case for housing the valve seat plate, Each of the plurality of actuators, A base fixed to the valve seat plate, A piezoelectric element having one end connected to the mounting surface of the base portion and extending in a first longitudinal direction, A support portion provided integrally with the base portion and extending in a second longitudinal direction intersecting the first longitudinal direction alongside the piezoelectric element, An acting portion connected to the other end of the piezoelectric element and the tip of the support portion, and displacing in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element expands and contracts, A valve body provided on the side in the displacement direction of the acting portion and driven by the displacement of the acting portion, and comprising: The support portion has a constricted portion in an intermediate portion extending in the second longitudinal direction, and the constricted portion and The base portion using the mounting hole provided between Is fixed to the valve seat plate, The main body case, A gas supply port to which compressed gas is supplied, A plurality of gas discharge ports for individually discharging the compressed gas supplied from the gas supply port through the respective discharge paths of the valve seat plate by the separation of the plurality of valve bodies and the plurality of valve seats, Characterized by comprising.

[0014] The present invention, It is preferable that the support portion is provided integrally with the base portion by being integrally formed with the base portion from a metal material such as a stainless steel material containing an Invar material, for example.

[0015] Also, the present invention, The support portion can also be provided integrally with the base portion by attaching a separate member made of, for example, a stainless steel material containing an Invar material to the base portion.

[0016] The present invention, It is preferable that the base portion is fixed to the valve seat plate at least on the side to which one end of the piezoelectric element is connected. The present invention, The base portion can also be fixed to the valve seat plate on the side where the support portion is provided.

[0017] The present invention Preferably, the displacement amount of the valve body is adjusted by the length from the constricted portion to the tip portion of the support portion.

[0018] The present invention A plurality of mounting holes are provided in the support portion on the side of the base portion rather than the constricted portion and along the second longitudinal direction between the constricted portion and the base portion. Preferably, the support portion is screwed to the valve seat plate using at least one of the mounting holes.

[0019] The present invention Preferably, at least one of the one end portion or the other end portion of the piezoelectric element is connected to the mounting surface of the base portion or the acting portion via a connecting portion made of a material having a larger linear expansion coefficient than that of the support portion.

[0020] The present invention The connecting portion is provided integrally with the acting portion. Preferably, the other end portion of the piezoelectric element is connected to the acting portion via the connecting portion made of a material having a larger linear expansion coefficient than that of the support portion.

[0021] The present invention Preferably, the connecting portion is provided integrally with the acting portion by being integrally formed with the acting portion from a metal material such as an aluminum material.

[0022] Also, the present invention The connecting portion can also be provided integrally with the acting portion by attaching a separate member made of, for example, an aluminum block or the like to the acting portion.

[0023] The present invention Preferably, the actuator further includes a compression member that is connected to each of the base portion and the acting portion and compresses the piezoelectric element in the first longitudinal direction.

[0024] The present invention It is preferable that the actuator includes a compression member that is connected to each of the base portion and the acting portion and compresses the piezoelectric element in the first longitudinal direction, and is located on a substantially central axis of the piezoelectric element.

[0025] The present invention It is preferable to fill a gap formed between the base portion and the acting portion and between the piezoelectric element and the support portion with silicone, and fill the gap with the silicone.

[0026] The present invention It is preferable to make the gaps formed between the base portion and the acting portion and between the piezoelectric element and the support portion at equal intervals, and fill the gaps with the silicone.

[0027] The present invention It is preferable to fill a gap formed between the base portion and the acting portion and between a side where the piezoelectric element extends in the first longitudinal direction and a side where the support portion extends in the second longitudinal direction with silicone, and fill the gap with the silicone.

[0028] The present invention It is preferable to make the gaps formed between the base portion and the acting portion and between a side where the piezoelectric element extends in the first longitudinal direction and a side where the support portion extends in the second longitudinal direction at equal intervals.

