JPH0519470B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a mechanical amplification mechanism that amplifies and drives the motion of an electrical or mechanical transducer, and more specifically relates to a mechanical amplification mechanism that amplifies and drives the motion of an electrical or mechanical transducer. The present invention relates to mechanical amplification mechanisms mainly applied to printing devices such as printers or switches such as relays.

(Prior Art and its Problems) Conventionally, drive devices using electromechanical transducers include printing devices such as print heads of printers, and switches such as relays and switches. For example, most dot impact printer print heads use electromagnets or permanent magnets as their driving source. However, this system has the drawback of requiring a large amount of input energy compared to the required energy due to copper loss and iron loss during driving, and low energy conversion efficiency. For this reason, recently electrostrictive elements,
Alternatively, a mechanism is being considered that uses a piezoelectric element as a drive source to reduce power consumption and heat generation and enable high-speed operation. However, in this method, the elongation during excitation of the electrostrictive or piezoelectric element is 0.005 to 0.01 mm.
Because it is so small, it is 0.3 mm to 0.5 mm, which is required for the output end effecting element of a normal printer print head or relay mechanism.
A displacement amplification means is required to obtain a displacement of .
In order to meet this requirement, there is a mechanism as shown in FIG. 7 and described in Japanese Patent Application Laid-Open No. 113625/1983 as a mechanism that has been proposed in the past. In FIG. 7, a curved spring 26 is curved upward (in the printing direction) by an adjustment screw 25.
is fixed at both ends to a holding element 27 , and one of the holding elements 27 is seated on a piezoelectric crystal device 28 and the other on a fixed holding part 29 . In this structure, the bending spring 26 is bent by the excitation of the piezoelectric crystal device 28, and the printing needle 3 provided at the center of the bending spring 26 is bent.
It is driving 0. In this method, when displacement is applied in the axial direction of the curved spring 26, a large amount of deflection can be obtained at the center of the curved spring 26, as is clear from the well-known buckling theory, and the structure is also simple. However, in a mechanism using such a buckling spring, the amount of displacement of the piezoelectric crystal 28 is ε, and the length of the curved spring 26 is l.
Then, the amount of deflection S at the center of the curved spring 26 is geometrically approximated by S=2√/π, but since the displacement transmission is lost due to the deformation of the fixed holding part 29, a long curved spring is used to compensate for the loss. 26 is required. For example, when ε = 0.01 mm, unless l = 100 mm, the normally required deflection amount S = 0.4 mm cannot be achieved. Furthermore, since the electrocrystal device 28 is directly connected to the curved spring 26, the entire mechanism becomes large when combined with the length of the curved spring 26, which has the drawback of making it difficult to miniaturize printer print heads, relays, etc. It was hot. There is an amplification mechanism disclosed in Japanese Patent Application No. 58-049248 shown in FIG. 8 that eliminates these drawbacks and has a small size and a high amplification factor. In FIG. 8, it is composed of two lever arms 32 as displacement amplifying means connected to both ends of an electrostrictive or piezoelectric element 31 in the direction of expansion and contraction, and a beam 33 supported so as to be sandwiched between the ends of each of the lever arms 32. ing. In this structure, an expanded displacement is applied in the axial direction of the beam 33 from each lever arm 32 by the excitation of the electrostrictive or piezoelectric element 31, and further, due to the deformation of the beam 33, an expanded displacement is applied to the printing needle 34 at the center of the beam 33. occurs. In such a system, a compact mechanism can be obtained because the displacement amplification factor is large even if the length of the quantity is short. however,
In this structure, since a movable body such as the lever arm 32 is disposed outside the substrate 35 serving as a fixed portion, it is difficult to position the printing needle 34 as an output end and the substrate 35. That is, a printer is usually constructed from a plurality of heads, and for this purpose, it is necessary to arrange the printing needles of each head within about 0.05 mm. This structure has the disadvantage that positioning adjustment is difficult and manufacturing costs are high.

(Object of the Invention) The present invention eliminates such conventional drawbacks and provides a mechanical amplification mechanism that is small, has a large amplification factor, and is low in cost.

