A piezoelectric actuator with a buffer layer.
Patent Information
- Authority / Receiving Office
- TR · TR
- Patent Type
- Utility models
- Current Assignee / Owner
- BOSCH SANAYI & TIC AS
- Filing Date
- 2024-06-28
- Publication Date
- 2026-06-22
Smart Images
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Abstract
Description
1 TARIFF A piezoelectric actuator with a buffer layer. TECHNICAL ASPECT OF THE INVENTION 5 The present application relates to an improvement in the technical field of piezoelectric actuators. Specifically, The present invention is based on a piezoelectric actuator, according to the prior part of the attached independent claim. It is related. BACKGROUND OF THE INVENTION Piezoelectric actuators, or piezo actuators for short, convert electrical energy into mechanical energy. Piezo actuators are devices for converting fuel in internal combustion engines. injectors, microfluidic applications, MEMS sensors, and many other technical fields - 15 They are used extensively. For example, some fuel injectors are a type of injection. To initiate the process, a length extension is created to lift the relevant valve needle. It incorporates a multi-layer piezo actuator for this purpose. For optimal energy transfer, copper (Cu) and silver (Ag) are commonly used as electrode materials. It is used in this way. Ag has the minimum resistance among metals. It is known that Ag can therefore provide maximum electrical conductivity. However, the use of Ag also brings with it several problems that need to be solved. The surfaces of the Ag electrodes can be considered to be in the form of silver oxide (Ag2O). When brought into contact with water, an anodic dissolution occurs, and Ag undergoes the following process: It ionizes from its oxide form according to the reaction: Ag2O + H2O 2Ag+ + 2OH- 30 Ag+ ions move from the anode to the corresponding cathode through the piezoelectric material. It is migrating; thus, it is degrading the performance of the relevant piezo actuator. In addition, Ag+ The arrival of ions at the cathode causes branching growth from the cathode to the anode; the result A short circuit occurs, rendering the piezo actuator inoperable. 35 2 On the other hand, some piezo actuators use silver / palladium (Ag / Pd) in the internal electrodes. alloys are used; in such cases, the migration of Ag+ is due to the migration of Pd in the alloy. It can be assumed that this is inversely proportional to the percentage. This information suggests that the migration of Ag+ ions... It appears to be beneficial in minimizing it; however, Pd is expensive. The material used causes an increase in the production cost for such piezo actuators. 5 is happening. EP 2 529 422 A1 refers to a material with one or more protective layers against moisture. The actuator is being disclosed. However, it has a longer service life and Providing a piezoelectric actuator that can be obtained at a low cost is still 10 It is requested. A BRIEF DESCRIPTION OF THE INVENTION The primary aim of the present invention is to overcome the aforementioned disadvantages of the previous technique. 15 Another aim of the present invention is to achieve a longer service life, a system with improved stability, improved robustness, low complexity, and low cost. The goal is to develop a piezoelectric actuator. The present application proposes the development of a piezoelectric actuator, as described in the attached independent claim. These objectives are achieved by its placement. In the context of the present application, piezoelectric an actuator, piezo actuator, or simply actuator can be used as such. According to the current invention, the piezoelectric actuator can be used with fuel-based internal combustion engines. It can be considered suitable for use in injectors. The actuator has a main axis 25 It includes a housing containing a piezoelectric material that extends along its length. The actuator, additionally Specifically, a first side of the piezoelectric material located parallel to the axis. It includes the outer electrode. The actuator additionally includes the first outer electrode of the piezoelectric material. It includes a second external electrode located on a second side opposite the first electrode. The actuator, Additionally, the piezoelectric material runs from the first outer electrode to the second outer electrode. It contains one or more primary inner electrodes that extend transversely from the axis through it. The actuator also uses piezoelectric material from the second outer electrode to the first outer electrode. one or more secondary internal electrodes extending parallel to the first internal electrodes It includes. 35 3 One or more primary internal electrodes and / or one or more secondary internal electrodes electrode, one or more electrodes partially covering the relevant first internal electrode and / or second internal electrode. This is achieved with a large number of buffer layers; thus: - an axial connection between a first inner electrode and a corresponding second inner electrode. The protrusion is covered by one or more buffer layers. 5 and / or - an axial connection between a second inner electrode and a corresponding first inner electrode. Its protrusion is covered by one or more buffer layers. In a possible first configuration, the first inner electrode is opposite to the corresponding second inner electrode. an axial projection of the second inner electrode on one side, with a buffer layer This is possible. In a possible version of the first configuration, the first inner electrode The portions outside the aforementioned axial projection are not provided with a buffer layer. It is possible. In a possible second configuration, the second internal electrode is opposite to the corresponding first internal electrode. an axial projection of the first inner electrode on one side, with a buffer layer This is possible. In a possible version of the second configuration, the second internal electrode The portions outside the aforementioned axial projection are not provided with a buffer layer. It is possible. 20 In a possible third configuration, the first inner electrode is opposite to the corresponding second inner electrode. an axial projection of the second inner electrode on one side and the corresponding second inner electrode An axial length of the first electrode on one side opposite the first inner electrode. The protrusion is provided by a buffer layer. A possible third configuration is 25 in this version, the aforementioned axial protrusions of the first inner electrode and the second inner electrode The remaining parts can be considered as not being provided by a buffer layer. In a possible fourth configuration, the first inner electrode is opposite to the corresponding second inner electrode. one side has an axial projection of the second inner electrode and the corresponding 30 of the second inner electrode. An axial length of the first electrode on one side opposite the first inner electrode. The protrusions are discrete, with the aforementioned protrusions being near and far, respectively, relative to the first outer electrode. This can be partially achieved with a buffer layer at the ends. The fourth configuration is possible. In one version, the aforementioned protrusions of the first inner electrode and the second inner electrode are mentioned. The portions remaining outside the separated ends are not provided with a buffer layer. 35 It is conceivable. 4 According to the present invention, in any configuration of the actuator, the buffer layer(s) are a strip, It can be in the form of tape, paste, or sheet metal. According to the present invention, in any configuration of the actuator, the piezoelectric material must be present. It is thought to contain a dielectric material. 5 According to the present invention, in any configuration of the actuator, the piezoelectric material must be present. It is thought to contain, or even more, dielectric ceramics. According to the present invention, in any configuration of the actuator, the first internal electrodes and / or 10 It is possible that the second inner electrodes contain silver. According to the present invention, any configuration of the actuator, one end of the housing one or more connected to the first and second outer electrodes respectively in the vicinity. 15 It is conceivable. The present invention also includes an actuator according to any of the configurations described herein. A fuel injector for internal combustion engines, which includes these components, is also presented. BRIEF DESCRIPTION OF THE FIGURES The sole purpose of the figures, the brief descriptions of which are given here, is to facilitate a better understanding of the present invention. to provide and, where a specification is not available, to define the scope of protection. It is not intended to define the context in which the scope mentioned will be interpreted. 25 Figure 1 shows a first possible configuration of the piezoelectric actuator according to the present invention. A schematic cross-sectional view is provided. Figure 2 shows a second possible configuration of the piezoelectric actuator according to the present invention. A cross-sectional view is provided. Figure 3 shows a third possible configuration of the piezoelectric actuator according to the present invention. A cross-sectional view is provided. 35 Figure 4 shows a fourth possible piezoelectric actuator according to the present invention. A cross-sectional view of its structure is given. Figure 5 shows a schematic of the primary configuration of the piezoelectric actuator according to the present invention. Detail D from Figure 1 is shown, illustrating a partial cross-sectional view. Figure 6 shows a schematic of the second configuration of the piezoelectric actuator according to the present invention. Detail E from Figure 2 is shown, illustrating the partial cross-section view. 5 Figure 7 shows a schematic of the third configuration of the piezoelectric actuator according to the present invention. The detail F from Figure 3 is shown, illustrating a partial cross-sectional view. Figure 8 shows a fourth configuration of the piezoelectric actuator according to the present invention, a 10 The G detail is shown in Figure 4, which depicts a schematic, partial cross-sectional view. DETAILED DESCRIPTION OF THE INVENTION Referring to the figures mentioned above, the present application includes a piezoelectric 15 The actuator (100) is presented: - a housing containing a piezoelectric material (10) that extends along a main axis (A). (1); - a piezoelectric material (10) located on one side of the first side parallel to the axis (A) first outer electrode (21); - on the second side of the piezoelectric material (10) opposite the first outer electrode (21) a second external electrode (22); 25 - through the piezoelectric material (10), transversely to the axis (A), from the first outer electrode (21) one or more first inner electrodes (31) extending toward the second outer electrode (22) And - from the piezoelectric material (10), the second outer electrode is parallel to the first inner electrode (31). one or more electrodes extending from the electrode (22) to the first outer electrode (21) second inner electrode (32). The first outer electrode (21) and one or more first inner electrodes extending from it 35 (31) is anodic, having a positive electric charge when in use and the second external electrode (22) and one or more second internal electrodes (32) extending from it 6 It is cathodic, having a negative electrical charge when in use. It can be considered that when in use, there is a first inner electrode (31) and a corresponding one. An electrical conduction between the second inner electrode (32) is from the cathode to the anode, in other words, The second inner electrode (32) is directed towards the corresponding first inner electrode (31). Accordingly, the first outer electrode (21) can be referred to as the outer anode; the first inner 5 The electrodes (31) can be referred to as the inner anodes and the second outer electrode (22) as the outer cathode. They can be referred to as; the second inner electrodes (32) can be referred to as inner cathodes. One or more first internal electrodes (31) and / or one or more second internal electrodes electrode (32), a 10 that partially covers the relevant first inner electrode (31) and / or second inner electrode (32). or is provided by more than one buffer layer (40); thus: - an axial projection of the corresponding second internal electrode (32) on a first internal electrode (31), is covered by one or more buffer layers (40) and / or - an axial projection of the first internal electrode (31) onto a second internal electrode (32), It is covered by one or more buffer layers (40). 15 The main axis (A) and the body (1), a first end (11) and a second end (12) far from the first end (11) It is thought that it extends between them. Liquid water, which can appear due to humidity, has a related electrical connection. It can advance by means of cables, in other words, the first end (1) of the body (1) (11) By means of an anode cable (61) and a cathode cable (62) that can be connected around it, the relevant external 20 progressing to the electrodes, in other words, to the first outer electrode (21) and the second outer electrode (22) and then it reaches the relevant internal electrodes, in other words, the first internal electrode (31) and It reaches the second inner electrode (32). The first inner electrode(s) (31) and the second inner axial on the opposite surfaces of one or both of the electrodes (32). Closing the protrusions limits anodic dissolution and / or dendrite formation or 25 It even prevents. According to the present invention, the actuator (100) thus, in the following chain of events It eliminates one or more steps: - the corresponding of the first inner electrode(s)(31) (in other words, the inner anode(s)) facing one side of the second inner electrode(s)(32) (in other words, the inner cathode(s)) Anodic dissolution on one side; 30 - Axial migration of silver ions towards the cathode(s) functioning together, - and the axial protrusion of the anodic dissolution zones of the inner anode(s). Dendritic growth on the cathode(s). Thus, according to the present invention, the functionality of the actuator (100) is a possible moisture advancement 35 It is protected even in this case. As a result, the present invention is protected with low production costs. together they provide a longer service life to the actuator (100). 7 In Figure 1, a first possible piezoelectric actuator (100) according to the present invention is shown. A schematic cross-sectional view of the structure is given. In Figure 5, a cross-section of the first structure is shown. The schematic, partial cross-sectional view, detail D from Figure 1 is shown. First The configuration is axial to the corresponding second inner electrode(s) (32) (in other words, cathodes). The first inner electrode(s) (31) (in other words, the anodes) overlapping on the sides 5 It eliminates anodic dissolution. In the first configuration, the first inner electrode (31) is opposite to the corresponding second inner electrode (32). An axial projection of the second internal electrode (32) on one side, with buffer layer (40) This criterion is provided. This criterion is the first internal 10 that cooperate with each other in terms of electrical transmission. to one, more than one or all of the electrode (31) and the corresponding second inner electrode (32) It can be applied to pairs (in other words, internal anode-cathode pairs). The first internal electrode (31) parts of the axial projection outside the mentioned (second of the first inner electrode (31) parts not corresponding to the inner electrode (32) are not provided by the buffer layer (40) It is conceivable. 15 In Figure 2, a second possible piezoelectric actuator (100) according to the present invention is shown. A schematic cross-sectional view of the structure is given. In Figure 6, a cross-section of the second structure is shown. The schematic, partial cross-sectional view, detail E from Figure 2 is shown. Second The configuration is axially 20° with the corresponding first inner electrode(s) (in other words, the anodes). Silver on the sides of the overlapping second inner electrode(s) (32) (in other words, the cathodes) It eliminates dendrite growth due to the arrival of its ions. In the second configuration, the second inner electrode (32) is opposite to the corresponding first inner electrode (31). An axial projection of the first inner electrode (31) on one side, with buffer layer (40) 25 This criterion is provided. This criterion is for the first internal components that cooperate with each other in terms of electrical transmission. to one, more than one or all of the electrode (31) and the corresponding second inner electrode (32) It can be applied to pairs (in other words, internal anode-cathode pairs). The second internal electrode (32) parts of the axial projection outside the mentioned projection with a buffer layer (40) It can be assumed that it has not been provided. 30 In Figure 3, a third possible piezoelectric actuator (100) according to the present invention is shown. A schematic cross-sectional view of its structure is given. In Figure 7, the third structure is shown. The detail F from Figure 3 is shown, illustrating a schematic, partial cross-sectional view. Third In the configuration, buffer 35 is used as a protective material on the inner anode (first inner electrode (31)). layer (40), through piezoelectric material (e.g. PZT ceramic) ions from the anode to prevent cathodic movement and to protect the inner cathode (second inner electrode (32)) 8 As a material, the buffer layer (40) prevents dendrite growth on the inner cathode. The third structure also eliminates the following: - axially with the corresponding second inner electrode(s) (32) (in other words, the cathodes). on the sides of the overlapping first inner electrode(s) (31) (in other words, the anodes) anodic dissolution and 5 - axially with the corresponding first inner electrode(s) (31) (in other words, the anodes) on the sides of the overlapping second inner electrode(s) (32) (in other words, the cathodes) Dendritic enlargement due to the arrival of silver ions. In the third configuration, the first inner electrode (31) is opposite to the corresponding second inner electrode (32) 10 an axial projection of the second internal electrode (32) on one side and the second internal electrode (32) On one side opposite the corresponding first inner electrode (31) is the first inner electrode (31) Axial protrusion is provided by the buffer layer (40). This criterion is electrical conduction. the first inner electrode (31) and the corresponding second inner electrode cooperate with each other in terms of to one, more than one or all pairs of electrodes (32) (in other words, internal anode-cathode 15 pairs) can be applied. The first inner electrode (31) and the second inner electrode (32) mentioned above parts outside the axial protrusions are not provided with a buffer layer (40) It is conceivable. In Figure 4, a fourth of the piezoelectric actuator (100) is possible according to the present invention. A schematic cross-sectional view of its structure is given. In Figure 8, the fourth structure is shown. The detail G from Figure 4 is shown, illustrating a schematic, partial cross-sectional view. The fourth configuration provides a higher electrical voltage between the cathodes and the corresponding anodes. With its transmission degree, it also partially eliminates the following: - axially 25 with the corresponding second inner electrode(s) (32) (in other words, cathodes). on the sides of the overlapping first inner electrode(s) (31) (in other words, the anodes) anodic dissolution and - axially with the corresponding first inner electrode(s) (31) (in other words, the anodes) on the sides of the overlapping second inner electrode(s) (32) (in other words, the cathodes) Dendritic growth upon the arrival of silver ions. 30 In the fourth configuration, the first inner electrode (31) is opposite to the corresponding second inner electrode (32). an axial projection of the second internal electrode (32) on one side and the second internal electrode (32) On one side opposite the corresponding first inner electrode (31) is the first inner electrode (31) The axial projection of the aforementioned 35 is near and far, respectively, with respect to the first outer electrode (21). This criterion is partially provided by a buffer layer (40) at the separate ends of the protrusions. The first inner electrode (31) and the corresponding electrode cooperate with each other in terms of electrical conduction. 9 to one, more than one or all pairs of the second inner electrode (32) (in other words, the inner anode- cathode pairs) can be applied. The first inner electrode (31) and the second inner electrode (32) The portions of the aforementioned protrusions that lie outside the aforementioned separate ends, the buffer It can be assumed that it is not provided by the layer (40). As explained above, the actuator (100) is connected to the first outer electrode (21) and the second outer electrode, respectively. one or more anode cables (61) that can be connected to the electrode (22) and one or can include a larger number of cathode wires (62). A structural material used for buffer layer(s) can be electrically conductive. and, for example, cathodic dissolution as water-impermeable (in other words, silver) It is thought that it was designed to prevent (ionization). Buffer layer (40) in the form of a strip, tape, paste, sheet, coating or metal coating It is possible. 15 Piezoelectric materials (10) include, for example, one or more dielectric ceramic materials. It can be considered as a dielectric material. The first inner electrodes (31) and / or the second inner electrodes (32) may contain silver. Similarly 20 In this way, the first outer electrode (21) and / or the second outer electrode (22) may contain silver. REFERENCE NUMBERS 1 body piezoelectric material 11 first end 5 12 second flight 21 first outer electrode 22 second outer electrode 31 first inner electrode 32 second inner electrode 10 40 buffer layers 61 anode cable 62 cathode cable 100 actuators A axis 15
Claims
11 REQUESTS 1. A piezoelectric material (10) that extends along a major axis (A) the housing (1); a first of the piezoelectric material (10) parallel to the axis (A) a first outer electrode (21) located on the side; the first 5 of the piezoelectric material (10) a second outer electrode (22) located on a second side opposite the outer electrode (21); from the piezoelectric material (10), the first outer electrode which is transverse to the axis (A) (21) one or more first inner electrodes extending toward the second outer electrode (22) through the electrode (31) and the piezoelectric material (10) to the first inner electrodes (31) one or 10 parallel electrodes extending from the second outer electrode (22) to the first outer electrode (21). fuel in internal combustion engines containing a greater number of second internal electrodes (32) It is a piezoelectric actuator (100) for use in injectors; its feature is one or more than one first internal electrode (31) and / or one or more second the inner electrode (32), the relevant first inner electrode (31) and / or the second inner electrode (32) partially provided by one or more buffer layers (40) that close; 15 like this: - on a first inner electrode (31), a corresponding second inner electrode (32) axial projection by one or more buffer layers (40) closure and / or - on a second inner electrode (32), a 20 on a corresponding first inner electrode (31) axial projection by one or more buffer layers (40) closure.
2. An actuator (100) according to claim 1, whose characteristic is that the first inner electrode (31) corresponds to An axial 25 of the second inner electrode (32) on one side opposite the second inner electrode (32). The protrusion is provided by the buffer layer (40).
3. An actuator (100) according to claim 2, and its characteristic is that the first inner electrode (31) is mentioned. parts of the axial projection not provided with a buffer layer (40) That is. 30 4. An actuator (100) according to claim 1, whose characteristic is that the second inner electrode (32) corresponds to On one side opposite the first inner electrode (31) is one of the first inner electrodes (31) The axial projection is provided by the buffer layer (40). 35 12 5. An actuator (100) according to claim 4, and its characteristic is that the second inner electrode (32) is mentioned. parts of the axial projection not provided with a buffer layer (40) It is the fact that.
6. An actuator (100) according to claim 1, whose characteristic is that the first inner electrode (31) corresponds to 5 an axial of the second inner electrode (32) on one side opposite to the second inner electrode (32). the protrusion of the second inner electrode (32) is opposite to the corresponding first inner electrode (31) an axial projection of the first inner electrode (31) on one side, with a buffer layer (40) is that it has been provided.
7. An actuator (100) according to claim 6, whose characteristic is; the first inner electrode (31) and the second inner The parts of the electrode (32) that are outside the aforementioned axial protrusions, buffer It is not provided by the layer (40).
8. An actuator (100) according to claim 1, whose characteristic is that the first inner electrode (31) corresponds to 15 an axial of the second inner electrode (32) on one side opposite to the second inner electrode (32). the protrusion of the second inner electrode (32) is opposite to the corresponding first inner electrode (31) an axial projection of the first inner electrode (31) on one side to the first outer electrode (21) buffers at the separate ends of the mentioned protrusions, which are near and far respectively. This is partly provided by the layer (40). 20 9. An actuator (100) according to claim 8, whose characteristic is that the first inner electrode (31) and the second inner the electrode (32) other than the mentioned protrusions of the mentioned separate ends The parts are not provided with a buffer layer (40).
10. An actuator (100) according to any of the requirements 1 to 9. The feature is that the buffer layer (40) is in the form of a strip, tape, paste or sheet. It is the fact that.
11. An actuator (100) according to any of the requirements 1 to 10 and 30 Its feature is that the piezoelectric material (10) contains a dielectric material.
12. An actuator (100) according to claim 11, whose characteristic is that a piezoelectric material (10) is either It also contains more dielectric ceramics. 35 13 13. An actuator (100) according to any of the requirements 1 to 12. its feature is that the first inner electrodes (31) and / or the second inner electrodes (32) are silver It includes.
14. An actuator (100) according to any of the requirements 1 to 13, 5 its feature is that the first end (11) of the body (1) is around the first outer electrode (21) and One or more anodes connected to the second outer electrode (22) respectively. It includes the cathode cable (61) and one or more cathode cables (62).
15. Containing the actuator (100) according to any of the requirements 1 to 14, 10 A fuel injector for internal combustion engines.