Effects of the Invention

[0029] The piezoelectric valve of the present invention is such that the actuator includes a base portion fixed to the valve seat plate, a piezoelectric element having one end connected to the mounting surface of the base portion and extending in a first longitudinal direction, a support portion provided integrally with the base portion and extending in a second longitudinal direction intersecting the first longitudinal direction beside the piezoelectric element, an action portion connected to the other end of the piezoelectric element and the tip of the support portion and displaced in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element expands and contracts, and a valve body provided on the side of the action portion in the displacement direction of the action portion and driven by the displacement of the action portion. The support portion has a constricted portion in an intermediate portion extending in the second longitudinal direction, and is fixed to the valve seat plate on the side of the base portion rather than the constricted portion. Therefore, compared with a conventional piezoelectric valve, ripples generated in the displacement waveform of the valve body in the actuator are reduced, and compressed gas can be discharged from the gas discharge port in a stable state.

[0030] If the piezoelectric valve of the present invention is such that the actuator adjusts the displacement amount of the valve body according to the length from the constricted portion to the tip of the support portion, the discharge amount of the compressed gas discharged from the gas discharge port can be adjusted.

[0031] If at least one of the one end or the other end of the piezoelectric element of the piezoelectric valve of the present invention is connected to the mounting surface of the base portion or the action portion via a connecting portion made of a material having a larger linear expansion coefficient than that of the support portion, the influence of thermal expansion or thermal contraction of the piezoelectric element due to temperature change can be reduced or eliminated.

[0032] If the piezoelectric valve of the present invention is such that the actuator further includes a compression member connected to each of the base portion and the action portion and compressing the piezoelectric element in the first longitudinal direction, damage to the piezoelectric element, which is easily damaged by a tensile load, can be prevented.

[0033] In the piezoelectric valve of the present invention, if the actuator is connected to each of the base portion and the working portion, and the compression member that compresses the piezoelectric element in the first longitudinal direction is positioned on the substantially central axis of the piezoelectric element, a torsional force by the compression member does not act on the piezoelectric element, and damage to the piezoelectric element can be effectively prevented.

[0034] In the piezoelectric valve of the present invention, if a gap formed between the base portion and the working portion and between the piezoelectric element and the support portion is filled with silicone, ripples generated in the displacement waveform of the valve body can be more effectively reduced.

[0035] In the piezoelectric valve of the present invention, if a gap formed between the base portion and the working portion and between the piezoelectric element and the support portion is made equidistant and the gap is filled with the silicone, filling of the silicone into the gap can be easily performed.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0037] Embodiments of the present invention will be described with reference to the drawings. [Basic Configuration of Piezoelectric Valve] First, the basic configuration of the piezoelectric valve in the present invention will be described. FIG. 1 shows a perspective view of the piezoelectric valve. FIG. 2 shows an explanatory view of the piezoelectric valve as viewed from the side. The piezoelectric valve 1 includes a valve body 2, an actuator 3 described later, and a valve seat plate 4 described later disposed inside the valve body 2 with the actuator 3 fixed thereto.

[0038] The valve body 2 is a case with an open rear surface (lower surface in FIGS. 1 and 2), and inside it includes a gas pressure chamber that receives supply of compressed gas from an external compressed gas supply source (not shown). In addition, on the front surface (upper surface in FIGS. 1 and 2) of the valve body 2, a connector portion 5 for mounting to a manifold (not shown) having a space inside which compressed gas is supplied from a compressed gas source is provided.

[0039] On the front surface of the connector portion 5, a gas suction port 51 for sucking compressed gas into the valve body 2 and a plurality of gas discharge ports 52 for discharging the compressed gas are open. In addition, on the front surface of the valve body 2, a gas supply port (not shown) communicating with the gas suction port 51 of the connector portion 5 and a plurality of gas discharge ports (not shown) communicating with each gas discharge port 52 are open. The rear surface of the valve body 2 is closed by a cover body 6, and a wiring connector 61 for supplying power to a piezoelectric element 32 described later is disposed on the cover body 6.

