Four-link direct-push piezoelectric linear motor

Abstract

The present invention provides a four-link direct-push piezoelectric linear motor, which is composed of a stator, a sliding base, a preload mechanism, a mover and a base. The stator is composed of two four-link assemblies, which are composed of a four-link mechanism, a laminated piezoelectric ceramic, a preload spring, an adjustment stud and a driving foot; the stator is fixed to the sliding base by bolts, and the sliding base is installed on the base by cross rollers and guide rail fixing blocks thereof; the preload mechanism provides an adjustable preload for the piezoelectric linear motor, which is transmitted to the contact surface between the stator driving foot and the mover through the sliding base, and applies electrical signals with a phase difference of 90° to the two groups of laminated piezoelectric ceramics of the motor respectively, so that the alternating driving of the two feet of the motor can be realized.

Description

Technical Field

[0001] The present invention relates to the field of non-resonant piezoelectric linear motors, and in particular to the field of piezoelectric precision actuation technology. Background Art

[0002] Piezoelectric linear motors are different from traditional electromagnetic motors. They use the inverse piezoelectric effect of piezoelectric elements to convert the micron-level vibration generated by the piezoelectric element exciting the elastic body into the linear motion of the actuator through friction coupling. Piezoelectric linear motors have the advantages of fast response, high precision, and anti-electromagnetic interference. They have been applied in many cutting-edge technology fields such as ultra-precision machining, optical precision engineering, aerospace, electronics, and biomedicine.

[0003] According to the different stator vibration modes, piezoelectric linear motors can be divided into two types: resonant and non-resonant. Among them, the resonant piezoelectric linear motor is very sensitive to temperature and preload, but changes in the fixed boundary will affect the performance of this type of piezoelectric linear motor; and the non-resonant piezoelectric linear, when excited by low-frequency electrical signals, is more stable and reliable than the resonant type. According to the actuation principle, non-resonant piezoelectric linear motors can be divided into: inertial impact type (CN111969889A, 2020-11-20), inchworm type (CN210093126U, 2020-02-18), parasitic type (CN209389958, 2019-09-13), alternating drive type (CN112737401A, 2021-04-30), etc.

[0004] At present, non-resonant piezoelectric linear motors still have problems such as small stroke, small output thrust, and inability to work properly after wear. Their performance has not yet reached the requirements for large-scale industrial use. The reason is that the existing solutions have high requirements for processing and assembly accuracy. Since the output amplitude of the piezoelectric linear motor is at the micron level, the parallelism of the mover installation and fixation is extremely high, but assembly errors are difficult to avoid, which leads to a shorter motor stroke. In addition, the stator of the piezoelectric motor often adopts an integrated design, that is, the drive foot and the stator are a whole. When the motor is worn, the entire stator can only be replaced, which increases the cost of using the piezoelectric linear motor. Summary of the invention

[0005] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a four-link direct-push piezoelectric linear motor, which has the advantages of large stroke, large thrust, high displacement accuracy, wear resistance, etc.

[0006] The present invention adopts the following technical solution:

[0007] The four-link direct-push piezoelectric linear motor is composed of a stator, a sliding base, a pre-stressing mechanism, a mover and a base. The stator is fixedly mounted on the sliding base by bolts. The movement direction of the sliding base is perpendicular to the movement direction of the mover. The sliding base is mounted on the base through the cross roller guide rails and the guide rail fixing blocks thereon. The stator contacts the side of the mover through its driving foot. The pre-stressing mechanism is mounted on the base and connected to the sliding base. The pre-stressing force is transmitted to the contact surface of the stator driving foot and the mover through the sliding base, thereby providing pre-stressing force for the piezoelectric linear motor.

