JPH081911Y2 - XY coordinate positioning mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an XY coordinate positioning mechanism used in a pen plotter, a robot or the like, and is characterized by a driving means in particular.

"Prior Art" Conventionally, a pen plotter shown in Fig. 6 is known as an apparatus using this type of XY coordinate positioning mechanism.

This is because the screw shaft 1 arranged in the X-axis direction, the blocks 3 and 4 are attached to the guide shaft 2, and the screw shaft 5 and the guide shaft bridged between the blocks 3 and 4 in the Y-axis direction. A pen carriage 7 having a built-in recording pen is attached to 6, and the screw shaft 1 is rotated by a stepping motor to reciprocate the block 3 along the screw shaft 1 to move the pen carriage 7 in the X-axis direction. Further, the pen carriage 7 is reciprocated in the Y-axis direction by rotating the screw shaft 5 with a stepping motor.

[Problems to be Solved by the Invention] However, in such a conventional XY coordinate positioning mechanism in a pen plotter, a stepping motor is used as a drive source to move the block 3 and the pen carriage 7. This rotary motion is
Since the linear motion is converted by the screw shaft 5, there is a drawback that the positioning accuracy is limited due to the backlash and accumulated error of the screw, and the high speed mobility is lacking.

Further, it is very difficult to machine the long screw shaft 1 and the screw shaft 5 having high accuracy such as straightness, and therefore, the moving distance of the block 3 and the pen carriage 7 is limited.

By the way, the applicant has devised an efficient ultrasonic linear motor utilizing the resonance state of the constituent members (Japanese Patent Application No. 63-6).
0713, Japanese Patent Application No. 63-60714). This comprises a traveling body (vibrating body) composed of at least one pair of legs that vibrate in a direction orthogonal to the rail, and a body that connects these legs and vibrates in the direction of the rail. The body and the body are vibrated so that their phases are appropriately different from each other so that they can travel on the rail.

The present invention aims to solve the drawbacks of the conventional XY coordinate positioning mechanism by providing a new XY coordinate positioning mechanism using the ultrasonic linear motor.

[Means for Solving the Problems] In order to achieve the above object, an XY coordinate positioning mechanism according to a first aspect of the present invention is a moving body that moves along a guide arranged in the X-axis direction. And an moving body that moves along a guide arranged in the Y-axis direction.
In the coordinate positioning mechanism, at least two or more legs arranged in the moving direction of each of the moving bodies, a body connecting the ends of the legs, the body, and the body. An ultrasonic linear motor, which is attached to the connecting portion with a tilt, is provided with a vibration source that vibrates the leg portion and the body portion, respectively. It is characterized in that the sources are simultaneously driven with a phase difference to excite elliptical vibration at the tips of the legs.

An XY coordinate positioning mechanism according to a second aspect of the present invention is a body for connecting a moving body with at least two or more legs arranged in a moving direction of the moving body and end portions of these legs. An ultrasonic linear motor comprising a vibrating body configured to vibrate when a voltage is applied to each of the leg portion and the body portion, and the tip of the leg portion is pressed against each of the guides. It is characterized in that each is provided, and each leg and the body of the vibrating body are simultaneously driven with a phase difference to excite elliptical vibration at the tip of each leg.

[Operation] In the XY coordinate positioning mechanism configured as described above, voltages having different phases are appropriately applied to the vibration sources of the leg and the body of the ultrasonic linear motor to expand and contract the leg and the body. And, the tip of the leg draws an elliptical locus that rotates in the same direction with respect to the center of the body. And in the guide,
Since the tips of the legs are alternately pressed toward one side, the moving body moves linearly in a certain direction together with the ultrasonic linear motor due to the reaction of the force.

[Embodiment] An embodiment in which the XY coordinate positioning mechanism of the present invention is applied to a pen plotter will be described below with reference to FIGS. 1 to 4.