[0040] FIG. 3 shows a perspective view of a state where an actuator is fixed to a valve seat plate. Here, a state where the actuator of the prior invention is fixed is shown as an example of the actuator. FIG. 4 is an explanatory view of a state where an actuator is fixed to a valve seat plate, and shows a view seen from the side surface side of the valve seat plate in FIG. 3. FIG. 5 is an explanatory view of a state where an actuator is fixed to a valve seat plate, and shows a view seen from the front surface side of the valve seat plate in FIGS. 3 and 4. The piezoelectric valve 1 houses a valve seat plate 4 to which an actuator 3 is fixed inside the valve body 2. The valve seat plate 4 is an example of a valve seat plate to which two actuators can be attached, has a valve seat portion 41 at the central portion, and valve seats 42 against which valve bodies 35 of the actuator 3 abut are provided on both opposite side surfaces of the valve seat portion 41, respectively.

[0041] On one surface side of the valve seat plate 4, a mounting portion 43 of the actuator 3 is formed at a position facing one side surface of the valve seat portion 41. On the other surface side of the valve seat plate 4, a mounting portion 44 of the actuator 3 is formed at a position facing the other side surface of the valve seat portion 41. The two actuators 3 are disposed at the respective mounting portions 43 and 44 of the valve seat plate 4 and fixed by screws so that the respective valve bodies 35 face the respective valve seats 42.

[0042] A plurality of discharge passages 45 that open to the valve seat surfaces of the respective valve seats 42 are formed in the valve seat portion 41, and the respective discharge passages 45 open to the front surface (upper surface in FIG. 4) of the valve seat plate 4. The valve seat plate 4 is disposed inside the valve body 2 with the two actuators 3 fixed thereto, and the front surface is fixed by screws from the front surface side of the valve body 2, so that each discharge passage 45 communicates with each gas discharge port that opens to the front surface of the valve body 2.

[0043] The piezoelectric valve 1 is configured such that two valve seat plates 4 are accommodated side by side in the width direction within the case of the valve body 2, and four gas discharge ports are opened on the front surface of the valve body 2.

[0044] Note that, although the piezoelectric valve is configured such that four actuators are disposed within the case of the valve body 2 and four gas discharge ports are opened on the front surface of the valve body, the present invention is not limited thereto, and one or more actuators can be disposed within the valve body.

[0045] [Actuator of the prior invention] FIG. 6 shows an explanatory diagram of the actuator included in the piezoelectric valve of the prior invention. The actuator 3 of the prior invention includes a base portion 31 fixed to the valve seat plate, a piezoelectric element 32 having one end connected to the mounting surface of the base portion 31 and extending in a first longitudinal direction, and a support portion 33 integrally formed with the base portion 31 and extending in a second longitudinal direction intersecting the first longitudinal direction and alongside the piezoelectric element 32.

[0046] Further, the actuator 3 of the prior invention includes an acting portion 34 connected to the other end of the piezoelectric element 32 and the tip end portion of the support portion 33, and displacing in a direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element 32 expands and contracts, and a valve body 35 provided on one side surface in the displacement direction on the tip end side of the acting portion 34 and driven by the displacement of the acting portion 34.

[0047] As the piezoelectric element 32 expands and contracts, the acting portion 34 of the actuator 3 displaces in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction within a plane substantially parallel to the plane including the first longitudinal direction and the second longitudinal direction. At that time, by providing the constriction portion 331 in the middle portion of the support portion 33 extending in the second longitudinal direction, the displacement of the acting portion 34 accompanying the expansion and contraction of the piezoelectric element 32 can be enlarged.

[0048] A connecting member 311 made of, for example, an aluminum block or the like can be attached to the mounting surface of the base portion 31.

[0049] Further, the actuator 3 can be connected between the base portion 31 and the acting portion 34 by a compression member 36.

