JPH01120473A - Motion converting mechanism - Google Patents

Abstract

PURPOSE:To reduce stress in a leaf spring and to improve durability by increasing cross-section areas at respective securing end sections while decreasing cross-section area at an intermediate resiliently deformed section in the cross-section area in the direction crossing perpendicularly with displacing direction of two leaf springs. CONSTITUTION:Both leaf springs 8, 9 are extended from respective fixing faces 6, 7 in expanding/shrinking direction of a piezoelectric element 2. The second leaf spring 9 is displaced approximately in parallel with the first spring 8 to incline an inclinable member 10. In the cross-section area in the direction crossing perpendicularly with displacing direction of both leaf springs 8, 9, cross-section areas at end sections 8a, 9a to be secured to a movable chip 5 and the inclinable member 10 are made large while the cross-section areas of the intermediate resiliently deformed sections 8b, 9b are made small. Consequently, stress functioning onto the secured ends of both leaf springs can be reduced, resulting in improvement of durability.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is characterized in that a tilting member is fixed to one end of two leaf springs arranged approximately parallel to each other, and one leaf spring is tilted relative to the other leaf spring. The present invention relates to a motion conversion mechanism in which the tilting member is tilted back and forth by displacing the tilting member substantially in parallel.

(Prior Art) A motion converting mechanism for moving an 1lr1 moving member using two leaf springs is already known in Japanese Patent Application No. 143530/1988 filed by the same applicant.

That is, in this case, as shown in FIGS. 8 and 9, two plates and springs 8 and 9 are fixed at their proximal ends to opposing surfaces of the frame 1 and the mover 5 by brazing, respectively.
A tilting member 10 is fixed to the distal end side by brazing. Then, in response to the displacement h1 of the movable element 5 based on the expansion and contraction of the piezoelectric element 2, the leaf spring 9 on the movable element 5 side is displaced approximately parallel to the leaf spring 8 on the frame 1 side.
By elastically deforming the two leaf springs 8 and 9, the tilting member 10 is tilted.

Further, as shown in FIG. 9, the two leaf springs 8.9 are made of rectangular spring plates having approximately uniform thickness and width from one end to the other end.

(Problems to be Solved by the Invention) In the above-described system, when one leaf spring 9 is displaced approximately parallel to the other leaf spring 8 and both leaf springs 8 and 9 are elastically deformed, The stress of both leaf springs 8, 9 also acts on the fixed end of the brazing part of both leaf springs 8, 9 to the tilting member 10. By repeating the elastic deformation of both leaf springs 8 and 9, both leaf springs 8 and 9 are compressed against the tilting member 10.
Cracks occur at the fixed end of the solder, for example, at the brazed portion near the 0 point in FIG. This causes a problem in that stress is concentrated at the cracked portion and the leaf spring is thereby broken.

Therefore, a technical problem to be solved in the present invention is to improve durability by reducing the stress acting on the fixed ends of both leaf springs with respect to the tilting member.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has a tilting member fixed to one end of two leaf springs arranged substantially parallel to each other, so that one leaf spring can be In the motion converting mechanism for tilting the tilting member, which is to be displaced approximately parallel to the leaf spring, the cross-sectional area in the direction approximately perpendicular to the displacement direction iri in the portion of the leaf spring excluding the fixed end is , the structure is such that a portion is provided that is smaller in cross-sectional area than the fixed end.

(Function) According to the above configuration, when one root spring is displaced approximately parallel to the other leaf spring and both leaf springs are elastically deformed, the stress of both leaf springs is It mainly acts on the part with a smaller cross-sectional area than the fixed end of the leaf spring,
The stress acting on the fixed ends of both leaf springs is reduced.

(Example 1) Example 1 of the present invention will be described below with reference to FIGS. 1 to 4. Embodiment 1 exemplifies a print head that is used in the print head. In FIG. It is made of approximately parallel vertically rectangular metal plates with a predetermined thickness. A support portion 4 that supports one end (lower end) of the piezoelectric element 2 via a temperature compensating material 3 is provided at the lower end of one side of the frame 1 so as to protrude laterally.