[0008] Further, the stator includes a four-bar linkage assembly, which is composed of a four-bar linkage, a laminated piezoelectric ceramic, a preload spring, an adjustment stud, and a driving foot;

[0009] The four links inside the four-bar linkage are connected to each other by flexible hinges, the laminated piezoelectric ceramic is installed in the four-bar linkage, and the preload spring is also installed in the four-bar linkage. One end of the adjusting stud hooks the preload spring, and the other end cooperates with the nut on the four-bar linkage and extends out of the four-bar linkage. The preload force is adjusted by adjusting the length of the locking thread on the adjusting stud. The driving foot is connected to the four-bar linkage and is located above the laminated piezoelectric ceramic.

[0010] Furthermore, the adjusting stud is provided with a triangular bevel, and the driving foot is provided with a chip removal groove.

[0011] Furthermore, the sliding base is composed of two stator connecting blocks, a base body, two sets of cross roller guide rails, two guide rail fixing blocks, two guide rail adjusting blocks and two adjusting bolts.

[0012] The sliding base is an axisymmetric structure. The stator connection block is installed on the base body. The left part of the sliding base:

[0013] One of the cross roller guide rails is fixed on the base body, and the other is installed on the guide rail fixing block, so that the sliding base can only slide relative to the bottom plate along the vertical direction of the mover movement.

[0014] The guide rail adjusting block and the adjusting bolt are installed on one side of the guide rail fixing block, and the parallelism of the cross roller guide rail is adjusted by rotating the adjusting bolt to lock the thread length.

[0015] The guide rail fixing block and the guide rail adjusting block are both installed on the base, and the structure of the right side of the sliding base is the same as that of the left side.

[0016] Furthermore, the preload mechanism is composed of a compression spring, a guide, a differential head, and a differential head support. The compression spring is installed on the guide, and the guide is connected to the differential head support through the differential head. The guide limits the swing of the compression spring, and the preload is adjusted by adjusting the elongation of the differential head. The differential head support is fixed to the base by bolts. When an electrical signal with a phase difference of 90° is applied to the two groups of laminated piezoelectric ceramics, the two stator drive feet I and stator drive feet II of the stator will produce alternating actuation.

[0017] Furthermore, the stator is composed of a four-bar assembly I and a four-bar assembly II, the four-bar assembly I includes an adjusting stud I and a driving foot I, and the four-bar assembly II includes an adjusting stud II and a driving foot II. The four-bar assembly I and the four-bar assembly II of the stator are respectively installed on the left and right stator connecting blocks by bolts.

[0018] Preferably, the stator is composed of a four-bar connecting assembly I, a four-bar connecting assembly II, a four-bar connecting assembly III, and a four-bar connecting assembly IV, there are two sliding bases, and there are two pre-compression mechanisms.

[0019] The left side of the mover is connected to the four-bar assembly III and the four-bar assembly IV of the stator II, the stator II is installed on the left sliding base, the left preloading mechanism is connected to the left sliding base, the right side of the mover is connected to the four-bar assembly I and the four-bar assembly II of the stator I, the stator I is installed on the right sliding base, and the right sliding base is connected to the right preloading mechanism. When the same electrical signal is applied to the laminated piezoelectric ceramics of the four-bar assembly I and III, and the four-bar assembly II and IV laminated piezoelectric ceramics are applied with a phase difference of 90°, the four stator driving feet I and III of the stator and the stator driving feet II and IV will produce alternating motions.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a four-link direct-push piezoelectric linear motor. The stator adopts a four-link flexible mechanism to amplify the output displacement of the laminated piezoelectric ceramics, increase the motor displacement output to reduce the requirement for the parallelism of the guide rail, tighten the four-link mechanism by a pre-tightening spring, realize the pre-tightening of the laminated piezoelectric ceramics, and reasonably use the internal space of the four-link mechanism to make the entire stator structure compact. The stator adopts a modular design, and the two four-link components have the same structure and function, which is convenient for motor processing and provides the possibility of mass production.

[0022] The present invention provides a four-link direct-push piezoelectric linear motor, wherein a preload mechanism provides an adjustable preload force for the motor. When the motor is worn after working for a period of time, a sliding base and a preload mechanism can compensate the motor, and always keep the stator drive foot in contact with the mover, so that the motor can continue to work normally, thereby improving the wear resistance of the motor.