[0050] FIG. 7 shows an explanatory diagram of the displacement waveform of the valve body in the actuator of the prior invention. The displacement waveform of the valve body 35 shown in FIG. 7 is obtained by measuring the displacement amount of the valve body 35 when a drive voltage is applied to the piezoelectric element 32 in the actuator 3 of the prior invention shown in FIG. 6 and the piezoelectric element 32 is extended to drive the valve body 35 to open by a laser measuring instrument.

[0051] The experiment was conducted by applying a drive voltage to the piezoelectric element 32 based on the method described in [Examples] of Japanese Patent Application Laid-Open No. 2017-160973. The experimental conditions are as follows. Note that each time condition of the input signal was set to an optimum value at which there are few ripples generated in the displacement waveform of the valve body. (1) Drive voltage: 72 V (2) Input signal: First prepulse time t1 = 0.097 ms First pause time t2 = 0.077 ms Second prepulse time t3 = 0.6 ms Second pause time t4 = 0.01 ms Main pulse time t5 = 0.216 ms (Power-on time of piezoelectric element: 1 ms)

[0052] As shown in FIG. 7, it can be confirmed that in the actuator 3 of the prior invention, a plurality of large ripples considered to be due to resonance are generated in the displacement waveform of the valve body. Therefore, there is a concern that the compressed gas is not discharged stably from the gas discharge port in the piezoelectric valve of the prior invention.

[0053] [Actuator of the present invention] The piezoelectric valve of the present invention improves the actuator in the piezoelectric valve of the prior invention.

[0054] [Example 1] FIG. 8 shows an explanatory diagram of the actuator in Embodiment 1 of the present invention. The actuator 3 of Embodiment 1 includes a base 31 fixed to a valve seat plate 4, a piezoelectric element 32 having one end connected to the mounting surface of the base 31 and extending in a first longitudinal direction, and a support portion 33 provided integrally with the base 31 and extending in a second longitudinal direction intersecting the first longitudinal direction alongside the piezoelectric element 32.

[0055] Further, the actuator 3 of Embodiment 1 is connected to the other end of the piezoelectric element 32 and the tip of the support portion 33, and includes an acting portion 34 that is displaced in a direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element 32 expands and contracts, and a valve body 35 provided on one side surface in the displacement direction on the tip side of the acting portion 34 and driven by the displacement of the acting portion 34.

[0056] In the actuator 3 of Embodiment 1, the base 31 includes the side to which one end of the piezoelectric element 32 is connected and the side to which the support portion 33 is integrally provided, and is fixed to the valve seat plate 4 by screws on the side to which the piezoelectric element 32 is connected and the side where the support portion 33 is provided.

[0057] Further, in the actuator 3 of Embodiment 1, the support portion 33 has a constricted portion 331 in an intermediate portion extending in the second longitudinal direction, and is fixed to the valve seat plate 4 by screws using a mounting hole 38 provided between the constricted portion 331 and the base 31 on the side of the base 31 rather than the constricted portion 331.

[0058] Note that the base 31 only needs to be fixed to the valve seat plate 4 at least on the side to which one end of the piezoelectric element 32 is connected.

[0059] Here, the base portion 31 and the support portion 33 can be integrally formed by punching a metal material such as a stainless steel material including an Invar material, for example. If the base portion 31 and the support portion 33 are integrally formed by punching the metal material, the number of parts is reduced, and the assembly of the actuator 3 becomes easy.

[0060] Further, the base portion 31 and the support portion 33 can be formed of separate members, and the support portion 33 of the separate member can be attached to the base portion 31, so that the support portion 33 can be integrally provided on the base portion 31.

[0061] In the actuator 3 of Embodiment 1, the acting portion 34 can be formed of a lightweight material such as an aluminum material. If the acting portion 34 is formed of a lightweight material such as an aluminum material, it is preferable for displacing the acting portion 34. Further, the valve body 35 is made of rubber or the like, and preferably can be a lubricious rubber.

