An ultra-thin piezoelectric ceramic motor

Abstract

The present invention discloses an ultra-thin piezoelectric ceramic motor comprising a piezoelectric bimorph comprising an upper piezoelectric ceramic sheet and a lower piezoelectric ceramic sheet, with a metal substrate disposed between the upper and lower piezoelectric ceramic sheets. A FPCB with electrodes is disposed on both the upper and lower surfaces of the metal substrate. The electrodes of the upper and lower piezoelectric ceramic sheets align with the electrodes of the FPCB to achieve electrical interconnection. A mass block is disposed on one side of the piezoelectric bimorph, fixedly connected to the metal substrate, with a gap between the mass block and both the upper and lower piezoelectric ceramic sheets. This invention provides a piezoelectric ceramic motor with high acceleration and ease of installation, eliminating the influence of the rigidity of the piezoelectric ceramic motor's mounting structure on its vibration and expanding the application range of ceramic motors.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to an ultra-thin piezoelectric ceramic motor. Background Art

[0002] With the advancement of technology, most products with displays or that require pressure, such as mobile phones, computers, home appliances, and automobiles, require user interaction. This goes beyond input control and often requires feedback. For a long time, the feedback signals of electronic products have been sound and light. With the study of haptics, tactile feedback has gradually become the third language of communication between electronic products and humans. Haptic feedback technology involves the user providing a press or touch signal. The signal is interpreted by the MCU and transmitted to the chip, which then begins to operate. Depending on the scenario, it sends different drives to the motor, causing the motor to vibrate, giving the user a rich sense of vibration.

[0003] There are three common types of motors on the market: rotor motors, linear motors, and piezoelectric ceramic motors. The working principle of the rotor motor tactile vibrator is similar to that of a DC motor, which relies on rotation to generate vibration, so vibration can be felt in the Y-axis and Z-axis directions. However, in many applications, only vibration in a certain direction is required. In this way, vibration in other directions becomes a waste of energy, and the rotor motor has a slow response speed, weak vibration intensity, and a rough vibration experience, and high power consumption. The linear motor is mainly a spring system composed of a spring, a mass block, and a coil. It has a fast response speed, high vibration intensity, a delicate vibration experience, low power consumption, and low acoustic noise, but its vibration intensity is limited by the internal spring resonant frequency, and the vibration drive is The sine wave frequency of the vibrator must be near the resonant frequency, and the bandwidth is very narrow, preferably within ±2Hz. A slight deviation in the resonant frequency will significantly reduce the vibration intensity and weaken the vibration effect. Piezoelectric ceramic motors are made of piezoelectric ceramics. When voltage is loaded on the piezoelectric ceramics, the ceramics will rapidly deform. This deformation of the piezoelectric ceramic material makes the piezoelectric ceramic motor a tactile vibrator with faster response speed and more precise vibration control. Based on the resonant frequency characteristics of the piezoelectric device, the driving frequency range of the piezoelectric ceramic motor is wider, and the acoustic noise is smaller. The vibration experience is stronger and more realistic than that of the rotor motor and linear motor.

[0004] As a new type of actuator, piezoelectric ceramic motors have attracted widespread attention both domestically and internationally for their advantages, including high torque at low speed, high static holding torque, fast response, compact size and weight, simple structure, and resistance to electromagnetic interference. They have been applied in a wide range of fields. However, their application is currently limited by the relatively weak vibration acceleration of commercially available piezoelectric ceramic motors and the significant impact of mounting structure rigidity. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the existing technology and propose an ultra-thin piezoelectric ceramic motor, providing a piezoelectric ceramic motor with large acceleration and easy installation, breaking the influence of the rigidity of the piezoelectric ceramic motor installation structure on its vibration, and expanding the application range of the ceramic motor.

