JPH03199736A - Pneumatic spring with built-in voice coil type motor - Google Patents

Abstract

PURPOSE:To eliminate the necessity for additional set up space of a motor by forming a magnet part of the voice coil type motor in the first part, having a pressure chamber, while a drive coil part of the motor in the second part having a pressure chamber which communicates with this pressure chamber. CONSTITUTION:A pneumatic spring comprises the first part 40 having a pressure chamber 40b and the second part 42 having a pressure chamber 42b. A voice coil type motor is provided between the first and second parts 40, 42 and constituted of a magnet part 44 and a drive coil part 46. The magnet part 44 is formed of an iron core 44a and a permanent magnet 44b, and the iron core 44a is integrally built in a top part end face side of a housing 40a by which the first part 40 is formed. The permanent magnet 44b is integrally secured to an internal wall surface of an outer side annular part 44a1 of the iron core 44a, and the drive coil part 46 is mounted to a cylinder part 42c integrally suspended from a top part wall of a housing 42a by which the second part 42 is formed. By the above mentioned constitution, design is facilitated with no additional space required for the voice coil type motor.

Description

[Detailed Description of the Invention] [Summary] This invention relates to air springs in general, and in particular to air springs that are suitable for performing active vibration damping control on air spring type vibration isolation tables, and which has a built-in voice coil type motor. The first part has a pressurizing chamber, the second part has a pressurizing chamber communicating with the pressurizing chamber of the first part, and the first part has a pressurizing chamber. In the air spring in which the first part and the second part can be displaced relative to each other via a diaphragm, the first part is formed with a magnet part of a voice coil type motor, and the second part is formed with a voice coil type motor. The present invention constitutes an air spring characterized by forming a drive coil portion of a motor.

[Industrial application field]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to air springs, and more particularly to air springs suitable for use in air spring type vibration isolation tables.

[Conventional technology]

An air spring generally consists of a first part having a pressurizing chamber, and a second part having a pressurizing chamber communicating with the pressurizing chamber of the first part. The parts are displaceable relative to each other via the diaphragm. As an application field of such an air spring, it is known that it is used, for example, in a vibration isolation table of a vertical X-ray exposure stage. With this type of air spring type vibration isolation table, it is possible to set its -order natural resonance frequency in the low frequency range, thereby preventing the vertical X-ray exposure stage from being affected by external vibrations in the high frequency range. has been done. However, such an air spring type vibration isolation table cannot escape from the influence of vibrations in the low frequency range, so in order to perform proper exposure work on the vertical x@exposure stage, vibrations in the low frequency range can be suppressed. It is necessary to do so.

As a technique for suppressing low-frequency vibrations of an air spring type vibration isolator, it has been proposed to detect the vibration displacement of the air spring type vibration isolator and perform feedback control to cancel the detected vibration displacement.

Referring to FIG. 3, an air spring vibration isolation table 10 incorporating such feedback control is shown. The air spring type vibration isolation table 10 includes a rectangular mounting plate or surface plate 12 on which a vertical X-ray exposure stage (not shown) is mounted, for example, and four air springs 14 that support this surface plate 12 at its four corners. (two of which are shown in FIG. 2). Each air spring 14 consists of a first portion 14a having a pressurizing chamber, and a second portion 14b having a pressurizing chamber communicating with the pressurizing chamber of the first portion 14a. The second portion 14b can be displaced relative to each other via a diaphragm (not shown).

In FIG. 3, a feedback control or damping device is configured to damp vibrations in a vertical plane of the surface plate 12. In FIG. The vibration damping device includes non-contact displacement detection sensors 16a and 16b that detect vibration displacement on opposite side surfaces of the surface plate 12;
Voice coil motors 18a and 18b that drive and displace the opposing side surfaces of the surface plate 12 in the vertical direction.
and control circuits 20a and 20b that respectively control the driving of motors 18a and 18b according to the detected values of sensors 16a and 16b.

Each sensor 16a, 16b is fixed to the outer casing of a motor 18a, 18b, and a non-detecting member 24a, 24b of the sensor 16aS16b is fixed to an actuation rod 22a, 22b of the motor 18a, 18b. Actuation rod 2
2a and 22b are connected to bracket members 27a and 27b via universal joints 26a and 26b, and these bracket members 27a and 27b are respectively fixed to opposite side surfaces of the surface plate 12. Voice coil motor 18a
, 18b are movable in the vertical direction. Therefore, when the surface plate 12 vibrates in the vertical plane, the sensors 16a, 16b and the non-detecting members 24a, 24b
The vertical distance between the two will change. Each sensor 16
a and 16b generate eddy currents in the non-detection members 24a and 24b, and detect the amount of displacement with respect to the non-detection members 24a and 24b by detecting the strength of the magnetic field generated by the eddy currents. Note that when a voltage is applied to the motors 18a, 18b, the actuating rods 22a, 22b take displacement positions according to the applied voltage.

