Balanced spring type piezoelectric resonator, especially for rotary motors for timepieces

Abstract

To provide a piezoelectric resonator capable of withstanding a high electromagnetic field while maintaining low power consumption and volume.SOLUTION: The present invention relates to a piezoelectric resonator 1 for a rotary piezoelectric motor. The resonator comprises a fixed base 3, and an oscillating weight 2 extending around a longitudinal axis. The oscillating weight has an inertial block 4, preferably two opposite inertial blocks. The piezoelectric resonator comprises a flexible blade guide connecting the oscillating weight to the base, and can oscillate the oscillating weight around a rotation center in a pendulum motion manner. The flexible blade guide comprises: a first flexible blade 6 connected to the base and / or the oscillating weight, and allows the oscillating weight to be displaced relative to the base; and a helical spring 5 connected to the base and / or the oscillating weight. The helical spring comprises, at least in part, an electrically actuatable piezoelectric material, which deforms the helical spring and causes the oscillating weight to oscillate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of piezoelectric resonators, in particular for rotary piezoelectric motors, and further to the technical field of timepieces equipped with such rotary piezoelectric motors. [Background technology]

[0002] The electric motors usually used in the manufacture of portable timepieces (e.g. wristwatches, pocket watches) are rotary motors of the "Lavet" type, which operate on electro-magnetic physical principles. This type of motor generally comprises a stator with a coil and a magnetized rotor that rotates due to the phase-shift actuation of the coil.

[0003] However, such motors have a limited ability to withstand high magnetic fields: above a certain magnetic field value, the motor will stall. Typically, a magnetic field greater than 2 mT will cause the motor to stall.

[0004] Therefore, to avoid this problem, it is necessary to design motors that operate on other physical principles.

[0005] For example, there are motors that use electrostatic combs, such as those described in Swiss Patent CH 709512. However, the combs take up space and consume more energy than "Lavet" type motors.

[0006] Motors based on the piezoelectric effect have also been developed, for example in European Patent EP 0 587 031. However, these are limited to actuating the date and are unable to drive the seconds hand, which usually requires the most energy, due to their high power consumption and the risk of premature wear. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a piezoelectric resonator, particularly for rotary piezoelectric motors, that can withstand high electromagnetic fields while maintaining low power consumption and volume. [Means for solving the problem]

[0008] To this end, the invention relates to a piezoelectric resonator, in particular for a rotary piezoelectric motor, comprising a fixed base and a seismic mass extending around a longitudinal axis, said seismic mass having at least one inertial block, preferably two opposite inertial blocks.

[0009] The invention is innovative in that the piezoelectric resonator comprises a flexible blade guide connecting the oscillating mass to the base, thereby causing the oscillating mass to oscillate around a center of rotation in a pendulum motion, the flexible blade guide comprising at least one first flexible blade connected to the base and / or the oscillating mass, thereby allowing the oscillating mass to be displaced relative to the base, and the flexible blade guide comprising a helical spring connected to the base and / or the oscillating mass, the helical spring comprising, at least in part, an electrically actuable piezoelectric material, thereby deforming the helical spring and causing the oscillating mass to oscillate.

[0010] A resonator with such a configuration can provide efficient motion. In fact, by actuating the piezoelectric material of the helical spring, the helical spring contracts and expands, and the oscillating mass vibrates by rotating around the center of rotation thanks to the flexible blade of the flexible guide. In this way, since only a small amount of energy is required to actuate the flexible blade, the resonator causes the oscillating mass to vibrate with almost no energy consumption.

[0011] Thus, depending on the field of application of the piezoelectric resonator, it is possible to transmit a vibratory movement to other mechanical parts, for example to the gears of a motor.

[0012] In certain embodiments of the invention, the flexible guide comprises a second flexible blade connecting the seismic mass to the base, and the first flexible blade connecting the base to the seismic mass.

[0013] In certain embodiments of the invention, the first flexible blade and the second flexible blade do not intersect and extend from a central portion of the oscillating weight to an eccentric portion of the base.

[0014] In certain embodiments of the present invention, the first flexible blade and the second flexible blade are configured to form an angle in the range of 30° to 150°, preferably in the range of 60° to 130°, and more preferably in the range of 90° to 120°.

[0015] In certain embodiments of the invention, the helical spring is connected to the oscillating weight, thereby actuating the oscillation.

