A piezoelectric resonator with a flexible guide, particularly for a rotary motor for a timepiece

Abstract

To provide a piezoelectric resonator that can withstand high electromagnetic fields while maintaining small power consumption and volume.SOLUTION: There is provided a piezoelectric resonator (1), in particular for a rotary piezoelectric motor, the resonator (1) including a stationary base (3) and an oscillating mass (2) extending around a longitudinal axis, the oscillating mass (2) being provided with at least one flyweight (4), preferably two opposing flyweights (4), in which the resonator (1) includes a flexible guide connecting the oscillating mass (2) to the base (3), so as to be able to cause the oscillating mass (2) to oscillate about a center of rotation in a pendulum movement, the flexible guide comprising at least a first flexible blade (6) connecting the base (3) to the oscillating mass (2), the first flexible blade (6) comprising at least in part an electrically acuatable piezoelectric material for deforming the first flexible blade (6) and causing the oscillating mass (2) to oscillate.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] The electric motors commonly used in the manufacture of portable timepieces (e.g., wristwatches, pocket watches) are "Lavet" type rotary motors that operate on the principle of electromagnetic physics. This type of motor generally includes a stator with a coil attached and a magnetized rotor that rotates by shifting the phase of the coil.

[0003] However, in such motors, the resistance to high magnetic fields is limited. When the magnetic field exceeds a certain value, the motor stops. Generally, when the magnetic field is greater than 2 mT, the movement of the motor becomes abnormal.

[0004] Therefore, to avoid this problem, it is necessary to design a motor that operates on another physical principle.

[0005] For example, there is an electrostatic motor with comb teeth as described in Swiss Patent CH709512. However, the comb teeth occupy space and consume more energy than a "Lavet" type motor.

[0006] Motors based on the piezoelectric effect have also been developed, for example, in European Patent EP0587031. However, this motor is limited to actuating the calendar. Also, due to high power consumption and the risk of early wear, it cannot be used to drive the second hand, which usually requires the most energy.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention aims to provide a piezoelectric resonator, especially for a rotary piezoelectric motor, which can withstand high electromagnetic fields while maintaining low power consumption and small volume.

Means for Solving the Problem

[0008] To this end, the present invention relates to a piezoelectric resonator, especially for a piezoelectric rotary motor of a timepiece, the piezoelectric resonator comprising a fixed base and a pendulum extending around a vertical axis, the pendulum having at least one flyweight, preferably two flyweights on opposite sides.

[0009] The piezoelectric resonator comprises a flexible blade guide connecting the pendulum to the base, whereby the pendulum can be vibrated about the center of rotation so as to perform a pendulum motion, and the flexible guide comprises at least one first flexible blade connecting the base to the pendulum, and the present invention is innovative in that the first flexible blade at least partially comprises a piezoelectric material that can be electrically actuated to deform the first flexible blade and vibrate the pendulum.

[0010] A resonator having such a configuration can provide efficient motion. By actuating the piezoelectric material of the flexible blade, the flexible blade bends and the pendulum vibrates by rotating about the center of rotation. In this way, since only a little energy is required to actuate the flexible blade, the resonator vibrates the pendulum with little energy consumption.

[0011] Also, by selecting the resonance condition of the resonator at the natural frequency of the resonator, the piezoelectric resonator, and thus the motor, consumes little energy. By actuation in resonance, the amplitude can be increased with less energy.

[0012] Therefore, according to the application field of the piezoelectric resonator, the vibration motion can be transmitted to other mechanical parts, for example, the gears of the movement.

[0013] In a specific embodiment of the present invention, the center of rotation is arranged substantially at the center of the vibration weight, preferably at the center of gravity of the vibration weight.

[0014] In a specific embodiment of the present invention, the flexible guide comprises a second flexible blade connecting the vibration weight to the base or the fixed support. As a result, an elastic pivot of the RCC (Remote Center Compliance) type, which is an elastic rotary guide, can be obtained.

[0015] In a specific embodiment of the present invention, the second flexible blade at least partially includes a piezoelectric material that can be electrically actuated to deform the second flexible blade and vibrate the vibration weight.

[0016] In a specific embodiment of the present invention, the first flexible blade and the second flexible blade form an angle within a range of 30° to 150°, preferably within a range of 60° to 130°, more preferably within a range of 90° to 120°.

[0017] In a specific embodiment of the present invention, the first flexible blade and the second flexible blade do not intersect and extend from the central portion of the vibration weight to the eccentric portion of the base.

