JP2016007099A - Energy conversion system - Google Patents

Energy conversion system Download PDF

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JP2016007099A
JP2016007099A JP2014127063A JP2014127063A JP2016007099A JP 2016007099 A JP2016007099 A JP 2016007099A JP 2014127063 A JP2014127063 A JP 2014127063A JP 2014127063 A JP2014127063 A JP 2014127063A JP 2016007099 A JP2016007099 A JP 2016007099A
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cam
torque
piezoelectric
follower
drive
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JP6265059B2 (en
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嗣治 上林
Tsuguji Kamibayashi
嗣治 上林
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株式会社村田製作所
Murata Mfg Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To reduce a combined value of torque that is caused by a plurality of cams and acts, as reactive force, on a drive member.SOLUTION: An energy conversion system comprises: cam mechanisms 1, 2; a subordinate joint mechanism 10 that includes a piezoelectric element 11 for receiving a load caused by rotation of the cam mechanism 1 and gives reactive force to the cam mechanism 1 when the piezoelectric element 11 receives the load; a subordinate joint mechanism 20 that includes a compression member 21 for receiving a load caused by rotation of the cam mechanism 2 and gives reactive force to the cam mechanism 2 when the compression member 21 receives the load; and a drive member 50 for rotating the cam mechanisms 1, 2. When the drive member rotates the cam mechanisms 1, 2, the drive member receives first torque from the subordinate joint mechanism 10 through the cam mechanisms 1 and second torque from the subordinate joint mechanism 20 through the cam mechanisms 2, where the first torque and the second torque act in the same period. Waveforms of the first torque and the second torque acting on the drive member during the drive member's relative displacement have phases reverse to each other and the absolute values of displacement equal to each other.

Description

  The present invention relates to an energy conversion system that generates electric power by applying a load to a piezoelectric element using a cam.

  International Publication No. 2013/069516 (Patent Document 1) discloses a piezoelectric power generation element including a cam, a piezoelectric element, and a slide member. As the slide member moves, the slide member rotates the cam. A load is periodically applied to the piezoelectric element by the rotation of the cam, and electric power is generated by the piezoelectric effect of the piezoelectric element.

International Publication No. 2013/069516

  When the cam is rotated using a driving member such as a slide member, a load is applied to the piezoelectric element by the operation of the cam. On the other hand, the reaction force corresponding to the load applied to the piezoelectric element acts as torque on the driving member. The torque acting on the drive member may act as a resistance to the operation of the drive member. When a plurality of cams are used, torque acting on the drive member by the plurality of cams acts on the drive member in a combined state. It is preferable that the combined value of the torque acting on the drive member by the plurality of cams is small.

  An object of this invention is to provide the energy conversion system which can make small the synthetic value of the torque which acts as a reaction force on a drive member with a some cam.

  An energy conversion system according to the present invention is an energy conversion system that generates electric power by applying a load to a piezoelectric element, and includes a first cam mechanism, a second cam mechanism, and a piezoelectric element that receives a load by the rotation of the first cam mechanism. A first follower mechanism that applies a reaction force to the first cam mechanism as the piezoelectric element receives a load, and a compression member that receives a load by the rotation of the second cam mechanism, As the compression member receives a load, the second follower mechanism that applies a reaction force to the second cam mechanism and the relative movement with respect to the first cam mechanism and the second cam mechanism A drive member that rotates the first cam mechanism and the second cam mechanism. When the drive member rotates the first cam mechanism and the second cam mechanism, the drive member includes the first cam mechanism and the second cam mechanism. The first torque received from the follower mechanism through the first cam mechanism and the second torque received from the second follower mechanism through the second cam mechanism act at the same cycle, and the drive member is moved to a predetermined level. The waveform of the first torque and the waveform of the second torque that act on the drive member during the relative movement by the distance are opposite in phase and have the same absolute value of displacement.

Preferably, the compression member is a piezoelectric element.
Preferably, the arbitrary coefficient is A, and the cams provided in both the first cam mechanism and the second cam mechanism have n (n = 1, 2, 3, 4... ), The position of the cam in the rotational direction is r, and the average radius of the cam is R avg , the function f (r) is expressed by the following equation (1).

When the spring constant of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member is k, the rotation of the cam is expressed by the following equation (2). displacement y r are represented in the angle r.

  The cam curve L1 of the cam is expressed by the following equation (3).

Preferably, the arbitrary coefficient is A, and the cams provided in both the first cam mechanism and the second cam mechanism have n (n = 1, 2, 3, 4... ), Where r is the position in the rotational direction of the cam, and R avg is the average radius of the cam, the function f (r) is expressed by the following equation (4).

When the spring constant of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member is k, the rotation of the cam is expressed by the following equation (5). displacement y r are represented in the angle r.

  The cam curve L2 of the cam is expressed by the following equation (6).

Preferably, the arbitrary coefficient is A, and the cams provided in both the first cam mechanism and the second cam mechanism have n (n = 1, 2, 3, 4... ), The position of the cam in the rotation direction is r, and the average radius of the cam is R avg , the function f (r) is expressed by the following equation (7).

When the spring constants of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member are k, the rotation of the cam is expressed by the following equation (8). displacement y r are represented in the angle r.

  The cam curve L3 of the cam is expressed by the following equation (9).

  According to each configuration described above, the combined value of the torque acting as a reaction force on the drive member by the plurality of cams can be reduced.

