JP2010174913A - Vibration eliminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure high damping characteristic, in a vibration eliminating device which elastically supports a vibration elimination object relative to a base, while attaining reduction in size and stabilization of vibration eliminating performance of the device. <P>SOLUTION: The vibration eliminating device 1 which elastically supports a microscope 15 relative to a table 13 includes: a lower spring case 7 opened upward, which is placed on the table 13; an upper spring case 9 opened downward, which is attached to the microscope 15 side; a coil spring 3 housed between both the spring cases 7 and 9; and a ring rubber 5 attached to a bottom wall part 17 of the lower spring case 7 and disposed within loops 3a, 3a, etc. of the coil spring 3 so as to contact with the coil spring 3 from the inside. The coil spring 3 is formed of a square wire having a substantially rectangular sectional shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration isolation device that elastically supports a vibration isolation body with respect to a base.

  Conventionally, in a precision instrument such as a microscope or a semiconductor exposure apparatus, a vibration isolator using an air spring is used as a leg of the precision instrument in order to insulate vibration from the floor and keep the precision instrument at a fixed position. It is known. In recent years, in order to simplify the structure of the vibration isolator, a coil spring is sometimes used instead of an air spring constituted by a diaphragm or a piston.

  By the way, when the external force frequency transmitted to the coil spring approaches the natural frequency of the coil spring itself, surging that increases the vibration occurs. Therefore, in the vibration isolator and the vibration isolator using the coil spring, surging is performed to suppress surging. A prevention member is often provided.

For example, in Patent Document 1, an internal member made of an elastic part or a viscoelastic part is extended in the central axis direction of the spring at a position facing the diameter direction in a loop of a coil spring made of a round wire having a circular cross section. By arranging and connecting the pair of internal members with an elastic body bent in an arc shape, the internal member is urged so as to be constantly pressed against the inner circumferential surface of the loop of the coil spring by the elastic force of the elastic body. An anti-vibration device is disclosed in which surging of a coil spring is prevented by pressing the internal member.
JP-A-8-210439

  However, in the case of using a vibration isolator and a vibration isolator using a coil spring made of a round wire as the leg of a precision instrument such as a microscope or a semiconductor exposure apparatus, as in the above-mentioned Patent Document 1, the following problems There is.

  That is, even if the vibration is several microns, the image is blurred during observation with a microscope, for example, and the exposure is adversely affected with a semiconductor exposure apparatus. For example, these precision instruments require high attenuation characteristics, but are made of a round wire. In the vibration isolator using the coil spring, the coil spring and the internal member arranged in the loop of the coil spring are in line contact with each other, and the contact area between the coil spring and the internal member is reduced. Characteristics may not be obtained.

  Also, considering the dimensional balance with precision equipment, the vibration isolator used as these legs is required to be downsized, but in order to secure a predetermined spring constant with a coil spring made of a round wire, Since the volume (spring height and spring outer diameter) needs to be larger than a certain level, there is a problem that it is difficult to reduce the size of the vibration isolator.

  Furthermore, in a vibration isolator using a coil spring made of a round wire, the internal member is deformed so as to follow the outer peripheral surface of the coil spring having a circular cross section, and easily enters between the windings of the coil spring. Thus, when the internal member enters between the windings of the coil spring, the contraction of the coil spring is hindered, and apparently, the spring constant of the coil spring is increased compared to the normal contraction of the coil spring, There is a problem that the vibration isolation performance of the vibration isolation device becomes unstable.

  The present invention has been made in view of such points, and an object of the present invention is to reduce the size and the size of the vibration isolator in a vibration isolator that elastically supports the vibration isolator against the base. The object is to provide a technique for obtaining a high damping characteristic while stabilizing the vibration performance.

  In order to achieve the above object, according to the present invention, a surging preventing member made of an elastic body is disposed in a loop of a coil spring, and a rectangular wire having a smaller spring volume than a coil spring made of a round wire having the same spring characteristics. By using the coil spring made of, the vibration isolator is made compact and the surging preventing member and the coil spring are brought into contact with each other to ensure a large contact area.

  1st invention is a vibration isolator which elastically supports a to-be-vibrated body with respect to a base, Comprising: The 1st case member mounted on the said base and opening upwards, The above-mentioned A second case member that is attached to the vibration isolator side, is positioned above the first case member, and moves relative to the first case member in the vertical direction; A coil spring accommodated between the coil spring and a bottom wall portion of the first case member or a top wall portion of the second case member, and in the loop of the coil spring so as to contact the coil spring from the inside. And a surging preventing member made of an elastic body, and the coil spring is made of a square wire having a substantially rectangular cross section.

  In the first invention, since the coil spring is made of a rectangular wire having a substantially rectangular cross section, it does not make a line contact with the surging preventing member like a coil spring made of a round wire, but makes a surface contact. Thereby, the contact area of a coil spring and a surging prevention member becomes large, and a high damping characteristic can be obtained.

  Further, by using a coil spring made of a square wire having a smaller spring height and spring outer diameter than a coil spring made of a round wire having the same spring characteristics, the vibration isolator can be reduced in size while maintaining desired spring characteristics. Can be achieved.

  By the way, when a coil spring made of a round wire is used, the surging prevention member made of an elastic body is deformed so as to follow the outer peripheral surface of the coil spring having a circular cross section, so that it can easily enter between the windings of the coil spring. . On the other hand, in the vibration isolator of the first invention, since the coil spring made of a rectangular wire is used, the inner circumferential surface of the loop of the coil spring and the surging prevention member are in surface contact almost uniformly, and the surging prevention member is It becomes difficult to enter between the windings of the coil spring. Thereby, the coil spring can be contracted normally, and the vibration isolation performance of the vibration isolation device can be stabilized.