[0018] In a specific embodiment of the present invention, a third flexible blade is provided, and the second flexible blade and the third flexible blade do not intersect and extend from the central portion of the vibration weight to the eccentric portion of the base.

[0019] In a particular embodiment of the present invention, the second flexible blade and the third flexible blade form an angle within the range of 30° to 150°, preferably within the range of 60° to 130°, and more preferably within the range of 90° to 120°.

[0020] In a particular embodiment of the present invention, the first flexible blade is disposed between the second flexible blade and the third flexible blade.

[0021] In a particular embodiment of the present invention, the first flexible blade is closer to the second flexible blade than the third flexible blade.

[0022] In a particular embodiment of the present invention, the first flexible blade has a rigid portion.

[0023] In a particular embodiment of the present invention, the pendulum weight comprises a toggle pendulum bent in the shape of an elbow.

[0024] In a particular embodiment of the present invention, the first flexible blade is inclined and is connected to the end of an inertia block bent in the shape of an elbow.

[0025] In a particular embodiment of the present invention, the second flexible blade is substantially parallel to the longitudinal axis of the pendulum weight and is connected to the inside of the bend of the inertia block.

[0026] In a particular embodiment of the present invention, the first flexible blade and the second flexible blade form an angle within the range of 10° to 90°, preferably within the range of 30° to 60°.

[0027] In a particular embodiment of the present invention, the first flexible blade is U-shaped and is connected to the toggle pendulum of the pendulum weight.

[0028] In a particular embodiment of the present invention, the first flexible blade is arranged parallel to the longitudinal axis of the pendulum weight.

[0029] In a particular embodiment of the present invention, the second flexible blade is arranged on the side opposite to the first flexible blade with respect to the pendulum weight.

[0030] In a particular embodiment of the present invention, the piezoelectric resonators are arranged substantially in the same plane.

[0031] In a particular embodiment of the present invention, the piezoelectric resonators are configured to vibrate the pendulum weight at the natural vibration frequency of the piezoelectric resonators.

[0032] In a particular embodiment of the present invention, the piezoelectric resonators preferably comprise, for the most part, a single crystal or polycrystalline material that has a low conductivity, such as silicon, glass, ceramics, metal, and is obtained by an MEMS-type photolithography micromachining process or the like, and is non-magnetic.

[0033] In a particular embodiment of the present invention, the flexible guide is made as an integral single part.

[0034] The present invention further relates to a piezoelectric motor comprising such a piezoelectric resonator, particularly for a display device of a timepiece.

[0035] In a particular embodiment of the present invention, the piezoelectric motor preferably comprises at least one claw, which is preferably two claws, and a movable vehicle. The claw is attached to the pendulum weight of the piezoelectric resonator, whereby the movable vehicle is rotated in a first direction when the pendulum weight vibrates.

[0036] The present invention further relates to a timepiece movement comprising a gear transmission configured to rotate at least one needle, and a piezoelectric motor as described above configured to actuate this gear transmission.

[0037] By reading the following description, which is for illustrative purposes and not limiting, with reference to the accompanying drawings, other features and advantages will become apparent.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0039] Figures 1 to 6 show different versions of a piezoelectric resonator, particularly for use in a rotary motor. In particular, the motor can be used in a timepiece to drive a display device including a hand disposed on a dial. The piezoelectric resonators 1, 10, 20, 30, 40 preferably extend substantially within one plane.

[0040] In FIG. 1, the piezoelectric resonator according to the first embodiment has a base 3 which is here substantially triangular, preferably isosceles. The base 3 has two holes 11, enabling the base 3 to be assembled to a plate or a bridge, particularly in a movement for a portable timepiece.

[0041] This triangle has a main vertex and two vertices which are opposite to each other and off - center. This triangle has two equal sides and another side whose length is larger than the height, preferably at least twice as large, more preferably four to five times as large. Each of the two opposite vertices has a projection 5 extending towards the upper part of this triangle.

[0042] Also, the resonator 1 includes a pendulum 2. The pendulum 2 has a main arm, and two centrifugal weights 4 are arranged at the ends of this main arm. The arm has a stud 8 arranged at its center and facing the base 3. The arm is arranged in the tangential direction at the main vertex of the triangle. The arm is substantially straight except for a central region forming a triangular offset corresponding to the main vertex of the triangle. The stud 8 is arranged inside this triangular offset.

[0043] The pendulum 2 and the base 3 are preferably arranged in the same plane.