[0023] The present invention provides a four-link direct-push piezoelectric linear motor. During the operation of the motor, the contact area between its driving foot and the mover remains unchanged, thereby avoiding slipping caused by relative sliding. A drainage groove is provided on the driving foot to avoid waste chips generated by motor wear from adhering to the contact surface, thereby making the motor movement more stable. In addition, the driving foot can be removed and replaced separately after being worn, thereby reducing the use cost of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a three-dimensional diagram of a four-bar direct-push piezoelectric linear motor;

[0025] Figure 2 It is a top view of a four-bar direct-push piezoelectric linear motor;

[0026] Figure 3(a), Figure 3(b), and Figure 3(c) are structural diagrams of the stator four-bar linkage assembly of a piezoelectric motor;

[0027] Figure 4 This is a structural diagram of the sliding base of the piezoelectric motor;

[0028] Figure 5 This is the structural diagram of the piezoelectric motor preloading mechanism;

[0029] Figure 6 It is the excitation signal diagram of the stacked piezoelectric ceramics;

[0030] Figure 7 This is the working principle diagram of the piezoelectric motor;

[0031] Figure 8 This is the structural diagram of the double-side driven piezoelectric linear motor.

[0032] In the figure: 1-stator, 2-sliding base, 3-preloading mechanism, 4-moving element, 5-base;

[0033] 11-four-bar connecting rod assembly I, 12-four-bar connecting rod assembly II, 13-four-bar connecting rod assembly III, 14-four-bar connecting rod assembly IV;

[0034] a1-four-bar linkage Ⅰ, b1-laminated piezoelectric ceramic Ⅰ, c1-preload spring Ⅰ, d1-adjusting stud Ⅰ, e1-driving foot Ⅰ;

[0035] a2-four-bar linkage II2, b2-laminated piezoelectric ceramic II, c2-preload spring II, d2-adjusting stud II, e2-driving foot II;

[0036] 21- stator connecting block, 22- base body, 23- cross roller guide rail, 24- guide rail fixing block, 25- guide rail adjusting block, 26- adjusting bolt, 31- compression spring, 32- guide piece, 33- differentiator head, 34- differentiator head support. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figure 1-2 As shown, the four-bar direct-push piezoelectric linear motor of the present invention is composed of a stator 1, a sliding base 2, a pre-stressing mechanism 3, a mover 4 and a base 5. The stator 1 is fixedly mounted on the sliding base 2 by bolts. The movement direction of the sliding base 2 is perpendicular to the movement direction of the mover 4, and is mounted on the base 5 through the cross roller guide 23 and the guide fixing block 24 thereon. The pre-stressing mechanism 3 is mounted on the base 5 and connected to the sliding base 2, and the pre-stressing mechanism 3 is transmitted to the stator driving foot Ⅰe1, the stator driving foot Ⅱe2 and the contact surface of the mover through the sliding base 2, so as to provide an adjustable pre-stressing force for the piezoelectric linear motor.

[0039] The stator 1 includes a four-bar connecting assembly I11 and a four-bar connecting assembly II12. Figure 3(a)-Figure 3(c) As shown, the four-bar linkage assembly Ⅰ11 and the four-bar linkage assembly Ⅱ12 are both composed of a four-bar linkage, a laminated piezoelectric ceramic, a preload spring, an adjustment stud, and a driving foot.