1 is a plan view showing an energy conversion system in Embodiment 1. FIG. 2 is a plan view showing a cam mechanism and a follower mechanism provided in the energy conversion system in Embodiment 1. FIG. FIG. 3 is a perspective view showing an exploded state of a cam mechanism and a follower mechanism provided in the energy conversion system in the first embodiment. 5 is a plan view for explaining the operation of the energy conversion system in Embodiment 1. FIG. 3 is a graph showing a cam curve of a cam employed in the energy conversion system in Embodiment 1, and a first torque, a second torque, and a combined torque that act on a drive member. It is a 1st model figure which shows the cam and follower mechanism which are used in order to calculate the 1st structural example of a cam curve. It is a 2nd model figure which shows the cam and follower mechanism which are used in order to calculate the 1st structural example of a cam curve. It is a 3rd model figure which shows the cam and follower mechanism which are used in order to calculate the 1st structural example of a cam curve. It is a 4th model figure which shows the cam and follower mechanism which are used in order to calculate the 1st structural example of a cam curve. FIG. 10 is a plan view for explaining the operation of the energy conversion system in the second embodiment. 6 is a model diagram showing a cam and a follower mechanism of an energy conversion system according to Embodiment 2. FIG. It is a graph which shows the 1st torque which acts on a drive member when the 2nd example of composition of a cam curve, and the 2nd example of composition of a cam curve are adopted, and synthetic torque. It is a top view which shows the 1st cam shape (n = 1) based on the 2nd structural example of a cam curve. It is a top view which shows the 2nd cam shape (n = 3) based on the 2nd structural example of a cam curve. It is a top view which shows the 3rd cam shape (n = 5) based on the 2nd structural example of a cam curve. It is a graph which shows the 1st torque which acts on a drive member when the 3rd example of composition of a cam curve, and the 3rd example of composition of a cam curve are adopted, and synthetic torque. It is a graph which shows the 1st torque and 2nd torque which act on a drive member when the 4th example of a cam curve and the 4th example of a cam curve are adopted. It is a graph for demonstrating contrast with actual measurement torque and calculation torque based on the 2nd example of composition.

  Hereinafter, embodiments will be described with reference to the drawings. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

[Embodiment 1]
(Energy conversion system 100)
FIG. 1 is a diagram showing an energy conversion system 100 according to the first embodiment. The energy conversion system 100 generates power when a load is applied to the piezoelectric elements 11 and 21. Specifically, the energy conversion system 100 includes a cam mechanism 1 (first cam mechanism), a cam mechanism 2 (second cam mechanism), a follower mechanism 10 (first follower mechanism), and a follower mechanism 20. (Second follower mechanism) and a drive member 50 are provided. The follower mechanism 10 includes a piezoelectric element 11 and linearly follows the cam mechanism 1. The follower mechanism 20 includes a piezoelectric element 21 and linearly follows the cam mechanism 2.

  The drive member 50 can move relative to the cam mechanisms 1 and 2. For example, the drive member 50 is attached to a sliding door. The cam mechanisms 1 and 2 are attached to the door frame together with the follower mechanisms 10 and 20. As the door moves, the drive member 50 moves in the direction of the arrow AR, whereby the cams 3 and 4 of the cam mechanisms 1 and 2 rotate. The rotational movements of the cams 3 and 4 are converted into energy for compressing the piezoelectric elements 11 and 21 by the follower mechanisms 10 and 20.

  The piezoelectric elements 11 and 21 that have received the compression energy (load) generate power by the piezoelectric effect (details will be described later). That is, the mechanical energy applied to the drive member 50 is converted into electrical energy by the piezoelectric elements 11 and 21. A wireless communication unit (not shown) is driven by the power generation of the piezoelectric elements 11 and 21, and the open / closed state of the door can be detected at a remote place.

(Cam mechanism 1 and follower mechanism 10)
FIG. 2 is a plan view showing the cam mechanism 1 and the follower mechanism 10. FIG. 3 is a perspective view showing the cam mechanism 1 and the follower mechanism 10 in an exploded state. The follower mechanism 10 will be described with reference to FIGS. For convenience of illustration, in FIG. 2 and FIG. 3, the drive member 50 is partially illustrated, and the rack tooth 51 side of the drive member 50 is illustrated, but the rack tooth 52 of the drive member 50 is illustrated. The side (see FIG. 1) is not shown.

  As shown in FIGS. 1 to 3, the follower mechanism 10 that follows the cam mechanism 1 includes a piezoelectric element 11, a support 12, and a protrusion 15. The piezoelectric element 11 has a quadrangular prism-shaped piezoelectric body and a pair of electrodes, and surfaces 11A and 11B are formed at both ends in the longitudinal direction. The piezoelectric body of the piezoelectric element 11 is made of, for example, lead zirconate titanate (PZT).

  The support 12 includes a stopper 13 and a lever 14, which are integrally formed. The stopper 13 has a contact portion 13A. The contact portion 13 </ b> A is in contact with the surface 11 </ b> A of the piezoelectric element 11. The cam mechanism 1 is rotatably attached to the stopper 13. The lever 14 includes a connecting portion 14A, a contact portion 14B, and a displacement portion 14C. The lever 14 is made of a highly rigid metal or ceramic. The connection portion 14A connects the contact portion 14B and the displacement portion 14C. The contact portion 14B has a contact portion 14D. The contact portion 14 </ b> D is in contact with the surface 11 </ b> B of the piezoelectric element 11.

  The cam mechanism 1 includes a cam 3 and a gear 5. In plan view, the cam 3 of the present embodiment has a substantially elliptical shape. The cam 3 is integrated with the gear 5, and the cam 3 and the gear 5 rotate integrally. The gear 5 is arranged to mesh with the rack teeth 51 of the drive member 50. The protruding portion 15 has a cylindrical shape and is fixed to the displacement portion 14 </ b> C of the lever 14. The cam 3 and the protrusion 15 are arranged so as to contact each other. From the viewpoint of suppressing deformation and improving wear resistance, the cam 3 and the protrusion 15 may be formed of POM, metal, or the like, and the surface thereof may be processed to improve slidability.

  When the drive member 50 reciprocates in the direction of the arrow AR (FIG. 1), the rack teeth 51 move relative to the gear 5. The gear 5 and the cam 3 rotate integrally. As the gear 5 and the cam 3 rotate, the distance between the central axis of the cam 3 and the protrusion 15 changes periodically, and the displacement portion 14C swings. When the displacement portion 14 </ b> C swings, the lever 14 swings in the rotation direction around the rotation shaft 16 positioned near the connection portion between the stopper 13 and the lever 14. The contact portion 14 </ b> D is displaced relative to the contact portion 13 </ b> A in the longitudinal direction of the piezoelectric element 11. The contact portion 14D presses the surface 11B of the piezoelectric element 11, and the piezoelectric element 11 is repeatedly compressed.

  That is, the piezoelectric element 11 receives a load due to the rotation of the cam 3 of the cam mechanism 1, and the piezoelectric element 11 generates power by the piezoelectric effect. A load is periodically applied to the piezoelectric element 11 by an amount corresponding to the amount of movement of the driving member 50, and the electric power generated in the piezoelectric element 11 is stored in a capacitor or the like (not shown).

(Cam mechanism 2 and follower mechanism 20)
Referring back to FIG. 1, the follower mechanism 20 that follows the cam mechanism 2 includes a piezoelectric element 21, a support 22, and a protrusion 25. The cam mechanism 2 and the follower mechanism 20 have substantially the same configurations as the cam mechanism 1 and the follower mechanism 10, respectively. The cam mechanism 2, the piezoelectric element 21, the support 22, and the protrusion 25 correspond to the cam mechanism 1, the piezoelectric element 11 of the follower mechanism 10, the support 12, and the protrusion 15, respectively. The cam mechanism 2 includes a cam 4 and a gear 6. In plan view, the cam 4 of the present embodiment has a substantially elliptical shape. The cam 3 of the follower mechanism 10 and the cam 4 of the follower mechanism 20 have the same shape.

  When the drive member 50 reciprocates, the rack teeth 52 move relative to the gear 6. The gear 6 and the cam 4 rotate integrally. As the gear 6 and the cam 4 rotate, the distance between the central axis of the cam 4 and the protrusion 25 changes, and the piezoelectric element 21 is repeatedly compressed. That is, the piezoelectric element 21 receives a load due to the rotation of the cam 4 of the cam mechanism 2, and the piezoelectric element 21 generates power by the piezoelectric effect. A load is periodically applied to the piezoelectric element 21 by an amount corresponding to the amount of movement of the driving member 50, and the electric power generated in the piezoelectric element 21 is stored in a capacitor or the like (not shown).

(First torque / Second torque)
In the present embodiment, two cams 3 and 4 are provided so as to correspond to the two piezoelectric elements 11 and 21, respectively. As the rack teeth 51, 52 of the drive member 50 move relative to the cams 3, 4, the cams 3, 4 rotate. As the cams 3 and 4 rotate, a periodic load is applied to the piezoelectric elements 11 and 21 of the follower mechanisms 10 and 20. On the other hand, the follower mechanisms 10 and 20 (protrusions 15 and 25) exert a reaction force on the cam mechanisms 1 and 21 as the piezoelectric elements 11 and 21 receive a load due to the rotation of the cam mechanisms 1 and 2. Give. The reaction force periodically acts on the drive member 50 as torque.

  When the drive member 50 rotates the cams 3 and 4 of the cam mechanisms 1 and 2, the drive member 50 receives a first torque (arrow DR3 in FIG. 4) received from the follower mechanism 10 (protrusion 15) through the cam mechanism 1. ) And the second torque (arrow DR4 in FIG. 4) received from the follower mechanism 20 through the cam mechanism 2 operate in the same cycle. Here, the same cycle means that the cycle of the first torque and the cycle of the second torque are the same cycle. The waveform of the first torque (see FIG. 5) and the waveform of the second torque (see FIG. 5) that act on the drive member 50 while the drive member 50 is relatively moved by a predetermined distance are opposite in phase. The absolute values of the displacements (torques) are the same (see FIGS. 5, 12, 16, and 17).

  With reference to FIG. 4 and FIG. 5, the above configuration will be described more specifically. FIG. 4 is a plan view showing the state of the energy conversion system 100 at a certain point in time when the drive member 50 is moving in the direction of the arrow AR1. FIG. 4 schematically shows the gears 5 and 6. When the drive member 50 moves in the direction of arrow AR1, the cam 3 of the cam mechanism 1 rotates in the direction of arrow DR1, and the cam 4 of the cam mechanism 2 rotates in the direction of arrow DR2. The cams 3 and 4 are configured such that when the apex (top dead center) of the cam 3 is in contact with the protrusion 15, the lower point (bottom dead center) of the cam 4 is in contact with the protrusion 25. . At the time shown in FIG. 4, the protrusion 15 is in sliding contact with the peripheral surface of the cam 3 so that the cam 3 is directed from the apex of the cam 3 to the lower point, whereas the cam 4 is apex from the lower point of the cam 4. The projecting portion 25 is in sliding contact with the circumferential surface of the cam 4 so as to face the head.