[0044] According to the present invention, the resonator includes a flexible blade guide that connects the vibration weight 2 to the base 3, whereby the vibration weight 2 can oscillate about the center of rotation so as to perform a pendulum motion. This center of rotation is located substantially at the center of the vibration weight 2, i.e., the center of the arm, preferably at the center of gravity of the vibration weight 2. As a result, an RCC (Remote Center Compliance) type elastic pivot, which is an elastic rotation guide, is formed.

[0045] The flexible guide has two flexible blades. The first flexible blade 6 and the second flexible blade 7 are connected to the same central portion of the vibration weight 2, in this case the stud 8. Also, 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 two protrusions 5.

[0046] The first flexible blade 6 and the second flexible blade 7 do not cross and extend from the stud 8 on the vibration weight 2 to the protrusion 5 on the base 3. In this way, each flexible blade 6, 7 connects the protrusion 5 on the base 3 to the stud 8 on the vibration weight, and this vibration weight extends along one of the equal sides of an isosceles triangle.

[0047] The first flexible blade 6 and the second flexible blade 7 form a non-zero angle therebetween, and the angle is in the range of 30° to 150°, preferably in the range of 60° to 130°, more preferably in the range of 90° to 120°.

[0048] Each of the flexible blades 6, 7 includes a piezoelectric material that can be actuated to oscillate the vibration weight relative to the base. Preferably, the piezoelectric material is disposed entirely on each of the flexible blades 6, 7.

[0049] For example, the flexible blade has a layer of piezoelectric material sandwiched between two electrode layers.

[0050] To actuate the flexible blades 6, 7, the projection 5 has a number of electrical contacts 9 that are connected to the electrode layer and receive a voltage to actuate the piezoelectric layer of the flexible blade.

[0051] The piezoelectric layer is preferably made of a crystalline or polycrystalline material, for example, of the KNN type ceramics (in the case of sodium potassium niobate) or PZT type ceramics (in the case of lead zirconate titanate), and the flexible blades 6, 7 have a thickness that allows their deformation.

[0052] Thus, by electrically activating the layer of the piezoelectric material, the flexible blades 6, 7 deform alternately laterally towards the center and outwards. This activation is generated by an alternating voltage.

[0053] By choosing to actuate the two flexible blades 6, 7 in antiphase by reversing the polarity of one blade with respect to the other, the pendulum performs small oscillations about the center of rotation corresponding to the point where the two flexible blades intersect, in this case the stud 8. In this way, the pendulum 2 oscillates and the two centrifugal weights 4 move laterally at a specific frequency, preferably the resonant frequency.

[0054] In the resonator 10 according to the second embodiment shown in FIG. 2, a flexible collar that is narrower than the blade is added. And the piezoelectric material is arranged only on the portions 18, 19 of the lengths of the flexible blades 16, 17. The remaining part of the resonator 10 is substantially the same as the previous design. Thus, the portions of the blades 16, 17 without the piezoelectric material are thinner than the portions with the piezoelectric material, preferably with a thickness 1 / 5 to 1 / 10 times.

[0055] The base 13 and the projection 25 are substantially the same as the first design.

[0056] The resonator 20 according to the third embodiment in FIGS. 3 and 4 shows a resonator to which a flexible guide with three flexible blades 26, 27, 28 is attached. The resonator is the same as the first two embodiments with respect to the shape of the base 23 and the protrusion 25.

[0057] The base 23 has a channel 21 that opens from the main vertex to the inside of the base 23. The channel 21 is bent in the base 23.

[0058] The first flexible blade 26 connects the stud of the pendulum weight 22 to the base 23 between the second flexible blade 27 and the third flexible blade 28.

[0059] The second flexible blade 27 and the third flexible blade 28 are configured like the flexible blades according to the first and second embodiments. The second flexible blade 27 and the third flexible blade 28 form a non-zero angle between them, and the angle is within the range of 30° to 150°, preferably within the range of 60° to 130°, more preferably within the range of 90° to 120°. In this embodiment, these two flexible blades do not contain a piezoelectric material. The second flexible blade 27 and the third flexible blade 28 are connected to the same central portion of the pendulum weight 22 and to the eccentric protrusions 25 on two opposite sides of the base 23. The second flexible blade 27 and the third flexible blade 28 do not intersect and extend from the central portion of the pendulum weight 22, which is a stud in this case, to the eccentric portion of the base 23.

[0060] The first flexible blade 26 is activated by an electrical contact (not shown) attached to the base 23.