[0040] Specifically, the four-bar linkage assembly Ⅰ11 includes a four-bar linkage Ⅰa1, a laminated piezoelectric ceramic Ⅰb1, a pre-tension spring Ⅰc1, an adjustment stud Ⅰd1, and a driving foot Ⅰe1. The four-bar linkage ⅠaⅠ is connected to each other by a flexible hinge. The laminated piezoelectric ceramic Ⅰb1 is installed in the four-bar linkage ⅠaⅠ, and the pre-tension spring ⅠcⅠ is also installed in the four-bar linkage ⅠaⅠ. The four-bar linkage ⅠaⅠ is tightened by the pre-tension spring ⅠcⅠ, so as to realize the pre-tightening of the laminated piezoelectric ceramic Ⅰb1. One end of the adjustment stud ⅠdⅠ hooks the pre-tightening spring, and the other end cooperates with the nut on the four-bar linkage ⅠaⅠ and extends out of the four-bar linkage ⅠaⅠ. The pre-tightening force is adjusted by adjusting the length of the locking thread on the adjustment stud ⅠdⅠ. The driving foot Ⅰe1 is connected to the four-bar linkage ⅠaⅠ and is located on the opposite side of the adjustment stud ⅠdⅠ.

[0041] Specifically, the four-bar linkage assembly II12 includes a four-bar linkage IIa2, a laminated piezoelectric ceramic IIb2, a pre-tightening spring IIc2, an adjusting stud IId2, and a driving foot IIe2. The four bars inside the four-bar linkage IIa2 are mutually connected by flexible hinges. The laminated piezoelectric ceramic IIb2 is installed in the four-bar linkage IIa2, and the pre-tightening spring IIc2 is also installed in the four-bar linkage IIa2. The four-bar linkage IIa2 is tightened by the pre-tightening spring IIc2 to achieve the pre-tightening of the laminated piezoelectric ceramic IIb2. One end of the adjusting stud IId2 hooks the pre-tightening spring, and the other end of the adjusting stud IId2 cooperates with the nut on the four-bar linkage IIa2 and extends out of the four-bar linkage IIa2. The pre-tightening force is adjusted by adjusting the length of the thread on the adjusting stud IId2. The driving foot IIe2 is connected to the four-bar linkage IIa2 and is located on the opposite side of the adjusting stud IId2.

[0042] The adjusting studs (Id1, IId2) are provided with triangular bevels. The driving feet Ie1 and IIe2 are provided with chip removal grooves, as shown in FIG3(b), to prevent the waste chips generated by the motor wear from adhering to the contact surface.

[0043] The laminated piezoelectric ceramics (Ib1, IIb2) push the four-bar flexible mechanism (Ia1, IIa2) in the vertical direction, and the horizontal component of the parasitic motion generated by the four-bar flexible mechanism pushes the mover 4 to move. When an electrical signal with a phase difference of 90° is applied to the two groups of laminated piezoelectric ceramics (b1, b2), the two stator driving feet Ie1 and stator driving feet IIe2 of the stator will produce alternating motion.

[0044] like Figure 4 As shown, the sliding base 2 is composed of two stator connection blocks 21, a base body 22, two sets of cross roller guide rails 23, two guide rail fixing blocks 24, two guide rail adjustment blocks 25 and two adjustment bolts 26. The sliding base 2 is an axisymmetric structure. The stator connection block 21 is installed on the base body 22. The four-link assembly I11 and the four-link assembly II12 of the stator 1 are respectively installed on the left and right stator connection blocks 21 by bolts. The stator connection block 21 raises the stator 1 to avoid contact and friction between the stator 1 and the base body 22. On the left side of the sliding base 2, one of the cross roller guide rails 23 is installed and fixed on the base body 22, and the other is installed on the guide rail fixing block 24, so that the sliding base 2 can only slide relative to the bottom plate 5 along the vertical direction of the movement of the mover 4. The guide rail adjustment block 25 and the adjustment bolt 26 are installed on one side of the guide rail fixing block 24, and the parallelism of the cross roller guide rail 23 is adjusted by rotating the thread length of the adjustment bolt 26. The guide rail fixing block 24 and the guide rail adjustment block are both installed on the base 5. The right side of the sliding base 2 has the same structure as the left side.