[0006] The technical solution for achieving the purpose of the present invention is:

[0007] An ultra-thin piezoelectric ceramic motor includes a piezoelectric bimorph comprising an upper piezoelectric ceramic sheet and a lower piezoelectric ceramic sheet. A metal substrate is disposed between the upper and lower piezoelectric ceramic sheets. An FPCB with electrodes is provided on both the upper and lower surfaces of the metal substrate. The electrodes of the upper and lower piezoelectric ceramic sheets align with the electrodes of the FPCB to achieve electrical interconnection. A mass block fixedly connected to the metal substrate is provided on one side of the piezoelectric bimorph, with a gap provided between the mass block and both the upper and lower piezoelectric ceramic sheets.

[0008] Furthermore, in order to facilitate connection with the mass block, connecting pieces are provided on the front and rear sides of the metal substrate, and the mass block is fixedly connected to the connecting pieces by a laser spot welding process.

[0009] Furthermore, in order to meet the rigidity requirements of different products, the metal substrate is made of stainless steel, aluminum alloy, titanium alloy or nickel alloy.

[0010] Furthermore, in order to ensure that the motor has large displacement and acceleration, the upper piezoelectric ceramic sheet and the lower piezoelectric ceramic sheet are shaped as elongated rectangles with a relatively large length to width ratio.

[0011] Furthermore, depending on the size of the customer's driving voltage, the upper piezoelectric ceramic sheet and the lower piezoelectric ceramic sheet are made of single-layer or multi-layer ceramics. In order to ensure ultra-thinness and adapt to the installation space with a small gap, the total thickness of the upper piezoelectric ceramic sheet and the total thickness of the lower piezoelectric ceramic sheet are both controlled at 0.15~0.4mm. When multi-layer ceramics are used, the thickness of each layer of ceramic is 40~80um.

[0012] Furthermore, in order to ensure that the piezoelectric ceramic sheet has larger piezoelectric coefficients D33 and D31, the ceramic formula of the upper piezoelectric ceramic sheet and the lower piezoelectric ceramic sheet adopts the PTZ5 series.

[0013] Furthermore, in order to facilitate the connection between the mass block and the metal substrate, the mass block includes a front block and a rear block symmetrically arranged in front and behind the piezoelectric dual chip, and an intermediate block arranged above the piezoelectric dual chip. The front block and the rear block are fixedly connected through the intermediate block, and the front block and the rear block are respectively fixedly connected to the metal substrate.

[0014] Furthermore, in order to ensure that the mass block can increase the vibration impulse of the piezoelectric body, the material of the mass block is selected to be tungsten steel or stainless steel with a relatively high density.

[0015] Furthermore, in order to prevent the thickness of the entire motor from being uncontrollable due to welding of the external circuit to the motor electrodes, the FPCB is provided with electrode pins extending to the outside.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects:

[0017] (1) The present invention forms a piezoelectric dual-chip by installing an upper piezoelectric ceramic sheet and a lower piezoelectric ceramic sheet on the upper and lower metal substrates respectively. When an AC voltage is applied, the internal polarization state of the piezoelectric ceramic sheet changes, resulting in expansion and contraction deformation in the length and thickness directions. Since the electrodes of the upper and lower piezoelectric ceramic sheets are matched and aligned with the electrodes of the FPCB, electrical interconnection is achieved. When voltage is applied, one stretches and the other contracts. Under the action of the metal substrate, bending vibration occurs, thereby generating a sense of vibration with a fast response speed. By adding a mass block, the vibration impulse of the piezoelectric body is increased, the energy of the piezoelectric vibration is transmitted, and the acceleration value of the motor is increased. With the structural design of the present invention, during installation, the two ends of the metal substrate are directly fixedly connected to the load to achieve hard contact, thereby expanding the application range of the piezoelectric ceramic motor.

[0018] (2) The metal substrate of the present invention is provided with connecting plates on the front and back sides to facilitate connection with the mass block. At the same time, laser spot welding is used to fix the connecting plates and the mass plate to ensure that the two are firmly connected.

[0019] (3) The material of the metal substrate of the present invention is stainless steel, aluminum alloy, titanium alloy or nickel alloy, which can be selected according to the rigidity requirements of different products, and has a wider range of applications.