The piezoelectric element 2 is made of laminated piezoelectric ceramic, and expands and contracts in the lamination direction (up and down direction) by applying a voltage. A temperature compensating material 3 is fixed to one end surface of the piezoelectric element 2 with an adhesive or the like. The piezoelectric element 2 is supported by the support surface 4a-4 of the support portion 4 in its temperature compensation material 3. Note that the temperature compensating material 3
This corrects contraction of the piezoelectric element 2 due to changes in ambient temperature by elongation, and maintains the top surface height of the piezoelectric element 2 at a constant height.

A rectangular movable element 5 is provided on the other end surface (upper end surface) of the piezoelectric element 2.
is fixed with adhesive or the like. This mover 5 is
The negative side faces the one side of the frame 1, □, with a predetermined gap therebetween. On the facing surfaces of the frame 1 and the movable element 5, a pair of first. Spring mounting surfaces 6.7 for fixing the second leaf springs 8.9 are each formed as a flat surface parallel to the direction of expansion and contraction of the piezoelectric element 2.

A first leaf spring 8 is fixed to the spring mounting surface 6 of the frame 1 by brazing or the like with one side of the first leaf spring 8 in contact with the surface.

A second root spring 9 is attached to the spring mounting surface 7 of the movable element 5.
The second leaf spring 9 is movably superposed with the first root spring 8 and its opposing surface in a state in which they are in contact with each other. There is.

Said 1st. Both second leaf springs 8, 9 have their respective mounting surfaces 6.
7 extends by a predetermined length in the direction of expansion and contraction of the piezoelectric element 2. 1st. A tilting member 10 is fixed to the tips of the second leaf springs 8°9, and the second leaf spring 9 is moved relative to the first leaf spring 8 via the movable element 5 based on the expansion and contraction of the piezoelectric element 2. The tilting member 10 is tilted by displacing it approximately in parallel.

Said 1st. In the second double leaf spring 8.9, in the cross-sectional area in the direction orthogonal to the displacement direction, the fixed end portions 8a and 9a have a large cross-sectional area with respect to the frame 1, the mover 5, and the tilting member 10, and the The cross-sectional areas of the elastically deformable portions 8b and 9b are intentionally made small.

In this embodiment 1, as shown in FIGS. 3 and 4, 1.
The second double plate spring 8.9 has a groove 8c in the plate width direction on the side surface opposite to the opposing surface.

9C is recessed, and both leaf springs 8 are connected by the grooves 3c and 9c.
．． Thin elastic deformable portions 8b and 9b are formed on the adjacent sides of the elastic deformable portions 9.

Said 1st. The tilting member 10 fixed to the tips of the second double leaf springs 8.9 has a highly rigid holder 11 at its base,
It is mainly composed of a 4!1ft arm 12 on the distal end side.

The holder 11 has a first groove 13 formed in its lower surface.
．． The tips of the second leaf springs 8 and 9 are fixed to the opposite sides of the opposite surfaces of the leaf springs 8 and 9 by brazing in the upright position.

An arm 12 is installed in a groove 14 recessed in the front side of the holder 11.
The base of is inserted and secured by brazing.

The base end of a printing wire 715 is fixed to the tip of the arm 12 by brazing.

The movable element 5 moves in the direction of expansion and contraction of the piezoelectric element 2 due to the application of voltage.
An elastically deformable connecting member 16 is disposed between the frame 1 and the movable element 5 in order to move the movable member 5 in parallel. As shown in FIG. 2, this connecting member 16 is longitudinally elongated along the stacking direction of the piezoelectric elements 2 on the side opposite to the frame 1, and its lower end is fixed to the end surface of the support part 4 of the frame 1, and its upper end is fixed to the end surface of the movable element 5 on the side opposite to the second leaf spring 9.

Further, the connecting member 16 is made of a plate material that has a plate width in a plane parallel to the plate surface of the frame 1 and is thin in a direction perpendicular thereto. The elastic force of the connecting member 16 is set so that the moving force of the movable element 5 due to the elongation of the piezoelectric element 2 acts almost equally on the second plate spring 9 and the connecting member 16. The movable element 5 is adapted to be moved in parallel in the direction of expansion and contraction of the piezoelectric element 2.

