JPH02261944A - Wave motion gearing device - Google Patents

Abstract

PURPOSE:To mesh a flexible gear with a rigid circular gear while the flexible one is good deflected into an ellipse, by amplifying a displacement generated by a displacement generating means consisting of a plurality of piezo elements and driving means, and changing if necessary the displacing direction with a displace direction changing means. CONSTITUTION:When in a wave motion gearing device 1, a plurality of piezo elements 21 displaced one after another in the axial direction of a flex spline 3, the displacement generated are amplified first by a displacement amplifying mechanism 32a and then another 32b, and the output is transmitted to the flex spline 3 through a part 33 in contact with the rear of each tooth face of spline 3. Now the flex spline 3 deflects acircularly (elliptically), and the meshing position with a circular spline 2 in different number of cogs will shift gradually, and it is taken out in the form of rotation from an output shaft 5. If necessary, the direction of displacement is changed by a displace direction changing means. Thus displacements of the piezo elements are amplified, and flexible gear is deflected into a sufficient ellipse to ensure the that the torque is transmitted to rigid circular gear certainly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wave gear device, and particularly to an improvement of a wave generator using a piezoelectric element among wave generators used in a wave gear device.

[Conventional technology]

A typical strain wave gear device consists of a rigid circular internal gear, and the teeth of the internal gear are deformed into a non-circular shape (often elliptical) so as to mesh with the internal gear at three points. A flexible external gear having a number of teeth 2n (n is a positive integer) less than the number of teeth, and a wave generator that fits inside the flexible external gear and deflects the flexible external gear in a non-circular manner. It consists of For example, when a rigid circular internal gear is fixed and a manual shaft connected to a wave generator is rotated, the wave generator is rotated, and the flexible external gear, which is elastically deformed into an elliptical shape, and the rigid circular internal gear are combined. The meshing position moves sequentially. When the wave generator rotates once,
The flexible external gear moves in the opposite direction to the rotational direction of the wave generator by an amount 2n fewer teeth than the rigid circular internal gear, and this movement is output from the output shaft connected to the flexible external gear. It can be taken out.

Note that the same effect as described above can be obtained even if the rigid circular gear is formed as an external gear and the flexible gear is formed as an internal gear.

Wave generators that consist of an elliptical plate and a flexible bearing fitted around the outer periphery of the plate have often been used, but because the inertial mass is large and the response characteristics are poor, the applicant filed a patent application in 1982-31 for a wave generator that improved this point.
I was admitted to room number 6999. A wave gear device equipped with this wave generator is shown in FIGS. 13 and 14. The wave gear device 10 includes a rigid circular internal gear 11, a flexible external gear 12 that meshes with the circular internal gear 11, and a wave generator 13 that bends the flexible external gear 12 into an elliptical shape. The disk 15 arranged inside the flexible external gear 12 and the disk 1
The piezoelectric elements 16 are arranged radially on the outer periphery of the piezoelectric element 5 at approximately equal intervals. When a predetermined voltage is applied to the piezoelectric element 16, the piezoelectric element 16 protrudes outward in the radial direction of the disk 150. Therefore, two piezoelectric elements 16 facing each other in the diametrical direction of the disk 15
, for example, the piezoelectric elements A and A2 are connected to the piezoelectric element driving device 1.
7 to force the flexible external gear 12 to
5. It can be bent into an oval shape with A2 as the major axis. Thereafter, the pair of two piezoelectric elements 16 facing each other in the diametrical direction are energized by the piezoelectric element driving device 17, for example, clockwise, in the order of (B,, B2), (C7°C2), (Dl, D2). If you do this, the circular internal gear 11 and the flexible external gear 1
The meshing positions of the circular internal gear 11 and the flexible external gear 12 move sequentially, and relative rotation occurs between the circular internal gear 11 and the flexible external gear 12, which can be taken out as an output from the output shaft 18 connected to the flexible external gear 12. .

[Problem to be solved by the invention]

However, the displacement of the piezoelectric element in this wave generator was small enough to bend the flexible gear into an elliptical shape.

In view of this point, the present invention is capable of amplifying the displacement of the piezoelectric element to sufficiently bend the flexible gear into an elliptical shape, and furthermore, when amplifying the displacement, there is no need to change the direction of the displacement. Therefore, an object of the present invention is to provide a strain wave gearing device that can change the direction of displacement if necessary.

[Means to solve the problem]

In order to achieve this object, the wave generator of the wave gear device according to the present invention includes a displacement generating means, a displacement generating means for amplifying the displacement generated by the displacement generating means, and, if necessary, a displacement generating means. and displacement direction changing means for changing the direction of the displacement generated by the displacement. Among these, the displacement generating means applies the so-called "lever principle."

The displacement generating means includes a plurality of piezoelectric elements arranged radially at approximately equal intervals on the circumference of a circle centered on the axis of the flexspline so that the displacement direction forms a certain angle with the axis of the flexspline; and a piezoelectric element drive device that sequentially selects and energizes piezoelectric elements.

Unless the direction of displacement of the piezoelectric element is perpendicular to the axis of the flexspline, the direction of displacement of the piezoelectric element and the direction in which the flexspline is bent do not match, so the wave gear device is equipped with displacement direction changing means, which will be described later. At least one is provided.