[0045] like Figure 5As shown, the preload mechanism 3 is composed of a compression spring 31, a guide member 32, a differential head 33, and a differential head support 34. The compression spring 31 is mounted on the guide member 32, and the guide member 32 is connected to the differential head support 34 through the differential head 33. The guide member 32 can limit the swing of the compression spring, and the preload can be adjusted by adjusting the elongation of the differential head 33. The differential head support 34 is fixed to the base 5 by bolts.

[0046] like Figure 6 As shown in the figure, it is the electrical signal diagram applied by the motor to two groups of stacked piezoelectric ceramics during one working cycle:

[0047] In the 0-T / 4 period, a square wave signal is applied to the laminated piezoelectric ceramic Ⅰb1, and the four-bar linkage assembly Ⅰ11 amplifies the output displacement of the laminated piezoelectric ceramic Ⅰb1, driving foot Ⅰe1 pushes the mover 4 to slide one step to the left, and there is no voltage on the laminated piezoelectric ceramic Ⅱb2, and the four-bar linkage assembly Ⅱ12 does not move;

[0048] In the T / 4-T / 2 period, the voltage applied to the laminated piezoelectric ceramic Ⅱb1 remains unchanged, the four-bar linkage assembly Ⅰ11 maintains its original position, the square wave signal is applied to the laminated piezoelectric ceramic Ⅱb2, the four-bar linkage assembly Ⅱ12 amplifies the output displacement of the laminated piezoelectric ceramic Ⅱb2, and the driving foot Ⅱe2 contacts the mover;

[0049] During the T / 2-3T / 4 period, the voltage applied to the laminated piezoelectric ceramic Ⅰb1 becomes zero, the four-bar linkage Ⅰ11 shrinks and returns to its initial position, the driving foot Ⅰe1 does not contact the mover, the voltage applied to the laminated piezoelectric ceramic Ⅱb2 remains unchanged, the four-bar linkage Ⅱ12 remains in place, and the driving foot Ⅱe2 is still in contact with the mover;

[0050] In the 3T / 4-T period, the voltage applied to the laminated piezoelectric ceramic Ⅰb1 is still zero, and the voltage applied to the laminated piezoelectric ceramic Ⅱb2 becomes zero, and the four-bar linkage assembly Ⅱ12 contracts and returns to its initial position. During the contraction process, the pre-stressing mechanism 3 presses the driving foot Ⅱe2 on the mover 4, and the driving foot Ⅱe2 moves the mover 4 one step to the left.

[0051] like Figure 7 As shown in the figure, it is the working principle diagram of the motor in one cycle. In the 0-T / 4 cycle, the stator 1 moves one step to the left, and the mover 2 moves Δ to the left. In the T / 4-T / 2 cycle and the T / 2-3T / 4 cycle, the stator 1 stores the step, and the mover 4 does not move. In the 3T / 4-T cycle, the stator 1 releases the stored step and pushes the mover 4 to move Δ to the left again. In the whole working cycle, the mover 4 moves 2Δ to the left.

[0052] In order to further improve the performance of the four-bar direct-push piezoelectric linear motor proposed in the present invention, the present invention also proposes a double-side driven piezoelectric linear motor composed of four four-bar assemblies, such as Figure 8The double-side driven piezoelectric linear motor is composed of four four-link assemblies Ⅰ11, four-link assemblies Ⅱ12, four-link assemblies Ⅲ13, four-link assemblies Ⅳ14, two sliding bases 2, two pre-loading mechanisms 3, a mover 4 and a base 5.

