JPH07279601A - Stepping air motor and semiconductor inspection device using the same - Google Patents

Abstract

(57) [Summary] [Purpose] To realize a stepping air motor that uses air pulses to enable highly reliable operation even in high-temperature and low-temperature environments and does not generate electromagnetic noise. [Steps] A stepping air motor 100 is a revolution element 1 that revolves stepwise at every revolution angle of 120 ° in pulse synchronization with the supply of three-phase air pulses (AP1, AP2, AP3).
Revolution mechanism 10 having 1 and revolution / revolution conversion mechanism (hypocycloid speed reduction mechanism) for extracting rotation on the output shaft 21a based on the revolution movement of the revolution element 11 at the revolution diameter D.
20 and 20. When three air pulses are generated, the revolving rotor 11 controls the rotation and makes one revolution of the revolution diameter D, and the pinion 22 also revolves accordingly, so that the internal gear 21 has only the difference in the number of teeth. Rotate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pneumatic motor,
In particular, the present invention relates to a stepping air motor that rotates stepwise in synchronization with an air pulse (air pressure pulse).

[0002]

2. Description of the Related Art Generally, in a semiconductor inspection device for automatically checking the electrical characteristics of an IC by automatically contacting the leads of an IC (semiconductor integrated circuit) package with a test socket,
In the process of feeding the C package to the socket, the IC packages sequentially conveyed horizontally by the conveyor are in the Z-axis direction (upward).
After pulling up to the socket, it is conveyed in the X-axis direction (horizontal) right above the socket, and then lowered in the -Z-axis direction to I
The lead of the C package is contacted with the socket, and the process of returning the IC package from the socket is performed in the reverse order of the above-described feeding process. Due to the increasing number of pins and miniaturization of IC packages in recent years, it is becoming more difficult to make accurate contact with the socket. In recent years, high temperatures (for example, 15
IC under 0 ° C) or low temperature (eg -50 ° C) atmosphere
It is becoming more and more required to check the strict specifications of the semiconductor inspection equipment that meets such strict requirements. In the process, in addition to the above-described two-axis (X-axis, Z-axis) control, two-axis control (IC package rotation angle fine adjustment θ and fine adjustment Y-axis) is required for each inspection object. That is, multi-axis control in the constant temperature bath is required.

[0003]

By the way, an electric motor is generally considered as a motor for positioning and driving an IC package with a minute resolution. However, at high temperatures, the windings of the electric motor and the insulation of the contacts are significantly deteriorated and the durability is improved. It is inferior in nature and cannot actually be used. In addition, there is a problem of inspection reliability that electromagnetic noise is generated when an electric motor is driven by electric pulses in a semiconductor inspection device that inspects electric characteristics, and thus electrically disturbs the inspection environment.

In view of the above problems, the first object of the present invention is to focus on the use of air pulses (pneumatic pulses), and to enable stepwise rotation with high reliability even in a high temperature / low temperature environment. Another object of the present invention is to realize a stepping air motor that does not need to consider the occurrence of electromagnetic noise, and a second object of the present invention is to enable the inspection of fine pitch ICs even at high and low temperatures by using the stepping air motor. The present invention is to provide a semiconductor inspection device.

[0005]

In order to solve the above problems, the present invention is intended to obtain a stepwise rotational force by an air pulse. That is, the stepping air motor according to the present invention includes a revolution mechanism including a revolution element that is stepwise revolved at every revolution angle of 2π / n radian in synchronization with the supply of n-phase (n ≧ 3) air pulses. The present invention is characterized by having a revolution / spin conversion mechanism for extracting a rotation motion on an output shaft based on the revolution motion of the revolution member. Here, the revolution / rotation conversion mechanism may be a hypocycloid reduction mechanism having an internal gear and a pinion that rotates internally. It is possible to configure the internal gear to perform an orbital motion and the pinion to perform an orbital motion.However, in a downsized motor configuration, conversely, the pinion follows an orbital rotor and an internal gear. It is desirable to have a structure having an output shaft.