  As for the cam 3, the projecting portion 15 is in sliding contact with the peripheral surface of the cam 3 so as to go from the apex to the lower point. Therefore, the direction of the force in the rotational direction that the cam 3 receives from the projecting portion 15 is the direction indicated by the arrow DR 3. . The direction of the arrow DR3 is the same as the direction in which the cam 3 rotates by the movement of the drive member 50 in the direction of the arrow AR1, that is, the direction of the arrow DR1. The force shown in the direction of the arrow DR3 is transmitted as torque (first torque shown in FIG. 5) to the driving member 50 through the gear 5, and acts in the same direction as the direction in which the driving member 50 moves.

  As for the cam 4, the protrusion 25 is in sliding contact with the peripheral surface of the cam 4 from the lower point toward the apex, so the direction of the force in the rotational direction that the cam 4 receives from the protrusion 25 is the direction indicated by the arrow DR 4. . The direction of the arrow DR4 is opposite to the direction in which the cam 4 is rotated by the movement of the drive member 50 in the direction of the arrow AR1, that is, the direction of the arrow DR2. The force shown in the direction of the arrow DR4 is transmitted as torque (second torque shown in FIG. 5) to the driving member 50 through the gear 6, and acts in the direction opposite to the direction in which the driving member 50 moves.

  In the cams 3 and 4, operations opposite to the above are performed at different timings. That is, when the drive member 50 moves, the cams 3 and 4 rotate synchronously (rotate while maintaining the period and phase). When the driving member 50 is moving, the torque received by the driving member 50 from the cams 3 and 4 includes a force acting in the moving direction of the driving member 50 and a force acting in the direction opposite to the moving direction of the driving member 50. And are included.

FIG. 5 is a diagram showing the relationship between the cam curves of the cams 3 and 4, the rotation angle of the cams 3 and 4, and the magnitude of torque received by the drive member 50 as the cams 3 and 4 rotate. The cams 3 and 4 have the same cam curve. The cam curve of the cams 3 and 4 here is equal to the relationship between the rotation angle of the cams 3 and 4 and the displacement y r (see FIG. 6) of the protrusions 15 and 25 of the follower mechanisms 10 and 20. The torque received by the drive member 50 acts in a direction orthogonal to a line passing through the center of the rotation shaft of the cams 3 and 4 and the center of the projections 15 and 25.

  In FIG. 5, the torque received by the drive member 50 is a positive force generated when the protrusions 15 and 25 are moving in the direction of climbing the ridge of the cam, and the protrusion moves in the direction of descending the ridge of the cam. The force that is generated when you are doing is-. The torque received by drive member 50 is the force indicated by arrows DR3 and DR4 in FIG. The absolute values of the forces (torques) indicated by arrows DR3 and DR4 are the same.

  As shown in FIG. 5, the first torque waveform (see FIG. 5) and the second torque acting on the drive member 50 while the drive member 50 relatively moves by a predetermined distance (while the cam rotates by 360 °). The torque waveform (see FIG. 5) has the opposite phase, and the absolute value of the displacement (torque) is the same. FIG. 5 also shows the relationship between the combined torque received by the drive member 50 as the cams 3 and 4 rotate and the rotation angle of the cams 3 and 4.

  The first torque received by the drive member 50 with the rotation of the cam 3 and the second torque received by the drive member 50 with the rotation of the cam 4 are in a mutually canceling relationship. Therefore, the maximum value of the torque acting on the drive member 50 as the combined torque is sufficiently smaller than the maximum value of the torque received by the drive member 50 by the individual cams 3 and 4 (for example, 5% or less). Since the peak-to-peak torque for driving the drive member 50 can be reduced, the amount of power generation per torque input to the drive member 50 can be increased. In other words, the power generation efficiency per piezoelectric element can be improved.

  The mechanical energy stored when the follower mechanism 10 compresses the piezoelectric element 11 is utilized when the follower mechanism 20 compresses the piezoelectric element 21. In other words, when the load is applied to the piezoelectric element 11, the energy stored while the load is applied to the piezoelectric element 21 is used, and when the load is applied to the piezoelectric element 21, the load is applied to the piezoelectric element 11. Since the energy stored during the period of giving is used, the energy use efficiency is good.

  Therefore, energy for applying a load to the piezoelectric elements 11 and 21 can be reduced. In order to drive the drive member 50, the energy consumed when the piezoelectric elements 11 and 21 convert energy, the energy consumed when the piezoelectric elements 11 and 21 are deformed, and the cams 3 and 4 It is only necessary to apply a drive having a necessary minimum drive amount such as replenishment by the amount of energy consumed when friction or heat between the protrusions 15 and 25 is generated.

  In the first embodiment, the follower mechanisms 10 and 20 (cams 3 and 4) are arranged so as to face each other across the drive member 50. However, the follower mechanisms 10 and 20 (cams 3 and 4) are arranged. May be arranged at positions shifted in the moving direction of the drive member 50, or two may be arranged side by side on the rack tooth 51 side. Even with these arrangements, the same operations and effects as described above can be obtained.