[0020] (4) The upper and lower piezoelectric ceramic sheets of the present invention are shaped like elongated rectangles with a relatively large length-to-width ratio. When an AC voltage is applied, the piezoelectric ceramic sheets undergo significant expansion and contraction deformation in the length and thickness directions, thereby ensuring that the motor has large displacement and acceleration.

[0021] (5) The piezoelectric ceramic sheet of the present invention can be designed in single or multi-layer to meet the needs of different customers' driving voltages and has a wide range of applications. At the same time, the thickness is controlled at 0.15 to 0.4 mm, and the ultra-thin design is adopted, which is also suitable for installation spaces with very small gaps.

[0022] (6) The ceramic formula of the piezoelectric ceramic sheet of the present invention adopts the PTZ5 series, which has large piezoelectric coefficients D33 and D31 and excellent piezoelectric performance.

[0023] (7) The mass block of the present invention is connected to the front block and the rear block through the middle block. The front block and the rear block are fixedly connected to the metal substrate respectively, which is convenient for assembly.

[0024] (8) The material of the mass block of the present invention is tungsten steel or stainless steel, which has a high density, thereby ensuring that the mass block can increase the vibration impulse of the piezoelectric body.

[0025] (9) The FPCB of the present invention is provided with electrode pins extending to the outside, which can be directly connected to the external circuit, thereby avoiding the welding of the external circuit and the motor electrode, which would cause the thickness of the entire motor to be uncontrollable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 It is the front view of the present invention;

[0028] Figure 2 A top view of the present invention;

[0029] Figure 3 A bottom view of the present invention;

[0030] Figure 4 A top view of the piezoelectric ceramic sheet of the present invention;

[0031] Figure 5 A bottom view of the piezoelectric ceramic sheet of the present invention;

[0032] Figure 6 Schematic diagram of the structure of the metal substrate of the present invention;

[0033] Figure 7 Schematic diagram of the structure of the FPCB of the present invention;

[0034] Figure 8 This is a schematic diagram of the acceleration test points after the present invention is installed in a mobile phone.

[0035] The reference numerals in the accompanying drawings are:

[0036] Upper piezoelectric ceramic sheet 1, upper piezoelectric ceramic sheet first contact area 11, upper piezoelectric ceramic sheet second contact area 12, upper piezoelectric ceramic sheet third contact area 13, insulating tape 14, lower piezoelectric ceramic sheet 2, metal substrate 3, connecting sheet 31, FPCB 4, electrode pins 41, FPCB first contact area 42, FPCB second contact area 43, mass block 5, front block 51, rear block 52, and middle block 53. DETAILED DESCRIPTION

[0037] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0038] (Example 1)

[0039] like Figures 1 to 7 The ultra-thin piezoelectric ceramic motor shown in the figure comprises an upper piezoelectric ceramic sheet 1 and a lower piezoelectric ceramic sheet 2 of identical structure, with a metal substrate 3 positioned between them. The upper and lower piezoelectric ceramic sheets 1 and 2 are bonded to the metal substrate 3 with glue to form a piezoelectric bimorph. A mass block 5 is positioned on the upper surface of the piezoelectric bimorph. A gap is provided between the mass block 5 and both the upper and lower piezoelectric ceramic sheets 1 and 2 to prevent contact. The mass block 5 is also fixedly connected to the metal substrate 3. FPCB 4, a double-sided substrate with electrodes, is attached to both the upper and lower surfaces of the metal substrate 3. The electrodes of the upper and lower piezoelectric ceramic sheets 1 and 2 mate with those of the FPCB 4, achieving electrical interconnection. Specifically, the upper piezoelectric ceramic sheet 1 includes a first contact area 11 on the upper surface, and second and third contact areas 12, 13 on the lower surface. An insulating strip 14 is provided between the second and third contact areas 12, 13, separating the positive and negative electrodes of the piezoelectric ceramic sheet. The FPCB 4 includes a first contact area 42 and a second contact area 43. The connection between the upper surface of the FPCB 4 and the upper piezoelectric ceramic sheet 1 is as follows: the first contact area 42 is connected to the second contact area 12, and the first contact area 42 is electrically connected to the metal substrate 3. The second contact area 43 is connected to the third contact area 13, and the third contact area 13 is interconnected with the first contact area 11, while the third contact area 13 is disconnected from the metal substrate 3. The connection between the FPCB4 on the lower surface and the lower piezoelectric ceramic sheet 2 is the same, and finally an ultra-thin piezoelectric ceramic motor with simple structure and reliable performance is obtained. The hard contact between the motor and the load is achieved by gluing the left and right ends of the metal substrate 3.