[0016] In a particular embodiment of the invention, the flexible guide has two RCC type flexible pivots, the flexible guide comprising an intermediate movable element, a first pair of flexible blades including the first flexible blade and a second flexible blade connecting the base to the intermediate movable element, and a second pair of flexible blades connecting the intermediate movable element to the vibration mass.

[0017] In certain embodiments of the invention, the first flexible blade and the second flexible blade do not intersect but move away from each other as they move from the intermediate movable element to the base.

[0018] In certain embodiments of the present invention, the first flexible blade and the second flexible blade form an angle in the range of 30° to 100°, preferably in the range of 40° to 80°.

[0019] In certain embodiments of the present invention, the first flexible blade and the second flexible blade are configured axially symmetrical to each other.

[0020] In certain embodiments of the invention, the helical spring is connected to the intermediate element and the base, and the helical spring causes the intermediate movable element to oscillate when actuated.

[0021] In certain embodiments of the invention, the helical spring is disposed between the first pair of flexible blades and the second pair of flexible blades.

[0022] In certain embodiments of the invention, the helical spring and the first pair of flexible blades form an angle in the range of 60° to 120°, preferably in the range of 80° to 100°.

[0023] In certain embodiments of the invention, the helical spring and the second pair of flexible blades form an angle in the range of 20° to 60°, preferably in the range of 30° to 45°.

[0024] In a particular embodiment of the invention, the flexible guide has two RCC type flexible pivots, the flexible guide comprises an intermediate movable element and a pair of flexible blades with the first flexible blade, the pair of flexible blades connecting the intermediate movable element to the oscillating mass, the helical spring connects the base to the intermediate movable element, the flexible guide comprises a second helical spring connecting the base to the intermediate movable element, the second helical spring comprises an electrically actuable piezoelectric material, thereby deforming the second helical spring and causing the oscillating mass to oscillate.

[0025] In certain embodiments of the present invention, the first and second helical springs are configured to form an angle in the range of 80° to 160°, preferably in the range of 100° to 140°, and more preferably in the range of 110° to 130°.

[0026] In a particular embodiment of the present invention, the first helical spring and the second helical spring are configured axially symmetrical to each other.

[0027] In certain embodiments of the present invention, the piezoelectric resonators are arranged substantially in the same plane.

[0028] In certain embodiments of the invention, the piezoelectric resonator is configured to vibrate the seismic mass at a natural frequency of the resonator.

[0029] In a particular embodiment of the invention, the piezoelectric resonator preferably comprises, for the most part, a monocrystalline or polycrystalline material construction, such as silicon, glass, ceramics, metal, which has low electrical conductivity, is obtained by, for example, a photolithographic micromachining process of the MEMS type, and is non-magnetic.

[0030] In a particular embodiment of the invention, the flexible guide is made in one piece.

[0031] The invention further relates to a piezoelectric motor, in particular for a display device of a timepiece, comprising such a piezoelectric resonator.

[0032] In a particular embodiment of the invention, the piezoelectric motor comprises at least one claw, preferably two claws, and a movable wheel, the claws being attached to the oscillating mass of the piezoelectric resonator, thereby rotating the movable wheel in a first direction when the oscillating mass vibrates.

[0033] The invention further relates to a timepiece comprising a gear transmission configured to rotate at least one hand, and a timepiece movement comprising a piezoelectric motor as described above configured to actuate the gear transmission.

[0034] Other features and advantages will become apparent on reading the following description, given by way of illustration and not of limitation, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a schematic perspective view from above of a first embodiment of a piezoelectric resonator according to the invention, in particular for a rotary motor; [Figure 2] 1 is a schematic perspective view from above of a second embodiment of a piezoelectric resonator according to the invention, in particular for a rotary motor; [Figure 3] 3 shows a schematic view from above of a third embodiment of a piezoelectric resonator according to the invention, in particular for a rotary motor; FIG. [Figure 4] FIG. 1 is a schematic perspective view of a rotary piezoelectric motor including the resonator as seen from above. DETAILED DESCRIPTION OF THE INVENTION

[0036] 1 to 3 show different embodiments of piezoelectric resonators 1, 10, 20, which are used in particular in rotary motors. In particular, the motors can be used in timepieces to actuate display devices including hands arranged on a dial. The piezoelectric resonators 1, 10, 20 preferably extend substantially in one plane.

[0037] In FIG. 1, a piezoelectric resonator 1 according to a first embodiment has a base 3, here of substantially triangular shape.

[0038] The resonator 1 also comprises a seismic mass 2, here M-shaped, with a V-shaped main arm at either end of which are arranged two inertial blocks 4, which extend towards opposite sides of the base 13 and are here substantially straight.

[0039] The base 3 is disposed on top of the M. The vibration mass 2 and the base 3 are preferably disposed in the same plane.

[0040] The resonator comprises a flexible blade guide connecting the oscillating mass 2 to a base 3, which allows the oscillating mass 2 to oscillate in a pendulum motion about a centre of rotation which is located substantially in the centre of the oscillating mass 2, i.e. in the centre of the arm, preferably in the centre of gravity of the oscillating mass 2.

[0041] The flexible guide has two flexible blades: a first flexible blade 6 and a second flexible blade 7, which are connected to the same central part of the oscillating mass 2, here at the inner apex of the M, forming a pivot of the RCC (Remote Center Compliance) type.

[0042] The first flexible blade 6 and the second flexible blade 7 are connected to two eccentric portions on opposite sides of the base 3, in this case the corners of a rectangle.

[0043] The first flexible blade 6 and the second flexible blade 7 do not intersect with each other and extend from the inside of the vibration weight 2 to the base 3 .

[0044] The first flexible blade 6 and the second flexible blade 7 are configured to form a non-zero angle between them, which is in the range of 30° to 150°, preferably in the range of 60° to 130°, and more preferably in the range of 90° to 120°.

[0045] According to the invention, the flexible blade guide further comprises a helical spring 5 connected to the oscillating weight 2. This helical spring 5 is arranged on the opposite side of the M from the base 3.

[0046] The helical spring 5 has several elastic coils. The helical spring 5 has an inner end connected to the fixed Bromstad and an outer end followed by a substantially straight section connected to the intermediate movable element 8.

[0047] The helical spring 5 comprises, at least in part, an electrically actuatable piezoelectric material that deforms the helical spring 5 and causes the oscillating weight 2 to vibrate. The piezoelectric material is preferably disposed along the entire length of the helical spring 5. The helical spring 5 may, for example, include a layer of piezoelectric material sandwiched between two electrode layers.

[0048] These electrode layers are disposed on a unitary structural support material, such as single or polycrystalline silicon, quartz, glass, metal, or the like.

[0049] To actuate the blade on which the coil resides, the fixed Bromstad 9 has electrical contacts connected to the electrode layer to receive a voltage and actuate the piezoelectric layer of the helical spring 5 .

[0050] This piezoelectric layer preferably comprises a crystalline or polycrystalline material, for example a solid ceramic (in the case of sodium potassium niobate) or a PZT type ceramic (in the case of lead titanium zirconate).

[0051] This activation is caused by an alternating voltage. By electrically activating the layer of piezoelectric material, the helical spring 5 alternately contracts and expands around its center, causing a rotational displacement of the oscillating mass 2 via the intermediate element 8. This vibration occurs at a specific frequency, preferably at the resonant frequency of the resonator.

[0052] The piezoelectric layer disposed over the entire surface of the helical spring 5 significantly increases the efficiency of the actuator compared to a simple flexible straight blade occupying the same space.

[0053] The oscillating mass 2 performs a pendulum movement about a center of rotation, guided in its movement by two flexible blades 6, 7 of a flexible guide forming a pivot of the RCC type. The oscillating mass 2 therefore oscillates and the two inertial blocks 4 are laterally displaced at a specific frequency, preferably the natural frequency of the resonator 1. The oscillating mass 2 oscillates about a center of rotation located in the center of the intermediate movable element 8.

[0054] In the second embodiment of FIG. 2, the piezoelectric resonator 10 has a base 13, which here has two curved portions 21, 22 arranged on either side of a substantially triangular central portion 23 and extending to the seismic mass 12.

[0055] The resonator 10 also comprises a seismic mass 12. The seismic mass 12 has a main arm at each end of which two inertial blocks 14 are arranged, which extend on either side of a base 13. The arms are arranged tangentially to the vertices of a triangle. The arms are substantially curved in the central region to provide space for, for example, the rotor of a motor. The seismic mass 12 and the base 13 are preferably arranged in the same plane.