The displacement generating means includes a member having a portion that contacts the piezoelectric element, at least one displacement amplification mechanism, and a portion that contacts the back surface of the tooth surface of the flexspline. The displacement amplification mechanism consists of a member that has a part that receives displacement, a part that acts as a fulcrum, and a part that transmits the amplified displacement, and the distance between the part that acts as a fulcrum and the part that transmits the amplified displacement is equal to the fulcrum. It is longer than the distance between the part that acts as a force and the part that receives displacement.

The displacement direction changing means has two configurations.

One type consists of a member that has two parts extending in two directions from one point and is fixed so that one of the parts acts as a fulcrum. The other consists of an elastic member whose one end is connected to a part of the displacement amplification mechanism that transmits the amplified displacement, and whose other end is fixed, and the direction of the displacement transmitted by the part which transmits the amplified displacement is connected to the other fixed end. It is the direction you are heading. These displacement direction changing means not only change the direction of displacement, but also act to amplify the displacement.

In addition, as a means for simultaneously performing displacement amplification and displacement direction change, an elastic member is provided, one end of which is connected to the piezoelectric element and the other end of which is fixed, and the direction of displacement of the piezoelectric element is controlled by the other fixed end. It is also possible to use a displacement amplification/displacement direction changing means that is directed toward the .

[For production]

According to the above structure of the present invention, the displacement of the piezoelectric element can be amplified and, if necessary, the direction of the displacement can be changed, so that this amplified displacement can sufficiently shape the flexible gear into an elliptical shape. It can be bent to mesh with a rigid circular gear.

〔Example〕

1 to 11 show embodiments of a strain wave gear device according to the present invention. Each of these wave gear devices 1 includes a circular spline 2, a flexspline 3, and a wave generator 4 that bends the flexspline 3 into an elliptical shape and partially meshes with the circular spline 2. The flexspline 3 has a cup-like shape and is connected to the output shaft 5 at its closed end.

[Example I]

FIGS. 1(a) and 1(a) show an embodiment of a wave gear device 1 equipped with a wave generator 4 consisting of a displacement generating means 6 and a displacement generating means 7. As shown in FIG. 4A is a sectional view taken along a plane passing through the axis of the flexspline 3, and FIG. 2B is a sectional view taken along the line xx in FIG. This first
In the wave gear device shown in the figure, the flexspline 3 is an external gear,
The circular spline 2 is in the form of an internal gear.

The displacement generating means 6 includes twelve piezoelectric elements 21 and a piezoelectric element driving device (not shown) that sequentially selects and energizes the piezoelectric elements 21. As shown in FIG. 1(b), the piezoelectric elements 21 are arranged so that their displacement directions are radial at approximately equal intervals around the axis of the flexspline 3 on a plane perpendicular to the axis of the flexspline 3. The flex spline 3 is arranged so that its direction is directed toward the axis of the flex spline 3.

The displacement generating means 7 includes a portion 31 that comes into contact with the piezoelectric element 21;
It consists of a member having two displacement amplification mechanisms 32a and 32b and a portion 33 that comes into contact with the back surface of the tooth surface of the flex spline 3.

Two examples of the displacement amplification mechanism are shown in FIGS. 2(a) and 2(b). The displacement amplification mechanism 32 includes a portion 51 receiving displacement.
, a portion 52 that is fixed at that position with a hinge 70 and acts as a fulcrum, and a portion 53 that transmits the amplified displacement. The distance between the part 52 that acts as a fulcrum and the part 53 that transmits the amplified displacement,
is a portion 52 that acts as a fulcrum and a portion 51 that receives displacement.
The distance between us is longer than that. Therefore, due to the so-called "lever principle", the portion 51 that receives displacement is shown in FIG.
When a displacement X1 is received in the direction shown in (b), from the part 53 that transmits the amplified displacement, the direction of displacement X+ is the same as that shown in (a).
The displacement X2 can be obtained in the opposite direction in (5) of the same figure, and in the same direction in (5) of the same figure. In this case, X2= (L
l/L2) With X, -t', Lt>Lz and the displacement X in Luno is amplified more than the initial displacement X.

The portion 51 receiving displacement receives displacement by being connected to the portion 31 that abuts the piezoelectric element 21 or by being connected to a portion 53 of another displacement amplifier 132 that transmits the amplified displacement. On the other hand, the part 5 that transmits the amplified displacement
3 is connected to a portion 51 that receives displacement of another displacement amplification mechanism 32 to further amplify the displacement, or is integrated with a portion 33 that contacts the back surface of the tooth surface of the flex spline 3 to increase the displacement of the flex spline 3 tooth surface. , and bends the flexspline 3 in a non-circular manner.

The strain wave gear device 1 shown in FIGS. 1(a) and 1(a) having the above configuration operates as follows. When the piezoelectric element 21 is displaced in the axial direction of the flexspline 3, the displacement is amplified by the displacement amplification mechanism 32a, and further amplified again by the displacement amplification mechanism 32b. Displacement amplification mechanism 3
The part that transmits the amplified displacement of 2b is integrated with the part 33 that contacts the back surface of the tooth surface of the flexspline 3, and the amplified displacement is transmitted through the part 33 that contacts the back surface of the tooth surface of the flexspline 3. It is transmitted to flexspline 3. As a result, the flexspline 3 is bent non-circularly, and by sequentially biasing the piezoelectric element 21, for example, clockwise, by the piezoelectric element drive device, the position where the flexspline 3 and the circular spline 2 engage is moved, and the output Output can be taken out from the shaft 5. In addition,
In this case, since the direction of displacement of the piezoelectric element 21 is parallel to the direction in which the flexspline 3 bends, there is no need to change the direction of displacement.