Each control circuit 20a, 20b is an A/D converter 28a, 28
b and 30a, 3Qb, controllers 32a, 32b
, D/A converters 34a, 34b.

It consists of drive circuits 36a and 36b. A of control circuit 20a
/D converters 28a and 30a are each connected to sensor 16a.
and 16b into digital data, and A/D converters 28b and 3 of the control circuit 20b.
0b converts the detected displacement values from the sensors 16a and 16b, respectively, into digital data. In the controllers 32a and 32b, which may be configured with a microcomputer or the like,
A feedback amount (for suppressing vibration of the surface plate 12) is calculated based on each of the displacement data obtained from the sensors 16a and 16b.

Next, the controllers 32a, 32b output drive signals corresponding to the calculation results to the drive circuits 36a, 36b via the D/A converters 34a134b. At this time, predetermined voltages are applied to the voice coil motors 18a, 18b from the drive circuits 36a, 36b based on the drive signals, and as a result, the motors 18a, 18b are connected to the surface plate 12.
The surface plate 12 is driven and displaced in the vertical direction on the opposite side surface side to damp the vibration. Such feedback control is performed constantly (for example, every 1 ms), and even if vibration is induced in the surface plate 12, the vibration is immediately suppressed, so that the surface plate 12 quickly returns to an equilibrium state. I will do it.

[Problem to be solved by the invention]

In the case of feedback control as described above, it is necessary to install not only an air spring but also a voice coil motor in the space below the surface plate. In addition, in the example shown in Figure 3, we have explained the case where the voice coil motor is installed only on one opposing side of the surface plate, but in order to reliably suppress vibrations in the vertical plane of the surface plate, Therefore, it is necessary to install a voice motor on the other opposite side of the surface plate. For this reason, the installation space for voice coil motors is often subject to restrictions. Furthermore, air spring type vibration isolators are usually used together with various types of equipment, such as exposure equipment, so the installation space for the voice coil motor is also limited by such equipment, and in some cases In some cases, it may not be possible to secure installation space for a voice coil motor.

Therefore, an object of the present invention is to provide an air spring that is particularly suitable for performing active vibration damping control in an air spring type vibration isolation table, and that has a built-in voice coil type motor.

[Means to solve the problem]

According to the present invention, a first part having a pressurizing chamber;
An air spring consisting of a pressurizing chamber in the part and a second part having a pressurizing chamber communicating with the part, the first part and the second part being able to be displaced relative to each other via a diaphragm. An air spring is constructed in which a magnet portion of a voice coil type motor is formed in a first portion, and a drive coil portion of the voice coil type motor is formed in a second portion.

[For production]

In the air spring according to the invention, the magnet part of the voice coil motor is formed in the first part of the air spring, while the drive coil part of the voice coil motor is formed in the second part of the air spring. Therefore, no matter what state of motion the air spring is under, it is possible to arbitrarily displace the second portion with respect to the first portion by applying a driving voltage to the driving coil portion. Become.

〔Example〕

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

FIG. 1 shows an air spring according to the invention in longitudinal section, which air spring consists of a first part 40 and a second part 42. As shown in FIG. In this embodiment, the first part 40 is configured as a fixed part, which is a housing 4 having a cylindrical shape.
Consists of 0a. A pressure chamber 40b is formed within the housing 40a, and high-pressure air is supplied to the pressure chamber 40b from an appropriate high-pressure air source (not shown) via an air supply pipe 40C provided on the wall of the housing 40a. .

On the other hand, the second part 42 is configured as a movable part, and consists of a housing 42b having a cylindrical shape.

A pressure chamber 42b is formed within the housing 42a, and this pressure chamber 42b is communicated with a pressure chamber 40b of the first portion 40, as will be described later.