[0056] The resonator comprises a flexible blade guide connecting the oscillating mass 12 to a base 13, which allows the oscillating mass 12 to oscillate about a centre of rotation in a pendulum motion.

[0057] The flexible guide has a first RCC type pivot including an intermediate moving element 8, a first pair of flexible blades 16, 17 connecting the base to the intermediate moving element 8, and a second pair of flexible blades connecting the intermediate moving element to the oscillating mass 12 and forming a second RCC type pivot.

[0058] The intermediate movable element 8 is a point element and is smaller in size than the base 8 and the vibration weight 12. The point element 8 has, for example, a cylindrical shape. Preferably, the center of rotation is located substantially at the center of the intermediate movable element 8.

[0059] The first pair of flexible blades includes a first flexible blade 16 and a second flexible blade 17 that connect the base 13 to the intermediate movable element 8. Preferably, the first flexible blade 16 and the second flexible blade 17 are substantially straight.

[0060] The first flexible blade 16 and the second flexible blade 17 do not intersect and move away from each other as they move from the intermediate movable element 8 towards the same first curved portion 21 of the base 13 .

[0061] The first flexible blade 16 and the second flexible blade 17 form an angle within a range of 30° to 100°, preferably within a range of 40° to 80°.

[0062] The second pair of flexible blades includes a third flexible blade 18 and a fourth flexible blade 19 that extend from the intermediate movable element 8 to the oscillating weight 2, more specifically to the top of the inertia block 14 below the arm. The second pair of flexible blades forms a second RCC type pivot.

[0063] Thus, the flexible blades 16, 17 of the first pair of flexible blades extend on opposite sides from the flexible blades 18, 19 of the second pair of flexible blades.

[0064] The third flexible blade 18 and the fourth flexible blade 19 are configured to form an angle within a range of 30° to 150°, preferably within a range of 60° to 130°, and more preferably within a range of 90° to 120°.

[0065] According to the invention, the flexible guide further comprises a helical spring 15 made of piezoelectric material, which is substantially identical to the helical spring 5 according to the first embodiment of FIG.

[0066] The helical spring 15 is disposed between the base 13 and the intermediate movable element 8, in particular at the second curved portion 22 of the base 13. The helical spring 15 is further connected to each of the flexible blades by a straight section 33 connected to the intermediate movable element 8, and further connected at its inner end to the base 13.

[0067] The helical spring 15 and the first pair of flexible blades 16, 17, in particular the second flexible blade 17, form an angle in the range of 60° to 120°, preferably in the range of 80° to 100°. The helical spring 5 and the second pair of flexible blades 18, 19, in particular the fourth flexible blade 19, form an angle in the range of 20° to 60°, preferably in the range of 30° to 45°.

[0068] In this embodiment, the helical spring 15, when activated, acts on the intermediate movable element 8 causing it to oscillate. The movement of the intermediate movable element 8 is guided by a first pair of flexible blades 16, 17.

[0069] The vibrations of the intermediate movable element 8 are transmitted to the oscillating mass 12 thanks to a second pair of flexible blades 18,19.

[0070] The oscillating mass 12 thus oscillates about a center of rotation, here configured at the center of the intermediate element 8. The two inertial blocks 14 move laterally at a specific frequency, preferably at the natural frequency of the resonator 10.

[0071] The RCC type double pivot makes it possible to increase the amplitude of vibration of the oscillating mass 12 thanks to the second pair of flexible blades 18, 19.

[0072] The piezoelectric resonator 20 according to the third embodiment of FIG. 3 has a base 13, which here has two curved portions 21, 22 arranged on either side of a substantially triangular central portion 23 and extending to the seismic mass 12.

[0073] The piezoelectric resonator 20 has a oscillating mass 12 with a main arm at either end of which are arranged two inertia blocks 14 that extend on either side of a base 13. The arms are arranged tangentially to the apexes of a triangle. The arms are substantially curved in the central region, thereby approaching the main apex of the triangle. The oscillating mass 12 and the base 13 are preferably arranged in the same plane.

[0074] The piezoelectric resonator 20 includes flexible blade guides 16, 17 connecting the oscillating mass 12 to the base 13, which allows the oscillating mass 12 to oscillate about its center of rotation in a pendulum-like manner.