The above embodiment relates to a wave gear device in which the flexspline 3 is an external gear and the circular spline 2 is an internal gear, but a wave gear device in which the flexspline 3 is an internal gear and the circular spline 2 is an external gear is also applicable. It is included within the scope of the present invention.

In FIGS. 3(a) and (b), the flexspline 3 is an internal gear,
The circular spline 2 shows an embodiment of a strain wave gear device in the form of an external gear. FIG. 3A is a sectional view taken along a plane passing through the axis of the flexspline 3, and FIG.

This embodiment has the same structure as the previous embodiment, except that the portion where the energized piezoelectric element 21 contacts the 7-rex spline 3 is the short axis of the ellipse, and operates in the same manner.

[Example ■]

4(a) and 5(a), (b) are equipped with a wave generator 4 consisting of a displacement generating means 6, a displacement generating means 7, and a displacement direction changing means 8. Wave gear device 1
An example is shown below. Figures 4(a) and 5(a) are cross-sectional views taken along a plane passing through the axis of the flexspline 3, and both figures are cross-sectional views taken along line X-X in Figure (a). It is a diagram.

The displacement generating means 6 includes twelve piezoelectric elements 21 and a piezoelectric element driving device (not shown) that sequentially selects and energizes the piezoelectric elements 21. Figure 4(a), et al.) and Figure 5(
As shown in a) and (c), the piezoelectric elements 21 are arranged radially at approximately equal intervals on the circumference of a circle centered on the axis of the flexspline 3 so that the displacement direction is parallel to the axis of the flexspline 3. The displacement direction is toward the closed end of the flexspline 3 in the strain wave gearing device 1 shown in FIG. 4, and in the direction away from the closed end of the flexspline 3 in the strain wave gearing device 1 shown in FIG. It is arranged to face.

The displacement generating means 7 includes a portion 31 that comes into contact with the piezoelectric element 21;
The displacement amplification mechanism 32 is composed of a member having a displacement amplification mechanism 32 and a portion 33 that abuts on the inner surface of the flexspline 3.
The structure of is similar to that shown in FIG.

The displacement direction changing means 8 is a member that has two parts extending in two directions from one point, and is fixed such that one of the parts serves as a fulcrum.

Two examples of the displacement direction changing means 8 are shown in FIGS. 6(a) and 6(a). The displacement direction changing means 8 has two parts 62, 63 extending in two directions at right angles from one point 61,
4 through a hinge 70. Same figure (
In b), point 61 and fixed position 64 coincide. Here, when a horizontal displacement X is applied at point 65 in FIG. 6(a), O)), the portion 63 swings clockwise in the figure with the fixed position 64 as a fulcrum. Along with this, the portion 62 also swings clockwise, and the tip 66 of the portion 62 transmits the displacement X2 in the vertical direction. If the direction of displacement xl is reversed, the direction of displacement X2 is also reversed. In this way, the displacement direction changing means 8 changes the displacement direction. Two parts 62.6
The angle formed by 3 is not limited to a right angle, and any angle may be selected.

The point 65 receiving displacement is connected to the piezoelectric element 21 and receives the displacement of the piezoelectric element 21, or is connected to the portion 53 of the displacement amplification mechanism 32 that transmits the amplified displacement and receives the amplified displacement. The distal end portion 66 that transmits the displacement is connected to the displacement receiving portion 51 of the displacement amplification mechanism 32 and transmits the displacement to the displacement amplification mechanism 32 to further amplify the displacement, or the distal end portion 66 is connected to the displacement receiving portion 51 of the displacement amplification mechanism 32 and transmits the displacement to the displacement amplification mechanism 32 to further amplify the displacement, or It transmits displacement to the flex spline 3 together with the portion 33 that abuts the back surface, thereby bending the flex spline 3 in a non-circular manner.

Further, this displacement direction changing means 8 can also be used as the displacement generating means 7 at the same time. The distance between the fixed position 64 that acts as a fulcrum and the point 66 that transmits displacement is L l ,
If the distance between the fixed position 64 and the point 65 receiving displacement is L2, then when the angle formed by the two parts 62 and 63 is 90 degrees, it can be approximated as X2'i (L, /L,)X. By setting L+>La, the displacement direction changing means 8 can also be used as the displacement generating means 7.

Note that the mounting direction of the hinge 70 is arbitrary;
As shown by the broken line in b), it is most preferable to follow the diagonal line of a rectangle whose two sides are Ll and L2.

The wave gear device 1 having the above configuration operates as follows. In the wave gear device shown in FIG. 4, when the piezoelectric element 21 is displaced toward the closed end of the flexspline 3, the displacement is amplified by the displacement amplification mechanism 32, and the displacement direction is further changed by the displacement direction changing means 8. The displacement is amplified as well. In the wave gear device shown in FIG. 5, when the piezoelectric element 21 is displaced in a direction away from the closed end of the flexspline 3, the displacement direction is changed by the displacement direction changing means 8 and the displacement is amplified. , further amplified by the displacement amplification mechanism 32.