Further, in this embodiment, at the upper end of the connecting member 16,
When the tilting member 10 returns to its tilt 173, its arm 1
A stopper 17 made of low-resilience rubber is disposed for abutting and supporting one side of 2.

Further, in this embodiment, the frame 1 and the connecting member 16 are made of materials having the same coefficient of linear expansion, so that they can cope with temperature changes.

This first embodiment is configured as described above. Therefore, when a voltage is applied between both electrodes of the piezoelectric element 2, the piezoelectric element 2 extends by a predetermined length in the stacking direction, that is, in the direction of the arrow X in FIG.
is moved. Then, receiving the moving force of the mover 5, the second
The root spring 9 is pushed up along the first leaf spring 8 and
The leaf spring 9 is elastically deformed into a curved shape at its thin elastically deformable portion 9b. The curved elastic deformation of the second diagonal spring 9 generates a rotational moment in the direction of arrow P in FIG. 2, whereby the first leaf spring 8 is slightly elastically deformed in its thin elastic deformation portion 8b. At the same time, the tilting member 10 is tilted.

Then, the printing wire 15 at the tip of the tilting member 10 is guided by a predetermined number of guide members 21, and the tip thereof is advanced to the printing position. By tilting the tilting member 10 in this manner, the elongation of the piezoelectric collector 2 is significantly expanded and transmitted to the printing wire 15.

When the application of voltage to the piezoelectric element 2 is cut off, the piezoelectric element 2 is shortened to its original state. Then, the movable element 5, the first .
The second leaf springs 8.9 and the tilting member 10 are returned to their original states, and the printing wire 15 is returned to its original state.

As described above, while the second leaf spring 9 is displaced approximately parallel to the first leaf spring 8 via the mover 5 based on the expansion and contraction of the piezoelectric cord 2, both leaf springs 8 and 9 are elastically displaced. When deforming, the thin elastic deformation portion 8 of each leaf spring 8, 9
Most of the stress acts on b, 9b, and each leaf spring 8.9
The stress acting on the fixed ends 8a, 9a due to the brazing of the upper and lower parts can be extremely small. Therefore, due to repeated elastic deformation of both the first and second leaf springs 8.9, cracks can be prevented from occurring in the brazed portions of the fixed ends 8a and 9a, thereby improving durability. be able to.

By CΔEDS (structural analysis) calculation, the first . As shown in FIGS. 8 and 9, the stress acting on the 0 point, P point, and Q point of each part of the second leaf spring 8°9 and the leaf spring with uniform plate width and plate thickness (this invention The stress acting on the 0 point, P point, and Q point of each part of 8°9 was determined as shown in Table 1 below.

Table 1 In addition, leaf springs 8.9 and 9 were used as shown in Table 2 below.

Therefore, as is clear from Table 1, this Example 1
Now, the stress acting on the fixed end 0 point of the leaf springs 8 and 9 is expressed as 7.
The stress at the fixed end 0 point can be reduced to 6 to 9/s 2, and the stress at the fixed end 0 point can be halved compared to the prior art where the fixed end 0 point is 14.4'i/m2. Ta.

(Example 2) Next, Example 2 of the present invention will be described with reference to FIG. In this second embodiment, the first. Second double leaf spring 8.
9 has three grooves 8c each on its opposing surface and the opposite side.
, 8d, 8e, 9c, 9d.

9e are recessed in the width direction of the leaf spring at predetermined intervals in the direction of displacement of the leaf spring. Of these three grooves, the grooves 8c and 9c in the center are grooves 8d and 8 (3, 9d,
Compared to 9e, the groove depth is appropriately deep. Then, the stress of each position spring 8.9 is adjusted to
The effect is not concentrated on the thin wall portion formed by d, but is distributed to the thin wall portions formed by the grooves 8d, 8e, 9d, and 9e on both sides. The other parts are almost the same as in the first embodiment.

(Example 3) Next, Example 3 of the present invention will be described with reference to FIG. In this third embodiment, the first. Second double leaf spring 8.
9 has two grooves 8c each on its opposing surface and the opposite side.
, 8d, 9c, and 9d are recessed in the plate width direction at predetermined intervals in the displacement direction of the plate spring. Each of these two grooves 8
C, 8d, 9c, and 9d are formed to have the same groove width and groove depth, and the stress of each leaf spring 8, 9 is transferred to each of the two grooves 3c.
.