[0062] The actuator 3 can be connected between the base portion 31 and the acting portion 34 by a compression member 36. Although the piezoelectric element is liable to be damaged by a load in the tensile direction, if the compression member 36 is used to connect between the base portion 31 and the acting portion 34, the piezoelectric element 32 can be compressed in the first longitudinal direction, so that damage to the piezoelectric element 32 can be prevented.

[0063] FIG. 9 shows an explanatory diagram of the displacement waveform of the valve body in the actuator of Embodiment 1 of the present invention. The displacement waveform of the valve body 35 shown in FIG. 9 is obtained by measuring the displacement amount of the valve body 35 when a drive voltage is applied to the piezoelectric element 32 in the actuator 3 of Embodiment 1 shown in FIG. 8 and the piezoelectric element 32 is extended to drive the valve body 35 to open by a laser measuring instrument.

[0064] The experiment was conducted by applying a driving voltage to the piezoelectric element 32 based on the method described in the [Examples] of Japanese Patent Application Laid-Open No. 2017-160973. The experimental conditions are as follows. Each time condition of the input signal was set to an optimum value at which there are few ripples in the displacement waveform of the valve body. (1) Driving voltage: 72 V (2) Input signal: First pre-pulse time t1 = 0.06 ms First pause time t2 = 0.012 ms Second pre-pulse time t3 = 0.89 ms Second pause time t4 = 0.035 ms Main pulse time t5 = 0.003 ms (Power-on time of the piezoelectric element: 1 ms)

[0065] As shown in FIG. 9, in the actuator 3 of Embodiment 1, it can be confirmed that there is almost no ripple in the displacement waveform of the valve body 35. Therefore, by including the actuator 3 of Embodiment 1, the piezoelectric valve of the present invention can discharge the compressed gas from the gas discharge port in a stable state as compared with the piezoelectric valve of the prior invention.

[0066] <Embodiment 2> FIG. 10 shows an explanatory diagram of the actuator in Embodiment 2 of the present invention. In the actuator 3 of Embodiment 2, in the actuator 3 of the above Embodiment 1, the other end of the piezoelectric element 32 is connected to the acting portion 34 via a connecting portion 37 made of a material having a larger linear expansion coefficient than that of the support portion 33.

[0067] In the actuator 3 of Embodiment 2, since the other end of the piezoelectric element 32 is connected to the acting portion 34 via the connecting portion 37 made of a material having a larger linear expansion coefficient than that of the support portion 33, the influence of thermal expansion or thermal contraction of the piezoelectric element 32 due to temperature change can be reduced or eliminated.

[0068] In the actuator 3 of the second embodiment, the connecting portion 37 is provided integrally with the acting portion 34, and can be integrally formed by punching a metal material such as an aluminum material. If the acting portion 34 and the connecting portion 37 are integrally formed by punching a lightweight metal material such as an aluminum material, the number of parts is reduced, and the assembly of the actuator 3 becomes easy.

[0069] Also, the connecting portion 37 can be formed of a separate member such as an aluminum block, and the connecting portion 37 can be provided integrally with the acting portion 34 by attaching the connecting portion 37 of the separate member to the acting portion 34.

[0070] Note that by forming the connecting portion 37 of a separate member such as an aluminum block, one end portion of the piezoelectric element 32 can also be connected to the mounting surface of the base portion 31 via the connecting portion 37.

[0071] FIG. 11 shows an explanatory diagram of the displacement waveform of the valve body in the actuator of the second embodiment of the present invention. The displacement waveform of the valve body 35 shown in FIG. 11 is obtained by measuring the displacement amount of the valve body 35 when a driving voltage is applied to the piezoelectric element 32 in the actuator 3 of the second embodiment shown in FIG. 10 to expand the piezoelectric element 32 and drive the valve body 35 to open with a laser measuring instrument.