Furthermore, in both FIGS. 4 and 5, the amplified displacement is transmitted to the flexspline 3 via the portion 33 that abuts the back surface of the tooth surface of the flexspline 3. As a result, the flexspline 3 is bent non-circularly, and by sequentially biasing the piezoelectric element 21, for example, clockwise, by the piezoelectric element drive device, the position where the flexspline 3 and the circular spline 2 engage is moved, and the output Output can be taken out from the shaft 5.

The above embodiment is an example of a wave gear device in which the flexspline 3 is an external gear and the circular spline 2 is an internal gear, but as in the case of Embodiment I, the flexspline 3 is an internal gear and the circular spline 2 is an external gear. It is also possible to use a strain wave gearing device in the form of a gear. This type of wave gear device is shown in FIG. 7(a), et al. energized piezoelectric element 2
The structure is the same as that of the previous embodiment except that the portion of the flexspline 3 that the flexspline 1 abuts is the short axis of the ellipse, and the same effect can be obtained.

[Example ■]

FIGS. 8(a) and 8(b) show an embodiment of a wave gear device 1 equipped with a wave generator 4 consisting of a displacement generating means 6, a displacement generating means 7, and a displacement direction changing means 8. . The same figure (a
) is a sectional view taken along a plane passing through the axis of the flexspline 3, and FIG.

The displacement generating means 6 includes twelve piezoelectric elements 21 and a piezoelectric element driving device (not shown) that sequentially selects and energizes the piezoelectric elements 21. As shown in Figure 8(a), et al.
The piezoelectric elements 21 of the displacement generating means 6 are arranged radially at approximately equal intervals on the circumference of a circle centered on the axis of the 7 flex spline 3 so that the displacement direction is parallel to the axis of the 7 flex spline 3. It is arranged so as to face in a direction away from the closed end of 3.

The displacement generating means 7 includes a portion 31 that comes into contact with the piezoelectric element 21;
Four displacement amplification mechanisms 32a, 32b.

32c and 32d, and the structure of the displacement amplification mechanism is the same as that in the strain wave gear device shown in FIG.

The displacement direction changing means 8 includes an elastic member 40 . One end 40a of the elastic member 40 is fixed, and the other end 40b is connected to a portion 53 of the displacement amplification mechanism 32d that transmits the amplified displacement. The direction of the displacement transmitted by the portion 53 transmitting this amplified displacement is the direction of the fixed end 40a. When displacement is transmitted to the one end 40b of the elastic member 40 from the amplified displacement transmitting portion 53 of the displacement amplification mechanism 32d in the direction of the fixed end 40a, that is, in the left direction in the figure, the one end 40a of the elastic member 40 is fixed. Therefore, the elastic member 40 bends in an arc shape so as to be convex in the direction of the circular spline 2 (in the vertical direction in the figure) with both ends 40a and 40b as the end portions. In this way, the displacement generated by the displacement generating means 6 in the horizontal direction in the figure is changed in direction to the vertical direction at the portion where it comes into contact with the back surface of the tooth surface of the flexspline 3.

Note that by increasing the length of the elastic member 40, the amount of deflection at the center of the elastic member 40 can be increased, so the displacement direction changing means 8 provided with this elastic member 40 can also be used as the displacement generating means 7. can do.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced in a direction away from the closed end of the 7-rex spline 3, the displacement is amplified by the four displacement amplification mechanisms 32 a N 32 b 532 c, 32 d. Further, the direction of displacement is changed by the elastic member 40, and the displacement is amplified. The amplified displacement is transmitted to the inner surface of the flexspline 3, and the flexspline 3 is deflected non-circularly. Therefore, by sequentially urging the piezoelectric element 21 clockwise, for example, by the piezoelectric element drive device, the position where the flex spline 3 and the circular spline 2 engage is moved, and an output can be taken out from the output shaft 5.

The above embodiment is a wave gear device in which the flexspline 3 is an external gear and the circular spline 2 is an internal gear, but as in the previous two embodiments, the flexspline 3 is an internal gear and the circular spline 2 is an internal gear. It is also possible to form a strain wave gearing as an external gear.

In addition, as shown in FIG. 8(a), not only is the displacement direction of the piezoelectric element 21 parallel to the axis of the 7-rex spline 3, but also the direction of displacement of the piezoelectric element 21 is parallel to the axis of the 7-rex spline 3. It is also possible to arrange it at an angle with respect to the axis of. In this case, as shown in FIG. 6 (
One or more displacement direction changing means 8 shown in a) or a) are used.

[Example ■]

FIGS. 9(a) and 9(a) show an embodiment of a wave gear device 1 equipped with a wave generator 4 consisting of a displacement generating means 6 and a displacement amplifying/displacement direction changing means 9. FIG. 4(a) is a new view of the flexspline 3 taken along a plane passing through its axis, and FIG.

The displacement generating means 6 has the same structure as the displacement generating means of the wave gear device 1 shown in FIG.

The displacement amplification/displacement direction changing means 9 includes an elastic member 40, one end 40a of which is fixed, and the other end 40a of the elastic member 40 fixed.
b is connected to the piezoelectric element 21 via a suitable connecting member 41, and the direction of displacement of the piezoelectric element 21 is in the direction of the fixed end 40a. In addition, the flex spline 3 of the elastic member 40
The length in the axial direction is sufficiently long for the displacement given by the piezoelectric element 21.