[0040] The upper and lower piezoelectric ceramic sheets 1 and 2 are single-layer ceramic sheets with a thickness of 0.23mm. Their ultra-thin design accommodates installations with tight clearances. The PTZ5 series ceramic formulation boasts large piezoelectric coefficients D33 and D31, resulting in superior piezoelectric performance. The upper and lower piezoelectric ceramic sheets 1 and 2 are symmetrically attached to the upper and lower surfaces of the metal substrate 3. They are rectangular in shape, with a large aspect ratio, measuring 50×6×0.23mm. When voltage is applied, the length and thickness of the piezoelectric ceramic sheets change significantly, ensuring the motor's high displacement and acceleration.

[0041] The metal substrate 3 is made of stainless steel, is longer than the piezoelectric ceramic, and measures 62×6×0.2mm. Connecting plates 31 are symmetrically positioned on its front and back sides. The mass block 5 is also made of stainless steel, weighing 2.5g. With its high density, the small mass block 5 can increase the vibration impulse of the piezoelectric element. The mass block 5 comprises a front block 51 and a rear block 52 of identical structure, symmetrically positioned in front and behind the piezoelectric bimorph, and an intermediate block 53 positioned above the piezoelectric bimorph. The front and rear blocks 51 and 52 are fixedly connected by the intermediate block 53. The sides of the front and rear blocks 51 and 52, located near the piezoelectric bimorph, are provided with grooves that mate with the connecting plates 31. When installing the mass block 5, the connecting plates 31 of the metal substrate 3 are inserted into the grooves for self-assembly. The connecting plates 31 are then fixedly connected to the mass block 5 via laser spot welding. This connection method not only facilitates assembly but also ensures a secure connection. The mass block 5 adopts a flat design, significantly reducing its thickness and meeting the requirements of an ultra-thin design.

[0042] In order to further ensure the ultra-thin design of the motor, the FPCB 4 of this embodiment is provided with electrode pins 41 extending to the outside to prevent the external circuit from being directly welded to the motor electrodes, which would cause the thickness of the entire motor to be uncontrollable.

[0043] The operating principle of this embodiment is as follows: When an AC voltage is applied, the internal polarization state of the piezoelectric ceramic changes, causing expansion and contraction in both length and thickness. Because the electrodes of the upper and lower piezoelectric ceramics align with those of the FPCB, achieving electrical interconnection, when voltage is applied, one piezoelectric ceramic extends while the other contracts. This, under the action of the metal substrate 3, generates bending vibrations, producing a sense of vibration and providing a fast response. The addition of a mass block 5 increases the vibration impulse of the piezoelectric element, enabling the energy of the piezoelectric vibration to be transmitted, thereby increasing the acceleration of the motor. With the structural design of this embodiment, when the motor is installed, the left and right ends of the metal substrate 3 are simply fixed to the load, achieving hard contact, thus expanding the application range of the piezoelectric ceramic motor.

[0044] The motor of Example 1 was loaded into the back of a mobile phone with a mass of 220 g, and the mobile phone was placed on the sponge. The accelerometers were placed at nine positions on the top, middle and bottom of the mobile phone, as shown in the figure. Figure 8 As shown, the motor is driven with a 100Vpp sine wave, and then the acceleration values ​​of various positions at different frequencies are tested. The specific values ​​are shown in Table 1. The acceleration values ​​of existing mobile phone motors measured under the same conditions are shown in Table 2.