[0061] The first flexible blade 26 extends within the bent channel 21 to a fixed point at the bottom of the channel 21. The first flexible blade 26 has a portion 29 with a piezoelectric material at the bottom of the bent channel 21 and a rigid portion 31 at the entrance of the channel 21. These two portions 29, 31 are separated by a flexible neck at the bent location.

[0062] Figure 4 is an enlarged view of Figure 3. The central zone of the first flexible blade 26 is eccentric by a non-zero distance r with respect to the intersection of the second flexible blade 27 and the third flexible blade 28. As a result, when the first flexible blade 26 is actuated, it alternately pulls the pendulum 22 to one side and then releases it, causing it to oscillate about the center of rotation passing through the intersection of the first two flexible blades 26, 27.

[0063] In the fourth embodiment shown in Figure 5, the pendulum 32 has a main arm, a first flyweight 34 at the first end, and a second flyweight 35 at the second end. This second flyweight 35 forms a rigid bend that bends under the main arm.

[0064] The resonator includes a flexible guide with a first flexible blade 36 that connects the pendulum 32 to the base 33 from the end of the bent elbow. The first flexible blade 36 extends within the inclined channel 39 to a second embedding point at the bottom of the inclined channel 39.

[0065] The flexible guide includes a second flexible blade 37 that extends parallel to the arm of the pendulum 32 from the first corner of the base 33 to an embedding point within the bent location of the pendulum 32. The second flexible blade 37 is disposed above the first flexible blade 36.

[0066] At the level of the first balance weight 34, the base 33 has a first embedding point corresponding to the second flexible blade 37 and a second embedding point connected to the first flexible blade 36 and arranged here at a position of 45° counterclockwise (not limited to this value). The second embedding point is located in the inclined channel 38 opening from the first corner of the base 33.

[0067] The first flexible blade 36 and the second flexible blade 37 further extend to form a non-zero angle within the range of 10° to 80°, preferably within the range of 30° to 60°, and more preferably within the range of 40° to 50°.

[0068] The two flexible blades 36, 37 contain a piezoelectric material and are arranged here on the entire second flexible blade 37 and on a part of the first flexible blade 36. The flexible blades 36, 37 are actuated in the same manner as in the previous embodiment using electrical contacts (not shown).

[0069] Although the configuration of this embodiment is different from other embodiments, the balance weight 32 vibrates in the same manner. That is, it vibrates about an axis located at the intersection of the neutral fibers of the two flexible blades 36, 37.

[0070] In the piezoelectric resonator 40 according to the fifth embodiment shown in FIG. 6, the balance weight 42 has an arm connecting the two centrifugal weights 44, 45. The base 43 has a rectangular shape.

[0071] The resonator 40 includes a U-shaped first flexible blade 46 connecting the balance weight 42 to the base 43. This U shape is arranged parallel to the arm and the base 43. The first end 48 of this U shape is connected to the base 43, and the second end 49 of the U shape, which is farther from the center than the first end 48, is connected to the weight 45 of the balance weight 42.

[0072] The U-shaped first flexible blade 46 preferably contains a piezoelectric material along its entire length.

[0073] The resonator further comprises a second flexible blade 47 that forms an active ratchet blade. The second flexible blade 47 is disposed on the other side of the arm from the first flexible blade 46. Preferably, the second flexible blade 47 does not contain any piezoelectric material.

[0074] By electrically actuating the first flexible U-shaped blade 46, the pendulum 42 and the centrifugal weights 44, 45 vibrate about the center of rotation. Preferably, the center of rotation is disposed at the center of gravity of the pendulum 42. The first flexible blade 46 is actuated by electrical contacts attached to a base 43 (not shown).

[0075] According to the above method, the resonators 1, 10, 20, 30 are preferably made mainly of single-crystalline or polycrystalline materials such as silicon, glass, ceramics, and metals.

[0076] The resonators 1, 10, 20, 30 are obtained, for example, by a MEMS (Micro-Electro-Mechanical System) type photolithography micromachining process. The rigidity, elasticity, and machining accuracy of such materials improve the resonance quality of the resonators 1, 10, 20, 30.

[0077] Also, the non-magnetic and low conductivity properties of some of such materials provide excellent resistance to large DC and AC magnetic fields.

[0078] Also, the resonators 1, 10, 20, 30 are configured to vibrate the pendulums 2, 12, 22, 32, 42 at the natural vibration frequencies of the resonators 1, 10, 20, 30, 40, thereby suppressing the energy consumption of the resonators, particularly by increasing the angular travel of the pendulums.