Here, as a concrete structure of the revolution mechanism, in addition to the revolution mechanism, there is a revolution guide mechanism for controlling the revolution of the revolution mechanism to regulate the revolution motion of a predetermined revolution diameter, and for the air pulse. It is possible to have n revolving rotor drive mechanisms that revolve the revolving rotor by a revolution angle of 2π / n with the arrival of one shot. The orbital drive mechanism is a pneumatic linear actuator arranged in the radial direction of equal division of the orbit of the orbit, and a pneumatic linear actuator that linearly expands or contracts the orbital in the direction of the revolution center by the in-phase air pulse. It may be a dynamic actuator. In this case, when the revolution diameter of the revolution element is D and the linear motion stroke of the pneumatic linear motion actuator is L, L = D is substantially satisfied.
It is desirable that the relational expression {1-cos (2π / n)} / 2 holds.

As a concrete construction of this pneumatic direct-acting actuator, there is a pressing member which performs a feeding operation by the air pulse supplied to the cylinder chamber of the air cylinder and presses the pressed surface of the revolving rotor without connecting it. This pressing member has a concave air buffer chamber that opens to the pressed surface side and a vent hole that connects the air buffer chamber and the cylinder chamber. Further, it is desirable that the vent hole be a plurality of small vent holes, and that the cylinder chamber be provided with a spring means for elastically always urging the pressing member in the feeding direction. A coil spring is suitable 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.
Further, it is desirable to provide the eccentric bearing mechanism at three or more places on the orbital rotor.

Further, the stepping air motor having the above-mentioned structure is suitable for use in a high temperature environment, and the leads of the IC package are contacted with the test socket provided in the constant temperature chamber in the semiconductor inspection device. It can be used as a positioning motor for driving.

[0010]

When a series of n-phase air pulses are supplied, the revolution element of the revolution mechanism makes one revolution without rotating, and the revolution movement of the revolution element causes the output shaft of the revolution / spin conversion mechanism to rotate.

With one air pulse, the orbiter has an orbital angle of 2π.
Since it revolves by / n radian, 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 the pulse number of the quotient obtained by dividing it by the step angle. Such an air motor which rotates stepwise in synchronism 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 thermostat in a semiconductor inspection device. . In other words, since the X-, Y-, Z-, and θ-axis control under high temperature becomes possible, the fine-pitch IC package can be inspected under high temperature. Moreover, since it is driven by air, electromagnetic noise is not generated and the measurement environment is not electrically disturbed.

When a hypocycloid speed reduction mechanism having an internal gear and a pinion that rotates inward is adopted as the revolution / rotation conversion mechanism, the revolution is converted into the rotation, and at the same time, a predetermined reduction ratio for one revolution. As a result, the resolution of the rotation angle can be increased. The internal gear may be interlocked with the revolving rotor to rotate the pinion, but if the outer internal gear revolves, the movable region becomes wider, which is inconvenient for downsizing the motor. Therefore, if the pinion rotating inwardly on the internal gear is revolved in association with the revolving rotor to rotate the internal gear, there is no protruding movable region, and the motor can be downsized.

By the way, there is known an air motor that rotates the crankshaft by connecting the tips of rods of a plurality of air cylinders to a crankpin. When used as a servomotor, it is necessary to detect the rotation of the crankshaft and perform open / close feedback control of a solenoid valve or the like. However, according to the present invention, since the stepwise rotation is performed by the air pulse drive, feedback control is not necessary and the configuration of the control system can be eliminated.

As described above, a specific structure of the revolution mechanism requires the revolution element, the revolution guide mechanism, and the n revolution element drive mechanisms (n-phase excitation phases). In general, a pneumatic linear motion actuator arranged in the radial direction of n equal divisions of the revolution, which directly expands and contracts the revolution in the direction of the revolution center by the air pulse of the same phase. It can be an actuator. Assuming that the revolution diameter of the revolution element is D and the linear motion stroke of the pneumatic linear motion actuator is L, L = D {1-cos (2π / n)}
If the relational expression / 2 holds, 2π / n with high accuracy
The orbital revolves at a step angle of radian.