The fixed end 4 is connected from the piezoelectric element 21 to one end 40b of the elastic member 40.
When displacement is transmitted in the direction 0a, that is, in the right direction in the figure, since one end 40a of the elastic member 40 is fixed, the elastic member moves in the direction of the circular spline 2 (in the vertical direction in the figure) with both ends 40a and 40b as ends. ) bends in an arc so that it becomes convex. In this case, since the length of the elastic member 40 is sufficiently long for the displacement given by the piezoelectric element 21, the amount of deflection at the center of the elastic member 40 can be increased. In this way, the displacement generated from the displacement generating means 6 in the horizontal direction in the figure is changed to the vertical direction at the portion where it comes into contact with the inner surface of the flexspline 3, and
Displacement is amplified.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced in the direction away from the closed end of the 7-rex spline 3, the displacement is caused by the elastic member 4.
0 changes the displacement direction and amplifies the displacement. The amplified displacement is transmitted to the inner surface of the flexspline 3, and the flexspline 3 is deflected non-circularly. Therefore, by sequentially urging the piezoelectric element 21 clockwise, for example, by the piezoelectric element drive device, the position where the flex spline 3 and the circular spline 2 engage is moved, and an output can be taken out from the output shaft 5.

In the above embodiment, the flexspline 3 is an external gear and the circular spline 2 is an internal gear. However, as in the case of the front element embodiment, the flexspline 3 is an internal gear and the circular spline 2 is an internal gear. It is also possible to form a strain wave gearing as an external gear.

Furthermore, as shown in FIG. 9(a), not only can the piezoelectric element 21 be arranged so that its displacement direction is parallel to the axis of the flexspline 3, but also that the displacement direction of the piezoelectric element 21 be parallel to the axis of the flexspline 3. It is also possible to arrange it so that it forms a fixed angle with respect to. In this case, piezoelectric element 2
so that the direction of displacement of the sixth
One or more displacement direction changing means 8 shown in Figures (a) and (b) are used.

[Example V]

FIGS. 10(a) and 10(a) show an embodiment of a wave gear device 1 equipped with a wave generator 4 consisting of a displacement generating means 6, a displacement generating means 7, and a displacement direction changing means 8. The same figure (a
) is a sectional view taken along a plane passing through the axis of the flexspline 3, and FIG.

The displacement generating means 6 includes eight piezoelectric elements 21 and a piezoelectric element drive device (not shown) that sequentially selects and energizes the piezoelectric elements 21. As shown in FIG. 10(b), the piezoelectric element 21 of the displacement generating means 6 is arranged in a circle such that the displacement direction is tangential to a circle centered on the axis of the flexspline 3 on a plane perpendicular to the axis. They are arranged at approximately equal intervals around the circumference. The piezoelectric element 21 in this embodiment is of a type that provides displacement in both directions.

The displacement generating means 7 includes a portion 31 that comes into contact with the piezoelectric element 21;
It consists of a member having two displacement amplification mechanisms 32a and 32b. The displacement amplification mechanisms 32a and 32b are shown in FIG. 2(a).
This is similar to the one shown in .

The displacement direction changing means 8 includes an elastic member 40 . Both ends 40a and 40b of the elastic member 40 are displacement amplifying mechanisms 32a.
, 32b, which transmits the amplified displacement. The direction of the displacement transmitted by the portion 53 transmitting this amplified displacement is the direction of the other end. Elastic member 40
Both ends 40a.

When displacement is transmitted to 40b from the amplified displacement transmitting portion 53 of the displacement amplification mechanisms 32a, 32b in the direction toward the other end, the elastic member 40 becomes convex in the direction of the circular spline 2 with both ends 40a, 40b as both ends. It bends in an arc shape. In this way, the displacement generated by the displacement generating means 6 in the horizontal direction in the drawing is converted into a displacement in the vertical direction in the drawing at the portion that comes into contact with the inner surface of the flexspline 3.

Note that the wave generator 4 is provided with a fixing portion 54 between two points 520 that act as fulcrums, and the wave generator 4
is fixed in this fixing portion 54 via a fixing member 55.

The wave gear device 1 having the above configuration operates as follows. When the piezoelectric element 21 is displaced in both tangential directions, the displacement is amplified by the two displacement amplification mechanisms 32a and 32b. Furthermore, the direction of displacement is changed by the elastic member 40. The amplified displacement is flexspline 3
It is transmitted to the inner surface, and the flexspline 3 is deflected in a non-circular manner.

Therefore, by sequentially urging the piezoelectric element 21 clockwise, for example, by the piezoelectric element drive device, the position where the flex spline 3 and the circular spline 2 engage is moved, and an output can be taken out from the output shaft 5.

In the above embodiments, the flexspline 3 is an external gear and the circular spline 2 is an internal gear. However, as in the previous four embodiments, the flexspline 3 is an internal gear and the circular spline 2 is an internal gear. It is also possible to form a strain wave gearing as an external gear.

Flex spline 3 is internal gear, circular spline 2
A first example of a strain wave gear device in which a is formed as an external gear
Figure 1(a), et al. A set of energized piezoelectric elements 2
The structure is the same as that of the wave gear device shown in the previous embodiment, except that the axis connecting the points 1 and 1 is the short axis, and the same effect can be obtained.

The scope of the present invention is not limited to the above examples, and various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. It is.