(Structure of the Invention) According to the present invention, in an amplification mechanism that amplifies and drives the motion of an electrostrictive or piezoelectric element, a base that fixes and supports one end of the electrostrictive or piezoelectric element in the expansion/contraction direction; It consists of a lever arm as a displacement amplifying means connected to the other end of the element and the base, and a beam as a displacement amplifying means supported between the lever arm and the base, and a beam as an output end is connected to the beam. A mechanical amplification mechanism is obtained, which is characterized in that it is provided with an active element.

(Detailed Description of Configuration) The present invention has solved the conventional problems by adopting the above-mentioned configuration. First, a lever arm is connected to a base that fixes and supports one end of the electrostrictive or piezoelectric element in the expansion and contraction direction through a displacement transmission means that transmits displacement and serves as a fulcrum. Further, the other end of the electrostrictive or piezoelectric element in the expansion/contraction direction is connected to the lever arm via another displacement transmission means. There is also a beam supported between the other end of the lever arm and the other end of the base, and the beam is positioned and connected to the base. Therefore, by excitation of the electrostrictive or piezoelectric element, the lever arm rotates according to this principle using the displacement transmitting means connected to the base as a fulcrum, and the displacement is amplified at the connection part with the beam at the other end of the lever arm. Then, displacement is transmitted from the lever arm in the axial direction of one end of the beam, and the amount of deformation is further amplified as is clear from buckling theory. At this time, the operating element as the output end at the center of the beam obtains amplification displacement at a more accurate position than the base.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing a printer print head according to an embodiment of the present invention. Further, FIG. 2 is a diagram for explaining the operation of FIG. 1. Figure 1,
In FIG. 2, one end of the electrostrictive or piezoelectric element 1 in the direction of expansion and contraction is attached to a base 2, and a lever arm 4 is provided at the other end via means 3 for transmitting the expansion and contraction movement of the electrostrictive or piezoelectric element 1. Furthermore, the lever arm 4 and the base 2 are connected to the other transmission means 3.
Connected with On the other hand, a beam 5 is connected to the tip of the lever arm 4, and the other end of the beam 5 is positioned and fixed to the base 2. This positioning can be achieved, for example, by providing a groove in the base 2 and inserting the beam 5, or by providing other positioning pins.
In addition, a printing needle 6 as an output end is provided at the center of the beam 5, and an adjustment screw 7 that serves as an initial displacement of the beam 5 from the base 2 and a backstop is provided at the rear thereof.
has been established. These base 2, displacement transmitting means 3, lever arm 4, and beam 5 can be made of a metal material such as spring steel or a composite material such as carbon fiber, as long as it has spring properties, and can be manufactured by press punching method, etching method, Mass production is also possible as it can be manufactured using the wire cutting method and injection molding process. The beam 5 and the lever arm 4 may be joined by rotational support such as a pin joint, or fixed support such as welding, and the transmission means 3 may be a branch such as a pin joint made of ceramic with low wear. The driving source is an electrostrictive or piezoelectric element 1, which is made by laminating a plurality of flat plate-like materials with a longitudinal effect, such as lead zirconate titanate (PZT).
A common electrode is provided for each piezoelectric element so that the piezoelectric elements are placed in parallel. In addition, the present invention can be applied to a single electrostrictive or piezoelectric element having a transverse effect or a longitudinal effect. In the above mechanism, elongation 8 is caused by applying a voltage to the electrostrictive or piezoelectric element 1,
This displacement is transmitted to the lever arm 4, amplified, and transmitted in the axial direction of one end of the beam 5. At this time, since the other end of the beam 5 is inserted into a groove in the base 2 and fixed by welding, the printing needle 6 is pushed forward at a more accurate position than the base 2, and the paper 10 and ink ribbon 11 on the platen 9 are pushed out. Impact and dot printing. Thereafter, by stopping the applied voltage, the electrostrictive or piezoelectric element 1 returns to its original length, and at the same time, the lever arm 4 and beam 5 also return to their original positions. To give a specific example of the above embodiment, in a mechanism in which the displacement of the electrostrictive or piezoelectric element 1 is 0.01 mm, the amplification factor of the lever arm 4 is 6 times, and the length of the beam 5 is 40 mm, the printing needle 6 With this method, a displacement of 0.5 mm was obtained, resulting in a small, large displacement, and low-cost print head.