Further, the pneumatic linear actuator according to the present invention has a pressing member which is not connected to the revolving rotor and presses the surface to be pressed when the air pulse supplied to the cylinder chamber of the air cylinder performs the feeding operation. This pressing member has a concave air buffer chamber that opens to the pressed surface side and a vent hole that connects the air buffer chamber and the cylinder chamber. According to such a pneumatic direct-acting actuator, since the pressing member is not connected to the revolving element, the pressing member operates by following the high-frequency air pulse. Further, since the compressed air flows from the cylinder chamber through the ventilation hole into the concave air buffer chamber opening to the pressed surface side by the supply of the air pulse, compressed air nodules are generated in the air buffer chamber during the pressing process, Therefore, the orbiter is pressed in action. For this reason, even if there is a slide movement on the surface 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, compressed air is evenly flowed into the air buffer chamber, so that the compressed air nodules that are generated are less likely to be biased, and the pressed surface of the orbiter is less likely to be biased. Can be pressed face-to-face. Further, in the case where the cylinder chamber is provided with spring means for elastically always urging the pressing member in the feeding direction, even if all the pressing members are not excited, the elastic force is exerted on the pressed surface of the orbiter. Since it is pushed automatically, leakage does not occur at the beginning of the application of the air pulse, the rising of the pressing operation is fast, and at the end of the application of the air pulse, the revolution element is pushed by another pressing member, so overshoot of the step angle is suppressed. To be done. Also, since air bleeding is suppressed again, quietness can be improved.

When an eccentric bearing mechanism is used as the revolving guide mechanism, guide regulation can be achieved by rolling contact, so that the drag force (resistance) for the guide can be reduced.
You can achieve smooth movement. Further, in the configuration in which the eccentric bearing mechanism is provided at three or more places on the revolving rotor, the thought point of the eccentric bearing mechanism can be eliminated, and the revolving motion that does not interfere even if the revolving rotor is stopped at any position. realizable.

[0017]

Embodiments of the present invention will now 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, and FIG. 2 is a vertical sectional view showing the structure of the stepping air motor.
2A is a cross-sectional view taken along the line IIIa-IIIa 'in FIG. 2, and FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb' in FIG.

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

The stepping air motor 100 is pulse-synchronized by the supply of three-phase air pulses (AP1, AP2, AP3) from a three-way circulation switching valve (rotary valve) 150, and revolves revolving stepwise at every revolving angle of 120 °. Revolution mechanism 10 having a child (rotor) 11, and its revolving element 1
The output shaft 21a has a revolution / spin conversion mechanism (hypocycloid reduction mechanism) 20 for extracting rotation on the basis of the revolution motion of the revolution diameter D of 1.

The revolution mechanism 10 includes a revolution guide mechanism 12a to 12c (12) in addition to the revolution element 11, and a revolution element drive mechanism (pneumatic pressure element) that revolves the revolution element 11 stepwise by 120 ° at the arrival of each air pulse. Linear motion actuator) 13a-
13c (13). The orbiter 11 is shaped like an equilateral triangle with the three pressed surfaces 11a to 11c, and the radiating portions 15a to 1 that integrally project outward from each apex.
Revolution guide pins 16a to 16c are planted in 5c in the thickness direction of the revolution element 11. The revolution guide mechanism 12 is a mechanism that regulates the revolution guide pin 16 in a locus having a diameter D, and may be an annular guide groove into which the revolution guide pin 16 is inserted, or a crank mechanism using a link. In this example, as will be described later, the eccentric bearing mechanism is configured such that the revolving ball bearing which supports the revolving guide pin 16 and the revolving bearing having the revolving center O of the revolving guide pin 16 as a rotation center are eccentric.

The orbiter drive mechanisms 13a to 13c are air cylinders 13 that receive supply of air pulses AP1 to AP3.
aa, 13ba, 13ca, and a rotator pressing member (air pressing member that pushes the pressed surfaces 11a to 11c toward the revolving center (center of gravity) of the revolving rotor 11 by linearly expanding and contracting due to increase and decrease of the air pressure in the cylinder chamber. Piston) 13ab, 13
bb and 13cb, and three revolving rotor drive mechanisms 1
3a to 13c are 120 with respect to the revolution center S of the revolution element 11.
They are arranged in three radial directions at intervals of °. The revolution / rotation conversion mechanism 20 of this example is a hypocycloid speed reduction mechanism, and has a pinion (external gear) fixed to the rotator 11 and an output shaft 21a, and has a smaller number of teeth than the pinion 22, as will be described later. The pinion 22 has a pitch circle larger by a difference and meshes in an inversion direction, and the pinion 22 has an internal gear 21 that rotates by a 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 example, it may be constituted by an orbiting internal gear and a pinion having a rotation output shaft.