[0072] The experiment was conducted by applying a driving voltage to the piezoelectric element 32 based on the method described in [Examples] of Japanese Patent Application Laid-Open No. 2017-160973. The experimental conditions are as follows. Note that each time condition of the input signal was set to an optimum value in a state where there is little ripple generated in the displacement waveform of the valve body. (1) Driving voltage: 72 V (2) Input signal: First prepulse time t1 = 0.058 ms First pause time t2 = 0.008 ms Second prepulse time t3 = 0.877 ms Second pause time t4 = 0.046 ms Main pulse time t5 = 0.011 ms (Electrification time of piezoelectric element: 1 ms)

[0073] As shown in Fig. 11, in the actuator 3 of Embodiment 2, it can be confirmed that there is almost no ripple in the displacement waveform of the valve body 35, or even if there is ripple, the ripple is reduced compared to the actuator 3 of the prior invention shown in Fig. 7. Therefore, by including the actuator 3 of Embodiment 2, the piezoelectric valve of the present invention can discharge the compressed gas from the gas discharge port in a stable state compared to the piezoelectric valve of the prior invention.

[0074] <Embodiment 3> Fig. 12 shows an explanatory diagram of the actuator in Embodiment 3 of the present invention. The actuator 3 of Embodiment 3 is the actuator 3 of the above Embodiment 2, and includes a compression member 36 that is connected to the base portion 31 and the acting portion 34 and compresses the piezoelectric element 32 in the first longitudinal direction, and is located on the substantially central axis of the piezoelectric element 32 along the first longitudinal direction.

[0075] Since the actuator 3 of Embodiment 3 includes a compression member 36 that is respectively connected to the base portion 31 and the acting portion 34 and is located on the substantially central axis of the piezoelectric element 32 to compress the piezoelectric element 32 in the first longitudinal direction, a torsional force by the compression member 36 does not act on the piezoelectric element 32, and damage to the piezoelectric element 32 can be effectively prevented.

[0076] Fig. 13 shows an explanatory diagram of the displacement waveform of the valve body in the actuator of Embodiment 3 of the present invention. The displacement waveform of the valve body 35 shown in Fig. 13 is also the displacement amount of the valve body 35 when a driving voltage is applied to the piezoelectric element 32 in the actuator 3 of Embodiment 3 shown in Fig. 12 to extend the piezoelectric element 32 and drive the valve body 35 to open, and is measured by a laser measuring instrument.

[0077] The experiment was conducted by applying a driving voltage to the piezoelectric element 32 based on the method described in the [Examples] of Japanese Patent Application Laid-Open No. 2017-160973. The experimental conditions are as follows. Each time condition of the input signal was set to an optimum value such that there was little ripple in the displacement waveform of the valve body. (1) Driving voltage: 72V (2) Input signal: First prepulse time t1 = 0.054 ms First rest time t2 = 0.015 ms Second prepulse time t3 = 0.875 ms Second rest time t4 = 0.046 ms Main pulse time t5 = 0.01 ms (Power-on time of the piezoelectric element: 1 ms)

[0078] As shown in FIG. 13, also in the actuator 3 of Embodiment 3, it can be confirmed that there is almost no ripple in the displacement waveform of the valve body 35, or even if there is ripple, the ripple is reduced as compared with the actuator 3 of the prior invention shown in FIG. 7. Therefore, the piezoelectric valve of the present invention can also discharge the compressed gas from the gas discharge port in a stable state as compared with the piezoelectric valve of the prior invention by including the actuator 3 of Embodiment 3.