In these figures, 11 and 12 are guide shafts fixed to the support plate 13 at intervals in the X-axis direction, and blocks 14 and 15 are moved in the axial direction on these guide shafts 11 and 12, respectively. It is freely inserted. Guide shafts 16 and 17 are bridged between the blocks 14 and 15 at intervals in the Y-axis direction, so that the blocks 14 and 15 are integrally moved. A pen carriage (moving body) 19 having a pen 18 attached to the guide shafts 16 and 17 has a through hole 19 formed therein.
A and 19B are fitted in the guide shafts 16 and 17, and are attached so as to be movable in the axial direction. The upper portion of the guide shaft (guide) 16 is cut to form a flat surface portion 16A, while the pen carriage 19 is formed with a penetrating portion 19C penetrating from the upper surface thereof to the through hole 19A. A box-shaped support member 20 is fixed to the upper surface of the with a screw 21 so as to close the opening above the penetrating portion 19C.

Reference numeral 30 denotes an ultrasonic linear motor. The ultrasonic linear motor 30 includes leg portions 31 and 32 that are parallel to each other and these leg portions.
A vibrating body 34, which is composed of a body portion 33 that connects one ends of 31 and 32, is made of an elastic material and has a substantially square cross-section and is formed in a U shape as a whole. The corner portions of the vibrating body 34 are leg portions 31, 32 and the body portion 33. Against
It is chamfered to form an angle of 45 degrees, and piezoelectric elements 36 and 37 are attached to the attachment surface 35 with an adhesive or the like. Here, as the material of the vibrating body 34, a metal material such as aluminum, duralumin, iron, brass or stainless steel, an inorganic material such as alumina, glass or silicon carbide, an organic material such as a polyimide resin or nylon can be used. . Further, the piezoelectric elements 36 and 37 are made of a laminated piezoelectric actuator or a single-plate piezoelectric ceramic, and are adapted to expand and contract in a direction orthogonal to the mounting surface 35.

The ultrasonic linear motor 30 is attached to the support member 20 as follows. That is, in the ultrasonic linear motor 30, the leg portions 31 and 32 of the ultrasonic linear motor 30 are arranged on the flat surface portion 16 of the guide shaft 16.
A small recess 33A formed in the central portion of the body 33 by being inserted into the penetrating portion 19C of the pen carriage 19 by being brought into contact with A.
Into the top wall 20A of the support member 20, a pointed tip of a pin 40 inserted so as to be able to advance and retreat toward the guide shaft 16 is inserted, and the pin 40 is provided between the top wall 20A of the support member 20 and the body portion 33. A coil spring (elastic member) 41 is attached to surround the ultrasonic linear motor 30 so that the ultrasonic linear motor 30 is prevented from moving with respect to the support member 20, and its leg portions 31 and 32 are guided by the guide shaft.
It is pressed against the flat surface portion 16A of 16.

On the other hand, the block (moving body) 14 is similarly provided with an ultrasonic linear motor 30. That is, the ultrasonic linear motor 30 has its legs 31, 32 guided by the guide shaft (guide) 11
Of the support member 20 is inserted into the through portion 14C of the block 14 by being brought into contact with the flat surface portion 11A of the supporting member 20,
The tip end of the pin 40 inserted in the is inserted and is prevented from moving with respect to the support member 20, and the coil spring 41 presses the leg portions 31 and 32 thereof against the flat surface portion 11A of the guide shaft 11. There is.

In the pen plotter using the XY coordinate positioning mechanism configured as described above, in order to move the pen carriage 19 by the ultrasonic linear motor 30, the first piezoelectric element 36 is used.
The voltage to be applied to Va is E = sin · ωt, and the voltage of Vb = E · sin (ωt−π / 2) is applied to the second piezoelectric element 37. Then, each end is subjected to the following vibrations by the piezoelectric elements 36 and 37. In the first leg portion 31, X ₁ = A · sin (ωt + π / 2) Y ₁ = B · sin (ωt + π), while in the second leg portion 32, X ₂ = A · sin ωt Y ₂ = B・ Vibrate like sin (ωt + π / 2).