  In the first embodiment, the follower mechanism 10 includes the piezoelectric element 11, and the follower mechanism 20 includes the piezoelectric element 21. If the piezoelectric element 11 has a power generation function, the piezoelectric element 21 does not necessarily need to function as a piezoelectric element. Even when the piezoelectric element 21 is composed of a member (compression member) that does not have a power generation function, by configuring the member to have a spring constant similar to that of the piezoelectric element 11, the first torque Regarding the waveform (see FIG. 5) and the waveform of the second torque (see FIG. 5), the phases can be reversed, and the absolute values of the displacement (torque) can be the same. Also in this case, the same operations and effects as described above can be obtained.

[First configuration example of cam curve]
Here, a description will be given of a first configuration example of the cam curves of the cams 3 and 4 that can be preferably implemented when the idea of the first embodiment is adopted. When the cam curve of the first configuration example (see FIG. 5) is adopted, a torque curve having a sinusoidal shape for one cycle appears when the cam rotates 360 °. Specifically, let A be an arbitrary coefficient. Factor A is a value corresponding to the vibration amplitude of the displacement y r of the projections 15 and 25 of the follower mechanism 10 and 20. Next, with respect to the cams 3 and 4 provided in both the cam mechanism 1 and the cam mechanism 2, the number of cam peaks is n (n = 1, 2, 3, 4...), And the cam rotation direction. Let r be the position at and the average radius of the cam be R avg . These values are values common to the cams 3 and 4 (same values). The function f (r) is expressed by the following equation (1).

When the spring constants of both the follower mechanism 10 including the piezoelectric element 11 and the follower mechanism 20 including the piezoelectric element 21 are k, the position r in the rotation direction of the cam is expressed by the following equation (2). displacement y r is expressed upon.

  By using the above equations (1) and (2), the cam curve L1 of the cams 3 and 4 can be expressed by the following equation (3).

Referring to FIG. 6, the above formulas (1) to (3) are calculated based on the following concept. That is, it is assumed that the cam mechanism 1 (cam 3) and the follower mechanism 10 (projection 15) are modeled as shown in FIG. Here, the number n of the peaks of the cam 3 is 1, the minimum radius of the cam 3 is R min, and the maximum radius of the cam 3 is R min + y r (max) . The cam 3 rotates in the direction of arrow A.

  Referring to FIG. 7, as in the case of the first embodiment described above, considering the torque acting on drive member 50, a model as shown in FIG. 7 is obtained. That is, the follower mechanism 10 and the follower mechanism 20 are disposed so as to face each other with the drive member 50 (not shown) interposed therebetween. The follower mechanism 10 and the protrusion 15 can be regarded as being displaced (moved) by the cam curve 1S moving in the direction of the arrow A1, and the follower mechanism 20 and the protrusion 25 are cam curves moving in the direction of the arrow A2. It can be regarded as being displaced (moved) by 2S.

  Referring to FIG. 8, when the pressure angle of the protrusion 15 with respect to the cam curve 1S is ψ, of the force F1 that the protrusion 15 receives from the cam 3 (cam curve 1S), the protrusion 15 (piezoelectric element 11), etc. The force F1y provided for the displacement is F1cosψ. Similarly, when the pressure angle of the protrusion 25 with respect to the cam curve 2S is ψ, the protrusion 25 is subjected to displacement of the protrusion 25 (piezoelectric element 21) and the like out of the force F2 that the protrusion 25 receives from the cam 4 (cam curve 2S). The force F2y is F2cosψ. Here, the friction generated between the cam curves 1S and 2S and the protrusions 15 and 25 can be ignored by providing sufficient lubricating means between them.

Based on the above, when calculating a cam curve having a single sinusoidal waveform between 360 °, such as the first torque and the second torque shown in FIG. ).
T = k · {tan ψ · y r · (R min + y r )} = A · sin (n · θ) (A)
Referring to FIG. 9, since the pressure angle is represented by ψ = dy / dr, the relationship of θ = r / R avg is established in the above formula (A). Here, it is assumed that the relationship of R avg = R min + y r (max) is established. Since y r is a function of r, the above equations (1) to (3) can be obtained by solving the above equation (A). When the above formulas (1) to (3) are applied to the idea of the first embodiment and an experiment by simulation is performed, it is found that the combined value of torque acting as a reaction force on the driving member can be sufficiently reduced. It was.

[Embodiment 2]
With reference to FIG. 10, energy conversion system 100A in the second embodiment will be described. In the first embodiment (see FIG. 1), the driving member 50 reciprocates. In contrast, in the energy conversion system 100A of the present embodiment, the drive member 50A supported by the central shaft 55 rotates and moves relative to the cam mechanisms 1 and 2. The drive member 50A has a gear 56 on the outer periphery, and is configured to rotate in conjunction with, for example, a rotating door knob.

  When the gear 56 of the drive member 50A rotates in the direction of the arrow AR2, the cam 3A having three peaks rotates in the direction of the arrow DR1, and similarly, the cam 4A having three peaks rotates in the direction of the arrow DR2. The cams 3 </ b> A and 4 </ b> A are configured such that the lower point (bottom dead center) of the cam 4 </ b> A contacts the protrusion 25 when the apex (top dead center) of the cam 3 </ b> A contacts the protrusion 15. .

  At the time shown in FIG. 10, the protrusion 15 is in sliding contact with the circumferential surface of the cam 3A so as to go from the apex of the cam 3A to the lower point, while the cam 4A starts from the lower point of the cam 4A. The projecting portion 25 is in sliding contact with the peripheral surface of the cam 4A so as to be directed to the apex.