[0079] FIG. 7 shows an example of a rotary piezoelectric motor 50, particularly for a display device of a timepiece.

[0080] In particular, the motor can be used to drive a display device such as a hand disposed on a dial in a timepiece. The piezoelectric motor 50 is configured to be able to rotate and actuate a mechanical gear transmission of the display device.

[0081] The piezoelectric motor 50 includes a piezoelectric resonator according to the present invention, in this case, the piezoelectric resonator 30 according to the fourth embodiment shown in FIG. 5. Piezoelectric resonators according to other embodiments can also be used without changing the operation of the piezoelectric motor 50. The piezoelectric resonator 30 is assembled to the plate by its base 33.

[0082] The piezoelectric motor 50 further includes a toothed movable wheel 51 and two claws 52, 53 configured to rotate the movable wheel 51 in one direction. The movable wheel 51 preferably has circumferential teeth, which are preferably asymmetric teeth, thereby defining the direction of rotation. The movable wheel 50 is connected to a gear to which the hand of the display device is attached.

[0083] The first claw 52 is active and has a function of rotating the movable wheel 51 counterclockwise. The second claw 53 is passive and holds the movable wheel 51 when the movable wheel 51 rotates while the active first claw 52 is reset by the next tooth of the rotor.

[0084] Each of the claws 52, 53 has a flexible blade 54 at its end, which preferably has teeth 55 that are preferably asymmetric teeth.

[0085] The movement of the active first claw 52 causes the movable wheel 51 to rotate. This first claw 52 is attached to the pendulum 32 of the piezoelectric resonator 30. Therefore, when the resonator vibrates, the first claw 52 also vibrates, and thereby, depending on the position of the piezoelectric resonator with respect to the toothed movable wheel 51, the first claw 52 pushes or pulls the toothed movable wheel 51 in the first direction.

[0086] The second pawl 53 is directly assembled to the base or the base bridge, and more preferably, is integral with the base 30, thereby suppressing positioning errors caused by a series of assembly tolerances. The function of this second pawl 53 is to prevent the gear from rotating in a direction opposite to the first direction. The teeth 55 of the second pawl 53 are configured to cooperate with the asymmetric teeth to allow the movable wheel 51 to rotate in the first direction and to prevent the movable wheel 51 from rotating in the opposite direction.

[0087] For this purpose, the flexible arms 54 of the pawls 52, 53 are in a relaxed and straight position when the teeth 55 are engaged in the recesses of the tooth row of the gear 51, and are bent and closed when pushed outward by the tooth row when the gear 51 rotates in the first direction.

[0088] In the case of a portable watch, the resonant frequency or natural frequency of the motor 50 is adapted to match the frequency of the crystal used to adjust the rate of the movement. An excitation frequency corresponding to a divisor of the frequency of the crystal, which is usually 32764 Hz, is selected. For example, a frequency of 128 Hz is selected. The frequency of the motor 50 is preferably adjusted and tuned to the excitation frequency such that its vibration amplitude does not fall below 90 - 95% of the maximum amplitude.

[0089] Optionally, the second pawl 53 can be configured to function as a pitch sensor to determine the rotational speed or rotational speed of the movable wheel 51. For this purpose, a piezoelectric material connected to a counting unit is attached to the flexible arm 54 of the second pawl 53. Each time the second pawl 53 is bent, the counting unit registers one tooth's worth of rotation of the movable wheel 51.

[0090] It will be understood that various changes and / or improvements and / or combinations, which are obvious to those skilled in the art, can be made to the various embodiments of the present invention described above without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A piezoelectric resonator (1, 10, 20, 30, 40) for a piezoelectric rotary motor, said piezoelectric resonator (1, 10, 20, 30, 40) comprising a fixed base (3, 13, 23, 33, 43) and a pendulum (2, 12, 22, 32, 42) extending around a major axis parallel to said base, said pendulum (2, 12, 22, 32, 42) having a main arm extending along said major axis and swing weights (4, 14, 24, 34, 35, 44, 45) at both ends of said main arm, said piezoelectric resonator (1, 10, 20, 30, 40) comprising a flexible blade guide connecting said pendulum (2, 12, 22, 32, 42) to said base (3, 13, 23, 33, 43), whereby said pendulum (2, 12, 22, 32, 42) can be vibrated about a center of rotation so as to perform a pendulum motion, said flexible blade guide comprising at least one first flexible blade (6, 16, 26, 36, 46) connecting said base (3, 13, 23, 33, 43) to said pendulum (2, 12, 22, 32, 42), said first flexible blade (6, 16, 26, 36, 46) at least partially including a piezoelectric material electrically actuatable to deform said first flexible blade (6, 16, 26, 36, 46) and vibrate said pendulum (2, 12, 22, 32, 42), said flexible blade guide comprising a second flexible blade (7, 17, 27, 37, 47) connecting said pendulum (2, 12, 22, 32, 42) to said base (3, 13, 23, 33, 43) A piezoelectric resonator characterized by the above.