[0053] The left side of the mover 4 is connected to the four-link assembly III 13 and the four-link assembly IV 14 of the stator II (pressed against each other), the stator II is installed on the left sliding base, the left pre-pressing mechanism 3 is connected to the left sliding base (pressed against each other), the right side of the mover is connected to the four-link assembly I 11 and the four-link assembly II 12 of the stator I (pressed against each other), the stator I is installed on the right sliding base, and the right sliding base is connected to the right pre-pressing mechanism 3 (pressed against each other). The mover 4, the stator (I, II), the two sliding bases 2, and the pre-pressing mechanism 3 are all installed on the base 5.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Four-link direct-push piezoelectric linear motor, characterized by , consisting of a stator, a sliding base, a pre-stressing mechanism, a mover and a base, wherein the stator is fixedly mounted on the sliding base by bolts, the movement direction of the sliding base is perpendicular to the movement direction of the mover, the sliding base is mounted on the base through the cross roller guide rail and the guide rail fixing block thereon, the stator contacts the side of the mover through its driving foot, the pre-stressing mechanism is mounted on the base and connected to the sliding base, and the pre-stressing force is transmitted to the contact surface of the stator driving foot and the mover through the sliding base, so as to provide pre-stressing force for the piezoelectric linear motor; The stator includes a four-bar linkage assembly, which is composed of a four-bar linkage, a laminated piezoelectric ceramic, a preload spring, an adjustment stud, and a driving foot; The four links inside the four-bar linkage are mutually connected by flexible hinges, the laminated piezoelectric ceramic is installed in the four-bar linkage, the preload spring is also installed in the four-bar linkage, one end of the adjusting stud is hooked to pull the preload spring, and the other end cooperates with the nut on the four-bar linkage and extends out of the four-bar linkage, and the preload force is adjusted by adjusting the length of the locking thread on the adjusting stud, and the driving foot is connected to the four-bar linkage and is located above the laminated piezoelectric ceramic; The sliding base is composed of two stator connection blocks, a base body, two sets of cross roller guides, two guide fixing blocks, two guide adjusting blocks and two adjusting bolts; The sliding base is an axisymmetric structure. The stator connection block is installed on the base body. The left part of the sliding base: One of the cross roller guide rails is fixed on the base body, and the other is installed on the guide rail fixing block, so that the sliding base can only slide relative to the bottom plate in the vertical direction of the mover movement; The guide rail adjustment block and the adjustment bolt are installed on one side of the guide rail fixing block, and the parallelism of the cross roller guide rail is adjusted by rotating the thread length of the adjustment bolt to lock it; The guide rail fixing block and guide rail adjusting block are both installed on the base, and the structure of the right side of the sliding base is the same as that of the left side; The preload mechanism is composed of a compression spring, a guide, a differential head, and a differential head support. The compression spring is installed on the guide. The guide is connected to the differential head support through the differential head. The guide limits the swing of the compression spring. The preload is adjusted by adjusting the elongation of the differential head. The differential head support is fixed to the base by bolts. The stator is composed of a four-link assembly I and a four-link assembly II, wherein the four-link assembly I includes an adjusting stud I and a driving foot I, and the four-link assembly II includes an adjusting stud II and a driving foot II, and the four-link assembly I and the four-link assembly II of the stator are respectively mounted on the left and right stator connecting blocks thereof by bolts; When electrical signals with a phase difference of 90° are applied to two groups of laminated piezoelectric ceramics, the two stator driving feet I and stator driving feet II of the stator will produce alternating motions.

2. The four-bar direct-push piezoelectric linear motor according to claim 1, characterized in that: The adjusting stud has a triangular bevel and the driving foot has a chip removal groove.

3. The four-bar direct-push piezoelectric linear motor according to claim 1, characterized in that: The stator is composed of a four-link assembly I, a four-link assembly II, a four-link assembly III, and a four-link assembly IV, two sliding bases, and two preloading mechanisms; The left side of the mover is connected to the four-link assembly III and the four-link assembly IV of the stator II, the stator II is installed on the left sliding base, the left preloading mechanism is connected to the left sliding base, the right side of the mover is connected to the four-link assembly I and the four-link assembly II of the stator I, the stator I is installed on the right sliding base, and the right sliding base is connected to the right preloading mechanism; When electrical signals with a phase difference of 90° are applied to two groups of laminated piezoelectric ceramics, the four stator driving feet I and III and the four stator driving feet II and IV of the stator will be alternately actuated.

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