  For the cam 3A, the direction of the force in the rotational direction that the cam 3A receives from the protrusion 15 is the direction indicated by the arrow DR3. The arrow DR3 direction is the same as the direction in which the cam 3A rotates due to the rotational movement of the drive member 50A in the arrow AR2 direction, that is, the arrow DR1 direction. The force shown in the direction of the arrow DR3 is transmitted as the first torque to the driving member 50A through the gear 5, and acts in the same direction as the direction in which the driving member 50A moves.

  For the cam 4A, the direction of the force in the rotational direction that the cam 4A receives from the protrusion 25 is the direction indicated by the arrow DR4. The direction of the arrow DR4 is opposite to the direction in which the cam 4A is rotated by the rotational movement of the drive member 50A in the direction of the arrow AR2, that is, the direction of the arrow DR2. The force shown in the direction of the arrow DR4 is transmitted as the second torque to the driving member 50A through the gear 6, and acts in the direction opposite to the direction in which the driving member 50A moves.

  In the cams 3A and 4A, operations opposite to the above are performed at different timings. That is, when the drive member 50A rotates, the cams 3A and 4A rotate in synchronization (rotate while maintaining the cycle and phase). The first torque waveform and the second torque waveform received by the drive member 50A due to the rotation of the cams 3A and 4A while the gear 56 of the drive member 50A rotates by a predetermined distance are opposite in phase and are displaced (torque). Are absolute to each other.

  The first torque received by the drive member 50A with the rotation of the cam 3A and the second torque received by the drive member 50A with the rotation of the cam 4A are in a mutually canceling relationship. Therefore, the maximum value of the torque acting on the driving member 50A as the combined force is sufficiently smaller (for example, 5% or less) than the maximum value of the torque received by the driving member 50A by the individual cams 3A, 4A. Since the peak-to-peak of the torque for driving the drive member 50A can be reduced, the power generation amount per input torque can be increased. In other words, when a plurality of piezoelectric elements are used, the power generation efficiency per piezoelectric element can be improved.

  Referring to FIG. 11, a model as shown in FIG. 11 is also obtained in the case of the second embodiment. That is, the follower mechanism 10 and the follower mechanism 20 are disposed so as to face each other with the drive member 50A (not shown) interposed therebetween. The follower mechanism 10 and the protrusion 15 can be regarded as being displaced by the cam curve 1S moving in the direction of the arrow A1, and the follower mechanism 20 and the protrusion 25 are displaced by the cam curve 2S moving in the direction of the arrow A2. Can be considered to be. The arrow A1 direction and the arrow A2 direction are opposite to each other.

  Assuming that the pressure angle of the protrusion 15 with respect to the cam curve 1S is ψ, of the force F1 that the protrusion 15 receives from the cam 3 (cam curve 1S), the force F1y used for displacement of the protrusion 15 (piezoelectric element 11) and the like Becomes F1 cos ψ. Similarly, when the pressure angle of the protrusion 25 with respect to the cam curve 2S is ψ, the protrusion 25 is subjected to displacement of the protrusion 25 (piezoelectric element 21) and the like out of the force F2 that the protrusion 25 receives from the cam 4 (cam curve 2S). The force F2y is F2cosψ. Here, the friction generated between the cam curves 1S and 2S and the protrusions 15 and 25 can be ignored by providing sufficient lubricating means between them. Based on the above model, it is possible to apply the ideas of the equations (1) to (3) described in the case of the first embodiment to the present embodiment.

[Second configuration example of cam curve]
With reference to FIG. 12, a second configuration example of the cam curves of the cams 3 and 4 that can be preferably implemented when the ideas of the first and second embodiments are employed will be described. When the cam curve of the second configuration example is employed, a torque curve having a sine wave shape for two cycles appears when the cam rotates 360 °. Specifically, let A be an arbitrary coefficient. Factor A is a value corresponding to the vibration amplitude of the displacement y r of the projections 15 and 25 of the follower mechanism 10 and 20. Next, with respect to the cams 3 and 4 provided in both the cam mechanism 1 and the cam mechanism 2, the number of cam peaks is n (n = 1, 2, 3, 4...), And the cam rotation direction. Let r be the position at and the average radius of the cam be R avg . These values are values common to the cams 3 and 4 (same values). The function f (r) is expressed by the following equation (4).

When the spring constants of both the follower mechanism 10 including the piezoelectric element 11 and the follower mechanism 20 including the piezoelectric element 21 are k, the position r in the rotation direction of the cam is expressed by the following equation (5). displacement y r is expressed upon.

  By using the above equations (4) and (5), the cam curve L2 of the cams 3 and 4 can be expressed by the following equation (6).

The above equations (4) to (6) are calculated based on the following concept. That is, it is assumed that the cam mechanism 1 (cam 3) and the follower mechanism 10 (protrusion 15) are modeled as in the case of the first configuration example (see FIG. 6). Here, the number n of the peaks of the cam 3 is 1, the minimum radius of the cam 3 is R min, and the maximum radius of the cam 3 is R min + y r (max) .