In such a principle configuration, when the three-way circulation switching valve 150 communicating with the compressed air source operates in a predetermined sequence, the output ports P1 to P3 are output.
The air pulses A1 to A3 are cyclically supplied to the revolving rotor drive mechanism 13 of the stepping air motor 100 via.
That is, the air pulse A1 of the first phase is the air cylinder 13a.
The air pulse A2 of the second phase, which is delayed by 120 ° to the phase a, is supplied to the air cylinder 13ba, and the air pulse A3 of the third phase, which is delayed by 120 ° phase from the air pulse A2, is supplied to the air cylinder 13ac. By supplying these series of air pulses, each revolution member pressing member 13a
b, 13bb, and 13cb are sequentially extruded by the stroke L in the arrow direction (direction toward the center of the revolution element). First, when the first-phase air pulse A1 is supplied,
Since the orbiting member pressing member 13ab pushes the pressed surface 11a of the orbiting member 11 while extending in the direction of the arrow, the orbiting member 11 is translated from the starting position indicated by the solid line in FIG. 1 to the ending position indicated by the alternate long and short dash line. This parallel movement process is, for example, that the center of gravity of the revolution element 11 moves from the point P ₁ to the point P ₂ , but even if the revolution element pressing member 13ab moves linearly in the direction of the arrow, the revolution element 11 moves.
Does not move linearly, but is controlled by the revolution movement of the revolution guide mechanisms 12a to 12c that are revolution guide means.
The center of gravity of the circle is 120 ° of the revolution diameter D of the revolution center S from the point P ₁ .
The point P ₂ is reached via an arc. When the second-phase air pulse A2 is supplied to the air cylinder 13ba after stepping at the revolution angle of 120 °, the revolution element pressing member 13bb is extended in the arrow direction and pushes the pressed surface 11b of the revolution element 11. Therefore, the revolving rotor 11 revolves from the starting position of the one-dot chain line shown in FIG. Similarly, when the third-phase air pulse A3 is then supplied to the air cylinder 13ca, the rotator pressing member 13cb pushes the pressed surface 11c of the rotator 11 while being extended in the direction of the arrow. From the starting position indicated by the chain double-dashed line shown in FIG. 1 to the end position indicated by the solid line, the orbital diameter D is revolved by a revolution angle of 120 °, and one revolution is completed. Therefore, when three air pulses are generated, the revolution element 11 restrains the rotation and makes one revolution of the revolution diameter D. For example, in the three-way circulation switching valve 150 of this example, an air pulse of 90 pulses / sec is supplied, so that the revolution element 11 revolves 30 times per second.

Now, when one air pulse is applied, the revolution element 11 surely revolves by a step angle of 120 °,
Consider whether the center of gravity is away from point P ₁ and coincides with point P ₂ . When the frequency of the air pulse is relatively low and the air pressure is not too high, the revolution pressing member 13ab is pushed out by the stroke L = 3D / 4 by one air pulse, and the center of gravity of the revolution 11 is pushed out by this stroke. Four
It is brought from point P ₁ to point P ₂ as shown in (a).
At the starting point P ₁ , the angle formed by the orbital tangential direction T and the pressing force F is 30 °, and the orbiter 11 starts to revolve while receiving a comparatively light drag, and at the position where the orbital angle becomes 30 °, the orbital tangential direction T is obtained.
And the pressing force F becomes zero, and then the angle between them gradually increases until it reaches the point P ₂ and becomes 90 °.
1 stops. The orbiter 1 by the orbiter pressing member 13ab
Even if the center of gravity of 1 is directly pushed to the point P ₂ , the center of gravity of the orbiter 11 has its own inertia in the revolving process of 120 ° in an unloaded state. There is concern that it will pass by ₂ . However, in reality, even when there is no load, friction of the revolution guide mechanism 12 and friction of the revolution / rotation conversion mechanism 20 exist, and the revolution pressing member 13ab stops at the push-cut level of the revolution pressing member 13ab. Since this exerts a stopper function, the point will not be excessively overrun from the point P ₂ . As will be described later in the embodiment shown in FIG. 2, the revolving rotor drive mechanism 13 is provided with a coil spring so that when the center of gravity reaches the point P ₂ , the braking force by the spring biasing force acts. . Therefore, immediately after the stroke L is completely pushed, the center of gravity only vibrates slightly before and after the vicinity of the point P ₂ , and the accuracy of the step rotation angle is high.