[0075] The flexible guide has two RCC type pivots. Such a flexible guide generally comprises an intermediate moving element 8, a first pair of flexible blades 26, 27 connecting the intermediate moving element 8 to the oscillating mass 2, and a second pair of flexible blades connecting the base 13 to the intermediate moving element 8.

[0076] In this embodiment, the second pair of flexible blades of the second RCC-type pivot are replaced by helical springs.

[0077] The intermediate movable element 8 is a point element, and is smaller in size than the base 8 and the vibration weight 2. The point element 8 has, for example, a cylindrical shape. Preferably, the center of rotation is located at the center of the intermediate movable element 8.

[0078] The first pair of flexible blades includes a first flexible blade 26 connecting the intermediate movable element 8 to the base 13 and a second flexible blade 27 connecting the base 13 to the intermediate movable element 8 .

[0079] The flexible guide comprises a first helical spring 5 and a second helical spring 25. Each helical spring 5, 25 is arranged between the base 3 and the intermediate movable element 8, in particular in each curved portion 21, 22 of the base 3.

[0080] The intermediate movable element 8 is further connected to each of the flexible blades by a straight section, with the inner end of each helical spring being connected to the base 3. Thus, the first helical spring 5 and the second helical spring 25 extend on the opposite side of the first pair of flexible blades from the flexible blades 26, 27.

[0081] The first flexible blade 24 and the second flexible blade 25 are configured to form an angle within a range of 80° to 160°, preferably within a range of 100° to 140°, and more preferably within a range of 110° to 130°. The first spiral spring 24 and the second spiral spring 25 are configured to be axially symmetrical to each other.

[0082] The first helical spring 24 and the second helical spring 25 are substantially identical to the helical springs according to the first and second embodiments, and both helical springs 24, 25 also comprise a piezoelectric material.

[0083] In this embodiment, the two helical springs 5, 25 are actuated, preferably alternately, so that they act on the intermediate movable element 8 and cause it to oscillate. The rotational movement of the intermediate movable element 8 is therefore guided by the helical springs 24, 25, similar to an RCC-type pivot with straight blades.

[0084] The vibrations of the intermediate movable element 8 are transmitted to the oscillating mass 12 thanks to a second pair of flexible blades 26 , 27 .

[0085] In this way, the oscillating mass 2 oscillates about a centre of rotation corresponding to the intersection of the two flexible blades in each pair, in this case the intermediate element 8. The two inertial blocks 14 are displaced laterally at a specific frequency.

[0086] The RCC type pivot increases the amplitude of vibration of the oscillating mass 2 thanks to the second pair of flexible blades 9,11.

[0087] The resonators 1, 10, 20 according to the embodiments described above preferably comprise in large part monocrystalline or polycrystalline materials such as silicon, glass, ceramics, metals.

[0088] The resonators 1, 10, 20 are obtained, for example, by a photolithographic micromachining process of the MEMS (Micro-Electro-Mechanical Systems) type, the rigidity, elasticity and machining precision of such materials giving the resonators 1, 10, 20 a high resonance performance.

[0089] Additionally, the non-magnetic and low electrical conductivity properties of some of these materials provide excellent resistance to large DC and AC magnetic fields.

[0090] The resonators 1, 10, 20 are configured to vibrate the oscillating masses 2, 12 at the natural frequency of the resonators 1, 10, 20. In this way, the energy consumption of the resonators can be reduced, especially by increasing the angular travel of the oscillating masses.

[0091] 4 shows one embodiment of a rotary piezoelectric motor 30, particularly for a timepiece display device. The piezoelectric motor 30 can be used in particular to actuate a display device, such as a hand on a dial, in a timepiece. The piezoelectric motor 30 is configured to rotate and actuate a mechanical gear transmission of the display device.

[0092] The piezoelectric motor 30 comprises a piezoelectric resonator according to the invention, in this case a piezoelectric resonator 10 according to the second embodiment shown in Figure 2. Piezoelectric resonators according to other embodiments can also be used without changing the operation of the piezoelectric motor 10. The piezoelectric resonator 10 is, for example, mounted by its base 13 to a plate.

[0093] The piezoelectric motor 10 further comprises a movable gear 51 and two pawls 52, 53 configured to rotate the movable gear 51 in one direction. The movable gear 51 preferably has peripheral teeth, preferably asymmetrical teeth, which determine the direction of rotation. The movable gear 51 is connected to a gear train to which the hands of a display device are attached.

[0094] The first claw 52 has the function of rotating the movable wheel 51 in a first direction, for example counterclockwise, and the second claw 53 holds the movable wheel 51 as the first claw 52 rewinds onto the next tooth of the rotor 51.

[0095] Each pawl 52, 53 has a flexible arm 54 with teeth 55 at the end thereof, preferably asymmetrical teeth.

[0096] The movable wheel 51 rotates thanks to the displacement of the first pawl 52, which is attached to the oscillating mass 12 of the piezoelectric resonator 10. Therefore, when the resonator vibrates, the first pawl 52 also vibrates, which causes the first pawl 52 to push or pull the movable wheel 51 in a first direction, depending on the position of the piezoelectric resonator relative to the movable wheel 51.

[0097] The second pawl 53 is assembled to the plate, plate bridge, or directly to the base 30, thereby reducing positioning errors caused by a series of assembly tolerances. The second pawl 53 has the function of preventing the gear from rotating in the direction opposite to the first direction. The teeth 55 of the second pawl 53, in conjunction with the asymmetric teeth, are configured to rotate the movable wheel 51 in the first direction and prevent the movable wheel 51 from rotating in the opposite direction.

[0098] For this reason, the flexible arms 54 of the pawls 52, 53 are in a relaxed, straight position when the teeth 55 are engaged with the tooth row of the movable wheel 51, and are curled up and bent when they are pushed outward by the tooth row when the movable wheel 51 is rotating in a first direction.

[0099] In the case of a watch, the resonant or natural frequency of the motor 1 is adapted to match the frequency of the quartz crystal used to set the movement's rate. An excitation frequency is selected that corresponds to a submultiple of the quartz crystal's frequency, which is usually 32764 Hz. For example, a frequency of 128 Hz or 256 Hz is selected. The frequency of the motor 1 is preferably adjusted and tuned to the excitation frequency so that its vibration amplitude does not fall below 90-95% of its maximum amplitude.

[0100] Optionally, the second pawl 53 can be configured to be used as a pitch sensor to determine the rotation distance or rotation speed of the movable wheel 51. For this purpose, the flexible arm 54 of the second pawl 53 is provided with a piezoelectric material that is connected to a counting unit. In this way, each time the second pawl 53 is bent, the counting unit registers a rotation of the movable wheel 51 by one tooth.

[0101] It will be understood that various modifications and / or improvements and / or combinations apparent to those skilled in the art may be made to the various embodiments of the invention described above without departing from the scope of the invention as defined by the appended claims.

Claims

1. A piezoelectric resonator (1, 10, 20), in particular for a rotary piezoelectric motor, comprising: The piezoelectric resonator (1, 10, 20) comprises a rectangular fixed base (3, 13) and a V-shaped vibration weight (2, 12) extending along the longitudinal direction of the base and spaced apart at a center portion of the base from an end portion of the base in the longitudinal direction; The vibration mass (2, 12) has at least one inertial block (4, 14), the piezoelectric resonator comprises a flexible blade guide connecting the oscillating mass (2, 12) to the base (3, 13), which allows the oscillating mass (2, 12) to oscillate about a center of rotation in a pendulum motion; the flexible blade guide comprises a first flexible blade (6, 16, 26) and a second flexible blade (7) connected to the base (3, 13) and / or the vibration mass (2, 12), thereby allowing the vibration mass (2, 12) to be displaced relative to the base (3, 13); the flexible blade guide comprises a helical spring (5, 15, 24) connected to the base (3, 13) and / or the oscillating weight (2, 12); the helical spring (5, 15, 24) comprises, at least in part, a piezoelectric material that can be electrically actuated to deform the helical spring (5, 15, 24) and cause the oscillating mass (2, 12) to oscillate; The flexible blade guide includes a second flexible blade (7) connecting the vibration weight (2) to the base (3). A piezoelectric resonator characterized by:

2. The second flexible blade (7) connects the vibration mass (2) to the base (3), The first flexible blade (6) connects the base (3) to the vibration mass (2).

2. The piezoelectric resonator according to claim 1.

3. The first flexible blade (6, 16) and the second flexible blade (7) do not intersect and move away from each other as they move from the central portion of the vibration weight (2) to the eccentric portion of the base (13).