  Similarly to the case of the first configuration example described above, when the pressure angle of the protrusion 15 with respect to the cam curve 1S is ψ, the protrusion 15 (piezoelectric) of the force F1 that the protrusion 15 receives from the cam 3 (cam curve 1S). The force F1y used for displacement of the element 11) or the like is F1cosψ. Similarly, when the pressure angle of the protrusion 25 with respect to the cam curve 2S is ψ, the protrusion 25 is subjected to displacement of the protrusion 25 (piezoelectric element 21) and the like out of the force F2 that the protrusion 25 receives from the cam 4 (cam curve 2S). The force F2y is F2cosψ. Here, the friction generated between the cam curves 1S and 2S and the protrusions 15 and 25 can be ignored by providing sufficient lubricating means between them.

Based on the above, when calculating a cam curve having two sinusoidal waveforms between 360 °, such as the first torque and the second torque shown in FIG. ).
T = k · {tan ψ · y r · (R min + y r )} = A · {sin (2 · θ−π / 2) +2} (B)
As in the case of the first configuration example, the pressure angle is expressed by ψ = dy / dr. Therefore, in the above formula (B), the relationship θ = r / R avg is established. Here, it is assumed that the relationship of R avg = R min + y r (max) is established. Since yr is a function of r, the above equations (4) to (6) can be obtained by solving the above equation (B). When the above formulas (4) to (6) are applied to the idea of the first embodiment and an experiment by simulation is performed, it is found that the combined value of torque acting as a reaction force on the driving member can be sufficiently reduced. It was.

(Cam shape based on second configuration example of cam curve)
FIG. 13 is a plan view showing the shape of the cam 3B based on the second configuration example when the number of cam ridges is n = 1. FIG. 14 is a plan view showing the shape of the cam 3C based on the second configuration example when the number of cam ridges is n = 3. FIG. 15 is a plan view showing the shape of the cam 3D based on the second configuration example when the number of ridges of the cam is n = 5. Even when any of the configurations of these cams 3B, 3C, and 3D is adopted, the phases of the first torque and the second torque are opposite, and the absolute values of the displacements (torques) are the same. By doing so, the combined value of the torque acting as a reaction force on the drive member can be reduced.

In the case of employing a cam curve (FIG. 5) of the first configuration example above, at the timing of the rotational angle of the cam is 0 ° (360 °), the change of the displacement y r has a steep, slight sound There is a concern that this will occur. In the case of employing the second configuration example, the timing of the rotational angle of the cam is 0 ° (360 °) and 180 °, have become those changes in displacement y r is smoothly changed, sound or the unnecessary vibration There seems to be almost no occurrence.

[Third configuration example of cam curve]
With reference to FIG. 16, a third configuration example of the cam curves of the cams 3 and 4 that can be preferably implemented when the ideas of the first and second embodiments are employed will be described. When the cam curve of the third configuration example is employed, a torque curve having a triangular wave shape for one cycle appears when the cam rotates 360 °. Specifically, let A be an arbitrary coefficient. Factor A is a value corresponding to the vibration amplitude of the displacement y r of the projections 15 and 25 of the follower mechanism 10 and 20. Next, with respect to the cams 3 and 4 provided in both the cam mechanism 1 and the cam mechanism 2, the number of cam peaks is n (n = 1, 2, 3, 4...), And the cam rotation direction. Let r be the position at and the average radius of the cam be R avg . These values are values common to the cams 3 and 4 (same values). The function f (r) is expressed by the following equation (7).

When the spring constants of both the follower mechanism 10 including the piezoelectric element 11 and the follower mechanism 20 including the piezoelectric element 21 are k, the position r in the rotation direction of the cam is calculated by the following equation (8). displacement y r is expressed upon.

  By using the above equations (7) and (8), the cam curve L3 of the cams 3 and 4 can be expressed by the following equation (9).

[Fourth configuration example of cam curve]
With reference to FIG. 17, a description will be given of a fourth configuration example of the cam curves of the cams 3 and 4 that can be suitably implemented when the ideas of the first and second embodiments are employed. In the cam curve of the fourth configuration example, two different cycles C1 and C2 appear in one torque curve. Also in the fourth configuration example, the waveform of the first torque and the waveform of the second torque that act on the drive member while the drive member moves relative to each other by a predetermined distance have opposite phases, and the absolute value of the displacement (torque) Are identical to each other. With respect to these points, the fourth configuration example is the same as the first to third configuration examples described above.

Based on the same concept as the first to third configuration examples, the torque T is expressed by the following equation (C) in the cam curve of the fourth configuration example.
T = k · {tan ψ · y r · (R min + y r )} = A · f (θ) (C)
The first torque is represented by a predetermined function f1 (θ), and the second torque is represented by a predetermined function f2 (θ).

[Contrast between measured torque and calculated torque]
With reference to FIG. 18, the result of verifying the validity of the formula specified in each of the above configuration examples will be described. Here, the result verified based on said 2nd structural example is demonstrated as a representative example. Setting conditions, number of peaks of the cam is n = 1, the coefficient for the vibration amplitude of the displacement y r is A = 0.016, the minimum radius of the cam is R min = 6.5 mm, the spring constant k = 3.2 N / mm, the minimum change amount (unit change amount) of the position in the rotational direction of the cam is dr = 0.238 mm, and the maximum displacement of the cam is yr (max) = 0.65 mm.

  When the above conditions were applied to the expression of the second configuration example, the maximum torque T was 0.223 mN · m (maximum value of calculated torque). The maximum value of the torque acting on the drive member 50 as a composite torque is 3.3% or less compared to the maximum value of the torque received by the drive member 50 by the individual cams 3 and 4, and can be sufficiently reduced. It was. On the other hand, when the actually measured torque was measured, the maximum value was 0.006 mN · m larger than the maximum value of the calculated torque. The difference was 2.9% as a percentage. Therefore, the formula specified in the second configuration example is considered to have sufficient validity.