It is configured so that it is applied to each thin portion of 8d, 9c, and 9d in a substantially uniformly distributed manner.

The other parts are almost the same as in the first embodiment.

(Embodiment 4) Next, Embodiment 4 of the present invention will be described according to FIG. 7. In this fourth embodiment, the first. Second double leaf spring 8.
The plate width of the elastically deformable portions 8t) and 9b of 9 is formed to be smaller than the plate width of the rigid rJ end portions 3a and 9a. Furthermore, in this embodiment, the fixed ends Qa of the leaf springs 8 and 9,
Notches 8f and 9f are formed in 9a. On the other hand, in the spring mounting surface 6 of the frame 1, the spring mounting surface 7 of the flexible fJ+ element 5, and the groove 14 of the holder 11 at the base of the tilting member 7,
Fitting portions 6a, 7a that fit into the cutouts 8f, 9f,
14a is formed. Then, the fixed ends 8a, 9a of each leaf spring 8.9 have eight notches, 9f, and each fitting portion 6a.
, 7a, and 14a due to the positioning action by fitting.
With the fixed ends 8a, 9a of each leaf spring 8, 9 positioned, the fixed ends 8a, 9a of each leaf spring 8.9 are connected to the spring mounting surface 6 of the frame 1, the movable element 5, Spring mounting surface 7
and is fixed to the groove 13 of the holder 11 by brazing. The other parts are almost the same as in the first embodiment.

(Effects of the Invention) As described above, according to the present invention, both leaf springs act when one leaf spring is displaced approximately parallel to the other leaf spring and both leaf springs are elastically deformed. The stress of
The stress acting on the tilting member is mainly applied to a portion having a smaller cross-sectional area than the fixed ends of both leaf springs, thereby reducing the stress acting on the fixed ends of both leaf springs. Therefore, even if one fixed end of both leaf springs is fixed to the tilting member by brazing, the brazing of the fixed end can prevent cracks from occurring in the part and improve durability. There is an effect.

[Brief explanation of the drawing]

Embodiment 1 of the present invention is shown in FIGS. 1 to 4, in which FIG. 1 is a perspective view showing the main parts of the print head, FIG. 2 is a side view, and FIG. A perspective view showing a second double leaf spring;
FIG. 4 is a side view showing the main parts of the motion conversion mechanism, FIG. 5 is a side view showing the main parts of the second embodiment of the invention, and FIG. 6 is a side view showing the main parts of the third embodiment of the invention. , FIG. 7 is an exploded perspective view showing the main parts of Embodiment 4 of the present invention. Figures 8 and 9 show the prior art;
The figure is a side view, and FIG. 9 is a perspective view of the leaf spring. 1... Frame 2... Piezoelectric element 5... Mover 8... First plate spring 8b... Elastic deformation portion 8C... Groove 9... Second plate spring 9b... Elasticity Deformed portion 9C... Full 10... Tilting member applicant Brother Industries, Ltd. Agent Patent attorney Hidehiko Okada (1 other person) 1... Frame 2... Piezoelectric element Figure 1 Figure 2 -

Claims (4)

[Claims] (1) A tilting member is fixed to one end of two leaf springs arranged approximately parallel to each other, and movement of tilting the tilting member by displacing one leaf spring approximately parallel to the other leaf spring. A motion conversion mechanism characterized in that a portion of the leaf spring other than the fixed end is provided with a cross-sectional area in a direction substantially orthogonal to the displacement direction that is smaller than the cross-sectional area of the fixed end. . (2) The motion conversion mechanism according to claim 1, wherein the two leaf springs have grooves cut from side surfaces opposite to each other, and thin-walled portions on sides adjacent to each other. (3) The leaf spring has a plurality of grooves cut from the side surface in the displacement direction.
The motion conversion mechanism described in Section. (4) The leaf spring has a width smaller in a direction substantially perpendicular to the displacement direction and substantially parallel to the other leaf spring than the width near the fixed end. The described motion conversion mechanism.