  According to a second invention, in the first invention, the surging preventing member is a substantially cylindrical elastic body disposed in a loop of the coil spring so that a central axis thereof is substantially horizontal. When at least a part of the outer peripheral surfaces of both sides facing in the substantially horizontal direction across the central axis is pressed inward by the inner peripheral surface of the loop of the coil spring, it is substantially elliptical or substantially long when viewed from the horizontal direction. The both sides of the anti-surging member are deformed in a circular shape, and the outer peripheral surface of a columnar member extending in the vertical direction is disposed in the cylinder of the anti-surging member, and the inner peripheral surface of the loop of the coil spring And is curved so as to be along the inner circumferential surface of the loop when viewed from above and below.

  In the second invention, the outer peripheral surface of the substantially cylindrical elastic body (surging prevention member) is kept in contact with the inner peripheral surface of the loop of the coil spring by its elastic repulsive force, and stable surging prevention performance is stabilized. Can be secured.

  In addition, since the substantially cylindrical elastic body is deformed into a substantially elliptical shape or a substantially oval shape when viewed from the horizontal direction and is inserted into the loop of the coil spring, the structure of the surging preventing member is extremely simple. Thus, the assembling work of the surging preventing member to the coil spring can be easily performed.

  Further, a cylindrical member extending in the vertical direction is disposed in the cylinder of the surging preventing member, and both side portions of the surging preventing member are sandwiched between the outer peripheral surface of the cylindrical member and the inner peripheral surface of the loop of the coil spring. As a result, the loop is curved along the inner circumferential surface of the loop as viewed from above and below. The curving of both sides of the anti-surging member in this way and the use of a square wire having a substantially rectangular cross section as the coil spring, the loops of the coil spring and the outer peripheral surface of the both sides of the elastic body The inner peripheral surface is more easily brought into surface contact. Thereby, the contact area of a coil spring and a surging prevention member becomes large reliably, and a much higher damping characteristic can be acquired.

  In a third aspect based on the second aspect, the surging preventing member is recessed below the lower end of the coil spring in the bottom wall portion of the first case member or of the second case member. The top wall is attached to a counterbore recess formed so as to be recessed above the upper end of the coil spring.

  As described above, as a surging preventing member, a substantially cylindrical elastic body is arranged in the loop of the coil spring so that its central axis is substantially horizontal, and is substantially elliptical or oval when viewed from the horizontal direction. In the deformed one, the central portion in the vertical direction of the elastic body extends substantially linearly in the vertical direction along the loop inner peripheral surface of the coil spring, while the upper and lower end portions of the elastic body have an R portion. Inevitably occurs, and at the R portion, the outer peripheral surface of the elastic body and the inner peripheral surface of the loop are not in contact with each other.

  Therefore, in the third invention, the elastic body is recessed below the lower end of the coil spring on the bottom wall portion of the first case member, or on the top wall portion of the second case member than the upper end of the coil spring. By attaching to a counterbore recess formed so as to be recessed upward, the R portion generated at the lower end or upper end of the elastic body is accommodated in the counterbore recess. As a result, in the vertical direction, the portion where the coil spring and the R portion of the elastic body overlap is shortened, so that the distance between the bottom wall portion of the first case member and the top wall portion of the second case member is narrow and the size of the elastic body is small. Even if the length (length in the up-down direction in the deformed state) is limited, the length of the portion where the outer peripheral surface of the elastic body and the inner peripheral surface of the loop do not contact can be shortened. Therefore, the contact area between the coil spring and the surging preventing member can be reliably ensured, and higher damping characteristics can be obtained.

  According to a fourth aspect of the present invention, in the first to third aspects of the invention, the surging preventing member has an upper end that contacts the second case member before the first case member, or The lower end of the second case member is set to a size that comes into contact with the first case member before the second case member.

  As described above, the second case member is located above the first case member, moves relative to the first case member in the vertical direction, and a coil spring is accommodated between the two cases. For example, when the amplitude is large, the second case member moves downward until a part of the second case member and a part of the first case member come into contact with each other.

  Here, in the fourth aspect of the invention, the surging preventing member has its upper end in contact with the second case member before the first case member, or its lower end is first before the second case member. Since the size is set so as to abut against the case member, before the part of the second case member and the part of the first case member abut, the upper end or the lower end of the surging preventing member made of an elastic body The second or first case member comes into contact.

  Thus, since the surging preventing member also functions as a stopper, it is possible to suppress the impact caused by the contact between the first case member and the second case member from being transmitted to the vibration isolator, and to provide a large amplitude. The vibration control effect at the time can be enhanced.

  According to a fifth invention, in any one of the first to fourth inventions, each of the case members is substantially cylindrical, and the outer diameter of one of the case members is the other of the two case members. The case member is formed smaller than the inner diameter of the case member, and an outer projection is formed on the outer peripheral surface of the side wall portion of the one case member. The inner peripheral surface is formed with an inner protrusion protruding inside the case so as to face the outer protrusion in the vertical direction. The outer protrusion is in an unloaded state, and the one case member is The inner protrusion is engaged so as not to be detached from the other case member.

  In the fifth aspect of the invention, by engaging the outer protrusion and the inner protrusion so that the vibration isolator is assembled or when the vibration isolator is transported, the load is once again returned to the vibration isolator. When applying a load, separation of both case members can be prevented, and the axes can be easily aligned. Thereby, since the inclination of the coil spring is suppressed, both side portions of the surging preventing member are surely pressed against the inner circumferential surface of the loop of the coil spring.