On the other hand, if the frequency of the air pulse is increased,
It is conceivable that the revolution element 11 may not reach the step angle of 120 ° during one air energizing period (one-third period of one cycle), resulting in a step out state. Such a problem is the revolution 1
1 tends to occur when the inertia is large, the load is high, or the air pressure is low. The simplest measure is to increase the air pressure, for example, linearly to set it to a sufficient value when high speed rotation is expected. This example is a three-phase air motor that uses a three-phase air pulse, but as can be easily understood, a four-phase air motor that uses a four-phase air pulse and a multi-phase air motor of more than that can be constructed. For example, in a four-phase air motor, as shown in FIG. 4 (b), the center of gravity of the revolving element revolves one revolution stepwise in the order of Q ₁ → Q ₂ → Q ₃ → Q ₄ → Q ₁ . One step angle is 90 °, stroke L
At that time, the revolution diameter D '= 2L. In this way, in a multi-phase air motor having more than three phases, the step angle is reduced and the rotational resolution (indexing of the rotational angle) is improved. However, since four or more rotator driving mechanisms are required, the number of parts increases and the miniaturization is hindered. From this point as well, it can be said that the three-phase motor is suitable. In general, in the case of an n-phase motor, the following relational expression is established between the revolution diameter D and the linear motion stroke L in order to make an accurate step angle of 2π / n radian.

L = D {1-cos (2π / n)} / 2 In this way, the revolution element 11 revolves once with the revolution diameter D by three air pulses. Since the pinion 22 is integrally formed with or fixed to the revolving element 11, the pinion 22 does not rotate but revolves along the same trajectory as that of the revolving element 11. When the revolution element 11 revolves once as shown by points P ₁ → P ₂ → P ₃ → P ₁ , the internal gear 21 meshed with the pinion 22.
Rotates by the difference in the number of teeth. In this example, 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, so one revolution of the rotator 11 causes the internal gear 21 to rotate 360 ° / 30. = Rotate only 12 °. That is, 1
The output air pulse causes the output shaft 21a to rotate 4 °. The revolution / rotation conversion mechanism 20 of course converts revolutions into rotation, but since it is a hypocycloid reduction mechanism, it has a reduction ratio of 30 and improves rotation angle indexing resolution. If a hypocycloid speed reduction mechanism having a speed reduction ratio higher than this is used, the resolution can be further improved.

Next, a specific description of the present example will be made with reference to FIGS. Stepping air motor 10 of this example
No. 0 has a small external dimension with a vertical, horizontal, and height of about 2.5 cm, which is a substantially rectangular parallelepiped. The rotator drive mechanism 13 is separated from the end plate 12A of the eccentric bearing mechanism 12 by a 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 about a support shaft 12-1 via a ball bearing 12-2. 12-3 and a revolution ball bearing 12-4 having a rotation center at a position P offset from the rotation center by a revolution radius (D / 2). This revolution ball bearing 12-4 has a revolution guide pin 16
(16a, 16b, 16c) are planted. Therefore, since the eccentric bearing portions are arranged in a well-balanced manner at the vertex positions of the equilateral triangle, the revolution movement of the revolution element 11 is smooth.

When the eccentric bearing portion is one or two,
Since this eccentric bearing part is equivalent to the crank mechanism of the link, if the eccentric bearing part happens to be at a thought point (dead point) depending on the revolution position of the rotator 11, it will not revolve with the first air pulse or will move in the opposite direction. It is possible that it will revolve around the earth. Therefore, in the configuration in which the eccentric bearing portions are provided at three locations as in this example, the motions at the three eccentric bearing portions are always the same movement, as can be reasonably proved, and as a result, the revolution The thoughts of child 11 can be resolved.