2. said center of rotation being substantially located at the center of said pendulum (2, 12, 22, 32, 42) The piezoelectric resonator according to claim 1, characterized by the above.

3. The second flexible blade (7, 17, 37) at least partially includes a piezoelectric material that is electrically actuatable to deform the second flexible blade (7, 17, 37) and vibrate the pendulum weight (2, 12, 22, 32, 42). The piezoelectric resonator according to claim 1, characterized in that.

4. The first flexible blade (6, 16, 26, 36, 46) and the second flexible blade (7, 17, 27, 37, 47) form an angle within the range of 30° to 150°. The piezoelectric resonator according to claim 3, characterized in that.

5. The first flexible blade (6, 16) and the second flexible blade (7, 17) do not intersect and extend from the central portion of the pendulum weight (2, 12) to the eccentric portion of the base (3, 13). The piezoelectric resonator according to claim 4, characterized in that.

6. Comprising a third flexible blade (28), The second flexible blade (27) and the third flexible blade (28) do not intersect and extend from the central portion of the pendulum weight (2, 12) to the eccentric portion of the base (3, 13). The piezoelectric resonator according to claim 1, characterized in that.

7. The second flexible blade (27) and the third flexible blade (28) form an angle within the range of 30° to 150°. The piezoelectric resonator according to claim 6, characterized in that.

8. The first flexible blade (26) is disposed between the second flexible blade (27) and the third flexible blade (28). The piezoelectric resonator according to claim 7, characterized in that.

9. The first flexible blade (26) is closer to the second flexible blade (27) than the third flexible blade (28). The piezoelectric resonator according to claim 8, characterized in that.

10. The first flexible blade (26) further has a rigid portion (31). The piezoelectric resonator according to claim 8, characterized in that.

11. The vibration weight (32) includes a trigger weight (35) bent in the shape of an elbow. The piezoelectric resonator according to claim 1, characterized in that.

12. The first flexible blade (36) is obliquely oriented and is connected to the end of the trigger weight (35) bent in the shape of an elbow. The piezoelectric resonator according to claim 11, characterized in that.

13. The second flexible blade (37) is substantially parallel to the major axis and is connected to the inside of the elbow of the trigger weight (35). The piezoelectric resonator according to claim 11, characterized in that.

14. The first flexible blade (36) and the second flexible blade (37) form an angle within the range of 10° to 90°. The piezoelectric resonator according to claim 11, characterized in that.

15. The first flexible blade (46) is U-shaped and is connected to the trigger weight (45) of the vibration weight (42). The piezoelectric resonator according to claim 1, characterized in that.

16. The first flexible blade (46) is arranged parallel to the major axis. The piezoelectric resonator according to claim 15, characterized in that.

17. Arranged in substantially the same plane. The piezoelectric resonator according to claim 1, characterized in that...

18. The vibration weight (2, 12, 22, 32, 42) is configured to vibrate at the natural vibration frequency of the piezoelectric resonator (1, 10, 20, 30, 40). The piezoelectric resonator according to claim 1, characterized in that...

19. Comprising a single crystal or polycrystalline material that is mostly low in conductivity and non-magnetic. The piezoelectric resonator according to claim 1, characterized in that...

20. A piezoelectric motor for a display device of a timepiece, Comprising the piezoelectric resonator (1, 10, 20, 30, 40) according to claim 1. The piezoelectric motor is characterized in that...

21. The piezoelectric motor includes at least one pawl (52) and a movable vehicle (51), The pawl (52) is attached to the vibration weight (32) of the piezoelectric resonator (1), whereby when the vibration weight (32) vibrates, the movable vehicle (51) is rotated in a first direction. The piezoelectric motor according to claim 20, characterized in that...

22. A timepiece comprising a movement for a timepiece having a gear transmission configured to rotate at least one hand, The timepiece comprises the piezoelectric resonator (1, 10, 20, 30, 40) according to claim 1, or the piezoelectric motor (50) according to claim 20 configured to actuate the gear transmission. The timepiece is characterized in that...

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