  In a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the outer surface of the side wall portion of the one case member is vertically arranged so as to guide the inner protrusion portion to the outer protrusion portion. An inclined portion that is inclined toward the outer side of the case as it goes toward the outer protruding portion in the direction is formed. On the inner peripheral surface of the side wall portion of the other case member, the outer protruding portion is guided to the inner protruding portion. As described above, an inclined portion that is inclined toward the inner side of the case as it goes toward the inner protrusion in the vertical direction is formed.

  In the sixth invention, on the outer peripheral surface of the side wall portion of one case member, there is an inclined portion that inclines toward the outer side of the case toward the outer protrusion side in the vertical direction so as to guide the inner protrusion portion to the outer protrusion portion. On the inner peripheral surface of the side wall portion of the other case member formed, an inclined portion that inclines toward the inner side of the case toward the inner protruding portion side in the vertical direction so as to guide the outer protruding portion to the inner protruding portion. Therefore, when the first case member and the second case member are assembled, the outer and inner protrusions that are in contact with the inclined portions are attracted to each other even if the axes of the case members are displaced. Be guided to. This makes it easier to align the axes of the two case members during assembly.

  According to the vibration isolator of the present invention, since the coil spring is made of a rectangular wire having a substantially rectangular cross section, the contact area between the coil spring and the surging preventing member is increased and high damping characteristics can be obtained. At the same time, it becomes difficult for the surging preventing member to enter between the windings of the coil spring, and the vibration isolation performance of the vibration isolation device can be stabilized. Further, by using a coil spring made of a square wire having a smaller spring height and spring outer diameter than a coil spring made of a round wire having the same spring characteristics, the vibration isolator can be downsized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing an assembled state of a vibration isolation device according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a load application state of the vibration isolation device, and FIG. FIG. 4 is a cross-sectional view taken along the line III-III of FIG. 4, and FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. The vibration isolator 1 is used as a leg portion of a microscope (vibrated object) 15 and elastically supports the microscope 15 with respect to a table (base) 13.

  As shown in FIGS. 1 and 2, the vibration isolator 1 includes a lower spring case (first case member) 7 placed on a table 13 via a disk-shaped base 11, and the lower spring case 7. An upper spring case (second case member) 9 disposed on the upper side and attached to the bottom of the microscope 15 and a coil that is concentrically disposed between the two spring cases 7 and 9 and receives the load of the microscope 15 A ring rubber (elastic body) as a surging preventing member attached to the spring 3 and the bottom wall portion 17 of the lower spring case 7 and fitted into the loops 3a, 3a,. And 5.

  The lower spring case 7 is a cast molded product formed in a bottomed cylindrical shape having a bottom wall portion 17 and a lower side wall portion 27, and is placed on the table 13 in an open state.

  A circular recess 17a having a circular cross section is formed at the center of the bottom wall portion 17 of the lower spring case 7, and the lower end of the coil spring 3 is in contact with the bottom surface of the circular recess 17a. The lower end of the coil spring 3 is accommodated. In this way, the lower end portion of the coil spring 3 is accommodated in the circular concave portion 17a that is one step lower than the upper surface of the bottom wall portion 17, so that the loops 3a, 3a of the coil spring 3 can be moved even if the coil spring 3 moves in the horizontal direction. ,... Are in contact with the side surfaces defining the circular recess 17a, so that the lower spring case 7 and the coil spring 3 are less likely to be misaligned.

  Further, the bottom wall portion 17 of the lower spring case 7 is formed with a counterbore recess 17b having a circular cross section that is recessed further downward than the circular recess 17a at the center of the circular recess 17a. The counterbore recess 17b is formed to have the same size as the inner diameter of the loops 3a, 3a,... Of the coil spring 3, and the ring rubber 5 is attached to the counterbore recess 17b.

  Further, a screw insertion hole 17c penetrating the bottom wall portion 17 in the vertical direction is formed at the center portion of the bottom wall portion 17 (spot facing recess 17b) of the lower spring case 7. The screw insertion hole 17c is formed in the vicinity of the bottom surface of the counterbore recess 17b, and a large-diameter hole 17d having the same diameter as the head of a cross-recessed countersunk machine screw 45, which will be described later. The shaft portion of the cross-recessed countersunk machine screw 45 and the small-diameter hole 17f having the same diameter are communicated with each other via a tapered portion 17e having a constriction.

  Furthermore, two bolt insertion holes 17g, 17g extending in the vertical direction are formed symmetrically on the bottom wall portion 17 of the lower spring case 7 with the screw insertion hole 17c interposed therebetween. The base 11 is attached to the lower end of the vibration isolator 1 by screwing a bolt (not shown) into the bolt insertion holes 17g and 17g.

  Outer ridges (outer protrusions) 27 a and 27 a are formed at the upper end of the lower side wall 27 of the lower spring case 7 so as to protrude outward from the outer peripheral surface of the case (radially outward). As shown in FIG. 5, the outer ridges 27 a and 27 a are intermittently sandwiched between two locations on the outer peripheral surface of the lower side wall 27 and sandwich the central axis Z 1 of the lower spring case 7 (vibration isolation device 1). It is formed symmetrically. Each of the outer ridges 27 a and 27 a is provided over a range of approximately a quarter of the outer periphery of the lower side wall 27.

  On the outer peripheral surface of the lower side wall portion 27 of the lower spring case 7, on the lower side of each outer ridge portion 27a, 27a (on the bottom wall portion 17 side with respect to the outer ridge portion 27a, 27a), upward (vertical direction). The lower inclined portions 27b and 27b are formed so as to be inclined from the outer peripheral surface of the lower side wall portion 27 toward the outer side of the case toward the outer protrusion portion 27a side). More specifically, each of the lower inclined portions 27b and 27b is formed in an isosceles triangle shape having a substantially right-angled vertical cross section, and is formed on the outer peripheral surface of the lower side wall portion 27 and the lower surface of each of the outer ridge portions 27a and 27a. It has an inclined surface inclined approximately 45 degrees so as to connect the intermediate portion in the protruding direction.