A voice coil motor is provided between the first and second portions 40 and 42 of the air spring, which is connected to the magnet portion 44.
and a drive coil section 46. The magnet portion 44 of the voice coil motor includes a cylindrical iron core 44a and a sleeve-shaped permanent magnet 44b. As shown in FIG. 1, the inside of the iron core 44a is hollowed out in an annular shape from one end surface side, that is, the upper end surface side, so that an outer annular portion 44a1 and an inner cylindrical portion 44b2 are formed in the iron core 44a. The iron core 44a is integrally incorporated and supported on the top end surface side of the housing 40a forming the first portion 40 of the air spring, and at this time the iron core 44a is supported by the housing 40a.
are placed in a concentric relationship with. Permanent magnet 4
4b is integrally fixed to the inner peripheral wall surface of the outer annular portion 44a+ of the iron core 44a. Inner columnar part 44b of iron core 44a
2 is formed with an air passage 44C along its longitudinal axis, and the air passage 44c allows the pressure chamber 40b of the first portion 40 and the pressure chamber 42b of the second portion 42 to communicate with each other. On the other hand, the drive coil section 46 is formed by winding a conductor wire into a coil, and is formed of a cylindrical section 42c that is integrally suspended from the lower surface of the top wall of the housing 42a forming the second section 42 of the air spring. Can be attached to the outside wall.

a housing 42a forming a second portion 42 of the air spring;
is held against the first portion 40 of the air spring by an annular shaped diaphragm 48. That is, the outer circumferential edge of the annular diaphragm 48 is fixed to the circumferential wall of the housing 42a, and the inner circumferential edge thereof is fixed to the annular upper end surface of the outer annular portion 44a1 of the iron core 44a. The second portion 42 of is held floating relative to the second portion 40 thereof. As shown in FIG. 1, the cylindrical portion 42c of the housing 42a enters into the annular space between the outer annular portion 44a1 and the inner cylindrical portion 44b2 of the iron core 44a, so that the drive coil portion 46 is moved by the magnetic field of the permanent magnet 44b. It will be affected by That is, when a drive voltage is applied to the drive coil section 46, the drive coil section 46 receives a driving force in the vertical direction depending on the current direction, and as a result, the second section 42 of the air spring It can be displaced in the vertical direction relative to the portion 40.

In addition, in FIG. 1, reference number 50 indicates the air passage 44c.
The diameter of the restricting orifice 50 determines the stiffness of the air spring.

Referring to FIG. 2, there is shown an example in which the air spring according to the present invention is applied to an air spring vibration isolation table as shown in FIG. In FIG. 2, the same reference numerals and symbols are used for the same components as shown in FIG. 3, except that reference numeral 14' is used for the air spring according to the invention. It goes without saying that the air spring 14' according to the present invention has a built-in voice coil motor configured as shown in FIG.

Feedback control, that is, vibration damping control explained with reference to FIG. 3, can be performed in the same way with the air spring type vibration isolation table shown in FIG. 2, but the air spring according to the present invention is used. Therefore, the air spring type vibration isolation table shown in FIG. 2 does not require any installation space for installing an additional voice coil type motor.

In the above description, the air spring according to the present invention has been explained in relation to vibration damping control of an air spring type vibration isolation table, but it goes without saying that the air spring according to the present invention can be used for other purposes as well.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when introducing active vibration damping control to an air spring type vibration isolation table, there is no need to consider the installation space of the voice coil type motor. The degree of freedom in design will be greatly improved. Further, according to the present invention, due to the characteristic that the air spring has a built-in voice coil motor, there is an advantage that it can be used for applications different from those of conventional air springs.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an air spring according to the present invention, Fig. 2 is a schematic diagram showing an example in which the air spring according to the invention is applied to an air vibration isolation table, and Fig. 3 is an air spring to which a conventional air spring is applied. It is a schematic diagram showing a type vibration isolation table. 40... First part of air spring, 40a... Housing, 40b... Pressure chamber, 4
2... Second part of the air spring, 42a... Housing, 42b... Pressure chamber,
44... Magnet part of voice coil motor, 44a...
・Iron core, 44b...Permanent magnet, 46...
Drive coil part of voice coil type motor, 48... diaphragm.

Claims (1)

[Claims] 1. A first part (40) having a pressurizing chamber (40b), and a pressurizing chamber (42b) communicating with the pressurizing chamber (40b) of the first part (40). It consists of a second part (42) having
In an air spring in which the first part (40) and the second part (42) are displaceable relative to each other via a diaphragm (48), the first part (40) An air spring characterized in that a magnet part (44) of a voice coil type motor is formed, and a drive coil part (46) of the voice coil type motor is formed in the second part (42).