Unlike the ordinary air cylinder, each of the revolution drive mechanisms 13a to 13c of this embodiment has a special structure. That is, as shown in FIG. 5, the revolving rotor drive mechanism 13 of this example has an air cylinder 13-1 which is two-dimensionally positioned by two retaining pins 14-1 fitted in the pin holes of the partition plate 14. And the compression coil spring 13-2 housed in the cylinder chamber and the end plate 1
It is sandwiched between 2A and the partition plate 14 and is slidable, and is pushed out and urged by its compression coil spring 13-2 in the cylinder chamber, and the pressed surfaces 11a to 11c of the rotator 11 are pushed by the air pulse. Air piston for pressing (revolution element pressing members 13ab, 13bb, 13
cb)) 13-3. Air piston 13-
No. 3 is not connected to the revolving rotor 11, so that it can cope with speeding up. The air cylinder 13-1 includes 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. And a ring-shaped coil spring housing groove 13-1c formed around the mounting screw hole 13-1a. Air piston 1
3-3 is not a closed type that closes the cylinder chamber 13-1b, but an air buffer chamber 1 having a quadrangular concave shape on the pressed surface side (front surface side).
3-3a, and this air buffer chamber 13-3a communicates with the cylinder chamber 13-1b through the four small vent holes A, B, C, D. The four small ventilation holes A, B, C, D are located at the apexes of a square, and the intersections of their diagonals are located on the center line 1 of the mounting screw hole 13-1a. 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. The compression coil spring 13-2 described above is housed in and.

Due to the compression coil spring 13-2, the air piston 13-3 obtains the biasing force even when the air pulse is not applied, and the rectangular frame-shaped rim R of the air buffer chamber 13-3a has the pressed surface 11a. It is pressed loosely and elastically. As described above, the elastic normal compression from the three radiation directions on the orbiter 11 causes the spring force due to the remaining two non-excited phases on the orbiter 11 at the end of one excited phase, as described above. Since it is superior, it is possible to suppress the overshoot angle of stepping. Also, compression coil spring 1
3-2 and the air buffer chamber 13-3a communicating with the cylinder chamber 13-1 via the small vent holes A, B, C, and D, the compressed air of the air pulse is generated in the excitation phase in the cylinder chamber 13-1b.
And the air piston 13-3 is fed forward, whereby the 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 ventilation holes A, B, C, D, so that a direct air pressure is also applied to the pressed surface 11a of the rotator 11, The rotator 11 is pushed out by the rigid contact and 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. Therefore, in the pushing process, the differential pressure of the air pressure is superimposed on the spring biasing force, and the rim R is strongly pressed against the pressed surface 11a. However, air pressure leakage does not occur. Air buffer chamber 1
The compressed air nodule in 3-3a functions as an air cushion. In the present example, the significance of having such an air cushion effect is to eliminate sliding contact between the pressing surface of the air piston 13-3 and the pressed surface of the revolving rotor 11 and reduce the contact resistance. That is, since the orbiter 11 revolves, the pressed surface 11a is performing two-dimensional movement, while the air piston 13 that pushes the pressed surface 11a.
-3 is a one-dimensional motion (linear motion), so the air piston 1
Between the pressing surface 3-3 and the pressed surface of the orbiter 11, a sliding motion is generated in the surface tangential direction. Air buffer chamber 13
By providing -3a, similarly to the air skirt of the hovercraft, the area of the rigid contact is reduced, the drive loss is reduced, and the deterioration of the sliding surface can be prevented. The air piston 13-3 has four small vent holes A, in order to smoothly move in parallel in the cylinder chamber 13-1b without biting.
B, C, and D are formed at the apex positions of the squares, and the intersections of their diagonals are located on the center line 1 of the mounting screw hole 13-1a. , B, C, D branched air flow is the air buffer chamber 1
It is designed to flow into a part of 36-3a without being biased. Further, since the air bleeding is suppressed by the biasing force of the coil spring, quietness can be improved. The cylinder chamber, air piston, orbiter,
The material of the pinion, internal gear, etc. is not metal, but heat-resistant plastic with self-lubricating property, which has advantages of weight reduction and oil-free.

The stem 22a of the pinion 22 is inserted into the central shaft hole 11d of the revolving rotator 11 with an interference fit. Of course, the pinion 22 may be formed integrally with the revolution element 11. In addition, in this example, the center of gravity S of the rotator 11 and the axis of the pinion 22 coincide with each other, but the output shaft 21a
When it is necessary to separate and take out from the orbiter 11, the center of gravity S of the orbiter 11 and the axis of the pinion 22 may be offset. Further, the revolution movement of the revolution element 11 may not be directly connected to the revolution movement of the pinion 22, but may be indirectly transmitted via a transmission mechanism. As the transmission mechanism, a slider crank mechanism, a revolution diameter enlarging / reducing mechanism, or the like can be used.