  On the other hand, the upper spring case 9 is a cast molded product formed in a cylindrical shape having a top wall portion 19 and an upper side wall portion 29, and a mounting bolt protruding from the upper surface of the top wall portion 19. 9a is fastened to the bottom of the microscope 15 in a state of opening downward. The upper spring case 9 has substantially the same height as the lower spring case 7. Further, the inner diameter of the upper spring case 9 is formed larger than the outer diameter of the lower spring case 7, whereby the upper spring case 9 is covered with the upper side of the lower spring case 7. On the other hand, it can be moved relative to the vertical direction.

  A circular recess 19a having a circular cross section is formed at the center of the top wall portion 19 of the upper spring case 9, and the circular recess 19a is in a state where the upper end of the coil spring 3 is in contact with the ceiling surface of the circular recess 19a. The upper end of the coil spring 3 is housed in In this way, the upper end of the coil spring 3 is accommodated in the circular recess 19a that is one step higher than the upper surface of the top wall portion 19, so that the loop 3a, 3a of the coil spring 3 can be moved even if the coil spring 3 tries to move in the horizontal direction. ,... Are in contact with the side surfaces that define the circular recess 19a, and therefore, the misalignment between the upper spring case 9 and the coil spring 3 is unlikely to occur.

  An inner ridge protruding from the inner peripheral surface of the upper spring side wall 29 to the inside of the case (inward in the radial direction) at the lower end of the upper side wall 29 of the upper spring case 9 so as to face the outer ridges 27a (Inner protrusions) 29a and 29a are formed. As shown in FIG. 6, the inner ridge portions 29 a and 29 a are symmetrically provided at two locations on the outer peripheral surface of the upper side wall portion 29 with the central axis Z 2 of the upper spring case 9 (vibration isolation device 1) interposed therebetween. Is formed. Each of the outer ridges 27 a and 27 a is provided over a range of approximately a quarter of the outer periphery of the upper side wall 29.

  On the inner peripheral surface of the upper side wall portion 29 of the upper spring case 9, on the upper side of the inner ridge portions 29a, 29a (on the top wall portion 19 side with respect to the inner ridge portions 29a, 29a), downward (in the vertical direction). Upper inclined portions 29b and 29b are formed so as to incline from the inner peripheral surface of the upper side wall portion 29 toward the inside of the case as it goes to the inner protruding portion 29a side). More specifically, each of the upper inclined portions 29b and 29b is formed in a substantially right-angled isosceles triangle shape, and protrudes from the inner peripheral surface of the upper side wall portion 29 and the upper surfaces of the inner ridge portions 29a and 29a. It has an inclined surface inclined approximately 45 degrees so as to connect the intermediate portion of the direction.

  In addition, substantially rectangular plate-like wife wall portions 29c and 29c are formed at both ends of the inner protrusion portion 29a and the upper inclined portion 29b. The end wall portions 29c and 29c extend in the vertical direction from the lower end of the upper side wall portion 29 to the upper end of the upper inclined portion 29b, and from the inner peripheral surface of the upper side wall portion 29 to the radial tip of the inner ridge portion 29a. Extends to the inside of the case.

  As described above, since the coil spring 3 is accommodated between the lower spring case 7 and the upper spring case 9, the lower spring case 7 and the upper spring are not loaded in the vibration isolator 1. Although the case 9 tends to be separated from each other, in the vibration isolation device 1, the lower surface of the outer ridges 27a and 27a and the inner ridge 29a provided to face the outer ridges 27a and 27a. , 29a abut against each other, as shown in FIG. 4, the outer protrusions 27a, 27a and the inner protrusions 29a, 29a are engaged with each other, and the lower spring case 7 is connected to the upper spring case 9. It is hard to come off.

  Also, when the lower spring case 7 and the upper spring case 9 rotate relatively and the outer ridges 27a, 27a and the inner ridges 29a, 29a are likely to be displaced, the outer ridge 27a. , 27a abuts against one of the end wall portions 29c, 29c,... Provided at both ends of the inner ridge portions 29a, 29a, so that the lower spring case 7 is also in the case circumferential direction. It is difficult to come off the upper spring case 9.

  Further, even when the center axis Z1 of the lower spring case 7 and the center axis Z2 of the upper spring case 9 are deviated, the radial tip of the inner protrusion 29a abuts on the lower inclined portion 27b, and the lower side The outer ridge 27a is guided to slide on the inclined surface of the inclined portion 27b, the radial tip of the outer ridge 27a abuts on the upper inclined portion 29b, and slides on the inclined surface of the upper inclined portion 29b. In this way, it is guided to the inner ridge 29a. Thus, since the centering of the center axis Z1 of the lower spring case 7 and the center axis Z2 of the upper spring case 9 is always performed, the vibration isolation performance of the vibration isolation device 1 is stabilized.

  The coil spring 3 is made of a rectangular wire having a substantially rectangular cross section. As described above, the lower end of the coil spring 3 is housed in the circular recess 17a of the lower spring case 7, and the upper end of the coil spring 3 is a circular recess of the upper spring case 9. By being housed in 19a, the spring cases 7 and 9 are concentrically arranged and accommodated. In this way, the coil spring 3 and the ring rubber 5 as the surging preventing member are in surface contact with each other by using the coil spring 3 made of a rectangular wire having a substantially rectangular cross section. The contact area between the coil spring 3 and the ring rubber 5 is larger than that using a coil spring made of a conventional round wire that comes into contact.