[0045]

[0046]

[0047]

[0048] (Example 2)

[0049] The structure of Example 2 is similar to that of Example 1, except that the upper and lower piezoelectric ceramic sheets 1 and 2 in Example 2 are single-layer ceramics with dimensions of 33 × 3.8 × 0.18 mm, the metal substrate 3 is made of titanium alloy and measures 35 × 4 × 0.15 mm, and the mass is made of tungsten steel with a mass of 2.0 g. The acceleration values ​​measured in Example 2 are shown in Table 3.

[0050]

[0051]

[0052] (Example 3)

[0053] The structure of Example 3 is similar to that of Example 1, except that the upper and lower piezoelectric ceramic sheets 1 and 2 in Example 3 are made of multilayer ceramic, measuring 40 × 2.8 × 0.4 mm, with a total of eight layers, each 50 μm thick. The metal substrate 3 is made of stainless steel, measuring 45 × 3 × 0.15 mm. The mass block is made of tungsten steel and has a mass of 3.0 g. The acceleration values ​​measured in Example 3 are shown in Table 4.

[0054]

[0055] In summary, the ultra-thin piezoelectric ceramic motor of the present invention can achieve a relatively high acceleration while maintaining a rigid mounting structure, thus breaking the limitations of conventional piezoelectric ceramic motors.

[0056] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ultra-thin piezoelectric ceramic motor, characterized by: The piezoelectric bimorph comprises an upper piezoelectric ceramic sheet (1) and a lower piezoelectric ceramic sheet (2); a metal substrate (3) is provided between the upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2); an FPCB (4) with an electrode design is provided on the upper and lower surfaces of the metal substrate (3); the electrodes of the upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2) match the electrodes of the FPCB (4) to achieve electrical interconnection; a mass block (5) fixedly connected to the metal substrate (3) is provided on one side of the piezoelectric bimorph; a gap is provided between the mass block (5) and the upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2); The upper piezoelectric ceramic sheet (1) comprises a first contact area (11) of the upper piezoelectric ceramic sheet provided on the upper surface, a second contact area (12) of the upper piezoelectric ceramic sheet provided on the lower surface, a third contact area (13) of the upper piezoelectric ceramic sheet, and an insulating tape (14) provided therebetween for separating the positive and negative electrodes of the piezoelectric ceramic sheet. The FPCB (4) is provided with a first FPCB contact area (42) and a second FPCB contact area (43), wherein the first FPCB contact area (42) is connected to the second contact area (12) of the upper piezoelectric ceramic sheet, and the first FPCB contact area (42) is conductively connected to the metal substrate (3); the second FPCB contact area (43) is connected to the third contact area (13) of the upper piezoelectric ceramic sheet, the third contact area (13) of the upper piezoelectric ceramic sheet is interconnected with the first contact area (11) of the upper piezoelectric ceramic sheet, and the third contact area (13) of the upper piezoelectric ceramic sheet is disconnected from the metal substrate (3); The mass block (5) comprises a front block (51) and a rear block (52) symmetrically arranged in front and behind the piezoelectric bimorph, and an intermediate block (53) arranged above the piezoelectric bimorph. The front block (51) and the rear block (52) are fixedly connected via the intermediate block (53). The front block (51) and the rear block (52) are fixedly connected to the metal substrate (3).

2. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: Connecting pieces (31) are provided on the front and rear sides of the metal substrate (3), and the mass block (5) is fixedly connected to the connecting pieces (31) through a laser spot welding process.

3. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The metal substrate (3) is made of stainless steel, aluminum alloy, titanium alloy or nickel alloy.

4. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2) are in the shape of an elongated rectangle.

5. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2) are made of single-layer or multi-layer ceramics with a thickness of 0.15 to 0.4 mm.

6. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The ceramic formula of the upper piezoelectric ceramic sheet (1) and the lower piezoelectric ceramic sheet (2) adopts the PTZ5 series.

7. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The mass block (5) is made of tungsten steel or stainless steel.

8. The ultra-thin piezoelectric ceramic motor according to claim 1, characterized in that: The FPCB (4) is provided with electrode pins (41) extending to the outside.

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