  Although the embodiment has been described above, the above disclosure is illustrative in all respects and is not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 2 cam mechanism, 1S, 2S, L1, L2, L3 cam curve, 3, 3A, 3B, 3C, 3D, 4, 4A cam, 5, 6, 56 gear, 10, 20 follower mechanism, 11 piezoelectric element , 11A, 11B surface, 12, 22 support body, 13 stopper, 13A, 14B, 14D contact part, 14 lever, 14A connection part, 14C displacement part, 15, 25 protrusion part, 16 rotating shaft, 21 piezoelectric element (compression) Member) 50, 50A drive member, 51, 52 rack teeth, 55 central axis, 100, 100A energy conversion system.

Claims (5)

  1. An energy conversion system for generating electricity by applying a load to a piezoelectric element,
    A first cam mechanism and a second cam mechanism;
    A first follower mechanism that includes a piezoelectric element that receives a load due to rotation of the first cam mechanism, and that imparts a reaction force to the first cam mechanism as the piezoelectric element receives the load;
    A second follower mechanism that includes a compression member that receives a load by rotation of the second cam mechanism, and that imparts a reaction force to the second cam mechanism as the compression member receives the load;
    A drive member that rotates the first cam mechanism and the second cam mechanism by moving relative to the first cam mechanism and the second cam mechanism;
    When the driving member rotates the first cam mechanism and the second cam mechanism, the driving member receives a first torque received from the first follower mechanism through the first cam mechanism, and the second follower. The second torque received from the mechanism through the second cam mechanism acts at the same period,
    The waveform of the first torque and the waveform of the second torque that act on the drive member while the drive member moves relative to each other by a predetermined distance have opposite phases and the same absolute value of displacement.
    Energy conversion system.
  2. The compression member is a piezoelectric element.
    The energy conversion system according to claim 1.
  3. Let A be an arbitrary coefficient,
    About cams provided in both the first cam mechanism and the second cam mechanism,
    The number of peak portions of the cam is n (n = 1, 2, 3, 4...)
    The position in the rotational direction of the cam is r,
    When the average radius of the cam is R avg ,
    The function f (r) is expressed by the following equation (1):

    When the spring constants of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member are k,
    By the following equation (2), the displacement y r in the rotation angle r of the cam are represented,

    The cam curve L1 of the cam is expressed by the following equation (3):

    The energy conversion system according to claim 1 or 2.
  4. Let A be an arbitrary coefficient,
    About cams provided in both the first cam mechanism and the second cam mechanism,
    The number of peak portions of the cam is n (n = 1, 2, 3, 4...)
    The position in the rotational direction of the cam is r,
    When the average radius of the cam is R avg ,
    The function f (r) is expressed by the following equation (4):

    When the spring constants of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member are k,
    By the following equation (5), the displacement y r in the rotation angle r of the cam are represented,

    The cam curve L2 of the cam is expressed by the following equation (6).

    The energy conversion system according to claim 1 or 2.
  5. Let A be an arbitrary coefficient,
    About cams provided in both the first cam mechanism and the second cam mechanism,
    The number of peak portions of the cam is n (n = 1, 2, 3, 4...)
    The position in the rotational direction of the cam is r,
    When the average radius of the cam is R avg ,
    The function f (r) is expressed by the following equation (7):

    When the spring constants of both the first follower mechanism including the piezoelectric element and the second follower mechanism including the compression member are k,
    By the following equation (8), the displacement y r in the rotation angle r of the cam are represented,

    The cam curve L3 of the cam is expressed by the following equation (9).

    The energy conversion system according to claim 1 or 2.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6230143B1 (en) * 2017-08-17 2017-11-15 次郎 蔭山 Battery-free electronic watches and electronic equipment.

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4843893Y1 (en) * 1967-05-31 1973-12-18
JPS5761856A (en) * 1980-10-01 1982-04-14 Nec Corp Cam mechanism
JPH0220627A (en) * 1988-07-05 1990-01-24 Ishikawajima Harima Heavy Ind Co Ltd Method and apparatus for cancelling torque in drive of transfer apparatus
JPH09269041A (en) * 1996-04-01 1997-10-14 Sankyo Seisakusho:Kk Motion transducing device
JP2003148592A (en) * 2001-11-15 2003-05-21 Matsushita Electric Works Ltd Cam device
US20050269907A1 (en) * 2004-06-08 2005-12-08 Erickson David J Power generator employing piezoelectric materials

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4843893Y1 (en) * 1967-05-31 1973-12-18
JPS5761856A (en) * 1980-10-01 1982-04-14 Nec Corp Cam mechanism
JPH0220627A (en) * 1988-07-05 1990-01-24 Ishikawajima Harima Heavy Ind Co Ltd Method and apparatus for cancelling torque in drive of transfer apparatus
JPH09269041A (en) * 1996-04-01 1997-10-14 Sankyo Seisakusho:Kk Motion transducing device
JP2003148592A (en) * 2001-11-15 2003-05-21 Matsushita Electric Works Ltd Cam device
US20050269907A1 (en) * 2004-06-08 2005-12-08 Erickson David J Power generator employing piezoelectric materials

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6230143B1 (en) * 2017-08-17 2017-11-15 次郎 蔭山 Battery-free electronic watches and electronic equipment.

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