  The ring rubber 5 is formed by forming a rubber elastic body having damping properties into a substantially cylindrical shape having an outer diameter larger than the inner diameter of the loops 3a, 3a,... Of the coil spring 3, and its central axis is substantially horizontal. It arrange | positions in the loop 3a, 3a, ... of the coil spring 3 so that it may become. An insertion hole 5a is formed through the lower portion of the ring rubber 5, and a cylindrical spacer 25 is fitted into the insertion hole 5a.

  As shown in FIGS. 1 and 7, the spacer 25 fitted in the ring rubber 5 has a cross hole that is inserted into the screw insertion hole 17c of the lower spring case 7 from below and protrudes from the lower surface of the counterbore recess 17b. The shaft portion of the countersunk machine screw 45 is inserted. Then, a screw extending in the axial direction at the center portion of the upper portion of the shaft portion of the cross-recessed countersunk screw 45 extending above the spacer 25 via a spring washer 55 and a flat washer 65 for preventing loosening. A cylindrical boss member (cylindrical member) 35 in which a hole is formed is screwed. In this manner, the spacer 25 is sandwiched between the lower end of the boss member 35 and the lower surface of the counterbore recess 17b, whereby the ring rubber 5 is in a state (arrangement) in which the boss member 35 extending in the vertical direction is assembled in the cylinder. In the countersunk recess 17b. The ring rubber 5 is not directly tightened with the cross-recessed countersunk screw 45 and the boss member 35, but is attached to the spot facing recess 17b via the spacer 25 inserted into the insertion hole 5a of the ring rubber 5. This is because the ring rubber 5 is prevented from being bent indefinitely by being tightened with the cross-recessed flat head screw 45 and the boss member 35.

  In this way, by attaching the ring rubber 5 to the counterbore 17b that is formed in the bottom wall portion 17 of the lower spring case 7 and is recessed below the lower end of the coil spring 3, the lower end of the ring rubber 5 is attached. The length of the portion where the R portions 5c, 5c inevitably generated and the coil spring 3 overlap is shortened. In other words, the R portions 5 c and 5 c of the ring rubber 5 bulge downward from the lower end of the coil spring 3, whereby the bottom wall portion 17 of the lower spring case 7 and the top wall portion 19 of the upper spring case 9. When the lengths in the vertical direction are equal, the outer peripheral surface of the ring rubber 5 and the inner peripheral surfaces of the loops 3a, 3a,... Are compared with the ring rubber attached at the same height as the lower end of the coil spring 3. The length of the part that does not contact with is shortened.

  Further, the ring rubber 5 has both side portions 5b, 5b opposed in a substantially horizontal direction across the central axis thereof, and the outer peripheral surface is pressed inward by the inner peripheral surfaces of the loops 3a, 3a,. They are deformed into a substantially oval shape (may be a substantially oval shape) when viewed from the horizontal direction. More specifically, since the ring rubber 5 has an outer diameter larger than the inner diameter of the loops 3a, 3a,... Of the coil spring 3, the corners in the width direction of the outer peripheral surfaces of both side parts 5b, 5b are By contacting the inner circumferential surface of the loops 3a, 3a,..., The coil springs 3 are pressed inward in the diameter direction by the loops 3a, 3a,. The number of loops 3a in contact with the outer peripheral surface is increased as compared with the circular state.

  And both the side parts 5b and 5b of the ring rubber 5 are curved in the width direction of the outer peripheral surface by pressing the corners in the width direction of the outer peripheral surface against the inner peripheral surfaces of the loops 3a, 3a,. become. Here, since the cylindrical boss member 35 extending in the vertical direction is disposed in the cylinder of the ring rubber 5, both side portions 5 b and 5 b of the ring rubber 5 are connected to the outer peripheral surface of the boss member 35 and the coil spring. As shown in FIG. 3, when sandwiched between the three loops 3a, 3a,..., They are curved along the inner peripheral surface of the loops 3a, 3a,. In this way, both side portions 5b, 5b of the ring rubber 5 deformed into a substantially oval shape are curved so as to follow the inner peripheral surface of the loops 3a, 3a,. Combined with the above, the contact area between the ring rubber 5 and the coil spring 3 is remarkably increased as compared with a conventional vibration isolator using a coil spring made of a round wire. Since the coil spring 3 is made of a rectangular wire having a substantially rectangular cross section, the ring rubber 5 is wound around the coil spring 3 even though the contact area between the ring rubber 5 and the coil spring 3 is large. It is difficult to enter between 3a.

  The ring rubber 5 is set to a size such that the upper end of the ring rubber 5 comes into contact with the top wall portion 19 of the upper spring case 9 before the lower spring case 7. More specifically, the outer diameter of the ring rubber 5 is such that, in the no-load state, the vertical distance between the upper end of the oval deformed state and the ceiling surface of the circular recess 19a of the upper spring case 9 is the lower spring case 7. It is set to be shorter than the vertical distance between the upper end of the lower side wall portion 27 and the lower surface of the top wall portion 19 of the upper spring case 9. As a result, the ring rubber 5 not only prevents surging, but also serves as a stopper. As shown in FIG. 8, even when the vibration isolator 1 is in a maximum load load state (ring rubber 5 The upper end of the lower side wall portion 27 of the lower spring case 7 and the lower surface of the top wall portion 19 of the upper spring case 9 do not come into contact with each other.

-Assembly procedure of vibration isolator-
Next, an assembly procedure of the vibration isolation device 1 will be described.

  First, a cross-recessed flat head machine screw 45 is inserted into the screw insertion hole 17c from below the lower spring case 7, and the shaft portion of the cross-head countersunk machine screw 45 is projected from the lower surface of the counterbore recess 17b. Further, the spacer 25 is fitted into the insertion hole 5 a formed through the ring rubber 5.