The output shaft 21a of the internal gear 21 is supported by the end plate 23 via ball bearings 23a and 23b. In this example, through holes 30a are formed at the four corners of the end plate 12a, the partition plate 14, and the end plate 23. Through bolts 30b are inserted into these through holes 30a, and nuts (see FIG. It is fastened and fixed with (not shown). Such through bolt 30b
For tightening between the end plate 12a and the partition plate 14 due to, unless the tightening force is adjusted, the pinching force with respect to the air piston 13-3 is affected, and the free movement of the air piston 13-3 is prevented. May interfere. For example, in use under high temperature, the sandwiching force with respect to the air piston 13-3 increases due to thermal expansion, and the movement thereof becomes a little worse. As a measure to alleviate the pinching force by 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 causes the tightening force, the fixing by the through bolt 30b is stopped, the fixing by the set screw between the air cylinder 13 and the end plate 12a, and the air cylinder 13 and the partition plate 14 are performed. Make sure to use another set screw for fixing.

[0033]

As described above, the present invention is a stepping air motor driven by an air pulse,
It is characterized in that an orbital revolution is revolved stepwise by an air pulse and then this revolving movement is converted into a rotation movement. Therefore, the following effects are obtained.

With one air pulse, the revolution shaft revolves by the revolution angle of 2π / n, and therefore the output shaft rotates by the step angle corresponding to this. Therefore, in order to obtain a desired rotation angle, it is sufficient to supply the pulse number of the quotient obtained by dividing the rotation angle by the advance angle, and feedback control is not required. Such an air motor which rotates stepwise in synchronism 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 thermostat in a semiconductor inspection device. . In other words, since the X-, Y-, Z-, and θ-axis control under high temperature becomes possible, the fine-pitch IC package can be inspected under high temperature. Moreover, since it is driven by air, electromagnetic noise is not generated and the measurement environment is not electrically disturbed.

When a hypocycloid speed reduction mechanism having an internal gear and a pinion that internally rotates is adopted as the revolution / rotation conversion mechanism, the revolution is converted into the rotation, and at the same time, a predetermined reduction ratio for one revolution. As a result, the resolution of the rotation angle can be increased.

When the pinion rotating inwardly on the internal gear is revolved by interlocking with the revolving rotor to rotate the internal gear,
Since the pinion only revolves in the inner gear internal region, the motor can be downsized.

When the revolution diameter of the revolution element is D and the linear motion strokes of the plurality of pneumatic linear motion actuators for revolving the revolution element are L, substantially L = D {1-co
If the relational expression s (2π / n)} / 2 holds, there is practically no overshooting angle of the orbiter, and 2π / n with high accuracy is obtained.
The orbital revolves at a step angle of radian.

As a pneumatic direct-acting actuator, there is a pressing member that performs a feeding operation by the air pulse supplied to the cylinder chamber of the air cylinder and presses the surface to be pressed without being connected to the revolving rotor. In a configuration in which the member has a concave air buffer chamber that opens to the pressed surface side and a vent hole that communicates the air buffer chamber and the cylinder chamber, the pressing member is not connected to the revolving element. Since it is in the state, the pressing member operates at high speed by following the high-frequency air pulse. Further, since the compressed air flows from the cylinder chamber through the ventilation hole into the concave air buffer chamber opening to the pressed surface side by the supply of the air pulse, compressed air nodules are generated in the air buffer chamber during the pressing process, Therefore, the orbiter is pressed in action. For this reason, even if there is a slide movement on the surface 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, compressed air is evenly flowed into the air buffer chamber, so that the compressed air nodules that are generated are less likely to be biased, and the pressed surface of the orbiter is less likely to be biased. Can be pressed face-to-face.

Further, when the cylinder chamber is provided with spring means for elastically always urging the pressing members in the feeding direction, all the pressing members are pressed by the revolving element even when they are not excited. Since the surface is elastically pressed, leakage does not occur at the beginning of the application of the air pulse, so the rising of the pressing operation is fast, and at the end of the application of the air pulse, the revolution element is pressed by another pressing member, so the advance angle is too far. 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 regulation can be achieved by rolling contact, so that the drag force (resistance) for the guide can be reduced and a smooth motion can be realized.

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

[Brief description of 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 vertical cross-sectional view showing the structure of a stepping air motor according to this embodiment.

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

FIG. 4A is a schematic diagram showing a revolution trajectory of a revolution element in a three-phase air motor, and FIG. 4B is a schematic diagram showing a revolution trajectory of an revolution element in a four-phase air motor in the present embodiment.