[0079] <Other Embodiments> In the actuator 3 in the above-described embodiment of the present invention, the displacement amount of the valve body 35 is adjusted by the length from the constricted portion 331 of the support portion 33 to the tip of the support portion 33 connected to the acting portion 34, and the discharge amount of the compressed gas discharged from the gas discharge port can be adjusted. That is, the piezoelectric valve of the present invention can increase the displacement amount of the valve body 35 and increase the discharge amount of the compressed gas discharged from the gas discharge port by using the actuator 3 including the support portion 33 having a long length from the constricted portion 331 to the tip. Further, the piezoelectric valve of the present invention uses the actuator 3 provided with the support portion 33 having a short length from the constricted portion 331 to the tip end portion, so that the displacement amount of the valve body 35 can be reduced, and the discharge amount of the compressed gas discharged from the gas discharge port can be decreased.

[0080] In the actuator 3 in the embodiment of the present invention described above, a plurality of mounting holes 38 are provided along the second longitudinal direction on the side of the base portion 31 rather than the constricted portion 331 in the support portion 33, and the support portion 33 can also be screwed to the valve seat plate 4 using at least one of the mounting holes 38. In the actuator 3 in the embodiment of the present invention described above, if a plurality of mounting holes 38 are provided along the second longitudinal direction on the side of the base portion 31 rather than the constricted portion 331 in the support portion 33, and the support portion 33 is screwed to the valve seat plate 4 using at least one of the mounting holes 38, then the displacement amount of the valve body 35 can be adjusted according to the position of the mounting hole 38 for fixing the support portion 33 to the valve seat plate 4, and the discharge amount of the compressed gas discharged from the gas discharge port can be adjusted.

[0081] The actuator 3 in the embodiment of the present invention described above can fill the gap formed between the base portion 31 and the acting portion 34 and between the piezoelectric element 32 and the support portion 33 with silicone, and fill the gap with the silicone.

[0082] In the actuator 3 in the embodiment of the present invention described above, when at least one of the one end portion or the other end portion of the piezoelectric element 32 is connected to the mounting surface of the base portion 31 or the acting portion 34 via a connecting portion 37 made of a material having a larger linear expansion coefficient than the support portion 33, the gap formed between the piezoelectric element 32 and the connecting portion 37 and the support portion 33 can be filled with silicone, and the gap can be filled with the silicone.

[0083] In the actuator 3 according to the embodiment of the present invention, if the gap formed between the base portion 31 and the working portion 34 and between the side where the piezoelectric element 32 extends in the first longitudinal direction and the side where the support portion 33 extends in the second longitudinal direction is filled with silicone, the ripple generated in the displacement waveform of the valve body 35 can be more effectively reduced.

[0084] Further, in the actuator 3 according to the embodiment of the present invention, the gap formed between the base portion 31 and the working portion 34 and between the piezoelectric element 32 and the support portion 33 can be made equidistant.

[0085] In the actuator 3 according to the embodiment of the present invention, if the gap formed between the base portion 31 and the working portion 34 and between the side where the piezoelectric element 32 extends in the first longitudinal direction and the side where the support portion 33 extends in the second longitudinal direction is made equidistant and the gap is filled with silicone, the filling of the silicone into the gap can be easily performed.

[0086] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and the configuration can be appropriately changed without departing from the scope of the invention.

Industrial Applicability

[0087] The piezoelectric valve of the present invention is extremely useful because it can reduce the ripple generated in the displacement waveform of the valve body and discharge the compressed gas from the gas discharge port in a stable state.

Explanation of Reference Numerals

[0088] 1 Piezoelectric valve 2 Valve body 3 Actuator 31 Base portion 311 Connecting member 32 Piezoelectric element 33 Support portion 331 Constricted portion 34 Working portion 35 valve body 36 compression member 37 connecting part 38 mounting hole 4 first valve seat plate 41 valve seat part 42 valve seat 43 attachment part 44 attachment part 45 discharge path 5 connector part 51 gas suction port 52 gas discharge port 6 cover body 61 wiring connector