For example, in Embodiment I, the displacement direction of the piezoelectric element 21 may be not only in the axial direction of the flexspline 3 but also in the opposite direction, and it is sufficient that it is perpendicular to the axial line of the flexspline 3. Similarly, the direction of displacement of the piezoelectric element 21 in Example (2) is not limited to the direction toward the closed end of the flex-spline 3, but may also be in the opposite direction, as long as it is parallel to the axis of the flex-spline 3.

Furthermore, the piezoelectric element 21 can be placed either inside or outside the flexspline 3, and the distance from the flexspline 3 is not limited.

Further, if the direction of displacement given by the piezoelectric element 21 is perpendicular to the axis of the flexspline 3 (parallel to the axis when using the elastic member 40), there is no need to use the displacement direction changing means 8, but the piezoelectric element 21 is not perpendicular to the axis of the flexspline 3 (not parallel to the axis when the elastic member 40 is used), by using one or more displacement direction changing means 8, the direction of displacement can be changed to the direction as described above. It can be changed in a direction perpendicular to the axis (in a direction parallel to the axis when the elastic member 40 is used). Therefore, the piezoelectric element 21 can be arranged in any direction.

Further, in the above embodiment, the number of piezoelectric elements 21 is 12 or 8, but the number of piezoelectric elements 21 can be arbitrarily selected. However, the number of piezoelectric elements 21 is preferably a multiple of four.

The displacement directions of the piezoelectric element 21 shown in FIGS. 10 and 11 do not necessarily have to be displaced in both left and right directions in the figures, and the elastic member 40 can be activated even if the piezoelectric element 21 is displaced in only one direction.

The elastic member 40 in FIGS. 8 to 11 may be a single member, or a plurality of members may be arranged in parallel.

In addition to the unimorph type, a bimorph type piezoelectric element 21 can be used as the piezoelectric element 21, but the unimorph type piezoelectric element is more suitable for the wave generator of the present wave gear device.

As for the materials of the displacement generating means 7 and the displacement direction changing means 8, if the material is too hard, it will not deform, and if it is too soft, it will absorb the displacement of the piezoelectric element. It is preferable to have the following. The most preferable material is metal, but other than metal, ceramic, resin, etc. can also be selected as the material.

[Modified example]

FIGS. 12(a), 12(a), and 12(c) show an example of another type of wave gear device including a wave generator using a piezoelectric element.

Figures (a) and 3) are schematic diagrams showing the operating state of the wave gear device, and Figure (C) is a sectional view taken along the line X--X in Figure (a).

The wave gearing device 1 includes a circular spline 2, a flexspline 3, and a wave generator 4 that bends the flexspline 3 non-circularly and partially meshes with the circular spline 2. The wave generator 4 includes a plurality of piezoelectric elements 21 whose ends can be displaced both in a direction away from each other and in a direction in which they approach each other, and a piezoelectric element drive device (not shown) that sequentially selects and energizes the piezoelectric elements 21. ). The plurality of piezoelectric elements 21 are arranged at approximately equal intervals on the inner circumferential surface of the flexspline 3 so that the direction of displacement is in the circumferential direction of the flexspline 3. If the piezoelectric element 21 is displaced, the flexspline 3 is also displaced. In addition, the piezoelectric element driving device simultaneously urges the piezoelectric elements 21a arranged at both ends of the flexspline 3 in the diametrical direction to displace the flexspline 3 in a direction in which it is pulled (hereinafter referred to as the "pulling direction"). , the piezoelectric elements 21b disposed at both ends in the diametrical direction orthogonal to this diametrical direction are biased so as to be displaced in a direction that compresses the flexspline 3 (hereinafter referred to as the "compression direction").

The wave gear device I having the above configuration operates as follows.

As shown in FIG. 12(a), the piezoelectric element driving device urges the piezoelectric elements 21a disposed at both ends of the flexspline 3 in the diametrical direction so that the displacement direction becomes the tensile direction. The piezoelectric elements 21 are arranged at both ends of a diameter perpendicular to the diameter where the piezoelectric element 2ta is located.
b is also biased so that the direction of displacement is in the direction of compression. The piezoelectric elements 21a and 21b are joined to the inner surface of the flexspline 3, and when the piezoelectric elements 21a and 21b are displaced, the 7 flexspline 3 is also displaced. Therefore, piezoelectric element 2
The flexspline 3 expands around the flexspline 3 to which the piezoelectric element 21b is bonded, and contracts around the flexspline 3 to which the piezoelectric element 21b is bonded. By the operation of these piezoelectric elements 21a and 21b, the flexspline 3 is deformed into an elliptical shape with the short axis being the diameter connecting the piezoelectric elements 21a and the long side being the vertical axis connecting the piezoelectric elements 21b. Thereafter, a relationship is maintained in which the diameter connecting the pair of piezoelectric elements biased to be displaced in the tensile direction is orthogonal to the diameter connecting the pair of piezoelectric elements biased to be displaced in the compression direction. At the same time, the piezoelectric element is sequentially moved, for example, clockwise, by the piezoelectric element driving device to energize the piezoelectric element.

As a result, the meshing position between the flexspline 3 and the circular spline 2 changes from the position shown in FIG. 12(a) to the position shown in FIG.
Move sequentially to the positions shown in , as if rotated. In this way, while maintaining the above relationship, the piezoelectric element 2
By continuously energizing the circular spline 1, for example, if the circular spline 2 is fixed, during one revolution of the flex spline 3, the piezoelectric element 21 of the flex spline 3 has a smaller number of teeth than the circular spline 2. The output shaft 5 moves in the opposite direction to the biasing direction and connects to the flexspline 3 using this movement as an output (see Fig. 12 (C)).
It can be taken out from.

Note that various changes can be made in this modification as well.

For example, in this modification, a wave gear device is described in which the flexspline 3 is an external gear and the circular spline 2 is an internal gear, but the invention is not limited to this type. The same can be applied to wave gear devices of the type that are external gears.

Further, the number of piezoelectric elements 210 is also arbitrary, but it is preferably a multiple of four.

Furthermore, although either a unimorph type or a bimorph type piezoelectric element 21 can be used, a bimorph type piezoelectric element is more suitable in this modification.

〔Effect of the invention〕

According to the present invention, the displacement of the piezoelectric element can be amplified to sufficiently deflect the flexible gear in a non-circular manner, and furthermore, when the displacement direction needs to be changed during displacement amplification, the displacement direction can be changed. It is possible to realize a strain wave gearing device that can also be used.

[Brief explanation of drawings]

(a) of FIGS. 1, 3 to 5, and 7 to 11 are diagrams of the wave gear device according to an embodiment of the present invention when cut along a plane passing through the axis of the flexible gear. cross section,
(b) is a cross-sectional view taken along the line x-X in Figure (a), Figure 2 (a) and υ are schematic diagrams showing the displacement amplification mechanism of the displacement generating means, and Figures 6 (a) and 6) are displacement 12(a) and 12(b) are schematic cross-sectional views of a strain wave gearing device equipped with another type of wave generator using a piezoelectric element, and FIG. 12(C) is a schematic diagram showing the direction changing means. Cross-sectional view taken along line X-X in Figure (a), 1st
3 and 14 are cross-sectional views of a conventional wave gear device equipped with a wave generator using a piezoelectric element. [Explanation of symbols] 1... Wave gear device 2... Circular spline 3... Flex spline 4... Wave generator 5... Output shaft 6... Displacement generating means 7... Displacement generating means 8... Displacement direction changing means 9... Displacement amplification/displacement direction changing means 10... Wave gear device 11... Rigid circular internal gear 12... - Flexible external gear 13... Wave generator 15... Disk 16... Piezoelectric element 17... Piezoelectric element drive device 18... Output shaft 21.21 a, 2 l b---・Piezoelectric element 31...
... Portions that come into contact with the piezoelectric element 32.32 a, 32 b, 32 c, 32 d...
- Displacement amplification mechanism 33... Part 0 that contacts the back side of the tooth surface of the flexspline... Elastic member Oa, 40 b... End part 1 of the elastic member... Connecting member 1... ... Portion receiving displacement 2 ... Part that acts as a fulcrum 3 ... Part that transmits the amplified displacement 4 ... Fixed part 5 ... Fixed member 1 ... Point 2. 63... Part 4 of displacement direction changing means...
Fixed position 6... Point receiving displacement 6... Tip transmitting displacement 0... Hinge 8 (a) Figure 1 (b) ``8 Za Figure 2 (b) (a) ''X Figure 3 (b) Figure 5 (b) X-=-1 Figure 4 (b) (a) ''8 (a) Figure 8 (b) (a) LX (a) b) (a) [X x Figure 11 (b) Figure 13 Figure 14

Claims (7)