2. The piezoelectric resonator according to claim 1.

4. The first flexible blade (6) and the second flexible blade (7) are configured to form an angle within the range of 30° to 150°.

2. The piezoelectric resonator according to claim 1.

5. The first flexible blade (6) and the second flexible blade (7) are configured axially symmetrical to each other.

3. The piezoelectric resonator according to claim 2.

6. The helical spring (5) is connected to the vibration mass (2) and thereby actuates the vibration.

2. The piezoelectric resonator according to claim 1.

7. The flexible blade guide has two RCC (Remote Center Compliance) type flexible pivots, The flexible blade guide comprises an intermediate movable element (8), a first pair of flexible blades (16, 17) including the first flexible blade (16) and the second flexible blade (17) connecting the base (13) to the intermediate movable element (8), and a second pair of flexible blades (18, 19) connecting the intermediate movable element (8) to the vibration weight (12).

2. The piezoelectric resonator according to claim 1.

8. The first flexible blade (6) and the second flexible blade (7) do not intersect and move away from each other as they move from the intermediate movable element (8) to the base (13).

8. The piezoelectric resonator according to claim 7.

9. The first flexible blade (16) and the second flexible blade (17) form an angle in the range of 30° to 100°.

8. The piezoelectric resonator according to claim 7.

10. The first flexible blade (16) and the second flexible blade (17) are configured axially symmetrically to each other.

6. The piezoelectric resonator according to claim 5.

11. The helical spring (5) is connected to the intermediate movable element (8) and the base (13); The helical spring (5) causes the intermediate movable element (8) to oscillate when actuated.

8. The piezoelectric resonator according to claim 7.

12. The helical spring (5) is disposed between the first pair of flexible blades (16, 17) and the second pair of flexible blades (18, 19).

12. The piezoelectric resonator according to claim 11.

13. The helical spring (5) and the first pair of flexible blades (16, 17) are configured to form an angle within the range of 60° to 120°.

12. The piezoelectric resonator according to claim 11.

14. The helical spring (5) and the second pair of flexible blades (18, 19) are configured to form an angle within the range of 20° to 60°.

12. The piezoelectric resonator according to claim 11.

15. The flexible blade guide has two RCC (Remote Center Compliance) type flexible pivots, The flexible blade guide comprises an intermediate movable element (8) and a pair of flexible blades (26, 27) including the first flexible blade (26) and the second flexible blade (27), The pair of flexible blades (26, 27) connect the intermediate movable element (8) to the oscillating weight (12), the helical spring (24) is a first helical spring, which connects the base (23) to the intermediate movable element (8); the flexible blade guide comprises a second helical spring (25) connecting the base (23) to the intermediate movable element (8); The second helical spring (25) has a piezoelectric material that can be electrically actuated to deform the second helical spring (25) and cause the oscillating weight (12) to vibrate.

2. The piezoelectric resonator according to claim 1.

16. The first helical spring (5) and the second helical spring (25) are configured to form an angle within the range of 80° to 160°.

16. The piezoelectric resonator according to claim 15.

17. The first spiral spring (5) and the second spiral spring (25) are configured axially symmetrically to each other.

16. The piezoelectric resonator according to claim 15.

18. be arranged substantially in the same plane 2. The piezoelectric resonator according to claim 1.

19. The vibration weight (2, 12) is configured to vibrate at the natural frequency of the piezoelectric resonator (1, 10, 20).

2. The piezoelectric resonator according to claim 1.

20. A piezoelectric motor for a display device of a timepiece, comprising: Equipped with a piezoelectric resonator (1, 10, 20) according to claim 1 A piezoelectric motor characterized by:

21. At least one claw (52) and a movable wheel (51), The claw (52) is attached to the vibration mass (32) of the piezoelectric resonator (1), thereby rotating the movable wheel (51) in a first direction when the vibration mass (32) vibrates.

21. The piezoelectric motor of claim 20.

22. 1. A timepiece comprising a timepiece movement comprising a gear transmission configured to rotate at least one hand, The timepiece comprises a piezoelectric resonator (1, 10, 20, 30, 40) according to claim 1 or a piezoelectric motor (30) according to claim 21 adapted to actuate the gear transmission. A timepiece characterized by:

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