  Then, after the shaft portion of the cross-recessed countersunk screw 45 is inserted into the hole of the spacer 25 fitted in the ring rubber 5, the shaft portion of the cross-recessed countersunk head screw 45 projecting upward from the spacer 25. A flat washer 65 and a spring washer 55 are fitted in this order.

  Next, after the boss member 35 is screwed onto the upper portion of the shaft portion of the cross-recessed countersunk screw 45, the cross-recessed countersunk head screw 45 is tightened to fix the ring rubber 5 to the counterbore recess 17b.

  Then, the coil spring 3 is pushed into the lower spring case 7 so that the upper end portion of the lightly-squeezed ring rubber 5 is fitted into the loops 3a, 3a,... Of the coil spring 3, and the lower end of the coil spring 3 is The lower spring case 7 is brought into contact with the bottom surface of the circular recess 17a. At this time, the ring rubber 5 is deformed into a substantially oval shape, and the both side portions 5b, 5b are curved so as to be along the inner peripheral surface of the loops 3a, 3a,.

  Next, the upper spring case 9 is moved to the lower spring case 7 in a state where the outer protrusions 27a, 27a of the lower spring case 7 and the inner protrusions 29a, 29a of the upper spring case 9 are shifted by approximately 90 degrees in the horizontal plane. Push it to the lower spring case 7 side so that it covers.

  The outer ridges 27a, 27a of the lower spring case 7 and the inner ridges 29a, 29a of the upper spring case 9 are displaced in the vertical direction (the outer ridges 27a, 27a are the inner ridges 29a, 29a). By the way, the upper spring case 9 is rotated about 90 degrees with respect to the lower spring case 7 to weaken the force for pushing the upper spring case 9. Then, the lower surface of the outer ridges 27a and 27a and the upper surface of the inner ridges 29a and 29a come into contact with each other, so that the outer ridges 27a and 27a and the inner ridges 29a and 29a are engaged with each other. Assembling of the vibration isolator 1 is completed.

  Even when the center axis Z1 of the lower spring case 7 and the center axis Z2 of the upper spring case 9 are slightly deviated when the force for pushing the upper spring case 9 is weakened, the tips of the inner ridges 29a and 29a are lowered. It is guided to the outer ridges 27a, 27a so as to slide on the inclined surfaces of the side inclined portions 27b, 27b, and the inner ends so that the tips of the outer ridges 27a, 27a slide on the inclined surfaces of the upper inclined portions 29b, 29b. Since it is guided to the ridges 29a, 29a, the center axis Z1 of the lower spring case 7 and the center axis Z2 of the upper spring case 9 are centered.

-Action of vibration isolation device-
Next, the operation of the vibration isolation device 1 will be described.

  First, when the normal weight in the state (1G state) in which the weight of the microscope 15 acts on the coil spring 3 and the upper spring case 9 is displaced to the lower normal position (floor vibration that is not sensed by the human body) When the spring case 9 moves up and down relatively with respect to the lower spring case 7, the coil spring 3 absorbs vibration and the ring rubber 5 functions as a low dynamic spring by damping the vibration of the coil spring 3.

  FIG. 9 is a graph showing the vertical vibration transmissibility of the vibration isolator 1 when the contact area between the coil spring 3 and the ring rubber 5 is changed in the vibration isolator 1 according to the present embodiment. In Example 1 (solid line in FIG. 9) and Example 2 (broken line in FIG. 9), a ring rubber 5 made of elastic rubber and a coil spring 3 made of a rectangular wire having a rectangular cross section were used. The contact area between the coil spring 3 and the ring rubber 5 in Example 1 was about 1.5 times the contact area between the coil spring 3 and the ring rubber 5 in Example 2.

  From FIG. 9, the resonance magnification at the natural frequency f1 of Example 1 with a large contact area between the coil spring 3 and the ring rubber 5 is clearly smaller than the resonance magnification at the natural frequency f2 of Example 2. That is, it can be seen that the higher the contact area between the coil spring 3 and the ring rubber 5, the higher the damping characteristics.

  That is, in the vibration isolator 1 according to the present embodiment, the coil spring 3 made of a rectangular wire having a substantially rectangular cross section is used. Therefore, the coil spring is more than a conventional vibration isolator using a coil spring made of a round wire. The contact area between the ring rubber 5 and the ring rubber 5 is increased, and a high damping characteristic is exhibited.

  On the other hand, when the amplitude is large, the upper spring case 9 moves greatly downward. As described above, the ring rubber 5 has a size such that the upper end of the ring rubber 5 comes into contact with the upper spring case 9 before the lower spring case 7. Therefore, the two spring cases 7 and 9 are difficult to contact. Further, when the upper end of the ring rubber 5 comes into contact with the top wall portion 19 of the upper spring case 9, the ring rubber 5 swells to further improve the damping characteristics and the spring constant of the coil spring 3. Thereby, the big movement of the upper spring case 9 is suppressed.

-Effect-
According to the present embodiment, since the coil spring 3 is made of a rectangular wire having a substantially rectangular cross section, it does not make line contact with the ring rubber 5 like a coil spring made of a round wire, but makes surface contact. . Thereby, the contact area of the coil spring 3 and the ring rubber 5 becomes large, and a high damping characteristic can be obtained.

  Further, by using a coil spring 3 made of a square wire material having a smaller spring height and spring outer diameter than a coil spring made of a round wire material having the same spring characteristics, the vibration isolator 1 is maintained while maintaining desired spring characteristics. Can be miniaturized.

