JPH0760587A - Positioning type actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a small actuator suitable for positioning with a short stroke of 1 mm or less [Structure] A fixed base is provided with a fixed shaft and an output shaft, and an eccentric ring integrated with the output shaft and the fixed shaft are provided. In between, an electromechanical transducer such as a laminated piezoelectric element was sandwiched at both ends so that it could slide through bearings, and a preload was applied to the electromechanical transducer by a displacement output lever fixed to the output shaft and a load spring. Try to call. [Effect] Compact and lightweight, with excellent instantaneous power, suitable for high-speed operation.
It is suitable for maintaining accuracy because there is little electric energy loss and less heat generation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This is a field that requires precise positioning with a short stroke of 1 mm or less in semiconductor assembly equipment such as positioning of wire clamps for wire bonders for IC assembly or information communication related equipment.

[0002]

2. Description of the Related Art Servo technology using a motor and a ball screw or a cam is well known for positioning a widely used robot, machine tool and the like. This is a region of 1 mm or more in terms of stroke. On the other hand, for precise positioning of semiconductor manufacturing equipment such as a stepper, a fine adjustment mechanism for a stroke of 10 μm or less is known in addition to the technique of the stroke region. In this stroke region of 10 μm or less, a piezoelectric element or a magnetostrictive element is used as an actuator. However, in an assembly machine such as a wire bonder, for example, a wire clamp feed control requires positioning within and outside the stroke of 1 mm, and conventionally, general-purpose techniques such as a motor and a cam have to be used.
For this reason, it is difficult to reduce the size of the device, and it has not been possible to mount the device on a head rotation type wire bonder for controlling the feed of the wire clamp. Therefore, at present, stroke 1
It is considered that a small actuator suitable for servo positioning is not found in the area inside and outside the mm.

[0003]

The piezoelectric element or the magnetostrictive element will be hereinafter referred to as an electromechanical transducer. Since the electromechanical converter utilizes the strain generated by the electric means, the output displacement can be suppressed to about 10 μm at the maximum.
Therefore, in order to have a stroke of about 1 mm, a displacement magnifying mechanism of up to about 100 times must be realized. This is the first issue. The next problem is to incorporate a bending moment absorbing element in the displacement magnifying mechanism because the electromechanical transducer is easily damaged when a bending moment is applied.

[0004]

In order to solve the above problems, in the present invention, a fixed base is provided with a fixed shaft and a rotatable output shaft, and between an eccentric ring integral with the output shaft and the fixed shaft, The electromechanical converter is sandwiched at both ends thereof via bearings so as to be slidable, a displacement output lever is fixed to the output shaft, and a preload is applied to the electromechanical converter by a load spring.

[0005]

When the eccentric amount of the eccentric wheel integrated with the output shaft is 1 mm and the length of the displacement output lever is 100 mm, the displacement magnification ratio becomes 100 times. This is the principle of "leverage". Since the bearings are introduced at both ends of the electromechanical transducer, there is substantially no bending moment acting on the electromechanical transducer during operation.

[0006]

EXAMPLE FIG. 1 shows an example of the present invention. 1 in the figure
Is a base, 2 is a laminated piezoelectric element, 3a and 3b are bearings that can freely slide with respect to the fixed shaft 4 and the eccentric ring 7, respectively, and a solid powder lubricating layer 13 such as molybdenum disulfide is used.
A low friction state is maintained by a and 13b. The bearings 3a and 3b are bonded to the laminated piezoelectric element 2, respectively. Reference numeral 5 denotes a DC variable power source that drives the laminated piezoelectric element 2, and the laminated piezoelectric element 2 expands according to the output voltage thereof. Further, by short-circuiting the output terminal of 5, the laminated piezoelectric element 2 can be returned to the state before being stretched. As shown in FIG. 2, the eccentric wheel 7 is integrated with the output shaft 8, and the output shaft 8 is rotatably supported by the bearing 6 with respect to the base 1. A displacement output lever 9 is fixed to the output shaft 8 and a compressing force is always applied to the laminated piezoelectric element 2 by a load spring 10 via a pin 11. This compressive force absorbs the play of the displacement magnifying system. A pin 12 for taking out the displacement is driven into one end of the displacement output lever 9. When the laminated piezoelectric element 2 extends, the pin 12 is displaced as shown by the arrow in FIG. The laminated piezoelectric element 2 has a cross section of 5 mm square and a length of 18
A polarized film having a size of mm was used, and a length of about 7 μm was extended by applying 50 VDC. An output displacement of 210 μm was obtained by this mechanism using a displacement output lever having an eccentricity of 1.5 mm and a long arm length of 45 mm. At this time, since the laminated piezoelectric element 2 can exert a force of about 100 N, the force excluding the preload of the load spring 10 can be taken out from the output pin. If a wire clamp of the wire bonder is attached instead of the displacement output lever, it can be used as it is for the feed control of the wire clamp.

[0007]

The present positioning actuator is small and lightweight, has excellent instantaneous power, and generates little heat. Therefore, it is high-speed and highly accurate. It is most suitable for feed control of wire clamp of head rotation type wire bonder and also fills the blank part of conventional technology as an actuator with a small stroke of 1 mm in and out. The wire clamp is just one example, and has versatility that can be widely applied to other things.

[Brief description of drawings]

[FIG. 1] An embodiment according to the present invention

[Fig. 2] ... Top view of what is shown in Fig. 1 from above.

[Explanation of symbols]

 1 ・ ・ ・ ・ Fixed base 2 ・ ・ ・ ・ Laminated piezoelectric element 3 ・ ・ ・ ・ Bearing 4 ・ ・ ・ ・ Fixed shaft 7 ・ ・ ・ ・ Eccentric ring 8 ・ ・ ・ ・ Output shaft 9 ・ ・ ・ ・ Displacement output lever

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 41/083

Claims (1)

[Claims] 1. A fixed base is provided with a fixed shaft and a rotatable output shaft, and between an eccentric ring integral with the output shaft and the fixed shaft,
Positioning configured by sandwiching the electromechanical transducer at both ends so that it can slide through bearings, fixing the displacement output lever to the output shaft, and preloading the electromechanical transducer with a load spring. Actuator