That is, the tips of the leg portions 31 and 32 make an elliptical vibration, and the vibrations of the first leg portion 31 and the second leg portion 32 are different in phase by 90 degrees. The legs 31, 32
Since the tips of are always pressed in one direction,
The reaction causes the pen carriage 19 to move to the ultrasonic linear motor 30.
At the same time, it moves in one direction along the guide shaft 16.

To change the direction of movement, the voltage applied to the second leg portion 32 may be Vb = E · sin (ωt + π / 2).

Similarly, the block 14 can be moved along the guide shaft 11 by the ultrasonic linear motor 30.

In such an XY coordinate positioning mechanism for a pen plotter, the tip ends of the leg portions 31 and 32 are caused to oscillate by vibrating at the natural frequency of the moving body 34, whereby the pen carriage 19 is moved to the leg portion. Since it is moved by the frictional force between the tip ends of 31, 32 and the guide shaft 16, the pen carriage 19 can be moved at a high speed and can be positioned with high accuracy. Further, there is an advantage that it works as a brake when the power is in the "OFF" state. The same effect can be obtained for the block 14.

In addition, the pen carriage 19 or the block 14 can be directly driven only by the ultrasonic linear motor 30 without using a transmission mechanism such as a screw shaft.
In addition, since the ultrasonic linear motor 30 does not have a complicated composition including coils and magnets like a stepping motor but has a simple structure, the entire structure can be made small and lightweight.

Furthermore, since the screw shaft is not used, the pen carriage
The moving distance of 19 and the block 14 can be lengthened.

Furthermore, since no magnetic field is generated, no adverse effect is exerted on these media in the processing for media for magnetic recording, for example.

Moreover, since the piezoelectric elements 36, 37 are not configured to directly contact the guide shaft 16, the piezoelectric elements 36, 37 due to vibration
It is possible to prevent cracks and the like from having a high durability.

FIG. 5 shows another example of the ultrasonic linear motor.

In the figure, 71 and 72 are legs, and 73 is a body. These are laminated piezoelectric actuators each formed in a columnar shape with a square cross section.
Each expands and contracts in the longitudinal direction. At both ends of the body portion 73, regular hexahedral iron blocks 74 and 75 are inserted into the holes 76 formed in the surfaces of the blocks 74 and 75, and the ends of the body portion 73 are joined together by using epoxy resin or the like. Has been done. These blocks 74, 75
Leg portions 71 and 72 are joined to the other surface in the same manner to form a U-shaped vibrator 77 as a whole.

In the ultrasonic linear motor 70 configured as above, the voltage applied to the piezoelectric actuator of the body 73 is Va = Ex · sinωt, and the legs 71 and 72 have the first leg 71 and Vb = Ey · sin (ωt + 3π / 2) When a voltage of Vc = Ey · sin (ωt + π / 2) is applied to the second leg portion 72, the tips of the leg portions 71 and 72 each make an elliptical vibration. Since the vibrations of the first leg 71 and the second leg 72 are X ₁ = −X ₂ and Y ₁ = −Y ₂ , the phases are different by 180 degrees.

Therefore, the pen carriage 19 or the block 14 can be moved also by such an ultrasonic linear motor 70.

In order to reverse the moving direction, the phase of the voltage applied to the body 73 may be Va = Ex · sin (ωt + π).

In the above embodiment, the XY coordinate positioning mechanism according to the present invention is applied to the pen plotter, but the invention is not limited to this and can be applied to a robot or the like.

[Advantages of the Invention] As described above, the XY coordinate positioning mechanism according to the first aspect of the present invention has at least two leg portions arranged in the moving body in the moving direction of the moving body. And a vibration source that is attached to the body portion that connects the end portions of these leg portions and the connection portion that connects the leg portion and the body portion in an inclined manner and that vibrates the leg portion and the body portion, respectively. The ultrasonic linear motor is formed by pressing the tips of its legs to the guides, and the vibration sources are simultaneously driven with a phase difference to excite elliptical vibration at the tips of the legs.

An XY coordinate positioning mechanism according to a second aspect of the present invention is a body for connecting a moving body with at least two or more legs arranged in a moving direction of the moving body and end portions of these legs. An ultrasonic linear motor comprising a vibrating body configured to vibrate when a voltage is applied to each of the leg portion and the body portion, and the tip of the leg portion is pressed against each of the guides. Each of them is provided so that each leg and the body of the vibrating body are simultaneously driven with a phase difference to excite elliptical vibration at the tip of each leg.

Therefore, in the XY coordinate positioning mechanism of the present invention, the vibrating body composed of the leg portion and the body portion is vibrated at its natural frequency to cause the tip of the leg portion to make an elliptical vibration, thereby moving the moving body to the leg. Since it is moved by the frictional force between the tip of the section and the guide, the moving body can be moved at high speed and can be positioned with high accuracy. further,
When the power supply is in the "OFF" state, the moving body is locked and there is an advantage that the holding mechanism is unnecessary.

In addition, the moving body is directly driven only by the ultrasonic linear motor without using a transmission mechanism such as a screw shaft as in the past, and the ultrasonic linear motor has a simple structure. You can

In addition, since the screw shaft is not used, the moving distance of the moving body can be lengthened.

Furthermore, since the vibration source is not in direct contact with the guide, it is possible to prevent the vibration source such as a piezoelectric element from cracking and to have high durability.

Moreover, since no magnetic field is generated, it is possible to obtain an effect that the magnetic field can be applied to a device that requires such consideration.

[Brief description of drawings]

1 to 4 are views showing an embodiment of a pen plotter using the XY coordinate positioning mechanism of the present invention.
1 is a perspective view, FIG. 2 is a cross-sectional view of a pen carriage portion,
FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a sectional view of a block portion. FIG. 5 is a diagram showing another example of the ultrasonic linear motor according to the present invention. FIG. 6 is a perspective view showing a pen plotter using a conventional XY coordinate positioning mechanism. 11 …… guide axis (guide), 12 …… guide axis, 14 …… block (moving body), 15 …… block, 16 …… guide axis (guide), 17 …… guide axis, 19 …… pen carriage ( Moving body), 19A, 19B ... through hole, 19 ... through portion, 20 ...
… Supporting member, 20A… Top wall, 30… Ultrasonic linear motor, 31, 32… Leg part, 33… Body part, 34… Vibrating body, 36,
37 …… Piezoelectric element, 40 …… Pin, 41 …… Coil spring (elastic member), 70 …… Ultrasonic linear motor, 71,72 …… Legs,
73 …… Body, 74,75 …… Block, 77 …… Vibrator.

Claims (2)

[Scope of utility model registration request] 1. An XY coordinate positioning mechanism having a moving body moving along a guide arranged in the X-axis direction and a moving body moving along a guide arranged in the Y-axis direction. At least two or more legs arranged in the moving direction of the moving body, a body connecting the ends of the legs, and an inclination to the connecting portion between the legs and the body. And an ultrasonic linear motor that is attached and has a vibration source that vibrates the legs and the body, respectively,
The tip of the leg is provided in pressure contact with each of the guides, and the vibration sources are simultaneously driven with a phase difference to excite elliptical vibration at the tip of the leg. Characteristic XY coordinate positioning mechanism. 2. An XY coordinate positioning mechanism having a moving body which moves along a guide arranged in the X-axis direction and a moving body which moves along a guide arranged in the Y-axis direction. The moving body includes at least two legs arranged in the moving direction of the moving body and a body connecting the ends of these legs, and each of the legs and the body are respectively formed. An ultrasonic linear motor having a vibrating body configured to vibrate when a voltage is applied is provided by pressing the tips of the legs to the guides, and the legs and the body of the vibrating body. And Y are simultaneously driven with a phase difference to excite elliptical vibration at the tips of the legs, and an XY coordinate positioning mechanism.