[Claims] (1) A wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, wherein the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. and displacement amplifying means for amplifying the displacement generated by the displacement generating means, the displacement generating means being arranged at approximately equal intervals around the axis of the flexspline on a plane whose displacement direction is perpendicular to the axis of the flexspline. The displacement amplification means includes a plurality of piezoelectric elements arranged radially in a direction, and a piezoelectric element drive device that sequentially selects and energizes the piezoelectric elements, and the displacement amplification means includes a portion that comes into contact with the piezoelectric element;
The displacement amplification mechanism includes a member having at least one displacement amplification mechanism and a portion that comes into contact with the back surface of the tooth surface of the flexspline, and the displacement amplification mechanism includes a portion receiving displacement, a portion acting as a fulcrum, and an amplified displacement A strain wave gear comprising a member having a part that transmits an amplified displacement, and the distance between the part that acts as a fulcrum and the part that transmits amplified displacement is longer than the distance between the part that acts as a fulcrum and the part that receives displacement. Device. (2) In a wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline noncircularly and partially meshes with the circular spline, the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. Displacement amplifying means for amplifying the displacement generated by the displacement generating means; and at least one displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, wherein the displacement generating means is configured such that the displacement direction is a plurality of piezoelectric elements arranged radially at approximately equal intervals on the circumference of a circle centered on the axis so as to be parallel to, or at an acute or obtuse angle to, the axis of the flexspline; The displacement amplification means includes a piezoelectric element drive device that sequentially selects and energizes the piezoelectric element, and the displacement amplification means includes a portion that abuts the piezoelectric element, at least one displacement amplification mechanism, and a portion that abuts the back surface of the tooth surface of the flexspline. consisting of a member having
The displacement amplification mechanism is composed of a member having a portion that receives displacement, a portion that acts as a fulcrum, and a portion that transmits the amplified displacement, and the distance between the portion that acts as the fulcrum and the portion that transmits the amplified displacement is The displacement direction changing means is longer than the distance between the part acting as a fulcrum and the part receiving displacement, and the displacement direction changing means has two parts extending in two directions from one point, and is fixed such that either position acts as a fulcrum. A strain wave gear device characterized by comprising a member that includes: (3) In a wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. The displacement generating means includes a displacement amplifying means for amplifying the displacement generated by the displacement generating means, and a displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, and the displacement generating means is configured such that the displacement direction is the same as that of the flexspline. a plurality of piezoelectric elements radially arranged at approximately equal intervals on the circumference of a circle centered on the axis so as to be parallel to the axis; and a piezoelectric element drive device that sequentially selects and energizes the piezoelectric elements. The displacement amplifying means includes a portion that comes into contact with the piezoelectric element;
The displacement amplification mechanism is made up of a member having at least one displacement amplification mechanism, and the displacement amplification mechanism is a member having a part receiving displacement, a part acting as a fulcrum, and a part transmitting the amplified displacement, and the displacement amplification mechanism acts as a fulcrum. The distance between the part and the part transmitting the amplified displacement is longer than the distance between the part acting as a fulcrum and the part receiving the displacement, and one end of the displacement direction changing means transmits the amplified displacement of the displacement amplifying mechanism. A wave gear device comprising an elastic member connected to a transmitting portion and having the other end fixed, and a direction of displacement transmitted by the amplified displacement transmitting portion is a direction toward the fixed other end. . (4) In a wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. Displacement amplifying means for amplifying the displacement generated by the displacement generating means; and at least one displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, wherein the displacement generating means is configured such that the displacement direction is A plurality of piezoelectric elements are arranged radially at approximately equal intervals on the circumference of a circle centered on the axis so as to form a certain angle with respect to the axis of the flexspline, and the piezoelectric elements are sequentially selected. a piezoelectric element drive device for energizing, and the displacement amplifying means includes a portion that comes into contact with the piezoelectric element;
The displacement amplification mechanism is made up of a member having at least one displacement amplification mechanism, and the displacement amplification mechanism is a member having a part receiving displacement, a part acting as a fulcrum, and a part transmitting the amplified displacement, and the displacement amplification mechanism acts as a fulcrum. The distance between the part and the part transmitting the amplified displacement is longer than the distance between the part acting as a fulcrum and the part receiving the displacement, and the displacement direction changing means has two parts extending in two directions from one point, At least one member is fixed such that one of its positions acts as a fulcrum, and one end is connected to a portion of the displacement amplification mechanism that transmits the amplified displacement, and the other end is a fixed elastic member. A wave gear device comprising a member, wherein the direction of displacement transmitted by the portion transmitting the amplified displacement is a direction toward the other fixed end. (5) A wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, wherein the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. and a displacement amplification/displacement direction changing means for amplifying the displacement generated by the displacement generating means and changing the direction of the displacement, and the displacement generating means is configured such that the direction of displacement is parallel to the axis of the flexspline. It consists of a plurality of piezoelectric elements radially arranged at approximately equal intervals on the circumference of a circle centered on the axis, and a piezoelectric element drive device that sequentially selects and energizes the piezoelectric elements, The displacement direction changing means includes an elastic member having one end connected to the piezoelectric element and the other end fixed, and the direction of displacement of the piezoelectric element is toward the fixed other end. Wave gear device. (6) A wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, wherein the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. At least one displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, and a displacement amplifying and displacement direction changing means for amplifying the displacement generated by the displacement generating means and changing the direction of the displacement. The displacement generating means includes a plurality of piezoelectric elements arranged radially at approximately equal intervals on the circumference of a circle centered on the axis of the flexspline so that the displacement direction forms a certain angle with respect to the axis of the flexspline. and a piezoelectric element drive device that sequentially selects and energizes the piezoelectric element, and the displacement direction changing means has two parts extending in two directions from one point, with either position acting as a fulcrum. The displacement amplification/displacement direction changing means includes an elastic member having one end connected to the piezoelectric element and the other end fixed, and the displacement direction of the piezoelectric element is fixed to the piezoelectric element. A wave gear device characterized in that the direction is toward the other fixed end. (7) In a wave gear device comprising a circular spline, a flex spline, and a wave generator that bends the flex spline non-circularly and partially meshes with the circular spline, the wave generator includes a displacement generating means, and a wave generator that partially meshes with the circular spline. The displacement generating means includes a displacement amplifying means for amplifying the displacement generated by the displacement generating means, and a displacement direction changing means for changing the direction of the displacement generated by the displacement generating means, and the displacement generating means has a displacement direction that is equal to or greater than the flexspline. a plurality of piezoelectric elements arranged at approximately equal intervals on the circumference of the circle so as to be tangential to a circle centered on the axis of the flexspline on a plane perpendicular to the axis of the flexspline; a piezoelectric element drive device that selects and energizes the piezoelectric element, and the displacement amplifying means includes a portion that abuts the piezoelectric element;
The displacement amplification mechanism is composed of a member having a part that receives displacement, a part that acts as a fulcrum, and a part that transmits the amplified displacement, and the part that acts as a fulcrum and the amplification part. The distance between the part that transmits the amplified displacement and the part that transmits the amplified displacement is longer than the distance between the part that acts as a fulcrum and the part that receives the displacement, and both ends of the displacement direction changing means are connected to the part that transmits the amplified displacement of the displacement amplification mechanism. A wave gear device comprising connected elastic members, wherein the directions of displacement transmitted by the amplified displacement transmitting portions are mutually directed toward the other end.