  By the way, when a coil spring made of a round wire is used, the ring rubber 5 made of a rubber elastic body is deformed so as to follow the outer peripheral surface of the coil spring having a circular cross section and easily enters between the windings of the coil spring. Become. On the other hand, in the vibration isolator 1 of the present embodiment, the coil spring 3 made of a rectangular wire is used, so that the inner peripheral surfaces of the loops 3a, 3a,. The ring rubber 5 is difficult to enter between the windings 3a of the coil spring 3 due to surface contact. Thereby, the coil spring 3 can be contracted normally, and the vibration isolation performance of the vibration isolation device 1 can be stabilized.

  Further, the outer peripheral surface of the substantially cylindrical ring rubber 5 is maintained in contact with the inner peripheral surfaces of the loops 3a, 3a,. Can be secured.

  Further, since the substantially cylindrical ring rubber 5 is deformed into a substantially oval shape and is inserted into the loops 3a, 3a,... Of the coil spring 3, the structure of the ring rubber 5 becomes very simple. The assembly work of the ring rubber 5 to the coil spring 3 can be easily performed.

  A boss member 35 extending in the vertical direction is disposed in the cylinder of the ring rubber 5, and both side portions 5 b and 5 b of the ring rubber 5 are arranged on the outer peripheral surface of the boss member 35 and the loop 3 a of the coil spring 3. Are curved along the inner peripheral surface of the loop 3a, 3a,... When viewed from above and below. Combined with the curving of both side portions 5b, 5b of the ring rubber 5 and the use of a rectangular wire having a substantially rectangular cross section as the coil spring 3, both side portions 5b, 5b of the ring rubber 5 are combined. ... and the inner peripheral surfaces of the loops 3a, 3a, ... of the coil spring 3 are more easily brought into surface contact. As a result, the contact area between the coil spring 3 and the ring rubber 5 is reliably increased, and an even higher damping characteristic can be obtained.

  As described above, the ring rubber 5 is disposed in the loops 3a, 3a,... Of the coil spring 3 so that the central axis thereof is substantially horizontal, and is deformed into a substantially oval shape when viewed from the horizontal direction. The central portion of the rubber 5 in the vertical direction extends substantially linearly in the vertical direction along the inner peripheral surface of the loop 3a, 3a,... Of the coil spring 3, while the R portion 5c , 5c inevitably occur, and in the R portions 5c, 5c, the outer peripheral surface of the elastic body and the inner peripheral surfaces of the loops 3a, 3a,.

  Therefore, in the present embodiment, the ring rubber 5 is attached to a counterbore recess 17b formed in the bottom wall portion 17 of the lower spring case 7 so as to be recessed below the lower end of the coil spring 3. The R portions 5c and 5c generated at the lower end of the countersink are housed in the counterbore recess 17b. As a result, in the vertical direction, the portion where the coil spring 3 and the R portions 5c, 5c of the ring rubber 5 overlap is shortened, so that the bottom wall portion 17 of the lower spring case 7 and the top wall portion 19 of the upper spring case 9 Even if the interval is narrow and the size of the ring rubber 5 (the length in the vertical direction in the deformed state) is limited, the outer peripheral surface of the ring rubber 5 and the inner peripheral surface of the loops 3a, 3a,. The length can be shortened. Therefore, the contact area between the coil spring 3 and the ring rubber 5 can be reliably ensured, and higher damping characteristics can be obtained.

  As described above, the upper spring case 9 is located above the lower spring case 7 and moves relative to the lower spring case 7 in the vertical direction. For example, when the amplitude is large, the upper spring case 9 is It moves downward until the bottom surface of the top wall portion 19 contacts the upper end of the lower side wall portion 27 of the lower spring case 7.

  Here, in the present embodiment, the ring rubber 5 is sized such that the upper end of the ring rubber 5 comes into contact with the lower surface of the top wall portion 19 of the upper spring case 9 before the upper end of the lower side wall portion 27 of the lower spring case 7. Therefore, before the lower surface of the top wall portion 19 of the upper spring case 9 contacts the upper end of the lower side wall portion 27 of the lower spring case 7, the upper end of the ring rubber 5 and the circular shape of the upper spring case 9 are set. The ceiling surface of the recess 19a comes into contact.

  Thus, since the ring rubber 5 also functions as a stopper, it is possible to suppress the impact caused by the contact between the lower spring case 7 and the upper spring case 9 from being transmitted to the microscope 15 and at the time of large amplitude. The vibration control effect can be enhanced.

  Further, by engaging the outer ridges 27a and 27a with the inner ridges 29a and 29a, once the vibration isolator 1 is assembled, the microscope 15 is transported, etc. When the load is applied again to the vibration isolator 1 after the operation is not performed, it is possible to prevent the two spring cases 7 and 9 from being separated and to easily align their axes. Thereby, since the inclination of the coil spring 3 is suppressed, both side portions 5b, 5b of the ring rubber 5 are surely pressed against the inner peripheral surfaces of the loops 3a, 3a,.

  Further, on the outer peripheral surface of the lower side wall portion 27 of the lower spring case 7, an inclined portion that inclines toward the outer side of the case as it goes upward so as to guide the inner ridge portions 29a, 29a to the outer ridge portions 27a, 27a. 27b and 27b are formed, and on the inner peripheral surface of the upper side wall portion 29 of the upper spring case 9, the outer ridge portions 27a and 27a go downward so as to guide the inner ridge portions 29a and 29a. Since the inclined portions 29b and 29b are formed so as to be inclined toward the inside of the case, when the lower spring case 7 and the upper spring case 9 are assembled, the inclinations of these spring cases 7 and 9 are shifted even if they are misaligned. The outer and inner ridges 27a, 29a, ... that are in contact with the parts 27b, 29b, ... are guided so as to attract each other. This makes it easier to align the axes of the spring cases 7 and 9 during assembly.

(Other embodiments)
The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  In the above embodiment, the vibration isolation device 1 is used as a leg of the microscope 15, but is not limited thereto, and may be used as a leg of a semiconductor exposure apparatus, for example.

  In the above embodiment, the ring rubber 5 is attached to the bottom wall portion 17 of the lower spring case 7. However, the present invention is not limited thereto, and a counterbore recess is provided in the top wall portion 19 of the upper spring case 9. You may attach the ring rubber 5 to a recessed part.

  Furthermore, in the said embodiment, although the substantially cylindrical rubber elastic body was arrange | positioned in the loops 3a, 3a, ... of the coil spring 3 as the ring rubber 5 so that the center axis line may become substantially horizontal, it is not restricted to this, A cylindrical rubber elastic body extending in the vertical direction may be used.

  In the above embodiment, the inner diameter of the upper spring case 9 is formed larger than the outer diameter of the lower spring case 7. Conversely, the inner diameter of the lower spring case 7 is larger than the outer diameter of the upper spring case 9. You may form large.

  Furthermore, in the above embodiment, the outer and inner ridges 27a are intermittently provided at two locations on the outer peripheral surface of the lower side wall 27 of the lower spring case 7 and the lower end of the upper side wall 29 of the upper spring case 9. 27a, 29a, 29a are formed, but three or more outer and inner protrusions 27a, 29a may be formed as long as they are formed symmetrically with respect to the central axes Z1, Z2 of the lower and upper spring cases 7, 9. Good.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention is useful for a vibration isolator that suppresses propagation of floor vibrations and the like to precision instruments such as a microscope and a semiconductor exposure apparatus.

It is a longitudinal cross-sectional view which shows the assembly state of the vibration isolator which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the load state of a vibration isolator. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. It is the figure seen from the lower part of the lower spring case. FIG. 5 is a cross-sectional view of the upper spring case corresponding to FIG. 4. It is an exploded view which shows the attachment structure of a ring rubber typically. It is a longitudinal cross-sectional view which shows the maximum load load state of a vibration isolator. It is a graph which shows the vibration transmissibility of the up-down direction of a vibration isolator.

1 Vibration Isolator 3 Coil Spring 3a Loop 5 Ring Rubber (Surging Prevention Member)
5b Side 7 Lower spring case (first case member) (one case member)
9 Upper spring case (second case member) (the other case member)
13 Table (base)
15 Microscope (vibrator)
17 Bottom wall portion 17b Counterbore recess 19 Top wall portion 27 Lower side wall portion (side wall portion)
27a Outer ridge (outer protrusion)
27b Lower inclined part (inclined part)
29 Upper side wall (side wall)
29a Inner ridge (inner protrusion)
29b Upper inclined part (inclined part)
35 Boss member (cylindrical member)

Claims (6)

A vibration isolator that elastically supports a vibration isolator with respect to a base,
A first case member mounted on the base and opening upward;
A second case member that is attached to the vibration isolator side, is located above the first case member, and moves in a vertical direction relative to the first case member;
A coil spring housed between the two case members;
An elastic body is attached to the bottom wall portion of the first case member or the top wall portion of the second case member and is disposed in the loop of the coil spring so as to contact the coil spring from the inside. A surging preventing member,
The above-described coil spring is made of a rectangular wire having a substantially rectangular cross section. The vibration isolator according to claim 1, wherein
The surging preventing member is a substantially cylindrical elastic body arranged in a loop of the coil spring so that its central axis is substantially horizontal, and both side portions opposed to each other in the horizontal direction across the central axis. At least a part of the outer peripheral surface of the coil spring is inwardly pressed by the inner peripheral surface of the loop of the coil spring, and is deformed into a substantially elliptical shape or a substantially oval shape when viewed from the horizontal direction.
Both side portions of the surging preventing member are sandwiched between an outer peripheral surface of a columnar member extending in the vertical direction and disposed in a cylinder of the surging preventing member, and an inner peripheral surface of the loop of the coil spring. A vibration isolator that is curved so as to follow the inner circumferential surface of the loop when viewed from the direction. The vibration isolator according to claim 2,
The surging prevention member is recessed below the lower end of the coil spring in the bottom wall portion of the first case member, or above the upper end of the coil spring in the top wall portion of the second case member. A vibration isolation device, wherein the vibration isolation device is attached to a counterbore recess formed to be recessed. In the vibration isolator as described in any one of Claims 1-3,
The surging preventing member has an upper end that contacts the second case member before the first case member, or a lower end that contacts the first case member before the second case member. An anti-vibration device characterized in that the size is set so as to contact. In the vibration isolator as described in any one of Claims 1-4,
Each of the above case members is substantially cylindrical,
The outer diameter of one of the case members is smaller than the inner diameter of the other case member,
On the outer peripheral surface of the side wall portion of the one case member, an outer protrusion is formed protruding outward from the case. On the other hand, the inner peripheral surface of the side wall portion of the other case member is Inner protrusions that protrude inside the case are formed so as to face each other,
The vibration isolation device, wherein the outer protrusion engages with the inner protrusion so that the one case member does not separate from the other case member in a no-load state. The vibration isolator according to claim 5,
On the outer peripheral surface of the side wall portion of the one case member, an inclined portion that is inclined to the outside of the case toward the outer protrusion portion in the vertical direction is formed so as to guide the inner protrusion portion to the outer protrusion portion. On the other hand, on the inner peripheral surface of the side wall portion of the other case member, the inner protrusion portion is inclined toward the inner protrusion portion in the vertical direction so that the outer protrusion portion is guided to the inner protrusion portion. An anti-vibration device having an inclined portion.

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