The above amplification mechanisms can be used in a dot impact type line printer by arranging a plurality of them in parallel.
FIG. 3 shows an example of this. In Figure 3,
Each print head is arranged in parallel with a spacer 12 in between and is fixed to a housing 14 with a ribbon guide 13 disposed in front. Also, the housing 14
is provided on the swing mechanism base 15. According to the present invention, there is obtained a printing mechanism for a dot impact type line printer which performs printing by horizontally swinging the printing mechanism consisting of a plurality of such units by the printing pitch.
Further, FIG. 4 shows an example in which each amplification mechanism is integrated. In FIG. 4, a base 16 and a lever arm 17 are integrated for a plurality of amplifying mechanisms, and such a structure can be manufactured by cutting or wire cutting. Even in such a system, the effects of the present invention can be obtained.

Furthermore, the present invention can also be applied to wire dot type printer heads. FIG. 5 shows another embodiment. In FIG. 5, a lever arm 19 and a beam 5 are positioned on a cylindrical base 18, and a wire 20 is provided on the beam 5. Further, the wire 20 is arranged at its tip by a wire guide 21.
Similar performance can be obtained with such a printing mechanism.

The amplification mechanism of the present invention can also be applied to switches such as relays, and one embodiment is shown in FIG. 6. In FIG. 6, a movable contact 22 as an operating element is provided on the beam 5 of the amplification mechanism of the present invention, and a fixed contact 23 is provided on the base 2 corresponding to the movable contact 22.
There are 24. Therefore, during driving, the movable contact 22 moves from one fixed contact 23 to the other fixed contact 24 to perform a relay operation due to electrostriction or expansion and contraction of the piezoelectric element 1. The present invention is also effective in such relays, and provides a relay with large contact displacement, low cost, and high reliability.

(Effects of the Invention) According to the present invention, it is possible to obtain a low-cost mechanical amplification mechanism that is small in size, has a large displacement amplification factor, can position an operating element as an output end, and is easy to assemble.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an embodiment of the present invention, FIG. 2 is a side view for explaining the operation of FIG. 1, and FIG. 3 is a partial perspective view showing an embodiment of the present invention. FIG. 4 is a schematic perspective view showing one embodiment of the present invention, FIG. 5 is a sectional view showing one embodiment of the present invention, FIG. 6 is a perspective view showing another embodiment of the present invention, and FIG. The figure shows a side view of a conventional embodiment, and FIG. 8 shows a perspective view of a conventional embodiment. Each symbol in the figure indicates the following. 1...
Electrostrictive or piezoelectric element, 2...Base, 3...Displacement transmission means, 4...Lever arm, 5...Beam, 6
... Printing needle, 7 ... Adjustment screw, 8 ... Extension of electrostrictive or piezoelectric element, 9 ... Platen, 10 ... Paper, 11 ... Ink ribbon, 12 ... Spacer,
13...Ribbon guide, 14...Housing, 1
5... Rocking mechanism base, 16... Integral base,
17... integrated lever arm, 18... cylindrical base, 19... lever arm, 20... wire,
21... Wire guide, 22... Movable contact, 2
3, 24...Fixed contact, 25...Adjustment screw, 26
... Curved spring, 27 ... Holding element, 28 ... Piezoelectric crystal device, 29 ... Fixed holding part, 30 ... Printing needle, 31 ... Electrostrictive or piezoelectric element, 32 ... Two lever arms, 33 ... Beam, 34 ... Printing needle, 35 ... Board.

Claims (1)

[Claims] 1. In an amplification mechanism that amplifies and drives the motion of an electrostrictive or piezoelectric element, a base that fixes and supports one end of the electrostrictive or piezoelectric element in the expansion and contraction direction, and the other end of the electrostrictive or piezoelectric element is connected to the base. It is composed of a lever arm as a displacement amplifying means, and a beam as a displacement amplifying means supported so as to be sandwiched between the lever arm and a base, and the beam is provided with an operating element as an output end. mechanical amplification mechanism.