Claims

1. An actuator for driving a valve body, a valve seat that contacts and separates from the valve body and a discharge passage, and a valve seat plate for fixing the actuator, a main body case for housing the valve seat plate, which is a piezoelectric valve comprising: The actuator includes: a base fixed to the valve seat plate, a piezoelectric element having one end connected to the mounting surface of the base and extending in a first longitudinal direction, a support portion provided integrally with the base and extending in a second longitudinal direction intersecting the first longitudinal direction alongside the piezoelectric element, an acting portion connected to the other end of the piezoelectric element and the tip of the support portion, and displacing in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element expands and contracts, a valve body provided on the side of the acting portion in the displacement direction thereof and driven by the displacement of the acting portion, The support portion has a constricted portion in an intermediate portion extending in the second longitudinal direction, and is fixed to the valve seat plate using a mounting hole provided between the constricted portion and the base, The main body case includes: a gas supply port to which compressed gas is supplied, a gas discharge port for discharging the compressed gas supplied from the gas supply port through the discharge passage of the valve seat plate by the separation between the valve body and the valve seat, A piezoelectric valve characterized by comprising the above.

2. A plurality of actuators for individually driving a plurality of valve bodies in parallel planes, a valve seat plate having a plurality of valve seats and discharge passages that individually contact and separate from the plurality of valve bodies, and for fixing the plurality of actuators, a main body case for housing the valve seat plate, which is a piezoelectric valve comprising: Each of the plurality of actuators includes: a base fixed to the valve seat plate, a piezoelectric element having one end connected to the mounting surface of the base and extending in a first longitudinal direction, a support portion provided integrally with the base and extending in a second longitudinal direction intersecting the first longitudinal direction alongside the piezoelectric element, an acting portion connected to the other end of the piezoelectric element and the tip of the support portion, and displacing in a displacement direction different from each of the first longitudinal direction and the second longitudinal direction as the piezoelectric element expands and contracts, a valve body provided on the side of the acting portion in the displacement direction thereof and driven by the displacement of the acting portion, The support portion has a constricted portion in an intermediate portion extending in the second longitudinal direction, and is fixed to the valve seat plate using a mounting hole provided between the constricted portion and the base, The main body case includes: A gas supply port to which a compressed gas is supplied, a plurality of gas discharge ports that individually discharge the compressed gas supplied from the gas supply port through the respective discharge paths of the valve seat plate by the separation of the plurality of valve elements and the plurality of valve seats, A piezoelectric valve characterized by comprising:

3. The piezoelectric valve according to claim 1 or 2, wherein the base portion is fixed to the valve seat plate at least on the side to which one end portion of the piezoelectric element is connected.

4. The piezoelectric valve according to any one of claims 1 to 3, wherein the displacement amount of the valve element is adjusted by the length from the constricted portion to the tip portion of the support portion.

5. The piezoelectric valve according to any one of claims 1 to 4, wherein at least one of the one end portion or the other end portion of the piezoelectric element is connected to the mounting surface or the acting portion of the base portion via a connecting portion made of a material having a larger linear expansion coefficient than that of the support portion.

6. The connecting portion is provided integrally with the acting portion, The piezoelectric valve according to claim 5, wherein the other end portion of the piezoelectric element is connected to the acting portion via the connecting portion made of a material having a larger linear expansion coefficient than that of the support portion.

7. The piezoelectric valve according to any one of claims 1 to 6, wherein the actuator is further provided with a compression member that is connected to each of the base portion and the acting portion and compresses the piezoelectric element in the first longitudinal direction.

8. The piezoelectric valve according to claim 7, wherein the actuator is provided with the compression member that is connected to each of the base portion and the acting portion and compresses the piezoelectric element in the first longitudinal direction on a substantially central axis of the piezoelectric element.

9. The piezoelectric valve according to any one of claims 1 to 8, wherein a gap formed between the base portion and the acting portion and between the piezoelectric element and the support portion is filled with silicone.

10. The piezoelectric valve according to any one of claims 1 to 9, wherein the gap formed between the base portion and the acting portion and between the piezoelectric element and the support portion is equally spaced, and the gap is filled with silicone.

Images