FIG. 5A is a partial vertical cross-sectional view showing a feeding process of the air piston in the present embodiment, and FIG. 5B is a partial horizontal cross-sectional view thereof.

[Explanation of Codes] 10 ... Revolution Mechanism 11 ... Revolutions (Rotor) 11a to 11c ... Pressed Surface 11d ... Central 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 ... Revolution ball bearing 13 (13a, 13b, 13c) ... Revolving rotor drive mechanism (pneumatic direct acting actuator) 13-1 (13aa, 13ba, 13ca) ... Air cylinder 13-1a ... Mounting screw hole 13-1b ... Cylinder chamber 13-1c ... Coil spring housing groove 13-2 ... Compression coil spring 13-3 (13ab, 13bb, 13cb) ... Revolution element pressing member (air piston) 13 -3a ... Air buffer chamber 13-3b ... Coil spring storage groove 14 ... Intermediate partition plate 14-1 ... Stop pin 15a, 1 5b, 15c ... Radiating part 16a, 16b, 16c ... Revolution guide pin 23 ... Bush end plate 20 ... Revolution / spin 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 circulation switching valve AP1, AP2, AP3 ... Three-phase air pulse P1, P2, P3 ... Output port D ... Revolution diameter S ... Revolution center P _1, P _2, P ₃ ... Kotenko centroid displacement point L ... stroke a of the air piston, B, C, D ... small vents R ... rim.

Claims (13)

[Claims] 1. An orbital mechanism having an orbital that revolves stepwise at an angle of revolution of 2π / n radian in synchronism with the supply of n-phase (n ≧ 3) air pulses, and an orbital motion of the orbital. A stepping air motor having a revolution / revolution conversion mechanism for extracting a rotation motion on an output shaft based on the. 2. The stepping air motor according to claim 1, wherein the revolving / spinning conversion mechanism is a hypocycloid reduction mechanism having an internal gear and a pinion that rotates inward. 3. The stepping air motor according to claim 2, wherein the pinion revolves revolvingly following the revolving rotor, and the internal gear has the output shaft. 4. The stepping air motor according to claim 1, wherein, in addition to the revolution element, the revolution mechanism controls rotation of the revolution element to have a predetermined revolution diameter. A stepping air motor having a revolution guide mechanism for restricting revolution movement and having n revolution drive mechanisms for revolving the revolution by a revolution angle of 2π / n when one air pulse arrives. 5. The stepping air motor according to claim 4, wherein the revolution driving mechanism is an air pressure linear actuator arranged in a radial direction of equal division of the revolution, and the revolution center is generated by the in-phase air pulses. A stepping air motor, which is a pneumatic direct-acting actuator that linearly expands and contracts the revolution element in a predetermined direction. 6. The stepping air motor according to claim 5, wherein the revolution diameter of the revolution element is D, and the linear motion stroke of the pneumatic linear motion actuator is L.
A stepping air motor, wherein the relational expression L = D {1-cos (2π / n)} / 2 is substantially satisfied. 7. The stepping air motor according to claim 6, wherein the pneumatic direct-acting actuator performs a feeding operation by the air pulse supplied to a cylinder chamber of an air cylinder, and a surface to be pressed of the non-coupling rotor is not connected to the revolution element. Has a pressing member for pressing,
A stepping air motor comprising: a concave air buffer chamber that opens toward the pressed surface side; and a vent hole that connects the air buffer chamber and the cylinder chamber. 8. The stepping air motor according to claim 7, wherein the ventilation holes are a plurality of small ventilation holes. 9. The stepping air motor according to claim 8, wherein the cylinder chamber has spring means for elastically always urging the pressing member in the feeding direction. 10. The stepping air motor according to claim 9, wherein the spring means is a coil spring. 11. The stepping air motor according to claim 4, wherein the revolution guide mechanism is an eccentric bearing mechanism using a ball bearing. 12. The stepping air motor as set forth in claim 11, wherein the eccentric bearing mechanism has a structure with respect to the orbiter.
A stepping air motor, which is provided in more than one place. 13. A stepping air motor as defined in any one of claims 1 to 12 is used as a positioning motor for contacting a lead of an IC package with a test socket provided in a constant temperature bath. A semiconductor inspection device characterized by comprising: