US5004945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric type actuator
Assignee: Denso Corp
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Filing: 1989-09-22
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Granted: 1991-04-02
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Expires: 2009-09-22
Abstract
Abstract According to the present invention there is provided a piezoelectric type actuator wherein a compressive force is exerted on a piezoelectric laminate, using a coil spring having a relatively small spring constant and a coned disc spring having a relatively large spring constant, the said compressive force being in the range of 4.0 to 50 in terms of the ratio of the spring constant of the coned disc spring to that of the coil spring. Under the above construction, the performance of the piezoelectric laminate is not deteriorated under any conditions during use, and the size of the piezoelectric type actuator can be reduced.
Inventors
- 👤 Masahiro Tomita
- 👤 Satoshi Hayashi
- 👤 Shinro Oda
- 👤 Akira Fujii
- 👤 Masayoshi Tanigawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:22
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/80; H10N30/88; H10N30/886; H10N30/50
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
173 words
A piezoelectric type actuator comprising: a piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates; a first spring means for exerting a compressive force on said piezoelectric laminate and having a relatively small spring constant and relatively long effective stroke; a second spring means for exerting a compressive force on said piezoelectric laminate and having a relatively large spring constant and relatively short effective stroke; said first spring means and second spring means being positioned in parallel with each other, and positioned so that an expanding stroke of said first spring means is equal to an expanding stroke of said second spring means when a length of said piezoelectric laminate after deforming is less than a maximum expanding length of said second spring means, so that the compressive force caused by said second spring means is dominant, and the compressive force caused by said first spring means becomes dominant when the length of said piezoelectric laminate after deforming exceeds the maximum expanding length of said second spring means,
Claim 2
Dependent Claim
173 words
A piezoelectric type actuator comprising: a piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates; a first spring means for exerting a compressive force on said piezoelectric laminate and having a relatively small spring constant and relatively long effective stroke; a second spring means for exerting a compressive force on said piezoelectric laminate and having a relatively large spring constant and relatively short effective stroke; said first spring means and second spring means being positioned in parallel with each other, and positioned so that an expanding stroke of said first spring means is equal to an expanding stroke of said second spring means when a length of said piezoelectric laminate after deforming is less than a maximum expanding length of said second spring means, so that the compressive force caused by said second spring means is dominant, and the compressive force caused by said first spring means becomes dominant when the length of said piezoelectric laminate after deforming exceeds the maximum expanding length of said second spring means,
Claim 3
Dependent Claim
35 words
A piezoelectric type actuator according to claim 1, wherein the ratio of a spring constant of said second spring means to that of said first spring means is in the range of 4.0 to 50.
Claim 4
Dependent Claim
27 words
A piezoelectric type actuator according to claim 1, wherein said first spring means is constituted by at least one of a coil spring and a metallic bellows.
Claim 5
Dependent Claim
30 words
A piezoelectric type actuator according to claim 1, wherein said second spring means is constituted by at least one of a coned disc spring, a wave spring and a bolt.
Claim 6
Dependent Claim
27 words
A piezoelectric type actuator according to claim 1, wherein said first spring means is a coil spring and said second spring means is a coned disc spring.
Claim 7
Dependent Claim
34 words
A piezoelectric type actuator according to claim 5, wherein a ratio of the spring constant of said coned disc spring to that of said coil spring is in the range of 4.09 to 50.
Claim 8
Dependent Claim
173 words
A piezoelectric type actuator comprising: a piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates; a first spring means for exerting a compressive force on said piezoelectric laminate; a second spring means for exerting a compressive force on said piezoelectric laminate; said first spring means and second spring means being positioned in parallel with each other, and positioned so that an expanding stroke of said first spring means is equal to an expanding stroke of said second spring means when said piezoelectric laminate has a length which is less than a maximum expanding length of said second spring means, thereby a compressive force caused by said second spring means is dominant, and a compressive force caused by said first spring means becomes dominant when the deforming length of said piezoelectric laminate exceeds the maximum expanding length of said second spring means; and a ratio of a spring load of said first spring means to that of said second spring means being in the range of 1/3 to 1/4.
Claim 9
Dependent Claim
173 words
A piezoelectric type actuator comprising: a piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates; a first spring means for exerting a compressive force on said piezoelectric laminate; a second spring means for exerting a compressive force on said piezoelectric laminate; said first spring means and second spring means being positioned in parallel with each other, and positioned so that an expanding stroke of said first spring means is equal to an expanding stroke of said second spring means when said piezoelectric laminate has a length which is less than a maximum expanding length of said second spring means, thereby a compressive force caused by said second spring means is dominant, and a compressive force caused by said first spring means becomes dominant when the deforming length of said piezoelectric laminate exceeds the maximum expanding length of said second spring means; and a ratio of a spring load of said first spring means to that of said second spring means being in the range of 1/3 to 1/4.
Claim 10
Dependent Claim
26 words
A piezoelectric actuator according to claim 7, wherein said first spring means is constituted by at least one of a coil spring and a metallic bellows.
Claim 11
Dependent Claim
30 words
A piezoelectric type actuator according to claim 7, wherein said second spring means is constituted by at least one of a coned disc spring, a wave spring and a bolt.
Claim 12
Dependent Claim
27 words
A piezoelectric type actuator according to claim 7, wherein said first spring means is a coil spring and said second spring means is a coned disc spring.
Claim 13
Dependent Claim
189 words
A piezoelectric type actuator comprising: a piston comprising a piezoelectric laminate and a holder member which receives said piezoelectric laminate slidably therein, said piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates, said holder member having a bottomed portion formed at one end thereof and also having a flange formed at an opening portion of the other end thereof; a first body which receives at least said flange-side end face of said piston slidably therein; a second body which receives said bottomed portion-side end face of said piston slidably therein, said second body having a shoulder portion opposed to said flange of said holder member; a first spring means for exerting a compressive force on said piezoelectric laminate, said first spring means being interposed between said shoulder portion of said second body and said flange of said holder member and having a relatively small spring constant; and a second spring means for exerting a compressive force on said piezoelectric laminate, said second spring being interposed between said second body and said bottomed portion of said holder member and having a relatively large spring constant.
Claim 14
Dependent Claim
189 words
A piezoelectric type actuator comprising: a piston comprising a piezoelectric laminate and a holder member which receives said piezoelectric laminate slidably therein, said piezoelectric laminate comprising alternately superimposed piezoelectric plates as piezoelectric elements and metallic electrode plates, said holder member having a bottomed portion formed at one end thereof and also having a flange formed at an opening portion of the other end thereof; a first body which receives at least said flange-side end face of said piston slidably therein; a second body which receives said bottomed portion-side end face of said piston slidably therein, said second body having a shoulder portion opposed to said flange of said holder member; a first spring means for exerting a compressive force on said piezoelectric laminate, said first spring means being interposed between said shoulder portion of said second body and said flange of said holder member and having a relatively small spring constant; and a second spring means for exerting a compressive force on said piezoelectric laminate, said second spring being interposed between said second body and said bottomed portion of said holder member and having a relatively large spring constant.
Claim 15
Dependent Claim
35 words
A piezoelectric type actuator according to claim 11, wherein the ratio of the spring constant of said second spring means to that of said first spring means is in the range of 4.0 to 50.
Claim 16
Dependent Claim
27 words
A piezoelectric type actuator according to claim 8, wherein said first spring means includes a coil spring and said second spring means includes a coned disc spring.
Claim 17
Dependent Claim
34 words
A piezoelectric type actuator according to claim 13, wherein the ratio of the spring constant of said coned disc spring to that of said coil spring is in the range of 4.0 to 50.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |