JP2724112B2 - Stepping air motor and semiconductor inspection device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic motor,
In particular, the present invention relates to a stepping air motor that rotates step by step in synchronization with an air pulse (pneumatic pulse).

[0002]

2. Description of the Related Art In general, a semiconductor inspection apparatus for automatically contacting a lead of an IC (semiconductor integrated circuit) package with a test socket and inspecting the electrical characteristics of the IC is known as an I.
In the process of feeding the C package to the socket, the IC package sequentially and horizontally conveyed by the conveyor is moved in the Z-axis direction (upward).
And then transported to the position directly above the socket in the X-axis direction (horizontal), and then lowered in the -Z-axis direction to
The process is performed in the order in which the leads of the C package are brought into contact with the socket, and the process of returning the IC package from the socket is performed in the reverse order of the feeding process. With the recent increase in the number of pins and miniaturization of IC package leads, accurate contact with sockets has become increasingly difficult. In recent years, high temperatures (for example, 15
0 ° C) or low temperature (for example, -50 ° C)
There is an increasing demand for checking the strict specifications of semiconductor inspection equipment that responds to such strict requirements. In the process, in addition to the above-described two-axis (X-axis, Z-axis) control, two-axis control for each test object (fine adjustment θ of the rotation angle of the IC package and fine adjustment Y-axis) is required. That is, multi-axis control in a thermostat is required.

[0003]

By the way, an electric motor is generally considered as a motor for positioning and driving an IC package at a minute resolution. However, at high temperatures, the windings and contacts of the electric motor are significantly deteriorated, and the endurance is deteriorated. Inferior in properties and cannot be used in practice. In addition, there is also a problem of inspection reliability that electromagnetic noise is generated when an electric motor is driven by an electric pulse in a semiconductor inspection device for inspecting electrical characteristics, and thus the inspection environment is electrically disturbed.

[0004] In view of the above problems, a first object of the present invention is to use an air pulse (pneumatic pulse) to enable a highly reliable step rotation even in a high-temperature and low-temperature environment. A second object of the present invention is to make it possible to inspect a fine pitch IC even at high and low temperatures by using the stepping air motor. It is an object of the present invention to provide an improved semiconductor inspection device.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention seeks to obtain a stepwise rotational force by an air pulse. That is, according to the present invention, the revolving angle 2π / n is synchronized with the pulse by supplying the n-phase (n ≧ 3) air pulse.
In a stepping air motor having a revolving mechanism having a revolving member that revolves in increments of radians and a revolving / rotating conversion mechanism that takes out a revolving motion on an output shaft based on the revolving motion of the revolving member, the revolving mechanism is , In addition to the above revolving rotators,
A revolving guide mechanism that restricts the rotation of the revolving element to a revolving motion of a predetermined revolving diameter, and a circular path for each of the air pulses supplied at n equal points of the revolving circle from the revolving center with respect to the revolving element. And a revolving gear drive mechanism driven by a force acting in a direction passing through a point where the transition occurs.

Here, as the revolution / rotation conversion mechanism, a hypocycloid reduction mechanism having an internal gear and a pinion that rotates internally can be used. While it is possible to configure the internal gear to make a revolving motion and the pinion to make a self-rotating motion, in a miniaturized configuration of the motor, conversely, the pinion revolves following the revolving element and the internal gear Preferably has an output shaft.

Here, as a specific configuration of the revolving mechanism, a pneumatic linear actuator arranged in each of the n equally-divided radial directions of the revolving member can be adopted. In this case, assuming that the revolving diameter of the revolving element is D and the linear movement stroke of the pneumatic linear actuator is L, L = D ｛1-cos
It is desirable that the relational expression of (2π / n)｝ / 2 holds.

As a specific configuration of the pneumatic linear actuator, there is provided a pressing member which performs a feeding operation by the air pulse supplied to a cylinder chamber of an air cylinder and presses a pressed surface thereof without being connected to the revolving element. The pressing member has a concave air buffer chamber that opens to the pressed surface side, and a vent that communicates the air buffer chamber with the cylinder chamber. Further, it is desirable that the ventilation hole is a plurality of small ventilation holes, and that the cylinder chamber is provided with a spring means for constantly urging the pressing member elastically in the feeding direction. A coil spring is preferably used as the spring means.

On the other hand, as the revolving guide mechanism, an annular guide groove or a crank mechanism can be adopted, but an eccentric bearing mechanism using a ball bearing is preferable.
Then, it is desirable to provide three or more eccentric bearing mechanisms on the revolving rotator.

The stepping air motor having the above-mentioned structure is suitable for use in a high-temperature environment, and a lead of an IC package is contacted with a test socket provided in a constant temperature bath in a semiconductor inspection apparatus. It can be used as a positioning motor for performing the positioning.

[0011]

When a series of n-phase air pulses are supplied, the orbital element of the orbital mechanism rotates one revolution without rotating, and the output shaft of the orbital / rotary conversion mechanism rotates by the orbital motion of the orbital element.

[0012] In one air pulse, the revolving element has a revolving angle of 2π.
/ N radians, so that the output shaft rotates by a step angle corresponding to this. Therefore, in order to obtain a desired rotation angle, it is sufficient to supply a pulse number of a quotient obtained by dividing the rotation angle by the step angle. Such an air motor that rotates in a step-by-step manner in synchronization with an air pulse can be used at a high temperature, and can be used as a fine positioning motor for an IC package provided in a constant temperature chamber in a semiconductor inspection device. . In other words, since the X, Y, Z, and θ axes can be controlled at a high temperature, the fine pitch IC package can be inspected at a high temperature. In addition, since the air drive is used, no electromagnetic noise is generated, and the measurement environment does not need to be electrically disturbed.

By the way, there is known an air motor in which the tip ends of rods of a plurality of air cylinders are connected to a crankpin to rotate a crankshaft. When used as a servomotor, it is necessary to detect the rotation of the crankshaft and perform open / close feedback control of an electromagnetic valve or the like. However, in the present invention, since the motor is rotated stepwise by air pulse driving, feedback control is unnecessary, and the configuration of the control system can be eliminated.

In particular, in the present invention, after the orbital member is restricted only to the orbital motion by the orbital guide mechanism, the orbital drive mechanism causes the supply of the air pulse at every n equal points of the orbital circle from the orbital center. Since the orbit is driven by a force acting in a direction passing through the point where the orbit changes cyclically, the orbit is pulse-synchronized along the orbit guide mechanism and the orbit angle 2π / n.
Revolves incrementally in radians. At the end point of each step, the direction of the force acting on the orbit is substantially orthogonal to the orbital direction, and the work at that time disappears, so that the orbit is easily stopped at the end point. For this reason, a stepping air motor with a high step angle can be realized.

When the revolving element driving mechanism is a pneumatic linear motion actuator arranged in n equally divided radial directions of the revolving element, the revolving diameter of the revolving element is D, and the linear motion stroke of the pneumatic linear actuator is Assuming that L, if the relational expression of L = D {1−cos (2π / n)} / 2 holds, the end point of the step is pushed over, so that 2π / n radians of high precision can be obtained. The orbit revolves at the step angle.

Further, the pneumatic linear actuator according to the present invention has a pressing member for pressing the surface to be pressed without being connected to the revolving member when performing the feeding operation by the air pulse supplied to the cylinder chamber of the air cylinder. The pressing member has a concave air buffer chamber that opens to the pressed surface side, and a vent that communicates the air buffer chamber with the cylinder chamber. According to such a pneumatic linear actuator, since the pressing member is not connected to the revolving element, the pressing member operates following the high-frequency air pulse. In addition, the compressed air flows from the cylinder chamber into the concave air buffer chamber that opens to the pressed surface side through the ventilation hole by the supply of the air pulse, so that during the pressing process, compressed air nodules are generated in the air buffer chamber. Therefore, the orbit is pressed in an action manner. For this reason, even if an on-plane sliding motion occurs between the pressed surface and the pressing member, the contact resistance is small, and drive loss and abrasion can be reduced. When the ventilation holes are provided as a plurality of small ventilation holes, the compressed air flows into the air buffer chamber evenly, so that the generated compressed air nodules are less likely to be biased, and the pressed surface of the orbital rotor is pressed. Can be pressed face to face. Further, when the cylinder chamber is provided with a spring means for constantly urging the pressing member elastically in the feed-out direction, even if all the pressing members are not excited, the elastic force is applied to the pressed surface of the revolutor. Leakage in the initial stage of air pulse application does not occur because of the pressing, and the rising of the pressing operation is fast, and at the end of air pulse application, the revolving member is pressed by another pressing member, so that the excessive advance of the step angle is suppressed. Is done. In addition, since air bleeding is suppressed, silence can be improved.

When an eccentric bearing mechanism is used as the revolving guide mechanism, guide control can be achieved by rolling contact, so that the drag (resistance) for the guide can be reduced.
Smooth movement can be realized. In addition, in the configuration in which the eccentric bearing mechanism is provided at three or more locations on the revolving element, the idea of the eccentric bearing mechanism can be eliminated, and the revolving motion can be performed without any trouble even when the revolving element is stopped at any position. realizable.

[0018]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic view conceptually showing a stepping air motor according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the structure of the stepping air motor.
3A is a cross-sectional view taken along the line IIIa-IIIa 'of FIG. 2, and FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb' of FIG.

First, the principle of the stepping air motor of this embodiment will be described with reference to FIG. In the stepping air motor 100 of the present example, for example, a three-phase cyclic switching valve (rotary valve) 150 uses three-phase (phase difference 120 °) air pulses (AP1, AP2, AP3) as a driving energy source. In the embodiment, the three solenoid valves are sequentially switched and used by an electric signal. However, if the switching order is reversed, the stepping air motor of this embodiment rotates in the reverse direction.

The stepping air motor 100 revolves in a step-by-step manner at a revolving angle of 120 ° in synchronism with the supply of three-phase air pulses (AP1, AP2, AP3) from a three-way cyclic switching valve (rotary valve) 150. Revolving mechanism 10 having a rotor (rotor) 11 and its revolving element 1
An output shaft 21a has a revolution / rotation conversion mechanism (hypocycloid reduction mechanism) 20 for taking out rotation on the basis of the revolution movement at the revolution diameter D of 1.

The revolving mechanism 10 includes a revolving guide mechanism 12a to 12c (12) in addition to the revolving element 11 and a revolving element driving mechanism (pneumatic element) for revolving the revolving element 11 by 120 ° in increments of 120 ° each time an air pulse arrives. Linear actuator) 13a-
13c (13). The revolve 11 is formed in an equilateral triangular shape by three pressed surfaces 11a to 11c, and the radiating portions 15a to 1 integrally project outward from respective vertexes.
Revolution guide pins 16a to 16c are implanted in the thickness direction of the revolving element 11 in 5c. The revolving guide mechanism 12 is a mechanism for defining the revolving guide pin 16 in a locus having a diameter D, and may be an annular guide groove into which the revolving guide pin 16 is inserted, or may be a crank mechanism using a link. In this embodiment, as will be described later, an eccentric bearing mechanism is provided in which a revolving ball bearing for bearing the revolving guide pin 16 and a revolving bearing having the revolving center O of the revolving guide pin 16 as the center of rotation are eccentric.

The reciprocator driving mechanisms 13a to 13c are provided with air cylinders 13 for receiving supply of air pulses AP1 to AP3.
aa, 13ba, 13ca, and a revolving member pressing member (air) that expands and contracts linearly by increasing and decreasing the air pressure in the cylinder chamber to press the pressed surfaces 11a to 11c toward the revolving center (center of gravity) of the revolving member 11. Piston) 13ab, 13
bb, 13cb, and three revolving element driving mechanisms 1
3a to 13c are 120 with respect to the revolving center S of the revolving rotator 11.
It is arranged in three directions of radiation at intervals of °. The revolution / rotation conversion mechanism 20 of this example is a hypocycloid reduction mechanism, which has a pinion (external gear) fixed to the revolving element 11 and an output shaft 21a, as will be described later, and has a smaller number of teeth than the pinion 22. The pinion 22 has an internal gear 21 that meshes in an inward direction with a pitch circle that is larger by the difference and that rotates by the difference in the number of teeth for each revolution of the pinion 22. It should be noted that, contrary to the hypocycloid reduction mechanism of the present embodiment, the reciprocating internal gear and a pinion having a rotation output shaft may be used.

In such a basic configuration, when the three-way cyclic switching valve 150 communicating with the compressed air source operates in a predetermined sequence, the output ports P1 to P3
, The air pulses A1 to A3 are supplied to the revolving element driving mechanism 13 of the stepping air motor 100 cyclically.
That is, the air pulse A1 of the first phase is applied to the air cylinder 13a.
The air pulse A2 of the second phase, which is delayed by 120 ° from the air pulse A, is supplied to the air cylinder 13ba, and the air pulse A3 of the third phase, which is delayed by 120 ° from the air pulse A2, is supplied to the air cylinder 13ac. By supplying these series of air pulses, each of the orbital pressing members 13a
b, 13bb, and 13cb are sequentially extruded by a stroke L in the direction of the arrow (the direction toward the center of the orbiter). First, when the first-phase air pulse A1 is supplied,
Since the rotator pressing member 13ab pushes the pressed surface 11a of the rotator 11 while being extended in the direction of the arrow, the rotator 11 is moved in parallel from the solid line start position shown in FIG. 1 to the one-dot chain line end position. The translation process, for example, the center of gravity of the Kotenko 11 is to move from point P ₁ to point P _2, Kotenko 11 also Kotenko pressing member 13ab is in linear motion in the direction of the arrow
Does not move directly, but the revolving element 11a is controlled by the revolving motion of the revolving guide mechanisms 12a to 12c as revolving guide means.
The center of gravity of the revolution diameter D of the revolution center S from the point P ₁ of 120 °
So that the from the point P ₂ via the arc. After the step of the revolution angle 120 °, when the second-phase air pulse A2 is supplied to the air cylinder 13ba, the revolving member pressing member 13bb pushes the pressed surface 11b of the revolving member 11 while being extended in the arrow direction. Therefore, the revolving element 11 revolves from the starting position indicated by the alternate long and short dash line shown in FIG. Similarly, when the air pulse A3 of the third phase is next supplied to the air cylinder 13ca, the revolving member pressing member 13cb pushes the pressed surface 11c of the revolving member 11 while being extended in the arrow direction. From the starting position indicated by the two-dot chain line shown in FIG. 1, it is moved by orbiting at an orbital angle of 120 ° with the orbital diameter D at the end position of the solid line, and the first orbital operation is completed. Therefore, when three air pulses are generated, the revolving element 11 suppresses the rotation and makes one revolution of the revolving diameter D. For example, in the three-way cyclic switching valve 150 of the present example, an air pulse of 90 pulses / second is supplied, so that the revolving element 11 revolves 30 times per second.

Here, when a single air pulse is applied, the orbit 11 reliably revolves by a step angle of 120 °.
Consider whether the center of gravity is away from point P ₁ and matches point P ₂ . In a state where the frequency of the air pulse is relatively low and the air pressure is not too high, when the revolving member pressing member 13ab is extended by a stroke L = 3D / 4 by one air pulse, the revolving member 11ab is pushed out and the center of gravity of the revolving member 11 becomes FIG.
Is Kitasa has from the point P ₁ as shown in (a) to the point P _2.
Angle between the starting point P ₁ in the track tangential direction T and the pressing force F begins to revolve while the relatively light drag Kotenko 11 receives at 30 °, the track tangential direction T at the position where the revolution angle becomes 30 °
And the pressing force F become zero, then the angle formed by the two gradually increases and reaches 90 ° when the point P ₂ is reached.
1 stops. The rotator 1 is driven by the rotator pressing member 13ab.
Even pushed directly 1 center of gravity to the point P _2, for example because Kotenko 11 at no load has inertia of its own revolution course of 120 °, the point is the center-of-gravity point of Kotenko 11 P There is a concern that you will pass by ₂ . However, in reality, even in the no-load state, the friction of the revolutor guide mechanism 12 and the friction of the revolving / rotation conversion mechanism 20 and the like exist, and the revolutor pressing member 13ab stops at the push-off level of the revolving member pressing member 13ab. This is because it exhibits a stopper function does not become excessively overrun condition from point P _2. As described later in the embodiment shown in FIG. 2, the revolution transducer drive mechanism 13 function features coil springs, the braking force due to the spring bias when the center of gravity is from the point P ₂ is adapted to act . Therefore, immediately after press cutting stroke L is only on the center-of-gravity point is attenuated vibration in small before and after the point P ₂ near the accuracy of stepping rotation angle is high.

On the other hand, when the frequency of the air pulse is increased,
It can be assumed that the revolving rotator 11 has not reached the stepping angle of 120 ° during one air energizing period (period of ３ of one cycle), and is out of synchronization. Such a defect is caused by
1 tends to occur when the inertia is large, the load is high, or the air pressure is low. The simplest countermeasure is to set the air pressure to a sufficient value, for example, to increase the air pressure linearly when high-speed rotation is expected. Although the present embodiment is a three-phase air motor using three-phase air pulses, a four-phase air motor using four-phase air pulses or a multi-phase air motor more than that can be easily understood. For example, in a four-phase air motor, as shown in FIG. 4B, the center of gravity of the orbital revolves _{one step at} a time in the order of Q ₁ → Q ₂ → Q ₃ → Q ₄ → Q ₁ . One step angle is 90 °, stroke L
At this time, the revolution diameter D '= 2L. As described above, in the air motor having more than three phases, the step angle is reduced, and the rotational resolution (rotation angle index) is improved. However, since four or more revolving element drive mechanisms are required, the number of parts is increased, and it becomes an obstacle to a small configuration. From this point, it can be said that a three-phase motor is preferable. In general, in the case of an n-phase motor, the following relational expression is established between the revolution diameter D and the linear stroke L in order to obtain an accurate step angle 2π / n radian.

L = D {1−cos (2π / n)} / 2 As described above, the orbital rotor 11 orbits with the orbital diameter D by three air pulses. Since the pinion 22 is integrally formed on the revolving element 11 or is fixed separately, the pinion 22 does not rotate and revolves along the same locus as the revolving element 11 revolves. When the revolving element 11 revolves by _one point at the point P ₁ → P ₂ → P ₃ → P ₁ , the internal gear 21 meshing with the pinion 22
Rotates by the number of teeth difference. In this example, since the difference in the number of teeth is 1, the number of teeth Z 'of the pinion 22 is 29, and the number of teeth Z of the internal gear 21 is 30, the internal gear 21 rotates 360 ° / 30 in one revolution of the revolutor 11. = 12 °. That is, 1
The output air shaft 21a is rotated by 4 ° by the emitted air pulse. The revolution / rotation conversion mechanism 20 converts the revolution into rotation, of course. However, since it is a hypocycloid deceleration mechanism, the speed reduction ratio is 30 and the rotation angle index resolution is enhanced. If a hypocycloid reduction mechanism having a reduction ratio higher than this is used, the resolution can be further improved.

Next, a specific description of the present embodiment will be given with reference to FIGS. Stepping air motor 10 of this example
Numeral 0 has a small external dimension of a substantially straight shape with a length, width and height of about 2.5 cm, and a revolving gear drive mechanism 13 has an end plate 12A of an eccentric bearing mechanism 12 and a middle partition. It is incorporated between the plate 14. Eccentric bearing mechanism 12
Has eccentric bearing portions 12a to 12c at three places on the inner surface of the end plate 12A, and each eccentric bearing portion rotates around a support shaft 12-1 via a ball bearing 12-2. 12-3 and a revolving ball bearing 12-4 having a center of rotation at a position P offset from the center of rotation by a radius of revolution (D / 2). The revolving guide pin 16 is provided on the revolving ball bearing 12-4.
(16a, 16b, 16c) are planted. Therefore, since the eccentric bearing portions are arranged at the apexes of the equilateral triangle in a well-balanced manner, the orbital motion of the orbiting member 11 is smooth.

When one or two eccentric bearings are provided,
Since this eccentric bearing is equivalent to a link crank mechanism, if the eccentric bearing is accidentally located at a thought point (dead center) depending on the revolving position of the revolving element 11, it does not revolve in the first air pulse or in the reverse direction. It may be revolving. Therefore, in a configuration in which three eccentric bearing portions are provided as in this example, the motions at the three eccentric bearing portions are always the same, as can be proved irrationally. The idea of the child 11 can be eliminated.

Each of the orbital drive mechanisms 13a to 13c of the present embodiment has a special configuration different from a normal air cylinder. That is, as shown in FIG. 5, the revolving element driving mechanism 13 of the present example includes an air cylinder 13-1 two-dimensionally positioned by two stop pins 14-1 fitted into pin holes of the partition plate 14. Compression coil spring 13-2 housed in the cylinder chamber, and end plate 1
It is slidable between 2A and the partition plate 14 and is slidable by a compression coil spring 13-2 in the cylinder chamber. The compressed surfaces 11a to 11c of the revolutor 11 are pressed by the application of air pulses. Pressing air pistons (revolutor pressing members 13ab, 13bb, 13
cb) 13-3. Air piston 13-3
Is not connected to the revolving rotator 11 so that it can cope with high speed. The air cylinder 13-1 has a mounting screw hole 13-1a as an air supply port for screwing a joint (not shown) of an air pipe, a prismatic cylinder chamber 13-1b communicating therewith, and a bottom surface thereof. Mounting screw hole 1
It has a ring-shaped coil spring storage groove 13-1c formed around 3-1a. Air piston 13
-3 is not a closed type that closes the cylinder chamber 13-1b,
A square concave air buffer chamber 13-on the pressed surface side (front side)
The air buffer chamber 13-3a communicates with the cylinder chamber 13-1b via four small air holes A, B, C, and D. The four small ventilation holes A, B, C, and D are located at the vertices of a square, and the intersection of the diagonal lines is the mounting screw hole 13.
-1a on the center line l. A ring-shaped coil spring storage groove 13-3b is also formed on the rear surface side of the air piston 13-3. The coil spring storage groove 13-3b and the coil spring storage groove 13-1c of the air cylinder 13-1 are formed. Accommodates the above-described compression coil spring 13-2.

Due to the compression coil spring 13-2, the air piston 13-3 obtains a pushing urging force even when no air pulse is applied, and the rectangular frame-shaped rim R of the air buffer chamber 13-3a is pressed against the pressed surface 11a. Is elastically loosely pressed against As described above, the elastic normal compression of the orbiting rotor 11 from three directions is caused by the spring biasing force of the remaining two non-exciting phases on the orbiting rotor 11 at the end of one excitation phase. Because it is superior, it is possible to suppress the overshoot angle of the step. Also, the compression coil spring 1
3-2 and the air buffer chamber 13-3a communicating with the cylinder chamber 13-1 via the small ventilation holes A, B, C and D, the compressed air of the air pulse is generated in the cylinder chamber 13-1b in the excitation phase.
And the air piston 13-3 is fed forward, whereby the revolving rotator 11 is pushed by the rim R and pushed out by the stroke L. In the pushing process, the compressed air also flows into the air buffer chamber 13-3a through the small air holes A, B, C, and D, so that a direct air pressure is also applied to the pressed surface 11a of the revolutor 11, The rotator 11 is pushed out by the rigid contact and the air pressure transmission by the rim R. Since the air piston has a concave cross section, the area of the rear surface is larger than the opening area. In the pushing process, the differential pressure of the air pressure is superimposed on the spring urging force, and the rim R is pressed against the pressed surface 11a more strongly. And no pneumatic leaks occur. Air buffer room 1
The compressed air nodules in 3-3a function as air cushions. In the present embodiment, the significance of having such an air cushion effect is to eliminate the sliding contact between the pressing surface of the air piston 13-3 and the pressed surface of the revolving element 11, thereby reducing the contact resistance. That is, since the revolving element 11 revolves, the pressed surface 11a performs a two-dimensional movement. On the other hand, the air piston 13 presses the pressed surface 11a.
-3 is a one-dimensional motion (linear motion).
A sliding motion occurs in the surface tangential direction between the pressing surface of 3-3 and the pressed surface of the revolve 11. Air buffer room 13
By providing -3a, it is possible to reduce the area of rigid contact, reduce the drive loss, and prevent the sliding surface from deteriorating, just as in an air skirt of a hovercraft. The air piston 13-3 has four small ventilation holes A, in order to smoothly move in the cylinder chamber 13-1b in parallel without biting.
B, C, and D are formed at the vertices of a square, and the intersection of the diagonal lines is positioned on the center line 1 of the mounting screw hole 13-1a. , B, C, and D branch into the air buffer chamber 1
36-3a so as to flow into one portion without bias. In addition, since air release is suppressed by the urging force of the coil spring, quietness can be improved. And, in this example, the cylinder chamber, air piston,
The material of the pinion, the internal gear and the like is not metal but a self-lubricating heat-resistant plastic, which has the advantages of light weight and no lubrication.

The stem 22a of the pinion 22 is inserted into the central shaft hole 11d of the revolving revolving member 11 with a tight fit tolerance. Of course, the pinion 22 may be formed integrally with the revolving rotator 11. Further, in this example, the center of gravity S of the revolutor 11 coincides with the axis of the pinion 22, but the output shaft 21a
When it is necessary to take out the revolving element 11 from the revolving element 11, the center of gravity S of the revolving element 11 and the axis of the pinion 22 may be offset. Further, the revolving motion of the revolving element 11 may not be directly linked to the revolving motion of the pinion 22, but may be transmitted indirectly via a transmission mechanism. As this transmission mechanism, a slider crank mechanism, a revolution diameter enlargement / reduction mechanism, or the like can be used.

The output shaft 21a of the internal gear 21 is supported on the end plate 23 via ball bearings 23a and 23b. In this example, through holes 30a are formed at four corners of the end plate 12a, the partition plate 14, and the end plate 23, and through bolts 30b are inserted into these through holes 30a, and nuts (see FIG. (Not shown). Such a through bolt 30b
The clamping between the end plate 12a and the partition plate 14 by the above will affect the pinching force on the air piston 13-3 unless the tightening force is adjusted, and the free movement of the air piston 13-3 will be affected. There is a risk of inhibition. For example, in use at high temperatures, the pinching force on the air piston 13-3 increases due to thermal expansion, so that the movement becomes slightly worse. As a measure to alleviate the pinching force due to this thermal expansion, for example, if a spring washer is attached to the through bolt 30b, the spring washer absorbs the increased tightening force. Further, since the through bolt 30b itself is a cause of the tightening force, the fixing by the through bolt 30b is stopped.
Fixing the air cylinder 13 and the end plate 12a with a set screw, the air cylinder 13 and the partition plate 14
And fix it with another set screw.

[0034]

As described above, according to the present invention, the orbital member is restricted only to the orbital motion by the orbital guide mechanism.
It is characterized in that the orbital drive mechanism drives the orbital element with a force acting in a direction passing through a point that cyclically changes each time an air pulse is supplied from among the n equal points of the orbital circle from the orbital center. . Therefore, the following effects are obtained.

The orbital element revolves stepwise at an orbital angle of 2π / n radian in synchronization with a pulse along an orbital guide mechanism. At the end point of each step, the direction of the force acting on the orbit is substantially orthogonal to the orbital direction, and the work at that time disappears, so that the orbit is easily stopped at the end point. For this reason, a stepping air motor with a high step angle can be realized.

Such a stepping air motor that advances in synchronization with an air pulse can be used at a high temperature, and can be used in a semiconductor inspection apparatus provided in a constant temperature bath.
It can be used as a fine positioning motor of C package. In other words, since the X, Y, Z, and θ axes can be controlled at a high temperature, the fine pitch IC package can be inspected at a high temperature. In addition, since the air drive is used, no electromagnetic noise is generated, and the measurement environment does not need to be electrically disturbed.

Assuming that the revolving diameter of the revolving member is D and the linear motion strokes of the plurality of pneumatic linear actuators for revolving the revolving member are L, L = D ｛1-co
If the relational expression of s (2π / n)｝ / 2 holds, the end point of the step is pushed out, so that there is substantially no overshoot angle of the orbit and the step of 2π / n radian with high precision is obtained. The orbit revolves around the corner.

The pneumatic linear motion actuator includes a pressing member that performs a feeding operation by the air pulse supplied to the cylinder chamber of the air cylinder and presses a pressed surface of the revolving member without being connected to the revolving element. In a configuration in which the member has a concave air buffer chamber that opens to the pressed surface side and a vent that communicates the air buffer chamber with the cylinder chamber, the pressing member is not connected to the revolving rotator. In this state, the pressing member operates at a high speed following the high-frequency air pulse. In addition, the compressed air flows from the cylinder chamber into the concave air buffer chamber that opens to the pressed surface side through the ventilation hole by the supply of the air pulse, so that during the pressing process, compressed air nodules are generated in the air buffer chamber. Therefore, the orbit is pressed in an action manner. For this reason, even if an on-plane sliding motion occurs between the pressed surface and the pressing member, the contact resistance is small, and drive loss and abrasion can be reduced. When the ventilation holes are provided as a plurality of small ventilation holes, the compressed air flows into the air buffer chamber evenly, so that the generated compressed air nodules are less likely to be biased, and the pressed surface of the orbital rotor is pressed. Can be pressed face to face.

In the case where the cylinder chamber is provided with a spring means for constantly urging the pressing member elastically in the extending direction, even if all the pressing members are not excited, the revolving member is pressed. Since the surface is elastically pressed, no leak occurs at the initial stage of the application of the air pulse, so the rising of the pressing operation is early, and at the end of the application of the air pulse, the revolving member is pressed by another pressing member, so that the step angle is excessive. Is suppressed, and the accuracy of the step angle can be improved.

When an eccentric bearing mechanism is used as the revolving guide mechanism, the guide can be controlled by rolling contact, so that the drag (resistance) for the guide can be reduced and a smooth movement can be realized.

Further, in the configuration in which the eccentric bearing mechanism is provided at three or more locations on the revolving rotator, the idea of the eccentric bearing mechanism can be eliminated, and there is no problem even when the revolving pallet is stopped at any position. The orbital motion can be guaranteed, and the operation reliability can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic view conceptually showing a stepping air motor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the structure of the stepping air motor according to the embodiment.

FIG. 3A is a cross-sectional view taken along a line IIIa-IIIa ′ of FIG. 2; (B) is IIIb-III in FIG.
It is the cross-sectional view cut | disconnected along the b 'line.

FIGS. 4A and 4B are schematic diagrams illustrating a revolving locus of a revolving element in a three-phase air motor, and FIG. 4B is a schematic diagram illustrating a revolving locus of a revolving element in a four-phase air motor.

FIG. 5A is a partial longitudinal sectional view showing a process of extending an air piston in the present embodiment, and FIG. 5B is a partial transverse sectional view thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Revolution mechanism 11 ... Revolutor (rotor) 11a-11c ... Pressed surface 11d ... Center shaft hole 12 ... Revolution guide mechanism (eccentric bearing mechanism) 12A ... End plate 12-1 ... Support shaft 12-2 ... Ball Bearing 12-3: Rotating bearing 12-4: Revolving ball bearing 13 (13a, 13b, 13c): Revolving element drive mechanism (pneumatic linear actuator) 13-1 (13aa, 13ba, 13ca): Air cylinder 13-1a ... Mounting screw hole 13-1b ... Cylinder chamber 13-1c ... Coil spring storage groove 13-2 ... Compression coil spring 13-3 (13ab, 13bb, 13cb) ... Revolutor pressing member (air piston) 13-3a ... Air buffer Chamber 13-3b ... Coil spring storage groove 14 ... Partition plate 14-1 ... Stop pins 15a, 15b, 15c ... Radiating parts 16a, 16b, 16c Revolution guide pins 23 End plate with bush 20 Revolution / rotation conversion mechanism (hypocycloid reduction mechanism) 21 Internal gear 21a Rotation output shaft 22 Pinion 23a, 23b Ball bearing 30a ... through hole 30b ... through bolt 100 ... stepping air motor 150 ... three-way cyclic switching valve AP1, AP2, AP3 ... 3-phase air pulse P1, P2, P3 ... output port D ... revolution diameter S ... center of revolution P _1, P _2, P ₃ ... Displacement point of the center of gravity of the revolutor L ... Stroke of the air piston A, B, C, D ... Small ventilation hole R ... Rim.

Claims (10)

(57) [Claims] 1. A revolving mechanism having a revolving member that revolves in a stepwise manner at a revolving angle of 2π / n radians in synchronization with the supply of an n-phase (n ≧ 3) air pulse, and a revolving motion of the revolving member A rotation / rotation conversion mechanism for extracting rotation on an output shaft on the basis of the rotation axis, wherein the rotation mechanism controls the rotation of the revolutor in addition to the revolutor, and revolves at a predetermined revolving diameter. A revolving guide mechanism for regulating movement, and a revolving shaft driven by a force acting in a direction passing through a point among the n equally-divided points of the revolving circle from the revolving center, the point changing cyclically each time the air pulse is supplied. And a child drive mechanism. 2. The stepping air motor according to claim 1, wherein the revolving element driving mechanism is a pneumatic linear actuator arranged in each of n equally divided radial directions of the revolving element. 3. The stepping air motor according to claim 2, wherein the revolution diameter of the revolving element is D, and the linear motion stroke of the pneumatic linear actuator is L.
A stepping air motor characterized in that a relational expression of L = D {1-cos (2π / n)} / 2 is substantially satisfied. 4. The stepping air motor according to claim 3, wherein the pneumatic linear actuator performs a feeding operation by the air pulse supplied to a cylinder chamber of an air cylinder, and the pressed surface thereof is not connected to the revolving member. Has a pressing member for pressing, this pressing member,
A stepping air motor comprising: a concave air buffer chamber that opens to the pressed surface side; and a vent that communicates the air buffer chamber with the cylinder chamber. 5. The stepping air motor according to claim 4, wherein said air holes are a plurality of small air holes. 6. A stepping air motor according to claim 5, wherein said cylinder chamber has spring means for constantly urging said pressing member elastically in a feeding direction. 7. The stepping air motor according to claim 6, wherein the spring means is a coil spring. 8. The stepping air motor according to claim 1, wherein the revolution guide mechanism is an eccentric bearing mechanism using a ball bearing. 9. The stepping air motor according to claim 8, wherein the eccentric bearing mechanism is provided at three or more positions with respect to the orbit. 10. The stepping air motor defined in claim 1 is used as a positioning motor for bringing a lead of an IC package into contact with a test socket provided in a thermostat. A semiconductor inspection device characterized by comprising: